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      1 /*
      2  * Copyright (C) 2013 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef CSSSelectorWatch_h
     32 #define CSSSelectorWatch_h
     33 
     34 #include "core/css/StyleRule.h"
     35 #include "core/dom/DocumentSupplementable.h"
     36 #include "platform/Timer.h"
     37 #include "wtf/HashCountedSet.h"
     38 #include "wtf/HashSet.h"
     39 #include "wtf/RefPtr.h"
     40 #include "wtf/Vector.h"
     41 #include "wtf/WeakPtr.h"
     42 #include "wtf/text/WTFString.h"
     43 
     44 namespace WebCore {
     45 
     46 class CSSSelectorWatch : public DocumentSupplement {
     47 public:
     48     virtual ~CSSSelectorWatch() { }
     49 
     50     static CSSSelectorWatch& from(Document&);
     51 
     52     void watchCSSSelectors(const Vector<String>& selectors);
     53     const Vector<RefPtr<StyleRule> >& watchedCallbackSelectors() const { return m_watchedCallbackSelectors; }
     54 
     55     void updateSelectorMatches(const Vector<String>& removedSelectors, const Vector<String>& addedSelectors);
     56 
     57 private:
     58     CSSSelectorWatch(Document&);
     59     void callbackSelectorChangeTimerFired(Timer<CSSSelectorWatch>*);
     60 
     61     Document& m_document;
     62 
     63     Vector<RefPtr<StyleRule> > m_watchedCallbackSelectors;
     64 
     65     // Maps a CSS selector string with a -webkit-callback property to the number
     66     // of matching RenderStyle objects in this document.
     67     HashCountedSet<String> m_matchingCallbackSelectors;
     68     // Selectors are relative to m_matchingCallbackSelectors's contents at
     69     // the previous call to selectorMatchChanged.
     70     HashSet<String> m_addedSelectors;
     71     HashSet<String> m_removedSelectors;
     72 
     73     Timer<CSSSelectorWatch> m_callbackSelectorChangeTimer;
     74 
     75     // When an element is reparented, the new location's style is evaluated after the expriation of the relayout timer.
     76     // We don't want to send redundant callbacks to the embedder, so this counter lets us wait another time around the event loop.
     77     int m_timerExpirations;
     78 };
     79 
     80 } // namespace WebCore
     81 
     82 #endif // CSSSelectorWatch_h
     83