gecko-dev/accessible/generic/BaseAccessibles.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_a11y_BaseAccessibles_h__
#define mozilla_a11y_BaseAccessibles_h__

#include "AccessibleWrap.h"
#include "HyperTextAccessible.h"

class nsIContent;

/**
 * This file contains a number of classes that are used as base
 *  classes for the different accessibility implementations of
 *  the HTML and XUL widget sets.  --jgaunt
 */

namespace mozilla {
namespace a11y {

/**
 * Leaf version of DOM Accessible -- has no children
 */
class LeafAccessible : public AccessibleWrap {
 public:
  LeafAccessible(nsIContent* aContent, DocAccessible* aDoc);

  // nsISupports
  NS_INLINE_DECL_REFCOUNTING_INHERITED(LeafAccessible, AccessibleWrap)

  // LocalAccessible
  virtual LocalAccessible* LocalChildAtPoint(
      int32_t aX, int32_t aY, EWhichChildAtPoint aWhichChild) override;
  bool InsertChildAt(uint32_t aIndex, LocalAccessible* aChild) final;
  bool RemoveChild(LocalAccessible* aChild) final;

  virtual bool IsAcceptableChild(nsIContent* aEl) const override;

 protected:
  virtual ~LeafAccessible() {}
};

/**
 * Used for text or image accessible nodes contained by link accessibles or
 * accessibles for nodes with registered click event handler. It knows how to
 * report the state of the host link (traveled or not) and can focus the host
 * accessible programmatically.
 */
class LinkableAccessible : public AccessibleWrap {
 public:
  LinkableAccessible(nsIContent* aContent, DocAccessible* aDoc)
      : AccessibleWrap(aContent, aDoc) {}

  NS_INLINE_DECL_REFCOUNTING_INHERITED(LinkableAccessible, AccessibleWrap)

  // LocalAccessible
  virtual void Value(nsString& aValue) const override;
  virtual uint64_t NativeLinkState() const override;
  virtual void TakeFocus() const override;

  // ActionAccessible
  virtual KeyBinding AccessKey() const override;

  // ActionAccessible helpers
  const LocalAccessible* ActionWalk(bool* aIsLink = nullptr,
                                    bool* aIsOnclick = nullptr) const;

 protected:
  virtual ~LinkableAccessible() {}
};

/**
 * A simple accessible that gets its enumerated role.
 */
template <a11y::role R>
class EnumRoleAccessible : public AccessibleWrap {
 public:
  EnumRoleAccessible(nsIContent* aContent, DocAccessible* aDoc)
      : AccessibleWrap(aContent, aDoc) {}

  NS_IMETHOD QueryInterface(REFNSIID aIID, void** aPtr) override {
    return LocalAccessible::QueryInterface(aIID, aPtr);
  }

  // LocalAccessible
  virtual a11y::role NativeRole() const override { return R; }

 protected:
  virtual ~EnumRoleAccessible() {}
};

/**
 * Like EnumRoleAccessible, but with text support.
 */
template <a11y::role R>
class EnumRoleHyperTextAccessible : public HyperTextAccessible {
 public:
  EnumRoleHyperTextAccessible(nsIContent* aContent, DocAccessible* aDoc)
      : HyperTextAccessible(aContent, aDoc) {}

  // LocalAccessible
  virtual a11y::role NativeRole() const override { return R; }

 protected:
  virtual ~EnumRoleHyperTextAccessible() {}
};

/**
 * A wrapper accessible around native accessible to connect it with
 * crossplatform accessible tree.
 */
class DummyAccessible : public AccessibleWrap {
 public:
  explicit DummyAccessible(DocAccessible* aDocument = nullptr)
      : AccessibleWrap(nullptr, aDocument) {
    // IsDefunct() asserts if mContent is null, which is always true for
    // DummyAccessible. We can prevent this by setting eSharedNode.
    mStateFlags |= eSharedNode;
  }

  uint64_t NativeState() const final;
  uint64_t NativeInteractiveState() const final;
  uint64_t NativeLinkState() const final;
  bool NativelyUnavailable() const final;
  void ApplyARIAState(uint64_t* aState) const final;

 protected:
  virtual ~DummyAccessible() {}
};

}  // namespace a11y
}  // namespace mozilla

#endif