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 "HyperTextAccessible.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 focus the host
  49  * accessible programmatically.
  50  */
  51 class LinkableAccessible : public AccessibleWrap {
  52  public:
  53   LinkableAccessible(nsIContent* aContent, DocAccessible* aDoc)
  54       : AccessibleWrap(aContent, aDoc) {}
  55
  56   NS_INLINE_DECL_REFCOUNTING_INHERITED(LinkableAccessible, AccessibleWrap)
  57
  58   // LocalAccessible
  59   virtual void Value(nsString& aValue) const override;
  60   virtual uint64_t NativeLinkState() const override;
  61   virtual void TakeFocus() const override;
  62
  63   // ActionAccessible
  64   virtual KeyBinding AccessKey() const override;
  65
  66   // ActionAccessible helpers
  67   const LocalAccessible* ActionWalk(bool* aIsLink = nullptr,
  68                                     bool* aIsOnclick = nullptr) const;
  69
  70  protected:
  71   virtual ~LinkableAccessible() {}
  72 };
  73
  74 /**
  75  * A simple accessible that gets its enumerated role.
  76  */
  77 template <a11y::role R>
  78 class EnumRoleAccessible : public AccessibleWrap {
  79  public:
  80   EnumRoleAccessible(nsIContent* aContent, DocAccessible* aDoc)
  81       : AccessibleWrap(aContent, aDoc) {}
  82
  83   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aPtr) override {
  84     return LocalAccessible::QueryInterface(aIID, aPtr);
  85   }
  86
  87   // LocalAccessible
  88   virtual a11y::role NativeRole() const override { return R; }
  89
  90  protected:
  91   virtual ~EnumRoleAccessible() {}
  92 };
  93
  94 /**
  95  * Like EnumRoleAccessible, but with text support.
  96  */
  97 template <a11y::role R>
  98 class EnumRoleHyperTextAccessible : public HyperTextAccessible {
  99  public:
 100   EnumRoleHyperTextAccessible(nsIContent* aContent, DocAccessible* aDoc)
 101       : HyperTextAccessible(aContent, aDoc) {}
 102
 103   // LocalAccessible
 104   virtual a11y::role NativeRole() const override { return R; }
 105
 106  protected:
 107   virtual ~EnumRoleHyperTextAccessible() {}
 108 };
 109
 110 /**
 111  * A wrapper accessible around native accessible to connect it with
 112  * crossplatform accessible tree.
 113  */
 114 class DummyAccessible : public AccessibleWrap {
 115  public:
 116   explicit DummyAccessible(DocAccessible* aDocument = nullptr)
 117       : AccessibleWrap(nullptr, aDocument) {
 118     // IsDefunct() asserts if mContent is null, which is always true for
 119     // DummyAccessible. We can prevent this by setting eSharedNode.
 120     mStateFlags |= eSharedNode;
 121   }
 122
 123   uint64_t NativeState() const final;
 124   uint64_t NativeInteractiveState() const final;
 125   uint64_t NativeLinkState() const final;
 126   bool NativelyUnavailable() const final;
 127   void ApplyARIAState(uint64_t* aState) const final;
 128
 129  protected:
 130   virtual ~DummyAccessible() {}
 131 };
 132
 133 }  // namespace a11y
 134 }  // namespace mozilla
 135
 136 #endif