Oilpan: have PendingScripts trace their script elements.

Source/core/html/parser/HTMLScriptRunner.cpp

 /*
  * Copyright (C) 2010 Google, Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 36 matching lines @@
     : m_document(document)
     , m_host(host)
     , m_scriptNestingLevel(0)
     , m_hasScriptsWaitingForResources(false)
 {
     ASSERT(m_host);
 }
 
 HTMLScriptRunner::~HTMLScriptRunner()
 {
-    // FIXME: Should we be passed a "done loading/parsing" callback sooner than destruction?
+#if ENABLE(OILPAN)
+    // If the document is destructed without having explicitly
+    // detached the parser (and this script runner object), perform
+    // detach steps now. This will happen if the Document, the parser
+    // and this script runner object are swept out in the same GC.
+    detach();
+#else
+    // Verify that detach() has been called.
+    ASSERT(!m_document);
+#endif
+}
+
+void HTMLScriptRunner::detach()
+{
+    if (!m_document)
+        return;
+
     if (m_parserBlockingScript.resource() && m_parserBlockingScript.watchingForLoad())
         stopWatchingForLoad(m_parserBlockingScript);
 
     while (!m_scriptsToExecuteAfterParsing.isEmpty()) {
         PendingScript pendingScript = m_scriptsToExecuteAfterParsing.takeFirst();
         if (pendingScript.resource() && pendingScript.watchingForLoad())
             stopWatchingForLoad(pendingScript);
     }
-}
-
-void HTMLScriptRunner::detach()
-{
-    m_document = 0;
+    m_document = nullptr;
 }
 
 static KURL documentURLForScriptExecution(Document* document)
 {
     if (!document)
         return KURL();
 
     if (!document->frame()) {
         if (document->importsController())
             return document->url();
@@ skipping 54 matching lines @@
         Microtask::performCheckpoint();
         if (pendingScriptType == PendingScriptBlockingParser) {
             m_hasScriptsWaitingForResources = !m_document->isScriptExecutionReady();
             // The parser cannot be unblocked as a microtask requested another resource
             if (m_hasScriptsWaitingForResources)
                 return;
         }
     }
 
     // Clear the pending script before possible rentrancy from executeScript()
-    RefPtr<Element> element = pendingScript.releaseElementAndClear();
+    RefPtrWillBeRawPtr<Element> element = pendingScript.releaseElementAndClear();
     if (ScriptLoader* scriptLoader = toScriptLoaderIfPossible(element.get())) {
         NestingLevelIncrementer nestingLevelIncrementer(m_scriptNestingLevel);
         IgnoreDestructiveWriteCountIncrementer ignoreDestructiveWriteCountIncrementer(m_document);
         if (errorOccurred)
             scriptLoader->dispatchErrorEvent();
         else {
             ASSERT(isExecutingScript());
             scriptLoader->executeScript(sourceCode);
             element->dispatchEvent(createScriptLoadEvent());
         }
     }
     ASSERT(!isExecutingScript());
 }
 
 void HTMLScriptRunner::watchForLoad(PendingScript& pendingScript)
 {
     ASSERT(!pendingScript.watchingForLoad());
-    m_host->watchForLoad(pendingScript.resource());
+    ASSERT(!pendingScript.resource()->isLoaded());
+    // addClient() will call notifyFinished() if the load is complete.
+    // Callers do not expect to be re-entered from this call, so they
+    // should not become a client of an already-loaded Resource.
+    pendingScript.resource()->addClient(this);
     pendingScript.setWatchingForLoad(true);
 }
 
 void HTMLScriptRunner::stopWatchingForLoad(PendingScript& pendingScript)
 {
     ASSERT(pendingScript.watchingForLoad());
-    m_host->stopWatchingForLoad(pendingScript.resource());
+    pendingScript.resource()->removeClient(this);
     pendingScript.setWatchingForLoad(false);
 }
 
+void HTMLScriptRunner::notifyFinished(Resource* cachedResource)
+{
+    m_host->notifyScriptLoaded(cachedResource);
+}
+
 // Implements the steps for 'An end tag whose tag name is "script"'
 // http://whatwg.org/html#scriptEndTag
 // Script handling lives outside the tree builder to keep each class simple.
-void HTMLScriptRunner::execute(PassRefPtr<Element> scriptElement, const TextPosition& scriptStartPosition)
+void HTMLScriptRunner::execute(PassRefPtrWillBeRawPtr<Element> scriptElement, const TextPosition& scriptStartPosition)
 {
     ASSERT(scriptElement);
     // FIXME: If scripting is disabled, always just return.
 
     bool hadPreloadScanner = m_host->hasPreloadScanner();
 
     // Try to execute the script given to us.
     runScript(scriptElement.get(), scriptStartPosition);
 
     if (hasParserBlockingScript()) {
@@ skipping 133 matching lines @@
             } else {
                 ScriptSourceCode sourceCode(script->textContent(), documentURLForScriptExecution(m_document), scriptStartPosition);
                 scriptLoader->executeScript(sourceCode);
             }
         } else {
             requestParsingBlockingScript(script);
         }
     }
 }
 
+void HTMLScriptRunner::trace(Visitor* visitor)
+{
+    visitor->trace(m_document);
+    visitor->trace(m_host);
+    visitor->trace(m_parserBlockingScript);
+    visitor->trace(m_scriptsToExecuteAfterParsing);
 }
+
+}