blob: 3b6ddfe1e375b2c8cb4c342680010f56e89b328f [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/accessibility/browser_accessibility_manager_win.h"
#include <stddef.h>
#include <stdint.h>
#include <vector>
#include "base/command_line.h"
#include "base/win/windows_version.h"
#include "content/browser/accessibility/browser_accessibility_state_impl.h"
#include "content/browser/accessibility/browser_accessibility_win.h"
#include "content/browser/renderer_host/legacy_render_widget_host_win.h"
#include "content/common/accessibility_messages.h"
#include "ui/base/win/atl_module.h"
namespace content {
// static
BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
const ui::AXTreeUpdate& initial_tree,
BrowserAccessibilityDelegate* delegate,
BrowserAccessibilityFactory* factory) {
return new BrowserAccessibilityManagerWin(initial_tree, delegate, factory);
}
BrowserAccessibilityManagerWin*
BrowserAccessibilityManager::ToBrowserAccessibilityManagerWin() {
return static_cast<BrowserAccessibilityManagerWin*>(this);
}
BrowserAccessibilityManagerWin::BrowserAccessibilityManagerWin(
const ui::AXTreeUpdate& initial_tree,
BrowserAccessibilityDelegate* delegate,
BrowserAccessibilityFactory* factory)
: BrowserAccessibilityManager(delegate, factory),
load_complete_pending_(false) {
ui::win::CreateATLModuleIfNeeded();
Initialize(initial_tree);
}
BrowserAccessibilityManagerWin::~BrowserAccessibilityManagerWin() {
// Destroy the tree in the subclass, rather than in the inherited
// destructor, otherwise our overrides of functions like
// OnNodeWillBeDeleted won't be called.
tree_.reset(NULL);
}
// static
ui::AXTreeUpdate
BrowserAccessibilityManagerWin::GetEmptyDocument() {
ui::AXNodeData empty_document;
empty_document.id = 0;
empty_document.role = ax::mojom::Role::kRootWebArea;
empty_document.AddBoolAttribute(ax::mojom::BoolAttribute::kBusy, true);
ui::AXTreeUpdate update;
update.root_id = empty_document.id;
update.nodes.push_back(empty_document);
return update;
}
HWND BrowserAccessibilityManagerWin::GetParentHWND() {
BrowserAccessibilityDelegate* delegate = GetDelegateFromRootManager();
if (!delegate)
return NULL;
return delegate->AccessibilityGetAcceleratedWidget();
}
void BrowserAccessibilityManagerWin::UserIsReloading() {
if (GetRoot())
FireWinAccessibilityEvent(IA2_EVENT_DOCUMENT_RELOAD, GetRoot());
}
BrowserAccessibility* BrowserAccessibilityManagerWin::GetFocus() {
BrowserAccessibility* focus = BrowserAccessibilityManager::GetFocus();
return GetActiveDescendant(focus);
}
void BrowserAccessibilityManagerWin::FireFocusEvent(
BrowserAccessibility* node) {
BrowserAccessibilityManager::FireFocusEvent(node);
DCHECK(node);
FireWinAccessibilityEvent(EVENT_OBJECT_FOCUS, node);
}
void BrowserAccessibilityManagerWin::FireBlinkEvent(
ax::mojom::Event event_type,
BrowserAccessibility* node) {
BrowserAccessibilityManager::FireBlinkEvent(event_type, node);
switch (event_type) {
case ax::mojom::Event::kLocationChanged:
FireWinAccessibilityEvent(IA2_EVENT_VISIBLE_DATA_CHANGED, node);
break;
case ax::mojom::Event::kScrolledToAnchor:
FireWinAccessibilityEvent(EVENT_SYSTEM_SCROLLINGSTART, node);
break;
default:
break;
}
}
void BrowserAccessibilityManagerWin::FireGeneratedEvent(
ui::AXEventGenerator::Event event_type,
BrowserAccessibility* node) {
BrowserAccessibilityManager::FireGeneratedEvent(event_type, node);
bool can_fire_events = CanFireEvents();
if (event_type == ui::AXEventGenerator::Event::LOAD_COMPLETE &&
can_fire_events)
load_complete_pending_ = false;
if (load_complete_pending_ && can_fire_events && GetRoot()) {
load_complete_pending_ = false;
FireWinAccessibilityEvent(IA2_EVENT_DOCUMENT_LOAD_COMPLETE, GetRoot());
}
if (!can_fire_events && !load_complete_pending_ &&
event_type == ui::AXEventGenerator::Event::LOAD_COMPLETE && GetRoot() &&
!GetRoot()->IsOffscreen() && GetRoot()->PlatformChildCount() > 0) {
load_complete_pending_ = true;
}
switch (event_type) {
case ui::AXEventGenerator::Event::ACTIVE_DESCENDANT_CHANGED:
FireWinAccessibilityEvent(IA2_EVENT_ACTIVE_DESCENDANT_CHANGED, node);
break;
case ui::AXEventGenerator::Event::ALERT:
FireWinAccessibilityEvent(EVENT_SYSTEM_ALERT, node);
break;
case ui::AXEventGenerator::Event::CHILDREN_CHANGED:
FireWinAccessibilityEvent(EVENT_OBJECT_REORDER, node);
break;
case ui::AXEventGenerator::Event::LIVE_REGION_CHANGED:
// This event is redundant with the IA2_EVENT_TEXT_INSERTED events;
// however, JAWS 2018 and earlier do not process the text inserted
// events when "virtual cursor mode" is turned off (Insert+Z).
// Fortunately, firing the redudant event does not cause duplicate
// verbalizations in either screen reader.
// Future versions of JAWS may process the text inserted event when
// in focus mode, and so at some point the live region
// changed events may truly become redundant with the text inserted
// events. Note: Firefox does not fire this event, but JAWS processes
// Firefox live region events differently (utilizes MSAA's
// EVENT_OBJECT_SHOW).
FireWinAccessibilityEvent(EVENT_OBJECT_LIVEREGIONCHANGED, node);
break;
case ui::AXEventGenerator::Event::LOAD_COMPLETE:
FireWinAccessibilityEvent(IA2_EVENT_DOCUMENT_LOAD_COMPLETE, node);
break;
case ui::AXEventGenerator::Event::SCROLL_POSITION_CHANGED:
FireWinAccessibilityEvent(EVENT_SYSTEM_SCROLLINGEND, node);
break;
case ui::AXEventGenerator::Event::SELECTED_CHILDREN_CHANGED:
FireWinAccessibilityEvent(EVENT_OBJECT_SELECTIONWITHIN, node);
break;
case ui::AXEventGenerator::Event::DOCUMENT_SELECTION_CHANGED: {
// Fire the event on the object where the focus of the selection is.
int32_t focus_id = GetTreeData().sel_focus_object_id;
BrowserAccessibility* focus_object = GetFromID(focus_id);
if (focus_object && focus_object->HasVisibleCaretOrSelection())
FireWinAccessibilityEvent(IA2_EVENT_TEXT_CARET_MOVED, focus_object);
break;
}
case ui::AXEventGenerator::Event::CHECKED_STATE_CHANGED:
case ui::AXEventGenerator::Event::COLLAPSED:
case ui::AXEventGenerator::Event::DESCRIPTION_CHANGED:
case ui::AXEventGenerator::Event::DOCUMENT_TITLE_CHANGED:
case ui::AXEventGenerator::Event::EXPANDED:
case ui::AXEventGenerator::Event::INVALID_STATUS_CHANGED:
case ui::AXEventGenerator::Event::LIVE_REGION_CREATED:
case ui::AXEventGenerator::Event::LIVE_REGION_NODE_CHANGED:
case ui::AXEventGenerator::Event::LOAD_START:
case ui::AXEventGenerator::Event::MENU_ITEM_SELECTED:
case ui::AXEventGenerator::Event::NAME_CHANGED:
case ui::AXEventGenerator::Event::OTHER_ATTRIBUTE_CHANGED:
case ui::AXEventGenerator::Event::RELATED_NODE_CHANGED:
case ui::AXEventGenerator::Event::ROLE_CHANGED:
case ui::AXEventGenerator::Event::ROW_COUNT_CHANGED:
case ui::AXEventGenerator::Event::SELECTED_CHANGED:
case ui::AXEventGenerator::Event::STATE_CHANGED:
case ui::AXEventGenerator::Event::VALUE_CHANGED:
// There are some notifications that aren't meaningful on Windows.
// It's okay to skip them.
break;
}
}
void BrowserAccessibilityManagerWin::FireWinAccessibilityEvent(
LONG win_event_type,
BrowserAccessibility* node) {
if (!node->CanFireEvents())
return;
// If there's no root delegate, this may be a new frame that hasn't
// yet been swapped in or added to the frame tree. Suppress firing events
// until then.
BrowserAccessibilityDelegate* root_delegate = GetDelegateFromRootManager();
if (!root_delegate)
return;
HWND hwnd = root_delegate->AccessibilityGetAcceleratedWidget();
if (!hwnd)
return;
// Don't fire events when this document might be stale as the user has
// started navigating to a new document.
if (user_is_navigating_away_)
return;
// Inline text boxes are an internal implementation detail, we don't
// expose them to Windows.
if (node->GetRole() == ax::mojom::Role::kInlineTextBox)
return;
// Pass the negation of this node's unique id in the |child_id|
// argument to NotifyWinEvent; the AT client will then call get_accChild
// on the HWND's accessibility object and pass it that same id, which
// we can use to retrieve the IAccessible for this node.
LONG child_id = -(ToBrowserAccessibilityWin(node)->GetCOM()->GetUniqueId());
::NotifyWinEvent(win_event_type, hwnd, OBJID_CLIENT, child_id);
}
bool BrowserAccessibilityManagerWin::CanFireEvents() {
BrowserAccessibilityDelegate* root_delegate = GetDelegateFromRootManager();
if (!root_delegate)
return false;
HWND hwnd = root_delegate->AccessibilityGetAcceleratedWidget();
return hwnd != nullptr;
}
gfx::Rect BrowserAccessibilityManagerWin::GetViewBounds() {
// We have to take the device scale factor into account on Windows.
BrowserAccessibilityDelegate* delegate = GetDelegateFromRootManager();
if (delegate) {
gfx::Rect bounds = delegate->AccessibilityGetViewBounds();
if (device_scale_factor() > 0.0 && device_scale_factor() != 1.0)
bounds = ScaleToEnclosingRect(bounds, device_scale_factor());
return bounds;
}
return gfx::Rect();
}
void BrowserAccessibilityManagerWin::OnAtomicUpdateFinished(
ui::AXTree* tree,
bool root_changed,
const std::vector<ui::AXTreeObserver::Change>& changes) {
BrowserAccessibilityManager::OnAtomicUpdateFinished(
tree, root_changed, changes);
// Do a sequence of Windows-specific updates on each node. Each one is
// done in a single pass that must complete before the next step starts.
// The first step moves win_attributes_ to old_win_attributes_ and then
// recomputes all of win_attributes_ other than IAccessibleText.
for (const auto& change : changes) {
const ui::AXNode* changed_node = change.node;
DCHECK(changed_node);
BrowserAccessibility* obj = GetFromAXNode(changed_node);
if (obj && obj->IsNative()) {
ToBrowserAccessibilityWin(obj)
->GetCOM()
->UpdateStep1ComputeWinAttributes();
}
}
// The next step updates the hypertext of each node, which is a
// concatenation of all of its child text nodes, so it can't run until
// the text of all of the nodes was computed in the previous step.
for (const auto& change : changes) {
const ui::AXNode* changed_node = change.node;
DCHECK(changed_node);
BrowserAccessibility* obj = GetFromAXNode(changed_node);
if (obj && obj->IsNative())
ToBrowserAccessibilityWin(obj)->GetCOM()->UpdateStep2ComputeHypertext();
}
// The third step fires events on nodes based on what's changed - like
// if the name, value, or description changed, or if the hypertext had
// text inserted or removed. It's able to figure out exactly what changed
// because we still have old_win_attributes_ populated.
// This step has to run after the previous two steps complete because the
// client may walk the tree when it receives any of these events.
// At the end, it deletes old_win_attributes_ since they're not needed
// anymore.
for (const auto& change : changes) {
const ui::AXNode* changed_node = change.node;
DCHECK(changed_node);
BrowserAccessibility* obj = GetFromAXNode(changed_node);
if (obj && obj->IsNative()) {
ToBrowserAccessibilityWin(obj)->GetCOM()->UpdateStep3FireEvents(
change.type == AXTreeObserver::SUBTREE_CREATED);
}
}
}
} // namespace content