The Tor Browser: dom/xslt/xpath/nsXPathResult.cpp@97036ab72558 (annotated)

dom/xslt/xpath/nsXPathResult.cpp@97036ab72558 (annotated)

dom/xslt/xpath/nsXPathResult.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "nsXPathResult.h"
 #include "txExprResult.h"
 #include "txNodeSet.h"
 #include "nsError.h"
 #include "mozilla/dom/Attr.h"
 #include "mozilla/dom/Element.h"
 #include "nsDOMClassInfoID.h"
 #include "nsIDOMNode.h"
 #include "nsIDOMDocument.h"
 #include "nsDOMString.h"
 #include "txXPathTreeWalker.h"
 #include "nsCycleCollectionParticipant.h"
 using namespace mozilla::dom;
 nsXPathResult::nsXPathResult() : mDocument(nullptr),
                                  mCurrentPos(0),
                                  mResultType(ANY_TYPE),
                                  mInvalidIteratorState(true),
                                  mBooleanResult(false),
                                  mNumberResult(0)
 {
 }
 nsXPathResult::nsXPathResult(const nsXPathResult &aResult)
     : mResult(aResult.mResult),
       mResultNodes(aResult.mResultNodes),
       mDocument(aResult.mDocument),
       mCurrentPos(0),
       mResultType(aResult.mResultType),
       mContextNode(aResult.mContextNode),
       mInvalidIteratorState(aResult.mInvalidIteratorState)
 {
     if (mDocument) {
         mDocument->AddMutationObserver(this);
     }
 }
 nsXPathResult::~nsXPathResult()
 {
     RemoveObserver();
 }
 NS_IMPL_CYCLE_COLLECTION_CLASS(nsXPathResult)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsXPathResult)
     {
         tmp->RemoveObserver();
     }
     NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsXPathResult)
     NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument)
     NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mResultNodes)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 NS_IMPL_CYCLE_COLLECTING_ADDREF(nsXPathResult)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(nsXPathResult)
 DOMCI_DATA(XPathResult, nsXPathResult)
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsXPathResult)
     NS_INTERFACE_MAP_ENTRY(nsIDOMXPathResult)
     NS_INTERFACE_MAP_ENTRY(nsIMutationObserver)
     NS_INTERFACE_MAP_ENTRY(nsIXPathResult)
     NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMXPathResult)
     NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(XPathResult)
 NS_INTERFACE_MAP_END
 void
 nsXPathResult::RemoveObserver()
 {
     if (mDocument) {
         mDocument->RemoveMutationObserver(this);
     }
 }
 NS_IMETHODIMP
 nsXPathResult::GetResultType(uint16_t *aResultType)
 {
     *aResultType = mResultType;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsXPathResult::GetNumberValue(double *aNumberValue)
 {
     if (mResultType != NUMBER_TYPE) {
         return NS_ERROR_DOM_TYPE_ERR;
     }
     *aNumberValue = mNumberResult;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsXPathResult::GetStringValue(nsAString &aStringValue)
 {
     if (mResultType != STRING_TYPE) {
         return NS_ERROR_DOM_TYPE_ERR;
     }
     aStringValue = mStringResult;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsXPathResult::GetBooleanValue(bool *aBooleanValue)
 {
     if (mResultType != BOOLEAN_TYPE) {
         return NS_ERROR_DOM_TYPE_ERR;
     }
     *aBooleanValue = mBooleanResult;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsXPathResult::GetSingleNodeValue(nsIDOMNode **aSingleNodeValue)
 {
     if (!isNode()) {
         return NS_ERROR_DOM_TYPE_ERR;
     }
     if (mResultNodes.Count() > 0) {
         NS_ADDREF(*aSingleNodeValue = mResultNodes[0]);
     }
     else {
         *aSingleNodeValue = nullptr;
     }
     return NS_OK;
 }
 NS_IMETHODIMP
 nsXPathResult::GetInvalidIteratorState(bool *aInvalidIteratorState)
 {
     *aInvalidIteratorState = isIterator() && mInvalidIteratorState;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsXPathResult::GetSnapshotLength(uint32_t *aSnapshotLength)
 {
     if (!isSnapshot()) {
         return NS_ERROR_DOM_TYPE_ERR;
     }
     *aSnapshotLength = (uint32_t)mResultNodes.Count();
     return NS_OK;
 }
 NS_IMETHODIMP
 nsXPathResult::IterateNext(nsIDOMNode **aResult)
 {
     if (!isIterator()) {
         return NS_ERROR_DOM_TYPE_ERR;
     }
     if (mDocument) {
         mDocument->FlushPendingNotifications(Flush_Content);
     }
     if (mInvalidIteratorState) {
         return NS_ERROR_DOM_INVALID_STATE_ERR;
     }
     if (mCurrentPos < (uint32_t)mResultNodes.Count()) {
         NS_ADDREF(*aResult = mResultNodes[mCurrentPos++]);
     }
     else {
         *aResult = nullptr;
     }
     return NS_OK;
 }
 NS_IMETHODIMP
 nsXPathResult::SnapshotItem(uint32_t aIndex, nsIDOMNode **aResult)
 {
     if (!isSnapshot()) {
         return NS_ERROR_DOM_TYPE_ERR;
     }
     NS_IF_ADDREF(*aResult = mResultNodes.SafeObjectAt(aIndex));
     return NS_OK;
 }
 void
 nsXPathResult::NodeWillBeDestroyed(const nsINode* aNode)
 {
     nsCOMPtr<nsIMutationObserver> kungFuDeathGrip(this);
     // Set to null to avoid unregistring unnecessarily
     mDocument = nullptr;
     Invalidate(aNode->IsNodeOfType(nsINode::eCONTENT) ?
                static_cast<const nsIContent*>(aNode) : nullptr);
 }
 void
 nsXPathResult::CharacterDataChanged(nsIDocument* aDocument,
                                     nsIContent *aContent,
                                     CharacterDataChangeInfo* aInfo)
 {
     Invalidate(aContent);
 }
 void
 nsXPathResult::AttributeChanged(nsIDocument* aDocument,
                                 Element* aElement,
                                 int32_t aNameSpaceID,
                                 nsIAtom* aAttribute,
                                 int32_t aModType)
 {
     Invalidate(aElement);
 }
 void
 nsXPathResult::ContentAppended(nsIDocument* aDocument,
                                nsIContent* aContainer,
                                nsIContent* aFirstNewContent,
                                int32_t aNewIndexInContainer)
 {
     Invalidate(aContainer);
 }
 void
 nsXPathResult::ContentInserted(nsIDocument* aDocument,
                                nsIContent* aContainer,
                                nsIContent* aChild,
                                int32_t aIndexInContainer)
 {
     Invalidate(aContainer);
 }
 void
 nsXPathResult::ContentRemoved(nsIDocument* aDocument,
                               nsIContent* aContainer,
                               nsIContent* aChild,
                               int32_t aIndexInContainer,
                               nsIContent* aPreviousSibling)
 {
     Invalidate(aContainer);
 }
 nsresult
 nsXPathResult::SetExprResult(txAExprResult* aExprResult, uint16_t aResultType,
                              nsINode* aContextNode)
 {
     MOZ_ASSERT(aExprResult);
     if ((isSnapshot(aResultType) || isIterator(aResultType) ||
          isNode(aResultType)) &&
         aExprResult->getResultType() != txAExprResult::NODESET) {
         // The DOM spec doesn't really say what should happen when reusing an
         // XPathResult and an error is thrown. Let's not touch the XPathResult
         // in that case.
         return NS_ERROR_DOM_TYPE_ERR;
     }
     mResultType = aResultType;
     mContextNode = do_GetWeakReference(aContextNode);
     if (mDocument) {
         mDocument->RemoveMutationObserver(this);
         mDocument = nullptr;
     }
     mResultNodes.Clear();
     // XXX This will keep the recycler alive, should we clear it?
     mResult = aExprResult;
     switch (mResultType) {
         case BOOLEAN_TYPE:
         {
             mBooleanResult = mResult->booleanValue();
             break;
         }
         case NUMBER_TYPE:
         {
             mNumberResult = mResult->numberValue();
             break;
         }
         case STRING_TYPE:
         {
             mResult->stringValue(mStringResult);
             break;
         }
         default:
         {
             MOZ_ASSERT(isNode() || isIterator() || isSnapshot());
         }
     }
     if (aExprResult->getResultType() == txAExprResult::NODESET) {
         txNodeSet *nodeSet = static_cast<txNodeSet*>(aExprResult);
         nsCOMPtr<nsIDOMNode> node;
         int32_t i, count = nodeSet->size();
         for (i = 0; i < count; ++i) {
             txXPathNativeNode::getNode(nodeSet->get(i), getter_AddRefs(node));
             if (node) {
                 mResultNodes.AppendObject(node);
             }
         }
         if (count > 0) {
             mResult = nullptr;
         }
     }
     if (!isIterator()) {
         return NS_OK;
     }
     mInvalidIteratorState = false;
     if (mResultNodes.Count() > 0) {
         // If we support the document() function in DOM-XPath we need to
         // observe all documents that we have resultnodes in.
         nsCOMPtr<nsIDOMDocument> document;
         mResultNodes[0]->GetOwnerDocument(getter_AddRefs(document));
         if (document) {
             mDocument = do_QueryInterface(document);
         }
         else {
             mDocument = do_QueryInterface(mResultNodes[0]);
         }
         NS_ASSERTION(mDocument, "We need a document!");
         if (mDocument) {
             mDocument->AddMutationObserver(this);
         }
     }
     return NS_OK;
 }
 void
 nsXPathResult::Invalidate(const nsIContent* aChangeRoot)
 {
     nsCOMPtr<nsINode> contextNode = do_QueryReferent(mContextNode);
     if (contextNode && aChangeRoot && aChangeRoot->GetBindingParent()) {
         // If context node is in anonymous content, changes to
         // non-anonymous content need to invalidate the XPathResult. If
         // the changes are happening in a different anonymous trees, no
         // invalidation should happen.
         nsIContent* ctxBindingParent = nullptr;
         if (contextNode->IsNodeOfType(nsINode::eCONTENT)) {
             ctxBindingParent =
                 static_cast<nsIContent*>(contextNode.get())
                     ->GetBindingParent();
         } else if (contextNode->IsNodeOfType(nsINode::eATTRIBUTE)) {
             Element* parent =
               static_cast<Attr*>(contextNode.get())->GetElement();
             if (parent) {
                 ctxBindingParent = parent->GetBindingParent();
             }
         }
         if (ctxBindingParent != aChangeRoot->GetBindingParent()) {
           return;
         }
     }
     mInvalidIteratorState = true;
     // Make sure nulling out mDocument is the last thing we do.
     if (mDocument) {
         mDocument->RemoveMutationObserver(this);
         mDocument = nullptr;
     }
 }
 nsresult
 nsXPathResult::GetExprResult(txAExprResult** aExprResult)
 {
     if (isIterator() && mInvalidIteratorState) {
         return NS_ERROR_DOM_INVALID_STATE_ERR;
     }
     if (mResult) {
         NS_ADDREF(*aExprResult = mResult);
         return NS_OK;
     }
     if (mResultNodes.Count() == 0) {
         return NS_ERROR_DOM_INVALID_STATE_ERR;
     }
     nsRefPtr<txNodeSet> nodeSet = new txNodeSet(nullptr);
     if (!nodeSet) {
         return NS_ERROR_OUT_OF_MEMORY;
     }
     uint32_t i, count = mResultNodes.Count();
     for (i = 0; i < count; ++i) {
         nsAutoPtr<txXPathNode> node(txXPathNativeNode::createXPathNode(mResultNodes[i]));
         if (!node) {
             return NS_ERROR_OUT_OF_MEMORY;
         }
         nodeSet->append(*node);
     }
     NS_ADDREF(*aExprResult = nodeSet);
     return NS_OK;
 }
 nsresult
 nsXPathResult::Clone(nsIXPathResult **aResult)
 {
     *aResult = nullptr;
     if (isIterator() && mInvalidIteratorState) {
         return NS_ERROR_DOM_INVALID_STATE_ERR;
     }
     nsCOMPtr<nsIXPathResult> result = new nsXPathResult(*this);
     if (!result) {
         return NS_ERROR_OUT_OF_MEMORY;
     }
     result.swap(*aResult);
     return NS_OK;
 }

The Tor Browser / annotate

dom/xslt/xpath/nsXPathResult.cpp@97036ab72558 (annotated)

dom/xslt/xpath/nsXPathResult.cpp