michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "TreeWalker.h"
michael@0: 
michael@0: #include "Accessible.h"
michael@0: #include "nsAccessibilityService.h"
michael@0: #include "DocAccessible.h"
michael@0: 
michael@0: #include "mozilla/dom/Element.h"
michael@0: 
michael@0: using namespace mozilla::a11y;
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // WalkState
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace a11y {
michael@0: 
michael@0: struct WalkState
michael@0: {
michael@0:   WalkState(nsIContent *aContent) :
michael@0:     content(aContent), childIdx(0), prevState(nullptr) {}
michael@0: 
michael@0:   nsCOMPtr<nsIContent> content;
michael@0:   nsCOMPtr<nsINodeList> childList;
michael@0:   uint32_t childIdx;
michael@0:   WalkState *prevState;
michael@0: };
michael@0: 
michael@0: } // namespace a11y
michael@0: } // namespace mozilla
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // TreeWalker
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: TreeWalker::
michael@0:   TreeWalker(Accessible* aContext, nsIContent* aContent, uint32_t aFlags) :
michael@0:   mDoc(aContext->Document()), mContext(aContext),
michael@0:   mFlags(aFlags), mState(nullptr)
michael@0: {
michael@0:   NS_ASSERTION(aContent, "No node for the accessible tree walker!");
michael@0: 
michael@0:   if (aContent)
michael@0:     mState = new WalkState(aContent);
michael@0: 
michael@0:   mChildFilter = mContext->CanHaveAnonChildren() ?
michael@0:     nsIContent::eAllChildren : nsIContent::eAllButXBL;
michael@0: 
michael@0:   mChildFilter |= nsIContent::eSkipPlaceholderContent;
michael@0: 
michael@0:   MOZ_COUNT_CTOR(TreeWalker);
michael@0: }
michael@0: 
michael@0: TreeWalker::~TreeWalker()
michael@0: {
michael@0:   // Clear state stack from memory
michael@0:   while (mState)
michael@0:     PopState();
michael@0: 
michael@0:   MOZ_COUNT_DTOR(TreeWalker);
michael@0: }
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // TreeWalker: private
michael@0: 
michael@0: Accessible*
michael@0: TreeWalker::NextChildInternal(bool aNoWalkUp)
michael@0: {
michael@0:   if (!mState || !mState->content)
michael@0:     return nullptr;
michael@0: 
michael@0:   if (!mState->childList)
michael@0:     mState->childList = mState->content->GetChildren(mChildFilter);
michael@0: 
michael@0:   uint32_t length = 0;
michael@0:   if (mState->childList)
michael@0:     mState->childList->GetLength(&length);
michael@0: 
michael@0:   while (mState->childIdx < length) {
michael@0:     nsIContent* childNode = mState->childList->Item(mState->childIdx);
michael@0:     mState->childIdx++;
michael@0: 
michael@0:     bool isSubtreeHidden = false;
michael@0:     Accessible* accessible = mFlags & eWalkCache ?
michael@0:       mDoc->GetAccessible(childNode) :
michael@0:       GetAccService()->GetOrCreateAccessible(childNode, mContext,
michael@0:                                              &isSubtreeHidden);
michael@0: 
michael@0:     if (accessible)
michael@0:       return accessible;
michael@0: 
michael@0:     // Walk down into subtree to find accessibles.
michael@0:     if (!isSubtreeHidden) {
michael@0:       PushState(childNode);
michael@0:       accessible = NextChildInternal(true);
michael@0:       if (accessible)
michael@0:         return accessible;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   // No more children, get back to the parent.
michael@0:   nsIContent* anchorNode = mState->content;
michael@0:   PopState();
michael@0:   if (aNoWalkUp)
michael@0:     return nullptr;
michael@0: 
michael@0:   if (mState)
michael@0:     return NextChildInternal(false);
michael@0: 
michael@0:   // If we traversed the whole subtree of the anchor node. Move to next node
michael@0:   // relative anchor node within the context subtree if possible.
michael@0:   if (mFlags != eWalkContextTree)
michael@0:     return nullptr;
michael@0: 
michael@0:   while (anchorNode != mContext->GetNode()) {
michael@0:     nsINode* parentNode = anchorNode->GetFlattenedTreeParent();
michael@0:     if (!parentNode || !parentNode->IsElement())
michael@0:       return nullptr;
michael@0: 
michael@0:     PushState(parentNode->AsElement());
michael@0:     mState->childList = mState->content->GetChildren(mChildFilter);
michael@0:     length = 0;
michael@0:     if (mState->childList)
michael@0:       mState->childList->GetLength(&length);
michael@0: 
michael@0:     while (mState->childIdx < length) {
michael@0:       nsIContent* childNode = mState->childList->Item(mState->childIdx);
michael@0:       mState->childIdx++;
michael@0:       if (childNode == anchorNode)
michael@0:         return NextChildInternal(false);
michael@0:     }
michael@0:     PopState();
michael@0: 
michael@0:     anchorNode = parentNode->AsElement();
michael@0:   }
michael@0: 
michael@0:   return nullptr;
michael@0: }
michael@0: 
michael@0: void
michael@0: TreeWalker::PopState()
michael@0: {
michael@0:   WalkState* prevToLastState = mState->prevState;
michael@0:   delete mState;
michael@0:   mState = prevToLastState;
michael@0: }
michael@0: 
michael@0: void
michael@0: TreeWalker::PushState(nsIContent* aContent)
michael@0: {
michael@0:   WalkState* nextToLastState = new WalkState(aContent);
michael@0:   nextToLastState->prevState = mState;
michael@0:   mState = nextToLastState;
michael@0: }