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/*
* 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
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "NestingLevelIncrementer.h"
#include "Timer.h"
#include <wtf/CheckedPtr.h>
#include <wtf/RefCounted.h>
#include <wtf/RefPtr.h>
#include <wtf/TZoneMalloc.h>
#if PLATFORM(IOS_FAMILY)
#include "WebCoreThread.h"
#endif
namespace WebCore {
class Document;
class HTMLDocumentParser;
class ScriptElement;
class ActiveParserSession {
public:
explicit ActiveParserSession(Document*);
~ActiveParserSession();
private:
RefPtr<Document> m_document;
};
class PumpSession : public NestingLevelIncrementer, public ActiveParserSession {
public:
PumpSession(unsigned& nestingLevel, Document*);
~PumpSession();
unsigned processedTokens { 0 };
unsigned processedTokensOnLastCheck { 0 };
unsigned processedTokensOnLastYieldBeforeScript { 0 };
MonotonicTime startTime { MonotonicTime::now() };
bool didSeeScript { false };
};
class HTMLParserScheduler final : public RefCounted<HTMLParserScheduler> {
WTF_MAKE_TZONE_ALLOCATED(HTMLParserScheduler);
WTF_MAKE_NONCOPYABLE(HTMLParserScheduler);
public:
static Ref<HTMLParserScheduler> create(HTMLDocumentParser&);
~HTMLParserScheduler();
void detach();
bool shouldYieldBeforeToken(PumpSession& session)
{
#if PLATFORM(IOS_FAMILY)
if (WebThreadShouldYield())
return true;
#endif
if (UNLIKELY(m_documentHasActiveParserYieldTokens))
return true;
if (UNLIKELY(session.processedTokens > session.processedTokensOnLastCheck + numberOfTokensBeforeCheckingForYield || session.didSeeScript))
return checkForYield(session);
++session.processedTokens;
return false;
}
bool shouldYieldBeforeExecutingScript(const ScriptElement*, PumpSession&);
void scheduleForResume();
bool isScheduledForResume() const { return m_isSuspendedWithActiveTimer || m_continueNextChunkTimer.isActive() || m_documentHasActiveParserYieldTokens; }
void suspend();
void resume();
void didBeginYieldingParser()
{
ASSERT(!m_documentHasActiveParserYieldTokens);
m_documentHasActiveParserYieldTokens = true;
}
void didEndYieldingParser()
{
ASSERT(m_documentHasActiveParserYieldTokens);
m_documentHasActiveParserYieldTokens = false;
if (!isScheduledForResume())
scheduleForResume();
}
private:
explicit HTMLParserScheduler(HTMLDocumentParser&);
static const unsigned numberOfTokensBeforeCheckingForYield = 4096; // Performance optimization
void continueNextChunkTimerFired();
bool checkForYield(PumpSession& session)
{
session.processedTokensOnLastCheck = session.processedTokens;
session.didSeeScript = false;
Seconds elapsedTime = MonotonicTime::now() - session.startTime;
return elapsedTime > m_parserTimeLimit;
}
CheckedPtr<HTMLDocumentParser> m_parser;
Seconds m_parserTimeLimit;
Timer m_continueNextChunkTimer;
bool m_isSuspendedWithActiveTimer;
#if ASSERT_ENABLED
bool m_suspended;
#endif
bool m_documentHasActiveParserYieldTokens { false };
};
} // namespace WebCore
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