commit 22aaf037fe977042ca0989cb07b48913045ede7d
author gavinp@chromium.org <gavinp@chromium.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> Fri Aug 26 13:15:00 2011 +0000
committer gavinp@chromium.org <gavinp@chromium.org@268f45cc-cd09-0410-ab3c-d52691b4dbfc> Fri Aug 26 13:15:00 2011 +0000
tree b03f6cbb16c7f8911be42fbc3ce59cbe91e9528d
parent 7eeb5d329df9bbaa4fda64ac8f5f93a8e54e6d82

add a state enumeration to track down cause of null CachedScript execution
https://bugs.webkit.org/show_bug.cgi?id=66939

Reviewed by Alexey Proskuryakov.

Over in http://code.google.com/p/chromium/issues/detail?id=75604 I
have a bug I cannot reproduce.  I added an earlier crash in
https://bugs.webkit.org/show_bug.cgi?id=65563 , and we've since
gotten many good stacks, all coming in through a failed request that
eventually calls notifyFinished() on a ScriptElement with a NULL
m_cachedScript.

I'd like to know how this got NULL.  This enumeration should let
me find that in stack dumps from reproductions.

No new tests, as my goal here is to get telemetry on a bug that I cannot reproduce.

* dom/ScriptElement.cpp:
(WebCore::ScriptElement::ScriptElement):
(WebCore::ScriptElement::requestScript):
(WebCore::ScriptElement::stopLoadRequest):
(WebCore::ScriptElement::notifyFinished):
* dom/ScriptElement.h:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@93871 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/dom/ScriptElement.cpp

diff --git a/Source/WebCore/dom/ScriptElement.cpp b/Source/WebCore/dom/ScriptElement.cpp
index 1f8c858..29e7de0 100644
--- a/Source/WebCore/dom/ScriptElement.cpp
+++ b/Source/WebCore/dom/ScriptElement.cpp
@@ -64,6 +64,7 @@
     , m_willExecuteWhenDocumentFinishedParsing(false)
     , m_forceAsync(!parserInserted)
     , m_willExecuteInOrder(false)
+    , m_cachedScriptState(NeverSet)
 {
     ASSERT(m_element);
 }
@@ -258,8 +259,11 @@
     m_cachedScript = m_element->document()->cachedResourceLoader()->requestScript(request, scriptCharset());
     m_isExternalScript = true;
 
-    if (m_cachedScript)
+    if (m_cachedScript) {
+        ASSERT(m_cachedScriptState == NeverSet);
+        m_cachedScriptState = Set;
         return true;
+    }
 
     dispatchErrorEvent();
     return false;
@@ -295,6 +299,8 @@
     if (m_cachedScript) {
         if (!m_willBeParserExecuted)
             m_cachedScript->removeClient(this);
+        ASSERT(m_cachedScriptState == Set);
+        m_cachedScriptState = ZeroedInStopLoadRequest;
         m_cachedScript = 0;
     }
 }
@@ -320,6 +326,9 @@
         m_element->document()->scriptRunner()->notifyInOrderScriptReady();
     else
         m_element->document()->scriptRunner()->queueScriptForExecution(this, m_cachedScript, ScriptRunner::ASYNC_EXECUTION);
+
+    ASSERT(m_cachedScriptState == Set);
+    m_cachedScriptState = ZeroedInNotifyFinished;
     m_cachedScript = 0;
 }