[GCM] Add basic collapse key support for upstream

google_apis/gcm/engine/mcs_client.h

 // Copyright 2013 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 GOOGLE_APIS_GCM_ENGINE_MCS_CLIENT_H_
 #define GOOGLE_APIS_GCM_ENGINE_MCS_CLIENT_H_
 
 #include <deque>
 #include <map>
 #include <string>
@@ skipping 111 matching lines @@
   // WARNING: This is permanent, and the client must be recreated with new
   // credentials afterwards.
   void Destroy();
 
   // Returns the current state of the client.
   State state() const { return state_; }
 
  private:
   typedef uint32 StreamId;
   typedef std::string PersistentId;
+  typedef std::string AppId;

[fgorski, 2014/01/28 18:10:27]

If you mean to use project_id as a value of that field, calling it app_id might
be problematic.
* First we already use that name higher up the stack. (later in the code you are
getting the value of from (meaning project_id) and assign it to variable name
app_id)
* Second, there might be multiple apps using the same project ID to access
information.

Perhaps a combination of project_id/app_id (package name) works better?

[fgorski, 2014/01/28 18:13:31]

And speaking of multi-profile scenario... what if multiple profiles have the
same app running?

[Nicolas Zea, 2014/01/31 11:58:43]

I've gone ahead and modified this to use a CollapseKey class that cleans this up
(and supports multi-profile better, good catch on that).

   typedef std::vector<StreamId> StreamIdList;
   typedef std::vector<PersistentId> PersistentIdList;
+  typedef std::map<std::string, ReliablePacketInfo*> TokenMap;
   typedef std::map<StreamId, PersistentId> StreamIdToPersistentIdMap;
   typedef linked_ptr<ReliablePacketInfo> MCSPacketInternal;
 
   // Resets the internal state and builds a new login request, acknowledging
   // any pending server-to-device messages and rebuilding the send queue
   // from all unacknowledged device-to-server messages.
   // Should only be called when the connection has been reset.
   void ResetStateAndBuildLoginRequest(mcs_proto::LoginRequest* request);
 
   // Send a heartbeat to the MCS server.
@@ skipping 61 matching lines @@
   ConnectionHandler* connection_handler_;
 
   // -----  Reliablie Message Queue section -----
   // Note: all queues/maps are ordered from oldest (front/begin) message to
   // most recent (back/end).
 
   // Send/acknowledge queues.
   std::deque<MCSPacketInternal> to_send_;
   std::deque<MCSPacketInternal> to_resend_;
 
+  // Map of collapse keys to their pending messages.
+  std::map<AppId, linked_ptr<TokenMap> > collapse_key_map_;
+
   // Last device_to_server stream id acknowledged by the server.
   StreamId last_device_to_server_stream_id_received_;
   // Last server_to_device stream id acknowledged by this device.
   StreamId last_server_to_device_stream_id_received_;
   // The stream id for the last sent message. A new message should consume
   // stream_id_out_ + 1.
   StreamId stream_id_out_;
   // The stream id of the last received message. The LoginResponse will always
   // have a stream id of 1, and stream ids increment by 1 for each received
   // message.
@@ skipping 21 matching lines @@
   HeartbeatManager heartbeat_manager_;
 
   base::WeakPtrFactory<MCSClient> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MCSClient);
 };
 
 } // namespace gcm
 
 #endif  // GOOGLE_APIS_GCM_ENGINE_MCS_CLIENT_H_