from decimal import Decimal
from typing import Optional, Union
from .. import xdr as stellar_xdr
from ..asset import Asset
from ..liquidity_pool_asset import LiquidityPoolAsset
from ..muxed_account import MuxedAccount
from ..utils import raise_if_not_valid_amount
from .operation import Operation
__all__ = ["ChangeTrust"]
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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://developers.stellar.org/docs/glossary/assets/>`_.
Threshold: Medium
See `Change Trust <https://developers.stellar.org/docs/start/list-of-operations/#change-trust>`_ for more information.
: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 for the operation. Defaults to the transaction's source account.
"""
_DEFAULT_LIMIT = "922337203685.4775807"
_XDR_OPERATION_TYPE: stellar_xdr.OperationType = (
stellar_xdr.OperationType.CHANGE_TRUST
)
def __init__(
self,
asset: Union[Asset, LiquidityPoolAsset],
limit: Union[str, Decimal, None] = None, # _DEFAULT_LIMIT default
source: Optional[Union[MuxedAccount, str]] = None,
) -> None:
super().__init__(source)
self.asset = asset
if limit is None:
self.limit: str = self._DEFAULT_LIMIT
else:
limit = str(limit)
self.limit = limit
raise_if_not_valid_amount(self.limit, "limit")
def _to_operation_body(self) -> stellar_xdr.OperationBody:
line = self.asset.to_change_trust_asset_xdr_object()
limit = stellar_xdr.Int64(Operation.to_xdr_amount(self.limit))
change_trust_op = stellar_xdr.ChangeTrustOp(line, limit)
body = stellar_xdr.OperationBody(
type=self._XDR_OPERATION_TYPE, change_trust_op=change_trust_op
)
return body
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@classmethod
def from_xdr_object(cls, xdr_object: stellar_xdr.Operation) -> "ChangeTrust":
"""Creates a :class:`ChangeTrust` object from an XDR Operation
object.
"""
source = Operation.get_source_from_xdr_obj(xdr_object)
assert xdr_object.body.change_trust_op is not None
if (
xdr_object.body.change_trust_op.line.type
== stellar_xdr.AssetType.ASSET_TYPE_POOL_SHARE
):
line: Union[Asset, LiquidityPoolAsset] = LiquidityPoolAsset.from_xdr_object(
xdr_object.body.change_trust_op.line
)
else:
line = Asset.from_xdr_object(xdr_object.body.change_trust_op.line)
limit = Operation.from_xdr_amount(xdr_object.body.change_trust_op.limit.int64)
op = cls(source=source, asset=line, limit=limit)
return op
def __str__(self):
return f"<ChangeTrust [asset={self.asset}, limit={self.limit}, source={self.source}]>"