Quelle  nsHtml5StringParser.cpp

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsHtml5StringParser.h"
#include "nsHtml5DependentUTF16Buffer.h"
#include "nsHtml5Tokenizer.h"
#include "nsHtml5TreeBuilder.h"
#include "nsHtml5TreeOpExecutor.h"
#include "nsIContent.h"
#include "mozilla/dom/Document.h"
#include "mozilla/dom/DocumentFragment.h"

using mozilla::dom::Document;

NS_IMPL_ISUPPORTS0(nsHtml5StringParser)

nsHtml5StringParser::nsHtml5StringParser()
    : mBuilder(new nsHtml5OplessBuilder()),
      mTreeBuilder(new nsHtml5TreeBuilder(mBuilder)),
      mTokenizer(new nsHtml5Tokenizer(mTreeBuilder.get(), false)) {
  mTokenizer->setInterner(&mAtomTable);
  mTokenizer->setKeepBuffer(true);
  mTreeBuilder->setKeepBuffer(true);
}

nsHtml5StringParser::~nsHtml5StringParser() { ClearCaches(); }

nsresult nsHtml5StringParser::ParseFragment(
    const nsAString& aSourceBuffer, nsIContent* aTargetNode,
    nsAtom* aContextLocalName, int32_t aContextNamespace, bool aQuirks,
    bool aPreventScriptExecution, bool aAllowDeclarativeShadowRoots) {
  NS_ENSURE_TRUE(aSourceBuffer.Length() <= INT32_MAX, NS_ERROR_OUT_OF_MEMORY);

  Document* doc = aTargetNode->OwnerDoc();
  nsIURI* uri = doc->GetDocumentURI();
  NS_ENSURE_TRUE(uri, NS_ERROR_NOT_AVAILABLE);

  mTreeBuilder->setFragmentContext(aContextLocalName, aContextNamespace,
                                   aTargetNode, aQuirks);

#ifdef DEBUG
  if (!aPreventScriptExecution) {
    NS_ASSERTION(!aTargetNode->IsInUncomposedDoc(),
                 "If script execution isn't prevented, "
                 "the target node must not be in doc.");
    NS_ASSERTION(
        aTargetNode->NodeType() == nsINode::DOCUMENT_FRAGMENT_NODE,
        "If script execution isn't prevented, must parse to DOM fragment.");
  }
#endif

  mTreeBuilder->SetPreventScriptExecution(aPreventScriptExecution);

  return Tokenize(aSourceBuffer, doc, true, aAllowDeclarativeShadowRoots);
}

nsresult nsHtml5StringParser::ParseDocument(
    const nsAString& aSourceBuffer, Document* aTargetDoc,
    bool aScriptingEnabledForNoscriptParsing) {
  MOZ_ASSERT(!aTargetDoc->GetFirstChild());

  NS_ENSURE_TRUE(aSourceBuffer.Length() <= INT32_MAX, NS_ERROR_OUT_OF_MEMORY);

  mTreeBuilder->setFragmentContext(nullptr, kNameSpaceID_None, nullptr, false);

  mTreeBuilder->SetPreventScriptExecution(true);

  return Tokenize(aSourceBuffer, aTargetDoc,
                  aScriptingEnabledForNoscriptParsing,
                  aTargetDoc->AllowsDeclarativeShadowRoots());
}

void nsHtml5StringParser::ClearCaches() {
  mTokenizer->dropBufferIfLongerThan(0);
  mTreeBuilder->dropBufferIfLongerThan(0);
  if (mCacheClearer) {
    mCacheClearer->Disconnect();
    mCacheClearer = nullptr;
  }
}

void nsHtml5StringParser::TryCache() {
  const int32_t kMaxBuffer = 1024 * 1024;
  bool didDrop = mTokenizer->dropBufferIfLongerThan(kMaxBuffer);
  didDrop |= mTreeBuilder->dropBufferIfLongerThan(kMaxBuffer);
  if (didDrop) {
    return;
  }

  if (!mCacheClearer) {
    mCacheClearer = new CacheClearer(this);
    nsCOMPtr<nsIRunnable> runnable = mCacheClearer.get();
    NS_DispatchToMainThreadQueue(runnable.forget(),
                                 mozilla::EventQueuePriority::Idle);
  }
}

nsresult nsHtml5StringParser::Tokenize(const nsAString& aSourceBuffer,
                                       Document* aDocument,
                                       bool aScriptingEnabledForNoscriptParsing,
                                       bool aDeclarativeShadowRootsAllowed) {
  nsIURI* uri = aDocument->GetDocumentURI();

  mBuilder->Init(aDocument, uri, nullptr, nullptr);

  mBuilder->SetParser(this);
  mBuilder->SetNodeInfoManager(aDocument->NodeInfoManager());

  // Mark the parser as *not* broken by passing NS_OK
  nsresult rv = mBuilder->MarkAsBroken(NS_OK);

  mTreeBuilder->setScriptingEnabled(aScriptingEnabledForNoscriptParsing);
  mTreeBuilder->setIsSrcdocDocument(aDocument->IsSrcdocDocument());
  mTreeBuilder->setAllowDeclarativeShadowRoots(aDeclarativeShadowRootsAllowed);
  mBuilder->Start();
  mTokenizer->start();
  if (!aSourceBuffer.IsEmpty()) {
    bool lastWasCR = false;
    nsHtml5DependentUTF16Buffer buffer(aSourceBuffer);
    while (buffer.hasMore()) {
      buffer.adjust(lastWasCR);
      lastWasCR = false;
      if (buffer.hasMore()) {
        if (!mTokenizer->EnsureBufferSpace(buffer.getLength())) {
          rv = mBuilder->MarkAsBroken(NS_ERROR_OUT_OF_MEMORY);
          break;
        }
        lastWasCR = mTokenizer->tokenizeBuffer(&buffer);
        if (NS_FAILED(rv = mBuilder->IsBroken())) {
          break;
        }
      }
    }
  }
  if (NS_SUCCEEDED(rv)) {
    mTokenizer->eof();
  }

  mTokenizer->end();
  mBuilder->Finish();
  mAtomTable.Clear();
  TryCache();
  return rv;
}