Add LwwRegister CRDT

blimp/common/proto/helium.proto

 // Copyright 2016 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.
 //
 // Over-the-wire message definitions used for the Helium synchronization
 // protocol.
 
 syntax = "proto3";
 
 option optimize_for = LITE_RUNTIME;
 
 package blimp.proto;
 
 // Vector clock that is used to get the partial order of changes.
 // This class is the proto definition of
 // //blimp/net/helium/vector_clock.h
 message VectorClockMessage {
   uint64 local_revision = 1;
   uint64 remote_revision = 2;
 }
 
 // Sample proto for test purposes.
 message TestChangesetMessage {
   int32 value1 = 1;
   int32 value2 = 2;
 }
 
+message LwwRegisterChangesetMessage {
+  oneof register {
+    int32 integer_value = 1;

[scf, 2016/10/10 19:45:46]

rename to something that convey the size: |i32_value|

[steimel, 2016/10/11 16:39:16]

Gotcha. If we end up keeping with protos instead of moving to CodedInputStreams,
I'll update the name

+    string string_value = 2;
+  }
+}
+
 // A union of serializable Changeset types. There will be one for each Helium
 // Object that requires serialization.
 message ChangesetMessage {
   oneof payload {
     // Sample message for the test
     TestChangesetMessage test = 1;
+    LwwRegisterChangesetMessage lww_register = 2;
   };
 }
 
 // Message that encapsulates a change for a helium object. It contains
 // information required to restore the object from the time specified in |from|
 // until |to|.
 //
 // This is the main object that will be sent in the Helium transport
 message HeliumMessage {
   // Identifies the local revision that this changeset applies to (relative
   // to the sender), and the remote revision that the local side most recently
   // received (i.e. an ACK, in effect).
   VectorClockMessage from = 1;
 
   // Provides the local view of the vector-clock following application of
   // the changeset. This allows a single changeset to collate changes across
   // several revisions, following a break in connectivity, rather than simply
   // re-transmitting the lost changesets.
   VectorClockMessage to = 2;
 
   // Identifies the Object to which this changeset applies.
   uint32 object_id = 3;
 
   // The changeset that contain the actual changes.
   ChangesetMessage change = 4;
 }