// SignRawTransaction2Async returns an instance of a type that can be used to
// get the result of the RPC at some future time by invoking the Receive
// function on the returned instance.
//
// See SignRawTransaction2 for the blocking version and more details.
func (c *Client) SignRawTransaction2Async(tx *wire.MsgTx, inputs []dcrjson.RawTxInput) FutureSignRawTransactionResult {
txHex := ""
if tx != nil {
// Serialize the transaction and convert to hex string.
buf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))
if err := tx.Serialize(buf); err != nil {
return newFutureError(err)
}
txHex = hex.EncodeToString(buf.Bytes())
}
cmd := dcrjson.NewSignRawTransactionCmd(txHex, &inputs, nil, nil)
return c.sendCmd(cmd)
}
// calcPriority returns a transaction priority given a transaction and the sum
// of each of its input values multiplied by their age (# of confirmations).
// Thus, the final formula for the priority is:
// sum(inputValue * inputAge) / adjustedTxSize
func calcPriority(tx *wire.MsgTx, utxoView *blockchain.UtxoViewpoint, nextBlockHeight int64) float64 {
// In order to encourage spending multiple old unspent transaction
// outputs thereby reducing the total set, don't count the constant
// overhead for each input as well as enough bytes of the signature
// script to cover a pay-to-script-hash redemption with a compressed
// pubkey. This makes additional inputs free by boosting the priority
// of the transaction accordingly. No more incentive is given to avoid
// encouraging gaming future transactions through the use of junk
// outputs. This is the same logic used in the reference
// implementation.
//
// The constant overhead for a txin is 41 bytes since the previous
// outpoint is 36 bytes + 4 bytes for the sequence + 1 byte the
// signature script length.
//
// A compressed pubkey pay-to-script-hash redemption with a maximum len
// signature is of the form:
// [OP_DATA_73 <73-byte sig> + OP_DATA_35 + {OP_DATA_33
// <33 byte compresed pubkey> + OP_CHECKSIG}]
//
// Thus 1 + 73 + 1 + 1 + 33 + 1 = 110
overhead := 0
for _, txIn := range tx.TxIn {
// Max inputs + size can't possibly overflow here.
overhead += 41 + minInt(110, len(txIn.SignatureScript))
}
serializedTxSize := tx.SerializeSize()
if overhead >= serializedTxSize {
return 0.0
}
inputValueAge := calcInputValueAge(tx, utxoView, nextBlockHeight)
return inputValueAge / float64(serializedTxSize-overhead)
}
// SendRawTransactionAsync returns an instance of a type that can be used to get
// the result of the RPC at some future time by invoking the Receive function on
// the returned instance.
//
// See SendRawTransaction for the blocking version and more details.
func (c *Client) SendRawTransactionAsync(tx *wire.MsgTx, allowHighFees bool) FutureSendRawTransactionResult {
txHex := ""
if tx != nil {
// Serialize the transaction and convert to hex string.
buf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))
if err := tx.Serialize(buf); err != nil {
return newFutureError(err)
}
txHex = hex.EncodeToString(buf.Bytes())
}
cmd := dcrjson.NewSendRawTransactionCmd(txHex, &allowHighFees)
return c.sendCmd(cmd)
}
// BUGS:
// - InputIndexes request field is ignored.
func (s *walletServer) SignTransaction(ctx context.Context, req *pb.SignTransactionRequest) (
*pb.SignTransactionResponse, error) {
defer zero.Bytes(req.Passphrase)
var tx wire.MsgTx
err := tx.Deserialize(bytes.NewReader(req.SerializedTransaction))
if err != nil {
return nil, grpc.Errorf(codes.InvalidArgument,
"Bytes do not represent a valid raw transaction: %v", err)
}
lock := make(chan time.Time, 1)
defer func() {
lock <- time.Time{} // send matters, not the value
}()
err = s.wallet.Unlock(req.Passphrase, lock)
if err != nil {
return nil, translateError(err)
}
invalidSigs, err := s.wallet.SignTransaction(&tx, txscript.SigHashAll, nil, nil, nil)
if err != nil {
return nil, translateError(err)
}
invalidInputIndexes := make([]uint32, len(invalidSigs))
for i, e := range invalidSigs {
invalidInputIndexes[i] = e.InputIndex
}
var serializedTransaction bytes.Buffer
serializedTransaction.Grow(tx.SerializeSize())
err = tx.Serialize(&serializedTransaction)
if err != nil {
return nil, translateError(err)
}
resp := &pb.SignTransactionResponse{
Transaction: serializedTransaction.Bytes(),
UnsignedInputIndexes: invalidInputIndexes,
}
return resp, nil
}