text: /*
   * Copyright (C) 2013 Google 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:
   *
   *     * Redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer.
   *     * 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.
   *     * Neither the name of Google Inc. nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "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 THE COPYRIGHT
   * OWNER 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.
   */
  
  #ifndef CSSSelectorWatch_h
  #define CSSSelectorWatch_h
  
  #include "core/css/StyleRule.h"
  #include "core/dom/DocumentSupplementable.h"
  #include "platform/Timer.h"
  #include "wtf/HashCountedSet.h"
  #include "wtf/HashSet.h"
  #include "wtf/RefPtr.h"
  #include "wtf/Vector.h"
  #include "wtf/WeakPtr.h"
  #include "wtf/text/WTFString.h"
  
  namespace WebCore {
  
  class CSSSelectorWatch FINAL : public NoBaseWillBeGarbageCollectedFinalized<CSSSelectorWatch>, public DocumentSupplement {
      WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(CSSSelectorWatch);
  public:
      virtual ~CSSSelectorWatch() { }
  
      static CSSSelectorWatch& from(Document&);
  
      void watchCSSSelectors(const Vector<String>& selectors);
      const WillBeHeapVector<RefPtrWillBeMember<StyleRule> >& watchedCallbackSelectors() const { return m_watchedCallbackSelectors; }
  
      void updateSelectorMatches(const Vector<String>& removedSelectors, const Vector<String>& addedSelectors);
  
      virtual void trace(Visitor*) OVERRIDE;
  
  private:
      explicit CSSSelectorWatch(Document&);
      void callbackSelectorChangeTimerFired(Timer<CSSSelectorWatch>*);
  
      Document& m_document;
  
      WillBeHeapVector<RefPtrWillBeMember<StyleRule> > m_watchedCallbackSelectors;
  
      // Maps a CSS selector string with a -webkit-callback property to the number
      // of matching RenderStyle objects in this document.
      HashCountedSet<String> m_matchingCallbackSelectors;
      // Selectors are relative to m_matchingCallbackSelectors's contents at
      // the previous call to selectorMatchChanged.
      HashSet<String> m_addedSelectors;
      HashSet<String> m_removedSelectors;
  
      Timer<CSSSelectorWatch> m_callbackSelectorChangeTimer;
  
      // When an element is reparented, the new location's style is evaluated after the expriation of the relayout timer.
      // We don't want to send redundant callbacks to the embedder, so this counter lets us wait another time around the event loop.
      int m_timerExpirations;
  };
  
  } // namespace WebCore
  
  #endif // CSSSelectorWatch_h
  