core,eth: api for flushing block state

core/blockchain.go

@@ -2324,3 +2324,16 @@ func (bc *BlockChain) InsertHeaderChain(chain []*types.Header, checkFreq int) (i
 	_, err := bc.hc.InsertHeaderChain(chain, start, bc.forker)
 	return 0, err
 }
+
+// FlushState persists the post-state of a block to disk.
+func (bc *BlockChain) FlushState(number uint64) error {
+	if !bc.chainmu.TryLock() {
+		return errChainStopped
+	}
+	defer bc.chainmu.Unlock()
+
+	triedb := bc.stateCache.TrieDB()
+	block := bc.GetBlockByNumber(number)
+	log.Info("Writing cached state to disk", "block", block.Number(), "hash", block.Hash(), "root", block.Root())
+	return triedb.Commit(block.Root(), true, nil)
+}

eth/api.go

@@ -607,3 +607,12 @@ func (api *PrivateDebugAPI) GetAccessibleState(from, to rpc.BlockNumber) (uint64
 	}
 	return 0, fmt.Errorf("No state found")
 }
+
+// FlushState persists the state of a given block to disk.
+func (api *PrivateDebugAPI) FlushState(number rpc.BlockNumber) error {
+	// Genesis, latest and pending not supported
+	if number.Int64() <= 0 {
+		return fmt.Errorf("Invalid block number")
+	}
+	return api.eth.BlockChain().FlushState(uint64(number.Int64()))
+}

internal/web3ext/web3ext.go

@@ -471,6 +471,12 @@ web3._extend({
 			params: 2,
 			inputFormatter:[web3._extend.formatters.inputBlockNumberFormatter, web3._extend.formatters.inputBlockNumberFormatter],
 		}),
+		new web3._extend.Method({
+			name: 'flushState',
+			call: 'debug_flushState',
+			params: 1,
+			inputFormatter:[web3._extend.formatters.inputBlockNumberFormatter],
+		}),
 	],
 	properties: []
 });