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// Copyright 2018 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.
#ifndef UI_VIEWS_ACCESSIBILITY_AX_VIRTUAL_VIEW_H_
#define UI_VIEWS_ACCESSIBILITY_AX_VIRTUAL_VIEW_H_
#include <stdint.h>
#include <memory>
#include <vector>
#include "base/callback_forward.h"
#include "base/strings/string16.h"
#include "ui/accessibility/ax_enums.mojom-forward.h"
#include "ui/accessibility/ax_node_data.h"
#include "ui/accessibility/platform/ax_platform_node_delegate_base.h"
#include "ui/accessibility/platform/ax_unique_id.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/native_widget_types.h"
#include "ui/views/views_export.h"
#if defined(USE_AURA)
#include "ui/views/accessibility/ax_virtual_view_wrapper.h"
#else
// Currently unused.
class AXVirtualViewWrapper {};
#endif
namespace ui {
struct AXActionData;
class AXUniqueId;
} // namespace ui
namespace views {
class AXAuraObjCache;
class View;
class ViewAccessibility;
class ViewAXPlatformNodeDelegate;
// Implements a virtual view that is used only for accessibility.
//
// Some composite widgets such as tree and table views may utilize lightweight
// UI objects instead of actual views for displaying and managing their
// contents. We need a corresponding virtual accessibility view to expose
// information about these lightweight Ui objects to accessibility. An
// AXVirtualView is owned by its parent, which could either be a
// ViewAccessibility or an AXVirtualView.
class VIEWS_EXPORT AXVirtualView : public ui::AXPlatformNodeDelegateBase {
public:
using AXVirtualViews = std::vector<std::unique_ptr<AXVirtualView>>;
static AXVirtualView* GetFromId(int32_t id);
AXVirtualView();
AXVirtualView(const AXVirtualView&) = delete;
AXVirtualView& operator=(const AXVirtualView&) = delete;
~AXVirtualView() override;
//
// Methods for managing parent - child relationships.
//
// Adds |view| as a child of this virtual view, optionally at |index|.
// We take ownership of our children.
void AddChildView(std::unique_ptr<AXVirtualView> view);
void AddChildViewAt(std::unique_ptr<AXVirtualView> view, int index);
// Moves |view| to the specified |index|. A negative value for |index| moves
// |view| to the end.
void ReorderChildView(AXVirtualView* view, int index);
// Removes this virtual view from its parent, which could either be a virtual
// or a real view. Hands ownership of this view back to the caller.
std::unique_ptr<AXVirtualView> RemoveFromParentView();
// Removes |view| from this virtual view. The view's parent will change to
// nullptr. Hands ownership back to the caller.
std::unique_ptr<AXVirtualView> RemoveChildView(AXVirtualView* view);
// Removes all the children from this virtual view.
// The virtual views are deleted.
void RemoveAllChildViews();
const AXVirtualViews& children() const { return children_; }
// Returns the parent ViewAccessibility if the parent is a real View and not
// an AXVirtualView. Returns nullptr otherwise.
const ViewAccessibility* parent_view() const { return parent_view_; }
ViewAccessibility* parent_view() { return parent_view_; }
// Returns the parent view if the parent is an AXVirtualView and not a real
// View. Returns nullptr otherwise.
const AXVirtualView* virtual_parent_view() const {
return virtual_parent_view_;
}
AXVirtualView* virtual_parent_view() { return virtual_parent_view_; }
ui::AXPlatformNode* ax_platform_node() { return ax_platform_node_; }
// Returns true if |view| is contained within the hierarchy of this
// AXVirtualView, even as an indirect descendant. Will return true if |view|
// is also this AXVirtualView.
bool Contains(const AXVirtualView* view) const;
// Returns the index of |view|, or -1 if |view| is not a child of this virtual
// view.
int GetIndexOf(const AXVirtualView* view) const;
//
// Other methods.
//
const char* GetViewClassName() const;
gfx::NativeViewAccessible GetNativeObject() const;
void NotifyAccessibilityEvent(ax::mojom::Event event_type);
// Allows clients to modify the AXNodeData for this virtual view. This should
// be used for attributes that are relatively stable and do not change
// dynamically.
ui::AXNodeData& GetCustomData();
// Allows clients to modify the AXNodeData for this virtual view dynamically
// via a callback. This should be used for attributes that change often and
// would be queried every time a client accesses this view's AXNodeData.
void SetPopulateDataCallback(
base::RepeatingCallback<void(ui::AXNodeData*)> callback);
void UnsetPopulateDataCallback();
// ui::AXPlatformNodeDelegate. Note that
// - Some of these functions have Mac-specific implementations in
// ax_virtual_view_mac.mm.
// - GetChildCount(), ChildAtIndex(), and GetParent() are used by assistive
// technologies to access the unignored accessibility tree, which doesn't
// necessarily reflect the internal descendant tree. (An ignored node means
// that the node should not be exposed to the platform.)
const ui::AXNodeData& GetData() const override;
int GetChildCount() const override;
gfx::NativeViewAccessible ChildAtIndex(int index) override;
gfx::NativeViewAccessible GetNSWindow() override;
gfx::NativeViewAccessible GetNativeViewAccessible() override;
gfx::NativeViewAccessible GetParent() override;
gfx::Rect GetBoundsRect(
const ui::AXCoordinateSystem coordinate_system,
const ui::AXClippingBehavior clipping_behavior,
ui::AXOffscreenResult* offscreen_result = nullptr) const override;
gfx::NativeViewAccessible HitTestSync(
int screen_physical_pixel_x,
int screen_physical_pixel_y) const override;
gfx::NativeViewAccessible GetFocus() const override;
ui::AXPlatformNode* GetFromNodeID(int32_t id) override;
bool AccessibilityPerformAction(const ui::AXActionData& data) override;
bool ShouldIgnoreHoveredStateForTesting() override;
bool IsOffscreen() const override;
const ui::AXUniqueId& GetUniqueId() const override;
gfx::AcceleratedWidget GetTargetForNativeAccessibilityEvent() override;
base::Optional<bool> GetTableHasColumnOrRowHeaderNode() const override;
std::vector<int32_t> GetColHeaderNodeIds() const override;
std::vector<int32_t> GetColHeaderNodeIds(int col_index) const override;
// Gets the real View that owns our shallowest virtual ancestor,, if any.
View* GetOwnerView() const;
// Gets the view platform delegate if exists, otherwise nullptr.
ViewAXPlatformNodeDelegate* GetDelegate() const;
// Gets or creates a wrapper suitable for use with tree sources.
AXVirtualViewWrapper* GetOrCreateWrapper(views::AXAuraObjCache* cache);
// Returns true if this node is ignored and should be hidden from the
// accessibility tree. This does not impact the node's descendants.
bool IsIgnored() const;
// Handle a request from assistive technology to perform an action on this
// virtual view. Returns true on success, but note that the success/failure is
// not propagated to the client that requested the action, since the
// request is sometimes asynchronous. The right way to send a response is
// via NotifyAccessibilityEvent().
virtual bool HandleAccessibleAction(const ui::AXActionData& action_data);
protected:
// Forwards a request from assistive technology to perform an action on this
// virtual view to the owner view's accessible action handler.
bool HandleAccessibleActionInOwnerView(const ui::AXActionData& action_data);
private:
// Internal class name.
static const char kViewClassName[];
// Sets the parent ViewAccessibility if the parent is a real View and not an
// AXVirtualView. It is invalid to set both |parent_view_| and
// |virtual_parent_view_|.
void set_parent_view(ViewAccessibility* view_accessibility) {
DCHECK(!virtual_parent_view_);
parent_view_ = view_accessibility;
}
// We own this, but it is reference-counted on some platforms so we can't use
// a unique_ptr. It is destroyed in the destructor.
ui::AXPlatformNode* ax_platform_node_;
// Weak. Owns us if not nullptr.
// Either |parent_view_| or |virtual_parent_view_| should be set but not both.
ViewAccessibility* parent_view_ = nullptr;
// Weak. Owns us if not nullptr.
// Either |parent_view_| or |virtual_parent_view_| should be set but not both.
AXVirtualView* virtual_parent_view_ = nullptr;
// We own our children.
AXVirtualViews children_;
ui::AXUniqueId unique_id_;
ui::AXNodeData custom_data_;
base::RepeatingCallback<void(ui::AXNodeData*)> populate_data_callback_;
std::unique_ptr<AXVirtualViewWrapper> wrapper_;
friend class ViewAccessibility;
};
} // namespace views
#endif // UI_VIEWS_ACCESSIBILITY_AX_VIRTUAL_VIEW_H_