forked from LBRYCommunity/lbry-sdk
363 lines
12 KiB
Python
363 lines
12 KiB
Python
import six
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import logging
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from typing import List, Iterable, Generator
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from binascii import hexlify
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from torba import baseledger
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from torba.basescript import BaseInputScript, BaseOutputScript
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from torba.coinselection import CoinSelector
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from torba.constants import COIN
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from torba.bcd_data_stream import BCDataStream
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from torba.hash import sha256
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from torba.account import Account
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from torba.util import ReadOnlyList
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log = logging.getLogger()
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NULL_HASH = b'\x00'*32
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class InputOutput(object):
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def __init__(self, txid):
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self._txid = txid # type: bytes
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self.transaction = None # type: BaseTransaction
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self.index = None # type: int
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@property
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def txid(self):
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if self._txid is None:
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self._txid = self.transaction.id
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return self._txid
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@property
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def size(self):
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""" Size of this input / output in bytes. """
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stream = BCDataStream()
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self.serialize_to(stream)
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return len(stream.get_bytes())
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def serialize_to(self, stream):
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raise NotImplemented
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class BaseInput(InputOutput):
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script_class = None
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NULL_SIGNATURE = b'\x00'*72
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NULL_PUBLIC_KEY = b'\x00'*33
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def __init__(self, output_or_txid_index, script, sequence=0xFFFFFFFF, txid=None):
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super(BaseInput, self).__init__(txid)
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if isinstance(output_or_txid_index, BaseOutput):
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self.output = output_or_txid_index # type: BaseOutput
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self.output_txid = self.output.transaction.id
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self.output_index = self.output.index
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else:
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self.output = None # type: BaseOutput
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self.output_txid, self.output_index = output_or_txid_index
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self.sequence = sequence
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self.is_coinbase = self.output_txid == NULL_HASH
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self.coinbase = script if self.is_coinbase else None
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self.script = script if not self.is_coinbase else None # type: BaseInputScript
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def link_output(self, output):
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assert self.output is None
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assert self.output_txid == output.transaction.id
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assert self.output_index == output.index
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self.output = output
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@classmethod
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def spend(cls, output):
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""" Create an input to spend the output."""
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assert output.script.is_pay_pubkey_hash, 'Attempting to spend unsupported output.'
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script = cls.script_class.redeem_pubkey_hash(cls.NULL_SIGNATURE, cls.NULL_PUBLIC_KEY)
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return cls(output, script)
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@property
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def amount(self):
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""" Amount this input adds to the transaction. """
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if self.output is None:
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raise ValueError('Cannot get input value without referenced output.')
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return self.output.amount
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@classmethod
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def deserialize_from(cls, stream):
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txid = stream.read(32)
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index = stream.read_uint32()
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script = stream.read_string()
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sequence = stream.read_uint32()
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return cls(
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(txid, index),
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cls.script_class(script) if not txid == NULL_HASH else script,
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sequence
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)
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def serialize_to(self, stream, alternate_script=None):
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stream.write(self.output_txid)
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stream.write_uint32(self.output_index)
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if alternate_script is not None:
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stream.write_string(alternate_script)
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else:
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if self.is_coinbase:
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stream.write_string(self.coinbase)
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else:
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stream.write_string(self.script.source)
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stream.write_uint32(self.sequence)
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class BaseOutputEffectiveAmountEstimator(object):
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__slots__ = 'coin', 'txi', 'txo', 'fee', 'effective_amount'
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def __init__(self, ledger, txo): # type: (baseledger.BaseLedger, BaseOutput) -> None
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self.txo = txo
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self.txi = ledger.transaction_class.input_class.spend(txo)
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self.fee = ledger.get_input_output_fee(self.txi)
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self.effective_amount = txo.amount - self.fee
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def __lt__(self, other):
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return self.effective_amount < other.effective_amount
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class BaseOutput(InputOutput):
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script_class = None
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estimator_class = BaseOutputEffectiveAmountEstimator
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def __init__(self, amount, script, txid=None):
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super(BaseOutput, self).__init__(txid)
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self.amount = amount # type: int
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self.script = script # type: BaseOutputScript
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def get_estimator(self, ledger):
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return self.estimator_class(ledger, self)
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@classmethod
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def pay_pubkey_hash(cls, amount, pubkey_hash):
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return cls(amount, cls.script_class.pay_pubkey_hash(pubkey_hash))
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@classmethod
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def deserialize_from(cls, stream):
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return cls(
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amount=stream.read_uint64(),
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script=cls.script_class(stream.read_string())
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)
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def serialize_to(self, stream):
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stream.write_uint64(self.amount)
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stream.write_string(self.script.source)
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class BaseTransaction:
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input_class = None
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output_class = None
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def __init__(self, raw=None, version=1, locktime=0):
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self._raw = raw
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self._hash = None
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self._id = None
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self.version = version # type: int
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self.locktime = locktime # type: int
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self._inputs = [] # type: List[BaseInput]
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self._outputs = [] # type: List[BaseOutput]
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if raw is not None:
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self._deserialize()
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@property
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def hex_id(self):
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return hexlify(self.id)
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@property
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def id(self):
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if self._id is None:
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self._id = self.hash[::-1]
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return self._id
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@property
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def hash(self):
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if self._hash is None:
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self._hash = sha256(sha256(self.raw))
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return self._hash
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@property
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def raw(self):
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if self._raw is None:
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self._raw = self._serialize()
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return self._raw
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def _reset(self):
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self._id = None
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self._hash = None
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self._raw = None
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@property
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def inputs(self): # type: () -> ReadOnlyList[BaseInput]
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return ReadOnlyList(self._inputs)
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@property
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def outputs(self): # type: () -> ReadOnlyList[BaseOutput]
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return ReadOnlyList(self._outputs)
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def _add(self, new_ios, existing_ios):
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for txio in new_ios:
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txio.transaction = self
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txio.index = len(existing_ios)
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existing_ios.append(txio)
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self._reset()
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return self
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def add_inputs(self, inputs):
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return self._add(inputs, self._inputs)
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def add_outputs(self, outputs):
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return self._add(outputs, self._outputs)
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@property
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def fee(self):
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""" Fee that will actually be paid."""
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return self.input_sum - self.output_sum
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@property
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def size(self):
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""" Size in bytes of the entire transaction. """
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return len(self.raw)
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@property
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def base_size(self):
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""" Size in bytes of transaction meta data and all outputs; without inputs. """
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return len(self._serialize(with_inputs=False))
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def _serialize(self, with_inputs=True):
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stream = BCDataStream()
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stream.write_uint32(self.version)
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if with_inputs:
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stream.write_compact_size(len(self._inputs))
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for txin in self._inputs:
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txin.serialize_to(stream)
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stream.write_compact_size(len(self._outputs))
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for txout in self._outputs:
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txout.serialize_to(stream)
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stream.write_uint32(self.locktime)
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return stream.get_bytes()
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def _serialize_for_signature(self, signing_input):
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stream = BCDataStream()
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stream.write_uint32(self.version)
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stream.write_compact_size(len(self._inputs))
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for i, txin in enumerate(self._inputs):
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if signing_input == i:
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txin.serialize_to(stream, txin.output.script.source)
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else:
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txin.serialize_to(stream, b'')
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stream.write_compact_size(len(self._outputs))
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for txout in self._outputs:
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txout.serialize_to(stream)
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stream.write_uint32(self.locktime)
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stream.write_uint32(1) # signature hash type: SIGHASH_ALL
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return stream.get_bytes()
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def _deserialize(self):
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if self._raw is not None:
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stream = BCDataStream(self._raw)
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self.version = stream.read_uint32()
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input_count = stream.read_compact_size()
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self.add_inputs([
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self.input_class.deserialize_from(stream) for _ in range(input_count)
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])
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output_count = stream.read_compact_size()
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self.add_outputs([
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self.output_class.deserialize_from(stream) for _ in range(output_count)
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])
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self.locktime = stream.read_uint32()
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@classmethod
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def get_effective_amount_estimators(cls, funding_accounts):
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# type: (Iterable[Account]) -> Generator[BaseOutputEffectiveAmountEstimator]
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for account in funding_accounts:
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for utxo in account.coin.ledger.get_unspent_outputs(account):
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yield utxo.get_estimator(account.coin)
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@classmethod
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def ensure_all_have_same_ledger(cls, funding_accounts, change_account=None):
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# type: (Iterable[Account], Account) -> baseledger.BaseLedger
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ledger = None
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for account in funding_accounts:
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if ledger is None:
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ledger = account.coin.ledger
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if ledger != account.coin.ledger:
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raise ValueError(
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'All funding accounts used to create a transaction must be on the same ledger.'
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)
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if change_account is not None and change_account.coin.ledger != ledger:
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raise ValueError('Change account must use same ledger as funding accounts.')
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return ledger
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@classmethod
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def pay(cls, outputs, funding_accounts, change_account):
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""" Efficiently spend utxos from funding_accounts to cover the new outputs. """
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tx = cls().add_outputs(outputs)
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ledger = cls.ensure_all_have_same_ledger(funding_accounts, change_account)
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amount = ledger.get_transaction_base_fee(tx)
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selector = CoinSelector(
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list(cls.get_effective_amount_estimators(funding_accounts)),
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amount,
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ledger.get_input_output_fee(
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cls.output_class.pay_pubkey_hash(COIN, NULL_HASH)
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)
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)
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spendables = selector.select()
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if not spendables:
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raise ValueError('Not enough funds to cover this transaction.')
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spent_sum = sum(s.effective_amount for s in spendables)
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if spent_sum > amount:
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change_address = change_account.get_least_used_change_address()
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change_hash160 = change_account.coin.address_to_hash160(change_address)
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change_amount = spent_sum - amount
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tx.add_outputs([cls.output_class.pay_pubkey_hash(change_amount, change_hash160)])
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tx.add_inputs([s.txi for s in spendables])
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tx.sign(funding_accounts)
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return tx
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@classmethod
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def liquidate(cls, assets, funding_accounts, change_account):
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""" Spend assets (utxos) supplementing with funding_accounts if fee is higher than asset value. """
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def sign(self, funding_accounts): # type: (Iterable[Account]) -> BaseTransaction
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ledger = self.ensure_all_have_same_ledger(funding_accounts)
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for i, txi in enumerate(self._inputs):
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txo_script = txi.output.script
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if txo_script.is_pay_pubkey_hash:
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address = ledger.coin_class.hash160_to_address(txo_script.values['pubkey_hash'])
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account = ledger.accounts.get_account_for_address(address)
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private_key = account.get_private_key_for_address(address)
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tx = self._serialize_for_signature(i)
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txi.script.values['signature'] = private_key.sign(tx)+six.int2byte(1)
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txi.script.values['pubkey'] = private_key.public_key.pubkey_bytes
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txi.script.generate()
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else:
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raise NotImplementedError("Don't know how to spend this output.")
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self._reset()
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return self
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def sort(self):
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# See https://github.com/kristovatlas/rfc/blob/master/bips/bip-li01.mediawiki
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self._inputs.sort(key=lambda i: (i['prevout_hash'], i['prevout_n']))
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self._outputs.sort(key=lambda o: (o[2], pay_script(o[0], o[1])))
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@property
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def input_sum(self):
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return sum(i.amount for i in self._inputs)
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@property
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def output_sum(self):
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return sum(o.amount for o in self._outputs)
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