// aborts transactionsuppressing any errors, and frees
func (e *env) CloseTransaction(t *mdb.Txn) error {
t.Abort() // ignore error
e.l.Lock()
defer e.l.Unlock()
e.numOpen--
if e.shouldClose && e.numOpen == 0 && !e.closed {
e.e.Close()
e.closed = true
}
e.e.Close()
return nil
}
// remove
// arg0: dbName
// arg1: key
// returns nil
func remove(args [][]byte, txn *mdb.Txn) ([]byte, error) {
dbName := string(args[0])
dbi, err := txn.DBIOpen(&dbName, mdb.CREATE) // create if not exists
if err != nil {
txn.Abort()
return nil, err
}
err = txn.Del(dbi, args[1], nil)
if err != nil {
txn.Abort()
return nil, err
}
return nil, txn.Commit()
}
// put
// arg0: dbName
// arg1: key
// arg2: value
// returns nil
func put(args [][]byte, txn *mdb.Txn) ([]byte, error) {
if len(args) < 3 {
return nil, fmt.Errorf("Put needs 3 arguments! Got %d args", len(args))
}
dbName := string(args[0])
dbi, err := txn.DBIOpen(&dbName, mdb.CREATE) // create if not exists
if err != nil {
txn.Abort()
return nil, err
}
err = txn.Put(dbi, args[1], args[2], 0)
if err != nil {
txn.Abort()
return nil, err
}
err = txn.Commit()
return nil, err
}
// remove if set to expected val
// arg0: dbName
// arg1: key
// arg2: expectedVal
// ret: [1] if removed, [0] otherwise
func compareAndRemove(args [][]byte, txn *mdb.Txn) ([]byte, error) {
dbName := string(args[0])
dbi, err := txn.DBIOpen(&dbName, mdb.CREATE) // create if not exists
existingVal, err := txn.Get(dbi, args[1])
if err != nil && err != mdb.NotFound {
txn.Abort()
return nil, err
}
if err == mdb.NotFound || bytesEqual(args[2], existingVal) {
err = txn.Del(dbi, args[1], nil)
if err != nil {
return nil, err
}
err = txn.Commit()
return args[3], err
} else {
txn.Abort()
return existingVal, nil
}
}
// transactional get for testing get commands over the wire
// arg0: dbName
// arg1: key
func get(args [][]byte, txn *mdb.Txn) ([]byte, error) {
if len(args) < 2 {
return nil, fmt.Errorf("Get needs 2 arguments! Got %d args", len(args))
}
dbName := string(args[0])
dbi, err := txn.DBIOpen(&dbName, mdb.CREATE) // create if not exists
if err != nil {
txn.Abort()
return nil, err
}
ret, err := txn.Get(dbi, args[1])
if err != nil {
txn.Abort()
return nil, err
}
txn.Abort()
return ret, err
}
// put if not already set
// arg0: dbName
// arg1: key
// arg2: value
// return: [1] if added, [0] otherwise
func putIfAbsent(args [][]byte, txn *mdb.Txn) ([]byte, error) {
dbName := string(args[0])
dbi, err := txn.DBIOpen(&dbName, mdb.CREATE) // create if not exists
if err != nil {
txn.Abort()
return nil, err
}
err = txn.Put(dbi, args[1], args[2], mdb.NOOVERWRITE)
if err == mdb.KeyExist {
txn.Abort()
return []byte{0}, nil
}
if err != nil {
txn.Abort()
return nil, err
}
err = txn.Commit()
return []byte{1}, err
}