1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/accessible/src/base/TreeWalker.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,159 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include "TreeWalker.h"
1.10 +
1.11 +#include "Accessible.h"
1.12 +#include "nsAccessibilityService.h"
1.13 +#include "DocAccessible.h"
1.14 +
1.15 +#include "mozilla/dom/Element.h"
1.16 +
1.17 +using namespace mozilla::a11y;
1.18 +
1.19 +////////////////////////////////////////////////////////////////////////////////
1.20 +// WalkState
1.21 +////////////////////////////////////////////////////////////////////////////////
1.22 +
1.23 +namespace mozilla {
1.24 +namespace a11y {
1.25 +
1.26 +struct WalkState
1.27 +{
1.28 + WalkState(nsIContent *aContent) :
1.29 + content(aContent), childIdx(0), prevState(nullptr) {}
1.30 +
1.31 + nsCOMPtr<nsIContent> content;
1.32 + nsCOMPtr<nsINodeList> childList;
1.33 + uint32_t childIdx;
1.34 + WalkState *prevState;
1.35 +};
1.36 +
1.37 +} // namespace a11y
1.38 +} // namespace mozilla
1.39 +
1.40 +////////////////////////////////////////////////////////////////////////////////
1.41 +// TreeWalker
1.42 +////////////////////////////////////////////////////////////////////////////////
1.43 +
1.44 +TreeWalker::
1.45 + TreeWalker(Accessible* aContext, nsIContent* aContent, uint32_t aFlags) :
1.46 + mDoc(aContext->Document()), mContext(aContext),
1.47 + mFlags(aFlags), mState(nullptr)
1.48 +{
1.49 + NS_ASSERTION(aContent, "No node for the accessible tree walker!");
1.50 +
1.51 + if (aContent)
1.52 + mState = new WalkState(aContent);
1.53 +
1.54 + mChildFilter = mContext->CanHaveAnonChildren() ?
1.55 + nsIContent::eAllChildren : nsIContent::eAllButXBL;
1.56 +
1.57 + mChildFilter |= nsIContent::eSkipPlaceholderContent;
1.58 +
1.59 + MOZ_COUNT_CTOR(TreeWalker);
1.60 +}
1.61 +
1.62 +TreeWalker::~TreeWalker()
1.63 +{
1.64 + // Clear state stack from memory
1.65 + while (mState)
1.66 + PopState();
1.67 +
1.68 + MOZ_COUNT_DTOR(TreeWalker);
1.69 +}
1.70 +
1.71 +////////////////////////////////////////////////////////////////////////////////
1.72 +// TreeWalker: private
1.73 +
1.74 +Accessible*
1.75 +TreeWalker::NextChildInternal(bool aNoWalkUp)
1.76 +{
1.77 + if (!mState || !mState->content)
1.78 + return nullptr;
1.79 +
1.80 + if (!mState->childList)
1.81 + mState->childList = mState->content->GetChildren(mChildFilter);
1.82 +
1.83 + uint32_t length = 0;
1.84 + if (mState->childList)
1.85 + mState->childList->GetLength(&length);
1.86 +
1.87 + while (mState->childIdx < length) {
1.88 + nsIContent* childNode = mState->childList->Item(mState->childIdx);
1.89 + mState->childIdx++;
1.90 +
1.91 + bool isSubtreeHidden = false;
1.92 + Accessible* accessible = mFlags & eWalkCache ?
1.93 + mDoc->GetAccessible(childNode) :
1.94 + GetAccService()->GetOrCreateAccessible(childNode, mContext,
1.95 + &isSubtreeHidden);
1.96 +
1.97 + if (accessible)
1.98 + return accessible;
1.99 +
1.100 + // Walk down into subtree to find accessibles.
1.101 + if (!isSubtreeHidden) {
1.102 + PushState(childNode);
1.103 + accessible = NextChildInternal(true);
1.104 + if (accessible)
1.105 + return accessible;
1.106 + }
1.107 + }
1.108 +
1.109 + // No more children, get back to the parent.
1.110 + nsIContent* anchorNode = mState->content;
1.111 + PopState();
1.112 + if (aNoWalkUp)
1.113 + return nullptr;
1.114 +
1.115 + if (mState)
1.116 + return NextChildInternal(false);
1.117 +
1.118 + // If we traversed the whole subtree of the anchor node. Move to next node
1.119 + // relative anchor node within the context subtree if possible.
1.120 + if (mFlags != eWalkContextTree)
1.121 + return nullptr;
1.122 +
1.123 + while (anchorNode != mContext->GetNode()) {
1.124 + nsINode* parentNode = anchorNode->GetFlattenedTreeParent();
1.125 + if (!parentNode || !parentNode->IsElement())
1.126 + return nullptr;
1.127 +
1.128 + PushState(parentNode->AsElement());
1.129 + mState->childList = mState->content->GetChildren(mChildFilter);
1.130 + length = 0;
1.131 + if (mState->childList)
1.132 + mState->childList->GetLength(&length);
1.133 +
1.134 + while (mState->childIdx < length) {
1.135 + nsIContent* childNode = mState->childList->Item(mState->childIdx);
1.136 + mState->childIdx++;
1.137 + if (childNode == anchorNode)
1.138 + return NextChildInternal(false);
1.139 + }
1.140 + PopState();
1.141 +
1.142 + anchorNode = parentNode->AsElement();
1.143 + }
1.144 +
1.145 + return nullptr;
1.146 +}
1.147 +
1.148 +void
1.149 +TreeWalker::PopState()
1.150 +{
1.151 + WalkState* prevToLastState = mState->prevState;
1.152 + delete mState;
1.153 + mState = prevToLastState;
1.154 +}
1.155 +
1.156 +void
1.157 +TreeWalker::PushState(nsIContent* aContent)
1.158 +{
1.159 + WalkState* nextToLastState = new WalkState(aContent);
1.160 + nextToLastState->prevState = mState;
1.161 + mState = nextToLastState;
1.162 +}
