Golang MsgTx.SerializeSize方法代码示例

// 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 int32) 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)
}

// NewTxRecordFromMsgTx creates a new transaction record that may be inserted
// into the store.
func NewTxRecordFromMsgTx(msgTx *wire.MsgTx, received time.Time) (*TxRecord, error) {
	buf := bytes.NewBuffer(make([]byte, 0, msgTx.SerializeSize()))
	err := msgTx.Serialize(buf)
	if err != nil {
		str := "failed to serialize transaction"
		return nil, storeError(ErrInput, str, err)
	}
	rec := &TxRecord{
		MsgTx:        *msgTx,
		Received:     received,
		SerializedTx: buf.Bytes(),
		Hash:         msgTx.TxSha(),
	}

	return rec, nil
}

// 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
}

// TxToString prints out some info about a transaction. for testing / debugging
func TxToString(tx *wire.MsgTx) string {
	str := fmt.Sprintf("size %d vsize %d wsize %d locktime %d txid %s\n",
		tx.SerializeSize(), blockchain.GetTxVirtualSize(btcutil.NewTx(tx)),
		tx.SerializeSize(), tx.LockTime, tx.TxSha().String())
	for i, in := range tx.TxIn {
		str += fmt.Sprintf("Input %d spends %s\n", i, in.PreviousOutPoint.String())
		str += fmt.Sprintf("\tSigScript: %x\n", in.SignatureScript)
		for j, wit := range in.Witness {
			str += fmt.Sprintf("\twitness %d: %x\n", j, wit)
		}
	}
	for i, out := range tx.TxOut {
		if out != nil {
			str += fmt.Sprintf("output %d script: %x amt: %d\n",
				i, out.PkScript, out.Value)
		} else {
			str += fmt.Sprintf("output %d nil (WARNING)\n", i)
		}
	}
	return str
}

// fundTx attempts to fund a transaction sending amt bitcoin. The coins are
// selected such that the final amount spent pays enough fees as dictated by
// the passed fee rate. The passed fee rate should be expressed in
// satoshis-per-byte.
//
// NOTE: The memWallet's mutex must be held when this function is called.
func (m *memWallet) fundTx(tx *wire.MsgTx, amt btcutil.Amount, feeRate btcutil.Amount) error {
	const (
		// spendSize is the largest number of bytes of a sigScript
		// which spends a p2pkh output: OP_DATA_73 <sig> OP_DATA_33 <pubkey>
		spendSize = 1 + 73 + 1 + 33
	)

	var (
		amtSelected btcutil.Amount
		txSize      int
	)

	for outPoint, utxo := range m.utxos {
		// Skip any outputs that are still currently immature or are
		// currently locked.
		if !utxo.isMature(m.currentHeight) || utxo.isLocked {
			continue
		}

		amtSelected += utxo.value

		// Add the selected output to the transaction, updating the
		// current tx size while accounting for the size of the future
		// sigScript.
		tx.AddTxIn(wire.NewTxIn(&outPoint, nil, nil))
		txSize = tx.SerializeSize() + spendSize*len(tx.TxIn)

		// Calculate the fee required for the txn at this point
		// observing the specified fee rate. If we don't have enough
		// coins from he current amount selected to pay the fee, then
		// continue to grab more coins.
		reqFee := btcutil.Amount(txSize * int(feeRate))
		if amtSelected-reqFee < amt {
			continue
		}

		// If we have any change left over, then add an additional
		// output to the transaction reserved for change.
		changeVal := amtSelected - amt - reqFee
		if changeVal > 0 {
			addr, err := m.newAddress()
			if err != nil {
				return err
			}
			pkScript, err := txscript.PayToAddrScript(addr)
			if err != nil {
				return err
			}
			changeOutput := &wire.TxOut{
				Value:    int64(changeVal),
				PkScript: pkScript,
			}
			tx.AddTxOut(changeOutput)
		}

		return nil
	}

	// If we've reached this point, then coin selection failed due to an
	// insufficient amount of coins.
	return fmt.Errorf("not enough funds for coin selection")
}