[SCM] WebKit Debian packaging branch, debian/unstable, updated. debian/1.1.18-1-697-g2f78b87

[dimich at chromium.org]

The following commit has been merged in the debian/unstable branch:
commit 73d07f2c4605f8e0ce2e0e8c5b952004650bebe0
Author: dimich at chromium.org <dimich at chromium.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Date:   Fri Jan 15 21:47:15 2010 +0000

    Need to ensure that Document::postTask does not provide the Task with a dangling pointer to destroyed Document
    https://bugs.webkit.org/show_bug.cgi?id=31633
    
    Reviewed by Darin Adler.
    
    Don't see a way to add test for it, we don't have a way to reproduce the issue currently.
    
    * dom/Document.cpp:
    (WebCore::DocumentWeakReference::DocumentWeakReference):
    (WebCore::DocumentWeakReference::document):
    (WebCore::DocumentWeakReference::clear):
    (WebCore::Document::Document): Create a weak reference to this Document.
    (WebCore::Document::~Document): Clear the weak pointer, preventing further execution of tasks.
    (WebCore::PerformTaskContext::PerformTaskContext):
    (WebCore::performTask): Check if the documentWeakReference is cleared by Document destructor - in this case do not run the task.
    (WebCore::Document::postTask):
    * dom/Document.h:
    (WebCore::DocumentWeakReference::create):
    
    git-svn-id: http://svn.webkit.org/repository/webkit/trunk@53345 268f45cc-cd09-0410-ab3c-d52691b4dbfc

diff --git a/WebCore/ChangeLog b/WebCore/ChangeLog
index 01bf65e..e3e6f56 100644
--- a/WebCore/ChangeLog
+++ b/WebCore/ChangeLog
@@ -1,3 +1,24 @@
+2010-01-15  Dmitry Titov  <dimich at chromium.org>
+
+        Reviewed by Darin Adler.
+
+        Need to ensure that Document::postTask does not provide the Task with a dangling pointer to destroyed Document
+        https://bugs.webkit.org/show_bug.cgi?id=31633
+
+        Don't see a way to add test for it, we don't have a way to reproduce the issue currently.
+
+        * dom/Document.cpp:
+        (WebCore::DocumentWeakReference::DocumentWeakReference):
+        (WebCore::DocumentWeakReference::document):
+        (WebCore::DocumentWeakReference::clear):
+        (WebCore::Document::Document): Create a weak reference to this Document.
+        (WebCore::Document::~Document): Clear the weak pointer, preventing further execution of tasks.
+        (WebCore::PerformTaskContext::PerformTaskContext):
+        (WebCore::performTask): Check if the documentWeakReference is cleared by Document destructor - in this case do not run the task.
+        (WebCore::Document::postTask):
+        * dom/Document.h:
+        (WebCore::DocumentWeakReference::create):
+
 2010-01-15  Vitaly Repeshko  <vitalyr at chromium.org>
 
         Reviewed by David Levin.
diff --git a/WebCore/dom/Document.cpp b/WebCore/dom/Document.cpp
index 5c977ad..457bcc3 100644
--- a/WebCore/dom/Document.cpp
+++ b/WebCore/dom/Document.cpp
@@ -367,6 +367,7 @@ Document::Document(Frame* frame, bool isXHTML)
 #if ENABLE(WML)
     , m_containsWMLContent(false)
 #endif
+    , m_weakReference(DocumentWeakReference::create(this))
 {
     m_document = this;
 
@@ -516,6 +517,8 @@ Document::~Document()
 
     if (m_styleSheets)
         m_styleSheets->documentDestroyed();
+
+    m_weakReference->clear();
 }
 
 #if USE(JSC)
@@ -4696,21 +4699,27 @@ private:
 };
 
 struct PerformTaskContext : Noncopyable {
-    PerformTaskContext(ScriptExecutionContext* scriptExecutionContext, PassOwnPtr<ScriptExecutionContext::Task> task)
-        : scriptExecutionContext(scriptExecutionContext)
+    PerformTaskContext(PassRefPtr<DocumentWeakReference> documentReference, PassOwnPtr<ScriptExecutionContext::Task> task)
+        : documentReference(documentReference)
         , task(task)
     {
     }
 
-    ScriptExecutionContext* scriptExecutionContext; // The context should exist until task execution.
+    RefPtr<DocumentWeakReference> documentReference;
     OwnPtr<ScriptExecutionContext::Task> task;
 };
 
 static void performTask(void* ctx)
 {
-    PerformTaskContext* ptctx = reinterpret_cast<PerformTaskContext*>(ctx);
-    ptctx->task->performTask(ptctx->scriptExecutionContext);
-    delete ptctx;
+    ASSERT(isMainThread());
+
+    PerformTaskContext* context = reinterpret_cast<PerformTaskContext*>(ctx);
+    ASSERT(context);
+
+    if (Document* document = context->documentReference->document())
+        context->task->performTask(document);
+
+    delete context;
 }
 
 void Document::postTask(PassOwnPtr<Task> task)
@@ -4719,7 +4728,7 @@ void Document::postTask(PassOwnPtr<Task> task)
         ScriptExecutionContextTaskTimer* timer = new ScriptExecutionContextTaskTimer(static_cast<Document*>(this), task);
         timer->startOneShot(0);
     } else {
-        callOnMainThread(performTask, new PerformTaskContext(this, task));
+        callOnMainThread(performTask, new PerformTaskContext(m_weakReference, task));
     }
 }
 
@@ -4785,4 +4794,22 @@ InspectorTimelineAgent* Document::inspectorTimelineAgent() const
 }
 #endif
 
+inline DocumentWeakReference::DocumentWeakReference(Document* document)
+    : m_document(document)
+{
+    ASSERT(isMainThread());
+}
+
+inline Document* DocumentWeakReference::document()
+{
+    ASSERT(isMainThread());
+    return m_document;
+}
+
+inline void DocumentWeakReference::clear()
+{
+    ASSERT(isMainThread());
+    m_document = 0;
+}
+
 } // namespace WebCore
diff --git a/WebCore/dom/Document.h b/WebCore/dom/Document.h
index 857aacb..4d17e0b 100644
--- a/WebCore/dom/Document.h
+++ b/WebCore/dom/Document.h
@@ -173,6 +173,19 @@ struct FormElementKeyHashTraits : WTF::GenericHashTraits<FormElementKey> {
     static bool isDeletedValue(const FormElementKey& value) { return value.isHashTableDeletedValue(); }
 };
 
+class DocumentWeakReference : public ThreadSafeShared<DocumentWeakReference> {
+public:
+    static PassRefPtr<DocumentWeakReference> create(Document* document)
+    {
+        return adoptRef(new DocumentWeakReference(document));
+    }
+    Document* document();
+    void clear();
+private:
+    DocumentWeakReference(Document*);
+    Document* m_document;
+};
+
 class Document : public ContainerNode, public ScriptExecutionContext {
 public:
     static PassRefPtr<Document> create(Frame* frame)
@@ -1191,6 +1204,8 @@ private:
 #if ENABLE(WML)
     bool m_containsWMLContent;
 #endif
+
+    RefPtr<DocumentWeakReference> m_weakReference;
 };
 
 inline bool Document::hasElementWithId(AtomicStringImpl* id) const

-- 
WebKit Debian packaging