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   static const int kParseCommandsSlice = 20;
  23
  24   explicit CommandParser(AsyncAPIInterface* handler);
  25
  26   // Sets the buffer to read commands from.
  27   void SetBuffer(
  28       void* shm_address,
  29       size_t shm_size,
  30       ptrdiff_t offset,
  31       size_t size);
  32
  33   // Gets the "get" pointer. The get pointer is an index into the command
  34   // buffer considered as an array of CommandBufferEntry.
  35   CommandBufferOffset get() const { return get_; }
  36
  37   // Sets the "get" pointer. The get pointer is an index into the command buffer
  38   // considered as an array of CommandBufferEntry.
  39   bool set_get(CommandBufferOffset get) {
  40     if (get >= 0 && get < entry_count_) {
  41       get_ = get;
  42       return true;
  43     }
  44     return false;
  45   }
  46
  47   // Sets the "put" pointer. The put pointer is an index into the command
  48   // buffer considered as an array of CommandBufferEntry.
  49   void set_put(CommandBufferOffset put) { put_ = put; }
  50
  51   // Gets the "put" pointer. The put pointer is an index into the command
  52   // buffer considered as an array of CommandBufferEntry.
  53   CommandBufferOffset put() const { return put_; }
  54
  55   // Checks whether there are commands to process.
  56   bool IsEmpty() const { return put_ == get_; }
  57
  58   // Processes one command, updating the get pointer. This will return an error
  59   // if there are no commands in the buffer.
  60   error::Error ProcessCommands(int num_commands);
  61
  62   // Processes all commands until get == put.
  63   error::Error ProcessAllCommands();
  64
  65  private:
  66   CommandBufferOffset get_;
  67   CommandBufferOffset put_;
  68   CommandBufferEntry* buffer_;
  69   int32 entry_count_;
  70   AsyncAPIInterface* handler_;
  71 };
  72
  73 // This class defines the interface for an asynchronous API handler, that
  74 // is responsible for de-multiplexing commands and their arguments.
  75 class GPU_EXPORT AsyncAPIInterface {
  76  public:
  77   AsyncAPIInterface() {}
  78   virtual ~AsyncAPIInterface() {}
  79
  80   // Executes a single command.
  81   // Parameters:
  82   //    command: the command index.
  83   //    arg_count: the number of CommandBufferEntry arguments.
  84   //    cmd_data: the command data.
  85   // Returns:
  86   //   error::kNoError if no error was found, one of
  87   //   error::Error otherwise.
  88   virtual error::Error DoCommand(
  89       unsigned int command,
  90       unsigned int arg_count,
  91       const void* cmd_data) = 0;
  92
  93   // Executes multiple commands.
  94   // Parameters:
  95   //    num_commands: maximum number of commands to execute from buffer.
  96   //    buffer: pointer to first command entry to process.
  97   //    num_entries: number of sequential command buffer entries in buffer.
  98   //    entries_processed: if not 0, is set to the number of entries processed.
  99   virtual error::Error DoCommands(unsigned int num_commands,
 100                                   const void* buffer,
 101                                   int num_entries,
 102                                   int* entries_processed);
 103
 104   // Returns a name for a command. Useful for logging / debuging.
 105   virtual const char* GetCommandName(unsigned int command_id) const = 0;
 106 };
 107
 108 }  // namespace gpu
 109
 110 #endif  // GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_