gpu/command_buffer/service/cmd_parser.h

   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 // This file contains the command parser class.
   6
   7 #ifndef GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_
   8 #define GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_
   9
  10 #include "gpu/command_buffer/common/constants.h"
  11 #include "gpu/command_buffer/common/cmd_buffer_common.h"
  12 #include "gpu/gpu_export.h"
  13
  14 namespace gpu {
  15
  16 class AsyncAPIInterface;
  17
  18 // Command parser class. This class parses commands from a shared memory
  19 // buffer, to implement some asynchronous RPC mechanism.
  20 class GPU_EXPORT CommandParser {
  21  public:
  22   explicit CommandParser(AsyncAPIInterface* handler);
  23
  24   // Sets the buffer to read commands from.
  25   void SetBuffer(
  26       void* shm_address,
  27       size_t shm_size,
  28       ptrdiff_t offset,
  29       size_t size);
  30
  31   // Gets the "get" pointer. The get pointer is an index into the command
  32   // buffer considered as an array of CommandBufferEntry.
  33   CommandBufferOffset get() const { return get_; }
  34
  35   // Sets the "get" pointer. The get pointer is an index into the command buffer
  36   // considered as an array of CommandBufferEntry.
  37   bool set_get(CommandBufferOffset get) {
  38     if (get >= 0 && get < entry_count_) {
  39       get_ = get;
  40       return true;
  41     }
  42     return false;
  43   }
  44
  45   // Sets the "put" pointer. The put pointer is an index into the command
  46   // buffer considered as an array of CommandBufferEntry.
  47   void set_put(CommandBufferOffset put) { put_ = put; }
  48
  49   // Gets the "put" pointer. The put pointer is an index into the command
  50   // buffer considered as an array of CommandBufferEntry.
  51   CommandBufferOffset put() const { return put_; }
  52
  53   // Checks whether there are commands to process.
  54   bool IsEmpty() const { return put_ == get_; }
  55
  56   // Processes one command, updating the get pointer. This will return an error
  57   // if there are no commands in the buffer.
  58   error::Error ProcessCommand();
  59
  60   // Processes all commands until get == put.
  61   error::Error ProcessAllCommands();
  62
  63   // Reports an error.
  64   void ReportError(unsigned int command_id, error::Error result);
  65
  66  private:
  67   CommandBufferOffset get_;
  68   CommandBufferOffset put_;
  69   CommandBufferEntry* buffer_;
  70   int32 entry_count_;
  71   AsyncAPIInterface* handler_;
  72 };
  73
  74 // This class defines the interface for an asynchronous API handler, that
  75 // is responsible for de-multiplexing commands and their arguments.
  76 class AsyncAPIInterface {
  77  public:
  78   AsyncAPIInterface() {}
  79   virtual ~AsyncAPIInterface() {}
  80
  81   // Executes a command.
  82   // Parameters:
  83   //    command: the command index.
  84   //    arg_count: the number of CommandBufferEntry arguments.
  85   //    cmd_data: the command data.
  86   // Returns:
  87   //   error::kNoError if no error was found, one of
  88   //   error::Error otherwise.
  89   virtual error::Error DoCommand(
  90       unsigned int command,
  91       unsigned int arg_count,
  92       const void* cmd_data) = 0;
  93
  94   // Returns a name for a command. Useful for logging / debuging.
  95   virtual const char* GetCommandName(unsigned int command_id) const = 0;
  96 };
  97
  98 }  // namespace gpu
  99
 100 #endif  // GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_