Simplify interface to make_tx in coin chooser

Makes the coin chooser code simpler and easier to understand.
This commit is contained in:
Neil Booth 2015-11-28 22:08:00 +09:00
parent 90dee43998
commit a6ea9a0c71
2 changed files with 33 additions and 29 deletions

View File

@ -27,21 +27,17 @@ class CoinChooser(PrintError):
def __init__(self, wallet):
self.wallet = wallet
def fee(self, tx, fixed_fee, fee_per_kb):
if fixed_fee is not None:
return fixed_fee
return tx.estimated_fee(fee_per_kb)
def dust_threshold(self):
return 182 * 3 * MIN_RELAY_TX_FEE/1000
def make_tx(self, coins, outputs, change_addrs, fixed_fee, fee_per_kb):
'''Select unspent coins to spend to pay outputs.'''
def make_tx(self, coins, outputs, change_addrs, fee_estimator,
dust_threshold):
'''Select unspent coins to spend to pay outputs. If the change is
greater than dust_threshold (after adding the change output to
the transaction) it is kept, otherwise none is sent and it is
added to the transaction fee.'''
amount = sum(map(lambda x: x[2], outputs))
total = 0
inputs = []
tx = Transaction.from_io(inputs, outputs)
fee = self.fee(tx, fixed_fee, fee_per_kb)
fee = fee_estimator(tx)
# add inputs, sorted by age
for item in coins:
v = item.get('value')
@ -51,7 +47,7 @@ class CoinChooser(PrintError):
# no need to estimate fee until we have reached desired amount
if total < amount + fee:
continue
fee = self.fee(tx, fixed_fee, fee_per_kb)
fee = fee_estimator(tx)
if total >= amount + fee:
break
else:
@ -69,13 +65,13 @@ class CoinChooser(PrintError):
else:
break
if removed:
fee = self.fee(tx, fixed_fee, fee_per_kb)
fee = fee_estimator(tx)
for item in sorted(tx.inputs, key=itemgetter('value')):
v = item.get('value')
if total - v >= amount + fee:
tx.inputs.remove(item)
total -= v
fee = self.fee(tx, fixed_fee, fee_per_kb)
fee = fee_estimator(tx)
continue
break
self.print_error("using %d inputs" % len(tx.inputs))
@ -83,22 +79,21 @@ class CoinChooser(PrintError):
# if change is above dust threshold, add a change output.
change_addr = change_addrs[0]
change_amount = total - (amount + fee)
if fixed_fee is not None and change_amount > 0:
# See if change would still be greater than dust after adding
# the change to the transaction
if change_amount > dust_threshold:
tx.outputs.append(('address', change_addr, change_amount))
elif change_amount > self.dust_threshold():
tx.outputs.append(('address', change_addr, change_amount))
# recompute fee including change output
fee = tx.estimated_fee(fee_per_kb)
fee = fee_estimator(tx)
# remove change output
tx.outputs.pop()
# if change is still above dust threshold, re-add change output.
change_amount = total - (amount + fee)
if change_amount > self.dust_threshold():
tx.outputs.append(('address', change_addr, change_amount))
self.print_error('change', change_amount)
else:
self.print_error('not keeping dust', change_amount)
else:
# If change is still above dust threshold, keep the change.
if change_amount > dust_threshold:
tx.outputs.append(('address', change_addr, change_amount))
self.print_error('change', change_amount)
elif change_amount:
self.print_error('not keeping dust', change_amount)
return tx

View File

@ -905,8 +905,6 @@ class Abstract_Wallet(PrintError):
if type == 'address':
assert is_address(data), "Address " + data + " is invalid!"
fee_per_kb = self.fee_per_kb(config)
# change address
if change_addr:
change_addrs = [change_addr]
@ -926,9 +924,20 @@ class Abstract_Wallet(PrintError):
else:
change_addrs = [address]
fee_per_kb = self.fee_per_kb(config)
def fee_estimator(tx):
if fixed_fee is not None:
return fixed_fee
return tx.estimated_fee(fee_per_kb)
# If a fixed fee is specified, keep even dust change
dust_threshold = 182 * 3 * MIN_RELAY_TX_FEE / 1000
if fixed_fee is None:
dust_threshold = 0
# Let the coin chooser select the coins to spend
tx = self.coin_chooser.make_tx(coins, outputs, change_addrs,
fixed_fee, fee_per_kb)
fee_estimator, dust_threshold)
# Sort the inputs and outputs deterministically
tx.BIP_LI01_sort()