Added an extra sync token field for extra command buffer identification.

gpu/command_buffer/common/sync_token.h

 // Copyright 2015 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.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_SYNC_TOKEN_H_
 #define GPU_COMMAND_BUFFER_COMMON_SYNC_TOKEN_H_
 
 #include <stdint.h>
 #include <string.h>
 
 #include "gpu/command_buffer/common/constants.h"
 #include "gpu/gpu_export.h"
 
 // From glextchromium.h.
 #ifndef GL_SYNC_TOKEN_SIZE_CHROMIUM
 #define GL_SYNC_TOKEN_SIZE_CHROMIUM 24
 #endif
 
 namespace gpu {
 
 // A Sync Token is a binary blob which represents a waitable fence sync
 // on a particular command buffer namespace and id.
 // See src/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt for more
 // details.
 struct GPU_EXPORT SyncToken {
   SyncToken()
       : verified_flush_(false),
         namespace_id_(CommandBufferNamespace::INVALID),
+        extra_data_field_(0),
         command_buffer_id_(0),
         release_count_(0) {}
 
   // TODO(dyen): This is an intermediate conversion constructor while we
   // are converting from the old sync point system. Remove once conversion
   // is finished.
   explicit SyncToken(uint32_t sync_point)
       : verified_flush_(sync_point ? true : false),
         namespace_id_(sync_point ? gpu::CommandBufferNamespace::OLD_SYNC_POINTS
                                  : gpu::CommandBufferNamespace::INVALID),
+        extra_data_field_(0),
         command_buffer_id_(0),
         release_count_(sync_point) {}
 
   SyncToken(CommandBufferNamespace namespace_id,
+            int32_t extra_data_field,
             uint64_t command_buffer_id,
             uint64_t release_count)
       : verified_flush_(false),
         namespace_id_(namespace_id),
+        extra_data_field_(extra_data_field),
         command_buffer_id_(command_buffer_id),
         release_count_(release_count) {}
 
   void Set(CommandBufferNamespace namespace_id,
+           int32_t extra_data_field,
            uint64_t command_buffer_id,
            uint64_t release_count) {
     namespace_id_ = namespace_id;
+    extra_data_field_ = extra_data_field;
     command_buffer_id_ = command_buffer_id;
     release_count_ = release_count;
   }
 
   void Clear() {
     verified_flush_ = false;
     namespace_id_ = CommandBufferNamespace::INVALID;
+    extra_data_field_ = 0;
     command_buffer_id_ = 0;
     release_count_ = 0;
   }
 
   void SetVerifyFlush() {
     verified_flush_ = true;
   }
 
   bool HasData() const {
     return namespace_id_ != CommandBufferNamespace::INVALID;
   }
 
   int8_t* GetData() { return reinterpret_cast<int8_t*>(this); }
 
   const int8_t* GetConstData() const {
     return reinterpret_cast<const int8_t*>(this);
   }
 
   bool verified_flush() const { return verified_flush_; }
   CommandBufferNamespace namespace_id() const { return namespace_id_; }
   uint64_t command_buffer_id() const { return command_buffer_id_; }
   uint64_t release_count() const { return release_count_; }
 
+  // This extra data field can be used by command buffers to add extra
+  // information to identify unverified sync tokens. The current purpose
+  // of this field is only for unverified sync tokens which only exist within
+  // the same process so this information will not survive cross-process IPCs.
+  int32_t extra_data_field() const { return extra_data_field_; }
+
   bool operator<(const SyncToken& other) const {
     // TODO(dyen): Once all our compilers support c++11, we can replace this
     // long list of comparisons with std::tie().
     return (namespace_id_ < other.namespace_id()) ||
            ((namespace_id_ == other.namespace_id()) &&
             ((command_buffer_id_ < other.command_buffer_id()) ||
              ((command_buffer_id_ == other.command_buffer_id()) &&
               (release_count_ < other.release_count()))));
   }
 
   bool operator==(const SyncToken& other) const {
     return verified_flush_ == other.verified_flush() &&
            namespace_id_ == other.namespace_id() &&
+           extra_data_field_ == other.extra_data_field() &&
            command_buffer_id_ == other.command_buffer_id() &&
            release_count_ == other.release_count();
   }
 
   bool operator!=(const SyncToken& other) const { return !(*this == other); }
 
  private:
   bool verified_flush_;
   CommandBufferNamespace namespace_id_;
+  int32_t extra_data_field_;
   uint64_t command_buffer_id_;
   uint64_t release_count_;
 };
 
 static_assert(sizeof(SyncToken) <= GL_SYNC_TOKEN_SIZE_CHROMIUM,
               "SyncToken size must not exceed GL_SYNC_TOKEN_SIZE_CHROMIUM");
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_SYNC_TOKEN_H_