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/*
* Copyright (C) 2010 Google, Inc. All Rights Reserved.
* Copyright (C) 2013 Apple, 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.
*/
#include "config.h"
#include "HTMLParserScheduler.h"
#include "Document.h"
#include "ElementInlines.h"
#include "HTMLDocumentParser.h"
#include "LocalFrame.h"
#include "LocalFrameView.h"
#include "Page.h"
#include "ScriptController.h"
#include "ScriptElement.h"
#include <wtf/TZoneMallocInlines.h>
namespace WebCore {
WTF_MAKE_TZONE_ALLOCATED_IMPL(HTMLParserScheduler);
static Seconds parserTimeLimit(Page* page)
{
// Always yield after exceeding this.
constexpr auto defaultParserTimeLimit = 500_ms;
// We're using the poorly named customHTMLTokenizerTimeDelay setting.
if (page && page->hasCustomHTMLTokenizerTimeDelay())
return Seconds(page->customHTMLTokenizerTimeDelay());
return defaultParserTimeLimit;
}
ActiveParserSession::ActiveParserSession(Document* document)
: m_document(document)
{
if (!m_document)
return;
m_document->incrementActiveParserCount();
}
ActiveParserSession::~ActiveParserSession()
{
if (!m_document)
return;
m_document->decrementActiveParserCount();
}
PumpSession::PumpSession(unsigned& nestingLevel, Document* document)
: NestingLevelIncrementer(nestingLevel)
, ActiveParserSession(document)
{
}
PumpSession::~PumpSession() = default;
Ref<HTMLParserScheduler> HTMLParserScheduler::create(HTMLDocumentParser& parser)
{
return adoptRef(*new HTMLParserScheduler(parser));
}
HTMLParserScheduler::HTMLParserScheduler(HTMLDocumentParser& parser)
: m_parser(&parser)
, m_parserTimeLimit(parserTimeLimit(parser.document()->page()))
, m_continueNextChunkTimer(*this, &HTMLParserScheduler::continueNextChunkTimerFired)
, m_isSuspendedWithActiveTimer(false)
#if ASSERT_ENABLED
, m_suspended(false)
#endif
{
}
HTMLParserScheduler::~HTMLParserScheduler() = default;
void HTMLParserScheduler::detach()
{
m_continueNextChunkTimer.stop();
m_parser = nullptr;
}
void HTMLParserScheduler::continueNextChunkTimerFired()
{
ASSERT(!m_suspended);
ASSERT(m_parser);
// FIXME: The timer class should handle timer priorities instead of this code.
// If a layout is scheduled, wait again to let the layout timer run first.
if (m_parser->document()->isLayoutPending()) {
m_continueNextChunkTimer.startOneShot(0_s);
return;
}
m_parser->resumeParsingAfterYield();
}
static bool parsingProgressedSinceLastYield(PumpSession& session)
{
// Only yield if there has been progress since last yield.
if (session.processedTokens > session.processedTokensOnLastYieldBeforeScript) {
session.processedTokensOnLastYieldBeforeScript = session.processedTokens;
return true;
}
return false;
}
bool HTMLParserScheduler::shouldYieldBeforeExecutingScript(const ScriptElement* scriptElement, PumpSession& session)
{
// If we've never painted before and a layout is pending, yield prior to running
// scripts to give the page a chance to paint earlier.
RefPtr<Document> document = m_parser->document();
session.didSeeScript = true;
if (!document->body())
return false;
if (!document->frame() || !document->frame()->script().canExecuteScripts(ReasonForCallingCanExecuteScripts::NotAboutToExecuteScript))
return false;
if (!document->haveStylesheetsLoaded())
return false;
if (UNLIKELY(m_documentHasActiveParserYieldTokens))
return true;
// Yield if we have never painted and there is meaningful content
if (document->view() && !document->view()->hasEverPainted() && document->view()->isVisuallyNonEmpty())
return parsingProgressedSinceLastYield(session);
auto elapsedTime = MonotonicTime::now() - session.startTime;
constexpr auto elapsedTimeLimit = 16_ms;
// Require at least some new parsed content before yielding.
constexpr auto tokenLimit = 256;
// Don't yield on very short inline scripts. This is an imperfect way to try to guess the execution cost.
constexpr auto inlineScriptLengthLimit = 1024;
if (elapsedTime < elapsedTimeLimit)
return false;
if (session.processedTokens < tokenLimit)
return false;
if (scriptElement) {
// Async and deferred scripts are not executed by the parser.
if (scriptElement->hasAsyncAttribute() || scriptElement->hasDeferAttribute())
return false;
if (!scriptElement->hasSourceAttribute() && scriptElement->scriptContent().length() < inlineScriptLengthLimit)
return false;
}
return true;
}
void HTMLParserScheduler::scheduleForResume()
{
ASSERT(!m_suspended);
m_continueNextChunkTimer.startOneShot(0_s);
}
void HTMLParserScheduler::suspend()
{
ASSERT(!m_suspended);
ASSERT(!m_isSuspendedWithActiveTimer);
#if ASSERT_ENABLED
m_suspended = true;
#endif
if (!m_continueNextChunkTimer.isActive())
return;
m_isSuspendedWithActiveTimer = true;
m_continueNextChunkTimer.stop();
}
void HTMLParserScheduler::resume()
{
ASSERT(m_suspended);
ASSERT(!m_continueNextChunkTimer.isActive());
#if ASSERT_ENABLED
m_suspended = false;
#endif
if (!m_isSuspendedWithActiveTimer)
return;
m_isSuspendedWithActiveTimer = false;
m_continueNextChunkTimer.startOneShot(0_s);
}
}
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