[GCM] Add basic collapse key support for upstream

google_apis/gcm/engine/mcs_client.h

Index: google_apis/gcm/engine/mcs_client.h
diff --git a/google_apis/gcm/engine/mcs_client.h b/google_apis/gcm/engine/mcs_client.h
index 1b279508eea604458a02bcfd3c8df0c1f20be0d6..9b55beab3158fdf9551053c7b6ece015eab092b9 100644
--- a/google_apis/gcm/engine/mcs_client.h
+++ b/google_apis/gcm/engine/mcs_client.h
@@ -129,8 +129,10 @@ class GCM_EXPORT MCSClient {
  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;
 
@@ -212,6 +214,9 @@ class GCM_EXPORT MCSClient {
   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.