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104 lines
3.9 KiB
104 lines
3.9 KiB
#!/usr/bin/env python |
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# |
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# Electrum - lightweight Bitcoin client |
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# Copyright (C) 2011 thomasv@gitorious |
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# |
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# This program is free software: you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation, either version 3 of the License, or |
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# (at your option) any later version. |
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# |
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# This program is distributed in the hope that it will be useful, |
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# but WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with this program. If not, see <http://www.gnu.org/licenses/>. |
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from operator import itemgetter |
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from bitcoin import MIN_RELAY_TX_FEE |
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from util import NotEnoughFunds, PrintError, profiler |
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from transaction import Transaction |
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class CoinChooser(PrintError): |
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def __init__(self, wallet): |
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self.wallet = wallet |
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def fee(self, tx, fixed_fee, fee_per_kb): |
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if fixed_fee is not None: |
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return fixed_fee |
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return tx.estimated_fee(fee_per_kb) |
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def dust_threshold(self): |
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return 182 * 3 * MIN_RELAY_TX_FEE/1000 |
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def make_tx(self, coins, outputs, change_addrs, fixed_fee, fee_per_kb): |
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'''Select unspent coins to spend to pay outputs.''' |
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amount = sum(map(lambda x: x[2], outputs)) |
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total = 0 |
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inputs = [] |
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tx = Transaction.from_io(inputs, outputs) |
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fee = self.fee(tx, fixed_fee, fee_per_kb) |
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# add inputs, sorted by age |
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for item in coins: |
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v = item.get('value') |
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total += v |
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self.wallet.add_input_info(item) |
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tx.add_input(item) |
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# no need to estimate fee until we have reached desired amount |
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if total < amount + fee: |
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continue |
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fee = self.fee(tx, fixed_fee, fee_per_kb) |
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if total >= amount + fee: |
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break |
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else: |
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raise NotEnoughFunds() |
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# remove unneeded inputs. |
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removed = False |
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for item in sorted(tx.inputs, key=itemgetter('value')): |
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v = item.get('value') |
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if total - v >= amount + fee: |
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tx.inputs.remove(item) |
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total -= v |
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removed = True |
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continue |
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else: |
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break |
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if removed: |
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fee = self.fee(tx, fixed_fee, fee_per_kb) |
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for item in sorted(tx.inputs, key=itemgetter('value')): |
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v = item.get('value') |
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if total - v >= amount + fee: |
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tx.inputs.remove(item) |
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total -= v |
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fee = self.fee(tx, fixed_fee, fee_per_kb) |
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continue |
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break |
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self.print_error("using %d inputs" % len(tx.inputs)) |
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# if change is above dust threshold, add a change output. |
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change_addr = change_addrs[0] |
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change_amount = total - (amount + fee) |
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if fixed_fee is not None and change_amount > 0: |
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tx.outputs.append(('address', change_addr, change_amount)) |
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elif change_amount > self.dust_threshold(): |
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tx.outputs.append(('address', change_addr, change_amount)) |
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# recompute fee including change output |
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fee = tx.estimated_fee(fee_per_kb) |
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# remove change output |
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tx.outputs.pop() |
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# if change is still above dust threshold, re-add change output. |
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change_amount = total - (amount + fee) |
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if change_amount > self.dust_threshold(): |
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tx.outputs.append(('address', change_addr, change_amount)) |
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self.print_error('change', change_amount) |
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else: |
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self.print_error('not keeping dust', change_amount) |
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else: |
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self.print_error('not keeping dust', change_amount) |
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return tx
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