core/rawdb: separate raw database access to own package (#16666)

core/rawdb/accessors_metadata.go

@@ -0,0 +1,90 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rawdb
+
+import (
+	"encoding/json"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/params"
+	"github.com/ethereum/go-ethereum/rlp"
+)
+
+// ReadDatabaseVersion retrieves the version number of the database.
+func ReadDatabaseVersion(db DatabaseReader) int {
+	var version int
+
+	enc, _ := db.Get(databaseVerisionKey)
+	rlp.DecodeBytes(enc, &version)
+
+	return version
+}
+
+// WriteDatabaseVersion stores the version number of the database
+func WriteDatabaseVersion(db DatabaseWriter, version int) {
+	enc, _ := rlp.EncodeToBytes(version)
+	if err := db.Put(databaseVerisionKey, enc); err != nil {
+		log.Crit("Failed to store the database version", "err", err)
+	}
+}
+
+// ReadChainConfig retrieves the consensus settings based on the given genesis hash.
+func ReadChainConfig(db DatabaseReader, hash common.Hash) *params.ChainConfig {
+	data, _ := db.Get(append(configPrefix, hash[:]...))
+	if len(data) == 0 {
+		return nil
+	}
+	var config params.ChainConfig
+	if err := json.Unmarshal(data, &config); err != nil {
+		log.Error("Invalid chain config JSON", "hash", hash, "err", err)
+		return nil
+	}
+	return &config
+}
+
+// WriteChainConfig writes the chain config settings to the database.
+func WriteChainConfig(db DatabaseWriter, hash common.Hash, cfg *params.ChainConfig) {
+	if cfg == nil {
+		return
+	}
+	data, err := json.Marshal(cfg)
+	if err != nil {
+		log.Crit("Failed to JSON encode chain config", "err", err)
+	}
+	if err := db.Put(append(configPrefix, hash[:]...), data); err != nil {
+		log.Crit("Failed to store chain config", "err", err)
+	}
+}
+
+// ReadPreimage retrieves a single preimage of the provided hash.
+func ReadPreimage(db DatabaseReader, hash common.Hash) []byte {
+	data, _ := db.Get(append(preimagePrefix, hash.Bytes()...))
+	return data
+}
+
+// WritePreimages writes the provided set of preimages to the database. `number` is the
+// current block number, and is used for debug messages only.
+func WritePreimages(db DatabaseWriter, number uint64, preimages map[common.Hash][]byte) {
+	for hash, preimage := range preimages {
+		if err := db.Put(append(preimagePrefix, hash.Bytes()...), preimage); err != nil {
+			log.Crit("Failed to store trie preimage", "err", err)
+		}
+	}
+	preimageCounter.Inc(int64(len(preimages)))
+	preimageHitCounter.Inc(int64(len(preimages)))
+}