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 @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' def __init__(self, amount: int, script: BaseOutputScript, tx_ref: TXRef = None, position: int = None) -> None: super().__init__(tx_ref, position) self.amount = amount self.script = script self.is_change = None @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=1, locktime=0, height=None) -> None: self._raw = raw self.ref = TXRefMutable(self) self.version = version # type: int self.locktime = locktime # type: int self._inputs = [] # type: List[BaseInput] self._outputs = [] # type: List[BaseOutput] self.height = height 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): # type: () -> ReadOnlyList[BaseInput] return ReadOnlyList(self._inputs) @property def outputs(self): # type: () -> 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) @property def output_sum(self): return sum(o.amount for o in self.outputs) @property def fee(self): return self.input_sum - self.output_sum def get_base_fee(self, ledger): """ Fee for base tx excluding inputs and outputs. """ return self.base_size * ledger.fee_per_byte def get_effective_input_sum(self, ledger): """ 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): """ 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()