gecko-dev/accessible/base/TreeWalker.h

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2.3 KiB
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/* -*- 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_TreeWalker_h_
#define mozilla_a11y_TreeWalker_h_
#include "mozilla/Attributes.h"
#include <stdint.h>
#include "mozilla/dom/ChildIterator.h"
#include "nsCOMPtr.h"
class nsIContent;
namespace mozilla {
namespace a11y {
class Accessible;
class DocAccessible;
/**
* This class is used to walk the DOM tree to create accessible tree.
*/
class TreeWalker MOZ_FINAL
{
public:
enum {
// used to walk the existing tree of the given node
eWalkCache = 1,
// used to walk the context tree starting from given node
eWalkContextTree = 2 | eWalkCache
};
/**
* Constructor
*
* @param aContext [in] container accessible for the given node, used to
* define accessible context
* @param aNode [in] the node the search will be prepared relative to
* @param aFlags [in] flags (see enum above)
*/
TreeWalker(Accessible* aContext, nsIContent* aNode, uint32_t aFlags = 0);
~TreeWalker();
/**
* Return the next child accessible.
*
* @note Returned accessible is bound to the document, if the accessible is
* rejected during tree creation then the caller should be unbind it
* from the document.
*/
Accessible* NextChild();
private:
TreeWalker();
TreeWalker(const TreeWalker&);
TreeWalker& operator =(const TreeWalker&);
/**
* Create new state for the given node and push it on top of stack.
*
* @note State stack is used to navigate up/down the DOM subtree during
* accessible children search.
*/
dom::AllChildrenIterator* PushState(nsIContent* aContent)
{
return mStateStack.AppendElement(dom::AllChildrenIterator(aContent,
mChildFilter));
}
/**
* Pop state from stack.
*/
dom::AllChildrenIterator* PopState();
DocAccessible* mDoc;
Accessible* mContext;
nsIContent* mAnchorNode;
nsAutoTArray<dom::AllChildrenIterator, 20> mStateStack;
int32_t mChildFilter;
uint32_t mFlags;
};
} // namespace a11y
} // namespace mozilla
#endif // mozilla_a11y_TreeWalker_h_