contract: Optimize contract replay after chain reorganization

src/main.cpp

@@ -2226,11 +2226,6 @@ bool CBlock::DisconnectBlock(CTxDB& txdb, CBlockIndex* pindex)
         {
             bDiscTxFailed = true;
         }
-
-        if (pindex->nIsContract == 1)
-        {
-            NN::RevertContracts(vtx[i], pindex);
-        }
     }
 
     // Update block index on disk without changing it in memory.

src/neuralnet/beacon.cpp

@@ -319,6 +319,12 @@ bool BeaconRegistry::ContainsActive(const Cpid& cpid) const
     return ContainsActive(cpid, GetAdjustedTime());
 }
 
+void BeaconRegistry::Reset()
+{
+    m_beacons.clear();
+    m_pending.clear();
+}
+
 void BeaconRegistry::Add(const ContractContext& ctx)
 {
     BeaconPayload payload = ctx->CopyPayloadAs<BeaconPayload>();

src/neuralnet/beacon.h

@@ -465,6 +465,12 @@ class BeaconRegistry : public IContractHandler
     //!
     bool ContainsActive(const Cpid& cpid) const;
 
+    //!
+    //! \brief Destroy the contract handler state to prepare for historical
+    //! contract replay.
+    //!
+    void Reset() override;
+
     //!
     //! \brief Determine whether a beacon contract is valid.
     //!

src/neuralnet/contract/contract.cpp

@@ -144,6 +144,15 @@ class LegacyPayload : public IContractPayload
 //!
 class AppCacheContractHandler : public IContractHandler
 {
+public:
+    void Reset() override
+    {
+        ClearCache(Section::POLL);
+        ClearCache(Section::PROTOCOL);
+        ClearCache(Section::SCRAPER);
+        ClearCache(Section::VOTE);
+    }
+
     bool Validate(const Contract& contract, const CTransaction& tx) const override
     {
         return true; // No contextual validation needed yet
@@ -182,6 +191,12 @@ class AppCacheContractHandler : public IContractHandler
 //!
 class UnknownContractHandler : public IContractHandler
 {
+public:
+    void Reset() override
+    {
+        // Nothing to do.
+    }
+
     bool Validate(const Contract& contract, const CTransaction& tx) const override
     {
         return true; // No contextual validation needed yet
@@ -225,6 +240,17 @@ class UnknownContractHandler : public IContractHandler
 class Dispatcher
 {
 public:
+    //!
+    //! \brief Reset the cached state of each contract handler to prepare for
+    //! historical contract replay.
+    //!
+    void ResetHandlers()
+    {
+        GetBeaconRegistry().Reset();
+        GetWhitelist().Reset();
+        m_appcache_handler.Reset();
+    }
+
     //!
     //! \brief Validate the provided contract and forward it to the appropriate
     //! contract handler.
@@ -343,6 +369,8 @@ void NN::ReplayContracts(const CBlockIndex* pindex)
        return;
     }
 
+    g_dispatcher.ResetHandlers();
+
     CBlock block;
 
     // These are memorized consecutively in order from oldest to newest.

src/neuralnet/contract/handler.h

@@ -77,6 +77,12 @@ struct IContractHandler
     //!
     virtual bool Validate(const Contract& contract, const CTransaction& tx) const = 0;
 
+    //!
+    //! \brief Destroy the contract handler state to prepare for historical
+    //! contract replay.
+    //!
+    virtual void Reset() = 0;
+
     //!
     //! \brief Handle an contract addition.
     //!

src/neuralnet/project.cpp

@@ -154,6 +154,11 @@ WhitelistSnapshot Whitelist::Snapshot() const
     return WhitelistSnapshot(std::atomic_load(&m_projects));
 }
 
+void Whitelist::Reset()
+{
+    std::atomic_store(&m_projects, std::make_shared<ProjectList>());
+}
+
 void Whitelist::Add(const ContractContext& ctx)
 {
     Project project = ctx->CopyPayloadAs<Project>();

src/neuralnet/project.h

@@ -280,6 +280,12 @@ class Whitelist : public IContractHandler
     //!
     WhitelistSnapshot Snapshot() const;
 
+    //!
+    //! \brief Destroy the contract handler state to prepare for historical
+    //! contract replay.
+    //!
+    void Reset() override;
+
     //!
     //! \brief Perform contextual validation for the provided contract.
     //!