ui/accessibility/platform/ax_platform_node.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_H_
   6 #define UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_H_
   7
   8 #include "ui/accessibility/ax_enums.h"
   9 #include "ui/accessibility/ax_export.h"
  10 #include "ui/gfx/native_widget_types.h"
  11
  12 namespace ui {
  13
  14 class AXPlatformNodeDelegate;
  15
  16 // AXPlatformNode is the abstract base class for an implementation of
  17 // native accessibility APIs on supported platforms (e.g. Windows, Mac OS X).
  18 // An object that wants to be accessible can derive from AXPlatformNodeDelegate
  19 // and then call AXPlatformNode::Create. The delegate implementation should
  20 // own the AXPlatformNode instance (or otherwise manage its lifecycle).
  21 class AX_EXPORT AXPlatformNode {
  22  public:
  23   // Create an appropriate platform-specific instance. The delegate owns the
  24   // AXPlatformNode instance (or manages its lifecycle in some other way).
  25   static AXPlatformNode* Create(AXPlatformNodeDelegate* delegate);
  26
  27   // Cast a gfx::NativeViewAccessible to an AXPlatformNode if it is one,
  28   // or return NULL if it's not an instance of this class.
  29   static AXPlatformNode* FromNativeViewAccessible(
  30       gfx::NativeViewAccessible accessible);
  31
  32   // Call Destroy rather than deleting this, because the subclass may
  33   // use reference counting.
  34   virtual void Destroy() = 0;
  35
  36   // Get the platform-specific accessible object type for this instance.
  37   // On some platforms this is just a type cast, on others it may be a
  38   // wrapper object or handle.
  39   virtual gfx::NativeViewAccessible GetNativeViewAccessible() = 0;
  40
  41   // Fire a platform-specific notification that an event has occurred on
  42   // this object.
  43   virtual void NotifyAccessibilityEvent(ui::AXEvent event_type) = 0;
  44
  45   // Return this object's delegate.
  46   virtual AXPlatformNodeDelegate* GetDelegate() const = 0;
  47
  48  protected:
  49   AXPlatformNode();
  50   virtual ~AXPlatformNode();
  51 };
  52
  53 }  // namespace ui
  54
  55 #endif  // UI_ACCESSIBILITY_PLATFORM_AX_PLATFORM_NODE_H_