Cache element indices for :nth-child and :nth-last-child selectors.

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 68 matching lines @@
 #include "core/dom/Microtask.h"
 #include "core/dom/MutationObserver.h"
 #include "core/dom/NodeChildRemovalTracker.h"
 #include "core/dom/NodeFilter.h"
 #include "core/dom/NodeIterator.h"
 #include "core/dom/NodeLayoutStyle.h"
 #include "core/dom/NodeRareData.h"
 #include "core/dom/NodeRenderingTraversal.h"
 #include "core/dom/NodeTraversal.h"
 #include "core/dom/NodeWithIndex.h"
+#include "core/dom/NthIndexCache.h"
 #include "core/dom/ProcessingInstruction.h"
 #include "core/dom/RequestAnimationFrameCallback.h"
 #include "core/dom/ScriptRunner.h"
 #include "core/dom/ScriptedAnimationController.h"
 #include "core/dom/SelectorQuery.h"
 #include "core/dom/StaticNodeList.h"
 #include "core/dom/StyleEngine.h"
 #include "core/dom/TouchList.h"
 #include "core/dom/TransformSource.h"
 #include "core/dom/TreeWalker.h"
@@ skipping 368 matching lines @@
     , m_writeRecursionDepth(0)
     , m_taskRunner(MainThreadTaskRunner::create(this))
     , m_registrationContext(initializer.registrationContext(this))
     , m_elementDataCacheClearTimer(this, &Document::elementDataCacheClearTimerFired)
     , m_timeline(AnimationTimeline::create(this))
     , m_templateDocumentHost(nullptr)
     , m_didAssociateFormControlsTimer(this, &Document::didAssociateFormControlsTimerFired)
     , m_hasViewportUnits(false)
     , m_styleRecalcElementCounter(0)
     , m_parserSyncPolicy(AllowAsynchronousParsing)
+    , m_useNthIndexCache(false)
 {
     if (m_frame) {
         ASSERT(m_frame->page());
         provideContextFeaturesToDocumentFrom(*this, *m_frame->page());
 
         m_fetcher = m_frame->loader().documentLoader()->fetcher();
     }
 
     if (!m_fetcher)
         m_fetcher = FrameFetchContext::createContextAndFetcher(nullptr);
@@ skipping 162 matching lines @@
 }
 #endif
 
 SelectorQueryCache& Document::selectorQueryCache()
 {
     if (!m_selectorQueryCache)
         m_selectorQueryCache = adoptPtr(new SelectorQueryCache());
     return *m_selectorQueryCache;
 }
 
+NthIndexCache* Document::nthIndexCache()
+{
+    if (!m_useNthIndexCache)
+        return nullptr;
+    if (!m_nthIndexCache)
+        m_nthIndexCache = adoptPtr(new NthIndexCache(*this));

[sof, 2015/03/28 08:33:59]

adoptPtrWillBeNoop() -- would be tidier to provide
NthIndexCache::create(Document&)

[rune, 2015/03/30 09:00:03]

Done.

[sof, 2015/03/30 20:55:16]

Oh, not quite, you're still using adoptPtr() -- ought to be

  static PassOwnPtrWillBeRawPtr<NthIndexCache> create(Document& document)
  {
      return adoptPtrWillBeNoop(new NthIndexCache(document));
  }

+    return m_nthIndexCache.get();
+}
+
+void Document::setUseNthIndexCache(bool use)
+{
+    m_useNthIndexCache = use;
+    if (!use && m_nthIndexCache)
+        m_nthIndexCache->clear();
+}
+
 MediaQueryMatcher& Document::mediaQueryMatcher()
 {
     if (!m_mediaQueryMatcher)
         m_mediaQueryMatcher = MediaQueryMatcher::create(*this);
     return *m_mediaQueryMatcher;
 }
 
 void Document::mediaQueryAffectingValueChanged()
 {
     m_evaluateMediaQueriesOnStyleRecalc = true;
@@ skipping 1037 matching lines @@
 
     if (!view() || !isActive())
         return;
 
     if (change != Force && !needsRenderTreeUpdate())
         return;
 
     if (inStyleRecalc())
         return;
 
+    UseNthIndexCacheScope nthIndexScope(*this);
+
     // Entering here from inside layout or paint would be catastrophic since recalcStyle can
     // tear down the render tree or (unfortunately) run script. Kill the whole renderer if
     // someone managed to get into here from inside layout or paint.
     RELEASE_ASSERT(!view()->isInPerformLayout());
     RELEASE_ASSERT(!view()->isPainting());
 
     // Script can run below in WidgetUpdates, so protect the LocalFrame.
     // FIXME: Can this still happen? How does script run inside
     // UpdateSuspendScope::performDeferredWidgetTreeOperations() ?
     RefPtrWillBeRawPtr<LocalFrame> protect(m_frame.get());
@@ skipping 4005 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     WeakDocumentSet& set = liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().string().utf8().data());
 }
 #endif