Use shared memory to update the renderer's view of the command buffer state.

gpu/command_buffer/service/command_buffer_service.cc

 // Copyright (c) 2012 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.
 
 #include "gpu/command_buffer/service/command_buffer_service.h"
 
 #include <limits>
 
 #include "base/process_util.h"
 #include "base/debug/trace_event.h"
 #include "gpu/command_buffer/common/cmd_buffer_common.h"
+#include "gpu/command_buffer/common/command_buffer_shared.h"
 
 using ::base::SharedMemory;
 
 namespace gpu {
 
 CommandBufferService::CommandBufferService()
     : ring_buffer_id_(-1),
+      shared_state_(NULL),
       num_entries_(0),
       get_offset_(0),
       put_offset_(0),
       token_(0),
       generation_(0),
       error_(error::kNoError),
       context_lost_reason_(error::kUnknown),
       shared_memory_bytes_allocated_(0) {
   // Element zero is always NULL.
   registered_objects_.push_back(Buffer());
@@ skipping 23 matching lines @@
   state.context_lost_reason = context_lost_reason_;
   state.generation = ++generation_;
 
   return state;
 }
 
 CommandBufferService::State CommandBufferService::GetLastState() {
   return GetState();
 }
 
+void CommandBufferService::UpdateState() {
+  if (shared_state_) {
+    CommandBufferService::State state = GetState();
+    shared_state_->Write(state);
+  }
+}
+
 CommandBufferService::State CommandBufferService::FlushSync(
     int32 put_offset, int32 last_known_get) {
   if (put_offset < 0 || put_offset > num_entries_) {
     error_ = gpu::error::kOutOfBounds;
     return GetState();
   }
 
   put_offset_ = put_offset;
 
   if (!put_offset_change_callback_.is_null())
@@ skipping 19 matching lines @@
   DCHECK_EQ(put_offset_, get_offset_);  // Only if it's empty.
   ring_buffer_ = GetTransferBuffer(transfer_buffer_id);
   DCHECK(ring_buffer_.ptr);
   ring_buffer_id_ = transfer_buffer_id;
   num_entries_ = ring_buffer_.size / sizeof(CommandBufferEntry);
   put_offset_ = 0;
   SetGetOffset(0);
   if (!get_buffer_change_callback_.is_null()) {
     get_buffer_change_callback_.Run(ring_buffer_id_);
   }
+
+  UpdateState();
+}
+
+void CommandBufferService::SetSharedStateBuffer(int32 transfer_buffer_id) {
+  gpu::Buffer buffer = GetTransferBuffer(transfer_buffer_id);
+  shared_state_ = reinterpret_cast<CommandBufferSharedState*>(buffer.ptr);
+
+  UpdateState();
 }
 
 void CommandBufferService::SetGetOffset(int32 get_offset) {
   DCHECK(get_offset >= 0 && get_offset < num_entries_);
   get_offset_ = get_offset;
 }
 
 int32 CommandBufferService::CreateTransferBuffer(size_t size,
                                                  int32 id_request) {
   SharedMemory buffer;
@@ skipping 141 matching lines @@
     const GetBufferChangedCallback& callback) {
   get_buffer_change_callback_ = callback;
 }
 
 void CommandBufferService::SetParseErrorCallback(
     const base::Closure& callback) {
   parse_error_callback_ = callback;
 }
 
 }  // namespace gpu