Implement a bag of chips for sync.

sync/syncable/directory.h

 // 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.
 
 #ifndef SYNC_SYNCABLE_DIRECTORY_H_
 #define SYNC_SYNCABLE_DIRECTORY_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 152 matching lines @@
     sync_pb::DataTypeProgressMarker download_progress[MODEL_TYPE_COUNT];
     // true iff we ever reached the end of the changelog.
     ModelTypeSet initial_sync_ended;
     // The store birthday we were given by the server. Contents are opaque to
     // the client.
     std::string store_birthday;
     // The next local ID that has not been used with this cache-GUID.
     int64 next_id;
     // The persisted notification state.
     std::string notification_state;
+    // The serialized bag of chips we were given by the server. Contents are
+    // opaque to the client. This is the serialization of a message of type
+    // ChipBag defined in sync.proto.

[tim (not reviewing), 2012/09/11 17:57:20]

This is free of NULL characters?

[qsr (NOT THE RIGHT qsr), 2012/09/11 18:48:49]

 Added comment.

+    std::string bag_of_chips;
   };
 
   // What the Directory needs on initialization to create itself and its Kernel.
   // Filled by DirectoryBackingStore::Load.
   struct KernelLoadInfo {
     PersistedKernelInfo kernel_info;
     std::string cache_guid;  // Created on first initialization, never changes.
     int64 max_metahandle;    // Computed (using sql MAX aggregate) on init.
     KernelLoadInfo() : max_metahandle(0) {
     }
@@ skipping 70 matching lines @@
   void set_initial_sync_ended_for_type(ModelType type, bool value);
 
   const std::string& name() const { return kernel_->name; }
 
   // (Account) Store birthday is opaque to the client, so we keep it in the
   // format it is in the proto buffer in case we switch to a binary birthday
   // later.
   std::string store_birthday() const;
   void set_store_birthday(const std::string& store_birthday);
 
+  // (Account) Bag of chip is an opaque state used by the server to track the
+  // client.
+  std::string bag_of_chips() const;
+  void set_bag_of_chips(const std::string& bag_of_chips);
+
   std::string GetNotificationState() const;
   void SetNotificationState(const std::string& notification_state);
 
   // Unique to each account / client pair.
   std::string cache_guid() const;
 
   // Returns a pointer to our Nigori node handler.
   NigoriHandler* GetNigoriHandler();
 
   // Returns a pointer to our cryptographer. Does not transfer ownership.
@@ skipping 334 matching lines @@
   NigoriHandler* const nigori_handler_;
   Cryptographer* const cryptographer_;
 
   InvariantCheckLevel invariant_check_level_;
 };
 
 }  // namespace syncable
 }  // namespace syncer
 
 #endif // SYNC_SYNCABLE_DIRECTORY_H_