ledisdb/ledis/tx.go

204 lines
2.9 KiB
Go

package ledis
import (
"errors"
"github.com/siddontang/ledisdb/store"
"sync"
)
var (
ErrNestTx = errors.New("nest transaction not supported")
ErrTxDone = errors.New("Transaction has already been committed or rolled back")
)
type batch struct {
l *Ledis
store.WriteBatch
sync.Locker
logs [][]byte
tx *Tx
}
type dbBatchLocker struct {
sync.Mutex
dbLock *sync.RWMutex
}
type txBatchLocker struct {
}
func (l *txBatchLocker) Lock() {
}
func (l *txBatchLocker) Unlock() {
}
func (l *dbBatchLocker) Lock() {
l.dbLock.RLock()
l.Mutex.Lock()
}
func (l *dbBatchLocker) Unlock() {
l.Mutex.Unlock()
l.dbLock.RUnlock()
}
func (db *DB) newBatch() *batch {
b := new(batch)
b.WriteBatch = db.bucket.NewWriteBatch()
b.Locker = &dbBatchLocker{dbLock: db.dbLock}
b.l = db.l
return b
}
func (b *batch) Commit() error {
b.l.Lock()
defer b.l.Unlock()
err := b.WriteBatch.Commit()
if b.l.binlog != nil {
if err == nil {
if b.tx == nil {
b.l.binlog.Log(b.logs...)
} else {
b.tx.logs = append(b.tx.logs, b.logs...)
}
}
b.logs = [][]byte{}
}
return err
}
func (b *batch) Lock() {
b.Locker.Lock()
}
func (b *batch) Unlock() {
if b.l.binlog != nil {
b.logs = [][]byte{}
}
b.Rollback()
b.Locker.Unlock()
}
func (b *batch) Put(key []byte, value []byte) {
if b.l.binlog != nil {
buf := encodeBinLogPut(key, value)
b.logs = append(b.logs, buf)
}
b.WriteBatch.Put(key, value)
}
func (b *batch) Delete(key []byte) {
if b.l.binlog != nil {
buf := encodeBinLogDelete(key)
b.logs = append(b.logs, buf)
}
b.WriteBatch.Delete(key)
}
type Tx struct {
*DB
tx *store.Tx
logs [][]byte
}
func (db *DB) IsTransaction() bool {
return db.isTx
}
// Begin a transaction, it will block all other write operations before calling Commit or Rollback.
// You must be very careful to prevent long-time transaction.
func (db *DB) Begin() (*Tx, error) {
if db.isTx {
return nil, ErrNestTx
}
tx := new(Tx)
tx.DB = new(DB)
tx.DB.dbLock = db.dbLock
tx.DB.dbLock.Lock()
tx.DB.l = db.l
tx.DB.sdb = db.sdb
var err error
tx.tx, err = db.sdb.Begin()
if err != nil {
tx.DB.dbLock.Unlock()
return nil, err
}
tx.DB.bucket = tx.tx
tx.DB.isTx = true
tx.DB.index = db.index
tx.DB.kvBatch = tx.newBatch()
tx.DB.listBatch = tx.newBatch()
tx.DB.hashBatch = tx.newBatch()
tx.DB.zsetBatch = tx.newBatch()
tx.DB.binBatch = tx.newBatch()
tx.DB.setBatch = tx.newBatch()
return tx, nil
}
func (tx *Tx) Commit() error {
if tx.tx == nil {
return ErrTxDone
}
tx.l.Lock()
err := tx.tx.Commit()
tx.tx = nil
if len(tx.logs) > 0 {
tx.l.binlog.Log(tx.logs...)
}
tx.l.Unlock()
tx.DB.dbLock.Unlock()
tx.DB = nil
return err
}
func (tx *Tx) Rollback() error {
if tx.tx == nil {
return ErrTxDone
}
err := tx.tx.Rollback()
tx.tx = nil
tx.DB.dbLock.Unlock()
tx.DB = nil
return err
}
func (tx *Tx) newBatch() *batch {
b := new(batch)
b.l = tx.l
b.WriteBatch = tx.tx.NewWriteBatch()
b.Locker = &txBatchLocker{}
b.tx = tx
return b
}