func mkGetScript(scripts map[string][]byte) txscript.ScriptDB {
if scripts == nil {
return txscript.ScriptClosure(func(addr btcutil.Address) (
[]byte, error) {
return nil, errors.New("nope")
})
}
return txscript.ScriptClosure(func(addr btcutil.Address) ([]byte,
error) {
script, ok := scripts[addr.EncodeAddress()]
if !ok {
return nil, errors.New("nope")
}
return script, nil
})
}
func (w *LibbitcoinWallet) Spend(amount int64, addr btc.Address, feeLevel bitcoin.FeeLevel) error {
// Check for dust
script, _ := txscript.PayToAddrScript(addr)
if txrules.IsDustAmount(btc.Amount(amount), len(script), txrules.DefaultRelayFeePerKb) {
return errors.New("Amount is below dust threshold")
}
var additionalPrevScripts map[wire.OutPoint][]byte
var additionalKeysByAddress map[string]*btc.WIF
// Create input source
coinMap := w.gatherCoins()
coins := make([]coinset.Coin, 0, len(coinMap))
for k := range coinMap {
coins = append(coins, k)
}
inputSource := func(target btc.Amount) (total btc.Amount, inputs []*wire.TxIn, scripts [][]byte, err error) {
// TODO: maybe change the coin selection algorithm? We're using min coins right now because
// TODO: we don't know the number of confirmations on each coin without querying the libbitcoin server.
coinSelector := coinset.MinNumberCoinSelector{MaxInputs: 10000, MinChangeAmount: btc.Amount(10000)}
coins, err := coinSelector.CoinSelect(target, coins)
if err != nil {
return total, inputs, scripts, errors.New("insuffient funds")
}
additionalPrevScripts = make(map[wire.OutPoint][]byte)
additionalKeysByAddress = make(map[string]*btc.WIF)
for _, c := range coins.Coins() {
total += c.Value()
outpoint := wire.NewOutPoint(c.Hash(), c.Index())
in := wire.NewTxIn(outpoint, []byte{})
in.Sequence = 0 // Opt-in RBF so we can bump fees
inputs = append(inputs, in)
additionalPrevScripts[*outpoint] = c.PkScript()
key := coinMap[c]
addr, _ := btc.NewAddressPubKey(key.PublicKey().Key, w.params)
pk, _ := btcec.PrivKeyFromBytes(btcec.S256(), key.Key)
wif, _ := btc.NewWIF(pk, w.params, true)
additionalKeysByAddress[addr.AddressPubKeyHash().EncodeAddress()] = wif
}
return total, inputs, scripts, nil
}
// Get the fee per kilobyte
feePerKB := int64(w.getFeePerByte(feeLevel)) * 1000
// outputs
out := wire.NewTxOut(amount, script)
// Create change source
changeSource := func() ([]byte, error) {
addr := w.GetCurrentAddress(bitcoin.CHANGE)
script, err := txscript.PayToAddrScript(addr)
if err != nil {
return []byte{}, err
}
return script, nil
}
authoredTx, err := txauthor.NewUnsignedTransaction([]*wire.TxOut{out}, btc.Amount(feePerKB), inputSource, changeSource)
if err != nil {
return err
}
// BIP 69 sorting
txsort.InPlaceSort(authoredTx.Tx)
// Sign tx
getKey := txscript.KeyClosure(func(addr btc.Address) (
*btcec.PrivateKey, bool, error) {
addrStr := addr.EncodeAddress()
wif := additionalKeysByAddress[addrStr]
return wif.PrivKey, wif.CompressPubKey, nil
})
getScript := txscript.ScriptClosure(func(
addr btc.Address) ([]byte, error) {
return []byte{}, nil
})
for i, txIn := range authoredTx.Tx.TxIn {
prevOutScript := additionalPrevScripts[txIn.PreviousOutPoint]
script, err := txscript.SignTxOutput(w.params,
authoredTx.Tx, i, prevOutScript, txscript.SigHashAll, getKey,
getScript, txIn.SignatureScript)
if err != nil {
return errors.New("Failed to sign transaction")
}
txIn.SignatureScript = script
}
// Broadcast tx to bitcoin network
serializedTx := new(bytes.Buffer)
authoredTx.Tx.Serialize(serializedTx)
w.Client.Broadcast(serializedTx.Bytes(), func(i interface{}, err error) {
if err == nil {
log.Infof("Broadcast tx %s to bitcoin network\n", authoredTx.Tx.TxSha().String())
} else {
log.Errorf("Failed to broadcast tx, reason: %s\n", err)
}
})
// Update the db
w.ProcessTransaction(btc.NewTx(authoredTx.Tx), 0)
return nil
}