// minimumFee calculates the minimum fee required for a transaction.
// If allowFree is true, a fee may be zero so long as the entire
// transaction has a serialized length less than 1 kilobyte
// and none of the outputs contain a value less than 1 bitcent.
// Otherwise, the fee will be calculated using TxFeeIncrement,
// incrementing the fee for each kilobyte of transaction.
func minimumFee(tx *btcwire.MsgTx, allowFree bool) btcutil.Amount {
txLen := tx.SerializeSize()
TxFeeIncrement.Lock()
incr := TxFeeIncrement.i
TxFeeIncrement.Unlock()
fee := btcutil.Amount(int64(1+txLen/1000) * int64(incr))
if allowFree && txLen < 1000 {
fee = 0
}
if fee < incr {
for _, txOut := range tx.TxOut {
if txOut.Value < btcutil.SatoshiPerBitcent {
return incr
}
}
}
max := btcutil.Amount(btcutil.MaxSatoshi)
if fee < 0 || fee > max {
fee = max
}
return fee
}
// 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 *btcwire.MsgTx, inputs []btcjson.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())
}
id := c.NextID()
cmd, err := btcjson.NewSignRawTransactionCmd(id, txHex, inputs)
if err != nil {
return newFutureError(err)
}
return c.sendCmd(cmd)
}
// toHex converts a msgTx into a hex string.
func ToHex(tx *btcwire.MsgTx) string {
buf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))
tx.Serialize(buf)
txHex := hex.EncodeToString(buf.Bytes())
return txHex
}