from decimal import Decimal
from typing import Union
from .operation import Operation
from .utils import check_amount
from ..asset import Asset
from ..xdr import Xdr
[docs]class ChangeTrust(Operation):
"""The :class:`ChangeTrust` object, which represents a ChangeTrust
operation on Stellar's network.
Creates, updates, or deletes a trustline. For more on trustlines, please
refer to the `assets documentation
<https://www.stellar.org/developers/guides/concepts/assets.html>_`.
Threshold: Medium
:param asset: The asset for the trust line.
:param limit: The limit for the asset, defaults to max int64(922337203685.4775807).
If the limit is set to "0" it deletes the trustline.
:param source: The source account (defaults to transaction source).
"""
_DEFAULT_LIMIT = "922337203685.4775807"
def __init__(
self, asset: Asset, limit: Union[str, Decimal] = None, source: str = None,
) -> None:
super().__init__(source)
self.asset: Asset = asset
if (
limit is None
): # We don't need this if the user can send the value with correct type.
self.limit: Union[str, Decimal] = self._DEFAULT_LIMIT
else:
check_amount(limit)
self.limit = limit
@classmethod
def type_code(cls) -> int:
return Xdr.const.CHANGE_TRUST
def _to_operation_body(self) -> Xdr.nullclass:
line = self.asset.to_xdr_object()
limit = Operation.to_xdr_amount(self.limit)
change_trust_op = Xdr.types.ChangeTrustOp(line, limit)
body = Xdr.nullclass()
body.type = Xdr.const.CHANGE_TRUST
body.changeTrustOp = change_trust_op
return body
[docs] @classmethod
def from_xdr_object(
cls, operation_xdr_object: Xdr.types.Operation
) -> "ChangeTrust":
"""Creates a :class:`ChangeTrust` object from an XDR Operation
object.
"""
source = Operation.get_source_from_xdr_obj(operation_xdr_object)
line = Asset.from_xdr_object(operation_xdr_object.body.changeTrustOp.line)
limit = Operation.from_xdr_amount(operation_xdr_object.body.changeTrustOp.limit)
op = cls(source=source, asset=line, limit=limit)
op._source_muxed = Operation.get_source_muxed_from_xdr_obj(operation_xdr_object)
return op