示例#1
0
// CalculateAddressBalance sums the amounts of all unspent transaction
// outputs to a single address's pubkey hash and returns the balance
// as a float64.
//
// If confirmations is 0, all UTXOs, even those not present in a
// block (height -1), will be used to get the balance.  Otherwise,
// a UTXO must be in a block.  If confirmations is 1 or greater,
// the balance will be calculated based on how many how many blocks
// include a UTXO.
func (a *Account) CalculateAddressBalance(addr *btcutil.AddressPubKeyHash, confirms int) float64 {
	bs, err := GetCurBlock()
	if bs.Height == int32(btcutil.BlockHeightUnknown) || err != nil {
		return 0.
	}

	var bal uint64 // Measured in satoshi
	for _, u := range a.UtxoStore {
		// Utxos not yet in blocks (height -1) should only be
		// added if confirmations is 0.
		if confirmed(confirms, u.Height, bs.Height) {
			if bytes.Equal(addr.ScriptAddress(), u.AddrHash[:]) {
				bal += u.Amt
			}
		}
	}
	return float64(bal) / float64(btcutil.SatoshiPerBitcoin)
}
示例#2
0
// txToPairs creates a raw transaction sending the amounts for each
// address/amount pair and fee to each address and the miner.  minconf
// specifies the minimum number of confirmations required before an
// unspent output is eligible for spending. Leftover input funds not sent
// to addr or as a fee for the miner are sent to a newly generated
// address. If change is needed to return funds back to an owned
// address, changeUtxo will point to a unconfirmed (height = -1, zeroed
// block hash) Utxo.  ErrInsufficientFunds is returned if there are not
// enough eligible unspent outputs to create the transaction.
func (a *Account) txToPairs(pairs map[string]int64, minconf int) (*CreatedTx, error) {
	// Create a new transaction which will include all input scripts.
	msgtx := btcwire.NewMsgTx()

	// Calculate minimum amount needed for inputs.
	var amt int64
	for _, v := range pairs {
		// Error out if any amount is negative.
		if v <= 0 {
			return nil, ErrNonPositiveAmount
		}
		amt += v
	}

	// outputs is a tx.Pair slice representing each output that is created
	// by the transaction.
	outputs := make([]tx.Pair, 0, len(pairs)+1)

	// Add outputs to new tx.
	for addrStr, amt := range pairs {
		addr, err := btcutil.DecodeAddr(addrStr)
		if err != nil {
			return nil, fmt.Errorf("cannot decode address: %s", err)
		}

		// Add output to spend amt to addr.
		pkScript, err := btcscript.PayToAddrScript(addr)
		if err != nil {
			return nil, fmt.Errorf("cannot create txout script: %s", err)
		}
		txout := btcwire.NewTxOut(int64(amt), pkScript)
		msgtx.AddTxOut(txout)

		// Create amount, address pair and add to outputs.
		out := tx.Pair{
			Amount:     amt,
			PubkeyHash: addr.ScriptAddress(),
		}
		outputs = append(outputs, out)
	}

	// Get current block's height and hash.
	bs, err := GetCurBlock()
	if err != nil {
		return nil, err
	}

	// Make a copy of msgtx before any inputs are added.  This will be
	// used as a starting point when trying a fee and starting over with
	// a higher fee if not enough was originally chosen.
	txNoInputs := msgtx.Copy()

	// These are nil/zeroed until a change address is needed, and reused
	// again in case a change utxo has already been chosen.
	var changeAddr *btcutil.AddressPubKeyHash

	var btcspent int64
	var selectedInputs []*tx.Utxo
	var finalChangeUtxo *tx.Utxo

	// Get the number of satoshis to increment fee by when searching for
	// the minimum tx fee needed.
	fee := int64(0)
	for {
		msgtx = txNoInputs.Copy()

		// Select unspent outputs to be used in transaction based on the amount
		// neededing to sent, and the current fee estimation.
		inputs, btcin, err := selectInputs(a.UtxoStore, uint64(amt+fee),
			minconf)
		if err != nil {
			return nil, err
		}

		// Check if there are leftover unspent outputs, and return coins back to
		// a new address we own.
		var changeUtxo *tx.Utxo
		change := btcin - uint64(amt+fee)
		if change > 0 {
			// Create a new address to spend leftover outputs to.

			// Get a new change address if one has not already been found.
			if changeAddr == nil {
				changeAddr, err = a.ChangeAddress(&bs, cfg.KeypoolSize)
				if err != nil {
					return nil, fmt.Errorf("failed to get next address: %s", err)
				}

				// Mark change address as belonging to this account.
				MarkAddressForAccount(changeAddr.EncodeAddress(), a.Name())
			}

			// Spend change.
			pkScript, err := btcscript.PayToAddrScript(changeAddr)
			if err != nil {
				return nil, fmt.Errorf("cannot create txout script: %s", err)
			}
			msgtx.AddTxOut(btcwire.NewTxOut(int64(change), pkScript))

			changeUtxo = &tx.Utxo{
				Amt: change,
				Out: tx.OutPoint{
					// Hash is unset (zeroed) here and must be filled in
					// with the transaction hash of the complete
					// transaction.
					Index: uint32(len(pairs)),
				},
				Height:    -1,
				Subscript: pkScript,
			}
			copy(changeUtxo.AddrHash[:], changeAddr.ScriptAddress())
		}

		// Selected unspent outputs become new transaction's inputs.
		for _, ip := range inputs {
			msgtx.AddTxIn(btcwire.NewTxIn((*btcwire.OutPoint)(&ip.Out), nil))
		}
		for i, ip := range inputs {
			// Error is ignored as the length and network checks can never fail
			// for these inputs.
			addr, _ := btcutil.NewAddressPubKeyHash(ip.AddrHash[:],
				a.Wallet.Net())
			privkey, err := a.AddressKey(addr)
			if err == wallet.ErrWalletLocked {
				return nil, wallet.ErrWalletLocked
			} else if err != nil {
				return nil, fmt.Errorf("cannot get address key: %v", err)
			}
			ai, err := a.AddressInfo(addr)
			if err != nil {
				return nil, fmt.Errorf("cannot get address info: %v", err)
			}

			sigscript, err := btcscript.SignatureScript(msgtx, i,
				ip.Subscript, btcscript.SigHashAll, privkey,
				ai.Compressed)
			if err != nil {
				return nil, fmt.Errorf("cannot create sigscript: %s", err)
			}
			msgtx.TxIn[i].SignatureScript = sigscript
		}

		noFeeAllowed := false
		if !cfg.DisallowFree {
			noFeeAllowed = allowFree(bs.Height, inputs, msgtx.SerializeSize())
		}
		if minFee := minimumFee(msgtx, noFeeAllowed); fee < minFee {
			fee = minFee
		} else {
			// Fill Tx hash of change outpoint with transaction hash.
			if changeUtxo != nil {
				txHash, err := msgtx.TxSha()
				if err != nil {
					return nil, fmt.Errorf("cannot create transaction hash: %s", err)
				}
				copy(changeUtxo.Out.Hash[:], txHash[:])

				// Add change to outputs.
				out := tx.Pair{
					Amount:     int64(change),
					PubkeyHash: changeAddr.ScriptAddress(),
					Change:     true,
				}
				outputs = append(outputs, out)

				finalChangeUtxo = changeUtxo
			}

			selectedInputs = inputs

			btcspent = int64(btcin)

			break
		}
	}

	// Validate msgtx before returning the raw transaction.
	flags := btcscript.ScriptCanonicalSignatures
	bip16 := time.Now().After(btcscript.Bip16Activation)
	if bip16 {
		flags |= btcscript.ScriptBip16
	}
	for i, txin := range msgtx.TxIn {
		engine, err := btcscript.NewScript(txin.SignatureScript,
			selectedInputs[i].Subscript, i, msgtx, flags)
		if err != nil {
			return nil, fmt.Errorf("cannot create script engine: %s", err)
		}
		if err = engine.Execute(); err != nil {
			return nil, fmt.Errorf("cannot validate transaction: %s", err)
		}
	}

	txid, err := msgtx.TxSha()
	if err != nil {
		return nil, fmt.Errorf("cannot create txid for created tx: %v", err)
	}

	buf := new(bytes.Buffer)
	msgtx.BtcEncode(buf, btcwire.ProtocolVersion)
	info := &CreatedTx{
		rawTx:      buf.Bytes(),
		txid:       txid,
		time:       time.Now(),
		inputs:     selectedInputs,
		outputs:    outputs,
		btcspent:   btcspent,
		fee:        fee,
		changeAddr: changeAddr,
		changeUtxo: finalChangeUtxo,
	}
	return info, nil
}