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/*
* Copyright (C) 2010 Google, Inc. All Rights Reserved.
* Copyright (C) 2015-2017 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 "HTMLDocumentParser.h"
#include "CustomHeaderFields.h"
#include "CustomElementReactionQueue.h"
#include "DocumentFragment.h"
#include "DocumentLoader.h"
#include "Frame.h"
#include "HTMLDocument.h"
#include "HTMLParserScheduler.h"
#include "HTMLPreloadScanner.h"
#include "HTMLScriptRunner.h"
#include "HTMLTreeBuilder.h"
#include "HTMLUnknownElement.h"
#include "JSCustomElementInterface.h"
#include "LinkLoader.h"
#include "Microtasks.h"
#include "NavigationScheduler.h"
#include "ScriptElement.h"
#include "ThrowOnDynamicMarkupInsertionCountIncrementer.h"
namespace WebCore {
using namespace HTMLNames;
HTMLDocumentParser::HTMLDocumentParser(HTMLDocument& document)
: ScriptableDocumentParser(document)
, m_options(document)
, m_tokenizer(m_options)
, m_scriptRunner(makeUnique<HTMLScriptRunner>(document, static_cast<HTMLScriptRunnerHost&>(*this)))
, m_treeBuilder(makeUnique<HTMLTreeBuilder>(*this, document, parserContentPolicy(), m_options))
, m_parserScheduler(makeUnique<HTMLParserScheduler>(*this))
, m_xssAuditorDelegate(document)
, m_preloader(makeUnique<HTMLResourcePreloader>(document))
{
}
Ref<HTMLDocumentParser> HTMLDocumentParser::create(HTMLDocument& document)
{
return adoptRef(*new HTMLDocumentParser(document));
}
inline HTMLDocumentParser::HTMLDocumentParser(DocumentFragment& fragment, Element& contextElement, ParserContentPolicy rawPolicy)
: ScriptableDocumentParser(fragment.document(), rawPolicy)
, m_options(fragment.document())
, m_tokenizer(m_options)
, m_treeBuilder(makeUnique<HTMLTreeBuilder>(*this, fragment, contextElement, parserContentPolicy(), m_options))
, m_xssAuditorDelegate(fragment.document())
{
// https://html.spec.whatwg.org/multipage/syntax.html#parsing-html-fragments
if (contextElement.isHTMLElement())
m_tokenizer.updateStateFor(contextElement.tagQName().localName());
m_xssAuditor.initForFragment();
}
inline Ref<HTMLDocumentParser> HTMLDocumentParser::create(DocumentFragment& fragment, Element& contextElement, ParserContentPolicy parserContentPolicy)
{
return adoptRef(*new HTMLDocumentParser(fragment, contextElement, parserContentPolicy));
}
HTMLDocumentParser::~HTMLDocumentParser()
{
ASSERT(!m_parserScheduler);
ASSERT(!m_pumpSessionNestingLevel);
ASSERT(!m_preloadScanner);
ASSERT(!m_insertionPreloadScanner);
}
void HTMLDocumentParser::detach()
{
ScriptableDocumentParser::detach();
if (m_scriptRunner)
m_scriptRunner->detach();
// FIXME: It seems wrong that we would have a preload scanner here.
// Yet during fast/dom/HTMLScriptElement/script-load-events.html we do.
m_preloadScanner = nullptr;
m_insertionPreloadScanner = nullptr;
m_parserScheduler = nullptr; // Deleting the scheduler will clear any timers.
}
void HTMLDocumentParser::stopParsing()
{
DocumentParser::stopParsing();
m_parserScheduler = nullptr; // Deleting the scheduler will clear any timers.
}
// This kicks off "Once the user agent stops parsing" as described by:
// https://html.spec.whatwg.org/multipage/syntax.html#the-end
void HTMLDocumentParser::prepareToStopParsing()
{
ASSERT(!hasInsertionPoint());
// pumpTokenizer can cause this parser to be detached from the Document,
// but we need to ensure it isn't deleted yet.
Ref<HTMLDocumentParser> protectedThis(*this);
// NOTE: This pump should only ever emit buffered character tokens,
// so ForceSynchronous vs. AllowYield should be meaningless.
pumpTokenizerIfPossible(ForceSynchronous);
if (isStopped())
return;
DocumentParser::prepareToStopParsing();
// We will not have a scriptRunner when parsing a DocumentFragment.
if (m_scriptRunner)
document()->setReadyState(Document::Interactive);
// Setting the ready state above can fire mutation event and detach us
// from underneath. In that case, just bail out.
if (isDetached())
return;
attemptToRunDeferredScriptsAndEnd();
}
inline bool HTMLDocumentParser::inPumpSession() const
{
return m_pumpSessionNestingLevel > 0;
}
inline bool HTMLDocumentParser::shouldDelayEnd() const
{
return inPumpSession() || isWaitingForScripts() || isScheduledForResume() || isExecutingScript();
}
void HTMLDocumentParser::didBeginYieldingParser()
{
m_parserScheduler->didBeginYieldingParser();
}
void HTMLDocumentParser::didEndYieldingParser()
{
m_parserScheduler->didEndYieldingParser();
}
bool HTMLDocumentParser::isParsingFragment() const
{
return m_treeBuilder->isParsingFragment();
}
bool HTMLDocumentParser::processingData() const
{
return isScheduledForResume() || inPumpSession();
}
void HTMLDocumentParser::pumpTokenizerIfPossible(SynchronousMode mode)
{
if (isStopped() || isWaitingForScripts())
return;
// Once a resume is scheduled, HTMLParserScheduler controls when we next pump.
if (isScheduledForResume()) {
ASSERT(mode == AllowYield);
return;
}
pumpTokenizer(mode);
}
bool HTMLDocumentParser::isScheduledForResume() const
{
return m_parserScheduler && m_parserScheduler->isScheduledForResume();
}
// Used by HTMLParserScheduler
void HTMLDocumentParser::resumeParsingAfterYield()
{
// pumpTokenizer can cause this parser to be detached from the Document,
// but we need to ensure it isn't deleted yet.
Ref<HTMLDocumentParser> protectedThis(*this);
// We should never be here unless we can pump immediately.
// Call pumpTokenizer() directly so that ASSERTS will fire if we're wrong.
pumpTokenizer(AllowYield);
endIfDelayed();
}
void HTMLDocumentParser::runScriptsForPausedTreeBuilder()
{
ASSERT(scriptingContentIsAllowed(parserContentPolicy()));
if (std::unique_ptr<CustomElementConstructionData> constructionData = m_treeBuilder->takeCustomElementConstructionData()) {
ASSERT(!m_treeBuilder->hasParserBlockingScriptWork());
// https://html.spec.whatwg.org/#create-an-element-for-the-token
{
// Prevent document.open/write during reactions by allocating the incrementer before the reactions stack.
ThrowOnDynamicMarkupInsertionCountIncrementer incrementer(*document());
MicrotaskQueue::mainThreadQueue().performMicrotaskCheckpoint();
CustomElementReactionStack reactionStack(document()->execState());
auto& elementInterface = constructionData->elementInterface.get();
auto newElement = elementInterface.constructElementWithFallback(*document(), constructionData->name);
m_treeBuilder->didCreateCustomOrFallbackElement(WTFMove(newElement), *constructionData);
}
return;
}
TextPosition scriptStartPosition = TextPosition::belowRangePosition();
if (auto scriptElement = m_treeBuilder->takeScriptToProcess(scriptStartPosition)) {
ASSERT(!m_treeBuilder->hasParserBlockingScriptWork());
// We will not have a scriptRunner when parsing a DocumentFragment.
if (m_scriptRunner)
m_scriptRunner->execute(scriptElement.releaseNonNull(), scriptStartPosition);
}
}
Document* HTMLDocumentParser::contextForParsingSession()
{
// The parsing session should interact with the document only when parsing
// non-fragments. Otherwise, we might delay the load event mistakenly.
if (isParsingFragment())
return nullptr;
return document();
}
bool HTMLDocumentParser::pumpTokenizerLoop(SynchronousMode mode, bool parsingFragment, PumpSession& session)
{
do {
if (UNLIKELY(isWaitingForScripts())) {
if (mode == AllowYield && m_parserScheduler->shouldYieldBeforeExecutingScript(session))
return true;
runScriptsForPausedTreeBuilder();
// If we're paused waiting for a script, we try to execute scripts before continuing.
if (isWaitingForScripts() || isStopped())
return false;
}
// FIXME: It's wrong for the HTMLDocumentParser to reach back to the Frame, but this approach is
// how the parser has always handled stopping when the page assigns window.location. What should
// happen instead is that assigning window.location causes the parser to stop parsing cleanly.
// The problem is we're not prepared to do that at every point where we run JavaScript.
if (UNLIKELY(!parsingFragment && document()->frame() && document()->frame()->navigationScheduler().locationChangePending()))
return false;
if (UNLIKELY(mode == AllowYield && m_parserScheduler->shouldYieldBeforeToken(session)))
return true;
if (!parsingFragment)
m_sourceTracker.startToken(m_input.current(), m_tokenizer);
auto token = m_tokenizer.nextToken(m_input.current());
if (!token)
return false;
if (!parsingFragment) {
m_sourceTracker.endToken(m_input.current(), m_tokenizer);
// We do not XSS filter innerHTML, which means we (intentionally) fail
// http/tests/security/xssAuditor/dom-write-innerHTML.html
if (auto xssInfo = m_xssAuditor.filterToken(FilterTokenRequest(*token, m_sourceTracker, m_tokenizer.shouldAllowCDATA())))
m_xssAuditorDelegate.didBlockScript(*xssInfo);
}
constructTreeFromHTMLToken(token);
} while (!isStopped());
return false;
}
void HTMLDocumentParser::pumpTokenizer(SynchronousMode mode)
{
ASSERT(!isStopped());
ASSERT(!isScheduledForResume());
// This is an attempt to check that this object is both attached to the Document and protected by something.
ASSERT(refCount() >= 2);
PumpSession session(m_pumpSessionNestingLevel, contextForParsingSession());
m_xssAuditor.init(document(), &m_xssAuditorDelegate);
bool shouldResume = pumpTokenizerLoop(mode, isParsingFragment(), session);
// Ensure we haven't been totally deref'ed after pumping. Any caller of this
// function should be holding a RefPtr to this to ensure we weren't deleted.
ASSERT(refCount() >= 1);
if (isStopped())
return;
if (shouldResume)
m_parserScheduler->scheduleForResume();
if (isWaitingForScripts()) {
ASSERT(m_tokenizer.isInDataState());
if (!m_preloadScanner) {
m_preloadScanner = makeUnique<HTMLPreloadScanner>(m_options, document()->url(), document()->deviceScaleFactor());
m_preloadScanner->appendToEnd(m_input.current());
}
m_preloadScanner->scan(*m_preloader, *document());
}
// The viewport definition is known here, so we can load link preloads with media attributes.
if (document()->loader())
LinkLoader::loadLinksFromHeader(document()->loader()->response().httpHeaderField(HTTPHeaderName::Link), document()->url(), *document(), LinkLoader::MediaAttributeCheck::MediaAttributeNotEmpty);
}
void HTMLDocumentParser::constructTreeFromHTMLToken(HTMLTokenizer::TokenPtr& rawToken)
{
AtomicHTMLToken token(*rawToken);
// We clear the rawToken in case constructTreeFromAtomicToken
// synchronously re-enters the parser. We don't clear the token immedately
// for Character tokens because the AtomicHTMLToken avoids copying the
// characters by keeping a pointer to the underlying buffer in the
// HTMLToken. Fortunately, Character tokens can't cause us to re-enter
// the parser.
//
// FIXME: Stop clearing the rawToken once we start running the parser off
// the main thread or once we stop allowing synchronous JavaScript
// execution from parseAttribute.
if (rawToken->type() != HTMLToken::Character) {
// Clearing the TokenPtr makes sure we don't clear the HTMLToken a second time
// later when the TokenPtr is destroyed.
rawToken.clear();
}
m_treeBuilder->constructTree(WTFMove(token));
}
bool HTMLDocumentParser::hasInsertionPoint()
{
// FIXME: The wasCreatedByScript() branch here might not be fully correct.
// Our model of the EOF character differs slightly from the one in the spec
// because our treatment is uniform between network-sourced and script-sourced
// input streams whereas the spec treats them differently.
return m_input.hasInsertionPoint() || (wasCreatedByScript() && !m_input.haveSeenEndOfFile());
}
void HTMLDocumentParser::insert(SegmentedString&& source)
{
if (isStopped())
return;
// pumpTokenizer can cause this parser to be detached from the Document,
// but we need to ensure it isn't deleted yet.
Ref<HTMLDocumentParser> protectedThis(*this);
source.setExcludeLineNumbers();
m_input.insertAtCurrentInsertionPoint(WTFMove(source));
pumpTokenizerIfPossible(ForceSynchronous);
if (isWaitingForScripts()) {
// Check the document.write() output with a separate preload scanner as
// the main scanner can't deal with insertions.
if (!m_insertionPreloadScanner)
m_insertionPreloadScanner = makeUnique<HTMLPreloadScanner>(m_options, document()->url(), document()->deviceScaleFactor());
m_insertionPreloadScanner->appendToEnd(source);
m_insertionPreloadScanner->scan(*m_preloader, *document());
}
endIfDelayed();
}
void HTMLDocumentParser::append(RefPtr<StringImpl>&& inputSource)
{
if (isStopped())
return;
// pumpTokenizer can cause this parser to be detached from the Document,
// but we need to ensure it isn't deleted yet.
Ref<HTMLDocumentParser> protectedThis(*this);
String source { WTFMove(inputSource) };
if (m_preloadScanner) {
if (m_input.current().isEmpty() && !isWaitingForScripts()) {
// We have parsed until the end of the current input and so are now moving ahead of the preload scanner.
// Clear the scanner so we know to scan starting from the current input point if we block again.
m_preloadScanner = nullptr;
} else {
m_preloadScanner->appendToEnd(source);
if (isWaitingForScripts())
m_preloadScanner->scan(*m_preloader, *document());
}
}
m_input.appendToEnd(source);
if (inPumpSession()) {
// We've gotten data off the network in a nested write.
// We don't want to consume any more of the input stream now. Do
// not worry. We'll consume this data in a less-nested write().
return;
}
pumpTokenizerIfPossible(AllowYield);
endIfDelayed();
}
void HTMLDocumentParser::end()
{
ASSERT(!isDetached());
ASSERT(!isScheduledForResume());
// Informs the rest of WebCore that parsing is really finished (and deletes this).
m_treeBuilder->finished();
}
void HTMLDocumentParser::attemptToRunDeferredScriptsAndEnd()
{
ASSERT(isStopping());
ASSERT(!hasInsertionPoint());
if (m_scriptRunner && !m_scriptRunner->executeScriptsWaitingForParsing())
return;
end();
}
void HTMLDocumentParser::attemptToEnd()
{
// finish() indicates we will not receive any more data. If we are waiting on
// an external script to load, we can't finish parsing quite yet.
if (shouldDelayEnd()) {
m_endWasDelayed = true;
return;
}
prepareToStopParsing();
}
void HTMLDocumentParser::endIfDelayed()
{
// If we've already been detached, don't bother ending.
if (isDetached())
return;
if (!m_endWasDelayed || shouldDelayEnd())
return;
m_endWasDelayed = false;
prepareToStopParsing();
}
void HTMLDocumentParser::finish()
{
// FIXME: We should ASSERT(!m_parserStopped) here, since it does not
// makes sense to call any methods on DocumentParser once it's been stopped.
// However, FrameLoader::stop calls DocumentParser::finish unconditionally.
// We're not going to get any more data off the network, so we tell the
// input stream we've reached the end of file. finish() can be called more
// than once, if the first time does not call end().
if (!m_input.haveSeenEndOfFile())
m_input.markEndOfFile();
attemptToEnd();
}
bool HTMLDocumentParser::isExecutingScript() const
{
return m_scriptRunner && m_scriptRunner->isExecutingScript();
}
TextPosition HTMLDocumentParser::textPosition() const
{
auto& currentString = m_input.current();
return TextPosition(currentString.currentLine(), currentString.currentColumn());
}
bool HTMLDocumentParser::shouldAssociateConsoleMessagesWithTextPosition() const
{
return inPumpSession() && !isExecutingScript();
}
bool HTMLDocumentParser::isWaitingForScripts() const
{
// When the TreeBuilder encounters a </script> tag, it returns to the HTMLDocumentParser
// where the script is transfered from the treebuilder to the script runner.
// The script runner will hold the script until its loaded and run. During
// any of this time, we want to count ourselves as "waiting for a script" and thus
// run the preload scanner, as well as delay completion of parsing.
bool treeBuilderHasBlockingScript = m_treeBuilder->hasParserBlockingScriptWork();
bool scriptRunnerHasBlockingScript = m_scriptRunner && m_scriptRunner->hasParserBlockingScript();
// Since the parser is paused while a script runner has a blocking script, it should
// never be possible to end up with both objects holding a blocking script.
ASSERT(!(treeBuilderHasBlockingScript && scriptRunnerHasBlockingScript));
// If either object has a blocking script, the parser should be paused.
return treeBuilderHasBlockingScript || scriptRunnerHasBlockingScript;
}
void HTMLDocumentParser::resumeParsingAfterScriptExecution()
{
ASSERT(!isExecutingScript());
ASSERT(!isWaitingForScripts());
// pumpTokenizer can cause this parser to be detached from the Document,
// but we need to ensure it isn't deleted yet.
Ref<HTMLDocumentParser> protectedThis(*this);
m_insertionPreloadScanner = nullptr;
pumpTokenizerIfPossible(AllowYield);
endIfDelayed();
}
void HTMLDocumentParser::watchForLoad(PendingScript& pendingScript)
{
ASSERT(!pendingScript.isLoaded());
// setClient would call notifyFinished if the load were complete.
// Callers do not expect to be re-entered from this call, so they should
// not an already-loaded PendingScript.
pendingScript.setClient(*this);
}
void HTMLDocumentParser::stopWatchingForLoad(PendingScript& pendingScript)
{
pendingScript.clearClient();
}
void HTMLDocumentParser::appendCurrentInputStreamToPreloadScannerAndScan()
{
ASSERT(m_preloadScanner);
m_preloadScanner->appendToEnd(m_input.current());
m_preloadScanner->scan(*m_preloader, *document());
}
void HTMLDocumentParser::notifyFinished(PendingScript& pendingScript)
{
// pumpTokenizer can cause this parser to be detached from the Document,
// but we need to ensure it isn't deleted yet.
Ref<HTMLDocumentParser> protectedThis(*this);
// After Document parser is stopped or detached, the parser-inserted deferred script execution should be ignored.
if (isStopped())
return;
ASSERT(m_scriptRunner);
ASSERT(!isExecutingScript());
if (isStopping()) {
attemptToRunDeferredScriptsAndEnd();
return;
}
m_scriptRunner->executeScriptsWaitingForLoad(pendingScript);
if (!isWaitingForScripts())
resumeParsingAfterScriptExecution();
}
bool HTMLDocumentParser::hasScriptsWaitingForStylesheets() const
{
return m_scriptRunner && m_scriptRunner->hasScriptsWaitingForStylesheets();
}
void HTMLDocumentParser::executeScriptsWaitingForStylesheets()
{
// Document only calls this when the Document owns the DocumentParser
// so this will not be called in the DocumentFragment case.
ASSERT(m_scriptRunner);
// Ignore calls unless we have a script blocking the parser waiting on a
// stylesheet load. Otherwise we are currently parsing and this
// is a re-entrant call from encountering a </ style> tag.
if (!m_scriptRunner->hasScriptsWaitingForStylesheets())
return;
// pumpTokenizer can cause this parser to be detached from the Document,
// but we need to ensure it isn't deleted yet.
Ref<HTMLDocumentParser> protectedThis(*this);
m_scriptRunner->executeScriptsWaitingForStylesheets();
if (!isWaitingForScripts())
resumeParsingAfterScriptExecution();
}
void HTMLDocumentParser::parseDocumentFragment(const String& source, DocumentFragment& fragment, Element& contextElement, ParserContentPolicy parserContentPolicy)
{
auto parser = create(fragment, contextElement, parserContentPolicy);
parser->insert(source); // Use insert() so that the parser will not yield.
parser->finish();
ASSERT(!parser->processingData());
parser->detach();
}
void HTMLDocumentParser::suspendScheduledTasks()
{
if (m_parserScheduler)
m_parserScheduler->suspend();
}
void HTMLDocumentParser::resumeScheduledTasks()
{
if (m_parserScheduler)
m_parserScheduler->resume();
}
}