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      1 // Copyright (c) 2012 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 GPU_COMMAND_BUFFER_SERVICE_COMMAND_BUFFER_SERVICE_H_
      6 #define GPU_COMMAND_BUFFER_SERVICE_COMMAND_BUFFER_SERVICE_H_
      7 
      8 #include "base/callback.h"
      9 #include "base/memory/shared_memory.h"
     10 #include "gpu/command_buffer/common/command_buffer.h"
     11 #include "gpu/command_buffer/common/command_buffer_shared.h"
     12 
     13 namespace gpu {
     14 
     15 class TransferBufferManagerInterface;
     16 
     17 class GPU_EXPORT CommandBufferServiceBase : public CommandBuffer {
     18  public:
     19   // Sets the current get offset. This can be called from any thread.
     20   virtual void SetGetOffset(int32 get_offset) = 0;
     21 
     22   // Get the transfer buffer associated with an ID. Returns a null buffer for
     23   // ID 0.
     24   virtual scoped_refptr<gpu::Buffer> GetTransferBuffer(int32 id) = 0;
     25 
     26   // Allows the reader to update the current token value.
     27   virtual void SetToken(int32 token) = 0;
     28 
     29   // Allows the reader to set the current parse error.
     30   virtual void SetParseError(error::Error) = 0;
     31 
     32   // Allows the reader to set the current context lost reason.
     33   // NOTE: if calling this in conjunction with SetParseError,
     34   // call this first.
     35   virtual void SetContextLostReason(error::ContextLostReason) = 0;
     36 };
     37 
     38 // An object that implements a shared memory command buffer and a synchronous
     39 // API to manage the put and get pointers.
     40 class GPU_EXPORT CommandBufferService : public CommandBufferServiceBase {
     41  public:
     42   typedef base::Callback<bool(int32)> GetBufferChangedCallback;
     43   explicit CommandBufferService(
     44       TransferBufferManagerInterface* transfer_buffer_manager);
     45   virtual ~CommandBufferService();
     46 
     47   // CommandBuffer implementation:
     48   virtual bool Initialize() OVERRIDE;
     49   virtual State GetLastState() OVERRIDE;
     50   virtual int32 GetLastToken() OVERRIDE;
     51   virtual void Flush(int32 put_offset) OVERRIDE;
     52   virtual void WaitForTokenInRange(int32 start, int32 end) OVERRIDE;
     53   virtual void WaitForGetOffsetInRange(int32 start, int32 end) OVERRIDE;
     54   virtual void SetGetBuffer(int32 transfer_buffer_id) OVERRIDE;
     55   virtual scoped_refptr<Buffer> CreateTransferBuffer(size_t size,
     56                                                      int32* id) OVERRIDE;
     57   virtual void DestroyTransferBuffer(int32 id) OVERRIDE;
     58 
     59   // CommandBufferServiceBase implementation:
     60   virtual void SetGetOffset(int32 get_offset) OVERRIDE;
     61   virtual scoped_refptr<Buffer> GetTransferBuffer(int32 id) OVERRIDE;
     62   virtual void SetToken(int32 token) OVERRIDE;
     63   virtual void SetParseError(error::Error error) OVERRIDE;
     64   virtual void SetContextLostReason(error::ContextLostReason) OVERRIDE;
     65 
     66   // Sets a callback that is called whenever the put offset is changed. When
     67   // called with sync==true, the callback must not return until some progress
     68   // has been made (unless the command buffer is empty), i.e. the get offset
     69   // must have changed. It need not process the entire command buffer though.
     70   // This allows concurrency between the writer and the reader while giving the
     71   // writer a means of waiting for the reader to make some progress before
     72   // attempting to write more to the command buffer. Takes ownership of
     73   // callback.
     74   virtual void SetPutOffsetChangeCallback(const base::Closure& callback);
     75   // Sets a callback that is called whenever the get buffer is changed.
     76   virtual void SetGetBufferChangeCallback(
     77       const GetBufferChangedCallback& callback);
     78   virtual void SetParseErrorCallback(const base::Closure& callback);
     79 
     80   // Setup the shared memory that shared state should be copied into.
     81   void SetSharedStateBuffer(scoped_ptr<BufferBacking> shared_state_buffer);
     82 
     83   // Copy the current state into the shared state transfer buffer.
     84   void UpdateState();
     85 
     86   // Registers an existing shared memory object and get an ID that can be used
     87   // to identify it in the command buffer.
     88   bool RegisterTransferBuffer(int32 id, scoped_ptr<BufferBacking> buffer);
     89 
     90  private:
     91   int32 ring_buffer_id_;
     92   scoped_refptr<Buffer> ring_buffer_;
     93   scoped_ptr<BufferBacking> shared_state_buffer_;
     94   CommandBufferSharedState* shared_state_;
     95   int32 num_entries_;
     96   int32 get_offset_;
     97   int32 put_offset_;
     98   base::Closure put_offset_change_callback_;
     99   GetBufferChangedCallback get_buffer_change_callback_;
    100   base::Closure parse_error_callback_;
    101   TransferBufferManagerInterface* transfer_buffer_manager_;
    102   int32 token_;
    103   uint32 generation_;
    104   error::Error error_;
    105   error::ContextLostReason context_lost_reason_;
    106 
    107   DISALLOW_COPY_AND_ASSIGN(CommandBufferService);
    108 };
    109 
    110 }  // namespace gpu
    111 
    112 #endif  // GPU_COMMAND_BUFFER_SERVICE_COMMAND_BUFFER_SERVICE_H_
    113