Beispiel #1
0
// ConditionalPut sets the value for a specified key only if
// the expected value matches. If not, the return value contains
// the actual value.
func (r *Range) ConditionalPut(args *proto.ConditionalPutRequest, reply *proto.ConditionalPutResponse) {
	// Handle check for non-existence of key.
	val, err := r.engine.Get(args.Key)
	if err != nil {
		reply.SetGoError(err)
		return
	}
	if args.ExpValue.Bytes == nil && val != nil {
		reply.SetGoError(util.Errorf("key %q already exists", args.Key))
		return
	} else if args.ExpValue.Bytes != nil {
		// Handle check for existence when there is no key.
		if val == nil {
			reply.SetGoError(util.Errorf("key %q does not exist", args.Key))
			return
		} else if !bytes.Equal(args.ExpValue.Bytes, val) {
			// TODO(Jiang-Ming): provide the correct timestamp once switch to use MVCC
			reply.ActualValue = &proto.Value{Bytes: val}
			reply.SetGoError(util.Errorf("key %q does not match existing", args.Key))
			return
		}
	}

	reply.SetGoError(r.internalPut(args.Key, args.Value))
}
Beispiel #2
0
// ConditionalPut sets the value for a specified key only if
// the expected value matches. If not, the return value contains
// the actual value.
func (r *Range) ConditionalPut(args *proto.ConditionalPutRequest, reply *proto.ConditionalPutResponse) {
	val, err := r.mvcc.ConditionalPut(args.Key, args.Timestamp, args.Value, args.ExpValue, args.Txn)
	if err == nil {
		r.updateGossipConfigs(args.Key)
	}
	reply.ActualValue = val
	reply.SetGoError(err)
}