tree fd98fb64be85341d1d4e5816982611e9802d1635
parent 3544ddde20df26ceb3efc1487a2524ae4316ea0c
author Raja Daoud <rdaoud@google.com> 1442271040 -0700
committer Raja Daoud <rdaoud@google.com> 1442271040 -0700

syncbase/vsync: SyncGroup and DAG changes for SG syncing

* Change SyncGroup storage to support their versioning and being tracked
  in DAG and log records.
* Update the SyncGroup join & publish calls to support the asynchronous
  transition from known-but-pending SyncGroup to caught-up after sync.
* Add a SyncGroup local state info to track the number of local peer
  joiners, and the watchability, remote publishing, and sync pending
  states of the SyncGroup.
* Add the retry loop for the SyncGroup publishing to the remote peer.
* Improve error checking of SyncGroup prefixes passed in the Spec.
* Add a 1st-cut HasKey() store util API to bypass the VOM decode.  This
  will be later further optimized for leveldb to avoid a copy of the
  value from the C buffer to the Go buffer.
* Add DAG support to fully prune all nodes for an object including its
  current head node.
* Remove temporay solution of the responder adding the initiator to the
  SyncGroup joiner list.
* Improve unittest coverage.

Change-Id: I4585e248bd9e15b8b9585ec7b1830f8225686b2a