Add a document api to prevent onload from firing too early. Bug 293818,

r=darin, sr=jst, a=asa


git-svn-id: svn://10.0.0.236/trunk@173388 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/content/base/public/nsIDocument.h

@@ -90,8 +90,8 @@ class nsILayoutHistoryState;
 
 // IID for the nsIDocument interface
 #define NS_IDOCUMENT_IID      \
-{ 0x5cb398a4, 0xbd6f, 0x4af5, \
- { 0x81, 0x56, 0x59, 0xfd, 0xcf, 0xe6, 0xab, 0x45 } }
+{ 0x660e9925, 0x30e0, 0x4016, \
+ { 0x8b, 0x7f, 0x0d, 0x70, 0x6e, 0xba, 0xc9, 0x8e } }
 
 // The base value for the content ID counter.
 // This counter is used by the document to 
@@ -713,6 +713,17 @@ public:
    */
   virtual already_AddRefed<nsILayoutHistoryState> GetLayoutHistoryState() const = 0;
 
+  /**
+   * Methods that can be used to prevent onload firing while an event that
+   * should block onload is posted.  onload is guaranteed to not fire until
+   * either all calls to BlockOnload() have been matched by calls to
+   * UnblockOnload() or the load has been stopped altogether (by the user
+   * pressing the Stop button, say).  onload may fire synchronously from inside
+   * the UnblockOnload() call.
+   */
+  virtual void BlockOnload() = 0;
+  virtual void UnblockOnload() = 0;
+
 protected:
   ~nsIDocument()
   {

mozilla/content/base/src/nsDocument.cpp

@@ -277,6 +277,72 @@ nsDOMStyleSheetList::StyleSheetRemoved(nsIDocument *aDocument,
   }
 }
 
+// nsOnloadBlocker implementation
+NS_IMPL_ISUPPORTS1(nsOnloadBlocker, nsIRequest)
+
+NS_IMETHODIMP
+nsOnloadBlocker::GetName(nsACString &aResult)
+{ 
+  aResult.AssignLiteral("about:document-onload-blocker");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsOnloadBlocker::IsPending(PRBool *_retval)
+{
+  *_retval = PR_TRUE;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsOnloadBlocker::GetStatus(nsresult *status)
+{
+  *status = NS_OK;
+  return NS_OK;
+} 
+
+NS_IMETHODIMP
+nsOnloadBlocker::Cancel(nsresult status)
+{
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsOnloadBlocker::Suspend(void)
+{
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsOnloadBlocker::Resume(void)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsOnloadBlocker::GetLoadGroup(nsILoadGroup * *aLoadGroup)
+{
+  *aLoadGroup = nsnull;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsOnloadBlocker::SetLoadGroup(nsILoadGroup * aLoadGroup)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsOnloadBlocker::GetLoadFlags(nsLoadFlags *aLoadFlags)
+{
+  *aLoadFlags = nsIRequest::LOAD_NORMAL;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsOnloadBlocker::SetLoadFlags(nsLoadFlags aLoadFlags)
+{
+  return NS_OK;
+}
+
 
 class nsDOMImplementation : public nsIDOMDOMImplementation,
                             public nsIPrivateDOMImplementation
@@ -684,6 +750,9 @@ nsDocument::Init()
   // (static cast to the correct interface pointer)
   mObservers.InsertElementAt(NS_STATIC_CAST(nsIDocumentObserver*, bindingManager), 0);
 
+  mOnloadBlocker = new nsOnloadBlocker();
+  NS_ENSURE_TRUE(mOnloadBlocker, NS_ERROR_OUT_OF_MEMORY);
+  
   NS_NewCSSLoader(this, &mCSSLoader);
   NS_ENSURE_TRUE(mCSSLoader, NS_ERROR_OUT_OF_MEMORY);
   // Assume we're not HTML and not quirky, until we know otherwise
@@ -4808,3 +4877,32 @@ nsDocument::GetLayoutHistoryState() const
 
   return state;
 }
+
+void
+nsDocument::BlockOnload()
+{
+  if (mOnloadBlockCount == 0) {
+    nsCOMPtr<nsILoadGroup> loadGroup = GetDocumentLoadGroup();
+    if (loadGroup) {
+      loadGroup->AddRequest(mOnloadBlocker, nsnull);
+    }
+  }
+  ++mOnloadBlockCount;      
+}
+
+void
+nsDocument::UnblockOnload()
+{
+  if (mOnloadBlockCount == 0) {
+    return;
+  }
+
+  --mOnloadBlockCount;
+
+  if (mOnloadBlockCount == 0) {
+    nsCOMPtr<nsILoadGroup> loadGroup = GetDocumentLoadGroup();
+    if (loadGroup) {
+      loadGroup->RemoveRequest(mOnloadBlocker, nsnull, NS_OK);
+    }
+  }    
+}

mozilla/content/base/src/nsDocument.h

@@ -81,6 +81,8 @@
 #include "nsIRadioGroupContainer.h"
 #include "nsIScriptEventManager.h"
 #include "nsILayoutHistoryState.h"
+#include "nsIRequest.h"
+#include "nsILoadGroup.h"
 
 // Put these here so all document impls get them automatically
 #include "nsHTMLStyleSheet.h"
@@ -106,6 +108,7 @@ class nsXPathDocumentTearoff;
 class nsIRadioVisitor;
 class nsIFormControl;
 struct nsRadioGroupStruct;
+class nsOnloadBlocker;
 
 
 class nsDocHeaderData
@@ -172,6 +175,17 @@ protected:
   void*         mScriptObject;
 };
 
+class nsOnloadBlocker : public nsIRequest
+{
+public:
+  nsOnloadBlocker() {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIREQUEST
+
+private:
+  ~nsOnloadBlocker() {}
+};
 
 // Base class for our document implementations.
 //
@@ -540,6 +554,9 @@ public:
   virtual NS_HIDDEN_(void) Destroy();
   virtual NS_HIDDEN_(already_AddRefed<nsILayoutHistoryState>) GetLayoutHistoryState() const;
 
+  virtual NS_HIDDEN_(void) BlockOnload();
+  virtual NS_HIDDEN_(void) UnblockOnload();
+
 protected:
 
   void RetrieveRelevantHeaders(nsIChannel *aChannel);
@@ -636,6 +653,9 @@ private:
   // 1)  We have no script global object.
   // 2)  We haven't had Destroy() called on us yet.
   nsCOMPtr<nsILayoutHistoryState> mLayoutHistoryState;
+
+  PRUint32 mOnloadBlockCount;
+  nsCOMPtr<nsIRequest> mOnloadBlocker;
 };
 
 

mozilla/content/base/src/nsImageLoadingContent.cpp

@@ -604,17 +604,15 @@ nsImageLoadingContent::StringToURI(const nsAString& aSpec,
  */
 MOZ_DECL_CTOR_COUNTER(ImageEvent)
 
-class ImageEvent : public PLEvent,
-                   public nsDummyLayoutRequest
+class ImageEvent : public PLEvent
 {
 public:
   ImageEvent(nsPresContext* aPresContext, nsIContent* aContent,
-             const nsAString& aMessage, nsILoadGroup *aLoadGroup)
-    : nsDummyLayoutRequest(nsnull),
-      mPresContext(aPresContext),
+             const nsAString& aMessage, nsIDocument* aDocument)
+    : mPresContext(aPresContext),
       mContent(aContent),
       mMessage(aMessage),
-      mLoadGroup(aLoadGroup)
+      mDocument(aDocument)
   {
     MOZ_COUNT_CTOR(ImageEvent);
   }
@@ -626,7 +624,10 @@ public:
   nsCOMPtr<nsPresContext> mPresContext;
   nsCOMPtr<nsIContent> mContent;
   nsString mMessage;
-  nsCOMPtr<nsILoadGroup> mLoadGroup;
+  // Need to hold on to the document in case our event outlives document
+  // teardown... Wantto be able to get back to the document even if the
+  // prescontext and content can't.
+  nsCOMPtr<nsIDocument> mDocument;
 };
 
 PR_STATIC_CALLBACK(void*)
@@ -646,8 +647,6 @@ HandleImagePLEvent(PLEvent* aEvent)
   evt->mContent->HandleDOMEvent(evt->mPresContext, &event, nsnull,
                                 NS_EVENT_FLAG_INIT, &estatus);
 
-  evt->mLoadGroup->RemoveRequest(evt, nsnull, NS_OK);
-
   return nsnull;
 }
 
@@ -655,12 +654,9 @@ PR_STATIC_CALLBACK(void)
 DestroyImagePLEvent(PLEvent* aEvent)
 {
   ImageEvent* evt = NS_STATIC_CAST(ImageEvent*, aEvent);
+  evt->mDocument->UnblockOnload();
 
-  // We're reference counted, and we hold a strong reference to
-  // ourselves while we're a 'live' PLEvent. Now that the PLEvent is
-  // destroyed, release ourselves.
-
-  NS_RELEASE(evt);
+  delete evt;
 }
 
 nsresult
@@ -687,8 +683,6 @@ nsImageLoadingContent::FireEvent(const nsAString& aEventType)
                                            getter_AddRefs(eventQ));
   NS_ENSURE_TRUE(eventQ, rv);
 
-  nsCOMPtr<nsILoadGroup> loadGroup = document->GetDocumentLoadGroup();
-
   nsIPresShell *shell = document->GetShellAt(0);
   NS_ENSURE_TRUE(shell, NS_ERROR_FAILURE);
 
@@ -697,25 +691,19 @@ nsImageLoadingContent::FireEvent(const nsAString& aEventType)
 
   nsCOMPtr<nsIContent> ourContent = do_QueryInterface(this);
   
-  ImageEvent* evt = new ImageEvent(presContext, ourContent, aEventType,
-                                   loadGroup);
+  ImageEvent* evt = new ImageEvent(presContext, ourContent, aEventType, document);
 
   NS_ENSURE_TRUE(evt, NS_ERROR_OUT_OF_MEMORY);
 
   PL_InitEvent(evt, this, ::HandleImagePLEvent, ::DestroyImagePLEvent);
 
-  // The event will own itself while it's in the event queue, once
-  // removed, it will release itself, and if there are no other
-  // references, it will be deleted.
-  NS_ADDREF(evt);
-
+  // Block onload for our event.  Since we unblock in the event destructor, we
+  // want to block now, even if posting will fail.
+  document->BlockOnload();
+  
   rv = eventQ->PostEvent(evt);
 
-  if (NS_SUCCEEDED(rv)) {
-    // Add the dummy request (the ImageEvent) to the load group only
-    // after all the early returns here!
-    loadGroup->AddRequest(evt, nsnull);
-  } else {
+  if (NS_FAILED(rv)) {
     PL_DestroyEvent(evt);
   }