Keep the most recent gobject votes only (#2815)

* Keep the most recent gobject vote only

We don't need to store full vote data for old votes - we never relay them to other nodes anyway.
Still keep old hashes to avoid re-requesting data etc.

* add comment

* Drop getvotes rpc

* Compare vote signals, do not compare hashes

Also add comments

src/governance-votedb.cpp

@@ -28,6 +28,7 @@ void CGovernanceObjectVoteFile::AddVote(const CGovernanceVote& vote)
     listVotes.push_front(vote);
     mapVoteIndex.emplace(nHash, listVotes.begin());
     ++nMemoryVotes;
+    RemoveOldVotes(vote);
 }
 
 bool CGovernanceObjectVoteFile::HasVote(const uint256& nHash) const
@@ -90,6 +91,24 @@ std::set<uint256> CGovernanceObjectVoteFile::RemoveInvalidVotes(const COutPoint&
     return removedVotes;
 }
 
+void CGovernanceObjectVoteFile::RemoveOldVotes(const CGovernanceVote& vote)
+{
+    vote_l_it it = listVotes.begin();
+    while (it != listVotes.end()) {
+        if (it->GetMasternodeOutpoint() == vote.GetMasternodeOutpoint() // same masternode
+            && it->GetParentHash() == vote.GetParentHash() // same governance object (e.g. same proposal)
+            && it->GetSignal() == vote.GetSignal() // same signal (e.g. "funding", "delete", etc.)
+            && it->GetTimestamp() < vote.GetTimestamp()) // older than new vote
+        {
+            --nMemoryVotes;
+            mapVoteIndex.erase(it->GetHash());
+            listVotes.erase(it++);
+        } else {
+            ++it;
+        }
+    }
+}
+
 void CGovernanceObjectVoteFile::RebuildIndex()
 {
     mapVoteIndex.clear();

src/governance-votedb.h

@@ -88,6 +88,9 @@ class CGovernanceObjectVoteFile
     }
 
 private:
+    // Drop older votes for the same gobject from the same masternode
+    void RemoveOldVotes(const CGovernanceVote& vote);
+
     void RebuildIndex();
 };
 

src/governance.cpp

@@ -478,19 +478,6 @@ CGovernanceObject* CGovernanceManager::FindGovernanceObject(const uint256& nHash
     return nullptr;
 }
 
-std::vector<CGovernanceVote> CGovernanceManager::GetMatchingVotes(const uint256& nParentHash) const
-{
-    LOCK(cs);
-    std::vector<CGovernanceVote> vecResult;
-
-    object_m_cit it = mapObjects.find(nParentHash);
-    if (it == mapObjects.end()) {
-        return vecResult;
-    }
-
-    return it->second.GetVoteFile().GetVotes();
-}
-
 std::vector<CGovernanceVote> CGovernanceManager::GetCurrentVotes(const uint256& nParentHash, const COutPoint& mnCollateralOutpointFilter) const
 {
     LOCK(cs);

src/governance.h

@@ -309,7 +309,6 @@ class CGovernanceManager
     CGovernanceObject* FindGovernanceObject(const uint256& nHash);
 
     // These commands are only used in RPC
-    std::vector<CGovernanceVote> GetMatchingVotes(const uint256& nParentHash) const;
     std::vector<CGovernanceVote> GetCurrentVotes(const uint256& nParentHash, const COutPoint& mnCollateralOutpointFilter) const;
     std::vector<const CGovernanceObject*> GetAllNewerThan(int64_t nMoreThanTime) const;
 

src/rpc/governance.cpp

@@ -812,49 +812,6 @@ UniValue gobject_get(const JSONRPCRequest& request)
     return objResult;
 }
 
-void gobject_getvotes_help()
-{
-    throw std::runtime_error(
-                "gobject getvotes <governance-hash>\n"
-                "Get all votes for a governance object hash (including old votes)\n"
-                "\nArguments:\n"
-                "1. governance-hash   (string, required) object id\n"
-                );
-}
-
-UniValue gobject_getvotes(const JSONRPCRequest& request)
-{
-    if (request.fHelp || request.params.size() != 2)
-        gobject_getvotes_help();
-
-    // COLLECT PARAMETERS FROM USER
-
-    uint256 hash = ParseHashV(request.params[1], "Governance hash");
-
-    // FIND OBJECT USER IS LOOKING FOR
-
-    LOCK(governance.cs);
-
-    CGovernanceObject* pGovObj = governance.FindGovernanceObject(hash);
-
-    if (pGovObj == nullptr) {
-        throw JSONRPCError(RPC_INVALID_PARAMETER, "Unknown governance-hash");
-    }
-
-    // REPORT RESULTS TO USER
-
-    UniValue bResult(UniValue::VOBJ);
-
-    // GET MATCHING VOTES BY HASH, THEN SHOW USERS VOTE INFORMATION
-
-    std::vector<CGovernanceVote> vecVotes = governance.GetMatchingVotes(hash);
-    for (const auto& vote : vecVotes) {
-        bResult.push_back(Pair(vote.GetHash().ToString(),  vote.ToString()));
-    }
-
-    return bResult;
-}
-
 void gobject_getcurrentvotes_help()
 {
     throw std::runtime_error(
@@ -921,7 +878,6 @@ UniValue gobject_getcurrentvotes(const JSONRPCRequest& request)
             "  deserialize        - Deserialize governance object from hex string to JSON\n"
             "  count              - Count governance objects and votes (additional param: 'json' or 'all', default: 'json')\n"
             "  get                - Get governance object by hash\n"
-            "  getvotes           - Get all votes for a governance object hash (including old votes)\n"
             "  getcurrentvotes    - Get only current (tallying) votes for a governance object hash (does not include old votes)\n"
             "  list               - List governance objects (can be filtered by signal and/or object type)\n"
             "  diff               - List differences since last diff\n"
@@ -978,11 +934,8 @@ UniValue gobject(const JSONRPCRequest& request)
     } else if (strCommand == "get") {
         // GET SPECIFIC GOVERNANCE ENTRY
         return gobject_get(request);
-    } else if (strCommand == "getvotes") {
-        // GETVOTES FOR SPECIFIC GOVERNANCE OBJECT
-        return gobject_getvotes(request);
     } else if (strCommand == "getcurrentvotes") {
-        // GETVOTES FOR SPECIFIC GOVERNANCE OBJECT
+        // GET VOTES FOR SPECIFIC GOVERNANCE OBJECT
         return gobject_getcurrentvotes(request);
     } else {
         gobject_help();