Bug 453801. Make sure to not fire onload before deferred scripts have executed. r+sr=sicking

content/base/src/nsScriptLoader.cpp

@@ -123,7 +123,9 @@ NS_IMPL_THREADSAFE_ISUPPORTS0(nsScriptLoadRequest)
 nsScriptLoader::nsScriptLoader(nsIDocument *aDocument)
   : mDocument(aDocument),
     mBlockerCount(0),
-    mEnabled(PR_TRUE)
+    mEnabled(PR_TRUE),
+    mDeferEnabled(PR_FALSE),
+    mUnblockOnloadWhenDoneProcessing(PR_FALSE)
 {
 }
 
@@ -711,6 +713,15 @@ nsScriptLoader::ProcessPendingRequests()
     mPendingChildLoaders.RemoveElementAt(0);
     child->RemoveExecuteBlocker();
   }
+
+  if (mUnblockOnloadWhenDoneProcessing && mDocument &&
+      !GetFirstPendingRequest()) {
+    // No more pending scripts; time to unblock onload.
+    // OK to unblock onload synchronously here, since callers must be
+    // prepared for the world changing anyway.
+    mUnblockOnloadWhenDoneProcessing = PR_FALSE;
+    mDocument->UnblockOnload(PR_TRUE);
+  }
 }
 
 PRBool
@@ -988,6 +999,11 @@ nsScriptLoader::ShouldExecuteScript(nsIDocument* aDocument,
 void
 nsScriptLoader::EndDeferringScripts()
 {
+  if (mDeferEnabled) {
+    // Have to check because we apparently get EndDeferringScripts
+    // without BeginDeferringScripts in some cases
+    mUnblockOnloadWhenDoneProcessing = PR_TRUE;
+  }
   mDeferEnabled = PR_FALSE;
   for (PRUint32 i = 0; i < (PRUint32)mRequests.Count(); ++i) {
     mRequests[i]->mDefer = PR_FALSE;

content/base/src/nsScriptLoader.h

@@ -194,6 +194,9 @@ public:
   void BeginDeferringScripts()
   {
     mDeferEnabled = PR_TRUE;
+    if (mDocument) {
+      mDocument->BlockOnload();
+    }
   }
 
   /**
@@ -229,9 +232,11 @@ protected:
   nsresult StartLoad(nsScriptLoadRequest *aRequest, const nsAString &aType);
 
   /**
-   * Process any pending requests asyncronously (i.e. off an event) if there
+   * Process any pending requests asynchronously (i.e. off an event) if there
    * are any. Note that this is a no-op if there aren't any currently pending
    * requests.
+   *
+   * This function is virtual to allow cross-library calls to SetEnabled()
    */
   virtual void ProcessPendingRequestsAsync();
 
@@ -300,6 +305,7 @@ protected:
   PRUint32 mBlockerCount;
   PRPackedBool mEnabled;
   PRPackedBool mDeferEnabled;
+  PRPackedBool mUnblockOnloadWhenDoneProcessing;
 };
 
 #endif //__nsScriptLoader_h__