From ba26e58774f11d1ca8ef234af461f601f75d4c0a Mon Sep 17 00:00:00 2001
From: matt dannenberg <matt.dannenberg@10gen.com>
Date: Mon, 4 Aug 2014 11:55:04 -0400
Subject: SERVER-14453 Implement processReplSetGetRBID in
 ReplicationCoordinatorImpl

---
 src/mongo/db/repl/repl_coordinator_impl.cpp      | 12 ++++++++++--
 src/mongo/db/repl/repl_coordinator_impl.h        |  4 ++++
 src/mongo/db/repl/repl_coordinator_impl_test.cpp | 13 +++++++++++++
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/mongo/db/repl/repl_coordinator_impl.cpp b/src/mongo/db/repl/repl_coordinator_impl.cpp
index ffb5a7ac45a..a284066aed7 100644
--- a/src/mongo/db/repl/repl_coordinator_impl.cpp
+++ b/src/mongo/db/repl/repl_coordinator_impl.cpp
@@ -103,6 +103,10 @@ namespace repl {
             return;
         }
 
+        // this is ok but micros or combo with some rand() and/or 64 bits might be better --
+        // imagine a restart and a clock correction simultaneously (very unlikely but possible...)
+        _rbid = static_cast<int>(curTimeMillis64());
+
         _topCoord->registerStateChangeCallback(
                 stdx::bind(&ReplicationCoordinatorImpl::_onSelfStateChange,
                            this,
@@ -708,11 +712,15 @@ namespace repl {
     }
 
     Status ReplicationCoordinatorImpl::processReplSetGetRBID(BSONObjBuilder* resultObj) {
-        // TODO
+        boost::lock_guard<boost::mutex> lk(_mutex);
+        resultObj->append("rbid", _rbid);
         return Status::OK();
     }
 
-    void ReplicationCoordinatorImpl::incrementRollbackID() { /* TODO */ }
+    void ReplicationCoordinatorImpl::incrementRollbackID() {
+        boost::lock_guard<boost::mutex> lk(_mutex);
+        ++_rbid;
+    }
 
     Status ReplicationCoordinatorImpl::processReplSetFresh(const ReplSetFreshArgs& args,
                                                            BSONObjBuilder* resultObj) {
diff --git a/src/mongo/db/repl/repl_coordinator_impl.h b/src/mongo/db/repl/repl_coordinator_impl.h
index 0a7b4465cb7..b93c5f4f21a 100644
--- a/src/mongo/db/repl/repl_coordinator_impl.h
+++ b/src/mongo/db/repl/repl_coordinator_impl.h
@@ -314,6 +314,10 @@ namespace repl {
 
         /// ============= All members below this line are guarded by _mutex ==================== ///
 
+        // Rollback ID. Used to check if a rollback happened during some interval of time
+        // TODO: ideally this should only change on rollbacks NOT on mongod restarts also.
+        int _rbid;
+
         // list of information about clients waiting on replication.  Does *not* own the
         // WaiterInfos.
         std::vector<WaiterInfo*> _replicationWaiterList;
diff --git a/src/mongo/db/repl/repl_coordinator_impl_test.cpp b/src/mongo/db/repl/repl_coordinator_impl_test.cpp
index d4fb42f277f..924ae02029f 100644
--- a/src/mongo/db/repl/repl_coordinator_impl_test.cpp
+++ b/src/mongo/db/repl/repl_coordinator_impl_test.cpp
@@ -251,6 +251,19 @@ namespace {
         ASSERT_OK(statusAndDur.status);
     }
 
+    TEST_F(ReplCoordTest, BasicRBIDUsage) {
+        start();
+        BSONObjBuilder result;
+        getReplCoord()->processReplSetGetRBID(&result);
+        long long initialValue = result.obj()["rbid"].Int();
+        getReplCoord()->incrementRollbackID();
+
+        BSONObjBuilder result2;
+        getReplCoord()->processReplSetGetRBID(&result2);
+        long long incrementedValue = result2.obj()["rbid"].Int();
+        ASSERT_EQUALS(incrementedValue, initialValue + 1);
+    }
+
     TEST_F(ReplCoordTest, AwaitReplicationNumberOfNodesNonBlocking) {
         assertStartSuccess(
                 BSON("_id" << "mySet" <<
-- 
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