saving resivision id to store

x/evm/keeper/abci.go

@@ -60,5 +60,8 @@ func (k Keeper) EndBlock(ctx sdk.Context, req abci.RequestEndBlock) []abci.Valid
 	bloom := ethtypes.BytesToBloom(k.Bloom.Bytes())
 	k.SetBlockBloom(ctx, req.Height, bloom)
 
+	//set the `next revision id` to store
+	k.CommitStateDB.SetRevisionID()
+
 	return []abci.ValidatorUpdate{}
 }

x/evm/types/key.go

@@ -28,6 +28,7 @@ var (
 	KeyPrefixStorage     = []byte{0x05}
 	KeyPrefixChainConfig = []byte{0x06}
 	KeyPrefixHeightHash  = []byte{0x07}
+	KeyPrefixRevisionID  = []byte{0x08}
 )
 
 // HeightHashKey returns the key for the given chain epoch and height.
@@ -44,6 +45,10 @@ func BloomKey(height int64) []byte {
 	return sdk.Uint64ToBigEndian(uint64(height))
 }
 
+func RevisionKey() []byte {
+	return []byte(ModuleName + "_RevisionID")
+}
+
 // AddressStoragePrefix returns a prefix to iterate over a given account storage.
 func AddressStoragePrefix(address ethcmn.Address) []byte {
 	return append(KeyPrefixStorage, address.Bytes()...)

x/evm/types/statedb.go

@@ -1,6 +1,7 @@
 package types
 
 import (
+	"encoding/binary"
 	"fmt"
 	"math/big"
 	"sort"
@@ -595,7 +596,7 @@ func (csdb *CommitStateDB) deleteStateObject(so *stateObject) {
 
 // Snapshot returns an identifier for the current revision of the state.
 func (csdb *CommitStateDB) Snapshot() int {
-	id := csdb.nextRevisionID
+	id := csdb.nextRevisionID + csdb.GetRevisionID()
 	csdb.nextRevisionID++
 
 	csdb.validRevisions = append(
@@ -609,6 +610,25 @@ func (csdb *CommitStateDB) Snapshot() int {
 	return id
 }
 
+//GetRevisionID return the revision id from store, return value will be zero if revision id not exists in store
+func (csdb *CommitStateDB) GetRevisionID() int {
+	store := prefix.NewStore(csdb.ctx.KVStore(csdb.storeKey), KeyPrefixRevisionID)
+	bz := store.Get(RevisionKey()) //if not exist, that means RevisionId was never used, return 0
+	if len(bz) == 0 {
+		return 0
+	}
+
+	revision := binary.BigEndian.Uint64(bz)
+	return int(revision)
+}
+
+//set newest revision id to store
+func (csdb *CommitStateDB) SetRevisionID() {
+	revisionID := csdb.GetRevisionID() + csdb.nextRevisionID
+	store := prefix.NewStore(csdb.ctx.KVStore(csdb.storeKey), KeyPrefixRevisionID)
+	store.Set(RevisionKey(), sdk.Uint64ToBigEndian(uint64(revisionID)))
+}
+
 // RevertToSnapshot reverts all state changes made since the given revision.
 func (csdb *CommitStateDB) RevertToSnapshot(revID int) {
 	// find the snapshot in the stack of valid snapshots