lbry-sdk/torba/basetransaction.py
2018-10-04 19:27:39 -04:00

500 lines
16 KiB
Python

import logging
import typing
from typing import List, Iterable, Optional
from binascii import hexlify
from twisted.internet import defer
from torba.basescript import BaseInputScript, BaseOutputScript
from torba.baseaccount import BaseAccount
from torba.constants import COIN, NULL_HASH32
from torba.bcd_data_stream import BCDataStream
from torba.hash import sha256, TXRef, TXRefImmutable
from torba.util import ReadOnlyList
if typing.TYPE_CHECKING:
from torba import baseledger
log = logging.getLogger()
class TXRefMutable(TXRef):
__slots__ = ('tx',)
def __init__(self, tx: 'BaseTransaction') -> None:
super().__init__()
self.tx = tx
@property
def id(self):
if self._id is None:
self._id = hexlify(self.hash[::-1]).decode()
return self._id
@property
def hash(self):
if self._hash is None:
self._hash = sha256(sha256(self.tx.raw))
return self._hash
def reset(self):
self._id = None
self._hash = None
class TXORef:
__slots__ = 'tx_ref', 'position'
def __init__(self, tx_ref: TXRef, position: int) -> None:
self.tx_ref = tx_ref
self.position = position
@property
def id(self):
return '{}:{}'.format(self.tx_ref.id, self.position)
@property
def is_null(self):
return self.tx_ref.is_null
@property
def txo(self) -> Optional['BaseOutput']:
return None
class TXORefResolvable(TXORef):
__slots__ = ('_txo',)
def __init__(self, txo: 'BaseOutput') -> None:
assert txo.tx_ref is not None
assert txo.position is not None
super().__init__(txo.tx_ref, txo.position)
self._txo = txo
@property
def txo(self):
return self._txo
class InputOutput:
__slots__ = 'tx_ref', 'position'
def __init__(self, tx_ref: TXRef = None, position: int = None) -> None:
self.tx_ref = tx_ref
self.position = position
@property
def size(self) -> int:
""" Size of this input / output in bytes. """
stream = BCDataStream()
self.serialize_to(stream)
return len(stream.get_bytes())
def get_fee(self, ledger):
return self.size * ledger.fee_per_byte
def serialize_to(self, stream, alternate_script=None):
raise NotImplementedError
class BaseInput(InputOutput):
script_class = BaseInputScript
NULL_SIGNATURE = b'\x00'*72
NULL_PUBLIC_KEY = b'\x00'*33
__slots__ = 'txo_ref', 'sequence', 'coinbase', 'script'
def __init__(self, txo_ref: TXORef, script: BaseInputScript, sequence: int = 0xFFFFFFFF,
tx_ref: TXRef = None, position: int = None) -> None:
super().__init__(tx_ref, position)
self.txo_ref = txo_ref
self.sequence = sequence
self.coinbase = script if txo_ref.is_null else None
self.script = script if not txo_ref.is_null else None
@property
def is_coinbase(self):
return self.coinbase is not None
@classmethod
def spend(cls, txo: 'BaseOutput') -> 'BaseInput':
""" Create an input to spend the output."""
assert txo.script.is_pay_pubkey_hash, 'Attempting to spend unsupported output.'
script = cls.script_class.redeem_pubkey_hash(cls.NULL_SIGNATURE, cls.NULL_PUBLIC_KEY)
return cls(txo.ref, script)
@property
def amount(self) -> int:
""" Amount this input adds to the transaction. """
if self.txo_ref.txo is None:
raise ValueError('Cannot resolve output to get amount.')
return self.txo_ref.txo.amount
@property
def is_my_account(self) -> Optional[bool]:
""" True if the output this input spends is yours. """
if self.txo_ref.txo is None:
return False
return self.txo_ref.txo.is_my_account
@classmethod
def deserialize_from(cls, stream):
tx_ref = TXRefImmutable.from_hash(stream.read(32))
position = stream.read_uint32()
script = stream.read_string()
sequence = stream.read_uint32()
return cls(
TXORef(tx_ref, position),
cls.script_class(script) if not tx_ref.is_null else script,
sequence
)
def serialize_to(self, stream, alternate_script=None):
stream.write(self.txo_ref.tx_ref.hash)
stream.write_uint32(self.txo_ref.position)
if alternate_script is not None:
stream.write_string(alternate_script)
else:
if self.is_coinbase:
stream.write_string(self.coinbase)
else:
stream.write_string(self.script.source)
stream.write_uint32(self.sequence)
class BaseOutputEffectiveAmountEstimator:
__slots__ = 'txo', 'txi', 'fee', 'effective_amount'
def __init__(self, ledger: 'baseledger.BaseLedger', txo: 'BaseOutput') -> None:
self.txo = txo
self.txi = ledger.transaction_class.input_class.spend(txo)
self.fee: int = self.txi.get_fee(ledger)
self.effective_amount: int = txo.amount - self.fee
def __lt__(self, other):
return self.effective_amount < other.effective_amount
class BaseOutput(InputOutput):
script_class = BaseOutputScript
estimator_class = BaseOutputEffectiveAmountEstimator
__slots__ = 'amount', 'script', 'is_change', 'is_my_account'
def __init__(self, amount: int, script: BaseOutputScript,
tx_ref: TXRef = None, position: int = None,
is_change: Optional[bool] = None, is_my_account: Optional[bool] = None
) -> None:
super().__init__(tx_ref, position)
self.amount = amount
self.script = script
self.is_change = is_change
self.is_my_account = is_my_account
def update_annotations(self, annotated):
if annotated is None:
self.is_change = False
self.is_my_account = False
else:
self.is_change = annotated.is_change
self.is_my_account = annotated.is_my_account
@property
def ref(self):
return TXORefResolvable(self)
@property
def id(self):
return self.ref.id
def get_address(self, ledger):
return ledger.hash160_to_address(
self.script.values['pubkey_hash']
)
def get_estimator(self, ledger):
return self.estimator_class(ledger, self)
@classmethod
def pay_pubkey_hash(cls, amount, pubkey_hash):
return cls(amount, cls.script_class.pay_pubkey_hash(pubkey_hash))
@classmethod
def deserialize_from(cls, stream):
return cls(
amount=stream.read_uint64(),
script=cls.script_class(stream.read_string())
)
def serialize_to(self, stream, alternate_script=None):
stream.write_uint64(self.amount)
stream.write_string(self.script.source)
class BaseTransaction:
input_class = BaseInput
output_class = BaseOutput
def __init__(self, raw=None, version: int = 1, locktime: int = 0, is_verified: bool = False,
height: int = -1, position: int = -1) -> None:
self._raw = raw
self.ref = TXRefMutable(self)
self.version = version
self.locktime = locktime
self._inputs: List[BaseInput] = []
self._outputs: List[BaseOutput] = []
self.is_verified = is_verified
self.height = height
self.position = position
if raw is not None:
self._deserialize()
@property
def id(self):
return self.ref.id
@property
def hash(self):
return self.ref.hash
@property
def raw(self):
if self._raw is None:
self._raw = self._serialize()
return self._raw
def _reset(self):
self._raw = None
self.ref.reset()
@property
def inputs(self) -> ReadOnlyList[BaseInput]:
return ReadOnlyList(self._inputs)
@property
def outputs(self) -> ReadOnlyList[BaseOutput]:
return ReadOnlyList(self._outputs)
def _add(self, new_ios: Iterable[InputOutput], existing_ios: List) -> 'BaseTransaction':
for txio in new_ios:
txio.tx_ref = self.ref
txio.position = len(existing_ios)
existing_ios.append(txio)
self._reset()
return self
def add_inputs(self, inputs: Iterable[BaseInput]) -> 'BaseTransaction':
return self._add(inputs, self._inputs)
def add_outputs(self, outputs: Iterable[BaseOutput]) -> 'BaseTransaction':
return self._add(outputs, self._outputs)
@property
def size(self) -> int:
""" Size in bytes of the entire transaction. """
return len(self.raw)
@property
def base_size(self) -> int:
""" Size of transaction without inputs or outputs in bytes. """
return (
self.size
- sum(txi.size for txi in self._inputs)
- sum(txo.size for txo in self._outputs)
)
@property
def input_sum(self):
return sum(i.amount for i in self.inputs if i.txo_ref.txo is not None)
@property
def output_sum(self):
return sum(o.amount for o in self.outputs)
@property
def net_account_balance(self) -> int:
balance = 0
for txi in self.inputs:
if txi.txo_ref.txo is None:
continue
if txi.is_my_account is None:
raise ValueError(
"Cannot access net_account_balance if inputs/outputs do not "
"have is_my_account set properly."
)
elif txi.is_my_account:
balance -= txi.amount
for txo in self.outputs:
if txo.is_my_account is None:
raise ValueError(
"Cannot access net_account_balance if inputs/outputs do not "
"have is_my_account set properly."
)
elif txo.is_my_account:
balance += txo.amount
return balance
@property
def fee(self) -> int:
return self.input_sum - self.output_sum
def get_base_fee(self, ledger) -> int:
""" Fee for base tx excluding inputs and outputs. """
return self.base_size * ledger.fee_per_byte
def get_effective_input_sum(self, ledger) -> int:
""" Sum of input values *minus* the cost involved to spend them. """
return sum(txi.amount - txi.get_fee(ledger) for txi in self._inputs)
def get_total_output_sum(self, ledger) -> int:
""" Sum of output values *plus* the cost involved to spend them. """
return sum(txo.amount + txo.get_fee(ledger) for txo in self._outputs)
def _serialize(self, with_inputs: bool = True) -> bytes:
stream = BCDataStream()
stream.write_uint32(self.version)
if with_inputs:
stream.write_compact_size(len(self._inputs))
for txin in self._inputs:
txin.serialize_to(stream)
stream.write_compact_size(len(self._outputs))
for txout in self._outputs:
txout.serialize_to(stream)
stream.write_uint32(self.locktime)
return stream.get_bytes()
def _serialize_for_signature(self, signing_input: int) -> bytes:
stream = BCDataStream()
stream.write_uint32(self.version)
stream.write_compact_size(len(self._inputs))
for i, txin in enumerate(self._inputs):
if signing_input == i:
assert txin.txo_ref.txo is not None
txin.serialize_to(stream, txin.txo_ref.txo.script.source)
else:
txin.serialize_to(stream, b'')
stream.write_compact_size(len(self._outputs))
for txout in self._outputs:
txout.serialize_to(stream)
stream.write_uint32(self.locktime)
stream.write_uint32(self.signature_hash_type(1)) # signature hash type: SIGHASH_ALL
return stream.get_bytes()
def _deserialize(self):
if self._raw is not None:
stream = BCDataStream(self._raw)
self.version = stream.read_uint32()
input_count = stream.read_compact_size()
self.add_inputs([
self.input_class.deserialize_from(stream) for _ in range(input_count)
])
output_count = stream.read_compact_size()
self.add_outputs([
self.output_class.deserialize_from(stream) for _ in range(output_count)
])
self.locktime = stream.read_uint32()
@classmethod
def ensure_all_have_same_ledger(cls, funding_accounts: Iterable[BaseAccount],
change_account: BaseAccount = None) -> 'baseledger.BaseLedger':
ledger = None
for account in funding_accounts:
if ledger is None:
ledger = account.ledger
if ledger != account.ledger:
raise ValueError(
'All funding accounts used to create a transaction must be on the same ledger.'
)
if change_account is not None and change_account.ledger != ledger:
raise ValueError('Change account must use same ledger as funding accounts.')
if ledger is None:
raise ValueError('No ledger found.')
return ledger
@classmethod
@defer.inlineCallbacks
def create(cls, inputs: Iterable[BaseInput], outputs: Iterable[BaseOutput],
funding_accounts: Iterable[BaseAccount], change_account: BaseAccount):
""" Find optimal set of inputs when only outputs are provided; add change
outputs if only inputs are provided or if inputs are greater than outputs. """
tx = cls() \
.add_inputs(inputs) \
.add_outputs(outputs)
ledger = cls.ensure_all_have_same_ledger(funding_accounts, change_account)
# value of the outputs plus associated fees
cost = (
tx.get_base_fee(ledger) +
tx.get_total_output_sum(ledger)
)
# value of the inputs less the cost to spend those inputs
payment = tx.get_effective_input_sum(ledger)
try:
if payment < cost:
deficit = cost - payment
spendables = yield ledger.get_spendable_utxos(deficit, funding_accounts)
if not spendables:
raise ValueError('Not enough funds to cover this transaction.')
payment += sum(s.effective_amount for s in spendables)
tx.add_inputs(s.txi for s in spendables)
if payment > cost:
cost_of_change = (
tx.get_base_fee(ledger) +
cls.output_class.pay_pubkey_hash(COIN, NULL_HASH32).get_fee(ledger)
)
change = payment - cost
if change > cost_of_change:
change_address = yield change_account.change.get_or_create_usable_address()
change_hash160 = change_account.ledger.address_to_hash160(change_address)
change_amount = change - cost_of_change
change_output = cls.output_class.pay_pubkey_hash(change_amount, change_hash160)
change_output.is_change = True
tx.add_outputs([cls.output_class.pay_pubkey_hash(change_amount, change_hash160)])
yield tx.sign(funding_accounts)
except Exception as e:
log.exception('Failed to synchronize transaction:')
yield ledger.release_outputs(tx.outputs)
raise e
defer.returnValue(tx)
@staticmethod
def signature_hash_type(hash_type):
return hash_type
@defer.inlineCallbacks
def sign(self, funding_accounts: Iterable[BaseAccount]) -> defer.Deferred:
ledger = self.ensure_all_have_same_ledger(funding_accounts)
for i, txi in enumerate(self._inputs):
assert txi.script is not None
assert txi.txo_ref.txo is not None
txo_script = txi.txo_ref.txo.script
if txo_script.is_pay_pubkey_hash:
address = ledger.hash160_to_address(txo_script.values['pubkey_hash'])
private_key = yield ledger.get_private_key_for_address(address)
tx = self._serialize_for_signature(i)
txi.script.values['signature'] = \
private_key.sign(tx) + bytes((self.signature_hash_type(1),))
txi.script.values['pubkey'] = private_key.public_key.pubkey_bytes
txi.script.generate()
else:
raise NotImplementedError("Don't know how to spend this output.")
self._reset()