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comparison: accessible/src/base/TreeWalker.cpp
accessible/src/base/TreeWalker.cpp
- changeset 0
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| 1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
| 2 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 #include "TreeWalker.h" | |
| 7 | |
| 8 #include "Accessible.h" | |
| 9 #include "nsAccessibilityService.h" | |
| 10 #include "DocAccessible.h" | |
| 11 | |
| 12 #include "mozilla/dom/Element.h" | |
| 13 | |
| 14 using namespace mozilla::a11y; | |
| 15 | |
| 16 //////////////////////////////////////////////////////////////////////////////// | |
| 17 // WalkState | |
| 18 //////////////////////////////////////////////////////////////////////////////// | |
| 19 | |
| 20 namespace mozilla { | |
| 21 namespace a11y { | |
| 22 | |
| 23 struct WalkState | |
| 24 { | |
| 25 WalkState(nsIContent *aContent) : | |
| 26 content(aContent), childIdx(0), prevState(nullptr) {} | |
| 27 | |
| 28 nsCOMPtr<nsIContent> content; | |
| 29 nsCOMPtr<nsINodeList> childList; | |
| 30 uint32_t childIdx; | |
| 31 WalkState *prevState; | |
| 32 }; | |
| 33 | |
| 34 } // namespace a11y | |
| 35 } // namespace mozilla | |
| 36 | |
| 37 //////////////////////////////////////////////////////////////////////////////// | |
| 38 // TreeWalker | |
| 39 //////////////////////////////////////////////////////////////////////////////// | |
| 40 | |
| 41 TreeWalker:: | |
| 42 TreeWalker(Accessible* aContext, nsIContent* aContent, uint32_t aFlags) : | |
| 43 mDoc(aContext->Document()), mContext(aContext), | |
| 44 mFlags(aFlags), mState(nullptr) | |
| 45 { | |
| 46 NS_ASSERTION(aContent, "No node for the accessible tree walker!"); | |
| 47 | |
| 48 if (aContent) | |
| 49 mState = new WalkState(aContent); | |
| 50 | |
| 51 mChildFilter = mContext->CanHaveAnonChildren() ? | |
| 52 nsIContent::eAllChildren : nsIContent::eAllButXBL; | |
| 53 | |
| 54 mChildFilter |= nsIContent::eSkipPlaceholderContent; | |
| 55 | |
| 56 MOZ_COUNT_CTOR(TreeWalker); | |
| 57 } | |
| 58 | |
| 59 TreeWalker::~TreeWalker() | |
| 60 { | |
| 61 // Clear state stack from memory | |
| 62 while (mState) | |
| 63 PopState(); | |
| 64 | |
| 65 MOZ_COUNT_DTOR(TreeWalker); | |
| 66 } | |
| 67 | |
| 68 //////////////////////////////////////////////////////////////////////////////// | |
| 69 // TreeWalker: private | |
| 70 | |
| 71 Accessible* | |
| 72 TreeWalker::NextChildInternal(bool aNoWalkUp) | |
| 73 { | |
| 74 if (!mState || !mState->content) | |
| 75 return nullptr; | |
| 76 | |
| 77 if (!mState->childList) | |
| 78 mState->childList = mState->content->GetChildren(mChildFilter); | |
| 79 | |
| 80 uint32_t length = 0; | |
| 81 if (mState->childList) | |
| 82 mState->childList->GetLength(&length); | |
| 83 | |
| 84 while (mState->childIdx < length) { | |
| 85 nsIContent* childNode = mState->childList->Item(mState->childIdx); | |
| 86 mState->childIdx++; | |
| 87 | |
| 88 bool isSubtreeHidden = false; | |
| 89 Accessible* accessible = mFlags & eWalkCache ? | |
| 90 mDoc->GetAccessible(childNode) : | |
| 91 GetAccService()->GetOrCreateAccessible(childNode, mContext, | |
| 92 &isSubtreeHidden); | |
| 93 | |
| 94 if (accessible) | |
| 95 return accessible; | |
| 96 | |
| 97 // Walk down into subtree to find accessibles. | |
| 98 if (!isSubtreeHidden) { | |
| 99 PushState(childNode); | |
| 100 accessible = NextChildInternal(true); | |
| 101 if (accessible) | |
| 102 return accessible; | |
| 103 } | |
| 104 } | |
| 105 | |
| 106 // No more children, get back to the parent. | |
| 107 nsIContent* anchorNode = mState->content; | |
| 108 PopState(); | |
| 109 if (aNoWalkUp) | |
| 110 return nullptr; | |
| 111 | |
| 112 if (mState) | |
| 113 return NextChildInternal(false); | |
| 114 | |
| 115 // If we traversed the whole subtree of the anchor node. Move to next node | |
| 116 // relative anchor node within the context subtree if possible. | |
| 117 if (mFlags != eWalkContextTree) | |
| 118 return nullptr; | |
| 119 | |
| 120 while (anchorNode != mContext->GetNode()) { | |
| 121 nsINode* parentNode = anchorNode->GetFlattenedTreeParent(); | |
| 122 if (!parentNode || !parentNode->IsElement()) | |
| 123 return nullptr; | |
| 124 | |
| 125 PushState(parentNode->AsElement()); | |
| 126 mState->childList = mState->content->GetChildren(mChildFilter); | |
| 127 length = 0; | |
| 128 if (mState->childList) | |
| 129 mState->childList->GetLength(&length); | |
| 130 | |
| 131 while (mState->childIdx < length) { | |
| 132 nsIContent* childNode = mState->childList->Item(mState->childIdx); | |
| 133 mState->childIdx++; | |
| 134 if (childNode == anchorNode) | |
| 135 return NextChildInternal(false); | |
| 136 } | |
| 137 PopState(); | |
| 138 | |
| 139 anchorNode = parentNode->AsElement(); | |
| 140 } | |
| 141 | |
| 142 return nullptr; | |
| 143 } | |
| 144 | |
| 145 void | |
| 146 TreeWalker::PopState() | |
| 147 { | |
| 148 WalkState* prevToLastState = mState->prevState; | |
| 149 delete mState; | |
| 150 mState = prevToLastState; | |
| 151 } | |
| 152 | |
| 153 void | |
| 154 TreeWalker::PushState(nsIContent* aContent) | |
| 155 { | |
| 156 WalkState* nextToLastState = new WalkState(aContent); | |
| 157 nextToLastState->prevState = mState; | |
| 158 mState = nextToLastState; | |
| 159 } |
