145 lines
3.7 KiB
C++
145 lines
3.7 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_a11y_TreeWalker_h_
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#define mozilla_a11y_TreeWalker_h_
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#include "mozilla/Attributes.h"
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#include <stdint.h>
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#include "mozilla/dom/ChildIterator.h"
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#include "nsCOMPtr.h"
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class nsIContent;
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namespace mozilla {
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namespace a11y {
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class Accessible;
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class DocAccessible;
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/**
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* This class is used to walk the DOM tree to create accessible tree.
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*/
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class TreeWalker final
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{
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public:
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enum {
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// used to walk the existing tree of the given node
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eWalkCache = 1,
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// used to walk the context tree starting from given node
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eWalkContextTree = 2 | eWalkCache
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};
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/**
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* Used to navigate and create if needed the accessible children.
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*/
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explicit TreeWalker(Accessible* aContext);
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/**
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* Used to navigate the accessible children relative to the anchor.
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*
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* @param aContext [in] container accessible for the given node, used to
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* define accessible context
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* @param aAnchorNode [in] the node the search will be prepared relative to
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* @param aFlags [in] flags (see enum above)
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*/
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TreeWalker(Accessible* aContext, nsIContent* aAnchorNode, uint32_t aFlags = eWalkCache);
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~TreeWalker();
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/**
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* Resets the walker state, and sets the given node as an anchor. Returns a
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* first accessible element within the node including the node itself.
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*/
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Accessible* Scope(nsIContent* aAnchorNode);
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/**
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* Resets the walker state.
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*/
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void Reset()
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{
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mPhase = eAtStart;
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mStateStack.Clear();
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mARIAOwnsIdx = 0;
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}
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/**
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* Sets the walker state to the given child node if it's within the anchor.
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*/
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bool Seek(nsIContent* aChildNode);
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/**
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* Return the next/prev accessible.
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*
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* @note Returned accessible is bound to the document, if the accessible is
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* rejected during tree creation then the caller should be unbind it
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* from the document.
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*/
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Accessible* Next();
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Accessible* Prev();
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Accessible* Context() const { return mContext; }
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DocAccessible* Document() const { return mDoc; }
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private:
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TreeWalker();
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TreeWalker(const TreeWalker&);
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TreeWalker& operator =(const TreeWalker&);
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/**
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* Return an accessible for the given node if any.
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*/
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Accessible* AccessibleFor(nsIContent* aNode, uint32_t aFlags,
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bool* aSkipSubtree);
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/**
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* Create new state for the given node and push it on top of stack / at bottom
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* of stack.
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*
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* @note State stack is used to navigate up/down the DOM subtree during
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* accessible children search.
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*/
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dom::AllChildrenIterator* PushState(nsIContent* aContent,
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bool aStartAtBeginning)
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{
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return mStateStack.AppendElement(
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dom::AllChildrenIterator(aContent, mChildFilter, aStartAtBeginning));
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}
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dom::AllChildrenIterator* PrependState(nsIContent* aContent,
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bool aStartAtBeginning)
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{
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return mStateStack.InsertElementAt(0,
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dom::AllChildrenIterator(aContent, mChildFilter, aStartAtBeginning));
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}
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/**
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* Pop state from stack.
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*/
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dom::AllChildrenIterator* PopState();
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DocAccessible* mDoc;
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Accessible* mContext;
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nsIContent* mAnchorNode;
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AutoTArray<dom::AllChildrenIterator, 20> mStateStack;
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uint32_t mARIAOwnsIdx;
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int32_t mChildFilter;
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uint32_t mFlags;
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enum Phase {
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eAtStart,
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eAtDOM,
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eAtARIAOwns,
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eAtEnd
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};
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Phase mPhase;
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};
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} // namespace a11y
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} // namespace mozilla
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#endif // mozilla_a11y_TreeWalker_h_
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