114 lines
1.8 KiB
Go
114 lines
1.8 KiB
Go
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package nodb
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import (
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"errors"
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"fmt"
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"github.com/lunny/nodb/store"
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)
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var (
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ErrNestTx = errors.New("nest transaction not supported")
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ErrTxDone = errors.New("Transaction has already been committed or rolled back")
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)
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type Tx struct {
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*DB
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tx *store.Tx
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logs [][]byte
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}
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func (db *DB) IsTransaction() bool {
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return db.status == DBInTransaction
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}
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// Begin a transaction, it will block all other write operations before calling Commit or Rollback.
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// You must be very careful to prevent long-time transaction.
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func (db *DB) Begin() (*Tx, error) {
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if db.IsTransaction() {
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return nil, ErrNestTx
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}
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tx := new(Tx)
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tx.DB = new(DB)
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tx.DB.l = db.l
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tx.l.wLock.Lock()
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tx.DB.sdb = db.sdb
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var err error
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tx.tx, err = db.sdb.Begin()
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if err != nil {
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tx.l.wLock.Unlock()
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return nil, err
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}
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tx.DB.bucket = tx.tx
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tx.DB.status = DBInTransaction
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tx.DB.index = db.index
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tx.DB.kvBatch = tx.newBatch()
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tx.DB.listBatch = tx.newBatch()
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tx.DB.hashBatch = tx.newBatch()
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tx.DB.zsetBatch = tx.newBatch()
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tx.DB.binBatch = tx.newBatch()
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tx.DB.setBatch = tx.newBatch()
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return tx, nil
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}
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func (tx *Tx) Commit() error {
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if tx.tx == nil {
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return ErrTxDone
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}
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tx.l.commitLock.Lock()
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err := tx.tx.Commit()
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tx.tx = nil
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if len(tx.logs) > 0 {
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tx.l.binlog.Log(tx.logs...)
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}
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tx.l.commitLock.Unlock()
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tx.l.wLock.Unlock()
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tx.DB.bucket = nil
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return err
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}
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func (tx *Tx) Rollback() error {
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if tx.tx == nil {
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return ErrTxDone
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}
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err := tx.tx.Rollback()
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tx.tx = nil
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tx.l.wLock.Unlock()
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tx.DB.bucket = nil
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return err
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}
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func (tx *Tx) newBatch() *batch {
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return tx.l.newBatch(tx.tx.NewWriteBatch(), &txBatchLocker{}, tx)
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}
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func (tx *Tx) Select(index int) error {
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if index < 0 || index >= int(MaxDBNumber) {
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return fmt.Errorf("invalid db index %d", index)
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}
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tx.DB.index = uint8(index)
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return nil
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}
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