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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef UI_GFX_GPU_MEMORY_BUFFER_H_
      6 #define UI_GFX_GPU_MEMORY_BUFFER_H_
      7 
      8 #include "base/memory/shared_memory.h"
      9 #include "build/build_config.h"
     10 #include "ui/gfx/gfx_export.h"
     11 
     12 #if defined(OS_ANDROID)
     13 #include <third_party/khronos/EGL/egl.h>
     14 #endif
     15 
     16 namespace gfx {
     17 
     18 enum GpuMemoryBufferType {
     19   EMPTY_BUFFER,
     20   SHARED_MEMORY_BUFFER,
     21   EGL_CLIENT_BUFFER,
     22   IO_SURFACE_BUFFER
     23 };
     24 
     25 struct GpuMemoryBufferHandle {
     26   GpuMemoryBufferHandle()
     27       : type(EMPTY_BUFFER),
     28         handle(base::SharedMemory::NULLHandle())
     29 #if defined(OS_ANDROID)
     30         , native_buffer(NULL)
     31 #endif
     32 #if defined(OS_MACOSX)
     33         , io_surface_id(0)
     34 #endif
     35   {
     36   }
     37   bool is_null() const { return type == EMPTY_BUFFER; }
     38   GpuMemoryBufferType type;
     39   base::SharedMemoryHandle handle;
     40 #if defined(OS_ANDROID)
     41   EGLClientBuffer native_buffer;
     42 #endif
     43 #if defined(OS_MACOSX)
     44   uint32 io_surface_id;
     45 #endif
     46 
     47 };
     48 
     49 // Interface for creating and accessing a zero-copy GPU memory buffer.
     50 // This design evolved from the generalization of GraphicBuffer API
     51 // of Android framework.
     52 //
     53 // THREADING CONSIDERATIONS:
     54 //
     55 // This interface is thread-safe. However, multiple threads mapping
     56 // a buffer for Write or ReadOrWrite simultaneously may result in undefined
     57 // behavior and is not allowed.
     58 class GFX_EXPORT GpuMemoryBuffer {
     59  public:
     60   enum AccessMode {
     61     READ_ONLY,
     62     WRITE_ONLY,
     63     READ_WRITE,
     64   };
     65 
     66   GpuMemoryBuffer();
     67   virtual ~GpuMemoryBuffer();
     68 
     69   // Maps the buffer so the client can write the bitmap data in |*vaddr|
     70   // subsequently. This call may block, for instance if the hardware needs
     71   // to finish rendering or if CPU caches need to be synchronized.
     72   virtual void Map(AccessMode mode, void** vaddr) = 0;
     73 
     74   // Unmaps the buffer. Called after all changes to the buffer are
     75   // completed.
     76   virtual void Unmap() = 0;
     77 
     78   // Returns true iff the buffer is mapped.
     79   virtual bool IsMapped() const = 0;
     80 
     81   // Returns the stride in bytes for the buffer.
     82   virtual uint32 GetStride() const = 0;
     83 
     84   // Returns a platform specific handle for this buffer.
     85   virtual GpuMemoryBufferHandle GetHandle() const = 0;
     86 };
     87 
     88 }  // namespace gfx
     89 
     90 #endif  // UI_GFX_GPU_MEMORY_BUFFER_H_
     91