lbcutil/tx.go

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2014-01-09 06:46:05 +01:00
// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package btcutil
import (
"bytes"
"io"
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"github.com/conformal/btcwire"
)
// TxIndexUnknown is the value returned for a transaction index that is unknown.
// This is typically because the transaction has not been inserted into a block
// yet.
const TxIndexUnknown = -1
// Tx defines a bitcoin transaction that provides easier and more efficient
// manipulation of raw transactions. It also memoizes the hash for the
// transaction on its first access so subsequent accesses don't have to repeat
// the relatively expensive hashing operations.
type Tx struct {
msgTx *btcwire.MsgTx // Underlying MsgTx
txSha *btcwire.ShaHash // Cached transaction hash
txIndex int // Position within a block or TxIndexUnknown
}
// MsgTx returns the underlying btcwire.MsgTx for the transaction.
func (t *Tx) MsgTx() *btcwire.MsgTx {
// Return the cached transaction.
return t.msgTx
}
// Sha returns the hash of the transaction. This is equivalent to
// calling TxSha on the underlying btcwire.MsgTx, however it caches the
// result so subsequent calls are more efficient.
func (t *Tx) Sha() *btcwire.ShaHash {
// Return the cached hash if it has already been generated.
if t.txSha != nil {
return t.txSha
}
// Generate the transaction hash. Ignore the error since TxSha can't
// currently fail.
sha, _ := t.msgTx.TxSha()
// Cache the hash and return it.
t.txSha = &sha
return &sha
}
// Index returns the saved index of the transaction within a block. This value
// will be TxIndexUnknown if it hasn't already explicitly been set.
func (t *Tx) Index() int {
return t.txIndex
}
// SetIndex sets the index of the transaction in within a block.
func (t *Tx) SetIndex(index int) {
t.txIndex = index
}
// NewTx returns a new instance of a bitcoin transaction given an underlying
// btcwire.MsgTx. See Tx.
func NewTx(msgTx *btcwire.MsgTx) *Tx {
return &Tx{
msgTx: msgTx,
txIndex: TxIndexUnknown,
}
}
// NewTxFromBytes returns a new instance of a bitcoin transaction given the
// serialized bytes. See Tx.
func NewTxFromBytes(serializedTx []byte) (*Tx, error) {
br := bytes.NewReader(serializedTx)
return NewTxFromReader(br)
}
// NewTxFromReader returns a new instance of a bitcoin transaction given a
// Reader to deserialize the transaction. See Tx.
func NewTxFromReader(r io.Reader) (*Tx, error) {
// Deserialize the bytes into a MsgTx.
var msgTx btcwire.MsgTx
err := msgTx.Deserialize(r)
if err != nil {
return nil, err
}
t := Tx{
msgTx: &msgTx,
txIndex: TxIndexUnknown,
}
return &t, nil
}