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 "FrameView.h" // Only for isLayoutTimerActive
30 #include "HTMLDocumentParser.h"
31 #include "Document.h"
32
33 // defaultParserChunkSize is used to define how many tokens the parser will
34 // process before checking against parserTimeLimit and possibly yielding.
35 // This is a performance optimization to prevent checking after every token.
36 static const int defaultParserChunkSize = 4096;
37
38 // defaultParserTimeLimit is the seconds the parser will run in one write() call
39 // before yielding. Inline <script> execution can cause it to excede the limit.
40 // FIXME: We would like this value to be 0.2.
41 static const double defaultParserTimeLimit = 0.500;
42
43 namespace WebCore {
44
parserTimeLimit(Page * page)45 static double parserTimeLimit(Page* page)
46 {
47 // We're using the poorly named customHTMLTokenizerTimeDelay setting.
48 if (page && page->hasCustomHTMLTokenizerTimeDelay())
49 return page->customHTMLTokenizerTimeDelay();
50 return defaultParserTimeLimit;
51 }
52
parserChunkSize(Page * page)53 static int parserChunkSize(Page* page)
54 {
55 // FIXME: We may need to divide the value from customHTMLTokenizerChunkSize
56 // by some constant to translate from the "character" based behavior of the
57 // old LegacyHTMLDocumentParser to the token-based behavior of this parser.
58 if (page && page->hasCustomHTMLTokenizerChunkSize())
59 return page->customHTMLTokenizerChunkSize();
60 return defaultParserChunkSize;
61 }
62
HTMLParserScheduler(HTMLDocumentParser * parser)63 HTMLParserScheduler::HTMLParserScheduler(HTMLDocumentParser* parser)
64 : m_parser(parser)
65 , m_parserTimeLimit(parserTimeLimit(m_parser->document()->page()))
66 , m_parserChunkSize(parserChunkSize(m_parser->document()->page()))
67 , m_continueNextChunkTimer(this, &HTMLParserScheduler::continueNextChunkTimerFired)
68 , m_isSuspendedWithActiveTimer(false)
69 {
70 }
71
~HTMLParserScheduler()72 HTMLParserScheduler::~HTMLParserScheduler()
73 {
74 m_continueNextChunkTimer.stop();
75 }
76
continueNextChunkTimerFired(Timer<HTMLParserScheduler> * timer)77 void HTMLParserScheduler::continueNextChunkTimerFired(Timer<HTMLParserScheduler>* timer)
78 {
79 ASSERT_UNUSED(timer, timer == &m_continueNextChunkTimer);
80 // FIXME: The timer class should handle timer priorities instead of this code.
81 // If a layout is scheduled, wait again to let the layout timer run first.
82 if (m_parser->document()->isLayoutTimerActive()) {
83 m_continueNextChunkTimer.startOneShot(0);
84 return;
85 }
86 m_parser->resumeParsingAfterYield();
87 }
88
checkForYieldBeforeScript(PumpSession & session)89 void HTMLParserScheduler::checkForYieldBeforeScript(PumpSession& session)
90 {
91 // If we've never painted before and a layout is pending, yield prior to running
92 // scripts to give the page a chance to paint earlier.
93 Document* document = m_parser->document();
94 bool needsFirstPaint = document->view() && !document->view()->hasEverPainted();
95 if (needsFirstPaint && document->isLayoutTimerActive())
96 session.needsYield = true;
97 }
98
scheduleForResume()99 void HTMLParserScheduler::scheduleForResume()
100 {
101 m_continueNextChunkTimer.startOneShot(0);
102 }
103
104
suspend()105 void HTMLParserScheduler::suspend()
106 {
107 ASSERT(!m_isSuspendedWithActiveTimer);
108 if (!m_continueNextChunkTimer.isActive())
109 return;
110 m_isSuspendedWithActiveTimer = true;
111 m_continueNextChunkTimer.stop();
112 }
113
resume()114 void HTMLParserScheduler::resume()
115 {
116 ASSERT(!m_continueNextChunkTimer.isActive());
117 if (!m_isSuspendedWithActiveTimer)
118 return;
119 m_isSuspendedWithActiveTimer = false;
120 m_continueNextChunkTimer.startOneShot(0);
121 }
122
123 }
124