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 #ifndef HTMLParserScheduler_h 27 #define HTMLParserScheduler_h 28 29 #include <limits.h> 30 31 #include "NestingLevelIncrementer.h" 32 #include "Timer.h" 33 #include <wtf/CurrentTime.h> 34 #include <wtf/PassOwnPtr.h> 35 36 namespace WebCore { 37 38 class HTMLDocumentParser; 39 40 class PumpSession : public NestingLevelIncrementer { 41 public: PumpSession(unsigned & nestingLevel)42 PumpSession(unsigned& nestingLevel) 43 : NestingLevelIncrementer(nestingLevel) 44 // Setting processedTokens to INT_MAX causes us to check for yields 45 // after any token during any parse where yielding is allowed. 46 // At that time we'll initialize startTime. 47 , processedTokens(INT_MAX) 48 , startTime(0) 49 , needsYield(false) 50 { 51 } 52 53 int processedTokens; 54 double startTime; 55 bool needsYield; 56 }; 57 58 class HTMLParserScheduler { 59 WTF_MAKE_NONCOPYABLE(HTMLParserScheduler); WTF_MAKE_FAST_ALLOCATED; 60 public: create(HTMLDocumentParser * parser)61 static PassOwnPtr<HTMLParserScheduler> create(HTMLDocumentParser* parser) 62 { 63 return adoptPtr(new HTMLParserScheduler(parser)); 64 } 65 ~HTMLParserScheduler(); 66 67 // Inline as this is called after every token in the parser. checkForYieldBeforeToken(PumpSession & session)68 void checkForYieldBeforeToken(PumpSession& session) 69 { 70 if (session.processedTokens > m_parserChunkSize) { 71 // currentTime() can be expensive. By delaying, we avoided calling 72 // currentTime() when constructing non-yielding PumpSessions. 73 if (!session.startTime) 74 session.startTime = currentTime(); 75 76 session.processedTokens = 0; 77 double elapsedTime = currentTime() - session.startTime; 78 if (elapsedTime > m_parserTimeLimit) 79 session.needsYield = true; 80 } 81 ++session.processedTokens; 82 } 83 void checkForYieldBeforeScript(PumpSession&); 84 85 void scheduleForResume(); isScheduledForResume()86 bool isScheduledForResume() const { return m_isSuspendedWithActiveTimer || m_continueNextChunkTimer.isActive(); } 87 88 void suspend(); 89 void resume(); 90 91 private: 92 HTMLParserScheduler(HTMLDocumentParser*); 93 94 void continueNextChunkTimerFired(Timer<HTMLParserScheduler>*); 95 96 HTMLDocumentParser* m_parser; 97 98 double m_parserTimeLimit; 99 int m_parserChunkSize; 100 Timer<HTMLParserScheduler> m_continueNextChunkTimer; 101 bool m_isSuspendedWithActiveTimer; 102 }; 103 104 } 105 106 #endif 107