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accessible/src/base/TreeWalker.cpp@b8a032363ba2 (annotated)

accessible/src/base/TreeWalker.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Thu, 22 Jan 2015 13:21:57 +0100

branch

TOR_BUG_9701

changeset 15

b8a032363ba2

permissions

-rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

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