// 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
}
// 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
}
}