542 lines
18 KiB
Python
542 lines
18 KiB
Python
import logging
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import typing
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from typing import List, Iterable, Optional
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from binascii import hexlify
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from torba.client.basescript import BaseInputScript, BaseOutputScript
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from torba.client.baseaccount import BaseAccount
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from torba.client.constants import COIN, NULL_HASH32
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from torba.client.bcd_data_stream import BCDataStream
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from torba.client.hash import sha256, TXRef, TXRefImmutable
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from torba.client.util import ReadOnlyList
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from torba.client.errors import InsufficientFundsError
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if typing.TYPE_CHECKING:
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from torba.client import baseledger
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log = logging.getLogger()
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class TXRefMutable(TXRef):
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__slots__ = ('tx',)
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def __init__(self, tx: 'BaseTransaction') -> None:
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super().__init__()
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self.tx = tx
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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 = hexlify(self.hash[::-1]).decode()
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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.tx.raw))
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return self._hash
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@property
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def height(self):
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return self.tx.height
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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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class TXORef:
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__slots__ = 'tx_ref', 'position'
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def __init__(self, tx_ref: TXRef, position: int) -> None:
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self.tx_ref = tx_ref
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self.position = position
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@property
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def id(self):
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return '{}:{}'.format(self.tx_ref.id, self.position)
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@property
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def hash(self):
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return self.tx_ref.hash + BCDataStream.uint32.pack(self.position)
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@property
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def is_null(self):
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return self.tx_ref.is_null
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@property
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def txo(self) -> Optional['BaseOutput']:
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return None
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class TXORefResolvable(TXORef):
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__slots__ = ('_txo',)
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def __init__(self, txo: 'BaseOutput') -> None:
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assert txo.tx_ref is not None
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assert txo.position is not None
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super().__init__(txo.tx_ref, txo.position)
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self._txo = txo
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@property
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def txo(self):
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return self._txo
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class InputOutput:
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__slots__ = 'tx_ref', 'position'
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def __init__(self, tx_ref: TXRef = None, position: int = None) -> None:
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self.tx_ref = tx_ref
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self.position = position
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@property
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def size(self) -> int:
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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 get_fee(self, ledger):
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return self.size * ledger.fee_per_byte
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def serialize_to(self, stream, alternate_script=None):
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raise NotImplementedError
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class BaseInput(InputOutput):
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script_class = BaseInputScript
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NULL_SIGNATURE = b'\x00'*72
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NULL_PUBLIC_KEY = b'\x00'*33
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__slots__ = 'txo_ref', 'sequence', 'coinbase', 'script'
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def __init__(self, txo_ref: TXORef, script: BaseInputScript, sequence: int = 0xFFFFFFFF,
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tx_ref: TXRef = None, position: int = None) -> None:
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super().__init__(tx_ref, position)
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self.txo_ref = txo_ref
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self.sequence = sequence
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self.coinbase = script if txo_ref.is_null else None
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self.script = script if not txo_ref.is_null else None
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@property
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def is_coinbase(self):
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return self.coinbase is not None
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@classmethod
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def spend(cls, txo: 'BaseOutput') -> 'BaseInput':
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""" Create an input to spend the output."""
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assert txo.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(txo.ref, script)
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@property
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def amount(self) -> int:
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""" Amount this input adds to the transaction. """
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if self.txo_ref.txo is None:
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raise ValueError('Cannot resolve output to get amount.')
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return self.txo_ref.txo.amount
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@property
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def is_my_account(self) -> Optional[bool]:
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""" True if the output this input spends is yours. """
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if self.txo_ref.txo is None:
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return False
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return self.txo_ref.txo.is_my_account
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@classmethod
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def deserialize_from(cls, stream):
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tx_ref = TXRefImmutable.from_hash(stream.read(32), -1)
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position = 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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TXORef(tx_ref, position),
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cls.script_class(script) if not tx_ref.is_null 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.txo_ref.tx_ref.hash)
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stream.write_uint32(self.txo_ref.position)
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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:
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__slots__ = 'txo', 'txi', 'fee', 'effective_amount'
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def __init__(self, ledger: 'baseledger.BaseLedger', txo: '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: int = self.txi.get_fee(ledger)
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self.effective_amount: int = 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 = BaseOutputScript
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estimator_class = BaseOutputEffectiveAmountEstimator
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__slots__ = 'amount', 'script', 'is_change', 'is_my_account'
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def __init__(self, amount: int, script: BaseOutputScript,
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tx_ref: TXRef = None, position: int = None,
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is_change: Optional[bool] = None, is_my_account: Optional[bool] = None
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) -> None:
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super().__init__(tx_ref, position)
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self.amount = amount
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self.script = script
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self.is_change = is_change
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self.is_my_account = is_my_account
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def update_annotations(self, annotated):
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if annotated is None:
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self.is_change = False
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self.is_my_account = False
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else:
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self.is_change = annotated.is_change
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self.is_my_account = annotated.is_my_account
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@property
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def ref(self):
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return TXORefResolvable(self)
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@property
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def id(self):
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return self.ref.id
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@property
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def pubkey_hash(self):
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return self.script.values['pubkey_hash']
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def get_address(self, ledger):
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return ledger.hash160_to_address(self.pubkey_hash)
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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, alternate_script=None):
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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 = BaseInput
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output_class = BaseOutput
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def __init__(self, raw=None, version: int = 1, locktime: int = 0, is_verified: bool = False,
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height: int = -2, position: int = -1) -> None:
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self._raw = raw
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self.ref = TXRefMutable(self)
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self.version = version
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self.locktime = locktime
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self._inputs: List[BaseInput] = []
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self._outputs: List[BaseOutput] = []
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self.is_verified = is_verified
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# Height Progression
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# -2: not broadcast
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# -1: in mempool but has unconfirmed inputs
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# 0: in mempool and all inputs confirmed
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# +num: confirmed in a specific block (height)
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self.height = height
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self.position = position
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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 is_broadcast(self):
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return self.height > -2
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@property
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def is_mempool(self):
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return self.height in (-1, 0)
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@property
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def is_confirmed(self):
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return self.height > 0
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@property
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def id(self):
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return self.ref.id
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@property
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def hash(self):
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return self.ref.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._raw = None
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self.ref.reset()
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@property
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def inputs(self) -> ReadOnlyList[BaseInput]:
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return ReadOnlyList(self._inputs)
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@property
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def outputs(self) -> ReadOnlyList[BaseOutput]:
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return ReadOnlyList(self._outputs)
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def _add(self, new_ios: Iterable[InputOutput], existing_ios: List) -> 'BaseTransaction':
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for txio in new_ios:
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txio.tx_ref = self.ref
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txio.position = 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: Iterable[BaseInput]) -> 'BaseTransaction':
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return self._add(inputs, self._inputs)
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def add_outputs(self, outputs: Iterable[BaseOutput]) -> 'BaseTransaction':
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return self._add(outputs, self._outputs)
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@property
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def size(self) -> int:
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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) -> int:
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""" Size of transaction without inputs or outputs in bytes. """
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return (
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self.size
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- sum(txi.size for txi in self._inputs)
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- sum(txo.size for txo in self._outputs)
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)
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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 if i.txo_ref.txo is not None)
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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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@property
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def net_account_balance(self) -> int:
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balance = 0
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for txi in self.inputs:
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if txi.txo_ref.txo is None:
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continue
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if txi.is_my_account is None:
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raise ValueError(
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"Cannot access net_account_balance if inputs/outputs do not "
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"have is_my_account set properly."
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)
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if txi.is_my_account:
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balance -= txi.amount
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for txo in self.outputs:
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if txo.is_my_account is None:
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raise ValueError(
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"Cannot access net_account_balance if inputs/outputs do not "
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"have is_my_account set properly."
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)
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if txo.is_my_account:
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balance += txo.amount
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return balance
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@property
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def fee(self) -> int:
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return self.input_sum - self.output_sum
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def get_base_fee(self, ledger) -> int:
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""" Fee for base tx excluding inputs and outputs. """
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return self.base_size * ledger.fee_per_byte
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def get_effective_input_sum(self, ledger) -> int:
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""" Sum of input values *minus* the cost involved to spend them. """
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return sum(txi.amount - txi.get_fee(ledger) for txi in self._inputs)
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def get_total_output_sum(self, ledger) -> int:
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""" Sum of output values *plus* the cost involved to spend them. """
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return sum(txo.amount + txo.get_fee(ledger) for txo in self._outputs)
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def _serialize(self, with_inputs: bool = True) -> bytes:
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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: int) -> bytes:
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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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assert txin.txo_ref.txo is not None
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txin.serialize_to(stream, txin.txo_ref.txo.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(self.signature_hash_type(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 ensure_all_have_same_ledger(cls, funding_accounts: Iterable[BaseAccount],
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change_account: BaseAccount = None) -> '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.ledger
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if ledger != account.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.ledger != ledger:
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raise ValueError('Change account must use same ledger as funding accounts.')
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if ledger is None:
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raise ValueError('No ledger found.')
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return ledger
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@classmethod
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async def create(cls, inputs: Iterable[BaseInput], outputs: Iterable[BaseOutput],
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funding_accounts: Iterable[BaseAccount], change_account: BaseAccount,
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sign: bool = True):
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""" Find optimal set of inputs when only outputs are provided; add change
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outputs if only inputs are provided or if inputs are greater than outputs. """
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tx = cls() \
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.add_inputs(inputs) \
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.add_outputs(outputs)
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ledger = cls.ensure_all_have_same_ledger(funding_accounts, change_account)
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# value of the outputs plus associated fees
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cost = (
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tx.get_base_fee(ledger) +
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tx.get_total_output_sum(ledger)
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)
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# value of the inputs less the cost to spend those inputs
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payment = tx.get_effective_input_sum(ledger)
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try:
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for _ in range(5):
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if payment < cost:
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deficit = cost - payment
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spendables = await ledger.get_spendable_utxos(deficit, funding_accounts)
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if not spendables:
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raise InsufficientFundsError('Not enough funds to cover this transaction.')
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payment += sum(s.effective_amount for s in spendables)
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tx.add_inputs(s.txi for s in spendables)
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cost_of_change = (
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tx.get_base_fee(ledger) +
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cls.output_class.pay_pubkey_hash(COIN, NULL_HASH32).get_fee(ledger)
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)
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if payment > cost:
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change = payment - cost
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if change > cost_of_change:
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change_address = await change_account.change.get_or_create_usable_address()
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change_hash160 = change_account.ledger.address_to_hash160(change_address)
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change_amount = change - cost_of_change
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change_output = cls.output_class.pay_pubkey_hash(change_amount, change_hash160)
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change_output.is_change = True
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tx.add_outputs([cls.output_class.pay_pubkey_hash(change_amount, change_hash160)])
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if tx._outputs:
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break
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else:
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# this condition and the outer range(5) loop cover an edge case
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# whereby a single input is just enough to cover the fee and
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# has some change left over, but the change left over is less
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# than the cost_of_change: thus the input is completely
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# consumed and no output is added, which is an invalid tx.
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# to be able to spend this input we must increase the cost
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# of the TX and run through the balance algorithm a second time
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# adding an extra input and change output, making tx valid.
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# we do this 5 times in case the other UTXOs added are also
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# less than the fee, after 5 attempts we give up and go home
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cost += cost_of_change + 1
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if sign:
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await tx.sign(funding_accounts)
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except Exception as e:
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log.exception('Failed to create transaction:')
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await ledger.release_tx(tx)
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raise e
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return tx
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@staticmethod
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def signature_hash_type(hash_type):
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return hash_type
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async def sign(self, funding_accounts: Iterable[BaseAccount]):
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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 = await 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()
|