sync refactor

source/libs/sync/src/syncMain.c

@@ -510,15 +510,17 @@ void syncNodeUpdateTerm(SSyncNode* pSyncNode, SyncTerm term) {
 }
 
 void syncNodeBecomeFollower(SSyncNode* pSyncNode) {
+  // maybe clear leader cache
   if (pSyncNode->state == TAOS_SYNC_STATE_LEADER) {
     pSyncNode->leaderCache = EMPTY_RAFT_ID;
   }
 
+  // state change
   pSyncNode->state = TAOS_SYNC_STATE_FOLLOWER;
   syncNodeStopHeartbeatTimer(pSyncNode);
 
-  int32_t electMS = syncUtilElectRandomMS();
-  syncNodeRestartElectTimer(pSyncNode, electMS);
+  // reset elect timer
+  syncNodeResetElectTimer(pSyncNode);
 }
 
 // TLA+ Spec
@@ -540,19 +542,31 @@ void syncNodeBecomeFollower(SSyncNode* pSyncNode) {
 //     /\ UNCHANGED <<messages, currentTerm, votedFor, candidateVars, logVars>>
 //
 void syncNodeBecomeLeader(SSyncNode* pSyncNode) {
+  // state change
   pSyncNode->state = TAOS_SYNC_STATE_LEADER;
+
+  // set leader cache
   pSyncNode->leaderCache = pSyncNode->myRaftId;
 
   for (int i = 0; i < pSyncNode->pNextIndex->replicaNum; ++i) {
+    // maybe overwrite myself, no harm
+    // just do it!
     pSyncNode->pNextIndex->index[i] = pSyncNode->pLogStore->getLastIndex(pSyncNode->pLogStore) + 1;
   }
 
   for (int i = 0; i < pSyncNode->pMatchIndex->replicaNum; ++i) {
+    // maybe overwrite myself, no harm
+    // just do it!
     pSyncNode->pMatchIndex->index[i] = SYNC_INDEX_INVALID;
   }
 
+  // stop elect timer
   syncNodeStopElectTimer(pSyncNode);
+
+  // start heartbeat timer
   syncNodeStartHeartbeatTimer(pSyncNode);
+
+  // start replicate right now!
   syncNodeReplicate(pSyncNode);
 }
 
@@ -578,6 +592,9 @@ void syncNodeCandidate2Follower(SSyncNode* pSyncNode) {
 }
 
 // raft vote --------------
+
+// just called by syncNodeVoteForSelf
+// need assert
 void syncNodeVoteForTerm(SSyncNode* pSyncNode, SyncTerm term, SRaftId* pRaftId) {
   assert(term == pSyncNode->pRaftStore->currentTerm);
   assert(!raftStoreHasVoted(pSyncNode->pRaftStore));
@@ -585,6 +602,7 @@ void syncNodeVoteForTerm(SSyncNode* pSyncNode, SyncTerm term, SRaftId* pRaftId)
   raftStoreVote(pSyncNode->pRaftStore, pRaftId);
 }
 
+// simulate get vote from outside
 void syncNodeVoteForSelf(SSyncNode* pSyncNode) {
   syncNodeVoteForTerm(pSyncNode, pSyncNode->pRaftStore->currentTerm, &(pSyncNode->myRaftId));
 

source/libs/sync/src/syncRaftStore.c

@@ -216,7 +216,7 @@ cJSON *raftStore2Json(SRaftStore *pRaftStore) {
 
 char *raftStore2Str(SRaftStore *pRaftStore) {
   cJSON *pJson = raftStore2Json(pRaftStore);
-  char  *serialized = cJSON_Print(pJson);
+  char * serialized = cJSON_Print(pJson);
   cJSON_Delete(pJson);
   return serialized;
 }

source/libs/sync/src/syncRequestVoteReply.c

@@ -45,6 +45,7 @@ int32_t syncNodeOnRequestVoteReplyCb(SSyncNode* ths, SyncRequestVoteReply* pMsg)
     return ret;
   }
 
+  assert(!(pMsg->term > ths->pRaftStore->currentTerm));
   // no need this code, because if I receive reply.term, then I must have sent for that term.
   //  if (pMsg->term > ths->pRaftStore->currentTerm) {
   //    syncNodeUpdateTerm(ths, pMsg->term);
@@ -52,17 +53,29 @@ int32_t syncNodeOnRequestVoteReplyCb(SSyncNode* ths, SyncRequestVoteReply* pMsg)
 
   assert(pMsg->term == ths->pRaftStore->currentTerm);
 
+  // This tallies votes even when the current state is not Candidate,
+  // but they won't be looked at, so it doesn't matter.
   if (ths->state == TAOS_SYNC_STATE_CANDIDATE) {
     votesRespondAdd(ths->pVotesRespond, pMsg);
     if (pMsg->voteGranted) {
+      // add vote
       voteGrantedVote(ths->pVotesGranted, pMsg);
+
+      // maybe to leader
       if (voteGrantedMajority(ths->pVotesGranted)) {
         if (!ths->pVotesGranted->toLeader) {
           syncNodeCandidate2Leader(ths);
+
+          // prevent to leader again!
           ths->pVotesGranted->toLeader = true;
         }
       }
+    } else {
+      ;
+      // do nothing
+      // UNCHANGED <<votesGranted, voterLog>>
     }
   }
+
   return ret;
 }