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      1 /*
      2  * Copyright (C) 2009 Apple 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
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef CanvasRenderingContext_h
     27 #define CanvasRenderingContext_h
     28 
     29 #include "bindings/v8/ScriptWrappable.h"
     30 #include "core/html/HTMLCanvasElement.h"
     31 #include "wtf/HashSet.h"
     32 #include "wtf/Noncopyable.h"
     33 #include "wtf/text/StringHash.h"
     34 
     35 namespace blink { class WebLayer; }
     36 
     37 namespace WebCore {
     38 
     39 class CanvasPattern;
     40 class HTMLCanvasElement;
     41 class HTMLImageElement;
     42 class HTMLVideoElement;
     43 class KURL;
     44 class WebGLObject;
     45 
     46 class CanvasRenderingContext : public ScriptWrappable {
     47     WTF_MAKE_NONCOPYABLE(CanvasRenderingContext); WTF_MAKE_FAST_ALLOCATED;
     48 public:
     49     virtual ~CanvasRenderingContext() { }
     50 
     51     void ref() { m_canvas->ref(); }
     52     void deref() { m_canvas->deref(); }
     53     HTMLCanvasElement* canvas() const { return m_canvas; }
     54 
     55     virtual bool is2d() const { return false; }
     56     virtual bool is3d() const { return false; }
     57     virtual bool isAccelerated() const { return false; }
     58     virtual bool hasAlpha() const { return true; }
     59 
     60     virtual void paintRenderingResultsToCanvas() {}
     61 
     62     virtual blink::WebLayer* platformLayer() const { return 0; }
     63 
     64 protected:
     65     CanvasRenderingContext(HTMLCanvasElement*);
     66     bool wouldTaintOrigin(const CanvasPattern*);
     67     bool wouldTaintOrigin(const HTMLCanvasElement*);
     68     bool wouldTaintOrigin(const HTMLImageElement*);
     69     bool wouldTaintOrigin(const HTMLVideoElement*);
     70     bool wouldTaintOrigin(const KURL&);
     71 
     72     template<class T> void checkOrigin(const T* arg)
     73     {
     74         if (wouldTaintOrigin(arg))
     75             canvas()->setOriginTainted();
     76     }
     77     void checkOrigin(const KURL&);
     78 
     79 private:
     80     HTMLCanvasElement* m_canvas;
     81     HashSet<String> m_cleanURLs;
     82 };
     83 
     84 } // namespace WebCore
     85 
     86 #endif
     87