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124 lines
2.9 KiB
Go
124 lines
2.9 KiB
Go
package utils
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import (
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"bytes"
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"errors"
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"fmt"
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"os"
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"github.com/btcsuite/btcd/chaincfg"
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"github.com/btcsuite/btcutil"
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"github.com/lightningnetwork/lnd/lntypes"
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"github.com/lightningnetwork/lnd/zpay32"
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"github.com/btcsuite/btcd/wire"
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)
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const (
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// FeeRateTotalParts defines the granularity of the fee rate.
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FeeRateTotalParts = 1e6
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)
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// ShortHash returns a shortened version of the hash suitable for use in
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// logging.
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func ShortHash(hash *lntypes.Hash) string {
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return hash.String()[:6]
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}
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// EncodeTx encodes a tx to raw bytes.
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func EncodeTx(tx *wire.MsgTx) ([]byte, error) {
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var buffer bytes.Buffer
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err := tx.BtcEncode(&buffer, 0, wire.WitnessEncoding)
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if err != nil {
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return nil, err
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}
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rawTx := buffer.Bytes()
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return rawTx, nil
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}
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// DecodeTx decodes raw tx bytes.
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func DecodeTx(rawTx []byte) (*wire.MsgTx, error) {
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tx := wire.MsgTx{}
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r := bytes.NewReader(rawTx)
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err := tx.BtcDecode(r, 0, wire.WitnessEncoding)
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if err != nil {
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return nil, err
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}
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return &tx, nil
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}
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// GetInvoiceAmt gets the invoice amount. It requires an amount to be specified.
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func GetInvoiceAmt(params *chaincfg.Params,
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payReq string) (btcutil.Amount, error) {
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swapPayReq, err := zpay32.Decode(
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payReq, params,
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)
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if err != nil {
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return 0, err
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}
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if swapPayReq.MilliSat == nil {
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return 0, errors.New("no amount in invoice")
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}
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return swapPayReq.MilliSat.ToSatoshis(), nil
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}
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// FileExists returns true if the file exists, and false otherwise.
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func FileExists(path string) bool {
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if _, err := os.Stat(path); err != nil {
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if os.IsNotExist(err) {
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return false
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}
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}
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return true
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}
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// ChainParamsFromNetwork returns chain parameters based on a network name.
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func ChainParamsFromNetwork(network string) (*chaincfg.Params, error) {
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switch network {
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case "mainnet":
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return &chaincfg.MainNetParams, nil
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case "testnet":
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return &chaincfg.TestNet3Params, nil
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case "regtest":
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return &chaincfg.RegressionNetParams, nil
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case "simnet":
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return &chaincfg.SimNetParams, nil
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default:
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return nil, errors.New("unknown network")
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}
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}
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// GetScriptOutput locates the given script in the outputs of a transaction and
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// returns its outpoint and value.
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func GetScriptOutput(htlcTx *wire.MsgTx, scriptHash []byte) (
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*wire.OutPoint, btcutil.Amount, error) {
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for idx, output := range htlcTx.TxOut {
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if bytes.Equal(output.PkScript, scriptHash) {
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return &wire.OutPoint{
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Hash: htlcTx.TxHash(),
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Index: uint32(idx),
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}, btcutil.Amount(output.Value), nil
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}
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}
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return nil, 0, fmt.Errorf("cannot determine outpoint")
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}
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// CalcFee returns the swap fee for a given swap amount.
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func CalcFee(amount, feeBase btcutil.Amount, feeRate int64) btcutil.Amount {
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return feeBase + amount*btcutil.Amount(feeRate)/
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btcutil.Amount(FeeRateTotalParts)
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}
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// FeeRateAsPercentage converts a feerate to a percentage.
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func FeeRateAsPercentage(feeRate int64) float64 {
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return float64(feeRate) / (FeeRateTotalParts / 100)
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}
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