147 lines
4.1 KiB
C++
147 lines
4.1 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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#include "TreeWalker.h"
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#include "Accessible.h"
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#include "AccIterator.h"
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#include "nsAccessibilityService.h"
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#include "DocAccessible.h"
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#include "mozilla/dom/ChildIterator.h"
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#include "mozilla/dom/Element.h"
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using namespace mozilla;
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using namespace mozilla::a11y;
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////////////////////////////////////////////////////////////////////////////////
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// TreeWalker
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////////////////////////////////////////////////////////////////////////////////
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TreeWalker::
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TreeWalker(Accessible* aContext, nsIContent* aContent, uint32_t aFlags) :
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mDoc(aContext->Document()), mContext(aContext), mAnchorNode(aContent),
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mFlags(aFlags)
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{
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NS_ASSERTION(aContent, "No node for the accessible tree walker!");
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mChildFilter = mContext->CanHaveAnonChildren() ?
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nsIContent::eAllChildren : nsIContent::eAllButXBL;
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mChildFilter |= nsIContent::eSkipPlaceholderContent;
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if (aContent)
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PushState(aContent);
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MOZ_COUNT_CTOR(TreeWalker);
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}
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TreeWalker::~TreeWalker()
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{
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MOZ_COUNT_DTOR(TreeWalker);
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}
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////////////////////////////////////////////////////////////////////////////////
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// TreeWalker: private
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Accessible*
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TreeWalker::NextChild()
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{
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if (mStateStack.IsEmpty())
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return nullptr;
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ChildrenIterator* top = &mStateStack[mStateStack.Length() - 1];
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while (top) {
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Accessible* child = nullptr;
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bool skipSubtree = false;
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while (nsIContent* childNode = Next(top, &child, &skipSubtree)) {
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if (child)
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return child;
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// Walk down into subtree to find accessibles.
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if (!skipSubtree && childNode->IsElement())
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top = PushState(childNode);
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}
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top = PopState();
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}
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// If we traversed the whole subtree of the anchor node. Move to next node
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// relative anchor node within the context subtree if possible.
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if (mFlags != eWalkContextTree)
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return nullptr;
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nsINode* contextNode = mContext->GetNode();
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while (mAnchorNode != contextNode) {
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nsINode* parentNode = mAnchorNode->GetFlattenedTreeParent();
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if (!parentNode || !parentNode->IsElement())
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return nullptr;
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nsIContent* parent = parentNode->AsElement();
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top = PushState(parent);
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while (nsIContent* childNode = Next(top)) {
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if (childNode == mAnchorNode) {
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mAnchorNode = parent;
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return NextChild();
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}
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}
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// XXX We really should never get here, it means we're trying to find an
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// accessible for a dom node where iterating over its parent's children
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// doesn't return it. However this sometimes happens when we're asked for
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// the nearest accessible to place holder content which we ignore.
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mAnchorNode = parent;
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}
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return nullptr;
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}
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nsIContent*
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TreeWalker::Next(ChildrenIterator* aIter, Accessible** aAccesible,
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bool* aSkipSubtree)
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{
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nsIContent* childEl = aIter->mDOMIter.GetNextChild();
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if (!aAccesible)
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return childEl;
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*aAccesible = nullptr;
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*aSkipSubtree = false;
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if (childEl) {
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Accessible* accessible = mFlags & eWalkCache ?
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mDoc->GetAccessible(childEl) :
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GetAccService()->GetOrCreateAccessible(childEl, mContext, aSkipSubtree);
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// Ignore the accessible and its subtree if it was repositioned by means of
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// aria-owns.
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if (accessible) {
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if (accessible->IsRelocated()) {
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*aSkipSubtree = true;
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} else {
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*aAccesible = accessible;
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}
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}
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return childEl;
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}
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// At last iterate over ARIA owned children.
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Accessible* parent = mDoc->GetAccessible(aIter->mDOMIter.Parent());
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if (parent) {
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Accessible* child = mDoc->ARIAOwnedAt(parent, aIter->mARIAOwnsIdx++);
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if (child) {
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*aAccesible = child;
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return child->GetContent();
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}
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}
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return nullptr;
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}
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TreeWalker::ChildrenIterator*
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TreeWalker::PopState()
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{
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size_t length = mStateStack.Length();
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mStateStack.RemoveElementAt(length - 1);
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return mStateStack.IsEmpty() ? nullptr : &mStateStack[mStateStack.Length() - 1];
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}
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