diff -r 000000000000 -r 6474c204b198 parser/html/nsHtml5TreeOpExecutor.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/parser/html/nsHtml5TreeOpExecutor.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,951 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=2 et tw=79: */
+/* 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 "mozilla/DebugOnly.h"
+#include "mozilla/Likely.h"
+
+#include "nsError.h"
+#include "nsHtml5TreeOpExecutor.h"
+#include "nsScriptLoader.h"
+#include "nsIMarkupDocumentViewer.h"
+#include "nsIContentViewer.h"
+#include "nsIDocShellTreeItem.h"
+#include "nsIDocShell.h"
+#include "nsIScriptGlobalObject.h"
+#include "nsIScriptSecurityManager.h"
+#include "nsIWebShellServices.h"
+#include "nsContentUtils.h"
+#include "mozAutoDocUpdate.h"
+#include "nsNetUtil.h"
+#include "nsHtml5Parser.h"
+#include "nsHtml5Tokenizer.h"
+#include "nsHtml5TreeBuilder.h"
+#include "nsHtml5StreamParser.h"
+#include "mozilla/css/Loader.h"
+#include "GeckoProfiler.h"
+#include "nsIScriptError.h"
+#include "nsIScriptContext.h"
+#include "mozilla/Preferences.h"
+#include "nsIHTMLDocument.h"
+
+using namespace mozilla;
+
+NS_INTERFACE_TABLE_HEAD_CYCLE_COLLECTION_INHERITED(nsHtml5TreeOpExecutor)
+  NS_INTERFACE_TABLE_INHERITED(nsHtml5TreeOpExecutor, 
+                               nsIContentSink)
+NS_INTERFACE_TABLE_TAIL_INHERITING(nsHtml5DocumentBuilder)
+
+NS_IMPL_ADDREF_INHERITED(nsHtml5TreeOpExecutor, nsContentSink)
+
+NS_IMPL_RELEASE_INHERITED(nsHtml5TreeOpExecutor, nsContentSink)
+
+class nsHtml5ExecutorReflusher : public nsRunnable
+{
+  private:
+    nsRefPtr<nsHtml5TreeOpExecutor> mExecutor;
+  public:
+    nsHtml5ExecutorReflusher(nsHtml5TreeOpExecutor* aExecutor)
+      : mExecutor(aExecutor)
+    {}
+    NS_IMETHODIMP Run()
+    {
+      mExecutor->RunFlushLoop();
+      return NS_OK;
+    }
+};
+
+static mozilla::LinkedList<nsHtml5TreeOpExecutor>* gBackgroundFlushList = nullptr;
+static nsITimer* gFlushTimer = nullptr;
+
+nsHtml5TreeOpExecutor::nsHtml5TreeOpExecutor()
+  : nsHtml5DocumentBuilder(false)
+  , mPreloadedURLs(23)  // Mean # of preloadable resources per page on dmoz
+{
+  // zeroing operator new for everything else
+}
+
+nsHtml5TreeOpExecutor::~nsHtml5TreeOpExecutor()
+{
+  if (gBackgroundFlushList && isInList()) {
+    mOpQueue.Clear();
+    removeFrom(*gBackgroundFlushList);
+    if (gBackgroundFlushList->isEmpty()) {
+      delete gBackgroundFlushList;
+      gBackgroundFlushList = nullptr;
+      if (gFlushTimer) {
+        gFlushTimer->Cancel();
+        NS_RELEASE(gFlushTimer);
+      }
+    }
+  }
+  NS_ASSERTION(mOpQueue.IsEmpty(), "Somehow there's stuff in the op queue.");
+}
+
+// nsIContentSink
+NS_IMETHODIMP
+nsHtml5TreeOpExecutor::WillParse()
+{
+  NS_NOTREACHED("No one should call this");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsHtml5TreeOpExecutor::WillBuildModel(nsDTDMode aDTDMode)
+{
+  mDocument->AddObserver(this);
+  WillBuildModelImpl();
+  GetDocument()->BeginLoad();
+  if (mDocShell && !GetDocument()->GetWindow() &&
+      !IsExternalViewSource()) {
+    // Not loading as data but script global object not ready
+    return MarkAsBroken(NS_ERROR_DOM_INVALID_STATE_ERR);
+  }
+  return NS_OK;
+}
+
+
+// This is called when the tree construction has ended
+NS_IMETHODIMP
+nsHtml5TreeOpExecutor::DidBuildModel(bool aTerminated)
+{
+  if (!aTerminated) {
+    // This is needed to avoid unblocking loads too many times on one hand
+    // and on the other hand to avoid destroying the frame constructor from
+    // within an update batch. See bug 537683.
+    EndDocUpdate();
+    
+    // If the above caused a call to nsIParser::Terminate(), let that call
+    // win.
+    if (!mParser) {
+      return NS_OK;
+    }
+  }
+  
+  if (mRunsToCompletion) {
+    return NS_OK;
+  }
+
+  GetParser()->DropStreamParser();
+
+  // This comes from nsXMLContentSink and nsHTMLContentSink
+  // If this parser has been marked as broken, treat the end of parse as
+  // forced termination.
+  DidBuildModelImpl(aTerminated || NS_FAILED(IsBroken()));
+
+  if (!mLayoutStarted) {
+    // We never saw the body, and layout never got started. Force
+    // layout *now*, to get an initial reflow.
+
+    // NOTE: only force the layout if we are NOT destroying the
+    // docshell. If we are destroying it, then starting layout will
+    // likely cause us to crash, or at best waste a lot of time as we
+    // are just going to tear it down anyway.
+    bool destroying = true;
+    if (mDocShell) {
+      mDocShell->IsBeingDestroyed(&destroying);
+    }
+
+    if (!destroying) {
+      nsContentSink::StartLayout(false);
+    }
+  }
+
+  ScrollToRef();
+  mDocument->RemoveObserver(this);
+  if (!mParser) {
+    // DidBuildModelImpl may cause mParser to be nulled out
+    // Return early to avoid unblocking the onload event too many times.
+    return NS_OK;
+  }
+
+  // We may not have called BeginLoad() if loading is terminated before
+  // OnStartRequest call.
+  if (mStarted) {
+    mDocument->EndLoad();
+  }
+  DropParserAndPerfHint();
+#ifdef GATHER_DOCWRITE_STATISTICS
+  printf("UNSAFE SCRIPTS: %d\n", sUnsafeDocWrites);
+  printf("TOKENIZER-SAFE SCRIPTS: %d\n", sTokenSafeDocWrites);
+  printf("TREEBUILDER-SAFE SCRIPTS: %d\n", sTreeSafeDocWrites);
+#endif
+#ifdef DEBUG_NS_HTML5_TREE_OP_EXECUTOR_FLUSH
+  printf("MAX NOTIFICATION BATCH LEN: %d\n", sAppendBatchMaxSize);
+  if (sAppendBatchExaminations != 0) {
+    printf("AVERAGE SLOTS EXAMINED: %d\n", sAppendBatchSlotsExamined / sAppendBatchExaminations);
+  }
+#endif
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsHtml5TreeOpExecutor::WillInterrupt()
+{
+  NS_NOTREACHED("Don't call. For interface compat only.");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsHtml5TreeOpExecutor::WillResume()
+{
+  NS_NOTREACHED("Don't call. For interface compat only.");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsHtml5TreeOpExecutor::SetParser(nsParserBase* aParser)
+{
+  mParser = aParser;
+  return NS_OK;
+}
+
+void
+nsHtml5TreeOpExecutor::FlushPendingNotifications(mozFlushType aType)
+{
+  if (aType >= Flush_InterruptibleLayout) {
+    // Bug 577508 / 253951
+    nsContentSink::StartLayout(true);
+  }
+}
+
+nsISupports*
+nsHtml5TreeOpExecutor::GetTarget()
+{
+  return mDocument;
+}
+
+nsresult
+nsHtml5TreeOpExecutor::MarkAsBroken(nsresult aReason)
+{
+  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
+  mBroken = aReason;
+  if (mStreamParser) {
+    mStreamParser->Terminate();
+  }
+  // We are under memory pressure, but let's hope the following allocation
+  // works out so that we get to terminate and clean up the parser from
+  // a safer point.
+  if (mParser) { // can mParser ever be null here?
+    nsCOMPtr<nsIRunnable> terminator =
+      NS_NewRunnableMethod(GetParser(), &nsHtml5Parser::Terminate);
+    if (NS_FAILED(NS_DispatchToMainThread(terminator))) {
+      NS_WARNING("failed to dispatch executor flush event");
+    }
+  }
+  return aReason;
+}
+
+void
+FlushTimerCallback(nsITimer* aTimer, void* aClosure)
+{
+  nsRefPtr<nsHtml5TreeOpExecutor> ex = gBackgroundFlushList->popFirst();
+  if (ex) {
+    ex->RunFlushLoop();
+  }
+  if (gBackgroundFlushList && gBackgroundFlushList->isEmpty()) {
+    delete gBackgroundFlushList;
+    gBackgroundFlushList = nullptr;
+    gFlushTimer->Cancel();
+    NS_RELEASE(gFlushTimer);
+  }
+}
+
+void
+nsHtml5TreeOpExecutor::ContinueInterruptedParsingAsync()
+{
+  if (!mDocument || !mDocument->IsInBackgroundWindow()) {
+    nsCOMPtr<nsIRunnable> flusher = new nsHtml5ExecutorReflusher(this);  
+    if (NS_FAILED(NS_DispatchToMainThread(flusher))) {
+      NS_WARNING("failed to dispatch executor flush event");
+    }
+  } else {
+    if (!gBackgroundFlushList) {
+      gBackgroundFlushList = new mozilla::LinkedList<nsHtml5TreeOpExecutor>();
+    }
+    if (!isInList()) {
+      gBackgroundFlushList->insertBack(this);
+    }
+    if (!gFlushTimer) {
+      nsCOMPtr<nsITimer> t = do_CreateInstance("@mozilla.org/timer;1");
+      t.swap(gFlushTimer);
+      // The timer value 50 should not hopefully slow down background pages too
+      // much, yet lets event loop to process enough between ticks.
+      // See bug 734015.
+      gFlushTimer->InitWithFuncCallback(FlushTimerCallback, nullptr,
+                                        50, nsITimer::TYPE_REPEATING_SLACK);
+    }
+  }
+}
+
+void
+nsHtml5TreeOpExecutor::FlushSpeculativeLoads()
+{
+  nsTArray<nsHtml5SpeculativeLoad> speculativeLoadQueue;
+  mStage.MoveSpeculativeLoadsTo(speculativeLoadQueue);
+  const nsHtml5SpeculativeLoad* start = speculativeLoadQueue.Elements();
+  const nsHtml5SpeculativeLoad* end = start + speculativeLoadQueue.Length();
+  for (nsHtml5SpeculativeLoad* iter = const_cast<nsHtml5SpeculativeLoad*>(start);
+       iter < end;
+       ++iter) {
+    if (MOZ_UNLIKELY(!mParser)) {
+      // An extension terminated the parser from a HTTP observer.
+      return;
+    }
+    iter->Perform(this);
+  }
+}
+
+class nsHtml5FlushLoopGuard
+{
+  private:
+    nsRefPtr<nsHtml5TreeOpExecutor> mExecutor;
+    #ifdef DEBUG_NS_HTML5_TREE_OP_EXECUTOR_FLUSH
+    uint32_t mStartTime;
+    #endif
+  public:
+    nsHtml5FlushLoopGuard(nsHtml5TreeOpExecutor* aExecutor)
+      : mExecutor(aExecutor)
+    #ifdef DEBUG_NS_HTML5_TREE_OP_EXECUTOR_FLUSH
+      , mStartTime(PR_IntervalToMilliseconds(PR_IntervalNow()))
+    #endif
+    {
+      mExecutor->mRunFlushLoopOnStack = true;
+    }
+    ~nsHtml5FlushLoopGuard()
+    {
+      #ifdef DEBUG_NS_HTML5_TREE_OP_EXECUTOR_FLUSH
+        uint32_t timeOffTheEventLoop = 
+          PR_IntervalToMilliseconds(PR_IntervalNow()) - mStartTime;
+        if (timeOffTheEventLoop > 
+            nsHtml5TreeOpExecutor::sLongestTimeOffTheEventLoop) {
+          nsHtml5TreeOpExecutor::sLongestTimeOffTheEventLoop = 
+            timeOffTheEventLoop;
+        }
+        printf("Longest time off the event loop: %d\n", 
+          nsHtml5TreeOpExecutor::sLongestTimeOffTheEventLoop);
+      #endif
+
+      mExecutor->mRunFlushLoopOnStack = false;
+    }
+};
+
+/**
+ * The purpose of the loop here is to avoid returning to the main event loop
+ */
+void
+nsHtml5TreeOpExecutor::RunFlushLoop()
+{
+  PROFILER_LABEL("html5", "RunFlushLoop");
+  if (mRunFlushLoopOnStack) {
+    // There's already a RunFlushLoop() on the call stack.
+    return;
+  }
+  
+  nsHtml5FlushLoopGuard guard(this); // this is also the self-kungfu!
+  
+  nsCOMPtr<nsISupports> parserKungFuDeathGrip(mParser);
+
+  // Remember the entry time
+  (void) nsContentSink::WillParseImpl();
+
+  for (;;) {
+    if (!mParser) {
+      // Parse has terminated.
+      mOpQueue.Clear(); // clear in order to be able to assert in destructor
+      return;
+    }
+
+    if (NS_FAILED(IsBroken())) {
+      return;
+    }
+
+    if (!mParser->IsParserEnabled()) {
+      // The parser is blocked.
+      return;
+    }
+  
+    if (mFlushState != eNotFlushing) {
+      // XXX Can this happen? In case it can, let's avoid crashing.
+      return;
+    }
+    
+    // If there are scripts executing, then the content sink is jumping the gun
+    // (probably due to a synchronous XMLHttpRequest) and will re-enable us
+    // later, see bug 460706.
+    if (IsScriptExecuting()) {
+      return;
+    }
+
+    if (mReadingFromStage) {
+      nsTArray<nsHtml5SpeculativeLoad> speculativeLoadQueue;
+      mStage.MoveOpsAndSpeculativeLoadsTo(mOpQueue, speculativeLoadQueue);
+      // Make sure speculative loads never start after the corresponding
+      // normal loads for the same URLs.
+      const nsHtml5SpeculativeLoad* start = speculativeLoadQueue.Elements();
+      const nsHtml5SpeculativeLoad* end = start + speculativeLoadQueue.Length();
+      for (nsHtml5SpeculativeLoad* iter = (nsHtml5SpeculativeLoad*)start;
+           iter < end;
+           ++iter) {
+        iter->Perform(this);
+        if (MOZ_UNLIKELY(!mParser)) {
+          // An extension terminated the parser from a HTTP observer.
+          mOpQueue.Clear(); // clear in order to be able to assert in destructor
+          return;
+        }
+      }
+    } else {
+      FlushSpeculativeLoads(); // Make sure speculative loads never start after
+                               // the corresponding normal loads for the same
+                               // URLs.
+      if (MOZ_UNLIKELY(!mParser)) {
+        // An extension terminated the parser from a HTTP observer.
+        mOpQueue.Clear(); // clear in order to be able to assert in destructor
+        return;
+      }
+      // Not sure if this grip is still needed, but previously, the code
+      // gripped before calling ParseUntilBlocked();
+      nsRefPtr<nsHtml5StreamParser> streamKungFuDeathGrip = 
+        GetParser()->GetStreamParser();
+      // Now parse content left in the document.write() buffer queue if any.
+      // This may generate tree ops on its own or dequeue a speculation.
+      nsresult rv = GetParser()->ParseUntilBlocked();
+      if (NS_FAILED(rv)) {
+        MarkAsBroken(rv);
+        return;
+      }
+    }
+
+    if (mOpQueue.IsEmpty()) {
+      // Avoid bothering the rest of the engine with a doc update if there's 
+      // nothing to do.
+      return;
+    }
+
+    mFlushState = eInFlush;
+
+    nsIContent* scriptElement = nullptr;
+    
+    BeginDocUpdate();
+
+    uint32_t numberOfOpsToFlush = mOpQueue.Length();
+
+    SetAppendBatchCapacity(numberOfOpsToFlush * 2);
+
+    const nsHtml5TreeOperation* first = mOpQueue.Elements();
+    const nsHtml5TreeOperation* last = first + numberOfOpsToFlush - 1;
+    for (nsHtml5TreeOperation* iter = const_cast<nsHtml5TreeOperation*>(first);;) {
+      if (MOZ_UNLIKELY(!mParser)) {
+        // The previous tree op caused a call to nsIParser::Terminate().
+        break;
+      }
+      NS_ASSERTION(mFlushState == eInDocUpdate, 
+        "Tried to perform tree op outside update batch.");
+      nsresult rv = iter->Perform(this, &scriptElement);
+      if (NS_FAILED(rv)) {
+        MarkAsBroken(rv);
+        break;
+      }
+
+      // Be sure not to check the deadline if the last op was just performed.
+      if (MOZ_UNLIKELY(iter == last)) {
+        break;
+      } else if (MOZ_UNLIKELY(nsContentSink::DidProcessATokenImpl() == 
+                 NS_ERROR_HTMLPARSER_INTERRUPTED)) {
+        mOpQueue.RemoveElementsAt(0, (iter - first) + 1);
+        
+        EndDocUpdate();
+
+        mFlushState = eNotFlushing;
+
+        #ifdef DEBUG_NS_HTML5_TREE_OP_EXECUTOR_FLUSH
+          printf("REFLUSH SCHEDULED (executing ops): %d\n", 
+            ++sTimesFlushLoopInterrupted);
+        #endif
+        nsHtml5TreeOpExecutor::ContinueInterruptedParsingAsync();
+        return;
+      }
+      ++iter;
+    }
+    
+    mOpQueue.Clear();
+    
+    EndDocUpdate();
+
+    mFlushState = eNotFlushing;
+
+    if (MOZ_UNLIKELY(!mParser)) {
+      // The parse ended already.
+      return;
+    }
+
+    if (scriptElement) {
+      // must be tail call when mFlushState is eNotFlushing
+      RunScript(scriptElement);
+      
+      // Always check the clock in nsContentSink right after a script
+      StopDeflecting();
+      if (nsContentSink::DidProcessATokenImpl() == 
+          NS_ERROR_HTMLPARSER_INTERRUPTED) {
+        #ifdef DEBUG_NS_HTML5_TREE_OP_EXECUTOR_FLUSH
+          printf("REFLUSH SCHEDULED (after script): %d\n", 
+            ++sTimesFlushLoopInterrupted);
+        #endif
+        nsHtml5TreeOpExecutor::ContinueInterruptedParsingAsync();
+        return;      
+      }
+    }
+  }
+}
+
+nsresult
+nsHtml5TreeOpExecutor::FlushDocumentWrite()
+{
+  nsresult rv = IsBroken();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  FlushSpeculativeLoads(); // Make sure speculative loads never start after the
+                // corresponding normal loads for the same URLs.
+
+  if (MOZ_UNLIKELY(!mParser)) {
+    // The parse has ended.
+    mOpQueue.Clear(); // clear in order to be able to assert in destructor
+    return rv;
+  }
+  
+  if (mFlushState != eNotFlushing) {
+    // XXX Can this happen? In case it can, let's avoid crashing.
+    return rv;
+  }
+
+  mFlushState = eInFlush;
+
+  // avoid crashing near EOF
+  nsRefPtr<nsHtml5TreeOpExecutor> kungFuDeathGrip(this);
+  nsRefPtr<nsParserBase> parserKungFuDeathGrip(mParser);
+
+  NS_ASSERTION(!mReadingFromStage,
+    "Got doc write flush when reading from stage");
+
+#ifdef DEBUG
+  mStage.AssertEmpty();
+#endif
+  
+  nsIContent* scriptElement = nullptr;
+  
+  BeginDocUpdate();
+
+  uint32_t numberOfOpsToFlush = mOpQueue.Length();
+
+  SetAppendBatchCapacity(numberOfOpsToFlush * 2);
+
+  const nsHtml5TreeOperation* start = mOpQueue.Elements();
+  const nsHtml5TreeOperation* end = start + numberOfOpsToFlush;
+  for (nsHtml5TreeOperation* iter = const_cast<nsHtml5TreeOperation*>(start);
+       iter < end;
+       ++iter) {
+    if (MOZ_UNLIKELY(!mParser)) {
+      // The previous tree op caused a call to nsIParser::Terminate().
+      break;
+    }
+    NS_ASSERTION(mFlushState == eInDocUpdate, 
+      "Tried to perform tree op outside update batch.");
+    rv = iter->Perform(this, &scriptElement);
+    if (NS_FAILED(rv)) {
+      MarkAsBroken(rv);
+      break;
+    }
+  }
+
+  mOpQueue.Clear();
+  
+  EndDocUpdate();
+
+  mFlushState = eNotFlushing;
+
+  if (MOZ_UNLIKELY(!mParser)) {
+    // Ending the doc update caused a call to nsIParser::Terminate().
+    return rv;
+  }
+
+  if (scriptElement) {
+    // must be tail call when mFlushState is eNotFlushing
+    RunScript(scriptElement);
+  }
+  return rv;
+}
+
+// copied from HTML content sink
+bool
+nsHtml5TreeOpExecutor::IsScriptEnabled()
+{
+  if (!mDocument || !mDocShell)
+    return true;
+  nsCOMPtr<nsIScriptGlobalObject> globalObject = do_QueryInterface(mDocument->GetInnerWindow());
+  // Getting context is tricky if the document hasn't had its
+  // GlobalObject set yet
+  if (!globalObject) {
+    globalObject = mDocShell->GetScriptGlobalObject();
+    NS_ENSURE_TRUE(globalObject, true);
+  }
+  NS_ENSURE_TRUE(globalObject && globalObject->GetGlobalJSObject(), true);
+  return nsContentUtils::GetSecurityManager()->
+           ScriptAllowed(globalObject->GetGlobalJSObject());
+}
+
+void
+nsHtml5TreeOpExecutor::StartLayout() {
+  if (mLayoutStarted || !mDocument) {
+    return;
+  }
+
+  EndDocUpdate();
+
+  if (MOZ_UNLIKELY(!mParser)) {
+    // got terminate
+    return;
+  }
+
+  nsContentSink::StartLayout(false);
+
+  BeginDocUpdate();
+}
+
+/**
+ * The reason why this code is here and not in the tree builder even in the 
+ * main-thread case is to allow the control to return from the tokenizer 
+ * before scripts run. This way, the tokenizer is not invoked re-entrantly 
+ * although the parser is.
+ *
+ * The reason why this is called as a tail call when mFlushState is set to
+ * eNotFlushing is to allow re-entry to Flush() but only after the current 
+ * Flush() has cleared the op queue and is otherwise done cleaning up after 
+ * itself.
+ */
+void
+nsHtml5TreeOpExecutor::RunScript(nsIContent* aScriptElement)
+{
+  if (mRunsToCompletion) {
+    // We are in createContextualFragment() or in the upcoming document.parse().
+    // Do nothing. Let's not even mark scripts malformed here, because that
+    // could cause serialization weirdness later.
+    return;
+  }
+
+  NS_ASSERTION(aScriptElement, "No script to run");
+  nsCOMPtr<nsIScriptElement> sele = do_QueryInterface(aScriptElement);
+  
+  if (!mParser) {
+    NS_ASSERTION(sele->IsMalformed(), "Script wasn't marked as malformed.");
+    // We got here not because of an end tag but because the tree builder
+    // popped an incomplete script element on EOF. Returning here to avoid
+    // calling back into mParser anymore.
+    return;
+  }
+  
+  if (sele->GetScriptDeferred() || sele->GetScriptAsync()) {
+    DebugOnly<bool> block = sele->AttemptToExecute();
+    NS_ASSERTION(!block, "Defer or async script tried to block.");
+    return;
+  }
+  
+  NS_ASSERTION(mFlushState == eNotFlushing, "Tried to run script when flushing.");
+
+  mReadingFromStage = false;
+  
+  sele->SetCreatorParser(GetParser());
+
+  // Copied from nsXMLContentSink
+  // Now tell the script that it's ready to go. This may execute the script
+  // or return true, or neither if the script doesn't need executing.
+  bool block = sele->AttemptToExecute();
+
+  // If the act of insertion evaluated the script, we're fine.
+  // Else, block the parser till the script has loaded.
+  if (block) {
+    if (mParser) {
+      GetParser()->BlockParser();
+    }
+  } else {
+    // mParser may have been nulled out by now, but the flusher deals
+
+    // If this event isn't needed, it doesn't do anything. It is sometimes
+    // necessary for the parse to continue after complex situations.
+    nsHtml5TreeOpExecutor::ContinueInterruptedParsingAsync();
+  }
+}
+
+void
+nsHtml5TreeOpExecutor::Start()
+{
+  NS_PRECONDITION(!mStarted, "Tried to start when already started.");
+  mStarted = true;
+}
+
+void
+nsHtml5TreeOpExecutor::NeedsCharsetSwitchTo(const char* aEncoding,
+                                            int32_t aSource,
+                                            uint32_t aLineNumber)
+{
+  EndDocUpdate();
+
+  if (MOZ_UNLIKELY(!mParser)) {
+    // got terminate
+    return;
+  }
+  
+  nsCOMPtr<nsIWebShellServices> wss = do_QueryInterface(mDocShell);
+  if (!wss) {
+    return;
+  }
+
+  // ask the webshellservice to load the URL
+  if (NS_SUCCEEDED(wss->StopDocumentLoad())) {
+    wss->ReloadDocument(aEncoding, aSource);
+  }
+  // if the charset switch was accepted, wss has called Terminate() on the
+  // parser by now
+
+  if (!mParser) {
+    // success
+    if (aSource == kCharsetFromMetaTag) {
+      MaybeComplainAboutCharset("EncLateMetaReload", false, aLineNumber);
+    }
+    return;
+  }
+
+  if (aSource == kCharsetFromMetaTag) {
+    MaybeComplainAboutCharset("EncLateMetaTooLate", true, aLineNumber);
+  }
+
+  GetParser()->ContinueAfterFailedCharsetSwitch();
+
+  BeginDocUpdate();
+}
+
+void
+nsHtml5TreeOpExecutor::MaybeComplainAboutCharset(const char* aMsgId,
+                                                 bool aError,
+                                                 uint32_t aLineNumber)
+{
+  if (mAlreadyComplainedAboutCharset) {
+    return;
+  }
+  // The EncNoDeclaration case for advertising iframes is so common that it
+  // would result is way too many errors. The iframe case doesn't matter
+  // when the ad is an image or a Flash animation anyway. When the ad is
+  // textual, a misrendered ad probably isn't a huge loss for users.
+  // Let's suppress the message in this case.
+  // This means that errors about other different-origin iframes in mashups
+  // are lost as well, but generally, the site author isn't in control of
+  // the embedded different-origin pages anyway and can't fix problems even
+  // if alerted about them.
+  if (!strcmp(aMsgId, "EncNoDeclaration") && mDocShell) {
+    nsCOMPtr<nsIDocShellTreeItem> parent;
+    mDocShell->GetSameTypeParent(getter_AddRefs(parent));
+    if (parent) {
+      return;
+    }
+  }
+  mAlreadyComplainedAboutCharset = true;
+  nsContentUtils::ReportToConsole(aError ? nsIScriptError::errorFlag
+                                         : nsIScriptError::warningFlag,
+                                  NS_LITERAL_CSTRING("HTML parser"),
+                                  mDocument,
+                                  nsContentUtils::eHTMLPARSER_PROPERTIES,
+                                  aMsgId,
+                                  nullptr,
+                                  0,
+                                  nullptr,
+                                  EmptyString(),
+                                  aLineNumber);
+}
+
+void
+nsHtml5TreeOpExecutor::ComplainAboutBogusProtocolCharset(nsIDocument* aDoc)
+{
+  NS_ASSERTION(!mAlreadyComplainedAboutCharset,
+               "How come we already managed to complain?");
+  mAlreadyComplainedAboutCharset = true;
+  nsContentUtils::ReportToConsole(nsIScriptError::errorFlag,
+                                  NS_LITERAL_CSTRING("HTML parser"),
+                                  aDoc,
+                                  nsContentUtils::eHTMLPARSER_PROPERTIES,
+                                  "EncProtocolUnsupported");
+}
+
+nsHtml5Parser*
+nsHtml5TreeOpExecutor::GetParser()
+{
+  MOZ_ASSERT(!mRunsToCompletion);
+  return static_cast<nsHtml5Parser*>(mParser.get());
+}
+
+void
+nsHtml5TreeOpExecutor::MoveOpsFrom(nsTArray<nsHtml5TreeOperation>& aOpQueue)
+{
+  NS_PRECONDITION(mFlushState == eNotFlushing, "mOpQueue modified during tree op execution.");
+  if (mOpQueue.IsEmpty()) {
+    mOpQueue.SwapElements(aOpQueue);
+    return;
+  }
+  mOpQueue.MoveElementsFrom(aOpQueue);
+}
+
+void
+nsHtml5TreeOpExecutor::InitializeDocWriteParserState(nsAHtml5TreeBuilderState* aState, int32_t aLine)
+{
+  GetParser()->InitializeDocWriteParserState(aState, aLine);
+}
+
+nsIURI*
+nsHtml5TreeOpExecutor::GetViewSourceBaseURI()
+{
+  if (!mViewSourceBaseURI) {
+
+    // We query the channel for the baseURI because in certain situations it
+    // cannot otherwise be determined. If this process fails, fall back to the
+    // standard method.
+    nsCOMPtr<nsIViewSourceChannel> vsc;
+    vsc = do_QueryInterface(mDocument->GetChannel());
+    if (vsc) {
+      nsresult rv =  vsc->GetBaseURI(getter_AddRefs(mViewSourceBaseURI));
+      if (NS_SUCCEEDED(rv) && mViewSourceBaseURI) {
+        return mViewSourceBaseURI;
+      }
+    }
+
+    nsCOMPtr<nsIURI> orig = mDocument->GetOriginalURI();
+    bool isViewSource;
+    orig->SchemeIs("view-source", &isViewSource);
+    if (isViewSource) {
+      nsCOMPtr<nsINestedURI> nested = do_QueryInterface(orig);
+      NS_ASSERTION(nested, "URI with scheme view-source didn't QI to nested!");
+      nested->GetInnerURI(getter_AddRefs(mViewSourceBaseURI));
+    } else {
+      // Fail gracefully if the base URL isn't a view-source: URL.
+      // Not sure if this can ever happen.
+      mViewSourceBaseURI = orig;
+    }
+  }
+  return mViewSourceBaseURI;
+}
+
+//static
+void
+nsHtml5TreeOpExecutor::InitializeStatics()
+{
+  mozilla::Preferences::AddBoolVarCache(&sExternalViewSource,
+                                        "view_source.editor.external");
+}
+
+bool
+nsHtml5TreeOpExecutor::IsExternalViewSource()
+{
+  if (!sExternalViewSource) {
+    return false;
+  }
+  bool isViewSource = false;
+  if (mDocumentURI) {
+    mDocumentURI->SchemeIs("view-source", &isViewSource);
+  }
+  return isViewSource;
+}
+
+// Speculative loading
+
+already_AddRefed<nsIURI>
+nsHtml5TreeOpExecutor::ConvertIfNotPreloadedYet(const nsAString& aURL)
+{
+  if (aURL.IsEmpty()) {
+    return nullptr;
+  }
+  // The URL of the document without <base>
+  nsIURI* documentURI = mDocument->GetDocumentURI();
+  // The URL of the document with non-speculative <base>
+  nsIURI* documentBaseURI = mDocument->GetDocBaseURI();
+
+  // If the two above are different, use documentBaseURI. If they are the
+  // same, the document object isn't aware of a <base>, so attempt to use the
+  // mSpeculationBaseURI or, failing, that, documentURI.
+  nsIURI* base = (documentURI == documentBaseURI) ?
+                  (mSpeculationBaseURI ?
+                   mSpeculationBaseURI.get() : documentURI)
+                 : documentBaseURI;
+  const nsCString& charset = mDocument->GetDocumentCharacterSet();
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = NS_NewURI(getter_AddRefs(uri), aURL, charset.get(), base);
+  if (NS_FAILED(rv)) {
+    NS_WARNING("Failed to create a URI");
+    return nullptr;
+  }
+  nsAutoCString spec;
+  uri->GetSpec(spec);
+  if (mPreloadedURLs.Contains(spec)) {
+    return nullptr;
+  }
+  mPreloadedURLs.PutEntry(spec);
+  return uri.forget();
+}
+
+void
+nsHtml5TreeOpExecutor::PreloadScript(const nsAString& aURL,
+                                     const nsAString& aCharset,
+                                     const nsAString& aType,
+                                     const nsAString& aCrossOrigin,
+                                     bool aScriptFromHead)
+{
+  nsCOMPtr<nsIURI> uri = ConvertIfNotPreloadedYet(aURL);
+  if (!uri) {
+    return;
+  }
+  mDocument->ScriptLoader()->PreloadURI(uri, aCharset, aType, aCrossOrigin,
+                                        aScriptFromHead);
+}
+
+void
+nsHtml5TreeOpExecutor::PreloadStyle(const nsAString& aURL,
+                                    const nsAString& aCharset,
+                                    const nsAString& aCrossOrigin)
+{
+  nsCOMPtr<nsIURI> uri = ConvertIfNotPreloadedYet(aURL);
+  if (!uri) {
+    return;
+  }
+  mDocument->PreloadStyle(uri, aCharset, aCrossOrigin);
+}
+
+void
+nsHtml5TreeOpExecutor::PreloadImage(const nsAString& aURL,
+                                    const nsAString& aCrossOrigin)
+{
+  nsCOMPtr<nsIURI> uri = ConvertIfNotPreloadedYet(aURL);
+  if (!uri) {
+    return;
+  }
+  mDocument->MaybePreLoadImage(uri, aCrossOrigin);
+}
+
+void
+nsHtml5TreeOpExecutor::SetSpeculationBase(const nsAString& aURL)
+{
+  if (mSpeculationBaseURI) {
+    // the first one wins
+    return;
+  }
+  const nsCString& charset = mDocument->GetDocumentCharacterSet();
+  DebugOnly<nsresult> rv = NS_NewURI(getter_AddRefs(mSpeculationBaseURI), aURL,
+                                     charset.get(), mDocument->GetDocumentURI());
+  NS_WARN_IF_FALSE(NS_SUCCEEDED(rv), "Failed to create a URI");
+}
+
+#ifdef DEBUG_NS_HTML5_TREE_OP_EXECUTOR_FLUSH
+uint32_t nsHtml5TreeOpExecutor::sAppendBatchMaxSize = 0;
+uint32_t nsHtml5TreeOpExecutor::sAppendBatchSlotsExamined = 0;
+uint32_t nsHtml5TreeOpExecutor::sAppendBatchExaminations = 0;
+uint32_t nsHtml5TreeOpExecutor::sLongestTimeOffTheEventLoop = 0;
+uint32_t nsHtml5TreeOpExecutor::sTimesFlushLoopInterrupted = 0;
+#endif
+bool nsHtml5TreeOpExecutor::sExternalViewSource = false;