Rework FlushSync to return early if commands have been processed since the last update

webkit/plugins/ppapi/ppb_context_3d_impl.cc

 // Copyright (c) 2011 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 "webkit/plugins/ppapi/ppb_context_3d_impl.h"
 
 #include "base/logging.h"
 #include "base/shared_memory.h"
 #include "gpu/command_buffer/client/gles2_cmd_helper.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
@@ skipping 28 matching lines @@
     *shm_size = size;
     return true;
 }
 
 PP_Context3DTrustedState PPStateFromGPUState(gpu::CommandBuffer::State s) {
   PP_Context3DTrustedState state = {
       s.num_entries,
       s.get_offset,
       s.put_offset,
       s.token,
-      static_cast<PPB_Context3DTrustedError>(s.error)
+      static_cast<PPB_Context3DTrustedError>(s.error),
+      s.generation
   };
   return state;
 }
 
 PP_Resource Create(PP_Instance instance_id,
                    PP_Config3D_Dev config,
                    PP_Resource share_context,
                    const int32_t* attrib_list) {
   // TODO(alokp): Support shared context.
   DCHECK_EQ(0, share_context);
@@ skipping 124 matching lines @@
 }
 
 PP_Context3DTrustedState FlushSync(PP_Resource context_id, int32_t put_offset) {
   scoped_refptr<PPB_Context3D_Impl> context(
       Resource::GetAs<PPB_Context3D_Impl>(context_id));
   if (!context.get() || !context->command_buffer()) {
     PP_Context3DTrustedState error_state = { 0 };
     return error_state;
   }
 
-  return PPStateFromGPUState(context->command_buffer()->FlushSync(put_offset));
+  gpu::CommandBuffer::State state = context->command_buffer()->GetState();
+  return PPStateFromGPUState(
+      context->command_buffer()->FlushSync(put_offset, state.get_offset));
 }
 
 int32_t CreateTransferBuffer(PP_Resource context_id, uint32_t size) {
   scoped_refptr<PPB_Context3D_Impl> context(
       Resource::GetAs<PPB_Context3D_Impl>(context_id));
   if (!context.get() || !context->command_buffer())
     return 0;
   return context->command_buffer()->CreateTransferBuffer(size, -1);
 }
 
@@ skipping 13 matching lines @@
   scoped_refptr<PPB_Context3D_Impl> context(
       Resource::GetAs<PPB_Context3D_Impl>(context_id));
   if (!context.get() || !context->command_buffer())
     return PP_FALSE;
   gpu::Buffer buffer = context->command_buffer()->GetTransferBuffer(id);
 
   return ShmToHandle(buffer.shared_memory, buffer.size, shm_handle, shm_size)
       ? PP_TRUE : PP_FALSE;
 }
 
+PP_Context3DTrustedState FlushSyncFast(
+    PP_Resource context_id, int32_t put_offset, int32 last_known_get) {
+  scoped_refptr<PPB_Context3D_Impl> context(
+      Resource::GetAs<PPB_Context3D_Impl>(context_id));
+  if (!context.get() || !context->command_buffer()) {
+    PP_Context3DTrustedState error_state = { 0 };
+    return error_state;
+  }
+
+  return PPStateFromGPUState(
+      context->command_buffer()->FlushSync(put_offset, last_known_get));
+}
 }  // namespace
 
 PPB_Context3D_Impl::PPB_Context3D_Impl(PluginInstance* instance)
     : Resource(instance),
       instance_(instance),
       transfer_buffer_id_(0),
       draw_surface_(NULL),
       read_surface_(NULL),
       callback_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
 }
 
 PPB_Context3D_Impl::~PPB_Context3D_Impl() {
   Destroy();
 }
 
 const PPB_Context3D_Dev* PPB_Context3D_Impl::GetInterface() {
   return &ppb_context3d;
 }
 
 const PPB_Context3DTrusted_Dev* PPB_Context3D_Impl::GetTrustedInterface() {
   static const PPB_Context3DTrusted_Dev iface = {
     &CreateRaw,
     &Initialize,
     &GetRingBuffer,
     &GetState,
     &Flush,
     &FlushSync,
     &CreateTransferBuffer,
     &DestroyTransferBuffer,
-    &GetTransferBuffer
+    &GetTransferBuffer,
+    &FlushSyncFast,
   };
   return &iface;
 }
 
 PPB_Context3D_Impl* PPB_Context3D_Impl::AsPPB_Context3D_Impl() {
   return this;
 }
 
 bool PPB_Context3D_Impl::InitRaw(PP_Config3D_Dev config,
                                  PP_Resource share_context,
@@ skipping 108 matching lines @@
     read_surface_->OnContextLost();
 }
 
 gpu::CommandBuffer *PPB_Context3D_Impl::command_buffer() {
   return platform_context_.get() ? platform_context_->GetCommandBuffer() : NULL;
 }
 
 }  // namespace ppapi
 }  // namespace webkit