sync: Implement NonBlockingTypeProcessorCore

sync/engine/non_blocking_sync_common.h

 // Copyright 2014 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 SYNC_ENGINE_NON_BLOCKING_SYNC_COMMON_H_
 #define SYNC_ENGINE_NON_BLOCKING_SYNC_COMMON_H_
 
 #include <string>
 #include <vector>
 
 #include "base/time/time.h"
 #include "sync/base/sync_export.h"
 #include "sync/protocol/sync.pb.h"
 
 namespace syncer {
 
+static const int64 kUncommittedVersion = -1;
+
 // Data-type global state that must be accessed and updated on the sync thread,
 // but persisted on or through the model thread.
 struct SYNC_EXPORT_PRIVATE DataTypeState {
   DataTypeState();
   ~DataTypeState();
 
   // The latest progress markers received from the server.
   sync_pb::DataTypeProgressMarker progress_marker;
 
   // A data type context.  Sent to the server in every commit or update
   // request.  May be updated by either by responses from the server or
   // requests made on the model thread.  The interpretation of this value may
   // be data-type specific.  Many data types ignore it.
   sync_pb::DataTypeContext type_context;
 
   // The ID of the folder node that sits at the top of this type's folder
   // hierarchy.  We keep this around for legacy reasons.  The protocol expects
   // that all nodes of a certain type are children of the same type root
   // entity.  This entity is delivered by the server, and may not be available
   // until the first download cycle has completed.
   std::string type_root_id;
 
   // A strictly increasing counter used to generate unique values for the
   // client-assigned IDs.  The incrementing and ID assignment happens on the
   // sync thread, but we store the value here so we can pass it back to the
   // model thread for persistence.  This is probably unnecessary for the
   // client-tagged data types supported by non-blocking sync, but we will
   // continue to emulate the directory sync's behavior for now.
   int64 next_client_id;
+
+  // This flag is set to true when the first download cycle is complete.  The
+  // model thread should not attempt to commit any items until this flag is

[Nicolas Zea, 2014/06/02 20:27:17]

nit: prefer referring to NonBlockingTypeProcessor directly, rather than just
model thread

[rlarocque, 2014/06/02 21:39:14]

Done.

+  // set.
+  bool initial_sync_done;
 };
 
 struct SYNC_EXPORT_PRIVATE CommitRequestData {
   CommitRequestData();
   ~CommitRequestData();
 
   std::string id;
   std::string client_tag_hash;
 
   // Strictly incrementing number for in-progress commits.  More information
@@ skipping 33 matching lines @@
   sync_pb::EntitySpecifics specifics;
 };
 
 typedef std::vector<CommitRequestData> CommitRequestDataList;
 typedef std::vector<CommitResponseData> CommitResponseDataList;
 typedef std::vector<UpdateResponseData> UpdateResponseDataList;
 
 }  // namespace syncer
 
 #endif  // SYNC_ENGINE_NON_BLOCKING_SYNC_COMMON_H_