From 3ad73c2447616b29af150605df326f0bfa9ccfb8 Mon Sep 17 00:00:00 2001
From: "alqahira%ardisson.org"
 <alqahira%ardisson.org@18797224-902f-48f8-a5cc-f745e15eee43>
Date: Sat, 24 Jul 2010 21:39:46 +0000
Subject: [PATCH] Bug 535926, async onload blocker. Patch by Olli Pettay
 <Olli.Pettay@helsinki.fi>, r=bz, sr=sicking, a1.9.0.next=dveditz

git-svn-id: svn://10.0.0.236/trunk@260882 18797224-902f-48f8-a5cc-f745e15eee43
---
 mozilla/content/base/src/nsDocument.cpp | 28 +++++++++++++++++++++++--
 mozilla/content/base/src/nsDocument.h   |  6 ++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/mozilla/content/base/src/nsDocument.cpp b/mozilla/content/base/src/nsDocument.cpp
index 96fe9e0aa83..05e33152623 100644
--- a/mozilla/content/base/src/nsDocument.cpp
+++ b/mozilla/content/base/src/nsDocument.cpp
@@ -5717,12 +5717,31 @@ nsDocument::GetLayoutHistoryState() const
   return state;
 }
 
+void
+nsDocument::AsyncBlockOnload()
+{
+  while (mAsyncOnloadBlockCount) {
+    --mAsyncOnloadBlockCount;
+    BlockOnload();
+  }
+}
+
 void
 nsDocument::BlockOnload()
 {
   // If mScriptGlobalObject is null, we shouldn't be messing with the loadgroup
   // -- it's not ours.
   if (mOnloadBlockCount == 0 && mScriptGlobalObject) {
+    if (!nsContentUtils::IsSafeToRunScript()) {
+      // Because AddRequest may lead to OnStateChange calls in chrome,
+      // block onload only when there are no script blockers.
+      ++mAsyncOnloadBlockCount;
+      if (mAsyncOnloadBlockCount == 1) {
+        nsContentUtils::AddScriptRunner(
+          NS_NEW_RUNNABLE_METHOD(nsDocument, this, AsyncBlockOnload));
+      }
+      return;
+    }
     nsCOMPtr<nsILoadGroup> loadGroup = GetDocumentLoadGroup();
     if (loadGroup) {
       loadGroup->AddRequest(mOnloadBlocker, nsnull);
@@ -5734,7 +5753,7 @@ nsDocument::BlockOnload()
 void
 nsDocument::UnblockOnload(PRBool aFireSync)
 {
-  if (mOnloadBlockCount == 0) {
+  if (mOnloadBlockCount == 0 && mAsyncOnloadBlockCount == 0) {
     NS_NOTREACHED("More UnblockOnload() calls than BlockOnload() calls; dropping call");
     return;
   }
@@ -5744,7 +5763,7 @@ nsDocument::UnblockOnload(PRBool aFireSync)
   // If mScriptGlobalObject is null, we shouldn't be messing with the loadgroup
   // -- it's not ours.
   if (mOnloadBlockCount == 0 && mScriptGlobalObject) {
-    if (aFireSync) {
+    if (aFireSync && mAsyncOnloadBlockCount == 0) {
       // Increment mOnloadBlockCount, since DoUnblockOnload will decrement it
       ++mOnloadBlockCount;
       DoUnblockOnload();
@@ -5793,6 +5812,11 @@ nsDocument::DoUnblockOnload()
     return;
   }
 
+  if (mAsyncOnloadBlockCount != 0) {
+    // We need to wait until the async onload block has been handled.
+    PostUnblockOnloadEvent();
+  }
+
   // If mScriptGlobalObject is null, we shouldn't be messing with the loadgroup
   // -- it's not ours.
   if (mScriptGlobalObject) {
diff --git a/mozilla/content/base/src/nsDocument.h b/mozilla/content/base/src/nsDocument.h
index b772bd7f3f2..57908d435ea 100644
--- a/mozilla/content/base/src/nsDocument.h
+++ b/mozilla/content/base/src/nsDocument.h
@@ -676,6 +676,9 @@ public:
 
   virtual nsISupports* GetCurrentContentSink();
 
+  // Only BlockOnload should call this!
+  void AsyncBlockOnload();
+
 protected:
 
   /**
@@ -860,7 +863,10 @@ private:
   // 2)  We haven't had Destroy() called on us yet.
   nsCOMPtr<nsILayoutHistoryState> mLayoutHistoryState;
 
+  // Currently active onload blockers
   PRUint32 mOnloadBlockCount;
+  // Onload blockers which haven't been activated yet
+  PRUint32 mAsyncOnloadBlockCount;
   nsCOMPtr<nsIRequest> mOnloadBlocker;
   
   // A map from unvisited URI hashes to content elements