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chromium / chromium / src / 141.0.7390.122 / . / third_party / blink / renderer / modules / accessibility / ax_node_object.cc
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/*
* Copyright (C) 2012, Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "third_party/blink/renderer/modules/accessibility/ax_node_object.h"
#include <math.h>
#include <algorithm>
#include <array>
#include <memory>
#include <optional>
#include <queue>
#include "base/auto_reset.h"
#include "base/containers/contains.h"
#include "base/containers/fixed_flat_set.h"
#include "base/metrics/histogram_functions.h"
#include "base/numerics/safe_conversions.h"
#include "third_party/blink/public/common/features.h"
#include "third_party/blink/public/common/input/web_keyboard_event.h"
#include "third_party/blink/public/mojom/frame/user_activation_notification_type.mojom-blink.h"
#include "third_party/blink/public/strings/grit/blink_strings.h"
#include "third_party/blink/renderer/bindings/core/v8/v8_image_bitmap_options.h"
#include "third_party/blink/renderer/core/css/counter_style_map.h"
#include "third_party/blink/renderer/core/css/css_resolution_units.h"
#include "third_party/blink/renderer/core/css/properties/longhands.h"
#include "third_party/blink/renderer/core/display_lock/display_lock_utilities.h"
#include "third_party/blink/renderer/core/dom/flat_tree_traversal.h"
#include "third_party/blink/renderer/core/dom/focus_params.h"
#include "third_party/blink/renderer/core/dom/layout_tree_builder_traversal.h"
#include "third_party/blink/renderer/core/dom/node_traversal.h"
#include "third_party/blink/renderer/core/dom/qualified_name.h"
#include "third_party/blink/renderer/core/dom/range.h"
#include "third_party/blink/renderer/core/dom/scroll_marker_group_pseudo_element.h"
#include "third_party/blink/renderer/core/dom/scroll_marker_pseudo_element.h"
#include "third_party/blink/renderer/core/dom/shadow_root.h"
#include "third_party/blink/renderer/core/dom/text.h"
#include "third_party/blink/renderer/core/editing/editing_utilities.h"
#include "third_party/blink/renderer/core/editing/markers/custom_highlight_marker.h"
#include "third_party/blink/renderer/core/editing/markers/document_marker_controller.h"
#include "third_party/blink/renderer/core/editing/position.h"
#include "third_party/blink/renderer/core/events/event_util.h"
#include "third_party/blink/renderer/core/events/keyboard_event.h"
#include "third_party/blink/renderer/core/frame/local_dom_window.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/local_frame_view.h"
#include "third_party/blink/renderer/core/frame/settings.h"
#include "third_party/blink/renderer/core/highlight/highlight.h"
#include "third_party/blink/renderer/core/html/canvas/html_canvas_element.h"
#include "third_party/blink/renderer/core/html/canvas/image_data.h"
#include "third_party/blink/renderer/core/html/custom/element_internals.h"
#include "third_party/blink/renderer/core/html/fenced_frame/html_fenced_frame_element.h"
#include "third_party/blink/renderer/core/html/forms/html_button_element.h"
#include "third_party/blink/renderer/core/html/forms/html_data_list_element.h"
#include "third_party/blink/renderer/core/html/forms/html_field_set_element.h"
#include "third_party/blink/renderer/core/html/forms/html_form_control_element.h"
#include "third_party/blink/renderer/core/html/forms/html_form_element.h"
#include "third_party/blink/renderer/core/html/forms/html_input_element.h"
#include "third_party/blink/renderer/core/html/forms/html_label_element.h"
#include "third_party/blink/renderer/core/html/forms/html_legend_element.h"
#include "third_party/blink/renderer/core/html/forms/html_opt_group_element.h"
#include "third_party/blink/renderer/core/html/forms/html_option_element.h"
#include "third_party/blink/renderer/core/html/forms/html_output_element.h"
#include "third_party/blink/renderer/core/html/forms/html_select_element.h"
#include "third_party/blink/renderer/core/html/forms/html_text_area_element.h"
#include "third_party/blink/renderer/core/html/forms/labels_node_list.h"
#include "third_party/blink/renderer/core/html/forms/radio_input_type.h"
#include "third_party/blink/renderer/core/html/forms/text_control_element.h"
#include "third_party/blink/renderer/core/html/html_anchor_element.h"
#include "third_party/blink/renderer/core/html/html_body_element.h"
#include "third_party/blink/renderer/core/html/html_details_element.h"
#include "third_party/blink/renderer/core/html/html_dialog_element.h"
#include "third_party/blink/renderer/core/html/html_directory_element.h"
#include "third_party/blink/renderer/core/html/html_div_element.h"
#include "third_party/blink/renderer/core/html/html_dlist_element.h"
#include "third_party/blink/renderer/core/html/html_element.h"
#include "third_party/blink/renderer/core/html/html_embed_element.h"
#include "third_party/blink/renderer/core/html/html_frame_element_base.h"
#include "third_party/blink/renderer/core/html/html_hr_element.h"
#include "third_party/blink/renderer/core/html/html_html_element.h"
#include "third_party/blink/renderer/core/html/html_image_element.h"
#include "third_party/blink/renderer/core/html/html_li_element.h"
#include "third_party/blink/renderer/core/html/html_map_element.h"
#include "third_party/blink/renderer/core/html/html_menu_bar_element.h"
#include "third_party/blink/renderer/core/html/html_menu_element.h"
#include "third_party/blink/renderer/core/html/html_menu_item_element.h"
#include "third_party/blink/renderer/core/html/html_menu_list_element.h"
#include "third_party/blink/renderer/core/html/html_meter_element.h"
#include "third_party/blink/renderer/core/html/html_olist_element.h"
#include "third_party/blink/renderer/core/html/html_paragraph_element.h"
#include "third_party/blink/renderer/core/html/html_permission_element.h"
#include "third_party/blink/renderer/core/html/html_plugin_element.h"
#include "third_party/blink/renderer/core/html/html_progress_element.h"
#include "third_party/blink/renderer/core/html/html_slot_element.h"
#include "third_party/blink/renderer/core/html/html_span_element.h"
#include "third_party/blink/renderer/core/html/html_summary_element.h"
#include "third_party/blink/renderer/core/html/html_table_caption_element.h"
#include "third_party/blink/renderer/core/html/html_table_cell_element.h"
#include "third_party/blink/renderer/core/html/html_table_col_element.h"
#include "third_party/blink/renderer/core/html/html_table_element.h"
#include "third_party/blink/renderer/core/html/html_table_row_element.h"
#include "third_party/blink/renderer/core/html/html_table_section_element.h"
#include "third_party/blink/renderer/core/html/html_time_element.h"
#include "third_party/blink/renderer/core/html/html_ulist_element.h"
#include "third_party/blink/renderer/core/html/media/html_audio_element.h"
#include "third_party/blink/renderer/core/html/media/html_media_element.h"
#include "third_party/blink/renderer/core/html/media/html_video_element.h"
#include "third_party/blink/renderer/core/html/parser/html_parser_idioms.h"
#include "third_party/blink/renderer/core/html/shadow/shadow_element_names.h"
#include "third_party/blink/renderer/core/html_names.h"
#include "third_party/blink/renderer/core/imagebitmap/image_bitmap.h"
#include "third_party/blink/renderer/core/input_type_names.h"
#include "third_party/blink/renderer/core/layout/hit_test_location.h"
#include "third_party/blink/renderer/core/layout/hit_test_result.h"
#include "third_party/blink/renderer/core/layout/inline/abstract_inline_text_box.h"
#include "third_party/blink/renderer/core/layout/inline/inline_cursor.h"
#include "third_party/blink/renderer/core/layout/inline/inline_node.h"
#include "third_party/blink/renderer/core/layout/inline/offset_mapping.h"
#include "third_party/blink/renderer/core/layout/layout_block_flow.h"
#include "third_party/blink/renderer/core/layout/layout_box_model_object.h"
#include "third_party/blink/renderer/core/layout/layout_html_canvas.h"
#include "third_party/blink/renderer/core/layout/layout_inline.h"
#include "third_party/blink/renderer/core/layout/layout_object.h"
#include "third_party/blink/renderer/core/layout/layout_view.h"
#include "third_party/blink/renderer/core/layout/table/layout_table.h"
#include "third_party/blink/renderer/core/layout/table/layout_table_cell.h"
#include "third_party/blink/renderer/core/layout/table/layout_table_row.h"
#include "third_party/blink/renderer/core/layout/table/layout_table_section.h"
#include "third_party/blink/renderer/core/loader/progress_tracker.h"
#include "third_party/blink/renderer/core/mathml/mathml_element.h"
#include "third_party/blink/renderer/core/mathml_names.h"
#include "third_party/blink/renderer/core/navigation_api/navigation_api.h"
#include "third_party/blink/renderer/core/page/focus_controller.h"
#include "third_party/blink/renderer/core/page/page.h"
#include "third_party/blink/renderer/core/style/computed_style_base_constants.h"
#include "third_party/blink/renderer/core/style/computed_style_constants.h"
#include "third_party/blink/renderer/core/svg/svg_a_element.h"
#include "third_party/blink/renderer/core/svg/svg_desc_element.h"
#include "third_party/blink/renderer/core/svg/svg_element.h"
#include "third_party/blink/renderer/core/svg/svg_foreign_object_element.h"
#include "third_party/blink/renderer/core/svg/svg_g_element.h"
#include "third_party/blink/renderer/core/svg/svg_svg_element.h"
#include "third_party/blink/renderer/core/svg/svg_symbol_element.h"
#include "third_party/blink/renderer/core/svg/svg_text_element.h"
#include "third_party/blink/renderer/core/svg/svg_title_element.h"
#include "third_party/blink/renderer/core/svg/svg_use_element.h"
#include "third_party/blink/renderer/core/xlink_names.h"
#include "third_party/blink/renderer/modules/accessibility/ax_block_flow_iterator.h"
#include "third_party/blink/renderer/modules/accessibility/ax_image_map_link.h"
#include "third_party/blink/renderer/modules/accessibility/ax_inline_text_box.h"
#include "third_party/blink/renderer/modules/accessibility/ax_node_object.h"
#include "third_party/blink/renderer/modules/accessibility/ax_object-inl.h"
#include "third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.h"
#include "third_party/blink/renderer/modules/accessibility/ax_position.h"
#include "third_party/blink/renderer/modules/accessibility/ax_range.h"
#include "third_party/blink/renderer/modules/accessibility/ax_relation_cache.h"
#include "third_party/blink/renderer/platform/graphics/image_data_buffer.h"
#include "third_party/blink/renderer/platform/keyboard_codes.h"
#include "third_party/blink/renderer/platform/runtime_enabled_features.h"
#include "third_party/blink/renderer/platform/text/platform_locale.h"
#include "third_party/blink/renderer/platform/text/text_direction.h"
#include "third_party/blink/renderer/platform/weborigin/kurl.h"
#include "third_party/blink/renderer/platform/wtf/text/strcat.h"
#include "third_party/blink/renderer/platform/wtf/text/string_builder.h"
#include "third_party/skia/include/core/SkImage.h"
#include "ui/accessibility/accessibility_features.h"
#include "ui/accessibility/ax_common.h"
#include "ui/accessibility/ax_role_properties.h"
#include "ui/events/keycodes/dom/dom_code.h"
#include "ui/events/keycodes/dom/keycode_converter.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/geometry/size_f.h"
#include "ui/gfx/geometry/transform.h"
#include "ui/strings/grit/ax_strings.h"
namespace blink {
namespace {
const ScrollMarkerPseudoElement* GetScrollMarker(const Node* node) {
auto* element = DynamicTo<Element>(node);
if (!element) {
return nullptr;
}
return DynamicTo<ScrollMarkerPseudoElement>(
element->GetPseudoElement(kPseudoIdScrollMarker));
}
bool IsTabsModeScrollMarker(const ScrollMarkerPseudoElement& scroll_marker) {
ScrollMarkerGroupPseudoElement* scroll_marker_group =
scroll_marker.ScrollMarkerGroup();
// ::scroll-marker can be without a ::scroll-marker-group when
// it's inside e.g. <select>.
if (!scroll_marker_group) {
return false;
}
return scroll_marker_group->ScrollMarkerGroupMode() ==
ScrollMarkerGroup::ScrollMarkerMode::kTabs;
}
// Returns `true` if `node` has ::scroll-marker and the originating
// element of its ::scroll-marker-group has scroll-marker-group property
// set to `tabs` mode.
bool IsOriginatingElementForScrollMarkerInTabsMode(const Node* node) {
const ScrollMarkerPseudoElement* scroll_marker = GetScrollMarker(node);
return scroll_marker && IsTabsModeScrollMarker(*scroll_marker);
}
// Returns `true` if `node` has inactive ::scroll-marker and the originating
// element of its ::scroll-marker-group has scroll-marker-group property
// set to `tabs` mode.
bool IsOriginatingElementForInactiveScrollMarkerInTabsMode(const Node* node) {
const ScrollMarkerPseudoElement* scroll_marker = GetScrollMarker(node);
return scroll_marker && !scroll_marker->IsSelected() &&
IsTabsModeScrollMarker(*scroll_marker);
}
bool ShouldUseLayoutNG(const blink::LayoutObject& layout_object) {
return layout_object.IsInline() &&
layout_object.IsInLayoutNGInlineFormattingContext();
}
// It is not easily possible to find out if an element is the target of an
// in-page link.
// As a workaround, we consider the following to be potential targets:
// - <a name>
// - <foo id> -- an element with an id that is not SVG, a <label> or <optgroup>.
// <label> does not make much sense as an in-page link target.
// Exposing <optgroup> is redundant, as the group is already exposed via a
// child in its shadow DOM, which contains the accessible name.
// #document -- this is always a potential link target via <a name="#">.
// This is a compromise that does not include too many elements, and
// has minimal impact on tests.
bool IsPotentialInPageLinkTarget(blink::Node& node) {
auto* element = blink::DynamicTo<blink::Element>(&node);
if (!element) {
// The document itself is a potential link target, e.g. via <a name="#">.
return blink::IsA<blink::Document>(node);
}
// We exclude elements that are in the shadow DOM. They cannot be linked by a
// document fragment from the main page:as they have their own id namespace.
if (element->ContainingShadowRoot())
return false;
// SVG elements are unlikely link targets, and we want to avoid creating
// a lot of noise in the AX tree or breaking tests unnecessarily.
if (element->IsSVGElement())
return false;
// <a name>
if (auto* anchor = blink::DynamicTo<blink::HTMLAnchorElement>(element)) {
if (anchor->HasName())
return true;
}
// <foo id> not in an <optgroup> or <label>.
if (element->HasID() && !blink::IsA<blink::HTMLLabelElement>(element) &&
!blink::IsA<blink::HTMLOptGroupElement>(element)) {
return true;
}
return false;
}
bool IsLinkable(const blink::AXObject& object) {
if (!object.GetLayoutObject()) {
return false;
}
// See https://wiki.mozilla.org/Accessibility/AT-Windows-API for the elements
// Mozilla considers linkable.
return object.IsLink() || object.IsImage() ||
object.GetLayoutObject()->IsText();
}
bool IsImageOrAltText(blink::LayoutObject* layout_object, blink::Node* node) {
DCHECK(layout_object);
if (layout_object->IsImage()) {
return true;
}
if (IsA<blink::HTMLImageElement>(node)) {
return true;
}
auto* html_input_element = DynamicTo<blink::HTMLInputElement>(node);
return html_input_element && html_input_element->HasFallbackContent();
}
bool ShouldIgnoreListItem(blink::Node* node) {
DCHECK(node);
// http://www.w3.org/TR/wai-aria/complete#presentation
// A list item is presentational if its parent is a native list but
// it has an explicit ARIA role set on it that's anything other than "list".
blink::Element* parent = blink::FlatTreeTraversal::ParentElement(*node);
if (!parent) {
return false;
}
if (IsA<blink::HTMLMenuElement>(*parent) ||
IsA<blink::HTMLUListElement>(*parent) ||
IsA<blink::HTMLOListElement>(*parent)) {
AtomicString role =
blink::AXObject::AriaAttribute(*parent, blink::html_names::kRoleAttr);
if (!role.empty() && role != "list" && role != "directory") {
return true;
}
}
return false;
}
bool IsNeutralWithinTable(blink::AXObject* obj) {
if (!obj)
return false;
ax::mojom::blink::Role role = obj->RoleValue();
return role == ax::mojom::blink::Role::kGroup ||
role == ax::mojom::blink::Role::kGenericContainer ||
role == ax::mojom::blink::Role::kRowGroup;
}
// Within a table, provide the accessible, semantic parent of |node|,
// by traversing the DOM tree, ignoring elements that are neutral in a table.
// Return the AXObject for the ancestor.
blink::AXObject* GetDOMTableAXAncestor(blink::Node* node,
blink::AXObjectCacheImpl& cache) {
// Used by code to determine roles of elements inside of an HTML table,
// Use DOM to get parent since parent_ is not initialized yet when role is
// being computed, and because HTML table structure should not take into
// account aria-owns.
if (!node)
return nullptr;
while (true) {
node = blink::LayoutTreeBuilderTraversal::Parent(*node);
if (!node)
return nullptr;
blink::AXObject* ax_object = cache.Get(node);
if (ax_object && !IsNeutralWithinTable(ax_object))
return ax_object;
}
}
// Return the first LayoutTableSection if maybe_table is a non-anonymous
// table. If non-null, set table_out to the containing table.
blink::LayoutTableSection* FirstTableSection(
blink::LayoutObject* maybe_table,
blink::LayoutTable** table_out = nullptr) {
if (auto* table = DynamicTo<blink::LayoutTable>(maybe_table)) {
if (table->GetNode()) {
if (table_out) {
*table_out = table;
}
return table->FirstSection();
}
}
if (table_out) {
*table_out = nullptr;
}
return nullptr;
}
enum class AXAction {
kActionIncrement = 0,
kActionDecrement,
};
blink::KeyboardEvent* CreateKeyboardEvent(
blink::LocalDOMWindow* local_dom_window,
blink::WebInputEvent::Type type,
AXAction action,
blink::AccessibilityOrientation orientation,
ax::mojom::blink::WritingDirection text_direction) {
blink::WebKeyboardEvent key(type,
blink::WebInputEvent::Modifiers::kNoModifiers,
base::TimeTicks::Now());
if (action == AXAction::kActionIncrement) {
if (orientation == blink::kAccessibilityOrientationVertical) {
key.dom_key = ui::DomKey::ARROW_UP;
key.dom_code = static_cast<int>(ui::DomCode::ARROW_UP);
key.native_key_code = key.windows_key_code = blink::VKEY_UP;
} else if (text_direction == ax::mojom::blink::WritingDirection::kRtl) {
key.dom_key = ui::DomKey::ARROW_LEFT;
key.dom_code = static_cast<int>(ui::DomCode::ARROW_LEFT);
key.native_key_code = key.windows_key_code = blink::VKEY_LEFT;
} else { // horizontal and left to right
key.dom_key = ui::DomKey::ARROW_RIGHT;
key.dom_code = static_cast<int>(ui::DomCode::ARROW_RIGHT);
key.native_key_code = key.windows_key_code = blink::VKEY_RIGHT;
}
} else if (action == AXAction::kActionDecrement) {
if (orientation == blink::kAccessibilityOrientationVertical) {
key.dom_key = ui::DomKey::ARROW_DOWN;
key.dom_code = static_cast<int>(ui::DomCode::ARROW_DOWN);
key.native_key_code = key.windows_key_code = blink::VKEY_DOWN;
} else if (text_direction == ax::mojom::blink::WritingDirection::kRtl) {
key.dom_key = ui::DomKey::ARROW_RIGHT;
key.dom_code = static_cast<int>(ui::DomCode::ARROW_RIGHT);
key.native_key_code = key.windows_key_code = blink::VKEY_RIGHT;
} else { // horizontal and left to right
key.dom_key = ui::DomKey::ARROW_LEFT;
key.dom_code = static_cast<int>(ui::DomCode::ARROW_LEFT);
key.native_key_code = key.windows_key_code = blink::VKEY_LEFT;
}
}
return blink::KeyboardEvent::Create(key, local_dom_window, true);
}
unsigned TextStyleFlag(ax::mojom::blink::TextStyle text_style_enum) {
return static_cast<unsigned>(1 << static_cast<int>(text_style_enum));
}
ax::mojom::blink::TextDecorationStyle
TextDecorationStyleToAXTextDecorationStyle(
const blink::ETextDecorationStyle text_decoration_style) {
switch (text_decoration_style) {
case blink::ETextDecorationStyle::kDashed:
return ax::mojom::blink::TextDecorationStyle::kDashed;
case blink::ETextDecorationStyle::kSolid:
return ax::mojom::blink::TextDecorationStyle::kSolid;
case blink::ETextDecorationStyle::kDotted:
return ax::mojom::blink::TextDecorationStyle::kDotted;
case blink::ETextDecorationStyle::kDouble:
return ax::mojom::blink::TextDecorationStyle::kDouble;
case blink::ETextDecorationStyle::kWavy:
return ax::mojom::blink::TextDecorationStyle::kWavy;
}
NOTREACHED();
}
String GetTitle(blink::Element* element) {
if (!element)
return String();
if (blink::SVGElement* svg_element =
blink::DynamicTo<blink::SVGElement>(element)) {
// Don't use title() in SVG, as it calls innerText() which updates layout.
// Unfortunately, this must duplicate some logic from SVGElement::title().
if (svg_element->InUseShadowTree()) {
String title = GetTitle(svg_element->OwnerShadowHost());
if (!title.empty())
return title;
}
// If we aren't an instance in a <use> or the <use> title was not found,
// then find the first <title> child of this element. If a title child was
// found, return the text contents.
if (auto* title_element =
blink::Traversal<blink::SVGTitleElement>::FirstChild(*element)) {
return title_element->GetInnerTextWithoutUpdate();
}
return String();
}
return element->title();
}
bool HasLayoutText(const blink::AXObject* obj) {
// This method should only be used when layout is clean.
#if DCHECK_IS_ON()
DCHECK(obj->GetDocument()->Lifecycle().GetState() >=
blink::DocumentLifecycle::kLayoutClean)
<< "Unclean document at lifecycle "
<< obj->GetDocument()->Lifecycle().ToString();
#endif
// If no layout object, could be display:none or display locked.
if (!obj->GetLayoutObject()) {
return false;
}
if (blink::DisplayLockUtilities::LockedAncestorPreventingPaint(
*obj->GetLayoutObject())) {
return false;
}
// Only text has inline textbox children.
if (!obj->GetLayoutObject()->IsText()) {
return false;
}
// TODO(accessibility): Unclear why text would need layout if it's not display
// locked and the document is currently in a clean layout state.
// It seems to be fairly rare, but is creating some crashes, and there is
// no repro case yet.
if (obj->GetLayoutObject()->NeedsLayout()) {
DCHECK(false) << "LayoutText needed layout but was not display locked: "
<< obj;
return false;
}
return true;
}
// TODO(crbug.com/371011661): Use single list marker representation for a11y.
// Accessibility is treating list markers in two different ways:
// 1. As a regular list marker object;
// 2. As a object of type none, thus ignoring the list marker, and adding the
// text as its child. Regardless of the way being used for a particular list
// item, we need to know how to connect the list marker with the next text on
// the line. `layout_object`represents the node being investigated, and `parent`
// may contain the parent of this object, if it is included in the tree.
const LayoutObject* GetListMarker(const LayoutObject& layout_object,
const AXObject* parent) {
if (layout_object.IsLayoutOutsideListMarker()) {
// This is the default case: this LayoutObject represents a list marker.
return &layout_object;
}
if (parent && parent->RoleValue() == ax::mojom::blink::Role::kNone &&
parent->GetLayoutObject() &&
parent->GetLayoutObject()->IsLayoutOutsideListMarker()) {
// The parent of the node being investigated is a list marker, so it will be
// used in the computation to connect things in the same line.
return parent->GetLayoutObject();
}
return nullptr;
}
bool ElementHasAnyAriaRelation(Element& element) {
return element.HasAnyExplicitlySetAttrAssociatedElements() ||
AXObject::HasAriaAttribute(element, html_names::kAriaActionsAttr) ||
AXObject::HasAriaAttribute(element,
html_names::kAriaActivedescendantAttr) ||
AXObject::HasAriaAttribute(element, html_names::kAriaControlsAttr) ||
AXObject::HasAriaAttribute(element,
html_names::kAriaDescribedbyAttr) ||
AXObject::HasAriaAttribute(element, html_names::kAriaDetailsAttr) ||
AXObject::HasAriaAttribute(element,
html_names::kAriaErrormessageAttr) ||
AXObject::HasAriaAttribute(element, html_names::kAriaFlowtoAttr) ||
AXObject::HasAriaAttribute(element, html_names::kAriaLabelledbyAttr) ||
AXObject::HasAriaAttribute(element, html_names::kAriaLabeledbyAttr) ||
AXObject::HasAriaAttribute(element, html_names::kAriaOwnsAttr);
}
bool IsAddedOnlyViaSpecialTraversal(const Node* node) {
// Terminology:
// * Scroll button pseudo-element: these are the left/right buttons
// automatically added for CSS carousels,
// * Scroll marker group pseudo-element: this is a group of navigation
// buttons (often dots) for controlling the CSS carousel.
// * Scroll marker pseudo-element: this is an individual navigation button.
//
// ::scroll-markers have their layout object nested under
// ::scroll-marker-group, which isn't related to its node traversal. So we
// shouldn't use node or layout traversals for this. Instead this is handled
// in AXNodeObject::AddScrollMarkerGroupChildren, and any time we walk the
// layout tree starting from ::scroll-marker-group. See the comment in
// AXNodeObject::AddScrollMarkerGroupChildren for a more detailed explanation.
if (node->IsScrollMarkerPseudoElement()) {
return true;
}
// ScrollButtons and ScrollMarkerGroup are added as siblings of their
// originating element. See `AddNodeChild`.
if (node->IsScrollMarkerGroupPseudoElement() ||
node->IsScrollButtonPseudoElement()) {
return true;
}
return false;
}
VectorOf<Node> UnpackScrollerWithSiblingControls(Element* element) {
CHECK(element->HasScrollButtonOrMarkerGroupPseudos());
// This is the order of how the pseudo-elements should appear according to
// https://drafts.csswg.org/css-overflow-5/
PseudoId ordered_pseudos[] = {
kPseudoIdScrollMarkerGroupBefore, kPseudoIdScrollButtonBlockStart,
kPseudoIdScrollButtonInlineStart, kPseudoIdScrollButtonInlineEnd,
kPseudoIdScrollButtonBlockEnd, kPseudoIdNone,
kPseudoIdScrollMarkerGroupAfter,
};
VectorOf<Node> result;
for (PseudoId pseudo_id : ordered_pseudos) {
if (pseudo_id == kPseudoIdNone) {
result.push_back(element);
} else if (auto* pseudo = element->GetPseudoElement(pseudo_id)) {
result.push_back(pseudo);
}
}
// We should have at least added the element itself.
CHECK(!result.empty());
return result;
}
void CollectLayoutTextContentRecursive(StringBuilder& builder,
const LayoutObject* object) {
if (auto* text_object = DynamicTo<LayoutText>(object)) {
builder.Append(text_object->TransformedText());
}
for (auto* child = object->SlowFirstChild(); child;
child = child->NextSibling()) {
CollectLayoutTextContentRecursive(builder, child);
}
}
} // namespace
using html_names::kAltAttr;
using html_names::kTitleAttr;
using html_names::kTypeAttr;
using html_names::kValueAttr;
using mojom::blink::FormControlType;
// In ARIA 1.1, default value of aria-level was changed to 2.
const int kDefaultHeadingLevel = 2;
// When an AXNodeObject is created with a Node instead of a LayoutObject it
// means that the LayoutObject is purposely being set to null, as it is not
// relevant for this object in the AX tree.
AXNodeObject::AXNodeObject(Node* node, AXObjectCacheImpl& ax_object_cache)
: AXObject(ax_object_cache, /*is_node_object=*/true), node_(node) {}
AXNodeObject::AXNodeObject(LayoutObject* layout_object,
AXObjectCacheImpl& ax_object_cache)
: AXObject(ax_object_cache, /*is_node_object=*/true),
node_(layout_object->GetNode()),
layout_object_(layout_object) {
#if DCHECK_IS_ON()
layout_object_->SetHasAXObject(true);
#endif
}
AXNodeObject::~AXNodeObject() {
DCHECK(!node_);
DCHECK(!layout_object_);
}
void AXNodeObject::AlterSliderOrSpinButtonValue(bool increase) {
if (!GetNode())
return;
if (!IsSlider() && !IsSpinButton())
return;
float value;
if (!ValueForRange(&value))
return;
if (!RuntimeEnabledFeatures::
SynthesizedKeyboardEventsForAccessibilityActionsEnabled()) {
// If synthesized keyboard events are disabled, we need to set the value
// directly here.
// If no step was provided on the element, use a default value.
float step;
if (!StepValueForRange(&step)) {
if (IsNativeSlider() || IsNativeSpinButton()) {
step = StepRange().Step().ToString().ToFloat();
} else {
return;
}
}
value += increase ? step : -step;
if (native_role_ == ax::mojom::blink::Role::kSlider ||
native_role_ == ax::mojom::blink::Role::kSpinButton) {
OnNativeSetValueAction(String::Number(value));
// Dispatching an event could result in changes to the document, like
// this AXObject becoming detached.
if (IsDetached())
return;
AXObjectCache().HandleValueChanged(GetNode());
return;
}
}
// If we have synthesized keyboard events enabled, we generate a keydown
// event:
// * For a native slider, the dispatch of the event will reach
// RangeInputType::HandleKeydownEvent(), where the value will be set and the
// AXObjectCache notified. The corresponding keydown/up JS events will be
// fired so the website doesn't know it was produced by an AT action.
// * For an ARIA slider, the corresponding keydown/up JS events will be
// fired. It is expected that the handlers for those events manage the
// update of the slider value.
AXAction action =
increase ? AXAction::kActionIncrement : AXAction::kActionDecrement;
LocalDOMWindow* local_dom_window = GetDocument()->domWindow();
AccessibilityOrientation orientation = Orientation();
ax::mojom::blink::WritingDirection text_direction = GetTextDirection();
// A kKeyDown event is kRawKeyDown + kChar events. We cannot synthesize it
// because the KeyboardEvent constructor will prevent it, to force us to
// decide if we must produce both events. In our case, we don't have to
// produce a kChar event because we are synthesizing arrow key presses, and
// only keys that output characters are expected to produce kChar events.
KeyboardEvent* keydown =
CreateKeyboardEvent(local_dom_window, WebInputEvent::Type::kRawKeyDown,
action, orientation, text_direction);
GetNode()->DispatchEvent(*keydown);
// The keydown handler may have caused the node to be removed.
if (!GetNode())
return;
KeyboardEvent* keyup =
CreateKeyboardEvent(local_dom_window, WebInputEvent::Type::kKeyUp, action,
orientation, text_direction);
// Add a 100ms delay between keydown and keyup to make events look less
// evidently synthesized.
GetDocument()
->GetTaskRunner(TaskType::kUserInteraction)
->PostDelayedTask(
FROM_HERE,
BindOnce(
[](Node* node, KeyboardEvent* evt) {
if (node) {
node->DispatchEvent(*evt);
}
},
WrapWeakPersistent(GetNode()), WrapPersistent(keyup)),
base::Milliseconds(100));
}
AXObject* AXNodeObject::ActiveDescendant() const {
Element* element = GetElement();
if (!element)
return nullptr;
if (RoleValue() == ax::mojom::blink::Role::kMenuListPopup) {
if (HTMLSelectElement* select =
DynamicTo<HTMLSelectElement>(parent_->GetNode())) {
// TODO(accessibility): as a simplification, just expose the active
// descendant of a <select size=1> at all times, like we do for other
// active descendant situations,
return select->PopupIsVisible() || select->IsFocusedElementInDocument()
? AXObjectCache().Get(select->OptionToBeShown())
: nullptr;
}
}
if (auto* select = DynamicTo<HTMLSelectElement>(GetNode())) {
if (!select->UsesMenuList()) {
return AXObjectCache().Get(select->ActiveSelectionEnd());
}
}
const Element* descendant = ElementFromAttributeOrInternals(
element, html_names::kAriaActivedescendantAttr);
if (!descendant) {
return nullptr;
}
AXObject* ax_descendant = AXObjectCache().Get(descendant);
return ax_descendant && ax_descendant->IsVisible() ? ax_descendant : nullptr;
}
bool IsExemptFromInlineBlockCheck(ax::mojom::blink::Role role) {
return role == ax::mojom::blink::Role::kSvgRoot ||
role == ax::mojom::blink::Role::kCanvas ||
role == ax::mojom::blink::Role::kEmbeddedObject;
}
bool AXNodeObject::HasCustomElementTreeProcessing() const {
if (!RuntimeEnabledFeatures::AccessibilityCustomElementRoleNoneEnabled()) {
return false;
}
if (!GetElement()) {
return false;
}
if (!GetElement()->IsCustomElement()) {
return false;
}
return true;
}
bool AXNodeObject::ShouldIncludeCustomElement() const {
Element* element = GetElement();
DCHECK(element);
DCHECK(element->IsCustomElement()) << element;
// Check whether author has forced it to be ignored via role="none".
if (RoleValue() == ax::mojom::blink::Role::kNone) {
return false;
}
// Custom elements are ignored in the tree by default, with some exceptions:
// * Has implicit or explicit (role attribute) role.
if (RoleValue() != ax::mojom::blink::Role::kGenericContainer) {
return true;
}
//* No shadow root attached.
if (!element->GetShadowRoot()) {
return true;
}
// * Has aria-live. This is a legitimate use case for ARIA semantics on
// a custom element.
if (HasAriaAttribute(html_names::kAriaLiveAttr)) {
return true;
}
// * Uses element internals with an accessibility attribute set.
// As element internals are not a convenient way to declare semantics, this
// indicates that it is more about hiding an implementation of semantics on
// the custom element, they are not likely to be used for semantics that
// are to be passed down into the shadow subtree by copying.
if (element->GetElementInternals() &&
element->GetElementInternals()->HasAnyAttribute()) {
return true;
}
// * Focusable.
if (element->IsKeyboardFocusableSlow(
Element::UpdateBehavior::kNoneForAccessibility)) {
return true;
}
// * <webview> (special deprecated element used in ChromeOS WebUI apps, and
// kept in tree to pass AutomationApiTest.LocationInWebView).
// Custom elements in actual web content always have a hyphenated name,
// and therefore <webview> in real web content cannot be a custom element.
DEFINE_STATIC_LOCAL(const AtomicString, web_view_tag, ("webview"));
if (element->HasLocalName(web_view_tag)) {
return true;
}
return false;
}
AXObjectInclusion AXNodeObject::ShouldIncludeBasedOnSemantics(
IgnoredReasons* ignored_reasons) const {
DCHECK(GetDocument());
// All nodes must have an unignored parent within their tree under
// the root node of the web area, so force that node to always be unignored.
if (IsA<Document>(GetNode())) {
return kIncludeObject;
}
if (IsPresentational()) {
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXPresentational));
return kIgnoreObject;
}
Node* node = GetNode();
if (!node) {
// Nodeless pseudo-element images are included, even if they don't have CSS
// alt text. This can allow auto alt to be applied to them.
if (IsImage())
return kIncludeObject;
return kDefaultBehavior;
}
// Include carousel controls.
if (node->IsScrollMarkerGroupPseudoElement() ||
node->IsScrollMarkerPseudoElement() ||
node->IsScrollButtonPseudoElement()) {
return kIncludeObject;
}
// Avoid double speech. The ruby text describes pronunciation of the ruby
// base, and generally produces redundant screen reader output. Expose it only
// as a description on the <ruby> element so that screen reader users can
// toggle it on/off as with other descriptions/annotations.
if (RoleValue() == ax::mojom::blink::Role::kRubyAnnotation ||
(RoleValue() == ax::mojom::blink::Role::kStaticText && ParentObject() &&
ParentObject()->RoleValue() ==
ax::mojom::blink::Role::kRubyAnnotation)) {
return kIgnoreObject;
}
Element* element = GetElement();
if (!element) {
return kDefaultBehavior;
}
if (IsExcludedByFormControlsFilter()) {
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXUninteresting));
}
return kIgnoreObject;
}
if (IsA<SVGElement>(node)) {
// The symbol element is used to define graphical templates which can be
// instantiated by a use element but which are not rendered directly. We
// don't want to include these template objects, or their subtrees, where
// they appear in the DOM. Any associated semantic information (e.g. the
// title child of a symbol) may participate in the text alternative
// computation where it is instantiated by the use element.
// https://svgwg.org/svg2-draft/struct.html#SymbolElement
if (Traversal<SVGSymbolElement>::FirstAncestorOrSelf(*node))
return kIgnoreObject;
// Include non-empty SVG root as clients may want to treat it as an image.
if (IsA<SVGSVGElement>(node) && GetLayoutObject() &&
GetLayoutObject()->IsSVGRoot() && element->firstElementChild()) {
return kIncludeObject;
}
// The SVG-AAM states that user agents MUST provide an accessible object
// for rendered SVG elements that have at least one direct child title or
// desc element that is not empty after trimming whitespace. But it also
// says, "User agents MAY include elements with these child elements without
// checking for valid text content." So just check for their existence in
// order to be performant. https://w3c.github.io/svg-aam/#include_elements
if (ElementTraversal::FirstChild(
*To<ContainerNode>(node), [](auto& element) {
return element.HasTagName(svg_names::kTitleTag) ||
element.HasTagName(svg_names::kDescTag);
})) {
return kIncludeObject;
}
// If setting enabled, do not ignore SVG grouping (<g>) elements.
if (IsA<SVGGElement>(node)) {
Settings* settings = GetDocument()->GetSettings();
if (settings->GetAccessibilityIncludeSvgGElement()) {
return kIncludeObject;
}
}
// If we return kDefaultBehavior here, the logic related to inclusion of
// clickable objects, links, controls, etc. will not be reached. We handle
// SVG elements early to ensure properties in a <symbol> subtree do not
// result in inclusion.
}
if (IsTableLikeRole() || IsTableRowLikeRole() || IsTableCellLikeRole() ||
element->HasTagName(html_names::kTheadTag) ||
element->HasTagName(html_names::kTfootTag)) {
return kIncludeObject;
}
if (IsA<HTMLHtmlElement>(node)) {
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXUninteresting));
}
return kIgnoreObject;
}
// All focusable elements except the <body> and <html> are included.
if (!IsA<HTMLBodyElement>(node) && CanSetFocusAttribute())
return kIncludeObject;
if (IsLink())
return kIncludeObject;
// A click handler might be placed on an otherwise ignored non-empty block
// element, e.g. a div. We shouldn't ignore such elements because if an AT
// sees the |ax::mojom::blink::DefaultActionVerb::kClickAncestor|, it will
// look for the clickable ancestor and it expects to find one.
if (IsClickable())
return kIncludeObject;
if (IsHeading())
return kIncludeObject;
// Header and footer tags may also be exposed as landmark roles but not
// always.
if (node->HasTagName(html_names::kHeaderTag) ||
node->HasTagName(html_names::kFooterTag))
return kIncludeObject;
// All controls are accessible.
if (IsControl())
return kIncludeObject;
if (IsA<HTMLOptGroupElement>(node)) {
return kIncludeObject;
}
// Anything with an explicit ARIA role should be included.
if (RawAriaRole() != ax::mojom::blink::Role::kUnknown) {
return kIncludeObject;
}
// Anything that is an editable root should not be ignored. However, one
// cannot just call `AXObject::IsEditable()` since that will include the
// contents of an editable region too. Only the editable root should always be
// exposed.
if (IsEditableRoot())
return kIncludeObject;
// Custom elements are generally ignored in the tree, with some exceptions.
if (HasCustomElementTreeProcessing()) {
return ShouldIncludeCustomElement() ? kIncludeObject : kIgnoreObject;
}
// Don't ignored legends, because JAWS uses them to determine redundant text.
if (IsA<HTMLLegendElement>(node)) {
// When a <legend> is used inside an <optgroup>, it is used to set the
// name of the <optgroup> and shouldn't be redundantly repeated.
for (auto* ancestor = node->parentNode(); ancestor;
ancestor = ancestor->parentNode()) {
if (IsA<HTMLOptGroupElement>(ancestor)) {
return kIgnoreObject;
}
}
return kIncludeObject;
}
static constexpr auto always_included_computed_roles =
base::MakeFixedFlatSet<ax::mojom::blink::Role>({
ax::mojom::blink::Role::kAbbr,
ax::mojom::blink::Role::kApplication,
ax::mojom::blink::Role::kArticle,
ax::mojom::blink::Role::kAudio,
ax::mojom::blink::Role::kBanner,
ax::mojom::blink::Role::kBlockquote,
ax::mojom::blink::Role::kCode,
ax::mojom::blink::Role::kComplementary,
ax::mojom::blink::Role::kContentDeletion,
ax::mojom::blink::Role::kContentInfo,
ax::mojom::blink::Role::kContentInsertion,
ax::mojom::blink::Role::kDefinition,
ax::mojom::blink::Role::kDescriptionList,
ax::mojom::blink::Role::kDetails,
ax::mojom::blink::Role::kDialog,
ax::mojom::blink::Role::kDocAcknowledgments,
ax::mojom::blink::Role::kDocAfterword,
ax::mojom::blink::Role::kDocAppendix,
ax::mojom::blink::Role::kDocBibliography,
ax::mojom::blink::Role::kDocChapter,
ax::mojom::blink::Role::kDocConclusion,
ax::mojom::blink::Role::kDocCredits,
ax::mojom::blink::Role::kDocEndnotes,
ax::mojom::blink::Role::kDocEpilogue,
ax::mojom::blink::Role::kDocErrata,
ax::mojom::blink::Role::kDocForeword,
ax::mojom::blink::Role::kDocGlossary,
ax::mojom::blink::Role::kDocIntroduction,
ax::mojom::blink::Role::kDocPart,
ax::mojom::blink::Role::kDocPreface,
ax::mojom::blink::Role::kDocPrologue,
ax::mojom::blink::Role::kDocToc,
ax::mojom::blink::Role::kEmphasis,
ax::mojom::blink::Role::kFigcaption,
ax::mojom::blink::Role::kFigure,
ax::mojom::blink::Role::kFooter,
ax::mojom::blink::Role::kForm,
ax::mojom::blink::Role::kHeader,
ax::mojom::blink::Role::kList,
ax::mojom::blink::Role::kListItem,
ax::mojom::blink::Role::kMain,
ax::mojom::blink::Role::kMark,
ax::mojom::blink::Role::kMath,
ax::mojom::blink::Role::kMathMLMath,
// Don't ignore MathML nodes by default, since MathML
// relies on child positions to determine semantics
// (e.g. numerator is the first child of a fraction).
ax::mojom::blink::Role::kMathMLFraction,
ax::mojom::blink::Role::kMathMLIdentifier,
ax::mojom::blink::Role::kMathMLMultiscripts,
ax::mojom::blink::Role::kMathMLNoneScript,
ax::mojom::blink::Role::kMathMLNumber,
ax::mojom::blink::Role::kMathMLOperator,
ax::mojom::blink::Role::kMathMLOver,
ax::mojom::blink::Role::kMathMLPrescriptDelimiter,
ax::mojom::blink::Role::kMathMLRoot,
ax::mojom::blink::Role::kMathMLRow,
ax::mojom::blink::Role::kMathMLSquareRoot,
ax::mojom::blink::Role::kMathMLStringLiteral,
ax::mojom::blink::Role::kMathMLSub,
ax::mojom::blink::Role::kMathMLSubSup,
ax::mojom::blink::Role::kMathMLSup,
ax::mojom::blink::Role::kMathMLTable,
ax::mojom::blink::Role::kMathMLTableCell,
ax::mojom::blink::Role::kMathMLTableRow,
ax::mojom::blink::Role::kMathMLText,
ax::mojom::blink::Role::kMathMLUnder,
ax::mojom::blink::Role::kMathMLUnderOver,
ax::mojom::blink::Role::kMeter,
ax::mojom::blink::Role::kMenuListOption,
ax::mojom::blink::Role::kMenuListPopup,
ax::mojom::blink::Role::kNavigation,
ax::mojom::blink::Role::kPluginObject,
ax::mojom::blink::Role::kProgressIndicator,
ax::mojom::blink::Role::kRegion,
ax::mojom::blink::Role::kRuby,
ax::mojom::blink::Role::kSearch,
ax::mojom::blink::Role::kSection,
ax::mojom::blink::Role::kSplitter,
ax::mojom::blink::Role::kSubscript,
ax::mojom::blink::Role::kSuperscript,
ax::mojom::blink::Role::kStrong,
ax::mojom::blink::Role::kTerm,
ax::mojom::blink::Role::kTime,
ax::mojom::blink::Role::kVideo,
});
if (base::Contains(always_included_computed_roles, RoleValue())) {
return kIncludeObject;
}
// An <hgroup> element has the "group" aria role.
if (GetNode()->HasTagName(html_names::kHgroupTag)) {
return kIncludeObject;
}
// Interesting ARIA properties are enough to cause objects to be included,
// unless the computed role is none. Note that global ARIA properties usually
// undo role=none (exception has been made for custom roles).
// See https://w3c.github.io/aria/#conflict_resolution_presentation_none
// for more details.
if (ElementHasAnyAriaAttribute()) {
return kIncludeObject;
}
// Using a title for a name or description causes an object to be included.
if (!GetElement()->FastGetAttribute(kTitleAttr).empty()) {
return kIncludeObject;
}
if (IsImage() && !IsA<SVGElement>(node)) {
String alt = GetElement()->FastGetAttribute(kAltAttr);
// A null alt attribute means the attribute is not present. We assume this
// is a mistake, and expose the image so that it can be repaired.
// In contrast, alt="" is treated as intentional markup to ignore the image.
if (!alt.empty() || alt.IsNull())
return kIncludeObject;
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXEmptyAlt));
return kIgnoreObject;
}
// Process potential in-page link targets
if (IsPotentialInPageLinkTarget(*element))
return kIncludeObject;
if (AXObjectCache().GetAXMode().has_mode(ui::AXMode::kInlineTextBoxes)) {
// We are including inline block elements since we might rely on these for
// NextOnLine/PreviousOnLine computations.
//
// If we have an element with inline
// block specified, we should include. There are some roles where we
// shouldn't include even if inline block, or we'll get test failures.
//
// We also only want to include in the tree if the inline block element has
// siblings.
// Otherwise we will include nodes that we don't need for anything.
// Consider a structure where we have a subtree of 12 layers, where each
// layer has an inline-block node with a single child that points to the
// next layer. All nodes have a single child, meaning that this child has no
// siblings.
if (!IsExemptFromInlineBlockCheck(native_role_) && GetLayoutObject() &&
GetLayoutObject()->IsInline() &&
GetLayoutObject()->IsAtomicInlineLevel() &&
node->parentNode()->childElementCount() > 1) {
return kIncludeObject;
}
}
// Anything with non empty CSS alt should be included.
// https://drafts.csswg.org/css-content/#alt
// Descendants are pruned: IsRelevantPseudoElementDescendant() returns false.
std::optional<String> alt_text = GetCSSAltText(GetElement());
if (alt_text) {
if (alt_text->empty()) {
return kIgnoreObject;
} else {
return kIncludeObject;
}
}
// <span> tags are inline tags and not meant to convey information if they
// have no other ARIA information on them. If we don't ignore them, they may
// emit signals expected to come from their parent.
if (IsA<HTMLSpanElement>(node)) {
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXUninteresting));
return kIgnoreObject;
}
// Ignore labels that are already used to name a control.
// See IsRedundantLabel() for more commentary.
if (HTMLLabelElement* label = DynamicTo<HTMLLabelElement>(node)) {
if (IsRedundantLabel(label)) {
if (ignored_reasons) {
ignored_reasons->push_back(
IgnoredReason(kAXLabelFor, AXObjectCache().Get(label->Control())));
}
return kIgnoreObject;
}
return kIncludeObject;
}
// The SVG-AAM says the foreignObject element is normally presentational.
if (IsA<SVGForeignObjectElement>(node)) {
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXPresentational));
}
return kIgnoreObject;
}
return kDefaultBehavior;
}
bool AXNodeObject::ComputeIsIgnored(IgnoredReasons* ignored_reasons) const {
Node* node = GetNode();
// Originating element should be ignored in AX tree, if the ::scroll-marker
// is in tabs mode and not active.
if (RuntimeEnabledFeatures::CSSScrollMarkerGroupModesEnabled() &&
IsOriginatingElementForInactiveScrollMarkerInTabsMode(node)) {
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXInactiveCarouselTabContent));
}
return true;
}
if (ShouldIgnoreForHiddenOrInert(ignored_reasons)) {
if (IsAriaHidden()) {
return true;
}
// Keep structure of <select size=1> even when collapsed.
if (const AXObject* ax_menu_list = ParentObject()->AncestorMenuList()) {
// The author provided <button> is marked as inert so it falls into this
// case. We want it and all of its descendants to be ignored. If any of
// them aren't ignored, then they will make it into the mappings. The
// button can't be pruned from the tree because it is used to compute the
// value of the MenuList.
for (const AXObject* ancestor = this;
ancestor && ancestor != ax_menu_list;
ancestor = ancestor->ParentObject()) {
if (HTMLSelectElement::IsSlottedButton(ancestor->GetNode())) {
return true;
}
}
return ax_menu_list->IsIgnored();
}
// Fallback elements inside of a <canvas> are invisible, but are not ignored
if (IsHiddenViaStyle() || !node || !node->ParentOrShadowHostElement() ||
!node->ParentOrShadowHostElement()->IsCanvasOrInCanvasSubtree()) {
return true;
}
}
// Handle content that is either visible or in a canvas subtree.
AXObjectInclusion include = ShouldIncludeBasedOnSemantics(ignored_reasons);
if (include == kIncludeObject) {
return false;
}
if (include == kIgnoreObject) {
return true;
}
if (!GetLayoutObject()) {
// Text without a layout object that has reached this point is not
// explicitly hidden, e.g. is in a <canvas> fallback or is display locked.
if (IsA<Text>(node)) {
return false;
}
// Similarly, elements in <canvas> fallback should not be ignored.
if (node->ParentOrShadowHostElement() &&
node->ParentOrShadowHostElement()->IsCanvasOrInCanvasSubtree()) {
// TODO: We should not exclude display: contents (crbug.com/41384724) in
// canvas.
if (!GetElement() || !GetElement()->HasDisplayContentsStyle()) {
return false;
}
}
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXUninteresting));
}
return true;
}
// Inner editor element of editable area with empty text provides bounds
// used to compute the character extent for index 0. This is the same as
// what the caret's bounds would be if the editable area is focused.
if (node) {
const TextControlElement* text_control = EnclosingTextControl(node);
if (text_control) {
// Keep only the inner editor element and it's children.
// If inline textboxes are being loaded, then the inline textbox for the
// text wil be included by AXNodeObject::AddInlineTextboxChildren().
// By only keeping the inner editor and its text, it makes finding the
// inner editor simpler on the browser side.
// See BrowserAccessibility::GetTextFieldInnerEditorElement().
// TODO(accessibility) In the future, we may want to keep all descendants
// of the inner text element -- right now we only include one internally
// used container, it's text, and possibly the text's inlinext text box.
return text_control->InnerEditorElement() != node &&
text_control->InnerEditorElement() != NodeTraversal::Parent(*node);
}
}
// A LayoutEmbeddedContent is an iframe element or embedded object element or
// something like that. We don't want to ignore those.
if (GetLayoutObject()->IsLayoutEmbeddedContent()) {
return false;
}
if (node && node->IsInUserAgentShadowRoot()) {
Element* host = node->OwnerShadowHost();
if (auto* containing_media_element = DynamicTo<HTMLMediaElement>(host)) {
if (!containing_media_element->ShouldShowControls()) {
return true;
}
}
if (IsA<HTMLOptGroupElement>(host)) {
return false;
}
}
if (IsCanvas()) {
if (CanvasHasFallbackContent()) {
return false;
}
// A 1x1 canvas is too small for the user to see and thus ignored.
const auto* canvas = DynamicTo<LayoutHTMLCanvas>(GetLayoutObject());
if (canvas) {
PhysicalSize size = canvas->StitchedSize();
if (size.height <= 1 || size.width <= 1) {
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXProbablyPresentational));
}
return true;
}
}
// Otherwise fall through; use presence of help text, title, or description
// to decide.
}
if (GetLayoutObject()->IsBR()) {
return false;
}
if (GetLayoutObject()->IsText()) {
if (GetLayoutObject()->IsInListMarker()) {
// Ignore TextAlternative of the list marker for SUMMARY because:
// - TextAlternatives for disclosure-* are triangle symbol characters
// used to visually indicate the expansion state.
// - It's redundant. The host DETAILS exposes the expansion state.
// Also ignore text descendants of any non-ignored list marker because the
// text descendants do not provide any extra information than the
// TextAlternative on the list marker. Besides, with 'speak-as', they will
// be inconsistent with the list marker.
const AXObject* list_marker_object =
ContainerListMarkerIncludingIgnored();
if (list_marker_object &&
(list_marker_object->GetLayoutObject()->IsListMarkerForSummary() ||
!list_marker_object->IsIgnored())) {
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXPresentational));
}
return true;
}
}
// Ignore text inside of an ignored <label>.
// To save processing, only walk up the ignored objects.
// This means that other interesting objects inside the <label> will
// cause the text to be unignored.
if (IsUsedForLabelOrDescription()) {
const AXObject* ancestor = ParentObject();
while (ancestor && ancestor->IsIgnored()) {
if (ancestor->RoleValue() == ax::mojom::blink::Role::kLabelText) {
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXPresentational));
}
return true;
}
ancestor = ancestor->ParentObject();
}
}
return false;
}
if (GetLayoutObject()->IsListMarker()) {
// Ignore TextAlternative of the list marker for SUMMARY because:
// - TextAlternatives for disclosure-* are triangle symbol characters used
// to visually indicate the expansion state.
// - It's redundant. The host DETAILS exposes the expansion state.
if (GetLayoutObject()->IsListMarkerForSummary()) {
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXPresentational));
}
return true;
}
return false;
}
// Positioned elements and scrollable containers are important for determining
// bounding boxes, so don't ignore them unless they are pseudo-content.
if (!GetLayoutObject()->IsPseudoElement()) {
if (IsScrollableContainer()) {
return false;
}
if (GetLayoutObject()->IsPositioned()) {
return false;
}
}
// Ignore a block flow (display:block, display:inline-block), unless it
// directly parents inline children.
// This effectively trims a lot of uninteresting divs out of the tree.
if (auto* block_flow = DynamicTo<LayoutBlockFlow>(GetLayoutObject())) {
if (block_flow->ChildrenInline() && block_flow->FirstChild()) {
return false;
}
}
// By default, objects should be ignored so that the AX hierarchy is not
// filled with unnecessary items.
if (ignored_reasons) {
ignored_reasons->push_back(IgnoredReason(kAXUninteresting));
}
return true;
}
// static
std::optional<String> AXNodeObject::GetCSSAltText(const Element* element) {
// CSS alt text rules allow text to be assigned to ::before/::after content.
// For example, the following CSS assigns "bullet" text to bullet.png:
// .something::before {
// content: url(bullet.png) / "bullet";
// }
if (!element) {
return std::nullopt;
}
const ComputedStyle* style = element->GetComputedStyle();
if (!style || style->ContentBehavesAsNormal()) {
return std::nullopt;
}
if (element->IsPseudoElement()) {
for (const ContentData* content_data = style->GetContentData();
content_data; content_data = content_data->Next()) {
if (content_data->IsAlt()) {
return ContentData::ConcatenateAltText(*content_data);
}
}
return std::nullopt;
}
// If the content property is used on a non-pseudo-element, match the
// behaviour of LayoutObject::CreateObject and only honour the style if
// there is exactly one piece of content, which is an image.
const ContentData* content_data = style->GetContentData();
if (content_data && content_data->IsImage() && content_data->Next() &&
content_data->Next()->IsAlt()) {
return ContentData::ConcatenateAltText(*content_data->Next());
}
return std::nullopt;
}
std::optional<String> AXNodeObject::GetCSSContentText(const Element* element) {
if (!element || !element->IsPseudoElement() || !element->GetLayoutObject()) {
return std::nullopt;
}
StringBuilder builder;
CollectLayoutTextContentRecursive(builder, element->GetLayoutObject());
return builder.ToString();
}
// The following lists are for deciding whether the tags aside,
// header and footer can be interpreted as roles complementary, banner and
// contentInfo or if they should be interpreted as generic, sectionheader, or
// sectionfooter.
// This function only handles the complementary, banner, and contentInfo roles,
// which belong to the landmark roles set.
static HashSet<ax::mojom::blink::Role>& GetLandmarkIsNotAllowedAncestorRoles(
ax::mojom::blink::Role landmark) {
// clang-format off
DEFINE_STATIC_LOCAL(
// https://html.spec.whatwg.org/multipage/dom.html#sectioning-content-2
// The aside element should not assume the complementary role when nested
// within the following sectioning content elements.
HashSet<ax::mojom::blink::Role>, complementary_is_not_allowed_roles,
({
ax::mojom::blink::Role::kArticle,
ax::mojom::blink::Role::kComplementary,
ax::mojom::blink::Role::kNavigation,
ax::mojom::blink::Role::kSection
}));
// https://w3c.github.io/html-aam/#el-header-ancestorbody
// The header and footer elements should not assume the banner and
// contentInfo roles, respectively, when nested within any of the
// sectioning content elements or the main element.
DEFINE_STATIC_LOCAL(
HashSet<ax::mojom::blink::Role>, landmark_is_not_allowed_roles,
({
ax::mojom::blink::Role::kArticle,
ax::mojom::blink::Role::kComplementary,
ax::mojom::blink::Role::kMain,
ax::mojom::blink::Role::kNavigation,
ax::mojom::blink::Role::kSection
}));
// clang-format on
if (landmark == ax::mojom::blink::Role::kComplementary) {
return complementary_is_not_allowed_roles;
}
return landmark_is_not_allowed_roles;
}
bool AXNodeObject::IsDescendantOfLandmarkDisallowedElement() const {
if (!GetNode())
return false;
auto role_names = GetLandmarkIsNotAllowedAncestorRoles(RoleValue());
for (AXObject* parent = ParentObjectUnignored(); parent;
parent = parent->ParentObjectUnignored()) {
if (role_names.Contains(parent->RoleValue())) {
return true;
}
}
return false;
}
static bool IsNonEmptyNonHeaderCell(const Node* cell) {
return cell && cell->hasChildren() && cell->HasTagName(html_names::kTdTag);
}
static bool IsHeaderCell(const Node* cell) {
return cell && cell->HasTagName(html_names::kThTag);
}
static ax::mojom::blink::Role DecideRoleFromSiblings(Element* cell) {
// If this header is only cell in its row, it is a column header.
// It is also a column header if it has a header on either side of it.
// If instead it has a non-empty td element next to it, it is a row header.
const Node* next_cell = LayoutTreeBuilderTraversal::NextSibling(*cell);
const Node* previous_cell =
LayoutTreeBuilderTraversal::PreviousSibling(*cell);
if (!next_cell && !previous_cell)
return ax::mojom::blink::Role::kColumnHeader;
if (IsHeaderCell(next_cell) && IsHeaderCell(previous_cell))
return ax::mojom::blink::Role::kColumnHeader;
if (IsNonEmptyNonHeaderCell(next_cell) ||
IsNonEmptyNonHeaderCell(previous_cell))
return ax::mojom::blink::Role::kRowHeader;
const auto* row = DynamicTo<HTMLTableRowElement>(cell->parentNode());
if (!row)
return ax::mojom::blink::Role::kColumnHeader;
// If this row's first or last cell is a non-empty td, this is a row header.
// Do the same check for the second and second-to-last cells because tables
// often have an empty cell at the intersection of the row and column headers.
const Element* first_cell = ElementTraversal::FirstChild(*row);
DCHECK(first_cell);
const Element* last_cell = ElementTraversal::LastChild(*row);
DCHECK(last_cell);
if (IsNonEmptyNonHeaderCell(first_cell) || IsNonEmptyNonHeaderCell(last_cell))
return ax::mojom::blink::Role::kRowHeader;
if (IsNonEmptyNonHeaderCell(ElementTraversal::NextSibling(*first_cell)) ||
IsNonEmptyNonHeaderCell(ElementTraversal::PreviousSibling(*last_cell)))
return ax::mojom::blink::Role::kRowHeader;
// We have no evidence that this is not a column header.
return ax::mojom::blink::Role::kColumnHeader;
}
ax::mojom::blink::Role AXNodeObject::DetermineTableSectionRole() const {
if (!GetElement())
return ax::mojom::blink::Role::kGenericContainer;
AXObject* parent = GetDOMTableAXAncestor(GetNode(), AXObjectCache());
if (!parent || !parent->IsTableLikeRole())
return ax::mojom::blink::Role::kGenericContainer;
if (parent->RoleValue() == ax::mojom::blink::Role::kLayoutTable)
return ax::mojom::blink::Role::kGenericContainer;
return ax::mojom::blink::Role::kRowGroup;
}
ax::mojom::blink::Role AXNodeObject::DetermineTableRowRole() const {
AXObject* parent = GetDOMTableAXAncestor(GetNode(), AXObjectCache());
if (!parent || !parent->IsTableLikeRole())
return ax::mojom::blink::Role::kGenericContainer;
if (parent->RoleValue() == ax::mojom::blink::Role::kLayoutTable)
return ax::mojom::blink::Role::kLayoutTableRow;
return ax::mojom::blink::Role::kRow;
}
ax::mojom::blink::Role AXNodeObject::DetermineTableCellRole() const {
AXObject* parent = GetDOMTableAXAncestor(GetNode(), AXObjectCache());
if (!parent || !parent->IsTableRowLikeRole())
return ax::mojom::blink::Role::kGenericContainer;
// Ensure table container.
AXObject* grandparent =
GetDOMTableAXAncestor(parent->GetNode(), AXObjectCache());
if (!grandparent || !grandparent->IsTableLikeRole())
return ax::mojom::blink::Role::kGenericContainer;
if (parent->RoleValue() == ax::mojom::blink::Role::kLayoutTableRow)
return ax::mojom::blink::Role::kLayoutTableCell;
if (!GetElement() || !GetNode()->HasTagName(html_names::kThTag))
return ax::mojom::blink::Role::kCell;
const AtomicString& scope =
GetElement()->FastGetAttribute(html_names::kScopeAttr);
if (EqualIgnoringASCIICase(scope, "row") ||
EqualIgnoringASCIICase(scope, "rowgroup"))
return ax::mojom::blink::Role::kRowHeader;
if (EqualIgnoringASCIICase(scope, "col") ||
EqualIgnoringASCIICase(scope, "colgroup"))
return ax::mojom::blink::Role::kColumnHeader;
return DecideRoleFromSiblings(GetElement());
}
unsigned AXNodeObject::ColumnCount() const {
if (RawAriaRole() != ax::mojom::blink::Role::kUnknown) {
return AXObject::ColumnCount();
}
if (const auto* table = DynamicTo<LayoutTable>(GetLayoutObject())) {
return table->EffectiveColumnCount();
}
return AXObject::ColumnCount();
}
unsigned AXNodeObject::RowCount() const {
if (RawAriaRole() != ax::mojom::blink::Role::kUnknown) {
return AXObject::RowCount();
}
LayoutTable* table;
auto* table_section = FirstTableSection(GetLayoutObject(), &table);
if (!table_section) {
return AXObject::RowCount();
}
unsigned row_count = 0;
while (table_section) {
row_count += table_section->NumRows();
table_section = table->NextSection(table_section);
}
return row_count;
}
unsigned AXNodeObject::ColumnIndex() const {
auto* cell = DynamicTo<LayoutTableCell>(GetLayoutObject());
if (cell && cell->GetNode()) {
return cell->Table()->AbsoluteColumnToEffectiveColumn(
cell->AbsoluteColumnIndex());
}
return AXObject::ColumnIndex();
}
unsigned AXNodeObject::RowIndex() const {
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->GetNode()) {
return AXObject::RowIndex();
}
unsigned row_index = 0;
const LayoutTableSection* row_section = nullptr;
const LayoutTable* table = nullptr;
if (const auto* row = DynamicTo<LayoutTableRow>(layout_object)) {
row_index = row->RowIndex();
row_section = row->Section();
table = row->Table();
} else if (const auto* cell = DynamicTo<LayoutTableCell>(layout_object)) {
row_index = cell->RowIndex();
row_section = cell->Section();
table = cell->Table();
} else {
return AXObject::RowIndex();
}
if (!table || !row_section) {
return AXObject::RowIndex();
}
// Since our table might have multiple sections, we have to offset our row
// appropriately.
const LayoutTableSection* section = table->FirstSection();
while (section && section != row_section) {
row_index += section->NumRows();
section = table->NextSection(section);
}
return row_index;
}
unsigned AXNodeObject::ColumnSpan() const {
auto* cell = DynamicTo<LayoutTableCell>(GetLayoutObject());
if (!cell) {
return AXObject::ColumnSpan();
}
LayoutTable* table = cell->Table();
unsigned absolute_first_col = cell->AbsoluteColumnIndex();
unsigned absolute_last_col = absolute_first_col + cell->ColSpan() - 1;
unsigned effective_first_col =
table->AbsoluteColumnToEffectiveColumn(absolute_first_col);
unsigned effective_last_col =
table->AbsoluteColumnToEffectiveColumn(absolute_last_col);
return effective_last_col - effective_first_col + 1;
}
unsigned AXNodeObject::RowSpan() const {
auto* cell = DynamicTo<LayoutTableCell>(GetLayoutObject());
return cell ? cell->ResolvedRowSpan() : AXObject::RowSpan();
}
ax::mojom::blink::SortDirection AXNodeObject::GetSortDirection() const {
if (RoleValue() != ax::mojom::blink::Role::kRowHeader &&
RoleValue() != ax::mojom::blink::Role::kColumnHeader) {
return ax::mojom::blink::SortDirection::kNone;
}
if (const AtomicString& aria_sort =
AriaTokenAttribute(html_names::kAriaSortAttr)) {
if (EqualIgnoringASCIICase(aria_sort, "none")) {
return ax::mojom::blink::SortDirection::kNone;
}
if (EqualIgnoringASCIICase(aria_sort, "ascending")) {
return ax::mojom::blink::SortDirection::kAscending;
}
if (EqualIgnoringASCIICase(aria_sort, "descending")) {
return ax::mojom::blink::SortDirection::kDescending;
}
// Technically, illegal values should be exposed as is, but this does
// not seem to be worth the implementation effort at this time.
return ax::mojom::blink::SortDirection::kOther;
}
return ax::mojom::blink::SortDirection::kNone;
}
AXObject* AXNodeObject::CellForColumnAndRow(unsigned target_column_index,
unsigned target_row_index) const {
LayoutTable* table;
auto* table_section = FirstTableSection(GetLayoutObject(), &table);
if (!table_section) {
return AXObject::CellForColumnAndRow(target_column_index, target_row_index);
}
unsigned row_offset = 0;
while (table_section) {
// Iterate backwards through the rows in case the desired cell has a rowspan
// and exists in a previous row.
for (LayoutTableRow* row = table_section->LastRow(); row;
row = row->PreviousRow()) {
unsigned row_index = row->RowIndex() + row_offset;
for (LayoutTableCell* cell = row->LastCell(); cell;
cell = cell->PreviousCell()) {
unsigned absolute_first_col = cell->AbsoluteColumnIndex();
unsigned absolute_last_col = absolute_first_col + cell->ColSpan() - 1;
unsigned effective_first_col =
table->AbsoluteColumnToEffectiveColumn(absolute_first_col);
unsigned effective_last_col =
table->AbsoluteColumnToEffectiveColumn(absolute_last_col);
unsigned row_span = cell->ResolvedRowSpan();
if (target_column_index >= effective_first_col &&
target_column_index <= effective_last_col &&
target_row_index >= row_index &&
target_row_index < row_index + row_span) {
return AXObjectCache().Get(cell);
}
}
}
row_offset += table_section->NumRows();
table_section = table->NextSection(table_section);
}
return nullptr;
}
bool AXNodeObject::FindAllTableCellsWithRole(ax::mojom::blink::Role role,
AXObjectVector& cells) const {
LayoutTable* table;
auto* table_section = FirstTableSection(GetLayoutObject(), &table);
if (!table_section) {
return false;
}
while (table_section) {
for (LayoutTableRow* row = table_section->FirstRow(); row;
row = row->NextRow()) {
for (LayoutTableCell* cell = row->FirstCell(); cell;
cell = cell->NextCell()) {
AXObject* ax_cell = AXObjectCache().Get(cell);
if (ax_cell && ax_cell->RoleValue() == role) {
cells.push_back(ax_cell);
}
}
}
table_section = table->NextSection(table_section);
}
return true;
}
void AXNodeObject::ColumnHeaders(AXObjectVector& headers) const {
if (!FindAllTableCellsWithRole(ax::mojom::blink::Role::kColumnHeader,
headers)) {
AXObject::ColumnHeaders(headers);
}
}
void AXNodeObject::RowHeaders(AXObjectVector& headers) const {
if (!FindAllTableCellsWithRole(ax::mojom::blink::Role::kRowHeader, headers)) {
AXObject::RowHeaders(headers);
}
}
AXObject* AXNodeObject::HeaderObject() const {
auto* row = DynamicTo<LayoutTableRow>(GetLayoutObject());
if (!row) {
return nullptr;
}
for (LayoutTableCell* cell = row->FirstCell(); cell;
cell = cell->NextCell()) {
AXObject* ax_cell = cell ? AXObjectCache().Get(cell) : nullptr;
if (ax_cell && ax_cell->RoleValue() == ax::mojom::blink::Role::kRowHeader) {
return ax_cell;
}
}
return nullptr;
}
// The following is a heuristic used to determine if a
// <table> should be with ax::mojom::blink::Role::kTable or
// ax::mojom::blink::Role::kLayoutTable.
// Only "data" tables should be exposed as tables.
// Unfortunately, there is no determinsistic or precise way to differentiate a
// layout table vs a data table. Fortunately, CSS authoring techniques have
// improved a lot and mostly supplanted the practice of using tables for layout.
bool AXNodeObject::IsDataTable() const {
DCHECK(!IsDetached());
auto* table_element = DynamicTo<HTMLTableElement>(GetNode());
if (!table_element) {
return false;
}
if (!GetLayoutObject()) {
// The table is not rendered, so the author has no reason to use the table
// for layout. Treat as a data table by default as there is not enough
// information to decide otherwise.
// One useful result of this is that a table inside a canvas fallback is
// treated as a data table.
return true;
}
// If it has an ARIA role, it's definitely a data table.
if (HasAriaAttribute(html_names::kRoleAttr)) {
return true;
}
// When a section of the document is contentEditable, all tables should be
// treated as data tables, otherwise users may not be able to work with rich
// text editors that allow creating and editing tables.
if (GetNode() && blink::IsEditable(*GetNode())) {
return true;
}
// If there is a caption element, summary, THEAD, or TFOOT section, it's most
// certainly a data table
if (!table_element->Summary().empty() || table_element->tHead() ||
table_element->tFoot() || table_element->caption()) {
return true;
}
// if someone used "rules" attribute than the table should appear
if (!table_element->Rules().empty()) {
return true;
}
// if there's a colgroup or col element, it's probably a data table.
if (Traversal<HTMLTableColElement>::FirstChild(*table_element)) {
return true;
}
// If there are at least 20 rows, we'll call it a data table.
HTMLTableRowsCollection* rows = table_element->rows();
int num_rows = rows->length();
if (num_rows >= AXObjectCacheImpl::kDataTableHeuristicMinRows) {
return true;
}
if (num_rows <= 0) {
return false;
}
int num_cols_in_first_body = rows->Item(0)->cells()->length();
// If there's only one cell, it's not a good AXTable candidate.
if (num_rows == 1 && num_cols_in_first_body == 1) {
return false;
}
// Store the background color of the table to check against cell's background
// colors.
const ComputedStyle* table_style = GetLayoutObject()->Style();
if (!table_style) {
return false;
}
Color table_bg_color =
table_style->VisitedDependentColor(GetCSSPropertyBackgroundColor());
bool has_cell_spacing = table_style->HorizontalBorderSpacing() &&
table_style->VerticalBorderSpacing();
// check enough of the cells to find if the table matches our criteria
// Criteria:
// 1) must have at least one valid cell (and)
// 2) at least half of cells have borders (or)
// 3) at least half of cells have different bg colors than the table, and
// there is cell spacing
unsigned valid_cell_count = 0;
unsigned bordered_cell_count = 0;
unsigned background_difference_cell_count = 0;
unsigned cells_with_top_border = 0;
unsigned cells_with_bottom_border = 0;
unsigned cells_with_left_border = 0;
unsigned cells_with_right_border = 0;
std::array<Color, 5> alternating_row_colors;
int alternating_row_color_count = 0;
for (int row = 0; row < num_rows; ++row) {
HTMLTableRowElement* row_element = rows->Item(row);
int n_cols = row_element->cells()->length();
for (int col = 0; col < n_cols; ++col) {
const Element* cell = row_element->cells()->item(col);
if (!cell) {
continue;
}
// Any <th> tag -> treat as data table.
if (cell->HasTagName(html_names::kThTag)) {
return true;
}
// Check for an explicitly assigned a "data" table attribute.
auto* cell_elem = DynamicTo<HTMLTableCellElement>(*cell);
if (cell_elem) {
if (!cell_elem->Headers().empty() || !cell_elem->Abbr().empty() ||
!cell_elem->Axis().empty() ||
!cell_elem->FastGetAttribute(html_names::kScopeAttr).empty()) {
return true;
}
}
LayoutObject* cell_layout_object = cell->GetLayoutObject();
if (!cell_layout_object || !cell_layout_object->IsLayoutBlock()) {
continue;
}
const LayoutBlock* cell_layout_block =
To<LayoutBlock>(cell_layout_object);
PhysicalSize size = cell_layout_block->StitchedSize();
if (size.width < 1 || size.height < 1) {
continue;
}
valid_cell_count++;
const ComputedStyle* computed_style = cell_layout_block->Style();
if (!computed_style) {
continue;
}
// If the empty-cells style is set, we'll call it a data table.
if (computed_style->EmptyCells() == EEmptyCells::kHide) {
return true;
}
// If a cell has matching bordered sides, call it a (fully) bordered cell.
if ((cell_layout_block->BorderTop() > 0 &&
cell_layout_block->BorderBottom() > 0) ||
(cell_layout_block->BorderLeft() > 0 &&
cell_layout_block->BorderRight() > 0)) {
bordered_cell_count++;
}
// Also keep track of each individual border, so we can catch tables where
// most cells have a bottom border, for example.
if (cell_layout_block->BorderTop() > 0) {
cells_with_top_border++;
}
if (cell_layout_block->BorderBottom() > 0) {
cells_with_bottom_border++;
}
if (cell_layout_block->BorderLeft() > 0) {
cells_with_left_border++;
}
if (cell_layout_block->BorderRight() > 0) {
cells_with_right_border++;
}
// If the cell has a different color from the table and there is cell
// spacing, then it is probably a data table cell (spacing and colors take
// the place of borders).
Color cell_color = computed_style->VisitedDependentColor(
GetCSSPropertyBackgroundColor());
if (has_cell_spacing && table_bg_color != cell_color &&
!cell_color.IsFullyTransparent()) {
background_difference_cell_count++;
}
// If we've found 10 "good" cells, we don't need to keep searching.
if (bordered_cell_count >= 10 || background_difference_cell_count >= 10) {
return true;
}
// For the first 5 rows, cache the background color so we can check if
// this table has zebra-striped rows.
if (row < 5 && row == alternating_row_color_count) {
LayoutObject* layout_row = cell_layout_block->Parent();
if (!layout_row || !layout_row->IsBoxModelObject() ||
!layout_row->IsTableRow()) {
continue;
}
const ComputedStyle* row_computed_style = layout_row->Style();
if (!row_computed_style) {
continue;
}
Color row_color = row_computed_style->VisitedDependentColor(
GetCSSPropertyBackgroundColor());
alternating_row_colors[alternating_row_color_count] = row_color;
alternating_row_color_count++;
}
}
}
// if there is less than two valid cells, it's not a data table
if (valid_cell_count <= 1) {
return false;
}
// half of the cells had borders, it's a data table
unsigned needed_cell_count = valid_cell_count / 2;
if (bordered_cell_count >= needed_cell_count ||
cells_with_top_border >= needed_cell_count ||
cells_with_bottom_border >= needed_cell_count ||
cells_with_left_border >= needed_cell_count ||
cells_with_right_border >= needed_cell_count) {
return true;
}
// half had different background colors, it's a data table
if (background_difference_cell_count >= needed_cell_count) {
return true;
}
// Check if there is an alternating row background color indicating a zebra
// striped style pattern.
if (alternating_row_color_count > 2) {
Color first_color = alternating_row_colors[0];
for (int k = 1; k < alternating_row_color_count; k++) {
// If an odd row was the same color as the first row, its not alternating.
if (k % 2 == 1 && alternating_row_colors[k] == first_color) {
return false;
}
// If an even row is not the same as the first row, its not alternating.
if (!(k % 2) && alternating_row_colors[k] != first_color) {
return false;
}
}
return true;
}
return false;
}
// TODO(accessibility) Consider combining with NativeRoleIgnoringAria().
ax::mojom::blink::Role AXNodeObject::RoleFromLayoutObjectOrNode() const {
if (!GetLayoutObject()) {
return ax::mojom::blink::Role::kGenericContainer;
}
DCHECK(GetLayoutObject());
if (GetLayoutObject()->IsListMarker()) {
Node* list_item = GetLayoutObject()->GeneratingNode();
if (list_item && ShouldIgnoreListItem(list_item)) {
return ax::mojom::blink::Role::kNone;
}
return ax::mojom::blink::Role::kListMarker;
}
if (GetLayoutObject()->IsListItem()) {
return ax::mojom::blink::Role::kListItem;
}
if (GetLayoutObject()->IsBR()) {
return ax::mojom::blink::Role::kLineBreak;
}
if (GetLayoutObject()->IsText()) {
return ax::mojom::blink::Role::kStaticText;
}
Node* node = GetNode(); // Can be null in the case of pseudo content.
// Chrome exposes both table markup and table CSS as a tables, letting
// the screen reader determine what to do for CSS tables. If this line
// is reached, then it is not an HTML table, and therefore will only be
// considered a data table if ARIA markup indicates it is a table.
// Additionally, as pseudo-elements don't have any structure it doesn't make
// sense to report their table-related layout roles that could be set via the
// display property.
if (node && !node->IsPseudoElement()) {
if (GetLayoutObject()->IsTable()) {
return ax::mojom::blink::Role::kLayoutTable;
}
if (GetLayoutObject()->IsTableSection()) {
return DetermineTableSectionRole();
}
if (GetLayoutObject()->IsTableRow()) {
return DetermineTableRowRole();
}
if (GetLayoutObject()->IsTableCell()) {
return DetermineTableCellRole();
}
}
if (IsImageOrAltText(GetLayoutObject(), node)) {
if (IsA<HTMLInputElement>(node)) {
return ButtonRoleType();
}
return ax::mojom::blink::Role::kImage;
}
if (IsA<HTMLCanvasElement>(node)) {
return ax::mojom::blink::Role::kCanvas;
}
if (IsA<LayoutView>(GetLayoutObject())) {
return ParentObject() ? ax::mojom::blink::Role::kGroup
: ax::mojom::blink::Role::kRootWebArea;
}
if (node && node->IsSVGElement()) {
if (GetLayoutObject()->IsSVGImage()) {
return ax::mojom::blink::Role::kImage;
}
if (IsA<SVGSVGElement>(node)) {
// Exposing a nested <svg> as a group (rather than a generic container)
// increases the likelihood that an author-provided name will be presented
// by assistive technologies. Note that this mapping is not yet in the
// SVG-AAM, which currently maps all <svg> elements as graphics-document.
// See https://github.com/w3c/svg-aam/issues/18.
return GetLayoutObject()->IsSVGRoot() ? ax::mojom::blink::Role::kSvgRoot
: ax::mojom::blink::Role::kGroup;
}
if (GetLayoutObject()->IsSVGShape()) {
return ax::mojom::blink::Role::kGraphicsSymbol;
}
if (GetLayoutObject()->IsSVGForeignObject()) {
return ax::mojom::blink::Role::kGroup;
}
if (IsA<SVGUseElement>(node)) {
return ax::mojom::blink::Role::kGraphicsObject;
}
}
if (GetLayoutObject()->IsHR()) {
return ax::mojom::blink::Role::kSplitter;
}
// If the originating element (the scroller) of ::scroll-marker-group to
// which ::scroll-marker belongs has scroll-marker-group set to `tabs` mode,
// the originating element of ::scroll-marker is given an implicit
// role of tabpanel.
if (RuntimeEnabledFeatures::CSSScrollMarkerGroupModesEnabled() &&
IsOriginatingElementForScrollMarkerInTabsMode(node)) {
return ax::mojom::blink::Role::kTabPanel;
}
// Minimum role:
// TODO(accessibility) if (AXObjectCache().IsInternalUICheckerOn()) assert,
// because it is a bad code smell and usually points to other problems.
if (GetElement() && !HasAriaAttribute(html_names::kRoleAttr)) {
if (IsPopup() != ax::mojom::blink::IsPopup::kNone ||
GetElement()->FastHasAttribute(html_names::kAutofocusAttr) ||
GetElement()->FastHasAttribute(html_names::kDraggableAttr)) {
return ax::mojom::blink::Role::kGroup;
}
if (RuntimeEnabledFeatures::AccessibilityMinRoleTabbableEnabled()) {
if (GetElement()->tabIndex() >= 0) {
return ax::mojom::blink::Role::kGroup;
}
}
}
// Custom elements have additional minimum role rules.
if (HasCustomElementTreeProcessing()) {
if (ElementHasAnyAriaRelation(*GetElement()) ||
GetElement()->tabIndex() >= 0) {
return ax::mojom::blink::Role::kGroup;
}
}
if (IsA<HTMLPermissionElement>(node)) {
return ax::mojom::blink::Role::kButton;
}
if (IsA<HTMLMenuBarElement>(node)) {
return ax::mojom::blink::Role::kMenuBar;
}
if (IsA<HTMLMenuItemElement>(node)) {
return ax::mojom::blink::Role::kMenuItem;
}
if (IsA<HTMLMenuListElement>(node)) {
return ax::mojom::blink::Role::kMenu;
}
// Anything that needs to be exposed but doesn't have a more specific role
// should be considered a generic container. Examples are layout blocks with
// no node, in-page link targets, and plain elements such as a <span> with
// an aria- property.
return ax::mojom::blink::Role::kGenericContainer;
}
// Does not check ARIA role, but does check some ARIA properties, specifically
// @aria-haspopup/aria-pressed via ButtonType().
ax::mojom::blink::Role AXNodeObject::NativeRoleIgnoringAria() const {
if (!GetNode()) {
// Can be null in the case of pseudo content.
return RoleFromLayoutObjectOrNode();
}
if (GetNode()->IsPseudoElement()) {
// This is for carousel scroll buttons (left/right/up/down) which are meant
// to look and act like buttons, but are generated as ::scroll-button(...)
// pseudos.
if (GetNode()->IsScrollButtonPseudoElement()) {
return ax::mojom::blink::Role::kButton;
}
if (RuntimeEnabledFeatures::CSSScrollMarkerGroupModesEnabled()) {
// Carousel ::scroll-marker-group is either a kTabList or a kNavigation,
// based on the scroll-marker-group property of its originating element.
if (const auto* scroll_marker_group =
DynamicTo<ScrollMarkerGroupPseudoElement>(GetNode())) {
return scroll_marker_group->ScrollMarkerGroupMode() ==
ScrollMarkerGroup::ScrollMarkerMode::kTabs
? ax::mojom::blink::Role::kTabList
: ax::mojom::blink::Role::kNavigation;
}
// Carousel ::scroll-marker within a group is either a kTab or a kLink,
// based on the scroll-marker-group property of its
// ::scroll-marker-group's originating element.
if (const auto* scroll_marker =
DynamicTo<ScrollMarkerPseudoElement>(GetNode())) {
CHECK(scroll_marker->ScrollMarkerGroup());
return scroll_marker->ScrollMarkerGroup()->ScrollMarkerGroupMode() ==
ScrollMarkerGroup::ScrollMarkerMode::kTabs
? ax::mojom::blink::Role::kTab
: ax::mojom::blink::Role::kLink;
}
} else {
// Carousel ::scroll-marker-group is a kTabList.
if (GetNode()->IsScrollMarkerGroupPseudoElement()) {
return ax::mojom::blink::Role::kTabList;
}
// Carousel ::scroll-marker within a group is a kTab.
if (GetNode()->IsScrollMarkerPseudoElement()) {
return ax::mojom::blink::Role::kTab;
}
}
if (GetCSSAltText(GetElement())) {
const ComputedStyle* style = GetElement()->GetComputedStyle();
ContentData* content_data = style->GetContentData();
// We just check the first item of the content list to determine the
// appropriate role, should only ever be image or text.
// TODO(accessibility) Is it possible to use CSS alt text on an HTML tag
// with strong semantics? If so, why are we overriding the role here?
// We only need to ensure the accessible name gets the CSS alt text.
// Note: by doing this, we are often hiding child pseudo-element content
// because IsRelevantPseudoElementDescendant() returns false when an
// ancestor has CSS alt text.
if (content_data->IsImage()) {
return ax::mojom::blink::Role::kImage;
}
return ax::mojom::blink::Role::kStaticText;
}
}
if (GetNode()->IsTextNode())
return ax::mojom::blink::Role::kStaticText;
if (IsA<HTMLImageElement>(GetNode()))
return ax::mojom::blink::Role::kImage;
// <a> or <svg:a>.
if (IsA<HTMLAnchorElement>(GetNode()) || IsA<SVGAElement>(GetNode())) {
// Assume that an anchor element is a Role::kLink if it has an href or a
// click event listener.
if (GetNode()->IsLink() ||
GetNode()->HasAnyEventListeners(event_util::MouseButtonEventTypes())) {
return ax::mojom::blink::Role::kLink;
}
// According to the SVG-AAM, a non-link 'a' element should be exposed like
// a 'g' if it does not descend from a 'text' element and like a 'tspan'
// if it does. This is consistent with the SVG spec which states that an
// 'a' within 'text' acts as an inline element, whereas it otherwise acts
// as a container element.
if (IsA<SVGAElement>(GetNode()) &&
!Traversal<SVGTextElement>::FirstAncestor(*GetNode())) {
return ax::mojom::blink::Role::kGroup;
}
return ax::mojom::blink::Role::kGenericContainer;
}
if (IsA<SVGGElement>(*GetNode())) {
return ax::mojom::blink::Role::kGroup;
}
if (IsA<HTMLButtonElement>(*GetNode()))
return ButtonRoleType();
if (IsA<HTMLDetailsElement>(*GetNode()))
return ax::mojom::blink::Role::kDetails;
if (IsA<HTMLSummaryElement>(*GetNode())) {
ContainerNode* parent = LayoutTreeBuilderTraversal::Parent(*GetNode());
if (ToHTMLSlotElementIfSupportsAssignmentOrNull(parent))
parent = LayoutTreeBuilderTraversal::Parent(*parent);
if (HTMLDetailsElement* parent_details =
DynamicTo<HTMLDetailsElement>(parent)) {
if (parent_details->GetName().empty()) {
return ax::mojom::blink::Role::kDisclosureTriangle;
} else {
return ax::mojom::blink::Role::kDisclosureTriangleGrouped;
}
}
return ax::mojom::blink::Role::kGenericContainer;
}
// Chrome exposes both table markup and table CSS as a table, letting
// the screen reader determine what to do for CSS tables.
if (IsA<HTMLTableElement>(*GetNode())) {
if (IsDataTable())
return ax::mojom::blink::Role::kTable;
else
return ax::mojom::blink::Role::kLayoutTable;
}
if (IsA<HTMLTableRowElement>(*GetNode()))
return DetermineTableRowRole();
if (IsA<HTMLTableCellElement>(*GetNode()))
return DetermineTableCellRole();
if (IsA<HTMLTableSectionElement>(*GetNode()))
return DetermineTableSectionRole();
if (const auto* input = DynamicTo<HTMLInputElement>(*GetNode())) {
FormControlType type = input->FormControlType();
if (input->DataList() && type != FormControlType::kInputColor) {
return ax::mojom::blink::Role::kTextFieldWithComboBox;
}
switch (type) {
case FormControlType::kInputButton:
case FormControlType::kInputReset:
case FormControlType::kInputSubmit:
return ButtonRoleType();
case FormControlType::kInputCheckbox:
return ax::mojom::blink::Role::kCheckBox;
case FormControlType::kInputDate:
return ax::mojom::blink::Role::kDate;
case FormControlType::kInputDatetimeLocal:
case FormControlType::kInputMonth:
case FormControlType::kInputWeek:
return ax::mojom::blink::Role::kDateTime;
case FormControlType::kInputFile:
return ax::mojom::blink::Role::kButton;
case FormControlType::kInputRadio:
return ax::mojom::blink::Role::kRadioButton;
case FormControlType::kInputNumber:
return ax::mojom::blink::Role::kSpinButton;
case FormControlType::kInputRange:
return ax::mojom::blink::Role::kSlider;
case FormControlType::kInputSearch:
return ax::mojom::blink::Role::kSearchBox;
case FormControlType::kInputColor:
return ax::mojom::blink::Role::kColorWell;
case FormControlType::kInputTime:
return ax::mojom::blink::Role::kInputTime;
case FormControlType::kInputImage:
return ax::mojom::blink::Role::kButton;
default:
return ax::mojom::blink::Role::kTextField;
}
}
if (auto* select_element = DynamicTo<HTMLSelectElement>(*GetNode())) {
if (select_element->UsesMenuList() && !select_element->IsMultiple()) {
return ax::mojom::blink::Role::kComboBoxSelect;
} else {
return ax::mojom::blink::Role::kListBox;
}
}
if (ParentObjectIfPresent() && ParentObjectIfPresent()->RoleValue() ==
ax::mojom::blink::Role::kComboBoxSelect) {
if (HTMLSelectElement::IsPopoverPickerElement(GetNode())) {
return ax::mojom::blink::Role::kMenuListPopup;
}
}
if (auto* option = DynamicTo<HTMLOptionElement>(*GetNode())) {
HTMLSelectElement* select_element = option->OwnerSelectElement();
if (select_element && select_element->UsesMenuList() &&
!select_element->IsMultiple()) {
return ax::mojom::blink::Role::kMenuListOption;
} else {
return ax::mojom::blink::Role::kListBoxOption;
}
}
if (IsA<HTMLOptGroupElement>(GetNode())) {
return ax::mojom::blink::Role::kGroup;
}
if (IsA<HTMLTextAreaElement>(*GetNode()))
return ax::mojom::blink::Role::kTextField;
if (HeadingLevel())
return ax::mojom::blink::Role::kHeading;
if (IsA<HTMLDivElement>(*GetNode()))
return RoleFromLayoutObjectOrNode();
if (IsA<HTMLMenuElement>(*GetNode()) || IsA<HTMLUListElement>(*GetNode()) ||
IsA<HTMLOListElement>(*GetNode())) {
// <menu> is a deprecated feature of HTML 5, but is included for semantic
// compatibility with HTML3, and may contain list items. Exposing it as an
// unordered list works better than the current HTML-AAM recommendaton of
// exposing as a role=menu, because if it's just used semantically, it won't
// be interactive. If used as a widget, the author must provide role=menu.
return ax::mojom::blink::Role::kList;
}
if (IsA<HTMLLIElement>(*GetNode())) {
if (ShouldIgnoreListItem(GetNode())) {
return ax::mojom::blink::Role::kNone;
}
return ax::mojom::blink::Role::kListItem;
}
if (IsA<HTMLMeterElement>(*GetNode()))
return ax::mojom::blink::Role::kMeter;
if (IsA<HTMLProgressElement>(*GetNode()))
return ax::mojom::blink::Role::kProgressIndicator;
if (IsA<HTMLOutputElement>(*GetNode()))
return ax::mojom::blink::Role::kStatus;
if (IsA<HTMLParagraphElement>(*GetNode()))
return ax::mojom::blink::Role::kParagraph;
if (IsA<HTMLLabelElement>(*GetNode()))
return ax::mojom::blink::Role::kLabelText;
if (IsA<HTMLLegendElement>(*GetNode()))
return ax::mojom::blink::Role::kLegend;
if (GetNode()->HasTagName(html_names::kRubyTag)) {
return ax::mojom::blink::Role::kRuby;
}
if (IsA<HTMLDListElement>(*GetNode()))
return ax::mojom::blink::Role::kDescriptionList;
if (IsA<HTMLDirectoryElement>(*GetNode())) {
return ax::mojom::blink::Role::kList;
}
if (IsA<HTMLAudioElement>(*GetNode()))
return ax::mojom::blink::Role::kAudio;
if (IsA<HTMLVideoElement>(*GetNode()))
return ax::mojom::blink::Role::kVideo;
if (GetNode()->HasTagName(html_names::kDdTag))
return ax::mojom::blink::Role::kDefinition;
if (GetNode()->HasTagName(html_names::kDfnTag))
return ax::mojom::blink::Role::kTerm;
if (GetNode()->HasTagName(html_names::kDtTag))
return ax::mojom::blink::Role::kTerm;
// Mapping of MathML elements. See https://w3c.github.io/mathml-aam/
if (auto* element = DynamicTo<MathMLElement>(GetNode())) {
if (element->HasTagName(mathml_names::kMathTag)) {
return ax::mojom::blink::Role::kMathMLMath;
}
if (element->HasTagName(mathml_names::kMfracTag))
return ax::mojom::blink::Role::kMathMLFraction;
if (element->HasTagName(mathml_names::kMiTag))
return ax::mojom::blink::Role::kMathMLIdentifier;
if (element->HasTagName(mathml_names::kMmultiscriptsTag))
return ax::mojom::blink::Role::kMathMLMultiscripts;
if (element->HasTagName(mathml_names::kMnTag))
return ax::mojom::blink::Role::kMathMLNumber;
if (element->HasTagName(mathml_names::kMoTag))
return ax::mojom::blink::Role::kMathMLOperator;
if (element->HasTagName(mathml_names::kMoverTag))
return ax::mojom::blink::Role::kMathMLOver;
if (element->HasTagName(mathml_names::kMunderTag))
return ax::mojom::blink::Role::kMathMLUnder;
if (element->HasTagName(mathml_names::kMunderoverTag))
return ax::mojom::blink::Role::kMathMLUnderOver;
if (element->HasTagName(mathml_names::kMrootTag))
return ax::mojom::blink::Role::kMathMLRoot;
if (element->HasTagName(mathml_names::kMrowTag) ||
element->HasTagName(mathml_names::kAnnotationXmlTag) ||
element->HasTagName(mathml_names::kMactionTag) ||
element->HasTagName(mathml_names::kMerrorTag) ||
element->HasTagName(mathml_names::kMpaddedTag) ||
element->HasTagName(mathml_names::kMphantomTag) ||
element->HasTagName(mathml_names::kMstyleTag) ||
element->HasTagName(mathml_names::kSemanticsTag)) {
return ax::mojom::blink::Role::kMathMLRow;
}
if (element->HasTagName(mathml_names::kMprescriptsTag))
return ax::mojom::blink::Role::kMathMLPrescriptDelimiter;
if (element->HasTagName(mathml_names::kNoneTag))
return ax::mojom::blink::Role::kMathMLNoneScript;
if (element->HasTagName(mathml_names::kMsqrtTag))
return ax::mojom::blink::Role::kMathMLSquareRoot;
if (element->HasTagName(mathml_names::kMsTag))
return ax::mojom::blink::Role::kMathMLStringLiteral;
if (element->HasTagName(mathml_names::kMsubTag))
return ax::mojom::blink::Role::kMathMLSub;
if (element->HasTagName(mathml_names::kMsubsupTag))
return ax::mojom::blink::Role::kMathMLSubSup;
if (element->HasTagName(mathml_names::kMsupTag))
return ax::mojom::blink::Role::kMathMLSup;
if (element->HasTagName(mathml_names::kMtableTag))
return ax::mojom::blink::Role::kMathMLTable;
if (element->HasTagName(mathml_names::kMtdTag))
return ax::mojom::blink::Role::kMathMLTableCell;
if (element->HasTagName(mathml_names::kMtrTag))
return ax::mojom::blink::Role::kMathMLTableRow;
if (element->HasTagName(mathml_names::kMtextTag) ||
element->HasTagName(mathml_names::kAnnotationTag)) {
return ax::mojom::blink::Role::kMathMLText;
}
}
if (GetNode()->HasTagName(html_names::kRpTag) ||
GetNode()->HasTagName(html_names::kRtTag)) {
return ax::mojom::blink::Role::kRubyAnnotation;
}
if (IsA<HTMLFormElement>(*GetNode())) {
// Only treat <form> as role="form" when it has an accessible name, which
// can only occur when the name is assigned by the author via aria-label,
// aria-labelledby, or title. Otherwise, treat as a <section>.
return IsNameFromAuthorAttribute() ? ax::mojom::blink::Role::kForm
: ax::mojom::blink::Role::kSection;
}
if (GetNode()->HasTagName(html_names::kAbbrTag))
return ax::mojom::blink::Role::kAbbr;
if (GetNode()->HasTagName(html_names::kArticleTag))
return ax::mojom::blink::Role::kArticle;
if (GetNode()->HasTagName(html_names::kCodeTag))
return ax::mojom::blink::Role::kCode;
if (GetNode()->HasTagName(html_names::kEmTag))
return ax::mojom::blink::Role::kEmphasis;
if (GetNode()->HasTagName(html_names::kStrongTag))
return ax::mojom::blink::Role::kStrong;
if (GetNode()->HasTagName(html_names::kSearchTag)) {
return ax::mojom::blink::Role::kSearch;
}
if (GetNode()->HasTagName(html_names::kDelTag) ||
GetNode()->HasTagName(html_names::kSTag)) {
return ax::mojom::blink::Role::kContentDeletion;
}
if (GetNode()->HasTagName(html_names::kInsTag))
return ax::mojom::blink::Role::kContentInsertion;
if (GetNode()->HasTagName(html_names::kSubTag))
return ax::mojom::blink::Role::kSubscript;
if (GetNode()->HasTagName(html_names::kSupTag))
return ax::mojom::blink::Role::kSuperscript;
if (GetNode()->HasTagName(html_names::kMainTag))
return ax::mojom::blink::Role::kMain;
if (GetNode()->HasTagName(html_names::kMarkTag))
return ax::mojom::blink::Role::kMark;
if (GetNode()->HasTagName(html_names::kNavTag))
return ax::mojom::blink::Role::kNavigation;
if (GetNode()->HasTagName(html_names::kAsideTag))
return ax::mojom::blink::Role::kComplementary;
if (GetNode()->HasTagName(html_names::kSectionTag)) {
return ax::mojom::blink::Role::kSection;
}
if (GetNode()->HasTagName(html_names::kAddressTag))
return ax::mojom::blink::Role::kGroup;
if (GetNode()->HasTagName(html_names::kHgroupTag)) {
return ax::mojom::blink::Role::kGroup;
}
if (IsA<HTMLDialogElement>(*GetNode()))
return ax::mojom::blink::Role::kDialog;
// The HTML element.
if (IsA<HTMLHtmlElement>(GetNode()))
return ax::mojom::blink::Role::kGenericContainer;
// Treat <iframe>, <frame> and <fencedframe> the same.
if (IsFrame(GetNode()))
return ax::mojom::blink::Role::kIframe;
if (GetNode()->HasTagName(html_names::kHeaderTag)) {
return ax::mojom::blink::Role::kHeader;
}
if (GetNode()->HasTagName(html_names::kFooterTag)) {
return ax::mojom::blink::Role::kFooter;
}
if (GetNode()->HasTagName(html_names::kBlockquoteTag))
return ax::mojom::blink::Role::kBlockquote;
if (IsA<HTMLTableCaptionElement>(GetNode()))
return ax::mojom::blink::Role::kCaption;
if (GetNode()->HasTagName(html_names::kFigcaptionTag))
return ax::mojom::blink::Role::kFigcaption;
if (GetNode()->HasTagName(html_names::kFigureTag))
return ax::mojom::blink::Role::kFigure;
if (IsA<HTMLTimeElement>(GetNode()))
return ax::mojom::blink::Role::kTime;
if (IsA<HTMLPlugInElement>(GetNode())) {
if (IsA<HTMLEmbedElement>(GetNode()))
return ax::mojom::blink::Role::kEmbeddedObject;
return ax::mojom::blink::Role::kPluginObject;
}
if (IsA<HTMLHRElement>(*GetNode()))
return ax::mojom::blink::Role::kSplitter;
if (IsFieldset())
return ax::mojom::blink::Role::kGroup;
return RoleFromLayoutObjectOrNode();
}
ax::mojom::blink::Role AXNodeObject::DetermineRoleValue() {
#if DCHECK_IS_ON()
base::AutoReset<bool> reentrancy_protector(&is_computing_role_, true);
#endif
if (IsDetached()) {
NOTREACHED() << "Do not compute role on detached object: " << this;
}
native_role_ = NativeRoleIgnoringAria();
aria_role_ = DetermineAriaRole();
return aria_role_ == ax::mojom::blink::Role::kUnknown ? native_role_
: aria_role_;
}
static Element* SiblingWithAriaRole(String role, Node* node) {
Node* parent = LayoutTreeBuilderTraversal::Parent(*node);
if (!parent)
return nullptr;
for (Node* sibling = LayoutTreeBuilderTraversal::FirstChild(*parent); sibling;
sibling = LayoutTreeBuilderTraversal::NextSibling(*sibling)) {
auto* element = DynamicTo<Element>(sibling);
if (!element)
continue;
const AtomicString& sibling_aria_role =
blink::AXObject::AriaAttribute(*element, html_names::kRoleAttr);
if (EqualIgnoringASCIICase(sibling_aria_role, role))
return element;
}
return nullptr;
}
Element* AXNodeObject::MenuItemElementForMenu() const {
if (RawAriaRole() != ax::mojom::blink::Role::kMenu) {
return nullptr;
}
return SiblingWithAriaRole("menuitem", GetNode());
}
void AXNodeObject::Init(AXObject* parent) {
#if DCHECK_IS_ON()
DCHECK(!initialized_);
initialized_ = true;
#endif
AXObject::Init(parent);
DCHECK(role_ == native_role_ || role_ == aria_role_)
<< "Role must be either the cached native role or cached aria role: "
<< "\n* Final role: " << role_ << "\n* Native role: " << native_role_
<< "\n* Aria role: " << aria_role_ << "\n* Node: " << GetNode();
DCHECK(node_ || (GetLayoutObject() &&
AXObjectCacheImpl::IsRelevantPseudoElementDescendant(
*GetLayoutObject())))
<< "Nodeless AXNodeObject can only exist inside a pseudo-element: "
<< GetLayoutObject();
}
void AXNodeObject::Detach() {
#if AX_FAIL_FAST_BUILD()
SANITIZER_CHECK(!is_adding_children_)
<< "Cannot detach |this| during AddChildren(): " << GetNode();
#endif
AXObject::Detach();
node_ = nullptr;
#if DCHECK_IS_ON()
if (layout_object_) {
layout_object_->SetHasAXObject(false);
}
#endif
layout_object_ = nullptr;
}
bool AXNodeObject::IsAXNodeObject() const {
return true;
}
bool AXNodeObject::IsControl() const {
Node* node = GetNode();
if (!node)
return false;
auto* element = DynamicTo<Element>(node);
return ((element && element->IsFormControlElement()) ||
ui::IsControl(RawAriaRole()));
}
bool AXNodeObject::IsAutofillAvailable() const {
// Autofill suggestion availability is stored in AXObjectCache.
WebAXAutofillSuggestionAvailability suggestion_availability =
AXObjectCache().GetAutofillSuggestionAvailability(AXObjectID());
return suggestion_availability ==
WebAXAutofillSuggestionAvailability::kAutofillAvailable;
}
bool AXNodeObject::IsDefault() const {
if (IsDetached())
return false;
// Checks for any kind of disabled, including aria-disabled.
if (Restriction() == kRestrictionDisabled ||
RoleValue() != ax::mojom::blink::Role::kButton) {
return false;
}
// Will only match :default pseudo-class if it's the first default button in
// a form.
return GetElement()->MatchesDefaultPseudoClass();
}
bool AXNodeObject::IsFieldset() const {
return IsA<HTMLFieldSetElement>(GetNode());
}
bool AXNodeObject::IsHovered() const {
if (Node* node = GetNode())
return node->IsHovered();
return false;
}
bool AXNodeObject::IsImageButton() const {
return IsNativeImage() && IsButton();
}
bool AXNodeObject::IsInputImage() const {
auto* html_input_element = DynamicTo<HTMLInputElement>(GetNode());
if (html_input_element && RoleValue() == ax::mojom::blink::Role::kButton) {
return html_input_element->FormControlType() ==
FormControlType::kInputImage;
}
return false;
}
bool AXNodeObject::IsLineBreakingObject() const {
// According to Blink Editing, objects without an associated DOM node such as
// pseudo-elements and list bullets, are never considered as paragraph
// boundaries.
if (IsDetached() || !GetNode())
return false;
// Presentational objects should not contribute any of their semantic meaning
// to the accessibility tree, including to its text representation.
if (IsPresentational())
return false;
// `IsEnclosingBlock` includes all elements with display block, inline block,
// table related, flex, grid, list item, flow-root, webkit-box, and display
// contents. This is the same function used by Blink > Editing for determining
// paragraph boundaries, i.e. line breaking objects.
if (IsEnclosingBlock(GetNode()))
return true;
// Not all <br> elements have an associated layout object. They might be
// "visibility: hidden" or within a display locked region. We need to check
// their DOM node first.
if (IsA<HTMLBRElement>(GetNode()))
return true;
const LayoutObject* layout_object = GetLayoutObject();
if (!layout_object)
return AXObject::IsLineBreakingObject();
if (layout_object->IsBR())
return true;
// LayoutText objects could include a paragraph break in their text. This can
// only occur if line breaks are preserved and a newline character is present
// in their collapsed text. Text collapsing removes all whitespace found in
// the HTML file, but a special style rule could be used to preserve line
// breaks.
//
// The best example is the <pre> element:
// <pre>Line 1
// Line 2</pre>
if (const LayoutText* layout_text = DynamicTo<LayoutText>(layout_object)) {
const ComputedStyle& style = layout_object->StyleRef();
if (layout_text->HasNonCollapsedText() && style.ShouldPreserveBreaks() &&
layout_text->PlainText().find('\n') != kNotFound) {
return true;
}
}
// Rely on the ARIA role to figure out if this object is line breaking.
return AXObject::IsLineBreakingObject();
}
bool AXNodeObject::IsLoaded() const {
if (!GetDocument())
return false;
if (!GetDocument()->IsLoadCompleted())
return false;
// Check for a navigation API single-page app navigation in progress.
if (auto* window = GetDocument()->domWindow()) {
if (window->navigation()->HasNonDroppedOngoingNavigation())
return false;
}
return true;
}
bool AXNodeObject::IsMultiSelectable() const {
switch (RoleValue()) {
case ax::mojom::blink::Role::kGrid:
case ax::mojom::blink::Role::kTreeGrid:
case ax::mojom::blink::Role::kTree:
case ax::mojom::blink::Role::kListBox:
case ax::mojom::blink::Role::kTabList:
bool multiselectable;
if (AriaBooleanAttribute(html_names::kAriaMultiselectableAttr,
&multiselectable)) {
return multiselectable;
}
break;
default:
break;
}
auto* html_select_element = DynamicTo<HTMLSelectElement>(GetNode());
return html_select_element && html_select_element->IsMultiple();
}
bool AXNodeObject::IsNativeImage() const {
Node* node = GetNode();
if (!node)
return false;
if (IsA<HTMLImageElement>(*node) || IsA<HTMLPlugInElement>(*node))
return true;
if (const auto* input = DynamicTo<HTMLInputElement>(*node))
return input->FormControlType() == FormControlType::kInputImage;
return false;
}
bool AXNodeObject::IsVisible() const {
// Any descendant of a <select size=1> should be considered invisible if
// the select is collapsed.
if (RoleValue() == ax::mojom::blink::Role::kMenuListPopup) {
CHECK(parent_);
return parent_->IsExpanded() == kExpandedExpanded;
}
if (IsRoot()) {
return true;
}
// Anything else inside of a collapsed select is also invisible.
if (const AXObject* ax_select = ParentObject()->AncestorMenuList()) {
// If the select is invisible, so is everything inside of it.
if (!ax_select->IsVisible()) {
return false;
}
// Inside of a collapsed select:
// - The selected option's subtree is visible.
// - Everything else is invisible.
if (ax_select->IsExpanded() == kExpandedCollapsed) {
if (const AXObject* ax_option = AncestorMenuListOption()) {
return ax_option->IsSelected() == kSelectedStateTrue;
}
return false;
}
}
return AXObject::IsVisible();
}
bool AXNodeObject::IsLinked() const {
if (!IsLinkable(*this)) {
return false;
}
if (auto* anchor = DynamicTo<HTMLAnchorElementBase>(AnchorElement())) {
return !anchor->Href().IsEmpty();
}
return false;
}
bool AXNodeObject::IsVisited() const {
return GetLayoutObject() && GetLayoutObject()->Style()->IsLink() &&
GetLayoutObject()->Style()->InsideLink() ==
EInsideLink::kInsideVisitedLink;
}
bool AXNodeObject::IsProgressIndicator() const {
return RoleValue() == ax::mojom::blink::Role::kProgressIndicator;
}
bool AXNodeObject::IsSlider() const {
return RoleValue() == ax::mojom::blink::Role::kSlider;
}
bool AXNodeObject::IsSpinButton() const {
return RoleValue() == ax::mojom::blink::Role::kSpinButton;
}
bool AXNodeObject::IsNativeSlider() const {
if (const auto* input = DynamicTo<HTMLInputElement>(GetNode()))
return input->FormControlType() == FormControlType::kInputRange;
return false;
}
bool AXNodeObject::IsNativeSpinButton() const {
if (const auto* input = DynamicTo<HTMLInputElement>(GetNode()))
return input->FormControlType() == FormControlType::kInputNumber;
return false;
}
bool AXNodeObject::IsEmbeddingElement() const {
return ui::IsEmbeddingElement(native_role_);
}
bool AXNodeObject::IsClickable() const {
// Determine whether the element is clickable either because there is a
// mouse button handler or because it has a native element where click
// performs an action. Disabled nodes are never considered clickable.
// Note: we can't call |node->WillRespondToMouseClickEvents()| because that
// triggers a style recalc and can delete this.
// Treat mouse button listeners on the |window|, |document| as if they're on
// the |documentElement|.
if (GetNode() == GetDocument()->documentElement()) {
return GetNode()->HasAnyEventListeners(
event_util::MouseButtonEventTypes()) ||
GetDocument()->HasAnyEventListeners(
event_util::MouseButtonEventTypes()) ||
GetDocument()->domWindow()->HasAnyEventListeners(
event_util::MouseButtonEventTypes());
}
// Look for mouse listeners only on element nodes, e.g. skip text nodes.
const Element* element = GetElement();
if (!element)
return false;
if (IsDisabled())
return false;
if (element->HasAnyEventListeners(event_util::MouseButtonEventTypes()))
return true;
if (HasContentEditableAttributeSet())
return true;
// Certain user-agent shadow DOM elements are expected to be clickable but
// they do not have event listeners attached or a clickable native role. We
// whitelist them here.
if (element->ShadowPseudoId() ==
shadow_element_names::kPseudoCalendarPickerIndicator) {
return true;
}
// Only use native roles. For ARIA elements, require a click listener.
return ui::IsClickable(native_role_);
}
bool AXNodeObject::IsFocused() const {
if (!GetDocument())
return false;
// A web area is represented by the Document node in the DOM tree, which isn't
// focusable. Check instead if the frame's selection controller is focused.
if (IsWebArea() &&
GetDocument()->GetFrame()->Selection().FrameIsFocusedAndActive()) {
return true;
}
Element* focused_element = GetDocument()->FocusedElement();
return focused_element && focused_element == GetElement();
}
AccessibilitySelectedState AXNodeObject::IsSelected() const {
if (!GetNode() || !IsSubWidget()) {
return kSelectedStateUndefined;
}
// The aria-selected attribute overrides automatic behaviors.
bool is_selected;
if (AriaBooleanAttribute(html_names::kAriaSelectedAttr, &is_selected)) {
return is_selected ? kSelectedStateTrue : kSelectedStateFalse;
}
// The selection should only follow the focus when the aria-selected attribute
// is marked as required or implied for this element in the ARIA specs.
// If this object can't follow the focus, then we can't say that it's selected
// nor that it's not.
if (!ui::IsSelectRequiredOrImplicit(RoleValue()))
return kSelectedStateUndefined;
if (IsTabItem() && GetNode()->IsScrollMarkerPseudoElement()) {
return To<ScrollMarkerPseudoElement>(GetNode())->IsSelected()
? kSelectedStateTrue
: kSelectedStateFalse;
}
if (auto* option_element = DynamicTo<HTMLOptionElement>(GetNode())) {
if (!CanSetSelectedAttribute()) {
return kSelectedStateUndefined;
}
return (option_element->Selected()) ? kSelectedStateTrue
: kSelectedStateFalse;
}
// Selection follows focus, but ONLY in single selection containers, and only
// if aria-selected was not present to override.
return IsSelectedFromFocus() ? kSelectedStateTrue : kSelectedStateFalse;
}
bool AXNodeObject::IsSelectedFromFocusSupported() const {
// The selection should only follow the focus when the aria-selected attribute
// is marked as required or implied for this element in the ARIA specs.
// If this object can't follow the focus, then we can't say that it's selected
// nor that it's not.
// TODO(crbug.com/1143483): Consider allowing more roles.
if (!ui::IsSelectRequiredOrImplicit(RoleValue()))
return false;
// Selection follows focus only when in a single selection container.
const AXObject* container = ContainerWidget();
if (!container || container->IsMultiSelectable()) {
return false;
}
// Certain properties inside the container widget mean that implicit selection
// must be turned off.
if (!AXObjectCache().IsImplicitSelectionAllowed(container)) {
return false;
}
return true;
}
// In single selection containers, selection follows focus unless aria_selected
// is set to false. This is only valid for a subset of elements.
bool AXNodeObject::IsSelectedFromFocus() const {
// A tab item can also be selected if it is associated to a focused tabpanel
// via the aria-labelledby attribute.
if (IsTabItem() && IsSelectedFromFocusSupported() && IsTabItemSelected()) {
return true;
}
// If this object is not accessibility focused, then it is not selected from
// focus.
AXObject* focused_object = AXObjectCache().FocusedObject();
if (focused_object != this &&
(!focused_object || focused_object->ActiveDescendant() != this))
return false;
return IsSelectedFromFocusSupported();
}
// Returns true if the object is marked user-select:none
bool AXNodeObject::IsNotUserSelectable() const {
if (!GetLayoutObject()) {
return false;
}
if (IsA<PseudoElement>(GetClosestElement())) {
return true;
}
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style) {
return false;
}
return (style->UsedUserSelect() == EUserSelect::kNone);
}
bool AXNodeObject::IsTabItemSelected() const {
if (!IsTabItem() || !GetLayoutObject())
return false;
if (GetNode()->IsScrollMarkerPseudoElement()) {
return To<ScrollMarkerPseudoElement>(GetNode())->IsSelected();
}
Node* node = GetNode();
if (!node || !node->IsElementNode())
return false;
// The ARIA spec says a tab item can also be selected if it is aria-labeled by
// a tabpanel that has keyboard focus inside of it, or if a tabpanel in its
// aria-controls list has KB focus inside of it.
AXObject* focused_element = AXObjectCache().FocusedObject();
if (!focused_element)
return false;
DCHECK(GetElement());
const GCedHeapVector<Member<Element>>* elements =
AXObject::ElementsFromAttributeOrInternals(GetElement(),
html_names::kAriaControlsAttr);
if (!elements) {
return false;
}
for (const auto& element : *elements) {
AXObject* tab_panel = AXObjectCache().Get(element);
// A tab item should only control tab panels.
if (!tab_panel ||
tab_panel->RoleValue() != ax::mojom::blink::Role::kTabPanel) {
continue;
}
AXObject* check_focus_element = focused_element;
// Check if the focused element is a descendant of the element controlled by
// the tab item.
while (check_focus_element) {
if (tab_panel == check_focus_element)
return true;
check_focus_element = check_focus_element->ParentObject();
}
}
return false;
}
AXRestriction AXNodeObject::Restriction() const {
Element* elem = GetElement();
if (!elem)
return kRestrictionNone;
// An <optgroup> is not exposed directly in the AX tree.
if (IsA<HTMLOptGroupElement>(elem))
return kRestrictionNone;
// According to ARIA, all elements of the base markup can be disabled.
// According to CORE-AAM, any focusable descendant of aria-disabled
// ancestor is also disabled.
if (IsDisabled())
return kRestrictionDisabled;
// Only editable fields can be marked @readonly (unlike @aria-readonly).
auto* text_area_element = DynamicTo<HTMLTextAreaElement>(*elem);
if (text_area_element && text_area_element->IsReadOnly())
return kRestrictionReadOnly;
if (const auto* input = DynamicTo<HTMLInputElement>(*elem)) {
if (input->IsTextField() && input->IsReadOnly())
return kRestrictionReadOnly;
}
// Check aria-readonly if supported by current role.
bool is_read_only;
if (SupportsARIAReadOnly() &&
AriaBooleanAttribute(html_names::kAriaReadonlyAttr, &is_read_only)) {
// ARIA overrides other readonly state markup.
return is_read_only ? kRestrictionReadOnly : kRestrictionNone;
}
// If a grid cell does not have it's own ARIA input restriction,
// fall back on parent grid's readonly state.
// See ARIA specification regarding grid/treegrid and readonly.
if (IsTableCellLikeRole()) {
AXObject* row = ParentObjectUnignored();
if (row && row->IsTableRowLikeRole()) {
AXObject* table = row->ParentObjectUnignored();
if (table && table->IsTableLikeRole() &&
(table->RoleValue() == ax::mojom::blink::Role::kGrid ||
table->RoleValue() == ax::mojom::blink::Role::kTreeGrid)) {
if (table->Restriction() == kRestrictionReadOnly)
return kRestrictionReadOnly;
}
}
}
// This is a node that is not readonly and not disabled.
return kRestrictionNone;
}
AccessibilityExpanded AXNodeObject::IsExpanded() const {
if (!SupportsARIAExpanded())
return kExpandedUndefined;
auto* element = GetElement();
if (!element)
return kExpandedUndefined;
if (RoleValue() == ax::mojom::blink::Role::kComboBoxSelect) {
DCHECK(IsA<HTMLSelectElement>(element));
bool is_expanded = To<HTMLSelectElement>(element)->PopupIsVisible();
return is_expanded ? kExpandedExpanded : kExpandedCollapsed;
}
HTMLElement* command_for_element = nullptr;
if (auto* button = DynamicTo<HTMLButtonElement>(element)) {
command_for_element = DynamicTo<HTMLElement>(button->commandForElement());
} else if (auto* menuitem = DynamicTo<HTMLMenuItemElement>(element)) {
DCHECK(RuntimeEnabledFeatures::MenuElementsEnabled());
command_for_element = DynamicTo<HTMLElement>(menuitem->commandForElement());
}
// For menuitem and button elements that act as commandFor triggers,
// aria-expanded may be set depending on the command type. This results in the
// same mapping as popovertarget, but takes precedence in the case of
// conflicting markup as the HTML spec invokers commandfor functionality
// first, and only.
if (command_for_element) {
const AtomicString& action =
element->FastGetAttribute(html_names::kCommandAttr);
bool is_valid_popover_command =
command_for_element->IsValidBuiltinPopoverCommand(
*DynamicTo<HTMLElement>(element),
HTMLButtonElement::GetCommandEventType(
action,
command_for_element->GetDocument().GetExecutionContext()));
bool is_child =
element->IsDescendantOrShadowDescendantOf(command_for_element);
// Popover invokers should indicate the expanded/collapsed state.
if (is_valid_popover_command && !is_child) {
return command_for_element->popoverOpen() ? kExpandedExpanded
: kExpandedCollapsed;
}
}
// For form controls that act as triggering elements for popovers, then set
// aria-expanded=false when the popover is hidden, and aria-expanded=true when
// it is showing.
if (auto* form_control = DynamicTo<HTMLFormControlElement>(element)) {
if (auto popover = form_control->popoverTargetElement().popover) {
if (!form_control->IsDescendantOrShadowDescendantOf(popover)) {
// Only expose expanded/collapsed if the trigger button isn't contained
// within the popover itself. E.g. a close button within the popover.
return popover->popoverOpen() ? kExpandedExpanded : kExpandedCollapsed;
}
}
}
if (IsA<HTMLSummaryElement>(*element)) {
if (element->parentNode() &&
IsA<HTMLDetailsElement>(element->parentNode())) {
return To<Element>(element->parentNode())
->FastHasAttribute(html_names::kOpenAttr)
? kExpandedExpanded
: kExpandedCollapsed;
}
}
bool expanded = false;
if (AriaBooleanAttribute(html_names::kAriaExpandedAttr, &expanded)) {
return expanded ? kExpandedExpanded : kExpandedCollapsed;
}
return kExpandedUndefined;
}
bool AXNodeObject::IsRequired() const {
auto* form_control = DynamicTo<HTMLFormControlElement>(GetNode());
if (form_control && form_control->IsRequired())
return true;
if (IsAriaAttributeTrue(html_names::kAriaRequiredAttr)) {
return true;
}
return false;
}
bool AXNodeObject::CanvasHasFallbackContent() const {
if (IsDetached())
return false;
Node* node = GetNode();
return IsA<HTMLCanvasElement>(node) && node->hasChildren();
}
int AXNodeObject::HeadingLevel() const {
// headings can be in block flow and non-block flow
Node* node = GetNode();
if (!node)
return 0;
if (RoleValue() == ax::mojom::blink::Role::kHeading) {
int32_t level;
if (AriaIntAttribute(html_names::kAriaLevelAttr, &level)) {
if (level >= 1 && level <= 9) {
return level;
}
}
}
auto* element = DynamicTo<HTMLElement>(node);
if (!element)
return 0;
if (element->HasTagName(html_names::kH1Tag))
return 1 + element->GetComputedHeadingOffset(/*max_offset=*/8);
if (element->HasTagName(html_names::kH2Tag))
return 2 + element->GetComputedHeadingOffset(/*max_offset=*/7);
if (element->HasTagName(html_names::kH3Tag))
return 3 + element->GetComputedHeadingOffset(/*max_offset=*/6);
if (element->HasTagName(html_names::kH4Tag))
return 4 + element->GetComputedHeadingOffset(/*max_offset=*/5);
if (element->HasTagName(html_names::kH5Tag))
return 5 + element->GetComputedHeadingOffset(/*max_offset=*/4);
if (element->HasTagName(html_names::kH6Tag))
return 6 + element->GetComputedHeadingOffset(/*max_offset=*/3);
if (RoleValue() == ax::mojom::blink::Role::kHeading)
return kDefaultHeadingLevel;
// TODO(accessibility) For kDisclosureTriangle, kDisclosureTriangleGrouping,
// if IsAccessibilityExposeSummaryAsHeadingEnabled(), we should expose
// a default heading level that makes sense in the context of the document.
// Will likely be easier to do on the browser side.
if (ui::IsHeading(RoleValue())) {
return 5;
}
return 0;
}
unsigned AXNodeObject::HierarchicalLevel() const {
Element* element = GetElement();
if (!element)
return 0;
int32_t level;
if (AriaIntAttribute(html_names::kAriaLevelAttr, &level)) {
if (level >= 1)
return level;
}
// Helper lambda for calculating hierarchical levels by counting ancestor
// nodes that match a target role.
auto accumulateLevel = [&](int initial_level,
ax::mojom::blink::Role target_role) {
int level = initial_level;
for (AXObject* parent = ParentObject(); parent;
parent = parent->ParentObject()) {
if (parent->RoleValue() == target_role)
level++;
}
return level;
};
switch (RoleValue()) {
case ax::mojom::blink::Role::kComment:
// Comment: level is based on counting comment ancestors until the root.
return accumulateLevel(1, ax::mojom::blink::Role::kComment);
case ax::mojom::blink::Role::kListItem:
level = accumulateLevel(0, ax::mojom::blink::Role::kList);
// When level count is 0 due to this list item not having an ancestor of
// Role::kList, not nested in list groups, this list item has a level
// of 1.
return level == 0 ? 1 : level;
case ax::mojom::blink::Role::kTabList:
return accumulateLevel(1, ax::mojom::blink::Role::kTabList);
case ax::mojom::blink::Role::kTreeItem: {
// Hierarchy leveling starts at 1, to match the aria-level spec.
// We measure tree hierarchy by the number of groups that the item is
// within.
level = 1;
for (AXObject* parent = ParentObject(); parent;
parent = parent->ParentObject()) {
ax::mojom::blink::Role parent_role = parent->RoleValue();
if (parent_role == ax::mojom::blink::Role::kGroup)
level++;
else if (parent_role == ax::mojom::blink::Role::kTree)
break;
}
return level;
}
default:
return 0;
}
}
String AXNodeObject::AutoComplete() const {
// Check cache for auto complete state.
if (AXObjectCache().GetAutofillSuggestionAvailability(AXObjectID()) ==
WebAXAutofillSuggestionAvailability::kAutocompleteAvailable) {
return "list";
}
if (IsAtomicTextField() || IsARIATextField()) {
const AtomicString& aria_auto_complete =
AriaTokenAttribute(html_names::kAriaAutocompleteAttr);
// Illegal values must be passed through, according to CORE-AAM.
if (aria_auto_complete) {
return aria_auto_complete == "none" ? String()
: aria_auto_complete.LowerASCII();
;
}
}
if (auto* input = DynamicTo<HTMLInputElement>(GetNode())) {
if (input->DataList())
return "list";
}
return String();
}
// TODO(nektar): Consider removing this method in favor of
// AXInlineTextBox::GetDocumentMarkers, or add document markers to the tree data
// instead of nodes objects.
void AXNodeObject::SerializeMarkerAttributes(ui::AXNodeData* node_data) const {
if (!GetNode() || !GetDocument() || !GetDocument()->View())
return;
auto* text_node = DynamicTo<Text>(GetNode());
if (!text_node)
return;
std::vector<int32_t> marker_types;
std::vector<int32_t> highlight_types;
std::vector<int32_t> marker_starts;
std::vector<int32_t> marker_ends;
// First use ARIA markers for spelling/grammar if available.
std::optional<DocumentMarker::MarkerType> aria_marker_type =
GetAriaSpellingOrGrammarMarker();
if (aria_marker_type) {
AXRange range = AXRange::RangeOfContents(*this);
marker_types.push_back(ToAXMarkerType(aria_marker_type.value()));
marker_starts.push_back(range.Start().TextOffset());
marker_ends.push_back(range.End().TextOffset());
}
DocumentMarkerController& marker_controller = GetDocument()->Markers();
const DocumentMarker::MarkerTypes markers_used_by_accessibility(
DocumentMarker::kSpelling | DocumentMarker::kGrammar |
DocumentMarker::kTextMatch | DocumentMarker::kActiveSuggestion |
DocumentMarker::kSuggestion | DocumentMarker::kTextFragment |
DocumentMarker::kCustomHighlight);
const DocumentMarkerVector markers =
marker_controller.MarkersFor(*text_node, markers_used_by_accessibility);
for (const DocumentMarker* marker : markers) {
if (aria_marker_type == marker->GetType())
continue;
const Position start_position(*GetNode(), marker->StartOffset());
const Position end_position(*GetNode(), marker->EndOffset());
if (!start_position.IsValidFor(*GetDocument()) ||
!end_position.IsValidFor(*GetDocument())) {
continue;
}
int32_t highlight_type =
static_cast<int32_t>(ax::mojom::blink::HighlightType::kNone);
if (marker->GetType() == DocumentMarker::kCustomHighlight) {
const auto& highlight_marker = To<CustomHighlightMarker>(*marker);
highlight_type =
ToAXHighlightType(highlight_marker.GetHighlight()->type());
}
marker_types.push_back(ToAXMarkerType(marker->GetType()));
highlight_types.push_back(static_cast<int32_t>(highlight_type));
auto start_pos = AXPosition::FromPosition(
start_position, AXObjectCache(), TextAffinity::kDownstream,
AXPositionAdjustmentBehavior::kMoveLeft);
auto end_pos = AXPosition::FromPosition(
end_position, AXObjectCache(), TextAffinity::kDownstream,
AXPositionAdjustmentBehavior::kMoveRight);
marker_starts.push_back(start_pos.TextOffset());
marker_ends.push_back(end_pos.TextOffset());
}
if (marker_types.empty())
return;
node_data->AddIntListAttribute(
ax::mojom::blink::IntListAttribute::kMarkerTypes, marker_types);
node_data->AddIntListAttribute(
ax::mojom::blink::IntListAttribute::kHighlightTypes, highlight_types);
node_data->AddIntListAttribute(
ax::mojom::blink::IntListAttribute::kMarkerStarts, marker_starts);
node_data->AddIntListAttribute(
ax::mojom::blink::IntListAttribute::kMarkerEnds, marker_ends);
}
ax::mojom::blink::ListStyle AXNodeObject::GetListStyle() const {
const LayoutObject* layout_object = GetLayoutObject();
if (!layout_object) {
return AXObject::GetListStyle();
}
const ComputedStyle* computed_style = layout_object->Style();
if (!computed_style) {
return AXObject::GetListStyle();
}
const StyleImage* style_image = computed_style->ListStyleImage();
if (style_image && !style_image->ErrorOccurred()) {
return ax::mojom::blink::ListStyle::kImage;
}
if (RuntimeEnabledFeatures::CSSAtRuleCounterStyleSpeakAsDescriptorEnabled()) {
if (!computed_style->ListStyleType()) {
return ax::mojom::blink::ListStyle::kNone;
}
if (computed_style->ListStyleType()->IsString()) {
return ax::mojom::blink::ListStyle::kOther;
}
DCHECK(computed_style->ListStyleType()->IsCounterStyle());
const CounterStyle& counter_style =
ListMarker::GetCounterStyle(*GetDocument(), *computed_style);
switch (counter_style.EffectiveSpeakAs()) {
case CounterStyleSpeakAs::kBullets: {
// See |ua_counter_style_map.cc| for predefined symbolic counter styles.
UChar symbol = counter_style.GenerateTextAlternative(0)[0];
switch (symbol) {
case 0x2022:
return ax::mojom::blink::ListStyle::kDisc;
case 0x25E6:
return ax::mojom::blink::ListStyle::kCircle;
case 0x25A0:
return ax::mojom::blink::ListStyle::kSquare;
default:
return ax::mojom::blink::ListStyle::kOther;
}
}
case CounterStyleSpeakAs::kNumbers:
return ax::mojom::blink::ListStyle::kNumeric;
case CounterStyleSpeakAs::kWords:
return ax::mojom::blink::ListStyle::kOther;
case CounterStyleSpeakAs::kAuto:
case CounterStyleSpeakAs::kReference:
NOTREACHED();
}
}
switch (ListMarker::GetListStyleCategory(*GetDocument(), *computed_style)) {
case ListMarker::ListStyleCategory::kNone:
return ax::mojom::blink::ListStyle::kNone;
case ListMarker::ListStyleCategory::kSymbol: {
const AtomicString& counter_style_name =
computed_style->ListStyleType()->GetCounterStyleName();
if (counter_style_name == keywords::kDisc) {
return ax::mojom::blink::ListStyle::kDisc;
}
if (counter_style_name == keywords::kCircle) {
return ax::mojom::blink::ListStyle::kCircle;
}
if (counter_style_name == keywords::kSquare) {
return ax::mojom::blink::ListStyle::kSquare;
}
return ax::mojom::blink::ListStyle::kOther;
}
case ListMarker::ListStyleCategory::kLanguage: {
const AtomicString& counter_style_name =
computed_style->ListStyleType()->GetCounterStyleName();
if (counter_style_name == keywords::kDecimal) {
return ax::mojom::blink::ListStyle::kNumeric;
}
if (counter_style_name == "decimal-leading-zero") {
// 'decimal-leading-zero' may be overridden by custom counter styles. We
// return kNumeric only when we are using the predefined counter style.
if (ListMarker::GetCounterStyle(*GetDocument(), *computed_style)
.IsPredefined()) {
return ax::mojom::blink::ListStyle::kNumeric;
}
}
return ax::mojom::blink::ListStyle::kOther;
}
case ListMarker::ListStyleCategory::kStaticString:
return ax::mojom::blink::ListStyle::kOther;
}
}
AXObject* AXNodeObject::InPageLinkTarget() const {
if (!IsLink() || !GetDocument())
return AXObject::InPageLinkTarget();
const Element* anchor = AnchorElement();
if (!anchor)
return AXObject::InPageLinkTarget();
KURL link_url = anchor->HrefURL();
if (!link_url.IsValid())
return AXObject::InPageLinkTarget();
KURL document_url = GetDocument()->Url();
if (!document_url.IsValid() ||
!EqualIgnoringFragmentIdentifier(document_url, link_url)) {
return AXObject::InPageLinkTarget();
}
String fragment = link_url.FragmentIdentifier().ToString();
TreeScope& tree_scope = anchor->GetTreeScope();
Node* target = tree_scope.FindAnchor(fragment);
AXObject* ax_target = AXObjectCache().Get(target);
if (!ax_target || !IsPotentialInPageLinkTarget(*ax_target->GetNode()))
return AXObject::InPageLinkTarget();
#if DCHECK_IS_ON()
// Link targets always have an element, unless it is the document itself,
// e.g. via <a href="#">.
DCHECK(ax_target->IsWebArea() || ax_target->GetElement())
<< "The link target is expected to be a document or an element: "
<< ax_target << "\n* URL fragment = " << fragment;
#endif
// Usually won't be ignored, but could be e.g. if aria-hidden.
if (ax_target->IsIgnored())
return nullptr;
return ax_target;
}
const AtomicString& AXNodeObject::EffectiveTarget() const {
// The "target" attribute defines the target browser context and is supported
// on <a>, <area>, <base>, and <form>. Valid values are: "frame_name", "self",
// "blank", "top", and "parent", where "frame_name" is the value of the "name"
// attribute on any enclosing iframe.
//
// <area> is a subclass of <a>, while <base> provides the document's base
// target that any <a>'s or any <area>'s target can override.
// `HtmlAnchorElement::GetEffectiveTarget()` will take <base> into account.
//
// <form> is out of scope, because it affects the target to which the form is
// submitted, and could also be overridden by a "formTarget" attribute on e.g.
// a form's submit button. However, screen reader users have no need to know
// to which target (browser context) a form would be submitted.
const auto* anchor = DynamicTo<HTMLAnchorElementBase>(GetNode());
if (anchor) {
const AtomicString self_value("_self");
const AtomicString& effective_target = anchor->GetEffectiveTarget();
if (effective_target != self_value) {
return anchor->GetEffectiveTarget();
}
}
return AXObject::EffectiveTarget();
}
AccessibilityOrientation AXNodeObject::Orientation() const {
const AtomicString& aria_orientation =
AriaTokenAttribute(html_names::kAriaOrientationAttr);
AccessibilityOrientation orientation = kAccessibilityOrientationUndefined;
if (EqualIgnoringASCIICase(aria_orientation, "horizontal"))
orientation = kAccessibilityOrientationHorizontal;
else if (EqualIgnoringASCIICase(aria_orientation, "vertical"))
orientation = kAccessibilityOrientationVertical;
switch (RoleValue()) {
case ax::mojom::blink::Role::kListBox:
case ax::mojom::blink::Role::kMenu:
case ax::mojom::blink::Role::kScrollBar:
case ax::mojom::blink::Role::kTree:
if (orientation == kAccessibilityOrientationUndefined)
orientation = kAccessibilityOrientationVertical;
return orientation;
case ax::mojom::blink::Role::kMenuBar:
case ax::mojom::blink::Role::kSlider:
case ax::mojom::blink::Role::kSplitter:
case ax::mojom::blink::Role::kTabList:
case ax::mojom::blink::Role::kToolbar:
if (orientation == kAccessibilityOrientationUndefined)
orientation = kAccessibilityOrientationHorizontal;
return orientation;
case ax::mojom::blink::Role::kComboBoxGrouping:
case ax::mojom::blink::Role::kComboBoxMenuButton:
case ax::mojom::blink::Role::kRadioGroup:
case ax::mojom::blink::Role::kTreeGrid:
return orientation;
default:
return AXObject::Orientation();
}
}
// According to the standard, the figcaption should only be the first or
// last child: https://html.spec.whatwg.org/#the-figcaption-element
AXObject* AXNodeObject::GetChildFigcaption() const {
AXObject* child = FirstChildIncludingIgnored();
if (!child)
return nullptr;
if (child->RoleValue() == ax::mojom::blink::Role::kFigcaption)
return child;
child = LastChildIncludingIgnored();
if (child->RoleValue() == ax::mojom::blink::Role::kFigcaption)
return child;
return nullptr;
}
AXObject::AXObjectVector AXNodeObject::RadioButtonsInGroup() const {
AXObjectVector radio_buttons;
if (!node_ || RoleValue() != ax::mojom::blink::Role::kRadioButton)
return radio_buttons;
if (auto* node_radio_button = DynamicTo<HTMLInputElement>(node_.Get())) {
HeapVector<Member<HTMLInputElement>> html_radio_buttons =
FindAllRadioButtonsWithSameName(node_radio_button);
for (HTMLInputElement* radio_button : html_radio_buttons) {
AXObject* ax_radio_button = AXObjectCache().Get(radio_button);
if (ax_radio_button)
radio_buttons.push_back(ax_radio_button);
}
return radio_buttons;
}
// If the immediate parent is a radio group, return all its children that are
// radio buttons.
AXObject* parent = ParentObjectUnignored();
if (parent && parent->RoleValue() == ax::mojom::blink::Role::kRadioGroup) {
for (AXObject* child : parent->UnignoredChildrenSlow()) {
DCHECK(child);
if (child->RoleValue() == ax::mojom::blink::Role::kRadioButton &&
child->IsIncludedInTree()) {
radio_buttons.push_back(child);
}
}
}
return radio_buttons;
}
// static
HeapVector<Member<HTMLInputElement>>
AXNodeObject::FindAllRadioButtonsWithSameName(HTMLInputElement* radio_button) {
HeapVector<Member<HTMLInputElement>> all_radio_buttons;
if (!radio_button ||
radio_button->FormControlType() != FormControlType::kInputRadio) {
return all_radio_buttons;
}
constexpr bool kTraverseForward = true;
constexpr bool kTraverseBackward = false;
HTMLInputElement* first_radio_button = radio_button;
do {
radio_button = RadioInputType::NextRadioButtonInGroup(first_radio_button,
kTraverseBackward);
if (radio_button)
first_radio_button = radio_button;
} while (radio_button);
HTMLInputElement* next_radio_button = first_radio_button;
do {
all_radio_buttons.push_back(next_radio_button);
next_radio_button = RadioInputType::NextRadioButtonInGroup(
next_radio_button, kTraverseForward);
} while (next_radio_button);
return all_radio_buttons;
}
ax::mojom::blink::WritingDirection AXNodeObject::GetTextDirection() const {
if (!GetLayoutObject())
return AXObject::GetTextDirection();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXObject::GetTextDirection();
switch (style->GetWritingDirection().InlineEnd()) {
case PhysicalDirection::kRight:
return ax::mojom::blink::WritingDirection::kLtr;
case PhysicalDirection::kLeft:
return ax::mojom::blink::WritingDirection::kRtl;
case PhysicalDirection::kDown:
return ax::mojom::blink::WritingDirection::kTtb;
case PhysicalDirection::kUp:
return ax::mojom::blink::WritingDirection::kBtt;
}
NOTREACHED();
}
ax::mojom::blink::TextPosition AXNodeObject::GetTextPositionFromRole() const {
// Check for role="subscript" or role="superscript" on the element, or if
// static text, on the containing element.
AXObject* obj = nullptr;
if (RoleValue() == ax::mojom::blink::Role::kStaticText)
obj = ParentObject();
else
obj = const_cast<AXNodeObject*>(this);
if (obj->RoleValue() == ax::mojom::blink::Role::kSubscript)
return ax::mojom::blink::TextPosition::kSubscript;
if (obj->RoleValue() == ax::mojom::blink::Role::kSuperscript)
return ax::mojom::blink::TextPosition::kSuperscript;
if (!GetLayoutObject() || !GetLayoutObject()->IsInline())
return ax::mojom::blink::TextPosition::kNone;
// We could have an inline element which descends from a subscript or
// superscript.
if (auto* parent = obj->ParentObjectUnignored())
return static_cast<AXNodeObject*>(parent)->GetTextPositionFromRole();
return ax::mojom::blink::TextPosition::kNone;
}
ax::mojom::blink::TextPosition AXNodeObject::GetTextPosition() const {
if (GetNode()) {
const auto& text_position = GetTextPositionFromRole();
if (text_position != ax::mojom::blink::TextPosition::kNone)
return text_position;
}
if (!GetLayoutObject())
return AXObject::GetTextPosition();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXObject::GetTextPosition();
switch (style->VerticalAlign()) {
case EVerticalAlign::kBaseline:
case EVerticalAlign::kMiddle:
case EVerticalAlign::kTextTop:
case EVerticalAlign::kTextBottom:
case EVerticalAlign::kTop:
case EVerticalAlign::kBottom:
case EVerticalAlign::kBaselineMiddle:
case EVerticalAlign::kLength:
return AXObject::GetTextPosition();
case EVerticalAlign::kSub:
return ax::mojom::blink::TextPosition::kSubscript;
case EVerticalAlign::kSuper:
return ax::mojom::blink::TextPosition::kSuperscript;
}
}
void AXNodeObject::GetTextStyleAndTextDecorationStyle(
int32_t* text_style,
ax::mojom::blink::TextDecorationStyle* text_overline_style,
ax::mojom::blink::TextDecorationStyle* text_strikethrough_style,
ax::mojom::blink::TextDecorationStyle* text_underline_style) const {
if (!GetLayoutObject()) {
AXObject::GetTextStyleAndTextDecorationStyle(
text_style, text_overline_style, text_strikethrough_style,
text_underline_style);
return;
}
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style) {
AXObject::GetTextStyleAndTextDecorationStyle(
text_style, text_overline_style, text_strikethrough_style,
text_underline_style);
return;
}
*text_style = 0;
*text_overline_style = ax::mojom::blink::TextDecorationStyle::kNone;
*text_strikethrough_style = ax::mojom::blink::TextDecorationStyle::kNone;
*text_underline_style = ax::mojom::blink::TextDecorationStyle::kNone;
if (style->GetFontWeight() == kBoldWeightValue) {
*text_style |= TextStyleFlag(ax::mojom::blink::TextStyle::kBold);
}
if (style->GetFontDescription().Style() == kItalicSlopeValue) {
*text_style |= TextStyleFlag(ax::mojom::blink::TextStyle::kItalic);
}
for (const auto& decoration : style->AppliedTextDecorations()) {
if (EnumHasFlags(decoration.Lines(), TextDecorationLine::kOverline)) {
*text_style |= TextStyleFlag(ax::mojom::blink::TextStyle::kOverline);
*text_overline_style =
TextDecorationStyleToAXTextDecorationStyle(decoration.Style());
}
if (EnumHasFlags(decoration.Lines(), TextDecorationLine::kLineThrough)) {
*text_style |= TextStyleFlag(ax::mojom::blink::TextStyle::kLineThrough);
*text_strikethrough_style =
TextDecorationStyleToAXTextDecorationStyle(decoration.Style());
}
if (EnumHasFlags(decoration.Lines(), TextDecorationLine::kUnderline)) {
*text_style |= TextStyleFlag(ax::mojom::blink::TextStyle::kUnderline);
*text_underline_style =
TextDecorationStyleToAXTextDecorationStyle(decoration.Style());
}
}
}
ax::mojom::blink::TextAlign AXNodeObject::GetTextAlign() const {
// Object attributes are not applied to text objects.
if (IsTextObject() || !GetLayoutObject())
return ax::mojom::blink::TextAlign::kNone;
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return ax::mojom::blink::TextAlign::kNone;
switch (style->GetTextAlign()) {
case ETextAlign::kLeft:
case ETextAlign::kWebkitLeft:
case ETextAlign::kStart:
return ax::mojom::blink::TextAlign::kLeft;
case ETextAlign::kRight:
case ETextAlign::kWebkitRight:
case ETextAlign::kEnd:
return ax::mojom::blink::TextAlign::kRight;
case ETextAlign::kCenter:
case ETextAlign::kWebkitCenter:
return ax::mojom::blink::TextAlign::kCenter;
case ETextAlign::kJustify:
return ax::mojom::blink::TextAlign::kJustify;
case ETextAlign::kMatchParent:
return style->IsLeftToRightDirection()
? ax::mojom::blink::TextAlign::kLeft
: ax::mojom::blink::TextAlign::kRight;
}
}
float AXNodeObject::GetTextIndent() const {
// Text-indent applies to lines or blocks, but not text.
if (IsTextObject() || !GetLayoutObject())
return 0.0f;
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return 0.0f;
const blink::LayoutBlock* layout_block =
GetLayoutObject()->InclusiveContainingBlock();
if (!layout_block)
return 0.0f;
float text_indent = layout_block->TextIndentOffset().ToFloat();
return text_indent / kCssPixelsPerMillimeter;
}
String AXNodeObject::ImageDataUrl(const gfx::Size& max_size) const {
Node* node = GetNode();
if (!node)
return String();
ImageBitmapOptions* options = ImageBitmapOptions::Create();
ImageBitmap* image_bitmap = nullptr;
if (auto* image = DynamicTo<HTMLImageElement>(node)) {
image_bitmap =
MakeGarbageCollected<ImageBitmap>(image, std::nullopt, options);
} else if (auto* canvas = DynamicTo<HTMLCanvasElement>(node)) {
image_bitmap =
MakeGarbageCollected<ImageBitmap>(canvas, std::nullopt, options);
} else if (auto* video = DynamicTo<HTMLVideoElement>(node)) {
image_bitmap =
MakeGarbageCollected<ImageBitmap>(video, std::nullopt, options);
}
if (!image_bitmap)
return String();
scoped_refptr<StaticBitmapImage> bitmap_image = image_bitmap->BitmapImage();
if (!bitmap_image)
return String();
sk_sp<SkImage> image =
bitmap_image->PaintImageForCurrentFrame().GetSwSkImage();
if (!image || image->width() <= 0 || image->height() <= 0)
return String();
// Determine the width and height of the output image, using a proportional
// scale factor such that it's no larger than |maxSize|, if |maxSize| is not
// empty. It only resizes the image to be smaller (if necessary), not
// larger.
float x_scale =
max_size.width() ? max_size.width() * 1.0 / image->width() : 1.0;
float y_scale =
max_size.height() ? max_size.height() * 1.0 / image->height() : 1.0;
float scale = std::min(x_scale, y_scale);
if (scale >= 1.0)
scale = 1.0;
int width = std::round(image->width() * scale);
int height = std::round(image->height() * scale);
// Draw the image into a bitmap in native format.
SkBitmap bitmap;
SkPixmap unscaled_pixmap;
if (scale == 1.0 && image->peekPixels(&unscaled_pixmap)) {
bitmap.installPixels(unscaled_pixmap);
} else {
bitmap.allocPixels(
SkImageInfo::MakeN32(width, height, kPremul_SkAlphaType));
SkCanvas canvas(bitmap, SkSurfaceProps{});
canvas.clear(SK_ColorTRANSPARENT);
canvas.drawImageRect(image, SkRect::MakeIWH(width, height),
SkSamplingOptions());
}
// Copy the bits into a buffer in RGBA_8888 unpremultiplied format
// for encoding.
SkImageInfo info = SkImageInfo::Make(width, height, kRGBA_8888_SkColorType,
kUnpremul_SkAlphaType);
size_t row_bytes = info.minRowBytes();
Vector<char> pixel_storage(
base::checked_cast<wtf_size_t>(info.computeByteSize(row_bytes)));
SkPixmap pixmap(info, pixel_storage.data(), row_bytes);
if (!SkImages::RasterFromBitmap(bitmap)->readPixels(pixmap, 0, 0)) {
return String();
}
// Encode as a PNG and return as a data url.
std::unique_ptr<ImageDataBuffer> buffer = ImageDataBuffer::Create(pixmap);
if (!buffer)
return String();
return buffer->ToDataURL(kMimeTypePng, 1.0);
}
const AtomicString& AXNodeObject::AccessKey() const {
auto* element = DynamicTo<Element>(GetNode());
if (!element)
return g_null_atom;
return element->FastGetAttribute(html_names::kAccesskeyAttr);
}
RGBA32 AXNodeObject::ColorValue() const {
auto* input = DynamicTo<HTMLInputElement>(GetNode());
if (!input || !IsColorWell())
return AXObject::ColorValue();
const AtomicString& type = input->getAttribute(kTypeAttr);
if (!EqualIgnoringASCIICase(type, "color"))
return AXObject::ColorValue();
// HTMLInputElement::Value always returns a string parseable by Color.
Color color;
bool success = color.SetFromString(input->Value());
DCHECK(success);
return color.Rgb();
}
RGBA32 AXNodeObject::BackgroundColor() const {
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object)
return Color::kTransparent.Rgb();
if (IsA<Document>(GetNode())) {
LocalFrameView* view = DocumentFrameView();
if (view)
return view->BaseBackgroundColor().Rgb();
else
return Color::kWhite.Rgb();
}
const ComputedStyle* style = layout_object->Style();
if (!style || !style->HasBackground())
return Color::kTransparent.Rgb();
return style->VisitedDependentColor(GetCSSPropertyBackgroundColor()).Rgb();
}
RGBA32 AXNodeObject::GetColor() const {
if (!GetLayoutObject() || IsColorWell())
return AXObject::GetColor();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXObject::GetColor();
Color color = style->VisitedDependentColor(GetCSSPropertyColor());
return color.Rgb();
}
const AtomicString& AXNodeObject::ComputedFontFamily() const {
if (!GetLayoutObject())
return AXObject::ComputedFontFamily();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXObject::ComputedFontFamily();
const FontDescription& font_description = style->GetFontDescription();
return font_description.FirstFamily().FamilyName();
}
String AXNodeObject::FontFamilyForSerialization() const {
if (!GetLayoutObject())
return AXObject::FontFamilyForSerialization();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXObject::FontFamilyForSerialization();
const SimpleFontData* primary_font = style->GetFont()->PrimaryFont();
if (!primary_font)
return AXObject::FontFamilyForSerialization();
// Note that repeatedly querying this can be expensive - only use this when
// serializing. For other comparisons consider using `ComputedFontFamily`.
return primary_font->PlatformData().FontFamilyName();
}
// Blink font size is provided in pixels.
// Platform APIs may convert to another unit (IA2 converts to points).
float AXNodeObject::FontSize() const {
if (!GetLayoutObject())
return AXObject::FontSize();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXObject::FontSize();
// Font size should not be affected by scale transform or page zoom, because
// users of authoring tools may want to check that their text is formatted
// with the font size they expected.
// E.g. use SpecifiedFontSize() instead of ComputedFontSize(), and do not
// multiply by style->Scale()->Transform()->Y();
return style->SpecifiedFontSize();
}
float AXNodeObject::FontWeight() const {
if (!GetLayoutObject())
return AXObject::FontWeight();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXObject::FontWeight();
return style->GetFontWeight();
}
ax::mojom::blink::AriaCurrentState AXNodeObject::GetAriaCurrentState() const {
const AtomicString& attribute_value =
AriaTokenAttribute(html_names::kAriaCurrentAttr);
if (attribute_value.IsNull()) {
if (RuntimeEnabledFeatures::CSSScrollTargetGroupAriaCurrentEnabled()) {
// If aria-current is not set, check if the anchor element is selected
// in a scroll marker group (it's now a :target-current). If so, set
// aria-current="true" on the element.
if (auto* anchor_element = DynamicTo<HTMLAnchorElement>(GetNode())) {
if (ScrollMarkerGroupData* data =
anchor_element->GetScrollTargetGroupContainerData()) {
if (data->Selected() == anchor_element) {
return ax::mojom::blink::AriaCurrentState::kTrue;
}
}
}
}
return ax::mojom::blink::AriaCurrentState::kNone;
}
if (EqualIgnoringASCIICase(attribute_value, "false")) {
return ax::mojom::blink::AriaCurrentState::kFalse;
}
if (EqualIgnoringASCIICase(attribute_value, "page")) {
return ax::mojom::blink::AriaCurrentState::kPage;
}
if (EqualIgnoringASCIICase(attribute_value, "step")) {
return ax::mojom::blink::AriaCurrentState::kStep;
}
if (EqualIgnoringASCIICase(attribute_value, "location")) {
return ax::mojom::blink::AriaCurrentState::kLocation;
}
if (EqualIgnoringASCIICase(attribute_value, "date")) {
return ax::mojom::blink::AriaCurrentState::kDate;
}
if (EqualIgnoringASCIICase(attribute_value, "time")) {
return ax::mojom::blink::AriaCurrentState::kTime;
}
// An unknown value should return true.
return ax::mojom::blink::AriaCurrentState::kTrue;
}
ax::mojom::blink::InvalidState AXNodeObject::GetInvalidState() const {
// First check aria-invalid.
if (const AtomicString& attribute_value =
AriaTokenAttribute(html_names::kAriaInvalidAttr)) {
// aria-invalid="false".
if (EqualIgnoringASCIICase(attribute_value, "false")) {
return ax::mojom::blink::InvalidState::kFalse;
}
// In most cases, aria-invalid="spelling"| "grammar" are used on inline text
// elements, and are exposed via Markers() as if they are native errors.
// Therefore, they are exposed as InvalidState:kNone here in order to avoid
// exposing the state twice, and to prevent superfluous "invalid"
// announcements in some screen readers.
// On text fields, they are simply exposed as if aria-invalid="true".
if (EqualIgnoringASCIICase(attribute_value, "spelling") ||
EqualIgnoringASCIICase(attribute_value, "grammar")) {
return RoleValue() == ax::mojom::blink::Role::kTextField
? ax::mojom::blink::InvalidState::kTrue
: ax::mojom::blink::InvalidState::kNone;
}
// Any other non-empty value is considered true.
if (!attribute_value.empty()) {
return ax::mojom::blink::InvalidState::kTrue;
}
}
// Next check for native the invalid state.
if (GetElement()) {
ListedElement* form_control = ListedElement::From(*GetElement());
if (form_control) {
return IsValidFormControl(form_control)
? ax::mojom::blink::InvalidState::kFalse
: ax::mojom::blink::InvalidState::kTrue;
}
}
return AXObject::GetInvalidState();
}
bool AXNodeObject::IsValidFormControl(ListedElement* form_control) const {
// If the control is marked with a custom error, the form control is invalid.
if (form_control->CustomError())
return false;
// If the form control checks for validity, and has passed the checks,
// then consider it valid.
if (form_control->IsNotCandidateOrValid())
return true;
// The control is invalid, as far as CSS is concerned.
// However, we ignore a failed check inside of an empty required text field,
// in order to avoid redundant verbalizations (screen reader already says
// required).
if (IsAtomicTextField() && IsRequired() && GetValueForControl().length() == 0)
return true;
return false;
}
int AXNodeObject::PosInSet() const {
// A <select size=1> exposes posinset as the index of the selected option.
if (RoleValue() == ax::mojom::blink::Role::kComboBoxSelect) {
if (auto* select_element = DynamicTo<HTMLSelectElement>(*GetNode())) {
return 1 + select_element->selectedIndex();
}
}
if (SupportsARIASetSizeAndPosInSet()) {
int32_t pos_in_set;
if (AriaIntAttribute(html_names::kAriaPosinsetAttr, &pos_in_set)) {
return pos_in_set;
}
}
return 0;
}
int AXNodeObject::SetSize() const {
if (auto* select_element = DynamicTo<HTMLSelectElement>(GetNode())) {
return static_cast<int>(select_element->length());
}
if (RoleValue() == ax::mojom::blink::Role::kMenuListPopup) {
return ParentObject()->SetSize();
}
if (SupportsARIASetSizeAndPosInSet()) {
int32_t set_size;
if (AriaIntAttribute(html_names::kAriaSetsizeAttr, &set_size)) {
return set_size;
}
}
return 0;
}
bool AXNodeObject::ValueForRange(float* out_value) const {
float value_now;
if (AriaFloatAttribute(html_names::kAriaValuenowAttr, &value_now)) {
// Adjustment when the aria-valuenow is less than aria-valuemin or greater
// than the aria-valuemax value.
// See https://w3c.github.io/aria/#authorErrorDefaultValuesTable.
float min_value, max_value;
if (MinValueForRange(&min_value)) {
if (value_now < min_value) {
*out_value = min_value;
return true;
}
}
if (MaxValueForRange(&max_value)) {
if (value_now > max_value) {
*out_value = max_value;
return true;
}
}
*out_value = value_now;
return true;
}
if (IsNativeSlider() || IsNativeSpinButton()) {
*out_value = To<HTMLInputElement>(*GetNode()).valueAsNumber();
return std::isfinite(*out_value);
}
if (auto* meter = DynamicTo<HTMLMeterElement>(GetNode())) {
*out_value = meter->value();
return true;
}
// In ARIA 1.1, default values for aria-valuenow were changed as below.
// - meter: A value matching the implicit or explicitly set aria-valuemin.
// - scrollbar, slider : half way between aria-valuemin and aria-valuemax
// - separator : 50
// - spinbutton : 0
switch (RawAriaRole()) {
case ax::mojom::blink::Role::kScrollBar:
case ax::mojom::blink::Role::kSlider: {
float min_value, max_value;
if (MinValueForRange(&min_value) && MaxValueForRange(&max_value)) {
*out_value = (min_value + max_value) / 2.0f;
return true;
}
[[fallthrough]];
}
case ax::mojom::blink::Role::kSplitter: {
*out_value = 50.0f;
return true;
}
case ax::mojom::blink::Role::kMeter: {
float min_value;
if (MinValueForRange(&min_value)) {
*out_value = min_value;
return true;
}
[[fallthrough]];
}
case ax::mojom::blink::Role::kSpinButton: {
*out_value = 0.0f;
return true;
}
default:
break;
}
return false;
}
bool AXNodeObject::MaxValueForRange(float* out_value) const {
if (AriaFloatAttribute(html_names::kAriaValuemaxAttr, out_value)) {
return true;
}
if (IsNativeSlider() || IsNativeSpinButton()) {
*out_value = static_cast<float>(To<HTMLInputElement>(*GetNode()).Maximum());
return std::isfinite(*out_value);
}
if (auto* meter = DynamicTo<HTMLMeterElement>(GetNode())) {
*out_value = meter->max();
return true;
}
// In ARIA 1.1, default value of scrollbar, separator and slider
// for aria-valuemax were changed to 100. This change was made for
// progressbar in ARIA 1.2.
switch (RawAriaRole()) {
case ax::mojom::blink::Role::kMeter:
case ax::mojom::blink::Role::kProgressIndicator:
case ax::mojom::blink::Role::kScrollBar:
case ax::mojom::blink::Role::kSplitter:
case ax::mojom::blink::Role::kSlider: {
*out_value = 100.0f;
return true;
}
default:
break;
}
return false;
}
bool AXNodeObject::MinValueForRange(float* out_value) const {
if (AriaFloatAttribute(html_names::kAriaValueminAttr, out_value)) {
return true;
}
if (IsNativeSlider() || IsNativeSpinButton()) {
*out_value = static_cast<float>(To<HTMLInputElement>(*GetNode()).Minimum());
return std::isfinite(*out_value);
}
if (auto* meter = DynamicTo<HTMLMeterElement>(GetNode())) {
*out_value = meter->min();
return true;
}
// In ARIA 1.1, default value of scrollbar, separator and slider
// for aria-valuemin were changed to 0. This change was made for
// progressbar in ARIA 1.2.
switch (RawAriaRole()) {
case ax::mojom::blink::Role::kMeter:
case ax::mojom::blink::Role::kProgressIndicator:
case ax::mojom::blink::Role::kScrollBar:
case ax::mojom::blink::Role::kSplitter:
case ax::mojom::blink::Role::kSlider: {
*out_value = 0.0f;
return true;
}
default:
break;
}
return false;
}
bool AXNodeObject::StepValueForRange(float* out_value) const {
if (IsNativeSlider() || IsNativeSpinButton()) {
auto step_range =
To<HTMLInputElement>(*GetNode()).CreateStepRange(kRejectAny);
auto step = step_range.Step().ToString().ToFloat();
// Provide a step if ATs incrementing slider should move by step, otherwise
// AT will move by 5%.
// If there are too few allowed stops (< 20), incrementing/decrementing
// the slider by 5% could get stuck, and therefore the step is exposed.
// The step is also exposed if moving by 5% would cause intermittent
// behavior where sometimes the slider would alternate by 1 or 2 steps.
// Therefore the final decision is to use the step if there are
// less than stops in the slider, otherwise, move by 5%.
float max = step_range.Maximum().ToString().ToFloat();
float min = step_range.Minimum().ToString().ToFloat();
int num_stops = base::saturated_cast<int>((max - min) / step);
constexpr int kNumStopsForFivePercentRule = 40;
if (num_stops >= kNumStopsForFivePercentRule) {
// No explicit step, and the step is very small -- don't expose a step
// so that Talkback will move by 5% increments.
*out_value = 0.0f;
return false;
}
*out_value = step;
return std::isfinite(*out_value);
}
switch (RawAriaRole()) {
case ax::mojom::blink::Role::kScrollBar:
case ax::mojom::blink::Role::kSplitter:
case ax::mojom::blink::Role::kSlider: {
*out_value = 0.0f;
return true;
}
default:
break;
}
return false;
}
KURL AXNodeObject::Url() const {
if (IsLink()) // <area>, <link>, <html:a> or <svg:a>
return GetElement()->HrefURL();
if (IsWebArea()) {
DCHECK(GetDocument());
return GetDocument()->Url();
}
auto* html_image_element = DynamicTo<HTMLImageElement>(GetNode());
if (IsImage() && html_image_element) {
// Using ImageSourceURL handles both src and srcset.
String source_url = html_image_element->ImageSourceURL();
String stripped_image_source_url =
StripLeadingAndTrailingHTMLSpaces(source_url);
if (!stripped_image_source_url.empty())
return GetDocument()->CompleteURL(stripped_image_source_url);
}
if (IsInputImage())
return To<HTMLInputElement>(GetNode())->Src();
return KURL();
}
AXObject* AXNodeObject::ChooserPopup() const {
// When color & date chooser popups are visible, they can be found in the tree
// as a group child of the <input> control itself.
switch (native_role_) {
case ax::mojom::blink::Role::kColorWell:
case ax::mojom::blink::Role::kComboBoxSelect:
case ax::mojom::blink::Role::kDate:
case ax::mojom::blink::Role::kDateTime:
case ax::mojom::blink::Role::kInputTime:
case ax::mojom::blink::Role::kTextFieldWithComboBox: {
for (const auto& child : ChildrenIncludingIgnored()) {
if (IsA<Document>(child->GetNode())) {
return child.Get();
}
}
return nullptr;
}
default:
#if DCHECK_IS_ON()
for (const auto& child : ChildrenIncludingIgnored()) {
DCHECK(!IsA<Document>(child->GetNode()) ||
!child->ParentObject()->IsVisible())
<< "Chooser popup exists for " << native_role_
<< "\n* Child: " << child
<< "\n* Child's immediate parent: " << child->ParentObject();
}
#endif
return nullptr;
}
}
String AXNodeObject::GetValueForControl() const {
AXObjectSet visited;
return GetValueForControl(visited);
}
String AXNodeObject::GetValueForControl(AXObjectSet& visited) const {
// TODO(crbug.com/1165853): Remove this method completely and compute value on
// the browser side.
Node* node = GetNode();
if (!node)
return String();
if (const auto* select_element = DynamicTo<HTMLSelectElement>(*node)) {
if (!select_element->UsesMenuList())
return String();
// In most cases, we want to return what's actually displayed inside the
// <select> element on screen, unless there is an ARIA label overriding it.
int selected_index = select_element->SelectedListIndex();
const HeapVector<Member<HTMLElement>>& list_items =
select_element->GetListItems();
if (selected_index >= 0 &&
static_cast<wtf_size_t>(selected_index) < list_items.size()) {
const AtomicString& overridden_description = AriaAttribute(
*list_items[selected_index], html_names::kAriaLabelAttr);
if (!overridden_description.IsNull())
return overridden_description;
}
// If the author replaced the button by providing their own <button> on a
// customizable select, then use the text inside that button:
// https://github.com/openui/open-ui/issues/1117
if (select_element->IsAppearanceBase()) {
if (auto* button = select_element->SlottedButton()) {
if (AXObject* button_object = AXObjectCache().Get(button)) {
return button_object->TextFromDescendants(visited, nullptr, false);
}
}
}
// We don't retrieve the element's value attribute on purpose. The value
// attribute might be sanitized and might be different from what is actually
// displayed inside the <select> element on screen.
return select_element->InnerElement().GetInnerTextWithoutUpdate();
}
if (IsAtomicTextField()) {
// This is an "<input type=text>" or a "<textarea>": We should not simply
// return the "value" attribute because it might be sanitized in some input
// control types, e.g. email fields. If we do that, then "selectionStart"
// and "selectionEnd" indices will not match with the text in the sanitized
// value.
String inner_text = ToTextControl(*node).InnerEditorValue();
unsigned int unmasked_text_length = inner_text.length();
// If the inner text is empty, we return a null string to let the text
// alternative algorithm continue searching for an accessible name.
if (!unmasked_text_length) {
return String();
}
if (!IsPasswordFieldAndShouldHideValue())
return inner_text;
if (!GetLayoutObject())
return inner_text;
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return inner_text;
UChar mask_character = 0;
switch (style->TextSecurity()) {
case ETextSecurity::kNone:
break; // Fall through to the non-password branch.
case ETextSecurity::kDisc:
mask_character = uchar::kBullet;
break;
case ETextSecurity::kCircle:
mask_character = uchar::kWhiteBullet;
break;
case ETextSecurity::kSquare:
mask_character = uchar::kBlackSquare;
break;
}
if (!mask_character)
return inner_text;
StringBuilder masked_text;
masked_text.ReserveCapacity(unmasked_text_length);
for (unsigned int i = 0; i < unmasked_text_length; ++i)
masked_text.Append(mask_character);
return masked_text.ToString();
}
if (IsRangeValueSupported()) {
return AriaAttribute(html_names::kAriaValuetextAttr).GetString();
}
// Handle other HTML input elements that aren't text controls, like date and
// time controls, by returning their value converted to text, with the
// exception of checkboxes and radio buttons (which would return "on"), and
// buttons which will return their name.
// https://html.spec.whatwg.org/C/#dom-input-value
if (const auto* input = DynamicTo<HTMLInputElement>(node)) {
if (input->FormControlType() == FormControlType::kInputFile) {
return input->FileStatusText();
}
if (input->FormControlType() != FormControlType::kInputButton &&
input->FormControlType() != FormControlType::kInputCheckbox &&
input->FormControlType() != FormControlType::kInputImage &&
input->FormControlType() != FormControlType::kInputRadio &&
input->FormControlType() != FormControlType::kInputReset &&
input->FormControlType() != FormControlType::kInputSubmit) {
return input->Value();
}
}
if (RoleValue() == ax::mojom::blink::Role::kComboBoxMenuButton) {
// An ARIA combobox can get value from inner contents.
return TextFromDescendants(visited, nullptr, false);
}
return String();
}
String AXNodeObject::SlowGetValueForControlIncludingContentEditable() const {
AXObjectSet visited;
return SlowGetValueForControlIncludingContentEditable(visited);
}
String AXNodeObject::SlowGetValueForControlIncludingContentEditable(
AXObjectSet& visited) const {
if (IsNonAtomicTextField()) {
Element* element = GetElement();
return element ? element->GetInnerTextWithoutUpdate() : String();
}
return GetValueForControl(visited);
}
ax::mojom::blink::Role AXNodeObject::RawAriaRole() const {
return aria_role_;
}
ax::mojom::blink::HasPopup AXNodeObject::HasPopup() const {
auto* element = GetElement();
auto has_popup_from_attribute =
element ? HasPopupFromAttribute(*element) : std::nullopt;
if (has_popup_from_attribute) {
return *has_popup_from_attribute;
}
// ARIA 1.1 default value of haspopup for combobox is "listbox".
if (RoleValue() == ax::mojom::blink::Role::kComboBoxMenuButton ||
RoleValue() == ax::mojom::blink::Role::kTextFieldWithComboBox) {
return ax::mojom::blink::HasPopup::kListbox;
}
if (AXObjectCache().GetAutofillSuggestionAvailability(AXObjectID()) !=
WebAXAutofillSuggestionAvailability::kNoSuggestions) {
return ax::mojom::blink::HasPopup::kMenu;
}
return AXObject::HasPopup();
}
ax::mojom::blink::IsPopup AXNodeObject::IsPopup() const {
if (IsDetached() || !GetElement()) {
return ax::mojom::blink::IsPopup::kNone;
}
const auto* html_element = DynamicTo<HTMLElement>(GetElement());
if (!html_element) {
return ax::mojom::blink::IsPopup::kNone;
}
if (RoleValue() == ax::mojom::blink::Role::kMenuListPopup) {
return ax::mojom::blink::IsPopup::kAuto;
}
switch (html_element->PopoverType()) {
case PopoverValueType::kNone:
return ax::mojom::blink::IsPopup::kNone;
case PopoverValueType::kAuto:
return ax::mojom::blink::IsPopup::kAuto;
case PopoverValueType::kHint:
return ax::mojom::blink::IsPopup::kHint;
case PopoverValueType::kManual:
return ax::mojom::blink::IsPopup::kManual;
}
}
bool AXNodeObject::IsEditableRoot() const {
const Node* node = GetNode();
if (IsDetached() || !node)
return false;
#if DCHECK_IS_ON() // Required in order to get Lifecycle().ToString()
DCHECK(GetDocument());
DCHECK_GE(GetDocument()->Lifecycle().GetState(),
DocumentLifecycle::kStyleClean)
<< "Unclean document style at lifecycle state "
<< GetDocument()->Lifecycle().ToString();
#endif // DCHECK_IS_ON()
// Catches the case where the 'contenteditable' attribute is set on an atomic
// text field (which shouldn't have any effect).
if (IsAtomicTextField())
return false;
// The DOM inside native text fields is an implementation detail that should
// not be exposed to platform accessibility APIs.
if (EnclosingTextControl(node))
return false;
if (IsRootEditableElement(*node))
return true;
// Catches the case where a contenteditable is inside another contenteditable.
// This is especially important when the two nested contenteditables have
// different attributes, e.g. "true" vs. "plaintext-only".
if (HasContentEditableAttributeSet())
return true;
return false;
}
bool AXNodeObject::HasContentEditableAttributeSet() const {
if (IsDetached() || !GetNode())
return false;
const auto* html_element = DynamicTo<HTMLElement>(GetNode());
if (!html_element)
return false;
ContentEditableType normalized_value =
html_element->contentEditableNormalized();
return normalized_value == ContentEditableType::kContentEditable ||
normalized_value == ContentEditableType::kPlaintextOnly;
}
// Returns the nearest block-level LayoutBlockFlow ancestor
static LayoutBlockFlow* GetNearestBlockFlow(LayoutObject* object) {
LayoutObject* current = object;
while (current) {
if (auto* block_flow = DynamicTo<LayoutBlockFlow>(current)) {
return block_flow;
}
current = current->Parent();
}
NOTREACHED();
}
// Returns true if |r1| and |r2| are both non-null, both inline, and are
// contained within the same LayoutBlockFlow.
static bool IsInSameBlockFlow(LayoutObject* r1, LayoutObject* r2) {
if (!r1 || !r2)
return false;
if (!r1->IsInline() || !r2->IsInline())
return false;
LayoutBlockFlow* b1 = GetNearestBlockFlow(r1);
LayoutBlockFlow* b2 = GetNearestBlockFlow(r2);
return b1 && b2 && b1 == b2;
}
//
// Modify or take an action on an object.
//
bool AXNodeObject::OnNativeSetSelectedAction(bool selected) {
auto* option = DynamicTo<HTMLOptionElement>(GetNode());
if (!option) {
return false;
}
HTMLSelectElement* select_element = option->OwnerSelectElement();
if (!select_element) {
return false;
}
if (!CanSetSelectedAttribute()) {
return false;
}
AccessibilitySelectedState is_option_selected = IsSelected();
if (is_option_selected == kSelectedStateUndefined) {
return false;
}
bool is_selected = (is_option_selected == kSelectedStateTrue) ? true : false;
if ((is_selected && selected) || (!is_selected && !selected)) {
return false;
}
select_element->SelectOptionByAccessKey(To<HTMLOptionElement>(GetNode()));
return true;
}
bool AXNodeObject::OnNativeSetValueAction(const String& string) {
base::UmaHistogramEnumeration("Accessibility.SetValue.Role", RoleValue());
if (!GetNode() || !GetNode()->IsElementNode()) {
return false;
}
const LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->IsBoxModelObject()) {
return false;
}
auto* html_input_element = DynamicTo<HTMLInputElement>(*GetNode());
if (html_input_element && layout_object->IsTextField()) {
html_input_element->SetValue(
string, TextFieldEventBehavior::kDispatchInputAndChangeEvent);
return true;
}
if (auto* text_area_element = DynamicTo<HTMLTextAreaElement>(*GetNode())) {
DCHECK(layout_object->IsTextArea());
text_area_element->SetValue(
string, TextFieldEventBehavior::kDispatchInputAndChangeEvent);
return true;
}
if (HasContentEditableAttributeSet()) {
To<HTMLElement>(GetNode())->setInnerText(string);
return true;
}
return false;
}
//
// New AX name calculation.
//
String AXNodeObject::GetName(ax::mojom::blink::NameFrom& name_from,
AXObjectVector* name_objects,
AXNodeObject::NameSources* name_sources) const {
String name = AXObject::GetName(name_from, name_objects, name_sources);
// Fields inside a datetime control need to merge the field name with
// the name of the <input> element.
if (RoleValue() == ax::mojom::blink::Role::kSpinButton &&
DatetimeAncestor()) {
if (name_objects) {
name_objects->clear();
}
String input_name =
DatetimeAncestor()->GetName(name_from, name_objects, name_sources);
if (!input_name.empty())
return StrCat({name, " ", input_name});
}
// Handle ::scroll-button(*) pseudo-element names.
const Element* element = GetElement();
if (element && element->IsScrollButtonPseudoElement()) {
// Prioritize alt text if available.
std::optional<String> alt_text = GetCSSAltText(element);
if (alt_text && !alt_text->empty()) {
name_from = ax::mojom::blink::NameFrom::kCssAltText;
return *alt_text;
}
if (!name.empty()) {
// Scroll button has a non-empty name, so there is no need to use a
// fallback.
return name;
}
// If the alt text is not available, return a "Scroll [direction]" name,
const ComputedStyle* style =
GetLayoutObject() ? GetLayoutObject()->Style() : nullptr;
if (style) {
PhysicalDirection physical;
if (element->IsScrollButtonBlockStartPseudoElement()) {
physical = style->GetWritingDirection().BlockStart();
} else if (element->IsScrollButtonBlockEndPseudoElement()) {
physical = style->GetWritingDirection().BlockEnd();
} else if (element->IsScrollButtonInlineStartPseudoElement()) {
physical = style->GetWritingDirection().InlineStart();
} else if (element->IsScrollButtonInlineEndPseudoElement()) {
physical = style->GetWritingDirection().InlineEnd();
} else {
NOTREACHED()
<< "ScrollButtonPseudoElement must be one of known directions";
}
name_from = ax::mojom::blink::NameFrom::kCssAltText;
switch (physical) {
case PhysicalDirection::kRight:
return element->GetLocale().QueryString(IDS_AX_CAROUSEL_SCROLL_RIGHT);
case PhysicalDirection::kLeft:
return element->GetLocale().QueryString(IDS_AX_CAROUSEL_SCROLL_LEFT);
case PhysicalDirection::kDown:
return element->GetLocale().QueryString(IDS_AX_CAROUSEL_SCROLL_DOWN);
case PhysicalDirection::kUp:
return element->GetLocale().QueryString(IDS_AX_CAROUSEL_SCROLL_UP);
}
}
}
// Handle ::scroll-marker names. Pick the first one that matches:
// - Use CSS alt text if one is available.
// - Use CSS content (from LayoutText descendants) if specified and
// non-empty.
// - Use scroll target's accessibility name is it has one.
if (element && element->IsScrollMarkerPseudoElement()) {
std::optional<String> alt_text = GetCSSAltText(element);
if (alt_text && !alt_text->empty()) {
name_from = ax::mojom::blink::NameFrom::kCssAltText;
return *alt_text;
}
std::optional<String> content = GetCSSContentText(element);
if (content && !content->empty()) {
name_from = ax::mojom::blink::NameFrom::kContents;
return *content;
}
const AXObject* scroll_target =
AXObjectCache().Get(element->parentElement());
ax::mojom::blink::NameFrom name_source;
return scroll_target ? scroll_target->GetName(name_source, nullptr, nullptr)
: "";
}
return name;
}
String AXNodeObject::TextAlternative(
bool recursive,
const AXObject* aria_label_or_description_root,
AXObjectSet& visited,
ax::mojom::blink::NameFrom& name_from,
AXRelatedObjectVector* related_objects,
NameSources* name_sources) const {
// If nameSources is non-null, relatedObjects is used in filling it in, so it
// must be non-null as well.
DCHECK(!name_sources || related_objects);
bool found_text_alternative = false;
Node* node = GetNode();
name_from = ax::mojom::blink::NameFrom::kNone;
if (!node && !GetLayoutObject()) {
return String();
}
if (IsA<HTMLSlotElement>(node) && node->IsInUserAgentShadowRoot() &&
!recursive) {
// User agent slots do not have their own name, but their subtrees can
// contribute to ancestor names (where recursive == true).
return String();
}
if (GetLayoutObject()) {
std::optional<String> text_alternative = GetCSSAltText(GetElement());
if (text_alternative) {
name_from = ax::mojom::blink::NameFrom::kCssAltText;
if (name_sources) {
name_sources->push_back(NameSource(false));
name_sources->back().type = name_from;
name_sources->back().text = text_alternative.value();
}
return text_alternative.value();
}
if (GetLayoutObject()->IsBR()) {
text_alternative = String("\n");
found_text_alternative = true;
} else if (GetLayoutObject()->IsText() &&
(!recursive || !GetLayoutObject()->IsCounter())) {
auto* layout_text = To<LayoutText>(GetLayoutObject());
String visible_text = layout_text->PlainText(); // Actual rendered text.
// If no text boxes we assume this is unrendered end-of-line whitespace.
// TODO find robust way to deterministically detect end-of-line space.
if (visible_text.empty()) {
// No visible rendered text -- must be whitespace.
// Either it is useful whitespace for separating words or not.
if (layout_text->IsAllCollapsibleWhitespace()) {
if (IsIgnored()) {
return "";
}
// If no textboxes, this was whitespace at the line's end.
text_alternative = " ";
} else {
text_alternative = layout_text->TransformedText();
}
} else {
text_alternative = visible_text;
}
found_text_alternative = true;
} else if (!recursive) {
if (ListMarker* marker = ListMarker::Get(GetLayoutObject())) {
text_alternative = marker->TextAlternative(*GetLayoutObject());
found_text_alternative = true;
}
}
if (found_text_alternative) {
name_from = ax::mojom::blink::NameFrom::kContents;
if (name_sources) {
name_sources->push_back(NameSource(false));
name_sources->back().type = name_from;
name_sources->back().text = text_alternative.value();
}
// Ensure that text nodes count toward
// kMaxDescendantsForTextAlternativeComputation when calculating the name
// for their direct parent (see AXNodeObject::TextFromDescendants).
visited.insert(this);
return text_alternative.value();
}
}
// Step 2E from: http://www.w3.org/TR/accname-aam-1.1 -- value from control.
// This must occur before 2C, because 2C is not applied if 2E will be:
// 2C: "If traversal of the current node is due to recursion and the current
// node is an embedded control as defined in step 2E, ignore aria-label and
// skip to rule 2E".
// Note that 2E only applies the label is for "another widget", therefore, the
// value cannot be used to label the original control, even if aria-labelledby
// points to itself. The easiest way to check this is by testing whether this
// node has already been visited.
if (recursive && !visited.Contains(this)) {
String value_for_name = GetValueContributionToName(visited);
// TODO(accessibility): Consider using `empty` check instead of `IsNull`.
if (!value_for_name.IsNull()) {
name_from = ax::mojom::blink::NameFrom::kValue;
if (name_sources) {
name_sources->push_back(NameSource(false));
name_sources->back().type = ax::mojom::blink::NameFrom::kValue;
name_sources->back().text = value_for_name;
}
return value_for_name;
}
}
// Step 2C from: http://www.w3.org/TR/accname-aam-1.1 -- aria-label.
String text_alternative = AriaTextAlternative(
recursive, aria_label_or_description_root, visited, name_from,
related_objects, name_sources, &found_text_alternative);
if (found_text_alternative && !name_sources)
return MaybeAppendFileDescriptionToName(text_alternative);
// Step 2D from: http://www.w3.org/TR/accname-aam-1.1 -- native markup.
text_alternative =
NativeTextAlternative(visited, name_from, related_objects, name_sources,
&found_text_alternative);
// An explicitly empty native text alternative can still be overridden if a
// viable text alternative is found later in the search, so remember that it
// was explicitly empty here but don't terminate the search yet unless we
// already found something non-empty.
const bool has_explicitly_empty_native_text_alternative =
text_alternative.empty() &&
name_from == ax::mojom::blink::NameFrom::kAttributeExplicitlyEmpty;
if (!text_alternative.empty() && !name_sources) {
return MaybeAppendFileDescriptionToName(text_alternative);
}
// Step 2F / 2G from: http://www.w3.org/TR/accname-aam-1.1 -- from content.
if (ShouldIncludeContentInTextAlternative(
recursive, aria_label_or_description_root, visited)) {
name_from = ax::mojom::blink::NameFrom::kContents;
if (name_sources) {
name_sources->push_back(NameSource(found_text_alternative));
name_sources->back().type = name_from;
}
if (auto* text_node = DynamicTo<Text>(node)) {
text_alternative = text_node->data();
} else if (IsA<HTMLBRElement>(node)) {
text_alternative = String("\n");
} else {
text_alternative =
TextFromDescendants(visited, aria_label_or_description_root, false);
}
if (!text_alternative.empty()) {
if (name_sources) {
found_text_alternative = true;
name_sources->back().text = text_alternative;
} else {
return MaybeAppendFileDescriptionToName(text_alternative);
}
}
}
// Step 2I from: http://www.w3.org/TR/accname-aam-1.1
// Use the tooltip text for the name if there was no other accessible name.
// However, it does not make sense to do this if the object has a role
// that prohibits name as specified in
// https://w3c.github.io/aria/#namefromprohibited.
// Preventing the tooltip for being used in the name causes it to be used for
// the description instead.
// This complies with https://w3c.github.io/html-aam/#att-title, which says
// how to expose a title: "Either the accessible name, or the accessible
// description, or Not mapped". There's nothing in HTML-AAM that explicitly
// forbids this, and it seems reasonable for authors to use a tooltip on any
// visible element without causing an accessibility error or user problem.
// Note: if this is part of another label or description, it needs to be
// computed as a name, in order to contribute to that.
if (aria_label_or_description_root || !IsNameProhibited()) {
String resulting_text = TextAlternativeFromTooltip(
name_from, name_sources, &found_text_alternative, &text_alternative,
related_objects);
if (!resulting_text.empty()) {
if (name_sources) {
text_alternative = resulting_text;
} else {
return resulting_text;
}
}
}
String saved_text_alternative = GetSavedTextAlternativeFromNameSource(
found_text_alternative, name_from, related_objects, name_sources);
if (!saved_text_alternative.empty()) {
return saved_text_alternative;
}
if (has_explicitly_empty_native_text_alternative) {
// If the native text alternative is explicitly empty and we
// never found another text alternative, then set name_source
// to reflect the fact that there was an explicitly empty text
// alternative. This is important because an empty `alt` attribute on an
// <img> can be used to indicate that the image is presentational and should
// be ignored by ATs.
name_from = ax::mojom::blink::NameFrom::kAttributeExplicitlyEmpty;
}
return String();
}
static bool ShouldInsertSpaceBetweenObjectsIfNeeded(
AXObject* previous,
AXObject* next,
ax::mojom::blink::NameFrom last_used_name_from,
ax::mojom::blink::NameFrom name_from) {
LayoutObject* next_layout = next->GetLayoutObject();
LayoutObject* prev_layout = previous->GetLayoutObject();
// If we're going between two LayoutObjects that are in separate
// LayoutBoxes, add whitespace if it wasn't there already. Intuitively if
// you have <span>Hello</span><span>World</span>, those are part of the same
// LayoutBox so we should return "HelloWorld", but given
// <div>Hello</div><div>World</div> the strings are in separate boxes so we
// should return "Hello World".
// https://www.w3.org/TR/css-display-3/#the-display-properties
if (!IsInSameBlockFlow(next_layout, prev_layout)) {
return true;
}
// Even if we are in the same block flow, let's make sure to add whitespace
// if the layout objects define new formatting contexts for their children,
// as is the case with the inline-* family of display properties.
// So we want the following:
// <span style="display:inline-block;">Hello</span><span>World</span>
// <span style="display:inline-flex;">Hello</span><span>World</span>
// <span style="display:inline-grid;">Hello</span><span>World</span>
// <span style="display:inline-table;">Hello</span><span>World</span>
// to return "Hello World". See "inner display type" in the CSS Display 3.0
// spec: https://www.w3.org/TR/css-display-3/#the-display-properties
CHECK(next_layout);
CHECK(prev_layout);
if (next_layout->IsAtomicInlineLevel() ||
prev_layout->IsAtomicInlineLevel()) {
return true;
}
// Even if it is in the same inline block flow, if we are using a text
// alternative such as an ARIA label or HTML title, we should separate
// the strings. Doing so is consistent with what is stated in the AccName
// spec and with what is done in other user agents.
switch (last_used_name_from) {
case ax::mojom::blink::NameFrom::kNone:
case ax::mojom::blink::NameFrom::kAttributeExplicitlyEmpty:
case ax::mojom::blink::NameFrom::kContents:
case ax::mojom::blink::NameFrom::kProhibited:
case ax::mojom::blink::NameFrom::kProhibitedAndRedundant:
break;
case ax::mojom::blink::NameFrom::kAttribute:
case ax::mojom::blink::NameFrom::kCaption:
case ax::mojom::blink::NameFrom::kCssAltText:
case ax::mojom::blink::NameFrom::kInterestFor:
case ax::mojom::blink::NameFrom::kPlaceholder:
case ax::mojom::blink::NameFrom::kRelatedElement:
case ax::mojom::blink::NameFrom::kTitle:
case ax::mojom::blink::NameFrom::kValue:
case ax::mojom::blink::NameFrom::kPopoverTarget:
return true;
}
switch (name_from) {
case ax::mojom::blink::NameFrom::kNone:
case ax::mojom::blink::NameFrom::kAttributeExplicitlyEmpty:
case ax::mojom::blink::NameFrom::kContents:
case ax::mojom::blink::NameFrom::kProhibited:
case ax::mojom::blink::NameFrom::kProhibitedAndRedundant:
break;
case ax::mojom::blink::NameFrom::kAttribute:
case ax::mojom::blink::NameFrom::kCaption:
case ax::mojom::blink::NameFrom::kCssAltText:
case ax::mojom::blink::NameFrom::kInterestFor:
case ax::mojom::blink::NameFrom::kPlaceholder:
case ax::mojom::blink::NameFrom::kRelatedElement:
case ax::mojom::blink::NameFrom::kTitle:
case ax::mojom::blink::NameFrom::kValue:
case ax::mojom::blink::NameFrom::kPopoverTarget:
return true;
}
// According to the AccName spec, we need to separate controls from text nodes
// using a space.
if (previous->IsControl() || next->IsControl())
return true;
// When |previous| and |next| are in same inline formatting context, we
// may have block-in-inline between |previous| and |next|.
// For <div>abc<p aria-hidden=true>...</p>def</div>, we have following
// layout tree:
// LayoutBlockFlow {DIV}, children are inline
// LayoutText "abc" <= previous
// LayoutBlockFlow (anonymous) block-in-inline wrapper
// LayoutBlockFlow {P}
// ...
// LayoutText "def" <= next
// When block-in-inline disabled, layout tree is:
// LayoutBlockFlow {DIV}, children are block
// LayoutBlockFlow (anonymous)
// LayoutText "abc" <= previous
// LayoutBlockFlow (anonymous) block-in-inline wrapper
// LayoutBlockFlow {P}
// ...
// LayoutBlockFlow (anonymous)
// LayoutText "def" <= next
// See accessibility/name-calc-aria-hidden.html
for (auto* layout_object = previous->GetLayoutObject();
layout_object && layout_object != next_layout;
layout_object = layout_object->NextInPreOrder()) {
if (layout_object->IsBlockInInline())
return true;
}
return false;
}
String AXNodeObject::TextFromDescendants(
AXObjectSet& visited,
const AXObject* aria_label_or_description_root,
bool recursive) const {
if (!CanHaveChildren()) {
return recursive || !GetElement()
? String()
: GetElement()->GetInnerTextWithoutUpdate();
}
StringBuilder accumulated_text;
AXObject* previous = nullptr;
ax::mojom::blink::NameFrom last_used_name_from =
ax::mojom::blink::NameFrom::kNone;
AXObjectVector action_objects =
RelationVectorFromAria(html_names::kAriaActionsAttr);
CHECK(!NeedsToUpdateCachedValues());
const AXObjectVector& children = ChildrenIncludingIgnored();
#if AX_FAIL_FAST_BUILD()
base::AutoReset<bool> auto_reset(&is_computing_text_from_descendants_, true);
#endif
wtf_size_t num_children = children.size();
for (wtf_size_t index = 0; index < num_children; index++) {
DCHECK_EQ(children.size(), num_children);
if (index >= children.size()) {
// TODO(accessibility) Remove this condition once we solve all causes of
// the child list being altered during this loop.
break;
}
AXObject* child = children[index];
DCHECK(child);
DCHECK(!child->IsDetached()) << child;
constexpr size_t kMaxDescendantsForTextAlternativeComputation = 100;
if (visited.size() > kMaxDescendantsForTextAlternativeComputation)
break;
// Exclude nodes referenced by aria-actions.
if (action_objects.Contains(child)) {
continue;
}
if (child->IsHiddenForTextAlternativeCalculation(
aria_label_or_description_root)) {
continue;
}
ax::mojom::blink::NameFrom child_name_from =
ax::mojom::blink::NameFrom::kNone;
String result;
if (child->IsPresentational()) {
result = child->TextFromDescendants(visited,
aria_label_or_description_root, true);
} else {
result = RecursiveTextAlternative(*child, aria_label_or_description_root,
visited, child_name_from);
}
if (!result.empty() && previous && accumulated_text.length() &&
!IsHTMLSpace(accumulated_text[accumulated_text.length() - 1]) &&
!IsHTMLSpace(result[0])) {
if (ShouldInsertSpaceBetweenObjectsIfNeeded(
previous, child, last_used_name_from, child_name_from)) {
accumulated_text.Append(' ');
}
}
accumulated_text.Append(result);
// We keep track of all non-hidden children, even those whose content is
// not included, because all rendered children impact whether or not a
// space should be inserted between objects. Example: A label which has
// a single, nameless input surrounded by CSS-generated content should
// have a space separating the before and after content.
previous = child;
// We only keep track of the source of children whose content is included.
// Example: Three spans, the first with an aria-label, the second with no
// content, and the third whose name comes from content. There should be a
// space between the first and third because of the aria-label in the first.
if (!result.empty())
last_used_name_from = child_name_from;
}
return accumulated_text.ToString();
}
// static
bool AXNodeObject::IsNameFromLabelElement(HTMLElement* control) {
// This duplicates some logic from TextAlternative()/NativeTextAlternative(),
// but is necessary because IsNameFromLabelElement() needs to be called from
// ComputeIsIgnored(), which isn't allowed to call
// AXObjectCache().GetOrCreate() in random places in the tree.
if (!control)
return false;
// aria-label and aria-labelledby take precedence over <label>.
if (IsNameFromAriaAttribute(control))
return false;
// <label> will be used. It contains the control or points via <label for>.
// Based on https://www.w3.org/TR/html-aam-1.0
// 5.1/5.5 Text inputs, Other labelable Elements
auto* labels = control->labels();
return labels && labels->length();
}
// static
bool AXNodeObject::IsRedundantLabel(HTMLLabelElement* label) {
// Determine if label is redundant:
// - Labelling a checkbox or radio.
// - Text was already used to name the checkbox/radio.
// - No interesting content in the label (focusable or semantically useful)
// TODO(accessibility) Consider moving this logic to the browser side.
// TODO(accessibility) Consider this for more controls, such as textboxes.
// There isn't a clear history why this is only done for checkboxes, and not
// other controls such as textboxes. It may be because the checkbox/radio
// itself is small, so this makes a nicely sized combined click target. Most
// ATs do not already have features to combine labels and controls, e.g.
// removing redundant announcements caused by having text and named controls
// as separate objects.
HTMLInputElement* input = DynamicTo<HTMLInputElement>(label->Control());
if (!input)
return false;
if (!input->GetLayoutObject() ||
input->GetLayoutObject()->Style()->Visibility() !=
EVisibility::kVisible) {
return false;
}
if (!input->IsCheckable()) {
return false;
}
if (!IsNameFromLabelElement(input)) {
return false;
}
DCHECK_NE(input->labels()->length(), 0U);
// Look for any first child element that is not the input control itself.
// This could be important semantically.
Element* first_child = ElementTraversal::FirstChild(*label);
if (!first_child)
return true; // No element children.
if (first_child != input)
return false; // Has an element child that is not the input control.
// The first child was the input control.
// If there's another child, then it won't be the input control.
return ElementTraversal::NextSibling(*first_child) == nullptr;
}
void AXNodeObject::GetRelativeBounds(AXObject** out_container,
gfx::RectF& out_bounds_in_container,
gfx::Transform& out_container_transform,
bool* clips_children) const {
if (GetLayoutObject()) {
AXObject::GetRelativeBounds(out_container, out_bounds_in_container,
out_container_transform, clips_children);
return;
}
#if DCHECK_IS_ON()
DCHECK(!getting_bounds_) << "GetRelativeBounds reentrant: " << ToString();
base::AutoReset<bool> reentrancy_protector(&getting_bounds_, true);
#endif
*out_container = nullptr;
out_bounds_in_container = gfx::RectF();
out_container_transform.MakeIdentity();
if (RoleValue() == ax::mojom::blink::Role::kMenuListOption) {
// When a <select> is collapsed, the bounds of its options are the same as
// that of the containing <select>. Falling through will achieve this.
// TODO(accessibility): Support bounding boxes for <optgroup>. Could
// union the rect of the first and last option in it.
auto* select = To<HTMLOptionElement>(GetNode())->OwnerSelectElement();
if (auto* ax_select = AXObjectCache().Get(select)) {
if (ax_select->IsExpanded() == kExpandedExpanded) {
auto* options_bounds = AXObjectCache().GetOptionsBounds(*ax_select);
if (options_bounds) {
unsigned int index = static_cast<unsigned int>(
To<HTMLOptionElement>(GetNode())->index());
// Some <option> bounding boxes may not be sent, as a performance
// optimization. For example, only the first 1000 options may have
// bounding boxes. If no bounding box is available, then we serialize
// the option with everything except for that information.
if (index < options_bounds->size()) {
out_bounds_in_container = gfx::RectF(options_bounds->at(index));
}
return;
}
}
}
}
// First check if it has explicit bounds, for example if this element is tied
// to a canvas path. When explicit coordinates are provided, the ID of the
// explicit container element that the coordinates are relative to must be
// provided too.
if (auto canvas_bounds =
AXObjectCache().GetCanvasElementBounds(this->AXObjectID())) {
*out_container = AXObjectCache().ObjectFromAXID(canvas_bounds->second);
if (*out_container) {
out_bounds_in_container = gfx::RectF(canvas_bounds->first);
return;
}
}
Element* element = GetElement();
// If it's in a canvas but doesn't have an explicit rect, or has display:
// contents set, get the bounding rect of its children.
if ((GetNode()->ParentOrShadowHostElement() &&
GetNode()->ParentOrShadowHostElement()->IsCanvasOrInCanvasSubtree()) ||
(element && element->HasDisplayContentsStyle())) {
Vector<gfx::RectF> rects;
for (Node& child : NodeTraversal::ChildrenOf(*GetNode())) {
if (child.IsHTMLElement()) {
if (AXObject* obj = AXObjectCache().Get(&child)) {
AXObject* container;
gfx::RectF bounds;
obj->GetRelativeBounds(&container, bounds, out_container_transform,
clips_children);
if (container) {
*out_container = container;
rects.push_back(bounds);
}
}
}
}
if (*out_container) {
for (auto& rect : rects)
out_bounds_in_container.Union(rect);
return;
}
}
// If this object doesn't have an explicit element rect or computable from its
// children, for now, let's return the position of the ancestor that does have
// a position, and make it the width of that parent, and about the height of a
// line of text, so that it's clear the object is a child of the parent.
for (AXObject* position_provider = ParentObject(); position_provider;
position_provider = position_provider->ParentObject()) {
if (position_provider->GetLayoutObject()) {
position_provider->GetRelativeBounds(
out_container, out_bounds_in_container, out_container_transform,
clips_children);
if (*out_container) {
out_bounds_in_container.set_size(
gfx::SizeF(out_bounds_in_container.width(),
std::min(10.0f, out_bounds_in_container.height())));
}
break;
}
}
}
bool AXNodeObject::HasValidHTMLTableStructureAndLayout() const {
// Is it a visible <table> with a table-like role and layout?
if (!IsTableLikeRole() || !GetLayoutObject() ||
!GetLayoutObject()->IsTable() || !IsA<HTMLTableElement>(GetNode()))
return false;
// Check for any invalid children, as far as W3C table validity is concerned.
// * If no invalid children exist, this will be considered a valid table,
// and AddTableChildren() can be used to add the children in rendered order.
// * If any invalid children exist, this table will be considered invalid.
// In that case the children will still be added via AddNodeChildren(),
// so that no content is lost.
// See comments in AddTableChildren() for more information about valid tables.
auto* table = To<HTMLTableElement>(GetNode());
auto* thead = table->tHead();
auto* tfoot = table->tFoot();
for (Node* node = LayoutTreeBuilderTraversal::FirstChild(*GetElement()); node;
node = LayoutTreeBuilderTraversal::NextSibling(*node)) {
if (Element* child = DynamicTo<Element>(node)) {
if (child == thead || child == tfoot) {
// Only 1 thead and 1 tfoot are allowed.
continue;
}
if (IsA<HTMLTableSectionElement>(child) &&
child->HasTagName(html_names::kTbodyTag)) {
// Multiple <tbody>s are valid, but only 1 thead or tfoot.
continue;
}
if (!child->GetLayoutObject() &&
child->HasTagName(html_names::kColgroupTag)) {
continue;
}
if (IsA<HTMLTableCaptionElement>(child) && child == table->caption()) {
continue; // Only one caption is valid.
}
} else if (!node->GetLayoutObject()) {
continue;
}
return false;
}
return true;
}
void AXNodeObject::AddTableChildren() {
// Add the caption (if any) and table sections in the visible order.
//
// Implementation notes:
//
// * In a valid table, there is always at least one section child DOM node.
// For example, if the HTML of the web page includes <tr>s as direct
// children of a <table>, Blink will insert a <tbody> as a child of the
// table, and parent of the <tr> elements.
//
// * Rendered order can differ from DOM order:
// The valid DOM order of <table> children is specified here:
// https://html.spec.whatwg.org/multipage/tables.html#the-table-element,
// "... optionally a caption element, followed by zero or more
// colgroup elements, followed optionally by a thead element, followed by
// either zero or more tbody elements or one or more tr elements, followed
// optionally by a tfoot element"
// However, even if the DOM children occur in an incorrect order, Blink
// automatically renders them as if they were in the correct order.
// The following code ensures that the children are added to the AX tree in
// the same order as Blink renders them.
DCHECK(HasValidHTMLTableStructureAndLayout());
auto* html_table_element = To<HTMLTableElement>(GetNode());
AddNodeChild(html_table_element->caption());
AddNodeChild(html_table_element->tHead());
for (Node* node : *html_table_element->tBodies())
AddNodeChild(node);
AddNodeChild(html_table_element->tFoot());
}
int AXNodeObject::TextOffsetInFormattingContext(int offset) const {
DCHECK_GE(offset, 0);
if (IsDetached())
return 0;
// When a node has the first-letter CSS style applied to it, it is split into
// two parts (two branches) in the layout tree. The "first-letter part"
// contains its first letter and any surrounding Punctuation. The "remaining
// part" contains the rest of the text.
//
// We need to ensure that we retrieve the correct layout object: either the
// one for the "first-letter part" or the one for the "remaining part",
// depending of the value of |offset|.
const LayoutObject* layout_obj =
GetNode() ? AssociatedLayoutObjectOf(*GetNode(), offset)
: GetLayoutObject();
if (!layout_obj)
return AXObject::TextOffsetInFormattingContext(offset);
// We support calculating the text offset from the start of the formatting
// contexts of the following layout objects, provided that they are at
// inline-level, (display=inline) or "display=inline-block":
//
// (Note that in the following examples, the paragraph is the formatting
// context.
//
// Layout replaced, e.g. <p><img></p>.
// Layout inline with a layout text child, e.g. <p><a href="#">link</a></p>.
// Layout block flow, e.g. <p><b style="display: inline-block;"></b></p>.
// Layout text, e.g. <p>Hello</p>.
// Layout br (subclass of layout text), e.g. <p><br></p>.
if (layout_obj->IsLayoutInline()) {
// The OffsetMapping class doesn't map layout inline objects to their text
// mappings because such an operation could be ambiguous. An inline object
// may have another inline object inside it. For example,
// <span><span>Inner</span outer</span>. We need to recursively retrieve the
// first layout text or layout replaced child so that any potential
// ambiguity would be removed.
const AXObject* first_child = FirstChildIncludingIgnored();
return first_child ? first_child->TextOffsetInFormattingContext(offset)
: offset;
}
// TODO(crbug.com/567964): LayoutObject::IsAtomicInlineLevel() also includes
// block-level replaced elements. We need to explicitly exclude them via
// LayoutObject::IsInline().
const bool is_atomic_inline_level =
layout_obj->IsInline() && layout_obj->IsAtomicInlineLevel();
if (!is_atomic_inline_level && !layout_obj->IsText()) {
// Not in a formatting context in which text offsets are meaningful.
return AXObject::TextOffsetInFormattingContext(offset);
}
// TODO(crbug.com/1149171): NGInlineOffsetMappingBuilder does not properly
// compute offset mappings for empty LayoutText objects. Other text objects
// (such as some list markers) are not affected.
if (const LayoutText* layout_text = DynamicTo<LayoutText>(layout_obj)) {
if (layout_text->HasEmptyText()) {
return AXObject::TextOffsetInFormattingContext(offset);
}
}
LayoutBlockFlow* formatting_context =
OffsetMapping::GetInlineFormattingContextOf(*layout_obj);
if (!formatting_context || formatting_context == layout_obj)
return AXObject::TextOffsetInFormattingContext(offset);
// If "formatting_context" is not a Layout NG object, the offset mappings will
// be computed on demand and cached.
const OffsetMapping* inline_offset_mapping =
InlineNode::GetOffsetMapping(formatting_context);
if (!inline_offset_mapping)
return AXObject::TextOffsetInFormattingContext(offset);
const base::span<const OffsetMappingUnit> mapping_units =
inline_offset_mapping->GetMappingUnitsForLayoutObject(*layout_obj);
if (mapping_units.empty())
return AXObject::TextOffsetInFormattingContext(offset);
return static_cast<int>(mapping_units.front().TextContentStart()) + offset;
}
//
// Inline text boxes.
//
void AXNodeObject::LoadInlineTextBoxes() {
#if DCHECK_IS_ON()
DCHECK(GetDocument()->Lifecycle().GetState() >=
DocumentLifecycle::kLayoutClean)
<< "Unclean document at lifecycle "
<< GetDocument()->Lifecycle().ToString();
#endif
std::queue<AXID> work_queue;
work_queue.push(AXObjectID());
while (!work_queue.empty()) {
AXObject* work_obj = AXObjectCache().ObjectFromAXID(work_queue.front());
work_queue.pop();
if (!work_obj || !work_obj->IsIncludedInTree()) {
continue;
}
if (CanHaveInlineTextBoxChildren(work_obj) && HasLayoutText(work_obj)) {
if (work_obj->CachedChildrenIncludingIgnored().empty()) {
// We only need to add inline textbox children if they aren't present.
// Although some platforms (e.g. Android), load inline text boxes
// on subtrees that may later be stale, once they are stale, the old
// inline text boxes are cleared because SetNeedsToUpdateChildren()
// calls ClearChildren().
work_obj->LoadInlineTextBoxesHelper();
}
} else {
for (const auto& child : work_obj->ChildrenIncludingIgnored())
work_queue.push(child->AXObjectID());
}
}
// If the work was deferred via ChildrenChanged(), update accessibility
// to force that work to be performed now.
if (!AXObjectCache().lifecycle().StateAllowsImmediateTreeUpdates()) {
AXObjectCache().UpdateAXForAllDocuments();
}
}
void AXNodeObject::LoadInlineTextBoxesHelper() {
// The inline textbox children start empty.
DCHECK(CachedChildrenIncludingIgnored().empty());
#if defined(REDUCE_AX_INLINE_TEXTBOXES)
// Keep inline text box children up-to-date for this object in the future.
// This is only necessary on Android, which tries to skip inline text boxes
// for most objects.
SetAlwaysLoadInlineTextBoxes(true);
#endif
if (AXObjectCache().lifecycle().StateAllowsImmediateTreeUpdates()) {
// Can only add new objects while processing deferred events.
if (::features::IsAccessibilityBlockFlowIteratorEnabled()) {
AddInlineTextBoxChildrenWithBlockFlowIterator();
} else {
AddInlineTextBoxChildren();
}
// Avoid adding these children twice.
SetNeedsToUpdateChildren(false);
// If inline text box children were added, mark the node dirty so that the
// results are serialized.
if (!CachedChildrenIncludingIgnored().empty()) {
AXObjectCache().AddDirtyObjectToSerializationQueue(
this, ax::mojom::blink::EventFrom::kNone,
ax::mojom::blink::Action::kNone, {});
}
} else {
// Wait until processing deferred events.
AXObjectCache().ChildrenChanged(this);
}
}
void AXNodeObject::AddInlineTextBoxChildrenWithBlockFlowIterator() {
CHECK(GetDocument());
CHECK(ShouldLoadInlineTextBoxes());
CHECK(GetLayoutObject());
GetLayoutObject()->CheckIsNotDestroyed();
CHECK(GetLayoutObject()->IsText()) << GetLayoutObject() << " " << this;
CHECK(!GetLayoutObject()->NeedsLayout());
CHECK(AXObjectCache().lifecycle().StateAllowsImmediateTreeUpdates())
<< AXObjectCache();
AXBlockFlowIterator it(this);
while (it.Next()) {
AXObject* box =
AXObjectCache().GetOrCreate(it.CurrentFragmentIndex(), this);
if (!box) {
return;
}
children_.push_back(box);
}
}
void AXNodeObject::AddInlineTextBoxChildren() {
CHECK(GetDocument());
CHECK(ShouldLoadInlineTextBoxes());
CHECK(GetLayoutObject());
GetLayoutObject()->CheckIsNotDestroyed();
CHECK(GetLayoutObject()->IsText()) << GetLayoutObject() << " " << this;
CHECK(!GetLayoutObject()->NeedsLayout());
CHECK(AXObjectCache().GetAXMode().has_mode(ui::AXMode::kInlineTextBoxes));
CHECK(!AXObjectCache().GetAXMode().HasFilterFlags(
ui::AXMode::kFormsAndLabelsOnly))
<< "Form controls mode should not have inline text boxes turned on.";
CHECK(AXObjectCache().lifecycle().StateAllowsImmediateTreeUpdates())
<< AXObjectCache();
auto* layout_text = To<LayoutText>(GetLayoutObject());
for (auto* box = layout_text->FirstAbstractInlineTextBox(); box;
box = box->NextInlineTextBox()) {
AXObject* ax_box = AXObjectCache().GetOrCreate(box, this);
if (!ax_box) {
continue;
}
children_.push_back(ax_box);
}
}
void AXNodeObject::AddValidationMessageChild() {
DCHECK(IsWebArea()) << "Validation message must be child of root";
// First child requirement enables easy checking to see if a children changed
// event is needed in AXObjectCacheImpl::ValidationMessageObjectIfInvalid().
DCHECK_EQ(children_.size(), 0U)
<< "Validation message must be the first child";
AddChildAndCheckIncluded(AXObjectCache().ValidationMessageObjectIfInvalid());
}
void AXNodeObject::AddImageMapChildren() {
HTMLMapElement* map = GetMapForImage(GetNode());
if (!map)
return;
HTMLImageElement* curr_image_element = DynamicTo<HTMLImageElement>(GetNode());
DCHECK(curr_image_element);
DCHECK(curr_image_element->IsLink());
DCHECK(
!curr_image_element->FastGetAttribute(html_names::kUsemapAttr).empty());
// Even though several images can point to the same map via usemap, only
// use one reported via HTMLImageMapElement::ImageElement(), which is always
// the first image in the DOM that matches the #usemap, even if there are
// changes to the DOM. Only allow map children for the primary image.
// This avoids two problems:
// 1. Focusing the same area but in a different image scrolls the page to
// the first image that uses that map. Safari does the same thing, and
// Firefox does something similar (but seems to prefer the last image).
// 2. When an object has multiple parents, serialization errors occur.
// While allowed in the spec, using multiple images with the same map is not
// handled well in browsers (problem #1), and serializer support for multiple
// parents of the same area children is messy.
// Get the primary image, which is the first image using this map.
HTMLImageElement* primary_image_element = map->ImageElement();
// Is this the primary image for this map?
if (primary_image_element != curr_image_element) {
return;
}
// Yes, this is the primary image.
// Add the children to |this|.
Node* child = LayoutTreeBuilderTraversal::FirstChild(*map);
while (child) {
AddChildAndCheckIncluded(AXObjectCache().GetOrCreate(child, this));
child = LayoutTreeBuilderTraversal::NextSibling(*child);
}
}
void AXNodeObject::AddPopupChildren() {
if (AXObjectCache().IsForSnapshot()) {
// The snapshotter is unaware of the popup document.
return;
}
auto* html_select_element = DynamicTo<HTMLSelectElement>(GetNode());
if (html_select_element) {
if (html_select_element->UsesMenuList()) {
AddChildAndCheckIncluded(html_select_element->PopupRootAXObject());
}
return;
}
auto* html_input_element = DynamicTo<HTMLInputElement>(GetNode());
if (html_input_element) {
AddChildAndCheckIncluded(html_input_element->PopupRootAXObject());
}
}
void AXNodeObject::AddPseudoElementChildrenFromLayoutTree() {
// Children are added this way only for pseudo-element subtrees.
// See AXObject::ShouldUseLayoutObjectTraversalForChildren().
if (!IsVisible() || !GetLayoutObject()) {
DCHECK(GetNode());
DCHECK(GetNode()->IsPseudoElement());
return; // Can't add children for hidden or display-locked pseudo-elements.
}
LayoutObject* child = GetLayoutObject()->SlowFirstChild();
while (child) {
// All added pseudo-element descendants are included in the tree.
if (AXObject* ax_child = AXObjectCache().GetOrCreate(child, this)) {
DCHECK(AXObjectCacheImpl::IsRelevantPseudoElementDescendant(*child));
AddChildAndCheckIncluded(ax_child);
}
child = child->NextSibling();
}
}
void AXNodeObject::AddNodeChildren() {
if (!node_)
return;
// Ignore DOM children of frame/iframe: they do not act as fallbacks and
// are never part of layout.
if (IsA<HTMLFrameElementBase>(GetNode()))
return;
// If node has reading flow children, then we should reading-flow order.
// Note that this is only used for the case where the element is a
// reading-flow container, and not for the case where the element is a
// reading-flow item.
HeapVector<Member<Node>> reading_flow_children;
if (Element* element = GetElement()) {
reading_flow_children = element->ReadingFlowChildren();
}
if (!reading_flow_children.empty()) {
HeapHashSet<Member<Node>> ax_children_added;
// Add reading flow siblings in order.
for (Node* reading_flow_item : reading_flow_children) {
if (IsAddedOnlyViaSpecialTraversal(reading_flow_item)) {
continue;
}
if (ax_children_added.insert(reading_flow_item).is_new_entry) {
AddNodeChild(reading_flow_item);
}
}
#if DCHECK_IS_ON()
// At this point, the number of AXObject children added should equal the
// number of LayoutTreeBuilderTraversal children.
size_t num_layout_tree_children = 0;
for (Node* child = LayoutTreeBuilderTraversal::FirstChild(*node_); child;
child = LayoutTreeBuilderTraversal::NextSibling(*child)) {
if (IsAddedOnlyViaSpecialTraversal(child)) {
continue;
}
DCHECK(ax_children_added.Contains(child));
++num_layout_tree_children;
}
DCHECK_EQ(ax_children_added.size(), num_layout_tree_children);
#endif
} else {
for (Node* child = LayoutTreeBuilderTraversal::FirstChild(*node_); child;
child = LayoutTreeBuilderTraversal::NextSibling(*child)) {
if (IsAddedOnlyViaSpecialTraversal(child)) {
continue;
}
AddNodeChild(child);
}
}
}
void AXNodeObject::AddOwnedChildren() {
AXObjectVector owned_children;
AXObjectCache().ValidatedAriaOwnedChildren(this, owned_children);
DCHECK(owned_children.size() == 0 || AXRelationCache::IsValidOwner(this))
<< "This object is not allowed to use aria-owns, but it is.\n"
<< this;
// Always include owned children.
for (const auto& owned_child : owned_children) {
DCHECK(owned_child->GetNode());
DCHECK(AXRelationCache::IsValidOwnedChild(*owned_child->GetNode()))
<< "This object is not allowed to be owned, but it is.\n"
<< owned_child;
AddChildAndCheckIncluded(owned_child, true);
}
}
void AXNodeObject::AddChildrenImpl() {
#define CHECK_ATTACHED() \
if (IsDetached()) { \
NOTREACHED() << "Detached adding children: " << this; \
}
CHECK(NeedsToUpdateChildren());
CHECK(CanHaveChildren());
if (ShouldLoadInlineTextBoxes() && HasLayoutText(this)) {
if (::features::IsAccessibilityBlockFlowIteratorEnabled()) {
AddInlineTextBoxChildrenWithBlockFlowIterator();
} else {
AddInlineTextBoxChildren();
}
CHECK_ATTACHED();
return;
}
if (IsA<HTMLImageElement>(GetNode())) {
AddImageMapChildren();
CHECK_ATTACHED();
return;
}
// If validation message exists, always make it the first child of the root,
// to enable easy checking of whether it's a known child of the root.
if (IsWebArea())
AddValidationMessageChild();
CHECK_ATTACHED();
if (HasValidHTMLTableStructureAndLayout()) {
AddTableChildren();
} else if (GetNode() && GetNode()->IsScrollMarkerGroupPseudoElement()) {
AddScrollMarkerGroupChildren();
} else if (ShouldUseLayoutObjectTraversalForChildren()) {
AddPseudoElementChildrenFromLayoutTree();
} else {
AddNodeChildren();
}
CHECK_ATTACHED();
AddPopupChildren();
CHECK_ATTACHED();
AddOwnedChildren();
CHECK_ATTACHED();
}
void AXNodeObject::AddScrollMarkerGroupChildren() {
DCHECK(GetNode() && GetNode()->IsScrollMarkerGroupPseudoElement());
if (!IsVisible() || !GetLayoutObject()) {
DCHECK(GetNode());
DCHECK(GetNode()->IsPseudoElement());
// Can't add children for hidden or display-locked pseudo-elements.
return;
}
// In the DOM tree, a carousel looks like the following
// Scroller
// Item
// ::scroll-marker
// ::scroll-marker-group
//
// The following is the corresponding layout tree:
// Scroller
// Item
// ::scroll-marker-group
// Anonymous layout object
// ::scroll-marker
//
// The desired AX tree is the following:
// Scroller
// Item
// ::scroll-marker-group
// ::scroll-marker
//
// So far, we added items as they appeared in the Layout tree, with the
// exception that we pruned ::scroll-markers any time we saw them (see
// IsAddedOnlyViaSpecialTraversal). Now, we've reached ::scroll-marker-group.
// From here, we use the layout object walk skipping any anonymous layout
// objects. In fact, we only add ::scroll-markers. When this function is done,
// we should have our desired AX tree.
//
LayoutObject* child = GetLayoutObject()->SlowFirstChild();
while (child) {
DCHECK(
child->IsAnonymous() ||
(child->GetNode() && child->GetNode()->IsScrollMarkerPseudoElement()));
if (child->GetNode() && child->GetNode()->IsScrollMarkerPseudoElement()) {
AddNodeChild(child->GetNode());
}
// Iterate the whole subtree staying within the ::scroll-marker-group.
child = child->NextInPreOrder(GetLayoutObject());
}
}
void AXNodeObject::AddChildren() {
#if DCHECK_IS_ON()
DCHECK(!IsDetached());
// If the need to add more children in addition to existing children arises,
// childrenChanged should have been called, which leads to children_dirty_
// being true, then UpdateChildrenIfNecessary() clears the children before
// calling AddChildren().
DCHECK(children_.empty()) << "\nParent still has " << children_.size()
<< " children before adding:" << "\nParent is "
<< this << "\nFirst child is " << children_[0];
#endif
#if AX_FAIL_FAST_BUILD()
SANITIZER_CHECK(!is_computing_text_from_descendants_)
<< "Should not attempt to simultaneously compute text from descendants "
"and add children on: "
<< this;
SANITIZER_CHECK(!is_adding_children_) << " Reentering method on " << this;
base::AutoReset<bool> reentrancy_protector(&is_adding_children_, true);
#endif
AddChildrenImpl();
SetNeedsToUpdateChildren(false);
#if DCHECK_IS_ON()
// All added children must be attached.
for (const auto& child : children_) {
DCHECK(!child->IsDetached()) << "A brand new child was detached.\n"
<< child << "\n ... of parent " << this;
}
#endif
}
// Add non-owned children that are backed with a DOM node.
void AXNodeObject::AddNodeChild(Node* node) {
if (!node)
return;
if (Element* element = DynamicTo<Element>(node);
element && element->HasScrollButtonOrMarkerGroupPseudos()) {
VectorOf<Node> children = UnpackScrollerWithSiblingControls(element);
for (auto child : children) {
AddNodeChildImpl(child.Get());
}
} else {
AddNodeChildImpl(node);
}
}
void AXNodeObject::AddNodeChildImpl(Node* node) {
CHECK(node);
AXObject* ax_child = AXObjectCache().Get(node);
CHECK(!ax_child || !ax_child->IsDetached());
// Should not have another parent unless owned.
if (AXObjectCache().IsAriaOwned(ax_child))
return; // Do not add owned children to their natural parent.
AXObject* ax_cached_parent =
ax_child ? ax_child->ParentObjectIfPresent() : nullptr;
if (!ax_child) {
ax_child =
AXObjectCache().CreateAndInit(node, node->GetLayoutObject(), this);
if (!ax_child) {
return;
}
CHECK(!ax_child->IsDetached());
}
AddChild(ax_child);
// If we are adding an included child, check to see that it didn't have a
// different previous parent, because that indicates something strange is
// happening -- we shouldn't be stealing AXObjects from other parents here.
bool did_add_child_as_included =
children_.size() && children_[children_.size() - 1] == ax_child;
if (did_add_child_as_included && ax_cached_parent) {
CHECK(ax_child->IsIncludedInTree());
DUMP_WILL_BE_CHECK(ax_cached_parent->AXObjectID() == AXObjectID())
<< "Newly added child shouldn't have a different preexisting parent:"
<< "\nChild = " << ax_child << "\nNew parent = " << this
<< "\nPreexisting parent = " << ax_cached_parent;
}
}
#if DCHECK_IS_ON()
void AXNodeObject::CheckValidChild(AXObject* child) {
DCHECK(!child->IsDetached()) << "Cannot add a detached child.\n" << child;
Node* child_node = child->GetNode();
// <area> children should only be added via AddImageMapChildren(), as the
// descendants of an <image usemap> -- never alone or as children of a <map>.
if (IsA<HTMLAreaElement>(child_node)) {
AXObject* ancestor = this;
while (ancestor && !IsA<HTMLImageElement>(ancestor->GetNode()))
ancestor = ancestor->ParentObject();
DCHECK(ancestor && IsA<HTMLImageElement>(ancestor->GetNode()))
<< "Area elements can only be added by image parents: " << child
<< " had a parent of " << this;
}
DCHECK(!IsA<HTMLFrameElementBase>(GetNode()) ||
IsA<Document>(child->GetNode()))
<< "Cannot have a non-document child of a frame or iframe."
<< "\nChild: " << child << "\nParent: " << child->ParentObject();
}
#endif
void AXNodeObject::AddChild(AXObject* child, bool is_from_aria_owns) {
if (!child)
return;
#if DCHECK_IS_ON()
CheckValidChild(child);
#endif
unsigned int index = children_.size();
InsertChild(child, index, is_from_aria_owns);
}
void AXNodeObject::AddChildAndCheckIncluded(AXObject* child,
bool is_from_aria_owns) {
if (!child)
return;
DCHECK(child->CachedIsIncludedInTree());
AddChild(child, is_from_aria_owns);
}
void AXNodeObject::InsertChild(AXObject* child,
unsigned index,
bool is_from_aria_owns) {
if (!child)
return;
DCHECK(CanHaveChildren());
DCHECK(!child->IsDetached()) << "Cannot add a detached child: " << child;
// Enforce expected aria-owns status:
// - Don't add a non-aria-owned child when called from AddOwnedChildren().
// - Don't add an aria-owned child to its natural parent, because it will
// already be the child of the element with aria-owns.
DCHECK_EQ(AXObjectCache().IsAriaOwned(child), is_from_aria_owns);
// Set the parent:
// - For a new object it will have already been set.
// - For a reused, older object, it may need to be changed to a new parent.
child->SetParent(this);
if (ChildrenNeedToUpdateCachedValues()) {
child->InvalidateCachedValues(TreeUpdateReason::kChildInserted);
}
// Update cached values preemptively, but don't allow children changed to be
// called on the parent if the ignored state changes, as we are already
// recomputing children and don't want to recurse.
child->UpdateCachedAttributeValuesIfNeeded(
/*notify_parent_of_ignored_changes*/ false);
if (!child->IsIncludedInTree()) {
DCHECK(!is_from_aria_owns) << "Owned elements must be in tree: " << child
<< "\nRecompute included in tree: "
<< child->ComputeIsIgnoredButIncludedInTree();
// Get the ignored child's children and add to children of ancestor
// included in tree. This will recurse if necessary, skipping levels of
// unignored descendants as it goes.
const auto& children = child->ChildrenIncludingIgnored();
wtf_size_t length = children.size();
int new_index = index;
for (wtf_size_t i = 0; i < length; ++i) {
if (children[i]->IsDetached()) {
// TODO(crbug.com/452392024): Investigate why this is reached, fix it,
// and move to a NOTREACHED.
DUMP_WILL_BE_NOTREACHED()
<< "Cannot add a detached child: " << "\n* Child: " << children[i]
<< "\n* Parent: " << child << "\n* Grandparent: " << this;
continue;
}
// If the child was owned, it will be added elsewhere as a direct
// child of the object owning it.
if (!AXObjectCache().IsAriaOwned(children[i]))
children_.insert(new_index++, children[i]);
}
} else {
children_.insert(index, child);
}
}
bool AXNodeObject::CanHaveChildren() const {
DCHECK(!IsDetached());
// A child tree has been stitched onto this node, hiding its usual subtree.
if (AXObjectCache().GetAXObjectChildAXTreeID(AXObjectID())) {
return false;
}
// Notes:
// * Native text fields expose any children they might have, complying
// with browser-side expectations that editable controls have children
// containing the actual text content.
// * ARIA roles with childrenPresentational:true in the ARIA spec expose
// their contents to the browser side, allowing platforms to decide whether
// to make them a leaf, ensuring that focusable content cannot be hidden,
// and improving stability in Blink.
bool result = !GetElement() || AXObject::CanHaveChildren(*GetElement());
switch (native_role_) {
case ax::mojom::blink::Role::kListBoxOption:
// Option elements are allowed to have children according to the content
// model in the HTML spec.
break;
case ax::mojom::blink::Role::kCheckBox:
case ax::mojom::blink::Role::kMenuItemCheckBox:
case ax::mojom::blink::Role::kMenuItemRadio:
case ax::mojom::blink::Role::kProgressIndicator:
case ax::mojom::blink::Role::kRadioButton:
case ax::mojom::blink::Role::kScrollBar:
case ax::mojom::blink::Role::kSlider:
case ax::mojom::blink::Role::kSplitter:
case ax::mojom::blink::Role::kSwitch:
case ax::mojom::blink::Role::kTab:
DCHECK(!result) << "Expected to disallow children for:" << "\n* Node: "
<< GetNode() << "\n* Layout Object: " << GetLayoutObject()
<< "\n* Native role: " << native_role_
<< "\n* Aria role: " << RawAriaRole();
break;
case ax::mojom::blink::Role::kComboBoxSelect:
case ax::mojom::blink::Role::kMenuItem:
case ax::mojom::blink::Role::kPopUpButton:
case ax::mojom::blink::Role::kStaticText:
// Note: these can have AXInlineTextBox children, but when adding them, we
// also check AXObjectCache().InlineTextBoxAccessibilityEnabled().
DCHECK(result) << "Expected to allow children for " << GetElement()
<< " on role " << native_role_;
break;
default:
break;
}
return result;
}
//
// Properties of the object's owning document or page.
//
double AXNodeObject::EstimatedLoadingProgress() const {
if (!GetDocument())
return 0;
if (IsLoaded())
return 1.0;
if (LocalFrame* frame = GetDocument()->GetFrame())
return frame->Loader().Progress().EstimatedProgress();
return 0;
}
//
// DOM and Render tree access.
//
Element* AXNodeObject::ActionElement() const {
const AXObject* current = this;
if (blink::IsA<blink::Document>(current->GetNode()))
return nullptr; // Do not expose action element for document.
// In general, we look an action element up only for AXObjects that have a
// backing Element. We make an exception for text nodes and pseudo-elements
// because we also want these to expose a default action when any of their
// ancestors is clickable. We have found Windows ATs relying on this behavior
// (see https://crbug.com/1382034).
DCHECK(current->GetElement() || current->IsTextObject() ||
current->ShouldUseLayoutObjectTraversalForChildren());
while (current) {
// Handles clicks or is a textfield and is not a disabled form control.
if (current->IsClickable()) {
Element* click_element = current->GetElement();
DCHECK(click_element) << "Only elements are clickable";
// Only return if the click element is a DOM ancestor as well, because
// the click handler won't propagate down via aria-owns.
if (!GetNode() || click_element->contains(GetNode()))
return click_element;
return nullptr;
}
current = current->ParentObject();
}
return nullptr;
}
Element* AXNodeObject::AnchorElement() const {
// Search up the DOM tree for an anchor. This can be anything that has the
// linked state, such as an HTMLAnchorElement or role=link/doc-backlink.
const AXObject* current = this;
while (current) {
if (current->IsLink()) {
if (!current->GetElement()) {
// TODO(crbug.com/1524124): Investigate and fix why this gets hit.
DUMP_WILL_BE_NOTREACHED()
<< "An AXObject* that is a link should always have an element.\n"
<< this << "\n"
<< current;
}
return current->GetElement();
}
current = current->ParentObject();
}
return nullptr;
}
Document* AXNodeObject::GetDocument() const {
if (GetNode()) {
return &GetNode()->GetDocument();
}
if (GetLayoutObject()) {
return &GetLayoutObject()->GetDocument();
}
return nullptr;
}
LayoutObject* AXNodeObject::GetLayoutObject() const {
return layout_object_;
}
bool AXNodeObject::OnNativeBlurAction() {
Document* document = GetDocument();
Node* node = GetNode();
if (!document || !node) {
return false;
}
// An AXObject's node will always be of type `Element`, `Document` or
// `Text`. If the object we're currently on is associated with the currently
// focused element or the document object, we want to clear the focus.
// Otherwise, no modification is needed.
Element* element = GetElement();
if (element) {
element->blur();
return true;
}
if (IsA<Document>(GetNode())) {
document->ClearFocusedElement();
return true;
}
return false;
}
bool AXNodeObject::OnNativeFocusAction() {
Document* document = GetDocument();
Node* node = GetNode();
if (!document || !node)
return false;
if (!CanSetFocusAttribute())
return false;
if (IsWebArea()) {
// If another Frame has focused content (e.g. nested iframe), then we
// need to clear focus for the other Document Frame.
// Here we set the focused element via the FocusController so that the
// other Frame loses focus, and the target Document Element gains focus.
// This fixes a scenario with Narrator Item Navigation when the user
// navigates from the outer UI to the document when the last focused
// element was within a nested iframe before leaving the document frame.
if (Page* page = document->GetPage()) {
page->GetFocusController().SetFocusedElement(document->documentElement(),
document->GetFrame());
} else {
document->ClearFocusedElement();
}
return true;
}
Element* element = GetElement();
if (!element) {
document->ClearFocusedElement();
return true;
}
#if BUILDFLAG(IS_ANDROID)
// If this node is already the currently focused node, then calling
// focus() won't do anything. That is a problem when focus is removed
// from the webpage to chrome, and then returns. In these cases, we need
// to do what keyboard and mouse focus do, which is reset focus first.
if (document->FocusedElement() == element) {
document->ClearFocusedElement();
// Calling ClearFocusedElement could result in changes to the document,
// like this AXObject becoming detached.
if (IsDetached()) {
return false;
}
}
#endif
element->Focus(FocusParams(FocusTrigger::kUserGesture));
// Calling NotifyUserActivation here allows the browser to activate features
// that need user activation, such as showing an autofill suggestion.
LocalFrame::NotifyUserActivation(
document->GetFrame(),
mojom::blink::UserActivationNotificationType::kInteraction);
return true;
}
bool AXNodeObject::OnNativeIncrementAction() {
LocalFrame* frame = GetDocument() ? GetDocument()->GetFrame() : nullptr;
LocalFrame::NotifyUserActivation(
frame, mojom::blink::UserActivationNotificationType::kInteraction);
AlterSliderOrSpinButtonValue(true);
return true;
}
bool AXNodeObject::OnNativeDecrementAction() {
LocalFrame* frame = GetDocument() ? GetDocument()->GetFrame() : nullptr;
LocalFrame::NotifyUserActivation(
frame, mojom::blink::UserActivationNotificationType::kInteraction);
AlterSliderOrSpinButtonValue(false);
return true;
}
bool AXNodeObject::OnNativeSetSequentialFocusNavigationStartingPointAction() {
if (!GetNode())
return false;
Document* document = GetDocument();
document->ClearFocusedElement();
document->SetSequentialFocusNavigationStartingPoint(GetNode());
return true;
}
void AXNodeObject::SelectedOptions(AXObjectVector& options) const {
if (auto* select = DynamicTo<HTMLSelectElement>(GetNode())) {
for (auto* const option : *select->selectedOptions()) {
AXObject* ax_option = AXObjectCache().Get(option);
if (ax_option)
options.push_back(ax_option);
}
return;
}
const AXObjectVector& children = ChildrenIncludingIgnored();
if (RoleValue() == ax::mojom::blink::Role::kComboBoxGrouping ||
RoleValue() == ax::mojom::blink::Role::kComboBoxMenuButton) {
for (const auto& obj : children) {
if (obj->RoleValue() == ax::mojom::blink::Role::kListBox) {
obj->SelectedOptions(options);
return;
}
}
}
for (const auto& obj : children) {
if (obj->IsSelected() == kSelectedStateTrue)
options.push_back(obj);
}
}
//
// Notifications that this object may have changed.
//
void AXNodeObject::HandleAriaExpandedChanged() {
// Find if a parent of this object should handle aria-expanded changes.
AXObject* container_parent = ParentObject();
while (container_parent) {
bool found_parent = false;
switch (container_parent->RoleValue()) {
case ax::mojom::blink::Role::kLayoutTable:
case ax::mojom::blink::Role::kTree:
case ax::mojom::blink::Role::kTreeGrid:
case ax::mojom::blink::Role::kGrid:
case ax::mojom::blink::Role::kTable:
found_parent = true;
break;
default:
break;
}
if (found_parent)
break;
container_parent = container_parent->ParentObject();
}
// Post that the row count changed.
if (container_parent) {
AXObjectCache().PostNotification(container_parent,
ax::mojom::blink::Event::kRowCountChanged);
}
// Post that the specific row either collapsed or expanded.
AccessibilityExpanded expanded = IsExpanded();
if (!expanded)
return;
if (RoleValue() == ax::mojom::blink::Role::kRow ||
RoleValue() == ax::mojom::blink::Role::kTreeItem) {
ax::mojom::blink::Event notification =
ax::mojom::blink::Event::kRowExpanded;
if (expanded == kExpandedCollapsed)
notification = ax::mojom::blink::Event::kRowCollapsed;
AXObjectCache().PostNotification(this, notification);
} else {
AXObjectCache().PostNotification(this,
ax::mojom::blink::Event::kExpandedChanged);
}
}
void AXNodeObject::HandleActiveDescendantChanged() {
if (!GetLayoutObject() || !GetNode() || !GetDocument())
return;
Node* focused_node = GetDocument()->FocusedElement();
if (focused_node == GetNode()) {
AXObject* active_descendant = ActiveDescendant();
if (active_descendant) {
if (active_descendant->IsSelectedFromFocus()) {
// In single selection containers, selection follows focus, so a
// selection changed event must be fired. This ensures the AT is
// notified that the selected state has changed, so that it does not
// read "unselected" as the user navigates through the items.
AXObjectCache().HandleAriaSelectedChangedWithCleanLayout(
active_descendant->GetNode());
} else if (active_descendant->RoleValue() ==
ax::mojom::blink::Role::kRow) {
// Active descendant rows must be marked dirty because that can make
// them gain accessible name from contents
// (see AXObject::SupportsNameFromContents).
AXObjectCache().MarkAXObjectDirtyWithCleanLayout(active_descendant);
}
}
// Mark this node dirty. AXEventGenerator will automatically infer
// that the active descendant changed.
AXObjectCache().MarkAXObjectDirtyWithCleanLayout(this);
}
}
AXObject::AXObjectVector AXNodeObject::ErrorMessage() const {
if (GetInvalidState() == ax::mojom::blink::InvalidState::kFalse)
return AXObjectVector();
AXObjectVector aria_error_messages =
RelationVectorFromAria(html_names::kAriaErrormessageAttr);
if (aria_error_messages.size() > 0) {
return aria_error_messages;
}
AXObjectVector html_error_messages = ErrorMessageFromHTML();
if (html_error_messages.size() > 0) {
return html_error_messages;
}
return AXObjectVector();
}
AXObject::AXObjectVector AXNodeObject::RelationVectorFromAria(
const QualifiedName& attr_name) const {
Element* el = GetElement();
if (!el) {
return AXObjectVector();
}
const GCedHeapVector<Member<Element>>* elements_from_attribute =
ElementsFromAttributeOrInternals(el, attr_name);
if (!elements_from_attribute) {
return AXObjectVector();
}
AXObjectVector objects;
for (Element* element : *elements_from_attribute) {
AXObject* obj = AXObjectCache().Get(element);
if (obj && !obj->IsIgnored()) {
objects.push_back(obj);
}
}
return objects;
}
AXObject::AXObjectVector AXNodeObject::ErrorMessageFromHTML() const {
// This can only be visible for a focused
// control. Corollary: if there is a visible validationMessage alert box, then
// it is related to the current focus.
if (this != AXObjectCache().FocusedObject()) {
return AXObjectVector();
}
AXObject* native_error_message =
AXObjectCache().ValidationMessageObjectIfInvalid();
if (native_error_message && !native_error_message->IsDetached()) {
CHECK_GE(native_error_message->IndexInParent(), 0);
return AXObjectVector({native_error_message});
}
return AXObjectVector();
}
String AXNodeObject::TextAlternativeFromTooltip(
ax::mojom::blink::NameFrom& name_from,
NameSources* name_sources,
bool* found_text_alternative,
String* text_alternative,
AXRelatedObjectVector* related_objects) const {
if (!GetElement()) {
return String();
}
name_from = ax::mojom::blink::NameFrom::kTitle;
const AtomicString& title = GetElement()->FastGetAttribute(kTitleAttr);
String title_text = TextAlternativeFromTitleAttribute(
title, name_from, name_sources, found_text_alternative);
// Do not use if empty or if redundant with inner text.
if (!title_text.empty()) {
*text_alternative = title_text;
return title_text;
}
// First try for interest for, then for hint popover.
// TODO(accessibility) Consider only using interest for.
AXObject* popover_ax_object = nullptr;
if (RuntimeEnabledFeatures::HTMLInterestForAttributeEnabled(
GetElement()->GetDocument().GetExecutionContext())) {
popover_ax_object = AXObjectCache().Get(GetElement()->InterestForElement());
}
if (popover_ax_object) {
DCHECK(RuntimeEnabledFeatures::HTMLInterestForAttributeEnabled(
GetElement()->GetDocument().GetExecutionContext()));
name_from = ax::mojom::blink::NameFrom::kInterestFor;
} else {
auto* form_control = DynamicTo<HTMLFormControlElement>(GetElement());
if (!form_control) {
return String();
}
auto popover_target = form_control->popoverTargetElement();
if (!popover_target.popover ||
popover_target.popover->PopoverType() != PopoverValueType::kHint) {
return String();
}
popover_ax_object = AXObjectCache().Get(popover_target.popover);
name_from = ax::mojom::blink::NameFrom::kPopoverTarget;
}
if (name_sources) {
name_sources->push_back(
NameSource(*found_text_alternative, html_names::kPopovertargetAttr));
name_sources->back().type = name_from;
}
// Hint popovers and interest fors are used for text if and only if all of
// the contents are plain, e.g. have no interesting semantic or interactive
// elements. Otherwise, the hint will be exposed via the kDetails
// relationship. The motivation for this is that by reusing the simple
// mechanism of titles, screen reader users can easily access the information
// of plain hints without having to navigate to it, making the content more
// accessible. However, in the case of rich hints, a kDetails relationship is
// required to ensure that users are able to access and interact with the hint
// as they can navigate to it using commands.
if (!popover_ax_object || !popover_ax_object->IsPlainContent()) {
return String();
}
AXObjectSet visited;
String popover_text =
RecursiveTextAlternative(*popover_ax_object, popover_ax_object, visited);
// Do not use if redundant with inner text.
if (popover_text.StripWhiteSpace() ==
GetElement()->GetInnerTextWithoutUpdate().StripWhiteSpace()) {
return String();
}
*text_alternative = popover_text;
if (related_objects) {
related_objects->push_back(MakeGarbageCollected<NameSourceRelatedObject>(
popover_ax_object, popover_text));
}
if (name_sources) {
NameSource& source = name_sources->back();
source.related_objects = *related_objects;
source.text = *text_alternative;
*found_text_alternative = true;
}
return popover_text;
}
String AXNodeObject::TextAlternativeFromTitleAttribute(
const AtomicString& title,
ax::mojom::blink::NameFrom& name_from,
NameSources* name_sources,
bool* found_text_alternative) const {
DCHECK(GetElement());
String text_alternative;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative, kTitleAttr));
name_sources->back().type = name_from;
}
name_from = ax::mojom::blink::NameFrom::kTitle;
if (!title.IsNull() &&
String(title).StripWhiteSpace() !=
GetElement()->GetInnerTextWithoutUpdate().StripWhiteSpace()) {
text_alternative = title;
if (name_sources) {
NameSource& source = name_sources->back();
source.attribute_value = title;
source.attribute_value = title;
source.text = text_alternative;
*found_text_alternative = true;
}
}
return text_alternative;
}
// Based on
// https://www.w3.org/TR/html-aam-1.0/#accessible-name-and-description-computation
String AXNodeObject::NativeTextAlternative(
AXObjectSet& visited,
ax::mojom::blink::NameFrom& name_from,
AXRelatedObjectVector* related_objects,
NameSources* name_sources,
bool* found_text_alternative) const {
if (!GetNode())
return String();
// If nameSources is non-null, relatedObjects is used in filling it in, so it
// must be non-null as well.
if (name_sources)
DCHECK(related_objects);
String text_alternative;
AXRelatedObjectVector local_related_objects;
if (auto* option_element = DynamicTo<HTMLOptionElement>(GetNode())) {
if (option_element->HasOneTextChild()) {
// Use the DisplayLabel() method if there are no interesting children.
// If there are interesting children, fall through and compute the name
// from contents rather, so that descendant markup is respected.
name_from = ax::mojom::blink::NameFrom::kContents;
text_alternative = option_element->DisplayLabel();
if (!text_alternative.empty()) {
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative));
name_sources->back().type = name_from;
name_sources->back().text = text_alternative;
*found_text_alternative = true;
}
return text_alternative;
}
}
}
if (auto* opt_group_element = DynamicTo<HTMLOptGroupElement>(GetNode())) {
name_from = ax::mojom::blink::NameFrom::kAttribute;
text_alternative = opt_group_element->GroupLabelText();
if (!text_alternative.empty()) {
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative));
name_sources->back().type = name_from;
name_sources->back().text = text_alternative;
*found_text_alternative = true;
}
return text_alternative;
}
}
// 5.1/5.5 Text inputs, Other labelable Elements
// If you change this logic, update AXNodeObject::IsNameFromLabelElement, too.
auto* html_element = DynamicTo<HTMLElement>(GetNode());
if (html_element && html_element->IsLabelable()) {
name_from = ax::mojom::blink::NameFrom::kRelatedElement;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative));
name_sources->back().type = name_from;
name_sources->back().native_source = kAXTextFromNativeHTMLLabel;
}
LabelsNodeList* labels = nullptr;
if (AXObjectCache().MayHaveHTMLLabel(*html_element))
labels = html_element->labels();
if (labels && labels->length() > 0) {
HeapVector<Member<Element>> label_elements;
for (unsigned label_index = 0; label_index < labels->length();
++label_index) {
Element* label = labels->item(label_index);
if (name_sources) {
if (!label->FastGetAttribute(html_names::kForAttr).empty() &&
label->FastGetAttribute(html_names::kForAttr) ==
html_element->GetIdAttribute()) {
name_sources->back().native_source = kAXTextFromNativeHTMLLabelFor;
} else {
name_sources->back().native_source =
kAXTextFromNativeHTMLLabelWrapped;
}
}
label_elements.push_back(label);
}
text_alternative =
TextFromElements(false, visited, label_elements, related_objects);
if (!text_alternative.IsNull()) {
*found_text_alternative = true;
if (name_sources) {
NameSource& source = name_sources->back();
source.related_objects = *related_objects;
source.text = text_alternative;
} else {
return text_alternative.StripWhiteSpace();
}
} else if (name_sources) {
name_sources->back().invalid = true;
}
}
}
// 5.2 input type="button", input type="submit" and input type="reset"
const auto* input_element = DynamicTo<HTMLInputElement>(GetNode());
if (input_element && input_element->IsTextButton()) {
// value attribute.
name_from = ax::mojom::blink::NameFrom::kValue;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative, kValueAttr));
name_sources->back().type = name_from;
}
String value = input_element->Value();
if (!value.IsNull()) {
text_alternative = value;
if (name_sources) {
NameSource& source = name_sources->back();
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
// Get default value if object is not laid out.
// If object is laid out, it will have a layout object for the label.
if (!GetLayoutObject()) {
String default_label = input_element->ValueOrDefaultLabel();
if (value.IsNull() && !default_label.IsNull()) {
// default label
name_from = ax::mojom::blink::NameFrom::kContents;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative));
name_sources->back().type = name_from;
}
text_alternative = default_label;
if (name_sources) {
NameSource& source = name_sources->back();
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
}
return text_alternative;
}
// 5.3 input type="image"
if (input_element &&
input_element->getAttribute(kTypeAttr) == input_type_names::kImage) {
// alt attr
const AtomicString& alt = input_element->getAttribute(kAltAttr);
const bool is_empty = alt.empty() && !alt.IsNull();
name_from = is_empty ? ax::mojom::blink::NameFrom::kAttributeExplicitlyEmpty
: ax::mojom::blink::NameFrom::kAttribute;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative, kAltAttr));
name_sources->back().type = name_from;
}
if (!alt.empty()) {
text_alternative = alt;
if (name_sources) {
NameSource& source = name_sources->back();
source.attribute_value = alt;
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
// value attribute.
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative, kValueAttr));
name_sources->back().type = name_from;
}
name_from = ax::mojom::blink::NameFrom::kAttribute;
String value = input_element->Value();
if (!value.IsNull()) {
text_alternative = value;
if (name_sources) {
NameSource& source = name_sources->back();
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
// title attr or popover
String resulting_text = TextAlternativeFromTooltip(
name_from, name_sources, found_text_alternative, &text_alternative,
related_objects);
if (!resulting_text.empty()) {
if (name_sources) {
text_alternative = resulting_text;
} else {
return resulting_text;
}
}
// localised default value ("Submit")
name_from = ax::mojom::blink::NameFrom::kValue;
text_alternative =
input_element->GetLocale().QueryString(IDS_FORM_SUBMIT_LABEL);
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative, kTypeAttr));
NameSource& source = name_sources->back();
source.attribute_value = input_element->getAttribute(kTypeAttr);
source.type = name_from;
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
return text_alternative;
}
// <input type="file">
if (input_element &&
input_element->FormControlType() == FormControlType::kInputFile) {
// Append label of inner shadow root button + value attribute.
name_from = ax::mojom::blink::NameFrom::kContents;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative, kValueAttr));
name_sources->back().type = name_from;
}
if (ShadowRoot* shadow_root = input_element->UserAgentShadowRoot()) {
text_alternative =
To<HTMLInputElement>(shadow_root->firstElementChild())->Value();
if (name_sources) {
NameSource& source = name_sources->back();
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
}
// 5.1 Text inputs - step 3 (placeholder attribute)
if (html_element && html_element->IsTextControl()) {
// title attr
String resulting_text = TextAlternativeFromTooltip(
name_from, name_sources, found_text_alternative, &text_alternative,
related_objects);
if (!resulting_text.empty()) {
if (name_sources) {
text_alternative = resulting_text;
} else {
return resulting_text;
}
}
name_from = ax::mojom::blink::NameFrom::kPlaceholder;
if (name_sources) {
name_sources->push_back(
NameSource(*found_text_alternative, html_names::kPlaceholderAttr));
NameSource& source = name_sources->back();
source.type = name_from;
}
const String placeholder = PlaceholderFromNativeAttribute();
if (!placeholder.empty()) {
text_alternative = placeholder;
if (name_sources) {
NameSource& source = name_sources->back();
source.text = text_alternative;
source.attribute_value =
html_element->FastGetAttribute(html_names::kPlaceholderAttr);
*found_text_alternative = true;
} else {
return text_alternative;
}
}
}
// Also check for aria-placeholder.
if (IsTextField()) {
name_from = ax::mojom::blink::NameFrom::kPlaceholder;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative,
html_names::kAriaPlaceholderAttr));
NameSource& source = name_sources->back();
source.type = name_from;
}
const AtomicString& aria_placeholder =
AriaAttribute(html_names::kAriaPlaceholderAttr);
if (!aria_placeholder.empty()) {
text_alternative = aria_placeholder;
if (name_sources) {
NameSource& source = name_sources->back();
source.text = text_alternative;
source.attribute_value = aria_placeholder;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
return text_alternative;
}
// 5.8 img or area Element
if (IsA<HTMLImageElement>(GetNode()) || IsA<HTMLAreaElement>(GetNode())) {
// alt
const AtomicString& alt = GetElement()->FastGetAttribute(kAltAttr);
const bool is_empty = alt.empty() && !alt.IsNull();
name_from = is_empty ? ax::mojom::blink::NameFrom::kAttributeExplicitlyEmpty
: ax::mojom::blink::NameFrom::kAttribute;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative, kAltAttr));
name_sources->back().type = name_from;
}
if (!alt.empty()) {
text_alternative = alt;
if (name_sources) {
NameSource& source = name_sources->back();
source.attribute_value = alt;
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
return text_alternative;
}
// 5.9 table Element
if (auto* table_element = DynamicTo<HTMLTableElement>(GetNode())) {
// caption
name_from = ax::mojom::blink::NameFrom::kCaption;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative));
name_sources->back().type = name_from;
name_sources->back().native_source = kAXTextFromNativeHTMLTableCaption;
}
HTMLTableCaptionElement* caption = table_element->caption();
if (caption) {
AXObject* caption_ax_object = AXObjectCache().Get(caption);
if (caption_ax_object) {
text_alternative =
RecursiveTextAlternative(*caption_ax_object, nullptr, visited);
if (related_objects) {
local_related_objects.push_back(
MakeGarbageCollected<NameSourceRelatedObject>(caption_ax_object,
text_alternative));
*related_objects = local_related_objects;
local_related_objects.clear();
}
if (name_sources) {
NameSource& source = name_sources->back();
source.related_objects = *related_objects;
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
}
// summary
name_from = ax::mojom::blink::NameFrom::kAttribute;
if (name_sources) {
name_sources->push_back(
NameSource(*found_text_alternative, html_names::kSummaryAttr));
name_sources->back().type = name_from;
}
const AtomicString& summary =
GetElement()->FastGetAttribute(html_names::kSummaryAttr);
if (!summary.IsNull()) {
text_alternative = summary;
if (name_sources) {
NameSource& source = name_sources->back();
source.attribute_value = summary;
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
return text_alternative;
}
// Per SVG AAM 1.0's modifications to 2D of this algorithm.
if (GetNode()->IsSVGElement()) {
name_from = ax::mojom::blink::NameFrom::kRelatedElement;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative));
name_sources->back().type = name_from;
name_sources->back().native_source = kAXTextFromNativeTitleElement;
}
auto* container_node = To<ContainerNode>(GetNode());
Element* title = ElementTraversal::FirstChild(
*container_node, HasTagName(svg_names::kTitleTag));
if (title) {
// TODO(accessibility): In most cases <desc> and <title> can
// participate in the recursive text alternative calculation. However
// when the <desc> or <title> is the child of a <use>,
// |AXObjectCache::GetOrCreate| will fail when
// |AXObject::ComputeNonARIAParent| returns null because the <use>
// element's subtree isn't visited by LayoutTreeBuilderTraversal. In
// addition, while aria-label and other text alternative sources are
// are technically valid on SVG <desc> and <title>, it is not clear if
// user agents must expose their values. Therefore until we hear
// otherwise, just use the inner text. See
// https://github.com/w3c/svgwg/issues/867
text_alternative = title->GetInnerTextWithoutUpdate();
if (!text_alternative.empty()) {
if (name_sources) {
NameSource& source = name_sources->back();
source.text = text_alternative;
source.related_objects = *related_objects;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
}
// The SVG-AAM says that the xlink:title participates as a name source
// for links.
if (IsA<SVGAElement>(GetNode())) {
name_from = ax::mojom::blink::NameFrom::kAttribute;
if (name_sources) {
name_sources->push_back(
NameSource(*found_text_alternative, xlink_names::kTitleAttr));
name_sources->back().type = name_from;
}
const AtomicString& title_attr =
DynamicTo<Element>(GetNode())->FastGetAttribute(
xlink_names::kTitleAttr);
if (!title_attr.empty()) {
text_alternative = title_attr;
if (name_sources) {
NameSource& source = name_sources->back();
source.text = text_alternative;
source.attribute_value = title_attr;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
}
}
// Fieldset / legend.
if (auto* html_field_set_element =
DynamicTo<HTMLFieldSetElement>(GetNode())) {
name_from = ax::mojom::blink::NameFrom::kRelatedElement;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative));
name_sources->back().type = name_from;
name_sources->back().native_source = kAXTextFromNativeHTMLLegend;
}
HTMLElement* legend = html_field_set_element->Legend();
if (legend) {
AXObject* legend_ax_object = AXObjectCache().Get(legend);
// Avoid an infinite loop
if (legend_ax_object && !visited.Contains(legend_ax_object)) {
text_alternative =
RecursiveTextAlternative(*legend_ax_object, nullptr, visited);
if (related_objects) {
local_related_objects.push_back(
MakeGarbageCollected<NameSourceRelatedObject>(legend_ax_object,
text_alternative));
*related_objects = local_related_objects;
local_related_objects.clear();
}
if (name_sources) {
NameSource& source = name_sources->back();
source.related_objects = *related_objects;
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
}
}
// Document.
if (Document* document = DynamicTo<Document>(GetNode())) {
if (document) {
name_from = ax::mojom::blink::NameFrom::kAttribute;
if (name_sources) {
name_sources->push_back(
NameSource(found_text_alternative, html_names::kAriaLabelAttr));
name_sources->back().type = name_from;
}
if (Element* document_element = document->documentElement()) {
const AtomicString& aria_label =
AriaAttribute(*document_element, html_names::kAriaLabelAttr);
if (!aria_label.empty()) {
text_alternative = aria_label;
if (name_sources) {
NameSource& source = name_sources->back();
source.text = text_alternative;
source.attribute_value = aria_label;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
}
text_alternative = document->title();
bool is_empty_title_element =
text_alternative.empty() && document->TitleElement();
if (is_empty_title_element)
name_from = ax::mojom::blink::NameFrom::kAttributeExplicitlyEmpty;
else
name_from = ax::mojom::blink::NameFrom::kRelatedElement;
if (name_sources) {
name_sources->push_back(NameSource(*found_text_alternative));
NameSource& source = name_sources->back();
source.type = name_from;
source.native_source = kAXTextFromNativeTitleElement;
source.text = text_alternative;
*found_text_alternative = true;
} else {
return text_alternative;
}
}
}
return text_alternative;
}
// static
String AXNodeObject::GetSavedTextAlternativeFromNameSource(
bool found_text_alternative,
ax::mojom::NameFrom& name_from,
AXRelatedObjectVector* related_objects,
NameSources* name_sources) {
name_from = ax::mojom::blink::NameFrom::kNone;
if (!name_sources || !found_text_alternative) {
return String();
}
for (NameSource& name_source : *name_sources) {
if (name_source.text.empty() || name_source.superseded) {
continue;
}
name_from = name_source.type;
if (!name_source.related_objects.empty()) {
*related_objects = name_source.related_objects;
}
return name_source.text;
}
return String();
}
// This is not part of the spec, but we think it's a worthy addition: if the
// labelled input is of type="file", we append the chosen file name to it. We do
// this because this type of input is actually exposed as a button, and buttons
// may not have a "value" field. An unlabelled input is manager later in this
// function, it's named with the default text in the button, 'Choose File', plus
// the file name.
String AXNodeObject::MaybeAppendFileDescriptionToName(
const String& name) const {
const auto* input_element = DynamicTo<HTMLInputElement>(GetNode());
if (!input_element ||
input_element->FormControlType() != FormControlType::kInputFile) {
return name;
}
String displayed_file_path = GetValueForControl();
if (!displayed_file_path.empty()) {
bool is_rtl =
GetTextDirection() == ax::mojom::blink::WritingDirection::kRtl;
return StrCat({name, is_rtl ? " :" : ": ", displayed_file_path});
}
return name;
}
bool AXNodeObject::ShouldIncludeContentInTextAlternative(
bool recursive,
const AXObject* aria_label_or_description_root,
AXObjectSet& visited) const {
if (!aria_label_or_description_root &&
!SupportsNameFromContents(recursive, /*consider_focus*/ true)) {
return false;
}
// Avoid option descendent text.
if (IsA<HTMLSelectElement>(GetNode())) {
return false;
}
// A textfield's name should not include its value (see crbug.com/352665697),
// unless aria-labelledby explicitly references its own content.
//
// Example from aria-labelledby-on-input.html:
// <input id="time" value="10" aria-labelledby="message time unit"/>
//
// When determining the name for the <input>, we parse the list of IDs in
// aria-labelledby. When "time" is reached, aria_label_or_description_root
// points to the element we are naming (the <input>) and 'this' refers to the
// element we are currently traversing, which is the element with id="time"
// (so, aria_label_or_description_root == this). In this case, since the
// author explicitly included the input id, the value of the input should be
// included in the name.
if (IsTextField() && aria_label_or_description_root != this) {
return false;
}
return true;
}
String AXNodeObject::Description(
ax::mojom::blink::NameFrom name_from,
ax::mojom::blink::DescriptionFrom& description_from,
AXObjectVector* description_objects) const {
AXRelatedObjectVector related_objects;
String result =
Description(name_from, description_from, nullptr, &related_objects);
if (description_objects) {
description_objects->clear();
for (NameSourceRelatedObject* related_object : related_objects)
description_objects->push_back(related_object->object);
}
result = result.SimplifyWhiteSpace(IsHTMLSpace<UChar>);
if (RoleValue() == ax::mojom::blink::Role::kSpinButton &&
DatetimeAncestor()) {
// Fields inside a datetime control need to merge the field description
// with the description of the <input> element.
const AXObject* datetime_ancestor = DatetimeAncestor();
ax::mojom::blink::NameFrom datetime_ancestor_name_from;
datetime_ancestor->GetName(datetime_ancestor_name_from, nullptr, nullptr);
if (description_objects)
description_objects->clear();
String ancestor_description = DatetimeAncestor()->Description(
datetime_ancestor_name_from, description_from, description_objects);
if (!result.empty() && !ancestor_description.empty())
return StrCat({result, " ", ancestor_description});
if (!ancestor_description.empty())
return ancestor_description;
}
return result;
}
// Based on
// http://rawgit.com/w3c/aria/master/html-aam/html-aam.html#accessible-name-and-description-calculation
String AXNodeObject::Description(
ax::mojom::blink::NameFrom name_from,
ax::mojom::blink::DescriptionFrom& description_from,
DescriptionSources* description_sources,
AXRelatedObjectVector* related_objects) const {
// If descriptionSources is non-null, relatedObjects is used in filling it in,
// so it must be non-null as well.
// Important: create a DescriptionSource for every *potential* description
// source, even if it ends up not being present.
// When adding a new description_from type:
// * Also add it to AXValueNativeSourceType here:
// blink/public/devtools_protocol/browser_protocol.pdl
// * Update InspectorTypeBuilderHelper to map the new enum to
// the browser_protocol enum in NativeSourceType():
// blink/renderer/modules/accessibility/inspector_type_builder_helper.cc
// * Update devtools_frontend to add a new string for the new type of
// description. See AXNativeSourceTypes at:
// devtools-frontend/src/front_end/accessibility/AccessibilityStrings.js
if (description_sources)
DCHECK(related_objects);
if (!GetNode())
return String();
String description;
bool found_description = false;
description_from = ax::mojom::blink::DescriptionFrom::kRelatedElement;
if (description_sources) {
description_sources->push_back(
DescriptionSource(found_description, html_names::kAriaDescribedbyAttr));
description_sources->back().type = description_from;
}
// aria-describedby overrides any other accessible description, from:
// http://rawgit.com/w3c/aria/master/html-aam/html-aam.html
Element* element = GetElement();
if (!element)
return String();
const GCedHeapVector<Member<Element>>* elements_from_attribute =
ElementsFromAttributeOrInternals(element,
html_names::kAriaDescribedbyAttr);
if (elements_from_attribute) {
// TODO(meredithl): Determine description sources when |aria_describedby| is
// the empty string, in order to make devtools work with attr-associated
// elements.
if (description_sources) {
description_sources->back().attribute_value =
AriaAttribute(html_names::kAriaDescribedbyAttr);
}
AXObjectSet visited;
description = TextFromElements(true, visited, *elements_from_attribute,
related_objects);
if (!description.IsNull()) {
if (description_sources) {
DescriptionSource& source = description_sources->back();
source.type = description_from;
source.related_objects = *related_objects;
source.text = description;
found_description = true;
} else {
return description;
}
} else if (description_sources) {
description_sources->back().invalid = true;
}
}
// aria-description overrides any HTML-based accessible description,
// but not aria-describedby.
const AtomicString& aria_desc =
AriaAttribute(html_names::kAriaDescriptionAttr);
if (aria_desc) {
description_from = ax::mojom::blink::DescriptionFrom::kAriaDescription;
description = aria_desc;
if (description_sources) {
found_description = true;
description_sources->back().text = description;
} else {
return description;
}
}
// SVG-AAM specifies additional description sources when ARIA sources have not
// been found. https://w3c.github.io/svg-aam/#mapping_additional_nd
if (IsA<SVGElement>(GetNode())) {
String svg_description = SVGDescription(
name_from, description_from, description_sources, related_objects);
if (!svg_description.empty()) {
return svg_description;
}
}
const auto* input_element = DynamicTo<HTMLInputElement>(GetNode());
// value, 5.2.2 from: https://www.w3.org/TR/html-aam-1.0/
if (name_from != ax::mojom::blink::NameFrom::kValue && input_element &&
input_element->IsTextButton()) {
description_from = ax::mojom::blink::DescriptionFrom::kButtonLabel;
if (description_sources) {
description_sources->push_back(
DescriptionSource(found_description, kValueAttr));
description_sources->back().type = description_from;
}
String value = input_element->Value();
if (!value.IsNull()) {
description = value;
if (description_sources) {
DescriptionSource& source = description_sources->back();
source.text = description;
found_description = true;
} else {
return description;
}
}
}
if (RoleValue() == ax::mojom::blink::Role::kRuby) {
description_from = ax::mojom::blink::DescriptionFrom::kRubyAnnotation;
if (description_sources) {
description_sources->push_back(DescriptionSource(found_description));
description_sources->back().type = description_from;
description_sources->back().native_source =
kAXTextFromNativeHTMLRubyAnnotation;
}
AXObject* ruby_annotation_ax_object = nullptr;
for (const auto& child : children_) {
if (child->RoleValue() == ax::mojom::blink::Role::kRubyAnnotation &&
child->GetNode() &&
child->GetNode()->HasTagName(html_names::kRtTag)) {
ruby_annotation_ax_object = child;
break;
}
}
if (ruby_annotation_ax_object) {
AXObjectSet visited;
description =
RecursiveTextAlternative(*ruby_annotation_ax_object, this, visited);
if (related_objects) {
related_objects->push_back(
MakeGarbageCollected<NameSourceRelatedObject>(
ruby_annotation_ax_object, description));
}
if (description_sources) {
DescriptionSource& source = description_sources->back();
source.related_objects = *related_objects;
source.text = description;
found_description = true;
} else {
return description;
}
}
}
// table caption, 5.9.2 from: https://www.w3.org/TR/html-aam-1.0/
auto* table_element = DynamicTo<HTMLTableElement>(element);
if (name_from != ax::mojom::blink::NameFrom::kCaption && table_element) {
description_from = ax::mojom::blink::DescriptionFrom::kTableCaption;
if (description_sources) {
description_sources->push_back(DescriptionSource(found_description));
description_sources->back().type = description_from;
description_sources->back().native_source =
kAXTextFromNativeHTMLTableCaption;
}
HTMLTableCaptionElement* caption = table_element->caption();
if (caption) {
AXObject* caption_ax_object = AXObjectCache().Get(caption);
if (caption_ax_object) {
AXObjectSet visited;
description =
RecursiveTextAlternative(*caption_ax_object, nullptr, visited);
if (related_objects) {
related_objects->push_back(
MakeGarbageCollected<NameSourceRelatedObject>(caption_ax_object,
description));
}
if (description_sources) {
DescriptionSource& source = description_sources->back();
source.related_objects = *related_objects;
source.text = description;
found_description = true;
} else {
return description;
}
}
}
}
// summary, 5.8.2 from: https://www.w3.org/TR/html-aam-1.0/
if (name_from != ax::mojom::blink::NameFrom::kContents &&
IsA<HTMLSummaryElement>(GetNode())) {
description_from = ax::mojom::blink::DescriptionFrom::kSummary;
if (description_sources) {
description_sources->push_back(DescriptionSource(found_description));
description_sources->back().type = description_from;
}
AXObjectSet visited;
description = TextFromDescendants(visited, nullptr, false);
if (!description.empty()) {
if (description_sources) {
found_description = true;
description_sources->back().text = description;
} else {
return description;
}
}
}
// title attribute, from: https://www.w3.org/TR/html-aam-1.0/
if (name_from != ax::mojom::blink::NameFrom::kTitle) {
description_from = ax::mojom::blink::DescriptionFrom::kTitle;
if (description_sources) {
description_sources->push_back(
DescriptionSource(found_description, kTitleAttr));
description_sources->back().type = description_from;
}
const AtomicString& title = element->FastGetAttribute(kTitleAttr);
if (!title.empty() &&
String(title).StripWhiteSpace() !=
element->GetInnerTextWithoutUpdate().StripWhiteSpace()) {
description = title;
if (description_sources) {
found_description = true;
description_sources->back().text = description;
} else {
return description;
}
}
}
// For form controls that act as interest for triggering elements, use
// the target for a description if it only contains plain contents.
if (RuntimeEnabledFeatures::HTMLInterestForAttributeEnabled(
element->GetDocument().GetExecutionContext()) &&
name_from != ax::mojom::blink::NameFrom::kInterestFor) {
if (Element* target = element->InterestForElement()) {
DCHECK(RuntimeEnabledFeatures::HTMLInterestForAttributeEnabled(
element->GetDocument().GetExecutionContext()));
description_from = ax::mojom::blink::DescriptionFrom::kInterestFor;
if (description_sources) {
description_sources->push_back(
DescriptionSource(found_description, html_names::kInterestforAttr));
description_sources->back().type = description_from;
}
AXObject* interest_ax_object = AXObjectCache().Get(target);
if (interest_ax_object && interest_ax_object->IsPlainContent()) {
AXObjectSet visited;
description = RecursiveTextAlternative(*interest_ax_object,
interest_ax_object, visited);
if (related_objects) {
related_objects->push_back(
MakeGarbageCollected<NameSourceRelatedObject>(interest_ax_object,
description));
}
if (description_sources) {
DescriptionSource& source = description_sources->back();
source.related_objects = *related_objects;
source.text = description;
found_description = true;
} else {
return description;
}
}
}
}
// For form controls that act as triggering elements for popovers of type
// kHint, then set aria-describedby to the popover.
if (name_from != ax::mojom::blink::NameFrom::kPopoverTarget) {
if (auto* form_control = DynamicTo<HTMLFormControlElement>(element)) {
auto popover_target = form_control->popoverTargetElement();
if (popover_target.popover &&
popover_target.popover->PopoverType() == PopoverValueType::kHint) {
description_from = ax::mojom::blink::DescriptionFrom::kPopoverTarget;
if (description_sources) {
description_sources->push_back(DescriptionSource(
found_description, html_names::kPopovertargetAttr));
description_sources->back().type = description_from;
}
AXObject* popover_ax_object =
AXObjectCache().Get(popover_target.popover);
if (popover_ax_object && popover_ax_object->IsPlainContent()) {
AXObjectSet visited;
description = RecursiveTextAlternative(*popover_ax_object,
popover_ax_object, visited);
if (related_objects) {
related_objects->push_back(
MakeGarbageCollected<NameSourceRelatedObject>(popover_ax_object,
description));
}
if (description_sources) {
DescriptionSource& source = description_sources->back();
source.related_objects = *related_objects;
source.text = description;
found_description = true;
} else {
return description;
}
}
}
}
}
// There was a name, but it is prohibited for this role. Move to description.
if (name_from == ax::mojom::blink::NameFrom::kProhibited) {
description_from = ax::mojom::blink::DescriptionFrom::kProhibitedNameRepair;
ax::mojom::blink::NameFrom orig_name_from_without_prohibited;
HeapHashSet<Member<const AXObject>> visited;
description = TextAlternative(false, nullptr, visited,
orig_name_from_without_prohibited,
related_objects, nullptr);
DCHECK(!description.empty());
if (description_sources) {
description_sources->push_back(DescriptionSource(found_description));
DescriptionSource& source = description_sources->back();
source.type = description_from;
source.related_objects = *related_objects;
source.text = description;
found_description = true;
} else {
return description;
}
}
description_from = ax::mojom::blink::DescriptionFrom::kNone;
if (found_description) {
DCHECK(description_sources)
<< "Should only reach here if description_sources are tracked";
// Use the first non-null description.
// TODO(accessibility) Why do we need to check superceded if that will
// always be the first one?
for (DescriptionSource& description_source : *description_sources) {
if (!description_source.text.IsNull() && !description_source.superseded) {
description_from = description_source.type;
if (!description_source.related_objects.empty())
*related_objects = description_source.related_objects;
return description_source.text;
}
}
}
return String();
}
String AXNodeObject::SVGDescription(
ax::mojom::blink::NameFrom name_from,
ax::mojom::blink::DescriptionFrom& description_from,
DescriptionSources* description_sources,
AXRelatedObjectVector* related_objects) const {
DCHECK(IsA<SVGElement>(GetNode()));
String description;
bool found_description = false;
Element* element = GetElement();
description_from = ax::mojom::blink::DescriptionFrom::kSvgDescElement;
if (description_sources) {
description_sources->push_back(DescriptionSource(found_description));
description_sources->back().type = description_from;
description_sources->back().native_source = kAXTextFromNativeSVGDescElement;
}
if (Element* desc = ElementTraversal::FirstChild(
*element, HasTagName(svg_names::kDescTag))) {
// TODO(accessibility): In most cases <desc> and <title> can participate in
// the recursive text alternative calculation. However when the <desc> or
// <title> is the child of a <use>, |AXObjectCache::GetOrCreate| will fail
// when |AXObject::ComputeNonARIAParent| returns null because the <use>
// element's subtree isn't visited by LayoutTreeBuilderTraversal. In
// addition, while aria-label and other text alternative sources are are
// technically valid on SVG <desc> and <title>, it is not clear if user
// agents must expose their values. Therefore until we hear otherwise, just
// use the inner text. See https://github.com/w3c/svgwg/issues/867
description = desc->GetInnerTextWithoutUpdate();
if (!description.empty()) {
if (description_sources) {
DescriptionSource& source = description_sources->back();
source.related_objects = *related_objects;
source.text = description;
found_description = true;
} else {
return description;
}
}
}
// If we haven't found a description source yet and the title is present,
// SVG-AAM states to use the <title> if ARIA label attributes are used to
// provide the accessible name.
if (IsNameFromAriaAttribute(element)) {
description_from = ax::mojom::blink::DescriptionFrom::kTitle;
if (description_sources) {
description_sources->push_back(DescriptionSource(found_description));
description_sources->back().type = description_from;
description_sources->back().native_source = kAXTextFromNativeTitleElement;
}
if (Element* title = ElementTraversal::FirstChild(
*element, HasTagName(svg_names::kTitleTag))) {
// TODO(accessibility): In most cases <desc> and <title> can participate
// in the recursive text alternative calculation. However when the <desc>
// or <title> is the child of a <use>, |AXObjectCache::GetOrCreate| will
// fail when |AXObject::ComputeNonARIAParent| returns null because the
// <use> element's subtree isn't visited by LayoutTreeBuilderTraversal. In
// addition, while aria-label and other text alternative sources are are
// technically valid on SVG <desc> and <title>, it is not clear if user
// agents must expose their values. Therefore until we hear otherwise,
// just use the inner text. See https://github.com/w3c/svgwg/issues/867
description = title->GetInnerTextWithoutUpdate();
if (!description.empty()) {
if (description_sources) {
DescriptionSource& source = description_sources->back();
source.related_objects = *related_objects;
source.text = description;
found_description = true;
} else {
return description;
}
}
}
}
// In the case of an SVG <a>, the last description source is the xlink:title
// attribute, if it didn't serve as the name source.
if (IsA<SVGAElement>(GetNode()) &&
name_from != ax::mojom::blink::NameFrom::kAttribute) {
description_from = ax::mojom::blink::DescriptionFrom::kTitle;
const AtomicString& title_attr =
DynamicTo<Element>(GetNode())->FastGetAttribute(
xlink_names::kTitleAttr);
if (!title_attr.empty()) {
description = title_attr;
if (description_sources) {
found_description = true;
description_sources->back().text = description;
} else {
return description;
}
}
}
return String();
}
String AXNodeObject::Placeholder(ax::mojom::blink::NameFrom name_from) const {
if (name_from == ax::mojom::blink::NameFrom::kPlaceholder)
return String();
Node* node = GetNode();
if (!node || !node->IsHTMLElement())
return String();
String native_placeholder = PlaceholderFromNativeAttribute();
if (!native_placeholder.empty())
return native_placeholder;
const AtomicString& aria_placeholder =
AriaAttribute(html_names::kAriaPlaceholderAttr);
if (!aria_placeholder.empty())
return aria_placeholder;
return String();
}
String AXNodeObject::Title(ax::mojom::blink::NameFrom name_from) const {
if (name_from == ax::mojom::blink::NameFrom::kTitle)
return String(); // Already exposed the title in the name field.
return GetTitle(GetElement());
}
String AXNodeObject::PlaceholderFromNativeAttribute() const {
Node* node = GetNode();
if (!node || !blink::IsTextControl(*node))
return String();
return ToTextControl(node)->StrippedPlaceholder();
}
String AXNodeObject::GetValueContributionToName(AXObjectSet& visited) const {
if (IsTextField())
return SlowGetValueForControlIncludingContentEditable();
if (IsRangeValueSupported()) {
const AtomicString& aria_valuetext =
AriaAttribute(html_names::kAriaValuetextAttr);
if (aria_valuetext) {
return aria_valuetext.GetString();
}
float value;
if (ValueForRange(&value))
return String::Number(value);
}
// "If the embedded control has role combobox or listbox, return the text
// alternative of the chosen option."
if (UseNameFromSelectedOption()) {
AXObjectVector selected_options;
SelectedOptions(selected_options);
if (selected_options.size() == 0) {
// Per https://www.w3.org/TR/wai-aria/#combobox, a combobox gets its
// value in the following way:
// "If the combobox element is a host language element that provides a
// value, such as an HTML input element, the value of the combobox is the
// value of that element. Otherwise, the value of the combobox is
// represented by its descendant elements and can be determined using the
// same method used to compute the name of a button from its descendant
// content."
//
// Section 2C of the accname computation steps for the combobox/listbox
// case (https://w3c.github.io/accname/#comp_embedded_control) only
// mentions getting the text alternative from the chosen option, which
// doesn't precisely fit for combobox, but a clarification is coming; see
// https://github.com/w3c/accname/issues/232 and
// https://github.com/w3c/accname/issues/200.
return SlowGetValueForControlIncludingContentEditable(visited);
} else {
StringBuilder accumulated_text;
for (const auto& child : selected_options) {
if (visited.insert(child).is_new_entry) {
if (accumulated_text.length()) {
accumulated_text.Append(" ");
}
accumulated_text.Append(child->ComputedName());
}
}
return accumulated_text.ToString();
}
}
return String();
}
bool AXNodeObject::UseNameFromSelectedOption() const {
// Assumes that the node was reached via recursion in the name calculation.
switch (RoleValue()) {
// Step 2E from: http://www.w3.org/TR/accname-aam-1.1
case ax::mojom::blink::Role::kComboBoxGrouping:
case ax::mojom::blink::Role::kComboBoxMenuButton:
case ax::mojom::blink::Role::kComboBoxSelect:
case ax::mojom::blink::Role::kListBox:
return true;
default:
return false;
}
}
ScrollableArea* AXNodeObject::GetScrollableAreaIfScrollable() const {
if (IsA<Document>(GetNode())) {
return DocumentFrameView()->LayoutViewport();
}
if (auto* box = DynamicTo<LayoutBox>(GetLayoutObject())) {
PaintLayerScrollableArea* scrollable_area = box->GetScrollableArea();
if (scrollable_area && scrollable_area->HasOverflow()) {
return scrollable_area;
}
}
return nullptr;
}
AXObject* AXNodeObject::AccessibilityHitTest(const gfx::Point& point) const {
// Must be called for the document's root or a popup's root.
if (!IsA<Document>(GetNode())) {
return nullptr;
}
CHECK(GetLayoutObject());
// Must be called with lifecycle >= pre-paint clean
DCHECK_GE(GetDocument()->Lifecycle().GetState(),
DocumentLifecycle::kPrePaintClean);
DCHECK(GetLayoutObject()->IsLayoutView());
PaintLayer* layer = To<LayoutBox>(GetLayoutObject())->Layer();
DCHECK(layer);
HitTestRequest request(HitTestRequest::kReadOnly | HitTestRequest::kActive);
HitTestLocation location(point);
HitTestResult hit_test_result = HitTestResult(request, location);
layer->HitTest(location, hit_test_result, PhysicalRect(InfiniteIntRect()));
Node* node = hit_test_result.InnerNode();
if (!node) {
return nullptr;
}
if (auto* area = DynamicTo<HTMLAreaElement>(node)) {
return AccessibilityImageMapHitTest(area, point);
}
if (auto* option = DynamicTo<HTMLOptionElement>(node)) {
node = option->OwnerSelectElement();
if (!node) {
return nullptr;
}
}
// If |node| is in a user-agent shadow tree, reassign it as the host to hide
// details in the shadow tree. Previously this was implemented by using
// Retargeting (https://dom.spec.whatwg.org/#retarget), but this caused
// elements inside regular shadow DOMs to be ignored by screen reader. See
// crbug.com/1111800 and crbug.com/1048959.
const TreeScope& tree_scope = node->GetTreeScope();
if (auto* shadow_root = DynamicTo<ShadowRoot>(tree_scope.RootNode())) {
if (shadow_root->IsUserAgent()) {
node = &shadow_root->host();
}
}
LayoutObject* obj = node->GetLayoutObject();
AXObject* result = AXObjectCache().Get(obj);
if (!result) {
return nullptr;
}
// Allow the element to perform any hit-testing it might need to do to reach
// non-layout children.
result = result->ElementAccessibilityHitTest(point);
while (result && result->IsIgnored()) {
CHECK(!result->IsDetached());
// If this element is the label of a control, a hit test should return the
// control. The label is ignored because it's already reflected in the name.
if (auto* label = DynamicTo<HTMLLabelElement>(result->GetNode())) {
if (HTMLElement* control = label->Control()) {
if (AXObject* ax_control = AXObjectCache().Get(control)) {
result = ax_control;
break;
}
}
}
result = result->ParentObject();
}
return result->IsIncludedInTree() ? result
: result->ParentObjectIncludedInTree();
}
AXObject* AXNodeObject::AccessibilityImageMapHitTest(
HTMLAreaElement* area,
const gfx::Point& point) const {
if (!area) {
return nullptr;
}
AXObject* parent = AXObjectCache().Get(area->ImageElement());
if (!parent) {
return nullptr;
}
PhysicalOffset physical_point(point);
for (const auto& child : parent->ChildrenIncludingIgnored()) {
if (child->GetBoundsInFrameCoordinates().Contains(physical_point)) {
return child.Get();
}
}
return nullptr;
}
AXObject* AXNodeObject::GetFirstInlineBlockOrDeepestInlineAXChildInLayoutTree(
AXObject* start_object,
bool first) const {
if (!start_object) {
return nullptr;
}
// Return the deepest last child that is included.
// Uses LayoutTreeBuildTraversaler to get children, in order to avoid getting
// children unconnected to the line, e.g. via aria-owns. Doing this first also
// avoids the issue that |start_object| may not be included in the tree.
AXObject* result = start_object;
Node* current_node = start_object->GetNode();
while (current_node) {
// If we find a node that is inline-block, we want to return it rather than
// getting the deepest child for that. This is because these are now always
// being included in the tree and the Next/PreviousOnLine could be set on
// the inline-block element. We exclude list markers since those technically
// fulfill the inline-block condition.
AXObject* ax_object = start_object->AXObjectCache().Get(current_node);
if (ax_object && ax_object->IsIncludedInTree() &&
!current_node->IsMarkerPseudoElement()) {
if (ax_object->GetLayoutObject() &&
ax_object->GetLayoutObject()->IsInline() &&
ax_object->GetLayoutObject()->IsAtomicInlineLevel()) {
return ax_object;
}
}
current_node = first ? LayoutTreeBuilderTraversal::FirstChild(*current_node)
: LayoutTreeBuilderTraversal::LastChild(*current_node);
if (!current_node) {
break;
}
AXObject* tentative_child = start_object->AXObjectCache().Get(current_node);
if (tentative_child && tentative_child->IsIncludedInTree()) {
result = tentative_child;
}
}
// Have reached the end of LayoutTreeBuilderTraversal. From here on, traverse
// AXObjects to get deepest descendant of pseudo-element or static text,
// such as an AXInlineTextBox.
// Relevant static text or pseudo-element is always included.
if (!result->IsIncludedInTree()) {
return nullptr;
}
// Already a leaf: return current result.
if (!result->ChildCountIncludingIgnored()) {
return result;
}
// Get deepest AXObject descendant.
return first ? result->DeepestFirstChildIncludingIgnored()
: result->DeepestLastChildIncludingIgnored();
}
void AXNodeObject::MaybeResetCache() const {
uint64_t generation = AXObjectCache().GenerationalCacheId();
if (!generational_cache_) {
generational_cache_ = MakeGarbageCollected<GenerationalCache>();
}
DCHECK(AXObjectCache().IsFrozen());
if (generation != generational_cache_->generation) {
generational_cache_->generation = generation;
generational_cache_->next_on_line = nullptr;
generational_cache_->previous_on_line = nullptr;
} else {
#if DCHECK_IS_ON()
// AXObjects cannot be detached while the tree is frozen.
// These are sanity checks. Limited to DCHECK enabled builds due to
// potential performance impact with to the sheer volume of calls.
if (AXObject* next = generational_cache_->next_on_line) {
CHECK(!next->IsDetached());
}
if (AXObject* previous = generational_cache_->previous_on_line) {
CHECK(!previous->IsDetached());
}
#endif
}
}
void AXNodeObject::GenerationalCache::Trace(Visitor* visitor) const {
visitor->Trace(next_on_line);
visitor->Trace(previous_on_line);
}
AXObject* AXNodeObject::SetNextOnLine(AXObject* next_on_line) const {
CHECK(generational_cache_) << "Must call MaybeResetCache ahead of this call";
generational_cache_->next_on_line = next_on_line;
return next_on_line;
}
AXObject* AXNodeObject::SetPreviousOnLine(AXObject* previous_on_line) const {
CHECK(generational_cache_) << "Must call MaybeResetCache ahead of this call";
generational_cache_->previous_on_line = previous_on_line;
return previous_on_line;
}
AXObject* AXNodeObject::NextOnLine() const {
// If this is the last object on the line, nullptr is returned. Otherwise, all
// inline AXNodeObjects, regardless of role and tree depth, are connected to
// the next inline text box on the same line. If there is no inline text box,
// they are connected to the next leaf AXObject.
DCHECK(!IsDetached());
MaybeResetCache();
if (generational_cache_->next_on_line) {
return generational_cache_->next_on_line;
}
const LayoutObject* layout_object = GetLayoutObject();
if (!layout_object) {
return SetNextOnLine(nullptr);
}
if (!AXObjectCache().IsFrozen() ||
!AXObjectCache().HasCachedDataForNodesOnLine()) {
// TODO(crbug.com/372084397): Solve race condition for web AX API and frozen
// states of accessibility lifecycle.
// Not all serialization data comes from the regular flow (see
// third_party/blink/renderer/modules/accessibility/ax_object_cache_lifecycle.h).
// Some serialization requests come through a special test API (see
// third_party/blink/public/web/web_ax_object.h), which requires us to force
// the data to be computed in case it is not computed yet.
AXObjectCache().ComputeNodesOnLine(layout_object);
}
if (DisplayLockUtilities::LockedAncestorPreventingPaint(*layout_object)) {
return SetNextOnLine(nullptr);
}
if (const auto* list_marker =
GetListMarker(*layout_object, ParentObjectIfPresent())) {
// A list marker should be followed by a list item on the same line.
auto* ax_list_marker = AXObjectCache().Get(list_marker);
if (ax_list_marker) {
AXObject* next_sibling = ax_list_marker->UnignoredNextSiblingSlow();
if (next_sibling) {
return SetNextOnLine(
GetFirstInlineBlockOrDeepestInlineAXChildInLayoutTree(next_sibling,
true));
}
}
return SetNextOnLine(nullptr);
}
if (!ShouldUseLayoutNG(*layout_object)) {
return SetNextOnLine(nullptr);
}
if (!layout_object->IsInLayoutNGInlineFormattingContext()) {
return SetNextOnLine(nullptr);
}
// Obtain the next LayoutObject that is in the same line, which was previously
// computed in `AXObjectCacheImpl::ComputeNodesOnLine()`. If one does not
// exist, move to children and Repeate the process.
// If a LayoutObject is found, in the next loop we compute if it has an
// AXObject that is included in the tree. If so, connect them.
const LayoutObject* next_layout_object = nullptr;
while (layout_object) {
next_layout_object = AXObjectCache().CachedNextOnLine(layout_object);
if (next_layout_object) {
break;
}
const auto* child = layout_object->SlowLastChild();
if (!child) {
break;
}
layout_object = child;
}
while (next_layout_object) {
AXObject* result = AXObjectCache().Get(next_layout_object);
// We want to continue searching for the next inline leaf if the
// current one is inert or aria-hidden.
// We don't necessarily want to keep searching in the case of any ignored
// node, because we anticipate that there might be scenarios where a
// descendant of the ignored node is not ignored and would be returned by
// the call to `GetFirstInlineBlockOrDeepestInlineAXChildInLayoutTree`
bool should_keep_looking =
result ? result->IsInert() || result->IsAriaHidden() : false;
result =
GetFirstInlineBlockOrDeepestInlineAXChildInLayoutTree(result, true);
if (result && !should_keep_looking) {
return SetNextOnLine(result);
}
if (!should_keep_looking) {
break;
}
next_layout_object = AXObjectCache().CachedNextOnLine(next_layout_object);
}
return SetNextOnLine(nullptr);
}
AXObject* AXNodeObject::PreviousOnLine() const {
// If this is the first object on the line, nullptr is returned. Otherwise,
// all inline AXNodeObjects, regardless of role and tree depth, are connected
// to the previous inline text box on the same line. If there is no inline
// text box, they are connected to the previous leaf AXObject.
DCHECK(!IsDetached());
MaybeResetCache();
if (generational_cache_->previous_on_line) {
return generational_cache_->previous_on_line;
}
const LayoutObject* layout_object = GetLayoutObject();
if (!layout_object) {
return SetPreviousOnLine(nullptr);
}
if (!AXObjectCache().IsFrozen() ||
!AXObjectCache().HasCachedDataForNodesOnLine()) {
// See AXNodeObject::NextOnLine() for reasoning of this call.
AXObjectCache().ComputeNodesOnLine(layout_object);
}
if (!ShouldUseLayoutNG(*layout_object)) {
return SetPreviousOnLine(nullptr);
}
if (DisplayLockUtilities::LockedAncestorPreventingPaint(*layout_object)) {
return SetPreviousOnLine(nullptr);
}
AXObject* previous_sibling =
IsIncludedInTree() ? UnignoredPreviousSiblingSlow() : nullptr;
if (previous_sibling && previous_sibling->GetLayoutObject()) {
const auto* list_marker =
GetListMarker(*previous_sibling->GetLayoutObject(),
previous_sibling->ParentObjectIfPresent());
auto* ax_list_marker =
list_marker ? AXObjectCache().Get(list_marker) : nullptr;
if (ax_list_marker && ax_list_marker->GetLayoutObject() &&
ax_list_marker->GetLayoutObject()->IsLayoutOutsideListMarker()) {
// A list item should be preceded by a list marker on the same line.
return SetPreviousOnLine(
GetFirstInlineBlockOrDeepestInlineAXChildInLayoutTree(ax_list_marker,
false));
}
}
if (layout_object->IsLayoutOutsideListMarker() ||
!layout_object->IsInLayoutNGInlineFormattingContext()) {
return SetPreviousOnLine(nullptr);
}
// Obtain the previous LayoutObject that is in the same line, which was
// previously computed in `AXObjectCacheImpl::ComputeNodesOnLine()`. If one
// does not exist, move to children and repeate the process. If a LayoutObject
// is found, in the next loop we compute if it has an AXObject that is
// included in the tree. If so, connect them.
const LayoutObject* previous_layout_object = nullptr;
while (layout_object) {
previous_layout_object =
AXObjectCache().CachedPreviousOnLine(layout_object);
if (previous_layout_object) {
break;
}
const auto* child = layout_object->SlowFirstChild();
if (!child) {
break;
}
layout_object = child;
}
while (previous_layout_object) {
AXObject* result = AXObjectCache().Get(previous_layout_object);
// We want to continue searching for the next inline leaf if the
// current one is inert or aria-hidden.
// We don't necessarily want to keep searching in the case of any ignored
// node, because we anticipate that there might be scenarios where a
// descendant of the ignored node is not ignored and would be returned by
// the call to `GetFirstInlineBlockOrDeepestInlineAXChildInLayoutTree`
bool should_keep_looking =
result ? result->IsInert() || result->IsAriaHidden() : false;
result =
GetFirstInlineBlockOrDeepestInlineAXChildInLayoutTree(result, false);
if (result && !should_keep_looking) {
return SetPreviousOnLine(result);
}
// We want to continue searching for the previous inline leaf if the
// current one is inert.
if (!should_keep_looking) {
break;
}
previous_layout_object =
AXObjectCache().CachedPreviousOnLine(previous_layout_object);
}
return SetPreviousOnLine(nullptr);
}
void AXNodeObject::HandleAutofillSuggestionAvailabilityChanged(
WebAXAutofillSuggestionAvailability suggestion_availability) {
if (GetLayoutObject()) {
// Autofill suggestion availability is stored in AXObjectCache.
AXObjectCache().SetAutofillSuggestionAvailability(AXObjectID(),
suggestion_availability);
}
}
void AXNodeObject::GetWordBoundaries(Vector<int>& word_starts,
Vector<int>& word_ends) const {
if (!GetLayoutObject() || !GetLayoutObject()->IsListMarker()) {
return;
}
String text_alternative;
if (ListMarker* marker = ListMarker::Get(GetLayoutObject())) {
text_alternative = marker->TextAlternative(*GetLayoutObject());
}
if (text_alternative.ContainsOnlyWhitespaceOrEmpty()) {
return;
}
Vector<AbstractInlineTextBox::WordBoundaries> boundaries;
AbstractInlineTextBox::GetWordBoundariesForText(boundaries, text_alternative);
word_starts.reserve(boundaries.size());
word_ends.reserve(boundaries.size());
for (const auto& boundary : boundaries) {
word_starts.push_back(boundary.start_index);
word_ends.push_back(boundary.end_index);
}
}
void AXNodeObject::Trace(Visitor* visitor) const {
visitor->Trace(node_);
visitor->Trace(layout_object_);
visitor->Trace(generational_cache_);
AXObject::Trace(visitor);
}
} // namespace blink