accessible/generic/BaseAccessibles.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef mozilla_a11y_BaseAccessibles_h__
   7 #define mozilla_a11y_BaseAccessibles_h__
   8
   9 #include "AccessibleWrap.h"
  10 #include "HyperTextAccessibleWrap.h"
  11
  12 class nsIContent;
  13
  14 /**
  15  * This file contains a number of classes that are used as base
  16  *  classes for the different accessibility implementations of
  17  *  the HTML and XUL widget sets.  --jgaunt
  18  */
  19
  20 namespace mozilla {
  21 namespace a11y {
  22
  23 /**
  24  * Leaf version of DOM Accessible -- has no children
  25  */
  26 class LeafAccessible : public AccessibleWrap {
  27  public:
  28   LeafAccessible(nsIContent* aContent, DocAccessible* aDoc);
  29
  30   // nsISupports
  31   NS_INLINE_DECL_REFCOUNTING_INHERITED(LeafAccessible, AccessibleWrap)
  32
  33   // LocalAccessible
  34   virtual LocalAccessible* LocalChildAtPoint(
  35       int32_t aX, int32_t aY, EWhichChildAtPoint aWhichChild) override;
  36   bool InsertChildAt(uint32_t aIndex, LocalAccessible* aChild) final;
  37   bool RemoveChild(LocalAccessible* aChild) final;
  38
  39   virtual bool IsAcceptableChild(nsIContent* aEl) const override;
  40
  41  protected:
  42   virtual ~LeafAccessible() {}
  43 };
  44
  45 /**
  46  * Used for text or image accessible nodes contained by link accessibles or
  47  * accessibles for nodes with registered click event handler. It knows how to
  48  * report the state of the host link (traveled or not) and can activate (click)
  49  * the host accessible programmatically.
  50  */
  51 class LinkableAccessible : public AccessibleWrap {
  52  public:
  53   enum { eAction_Jump = 0 };
  54
  55   LinkableAccessible(nsIContent* aContent, DocAccessible* aDoc)
  56       : AccessibleWrap(aContent, aDoc) {}
  57
  58   NS_INLINE_DECL_REFCOUNTING_INHERITED(LinkableAccessible, AccessibleWrap)
  59
  60   // LocalAccessible
  61   virtual void Value(nsString& aValue) const override;
  62   virtual uint64_t NativeLinkState() const override;
  63   virtual void TakeFocus() const override;
  64
  65   // ActionAccessible
  66   virtual uint8_t ActionCount() const override;
  67   virtual void ActionNameAt(uint8_t aIndex, nsAString& aName) override;
  68   virtual bool DoAction(uint8_t index) const override;
  69   virtual KeyBinding AccessKey() const override;
  70
  71   // ActionAccessible helpers
  72   const LocalAccessible* ActionWalk(bool* aIsLink = nullptr,
  73                                     bool* aIsOnclick = nullptr,
  74                                     bool* aIsLabelWithControl = nullptr) const;
  75   // HyperLinkAccessible
  76   virtual already_AddRefed<nsIURI> AnchorURIAt(
  77       uint32_t aAnchorIndex) const override;
  78
  79  protected:
  80   virtual ~LinkableAccessible() {}
  81 };
  82
  83 /**
  84  * A simple accessible that gets its enumerated role.
  85  */
  86 template <a11y::role R>
  87 class EnumRoleAccessible : public AccessibleWrap {
  88  public:
  89   EnumRoleAccessible(nsIContent* aContent, DocAccessible* aDoc)
  90       : AccessibleWrap(aContent, aDoc) {}
  91
  92   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aPtr) override {
  93     return LocalAccessible::QueryInterface(aIID, aPtr);
  94   }
  95
  96   // LocalAccessible
  97   virtual a11y::role NativeRole() const override { return R; }
  98
  99  protected:
 100   virtual ~EnumRoleAccessible() {}
 101 };
 102
 103 /**
 104  * A wrapper accessible around native accessible to connect it with
 105  * crossplatform accessible tree.
 106  */
 107 class DummyAccessible : public AccessibleWrap {
 108  public:
 109   explicit DummyAccessible(DocAccessible* aDocument = nullptr)
 110       : AccessibleWrap(nullptr, aDocument) {
 111     // IsDefunct() asserts if mContent is null, which is always true for
 112     // DummyAccessible. We can prevent this by setting eSharedNode.
 113     mStateFlags |= eSharedNode;
 114   }
 115
 116   uint64_t NativeState() const final;
 117   uint64_t NativeInteractiveState() const final;
 118   uint64_t NativeLinkState() const final;
 119   bool NativelyUnavailable() const final;
 120   void ApplyARIAState(uint64_t* aState) const final;
 121
 122  protected:
 123   virtual ~DummyAccessible() {}
 124 };
 125
 126 }  // namespace a11y
 127 }  // namespace mozilla
 128
 129 #endif