Properly suspend HTMLDocumentParser

Source/core/html/parser/HTMLDocumentParser.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 98 matching lines @@
     , m_tokenizer(nullptr)
     , m_scriptRunner(HTMLScriptRunner::create(&document, this))
     , m_treeBuilder(HTMLTreeBuilder::create(this, &document, parserContentPolicy(), reportErrors, m_options))
     , m_parserScheduler(HTMLParserScheduler::create(this))
     , m_xssAuditorDelegate(&document)
     , m_weakFactory(this)
     , m_preloader(HTMLResourcePreloader::create(document))
     , m_isPinnedToMainThread(false)
     , m_endWasDelayed(false)
     , m_haveBackgroundParser(false)
+    , m_tasksWereSuspended(false)
     , m_pumpSessionNestingLevel(0)
     , m_pumpSpeculationsSessionNestingLevel(0)
 {
     ASSERT(shouldUseThreading() || (m_token && m_tokenizer));
 }
 
 // FIXME: Member variables should be grouped into self-initializing structs to
 // minimize code duplication between these constructors.
 HTMLDocumentParser::HTMLDocumentParser(DocumentFragment* fragment, Element* contextElement, ParserContentPolicy parserContentPolicy)
     : ScriptableDocumentParser(fragment->document(), parserContentPolicy)
     , m_options(&fragment->document())
     , m_token(adoptPtr(new HTMLToken))
     , m_tokenizer(HTMLTokenizer::create(m_options))
     , m_treeBuilder(HTMLTreeBuilder::create(this, fragment, contextElement, this->parserContentPolicy(), m_options))
     , m_xssAuditorDelegate(&fragment->document())
     , m_weakFactory(this)
     , m_isPinnedToMainThread(true)
     , m_endWasDelayed(false)
     , m_haveBackgroundParser(false)
+    , m_tasksWereSuspended(false)
     , m_pumpSessionNestingLevel(0)
     , m_pumpSpeculationsSessionNestingLevel(0)
 {
     ASSERT(!shouldUseThreading());
     bool reportErrors = false; // For now document fragment parsing never reports errors.
     m_tokenizer->setState(tokenizerStateForContextElement(contextElement, reportErrors, m_options));
     m_xssAuditor.initForFragment();
 }
 
 HTMLDocumentParser::~HTMLDocumentParser()
@@ skipping 174 matching lines @@
     return true;
 }
 
 void HTMLDocumentParser::didReceiveParsedChunkFromBackgroundParser(PassOwnPtr<ParsedChunk> chunk)
 {
     TRACE_EVENT0("blink", "HTMLDocumentParser::didReceiveParsedChunkFromBackgroundParser");
 
     // alert(), runModalDialog, and the JavaScript Debugger all run nested event loops
     // which can cause this method to be re-entered. We detect re-entry using
     // hasActiveParser(), save the chunk as a speculation, and return.
-    if (isWaitingForScripts() || !m_speculations.isEmpty() || document()->activeParserCount() > 0) {
+    if (isWaitingForScripts() || !m_speculations.isEmpty() || document()->activeParserCount() > 0 || m_tasksWereSuspended || isScheduledForResume()) {
+        if (m_tasksWereSuspended)
+            m_parserScheduler->forceResumeAfterYield();
         m_preloader->takeAndPreload(chunk->preloads);
         m_speculations.append(chunk);
         return;
     }
 
     // processParsedChunkFromBackgroundParser can cause this parser to be detached from the Document,
     // but we need to ensure it isn't deleted yet.
     RefPtrWillBeRawPtr<HTMLDocumentParser> protect(this);
 
     ASSERT(m_speculations.isEmpty());
@@ skipping 662 matching lines @@
 {
     RefPtrWillBeRawPtr<HTMLDocumentParser> parser = HTMLDocumentParser::create(fragment, contextElement, parserContentPolicy);
     parser->insert(source); // Use insert() so that the parser will not yield.
     parser->finish();
     ASSERT(!parser->processingData()); // Make sure we're done. <rdar://problem/3963151>
     parser->detach(); // Allows ~DocumentParser to assert it was detached before destruction.
 }
 
 void HTMLDocumentParser::suspendScheduledTasks()
 {
+    ASSERT(!m_tasksWereSuspended);
+    m_tasksWereSuspended = true;
     if (m_parserScheduler)
         m_parserScheduler->suspend();
 }
 
 void HTMLDocumentParser::resumeScheduledTasks()
 {
+    ASSERT(m_tasksWereSuspended);
+    m_tasksWereSuspended = false;
     if (m_parserScheduler)
         m_parserScheduler->resume();
 }
 
 void HTMLDocumentParser::appendBytes(const char* data, size_t length)
 {
     if (!length || isStopped())
         return;
 
     if (shouldUseThreading()) {
@@ skipping 26 matching lines @@
 void HTMLDocumentParser::setDecoder(PassOwnPtr<TextResourceDecoder> decoder)
 {
     ASSERT(decoder);
     DecodedDataDocumentParser::setDecoder(decoder);
 
     if (m_haveBackgroundParser)
         HTMLParserThread::shared()->postTask(bind(&BackgroundHTMLParser::setDecoder, m_backgroundParser, takeDecoder()));
 }
 
 }