core, ethdb: Removed old memory database and use leveldb in-memory db

Removed the old memory database but kept the method around, which now
returns an instance of LDBDatabase with a in-memory leveldb.

Also exposes new database interfaces such as the Reader, Writer and
ReadWriter. All core database functions now take a ReadWriter instead of
a Database.

core/database_util.go

@@ -20,7 +20,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/json"
-	"fmt"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -56,7 +55,7 @@ var (
 )
 
 // GetCanonicalHash retrieves a hash assigned to a canonical block number.
-func GetCanonicalHash(db ethdb.Database, number uint64) common.Hash {
+func GetCanonicalHash(db ethdb.ReadWriter, number uint64) common.Hash {
 	data, _ := db.Get(append(blockNumPrefix, big.NewInt(int64(number)).Bytes()...))
 	if len(data) == 0 {
 		return common.Hash{}
@@ -69,7 +68,7 @@ func GetCanonicalHash(db ethdb.Database, number uint64) common.Hash {
 // last block hash is only updated upon a full block import, the last header
 // hash is updated already at header import, allowing head tracking for the
 // light synchronization mechanism.
-func GetHeadHeaderHash(db ethdb.Database) common.Hash {
+func GetHeadHeaderHash(db ethdb.ReadWriter) common.Hash {
 	data, _ := db.Get(headHeaderKey)
 	if len(data) == 0 {
 		return common.Hash{}
@@ -78,7 +77,7 @@ func GetHeadHeaderHash(db ethdb.Database) common.Hash {
 }
 
 // GetHeadBlockHash retrieves the hash of the current canonical head block.
-func GetHeadBlockHash(db ethdb.Database) common.Hash {
+func GetHeadBlockHash(db ethdb.ReadWriter) common.Hash {
 	data, _ := db.Get(headBlockKey)
 	if len(data) == 0 {
 		return common.Hash{}
@@ -90,7 +89,7 @@ func GetHeadBlockHash(db ethdb.Database) common.Hash {
 // fast synchronization. The difference between this and GetHeadBlockHash is that
 // whereas the last block hash is only updated upon a full block import, the last
 // fast hash is updated when importing pre-processed blocks.
-func GetHeadFastBlockHash(db ethdb.Database) common.Hash {
+func GetHeadFastBlockHash(db ethdb.ReadWriter) common.Hash {
 	data, _ := db.Get(headFastKey)
 	if len(data) == 0 {
 		return common.Hash{}
@@ -100,14 +99,14 @@ func GetHeadFastBlockHash(db ethdb.Database) common.Hash {
 
 // GetHeaderRLP retrieves a block header in its raw RLP database encoding, or nil
 // if the header's not found.
-func GetHeaderRLP(db ethdb.Database, hash common.Hash) rlp.RawValue {
+func GetHeaderRLP(db ethdb.ReadWriter, hash common.Hash) rlp.RawValue {
 	data, _ := db.Get(append(append(blockPrefix, hash[:]...), headerSuffix...))
 	return data
 }
 
 // GetHeader retrieves the block header corresponding to the hash, nil if none
 // found.
-func GetHeader(db ethdb.Database, hash common.Hash) *types.Header {
+func GetHeader(db ethdb.ReadWriter, hash common.Hash) *types.Header {
 	data := GetHeaderRLP(db, hash)
 	if len(data) == 0 {
 		return nil
@@ -121,14 +120,14 @@ func GetHeader(db ethdb.Database, hash common.Hash) *types.Header {
 }
 
 // GetBodyRLP retrieves the block body (transactions and uncles) in RLP encoding.
-func GetBodyRLP(db ethdb.Database, hash common.Hash) rlp.RawValue {
+func GetBodyRLP(db ethdb.ReadWriter, hash common.Hash) rlp.RawValue {
 	data, _ := db.Get(append(append(blockPrefix, hash[:]...), bodySuffix...))
 	return data
 }
 
 // GetBody retrieves the block body (transactons, uncles) corresponding to the
 // hash, nil if none found.
-func GetBody(db ethdb.Database, hash common.Hash) *types.Body {
+func GetBody(db ethdb.ReadWriter, hash common.Hash) *types.Body {
 	data := GetBodyRLP(db, hash)
 	if len(data) == 0 {
 		return nil
@@ -143,7 +142,7 @@ func GetBody(db ethdb.Database, hash common.Hash) *types.Body {
 
 // GetTd retrieves a block's total difficulty corresponding to the hash, nil if
 // none found.
-func GetTd(db ethdb.Database, hash common.Hash) *big.Int {
+func GetTd(db ethdb.ReadWriter, hash common.Hash) *big.Int {
 	data, _ := db.Get(append(append(blockPrefix, hash.Bytes()...), tdSuffix...))
 	if len(data) == 0 {
 		return nil
@@ -158,7 +157,7 @@ func GetTd(db ethdb.Database, hash common.Hash) *big.Int {
 
 // GetBlock retrieves an entire block corresponding to the hash, assembling it
 // back from the stored header and body.
-func GetBlock(db ethdb.Database, hash common.Hash) *types.Block {
+func GetBlock(db ethdb.ReadWriter, hash common.Hash) *types.Block {
 	// Retrieve the block header and body contents
 	header := GetHeader(db, hash)
 	if header == nil {
@@ -174,7 +173,7 @@ func GetBlock(db ethdb.Database, hash common.Hash) *types.Block {
 
 // GetBlockReceipts retrieves the receipts generated by the transactions included
 // in a block given by its hash.
-func GetBlockReceipts(db ethdb.Database, hash common.Hash) types.Receipts {
+func GetBlockReceipts(db ethdb.ReadWriter, hash common.Hash) types.Receipts {
 	data, _ := db.Get(append(blockReceiptsPrefix, hash[:]...))
 	if len(data) == 0 {
 		return nil
@@ -193,7 +192,7 @@ func GetBlockReceipts(db ethdb.Database, hash common.Hash) types.Receipts {
 
 // GetTransaction retrieves a specific transaction from the database, along with
 // its added positional metadata.
-func GetTransaction(db ethdb.Database, hash common.Hash) (*types.Transaction, common.Hash, uint64, uint64) {
+func GetTransaction(db ethdb.ReadWriter, hash common.Hash) (*types.Transaction, common.Hash, uint64, uint64) {
 	// Retrieve the transaction itself from the database
 	data, _ := db.Get(hash.Bytes())
 	if len(data) == 0 {
@@ -220,7 +219,7 @@ func GetTransaction(db ethdb.Database, hash common.Hash) (*types.Transaction, co
 }
 
 // GetReceipt returns a receipt by hash
-func GetReceipt(db ethdb.Database, txHash common.Hash) *types.Receipt {
+func GetReceipt(db ethdb.ReadWriter, txHash common.Hash) *types.Receipt {
 	data, _ := db.Get(append(receiptsPrefix, txHash[:]...))
 	if len(data) == 0 {
 		return nil
@@ -234,7 +233,7 @@ func GetReceipt(db ethdb.Database, txHash common.Hash) *types.Receipt {
 }
 
 // WriteCanonicalHash stores the canonical hash for the given block number.
-func WriteCanonicalHash(db ethdb.Database, hash common.Hash, number uint64) error {
+func WriteCanonicalHash(db ethdb.ReadWriter, hash common.Hash, number uint64) error {
 	key := append(blockNumPrefix, big.NewInt(int64(number)).Bytes()...)
 	if err := db.Put(key, hash.Bytes()); err != nil {
 		glog.Fatalf("failed to store number to hash mapping into database: %v", err)
@@ -244,7 +243,7 @@ func WriteCanonicalHash(db ethdb.Database, hash common.Hash, number uint64) erro
 }
 
 // WriteHeadHeaderHash stores the head header's hash.
-func WriteHeadHeaderHash(db ethdb.Database, hash common.Hash) error {
+func WriteHeadHeaderHash(db ethdb.ReadWriter, hash common.Hash) error {
 	if err := db.Put(headHeaderKey, hash.Bytes()); err != nil {
 		glog.Fatalf("failed to store last header's hash into database: %v", err)
 		return err
@@ -253,7 +252,7 @@ func WriteHeadHeaderHash(db ethdb.Database, hash common.Hash) error {
 }
 
 // WriteHeadBlockHash stores the head block's hash.
-func WriteHeadBlockHash(db ethdb.Database, hash common.Hash) error {
+func WriteHeadBlockHash(db ethdb.ReadWriter, hash common.Hash) error {
 	if err := db.Put(headBlockKey, hash.Bytes()); err != nil {
 		glog.Fatalf("failed to store last block's hash into database: %v", err)
 		return err
@@ -262,7 +261,7 @@ func WriteHeadBlockHash(db ethdb.Database, hash common.Hash) error {
 }
 
 // WriteHeadFastBlockHash stores the fast head block's hash.
-func WriteHeadFastBlockHash(db ethdb.Database, hash common.Hash) error {
+func WriteHeadFastBlockHash(db ethdb.ReadWriter, hash common.Hash) error {
 	if err := db.Put(headFastKey, hash.Bytes()); err != nil {
 		glog.Fatalf("failed to store last fast block's hash into database: %v", err)
 		return err
@@ -271,7 +270,7 @@ func WriteHeadFastBlockHash(db ethdb.Database, hash common.Hash) error {
 }
 
 // WriteHeader serializes a block header into the database.
-func WriteHeader(db ethdb.Database, header *types.Header) error {
+func WriteHeader(db ethdb.ReadWriter, header *types.Header) error {
 	data, err := rlp.EncodeToBytes(header)
 	if err != nil {
 		return err
@@ -286,7 +285,7 @@ func WriteHeader(db ethdb.Database, header *types.Header) error {
 }
 
 // WriteBody serializes the body of a block into the database.
-func WriteBody(db ethdb.Database, hash common.Hash, body *types.Body) error {
+func WriteBody(db ethdb.ReadWriter, hash common.Hash, body *types.Body) error {
 	data, err := rlp.EncodeToBytes(body)
 	if err != nil {
 		return err
@@ -301,7 +300,7 @@ func WriteBody(db ethdb.Database, hash common.Hash, body *types.Body) error {
 }
 
 // WriteTd serializes the total difficulty of a block into the database.
-func WriteTd(db ethdb.Database, hash common.Hash, td *big.Int) error {
+func WriteTd(db ethdb.ReadWriter, hash common.Hash, td *big.Int) error {
 	data, err := rlp.EncodeToBytes(td)
 	if err != nil {
 		return err
@@ -316,7 +315,7 @@ func WriteTd(db ethdb.Database, hash common.Hash, td *big.Int) error {
 }
 
 // WriteBlock serializes a block into the database, header and body separately.
-func WriteBlock(db ethdb.Database, block *types.Block) error {
+func WriteBlock(db ethdb.ReadWriter, block *types.Block) error {
 	// Store the body first to retain database consistency
 	if err := WriteBody(db, block.Hash(), block.Body()); err != nil {
 		return err
@@ -331,7 +330,7 @@ func WriteBlock(db ethdb.Database, block *types.Block) error {
 // WriteBlockReceipts stores all the transaction receipts belonging to a block
 // as a single receipt slice. This is used during chain reorganisations for
 // rescheduling dropped transactions.
-func WriteBlockReceipts(db ethdb.Database, hash common.Hash, receipts types.Receipts) error {
+func WriteBlockReceipts(db ethdb.ReadWriter, hash common.Hash, receipts types.Receipts) error {
 	// Convert the receipts into their storage form and serialize them
 	storageReceipts := make([]*types.ReceiptForStorage, len(receipts))
 	for i, receipt := range receipts {
@@ -350,6 +349,42 @@ func WriteBlockReceipts(db ethdb.Database, hash common.Hash, receipts types.Rece
 	return nil
 }
 
+// WriteBlockTransactions stores the transactions associated with a specific block
+// into the given database. Beside writing the transaction, the function also
+// stores a metadata entry along with the transaction, detailing the position
+// of this within the blockchain.
+func WriteBlockTransactions(db ethdb.ReadWriter, header types.Header, transactions types.Transactions) error {
+	// Iterate over each transaction and encode it with its metadata
+	for i, tx := range transactions {
+		// Encode and queue up the transaction for storage
+		data, err := rlp.EncodeToBytes(tx)
+		if err != nil {
+			return err
+		}
+		if err := db.Put(tx.Hash().Bytes(), data); err != nil {
+			return err
+		}
+		// Encode and queue up the transaction metadata for storage
+		meta := struct {
+			BlockHash  common.Hash
+			BlockIndex uint64
+			Index      uint64
+		}{
+			BlockHash:  header.Hash(),
+			BlockIndex: header.Number.Uint64(),
+			Index:      uint64(i),
+		}
+		data, err = rlp.EncodeToBytes(meta)
+		if err != nil {
+			return err
+		}
+		if err := db.Put(append(tx.Hash().Bytes(), txMetaSuffix...), data); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // WriteTransactions stores the transactions associated with a specific block
 // into the given database. Beside writing the transaction, the function also
 // stores a metadata entry along with the transaction, detailing the position
@@ -394,8 +429,10 @@ func WriteTransactions(db ethdb.Database, block *types.Block) error {
 }
 
 // WriteReceipts stores a batch of transaction receipts into the database.
-func WriteReceipts(db ethdb.Database, receipts types.Receipts) error {
+func WriteReceipts(db ethdb.ReadWriter, receipts types.Receipts) error {
-	batch := db.NewBatch()
+	// XXX Batch has been commented out because this is now used for transaction stuff as well
+	// if you want to use batches perhaps you should pass a batch, rather than a database?
+	//batch := db.NewBatch()
 
 	// Iterate over all the receipts and queue them for database injection
 	for _, receipt := range receipts {
@@ -404,40 +441,42 @@ func WriteReceipts(db ethdb.Database, receipts types.Receipts) error {
 		if err != nil {
 			return err
 		}
-		if err := batch.Put(append(receiptsPrefix, receipt.TxHash.Bytes()...), data); err != nil {
+		if err := db.Put(append(receiptsPrefix, receipt.TxHash.Bytes()...), data); err != nil {
 			return err
 		}
 	}
+	/*
 		// Write the scheduled data into the database
 		if err := batch.Write(); err != nil {
 			glog.Fatalf("failed to store receipts into database: %v", err)
 			return err
 		}
+	*/
 	return nil
 }
 
 // DeleteCanonicalHash removes the number to hash canonical mapping.
-func DeleteCanonicalHash(db ethdb.Database, number uint64) {
+func DeleteCanonicalHash(db ethdb.ReadWriter, number uint64) {
 	db.Delete(append(blockNumPrefix, big.NewInt(int64(number)).Bytes()...))
 }
 
 // DeleteHeader removes all block header data associated with a hash.
-func DeleteHeader(db ethdb.Database, hash common.Hash) {
+func DeleteHeader(db ethdb.ReadWriter, hash common.Hash) {
 	db.Delete(append(append(blockPrefix, hash.Bytes()...), headerSuffix...))
 }
 
 // DeleteBody removes all block body data associated with a hash.
-func DeleteBody(db ethdb.Database, hash common.Hash) {
+func DeleteBody(db ethdb.ReadWriter, hash common.Hash) {
 	db.Delete(append(append(blockPrefix, hash.Bytes()...), bodySuffix...))
 }
 
 // DeleteTd removes all block total difficulty data associated with a hash.
-func DeleteTd(db ethdb.Database, hash common.Hash) {
+func DeleteTd(db ethdb.ReadWriter, hash common.Hash) {
 	db.Delete(append(append(blockPrefix, hash.Bytes()...), tdSuffix...))
 }
 
 // DeleteBlock removes all block data associated with a hash.
-func DeleteBlock(db ethdb.Database, hash common.Hash) {
+func DeleteBlock(db ethdb.ReadWriter, hash common.Hash) {
 	DeleteBlockReceipts(db, hash)
 	DeleteHeader(db, hash)
 	DeleteBody(db, hash)
@@ -445,18 +484,18 @@ func DeleteBlock(db ethdb.Database, hash common.Hash) {
 }
 
 // DeleteBlockReceipts removes all receipt data associated with a block hash.
-func DeleteBlockReceipts(db ethdb.Database, hash common.Hash) {
+func DeleteBlockReceipts(db ethdb.ReadWriter, hash common.Hash) {
 	db.Delete(append(blockReceiptsPrefix, hash.Bytes()...))
 }
 
 // DeleteTransaction removes all transaction data associated with a hash.
-func DeleteTransaction(db ethdb.Database, hash common.Hash) {
+func DeleteTransaction(db ethdb.ReadWriter, hash common.Hash) {
 	db.Delete(hash.Bytes())
 	db.Delete(append(hash.Bytes(), txMetaSuffix...))
 }
 
 // DeleteReceipt removes all receipt data associated with a transaction hash.
-func DeleteReceipt(db ethdb.Database, hash common.Hash) {
+func DeleteReceipt(db ethdb.ReadWriter, hash common.Hash) {
 	db.Delete(append(receiptsPrefix, hash.Bytes()...))
 }
 
@@ -465,7 +504,7 @@ func DeleteReceipt(db ethdb.Database, hash common.Hash) {
 // or nil if not found. This method is only used by the upgrade mechanism to
 // access the old combined block representation. It will be dropped after the
 // network transitions to eth/63.
-func GetBlockByHashOld(db ethdb.Database, hash common.Hash) *types.Block {
+func GetBlockByHashOld(db ethdb.ReadWriter, hash common.Hash) *types.Block {
 	data, _ := db.Get(append(blockHashPrefix, hash[:]...))
 	if len(data) == 0 {
 		return nil
@@ -491,8 +530,10 @@ func mipmapKey(num, level uint64) []byte {
 
 // WriteMapmapBloom writes each address included in the receipts' logs to the
 // MIP bloom bin.
-func WriteMipmapBloom(db ethdb.Database, number uint64, receipts types.Receipts) error {
+func WriteMipmapBloom(db ethdb.ReadWriter, number uint64, receipts types.Receipts) error {
-	batch := db.NewBatch()
+	// XXX Batch has been commented out because this is now used for transaction stuff as well
+	// if you want to use batches perhaps you should pass a batch, rather than a database?
+	//batch := db.NewBatch()
 	for _, level := range MIPMapLevels {
 		key := mipmapKey(number, level)
 		bloomDat, _ := db.Get(key)
@@ -502,23 +543,25 @@ func WriteMipmapBloom(db ethdb.Database, number uint64, receipts types.Receipts)
 				bloom.Add(log.Address.Big())
 			}
 		}
-		batch.Put(key, bloom.Bytes())
+		db.Put(key, bloom.Bytes())
 	}
+	/*
 		if err := batch.Write(); err != nil {
 			return fmt.Errorf("mipmap write fail for: %d: %v", number, err)
 		}
+	*/
 	return nil
 }
 
 // GetMipmapBloom returns a bloom filter using the number and level as input
 // parameters. For available levels see MIPMapLevels.
-func GetMipmapBloom(db ethdb.Database, number, level uint64) types.Bloom {
+func GetMipmapBloom(db ethdb.ReadWriter, number, level uint64) types.Bloom {
 	bloomDat, _ := db.Get(mipmapKey(number, level))
 	return types.BytesToBloom(bloomDat)
 }
 
 // GetBlockChainVersion reads the version number from db.
-func GetBlockChainVersion(db ethdb.Database) int {
+func GetBlockChainVersion(db ethdb.ReadWriter) int {
 	var vsn uint
 	enc, _ := db.Get([]byte("BlockchainVersion"))
 	rlp.DecodeBytes(enc, &vsn)
@@ -526,13 +569,13 @@ func GetBlockChainVersion(db ethdb.Database) int {
 }
 
 // WriteBlockChainVersion writes vsn as the version number to db.
-func WriteBlockChainVersion(db ethdb.Database, vsn int) {
+func WriteBlockChainVersion(db ethdb.ReadWriter, vsn int) {
 	enc, _ := rlp.EncodeToBytes(uint(vsn))
 	db.Put([]byte("BlockchainVersion"), enc)
 }
 
 // WriteChainConfig writes the chain config settings to the database.
-func WriteChainConfig(db ethdb.Database, hash common.Hash, cfg *ChainConfig) error {
+func WriteChainConfig(db ethdb.ReadWriter, hash common.Hash, cfg *ChainConfig) error {
 	// short circuit and ignore if nil config. GetChainConfig
 	// will return a default.
 	if cfg == nil {
@@ -548,7 +591,7 @@ func WriteChainConfig(db ethdb.Database, hash common.Hash, cfg *ChainConfig) err
 }
 
 // GetChainConfig will fetch the network settings based on the given hash.
-func GetChainConfig(db ethdb.Database, hash common.Hash) (*ChainConfig, error) {
+func GetChainConfig(db ethdb.ReadWriter, hash common.Hash) (*ChainConfig, error) {
 	jsonChainConfig, _ := db.Get(append(configPrefix, hash[:]...))
 	if len(jsonChainConfig) == 0 {
 		return nil, ChainConfigNotFoundErr

ethdb/database.go

@@ -285,6 +285,36 @@ func (db *LDBDatabase) NewBatch() Batch {
 	return &ldbBatch{db: db.db, b: new(leveldb.Batch)}
 }
 
+func (db *LDBDatabase) OpenTransaction() (Transaction, error) {
+	tx, err := db.db.OpenTransaction()
+	if err != nil {
+		return nil, err
+	}
+
+	return &ldbTransaction{db: db.db, tx: tx}, nil
+}
+
+type ldbTransaction struct {
+	db *leveldb.DB
+	tx *leveldb.Transaction
+}
+
+func (t *ldbTransaction) Put(key, value []byte) error {
+	return t.tx.Put(key, value, nil)
+}
+
+func (t *ldbTransaction) Delete(key []byte) error {
+	return t.tx.Delete(key, nil)
+}
+
+func (t *ldbTransaction) Get(key []byte) ([]byte, error) {
+	return t.tx.Get(key, nil)
+}
+
+func (t *ldbTransaction) Commit() error {
+	return t.tx.Commit()
+}
+
 type ldbBatch struct {
 	db *leveldb.DB
 	b  *leveldb.Batch

ethdb/interface.go

@@ -17,14 +17,35 @@
 package ethdb
 
 type Database interface {
-	Put(key []byte, value []byte) error
+	Writer
-	Get(key []byte) ([]byte, error)
+	Reader
-	Delete(key []byte) error
+
 	Close()
 	NewBatch() Batch
+	OpenTransaction() (Transaction, error)
 }
 
 type Batch interface {
 	Put(key, value []byte) error
 	Write() error
 }
+
+type Writer interface {
+	Put(key []byte, value []byte) error
+	Delete(key []byte) error
+}
+
+type Reader interface {
+	Get(key []byte) ([]byte, error)
+}
+
+type ReadWriter interface {
+	Reader
+	Writer
+}
+
+type Transaction interface {
+	ReadWriter
+
+	Commit() error
+}

ethdb/memory_database.go

@@ -17,109 +17,14 @@
 package ethdb
 
 import (
-	"errors"
+	"github.com/syndtr/goleveldb/leveldb"
-	"sync"
+	"github.com/syndtr/goleveldb/leveldb/storage"
-
-	"github.com/ethereum/go-ethereum/common"
 )
 
-/*
+func NewMemDatabase() (*LDBDatabase, error) {
- * This is a test memory database. Do not use for any production it does not get persisted
+	db, err := leveldb.Open(storage.NewMemStorage(), nil)
- */
+	if err != nil {
-type MemDatabase struct {
+		return nil, err
-	db   map[string][]byte
-	lock sync.RWMutex
 	}
-
+	return &LDBDatabase{db: db, fn: "<memory>"}, nil
-func NewMemDatabase() (*MemDatabase, error) {
-	return &MemDatabase{
-		db: make(map[string][]byte),
-	}, nil
-}
-
-func (db *MemDatabase) Put(key []byte, value []byte) error {
-	db.lock.Lock()
-	defer db.lock.Unlock()
-
-	db.db[string(key)] = common.CopyBytes(value)
-	return nil
-}
-
-func (db *MemDatabase) Set(key []byte, value []byte) {
-	db.lock.Lock()
-	defer db.lock.Unlock()
-
-	db.Put(key, value)
-}
-
-func (db *MemDatabase) Get(key []byte) ([]byte, error) {
-	db.lock.RLock()
-	defer db.lock.RUnlock()
-
-	if entry, ok := db.db[string(key)]; ok {
-		return entry, nil
-	}
-	return nil, errors.New("not found")
-}
-
-func (db *MemDatabase) Keys() [][]byte {
-	db.lock.RLock()
-	defer db.lock.RUnlock()
-
-	keys := [][]byte{}
-	for key, _ := range db.db {
-		keys = append(keys, []byte(key))
-	}
-	return keys
-}
-
-/*
-func (db *MemDatabase) GetKeys() []*common.Key {
-	data, _ := db.Get([]byte("KeyRing"))
-
-	return []*common.Key{common.NewKeyFromBytes(data)}
-}
-*/
-
-func (db *MemDatabase) Delete(key []byte) error {
-	db.lock.Lock()
-	defer db.lock.Unlock()
-
-	delete(db.db, string(key))
-	return nil
-}
-
-func (db *MemDatabase) Close() {}
-
-func (db *MemDatabase) NewBatch() Batch {
-	return &memBatch{db: db}
-}
-
-type kv struct{ k, v []byte }
-
-type memBatch struct {
-	db     *MemDatabase
-	writes []kv
-	lock   sync.RWMutex
-}
-
-func (b *memBatch) Put(key, value []byte) error {
-	b.lock.Lock()
-	defer b.lock.Unlock()
-
-	b.writes = append(b.writes, kv{common.CopyBytes(key), common.CopyBytes(value)})
-	return nil
-}
-
-func (b *memBatch) Write() error {
-	b.lock.RLock()
-	defer b.lock.RUnlock()
-
-	b.db.lock.Lock()
-	defer b.db.lock.Unlock()
-
-	for _, kv := range b.writes {
-		b.db.db[string(kv.k)] = kv.v
-	}
-	return nil
 }