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      1 // Copyright (C) 2013 Google Inc. All rights reserved.
      2 //
      3 // Redistribution and use in source and binary forms, with or without
      4 // modification, are permitted provided that the following conditions are
      5 // met:
      6 //
      7 //    * Redistributions of source code must retain the above copyright
      8 // notice, this list of conditions and the following disclaimer.
      9 //    * Redistributions in binary form must reproduce the above
     10 // copyright notice, this list of conditions and the following disclaimer
     11 // in the documentation and/or other materials provided with the
     12 // distribution.
     13 //    * Neither the name of Google Inc. nor the names of its
     14 // contributors may be used to endorse or promote products derived from
     15 // this software without specific prior written permission.
     16 //
     17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     28 
     29 #ifndef GraphicsContextStateSaver_h
     30 #define GraphicsContextStateSaver_h
     31 
     32 #include "platform/PlatformExport.h"
     33 #include "platform/graphics/GraphicsContext.h"
     34 
     35 namespace WebCore {
     36 
     37 class PLATFORM_EXPORT GraphicsContextStateSaver {
     38     WTF_MAKE_FAST_ALLOCATED;
     39 public:
     40     GraphicsContextStateSaver(GraphicsContext& context, bool saveAndRestore = true)
     41         : m_context(context)
     42         , m_saveAndRestore(saveAndRestore)
     43     {
     44         if (m_saveAndRestore)
     45             m_context.save();
     46     }
     47 
     48     ~GraphicsContextStateSaver()
     49     {
     50         if (m_saveAndRestore)
     51             m_context.restore();
     52     }
     53 
     54     void save()
     55     {
     56         ASSERT(!m_saveAndRestore);
     57         m_context.save();
     58         m_saveAndRestore = true;
     59     }
     60 
     61     void restore()
     62     {
     63         ASSERT(m_saveAndRestore);
     64         m_context.restore();
     65         m_saveAndRestore = false;
     66     }
     67 
     68     GraphicsContext* context() const { return &m_context; }
     69     bool saved() const { return m_saveAndRestore; }
     70 
     71 private:
     72     GraphicsContext& m_context;
     73     bool m_saveAndRestore;
     74 };
     75 
     76 } // namespace WebCore
     77 
     78 #endif // GraphicsContextStateSaver_h
     79