зеркало из https://github.com/mozilla/gecko-dev.git
140 строки
4.1 KiB
C++
140 строки
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) :
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mDoc(aContext->Document()), mContext(aContext), mAnchorNode(nullptr),
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mARIAOwnsIdx(0),
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mChildFilter(nsIContent::eSkipPlaceholderContent), mFlags(0)
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{
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mChildFilter |= mContext->NoXBLKids() ?
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nsIContent::eAllButXBL : nsIContent::eAllChildren;
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mAnchorNode = mContext->IsDoc() ?
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mDoc->DocumentNode()->GetRootElement() : mContext->GetContent();
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if (mAnchorNode) {
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PushState(mAnchorNode);
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}
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MOZ_COUNT_CTOR(TreeWalker);
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}
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TreeWalker::
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TreeWalker(Accessible* aContext, nsIContent* aAnchorNode, uint32_t aFlags) :
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mDoc(aContext->Document()), mContext(aContext), mAnchorNode(aAnchorNode),
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mARIAOwnsIdx(0),
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mChildFilter(nsIContent::eSkipPlaceholderContent), mFlags(aFlags)
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{
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MOZ_ASSERT(aAnchorNode, "No anchor node for the accessible tree walker");
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MOZ_ASSERT(mDoc->GetAccessibleOrContainer(aAnchorNode) == mContext,
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"Unexpected anchor node was given");
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mChildFilter |= mContext->NoXBLKids() ?
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nsIContent::eAllButXBL : nsIContent::eAllChildren;
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PushState(aAnchorNode);
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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::Next()
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{
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if (mStateStack.IsEmpty()) {
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return mDoc->ARIAOwnedAt(mContext, mARIAOwnsIdx++);
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}
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dom::AllChildrenIterator* top = &mStateStack[mStateStack.Length() - 1];
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while (top) {
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while (nsIContent* childNode = top->GetNextChild()) {
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bool skipSubtree = false;
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Accessible* child = nullptr;
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if (mFlags & eWalkCache) {
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child = mDoc->GetAccessible(childNode);
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}
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else if (mContext->IsAcceptableChild(childNode)) {
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child = GetAccService()->
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GetOrCreateAccessible(childNode, mContext, &skipSubtree);
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}
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// Ignore the accessible and its subtree if it was repositioned by means
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// of aria-owns.
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if (child) {
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if (child->IsRelocated()) {
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continue;
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}
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return child;
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}
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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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}
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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 Next();
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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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if (top->Seek(mAnchorNode)) {
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mAnchorNode = parent;
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return Next();
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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 Next();
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}
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dom::AllChildrenIterator*
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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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