1/* 2 * Copyright (C) 2010 Google, Inc. All Rights Reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#include "config.h" 27#include "HTMLParserScheduler.h" 28 29#include "Document.h" 30#include "FrameView.h" 31#include "HTMLDocumentParser.h" 32#include "Page.h" 33 34// defaultParserChunkSize is used to define how many tokens the parser will 35// process before checking against parserTimeLimit and possibly yielding. 36// This is a performance optimization to prevent checking after every token. 37static const int defaultParserChunkSize = 4096; 38 39// defaultParserTimeLimit is the seconds the parser will run in one write() call 40// before yielding. Inline <script> execution can cause it to exceed the limit. 41// FIXME: We would like this value to be 0.2. 42static const double defaultParserTimeLimit = 0.500; 43 44namespace WebCore { 45 46static double parserTimeLimit(Page* page) 47{ 48 // We're using the poorly named customHTMLTokenizerTimeDelay setting. 49 if (page && page->hasCustomHTMLTokenizerTimeDelay()) 50 return page->customHTMLTokenizerTimeDelay(); 51 return defaultParserTimeLimit; 52} 53 54static int parserChunkSize(Page* page) 55{ 56 // FIXME: We may need to divide the value from customHTMLTokenizerChunkSize 57 // by some constant to translate from the "character" based behavior of the 58 // old LegacyHTMLDocumentParser to the token-based behavior of this parser. 59 if (page && page->hasCustomHTMLTokenizerChunkSize()) 60 return page->customHTMLTokenizerChunkSize(); 61 return defaultParserChunkSize; 62} 63 64ActiveParserSession::ActiveParserSession(Document* document) 65 : m_document(document) 66{ 67 if (!m_document) 68 return; 69 m_document->incrementActiveParserCount(); 70} 71 72ActiveParserSession::~ActiveParserSession() 73{ 74 if (!m_document) 75 return; 76 m_document->decrementActiveParserCount(); 77} 78 79PumpSession::PumpSession(unsigned& nestingLevel, Document* document) 80 : NestingLevelIncrementer(nestingLevel) 81 , ActiveParserSession(document) 82 // Setting processedTokens to INT_MAX causes us to check for yields 83 // after any token during any parse where yielding is allowed. 84 // At that time we'll initialize startTime. 85 , processedTokens(INT_MAX) 86 , startTime(0) 87 , needsYield(false) 88 , didSeeScript(false) 89{ 90} 91 92PumpSession::~PumpSession() 93{ 94} 95 96HTMLParserScheduler::HTMLParserScheduler(HTMLDocumentParser* parser) 97 : m_parser(parser) 98 , m_parserTimeLimit(parserTimeLimit(m_parser->document()->page())) 99 , m_parserChunkSize(parserChunkSize(m_parser->document()->page())) 100 , m_continueNextChunkTimer(this, &HTMLParserScheduler::continueNextChunkTimerFired) 101 , m_isSuspendedWithActiveTimer(false) 102{ 103} 104 105HTMLParserScheduler::~HTMLParserScheduler() 106{ 107 m_continueNextChunkTimer.stop(); 108} 109 110void HTMLParserScheduler::continueNextChunkTimerFired(Timer<HTMLParserScheduler>* timer) 111{ 112 ASSERT_UNUSED(timer, timer == &m_continueNextChunkTimer); 113 // FIXME: The timer class should handle timer priorities instead of this code. 114 // If a layout is scheduled, wait again to let the layout timer run first. 115 if (m_parser->document()->isLayoutTimerActive()) { 116 m_continueNextChunkTimer.startOneShot(0); 117 return; 118 } 119 m_parser->resumeParsingAfterYield(); 120} 121 122void HTMLParserScheduler::checkForYieldBeforeScript(PumpSession& session) 123{ 124 // If we've never painted before and a layout is pending, yield prior to running 125 // scripts to give the page a chance to paint earlier. 126 Document* document = m_parser->document(); 127 bool needsFirstPaint = document->view() && !document->view()->hasEverPainted(); 128 if (needsFirstPaint && document->isLayoutTimerActive()) 129 session.needsYield = true; 130 session.didSeeScript = true; 131} 132 133void HTMLParserScheduler::scheduleForResume() 134{ 135 m_continueNextChunkTimer.startOneShot(0); 136} 137 138 139void HTMLParserScheduler::suspend() 140{ 141 ASSERT(!m_isSuspendedWithActiveTimer); 142 if (!m_continueNextChunkTimer.isActive()) 143 return; 144 m_isSuspendedWithActiveTimer = true; 145 m_continueNextChunkTimer.stop(); 146} 147 148void HTMLParserScheduler::resume() 149{ 150 ASSERT(!m_continueNextChunkTimer.isActive()); 151 if (!m_isSuspendedWithActiveTimer) 152 return; 153 m_isSuspendedWithActiveTimer = false; 154 m_continueNextChunkTimer.startOneShot(0); 155} 156 157} 158