Refactor CommandBufferHelper to use Jump to loop...

gpu/command_buffer/service/cmd_parser.cc

 // 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.
 
 // This file contains the implementation of the command parser.
 
 #include "gpu/command_buffer/service/cmd_parser.h"
 
 namespace gpu {
 
@@ skipping 40 matching lines @@
   }
 
   error::Error result = handler_->DoCommand(
       header.command, header.size - 1, buffer_ + get);
   // TODO(gman): If you want to log errors this is the best place to catch them.
   //     It seems like we need an official way to turn on a debug mode and
   //     get these errors.
   if (result != error::kNoError) {
     ReportError(header.command, result);
   }
-  get_ = (get + header.size) % entry_count_;
+
+  // If get was not set somewhere else advance it.
+  if (get == get_) {
+    get_ = (get + header.size) % entry_count_;
+  }
   return result;
 }
 
 void CommandParser::ReportError(unsigned int command_id,
                                 error::Error result) {
   DLOG(INFO) << "Error: " << result << " for Command "
              << handler_->GetCommandName(command_id);
 }
 
 // Processes all the commands, while the buffer is not empty. Stop if an error
 // is encountered.
 error::Error CommandParser::ProcessAllCommands() {
   while (!IsEmpty()) {
     error::Error error = ProcessCommand();
     if (error) return error;
   }
   return error::kNoError;
 }
 
 }  // namespace gpu