Redesigned CommandBuffer and NPDevice3D interfaces

gpu/command_buffer/common/command_buffer.h

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_
 #define GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_
 
 #include "base/basictypes.h"
 #include "gpu/command_buffer/common/buffer.h"
+#include "gpu/command_buffer/common/constants.h"
 
 namespace gpu {
 
 // Common interface for CommandBuffer implementations.
 class CommandBuffer {
  public:
+  struct State {
+    State()
+        : size(0),
+          get_offset(0),
+          put_offset(0),
+          token(-1),
+          error(parse_error::kParseNoError) {
+    }
+
+    // Size of the command buffer in command buffer entries.
+    int32 size;
+
+    // The offset (in entries) from which the reader is reading.
+    int32 get_offset;
+
+    // The offset (in entries) at which the writer is writing.
+    int32 put_offset;
+
+    // The current token value. This is used by the writer to defer
+    // changes to shared memory objects until the reader has reached a certain
+    // point in the command buffer. The reader is responsible for updating the
+    // token value, for example in response to an asynchronous set token command
+    // embedded in the command buffer. The default token value is zero.
+    int32 token;
+
+    // Error status.
+    parse_error::ParseError error;
+  };
+
   CommandBuffer() {
   }
 
   virtual ~CommandBuffer() {
   }
 
   // Initialize the command buffer with the given size (number of command
   // entries).
   virtual bool Initialize(int32 size) = 0;
 
   // Gets the ring buffer for the command buffer.
   virtual Buffer GetRingBuffer() = 0;
 
-  virtual int32 GetSize() = 0;
+  // Returns the current status.
+  virtual State GetState() = 0;
 
   // The writer calls this to update its put offset. This function returns the
   // reader's most recent get offset. Does not return until after the put offset
   // change callback has been invoked. Returns -1 if the put offset is invalid.
-  virtual int32 SyncOffsets(int32 put_offset) = 0;
-
-  // Returns the current get offset. This can be called from any thread.
-  virtual int32 GetGetOffset() = 0;
+  virtual State Flush(int32 put_offset) = 0;
 
   // Sets the current get offset. This can be called from any thread.
   virtual void SetGetOffset(int32 get_offset) = 0;
 
-  // Returns the current put offset. This can be called from any thread.
-  virtual int32 GetPutOffset() = 0;
-
   // Create a transfer buffer and return a handle that uniquely
   // identifies it or -1 on error.
   virtual int32 CreateTransferBuffer(size_t size) = 0;
 
   // Destroy a transfer buffer and recycle the handle.
   virtual void DestroyTransferBuffer(int32 id) = 0;
 
   // Get the transfer buffer associated with a handle.
   virtual Buffer GetTransferBuffer(int32 handle) = 0;
 
-  // Get the current token value. This is used for by the writer to defer
-  // changes to shared memory objects until the reader has reached a certain
-  // point in the command buffer. The reader is responsible for updating the
-  // token value, for example in response to an asynchronous set token command
-  // embedded in the command buffer. The default token value is zero.
-  virtual int32 GetToken() = 0;
-
   // Allows the reader to update the current token value.
   virtual void SetToken(int32 token) = 0;
 
-  // Get the current parse error and reset it to zero. Zero means no error. Non-
-  // zero means error. The default error status is zero.
-  virtual int32 ResetParseError() = 0;
-
   // Allows the reader to set the current parse error.
-  virtual void SetParseError(int32 parse_error) = 0;
-
-  // Returns whether the command buffer is in the error state.
-  virtual bool GetErrorStatus() = 0;
-
-  // Allows the reader to set the error status. Once in an error state, the
-  // command buffer cannot recover and ceases to process commands.
-  virtual void RaiseErrorStatus() = 0;
+  virtual void SetParseError(parse_error::ParseError) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CommandBuffer);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_