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"""Asset data encoding and decoding utilities."""
from mypy_extensions import TypedDict
import eth_abi
from zero_ex.dev_utils import abi_utils
from zero_ex.dev_utils.type_assertions import assert_is_string, assert_is_int
ERC20_ASSET_DATA_BYTE_LENGTH = 36
ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH = 53
SELECTOR_LENGTH = 10
class ERC20AssetData(TypedDict):
"""Object interface to ERC20 asset data."""
asset_proxy_id: str
token_address: str
class ERC721AssetData(TypedDict):
"""Object interface to ERC721 asset data."""
asset_proxy_id: str
token_address: str
token_id: int
def encode_erc20_asset_data(token_address: str) -> str:
"""Encode an ERC20 token address into an asset data string.
:param token_address: the ERC20 token's contract address.
:rtype: hex encoded asset data string, usable in the makerAssetData or
takerAssetData fields in a 0x order.
>>> encode_erc20_asset_data('0x1dc4c1cefef38a777b15aa20260a54e584b16c48')
'0xf47261b00000000000000000000000001dc4c1cefef38a777b15aa20260a54e584b16c48'
"""
assert_is_string(token_address, "token_address")
return (
"0x"
+ abi_utils.simple_encode("ERC20Token(address)", token_address).hex()
)
def decode_erc20_asset_data(asset_data: str) -> ERC20AssetData:
"""Decode an ERC20 asset data hex string.
:param asset_data: String produced by prior call to encode_erc20_asset_data()
>>> decode_erc20_asset_data("0xf47261b00000000000000000000000001dc4c1cefef38a777b15aa20260a54e584b16c48")
{'asset_proxy_id': '0xf47261b0', 'token_address': '0x1dc4c1cefef38a777b15aa20260a54e584b16c48'}
""" # noqa: E501 (line too long)
assert_is_string(asset_data, "asset_data")
if len(asset_data) < ERC20_ASSET_DATA_BYTE_LENGTH:
raise ValueError(
"Could not decode ERC20 Proxy Data. Expected length of encoded"
+ f" data to be at least {str(ERC20_ASSET_DATA_BYTE_LENGTH)}."
+ f" Got {str(len(asset_data))}."
)
asset_proxy_id: str = asset_data[0:SELECTOR_LENGTH]
if asset_proxy_id != abi_utils.method_id("ERC20Token", ["address"]):
raise ValueError(
"Could not decode ERC20 Proxy Data. Expected Asset Proxy Id to be"
+ f" ERC20 ({abi_utils.method_id('ERC20Token', ['address'])})"
+ f" but got {asset_proxy_id}."
)
# workaround for https://github.com/PyCQA/pylint/issues/1498
# pylint: disable=unsubscriptable-object
token_address = eth_abi.decode_abi(
["address"], bytes.fromhex(asset_data[SELECTOR_LENGTH:])
)[0]
return {"asset_proxy_id": asset_proxy_id, "token_address": token_address}
def encode_erc721_asset_data(token_address: str, token_id: int) -> str:
"""Encode an ERC721 asset data hex string.
:param token_address: the ERC721 token's contract address.
:param token_id: the identifier of the asset's instance of the token.
:rtype: hex encoded asset data string, usable in the makerAssetData or
takerAssetData fields in a 0x order.
>>> encode_erc721_asset_data('0x1dc4c1cefef38a777b15aa20260a54e584b16c48', 1)
'0x025717920000000000000000000000001dc4c1cefef38a777b15aa20260a54e584b16c480000000000000000000000000000000000000000000000000000000000000001'
""" # noqa: E501 (line too long)
assert_is_string(token_address, "token_address")
assert_is_int(token_id, "token_id")
return (
"0x"
+ abi_utils.simple_encode(
"ERC721Token(address,uint256)", token_address, token_id
).hex()
)
def decode_erc721_asset_data(asset_data: str) -> ERC721AssetData:
"""Decode an ERC721 asset data hex string.
>>> decode_erc721_asset_data('0x025717920000000000000000000000001dc4c1cefef38a777b15aa20260a54e584b16c480000000000000000000000000000000000000000000000000000000000000001')
{'asset_proxy_id': '0x02571792', 'token_address': '0x1dc4c1cefef38a777b15aa20260a54e584b16c48', 'token_id': 1}
""" # noqa: E501 (line too long)
assert_is_string(asset_data, "asset_data")
if len(asset_data) < ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH:
raise ValueError(
"Could not decode ERC721 Asset Data. Expected length of encoded"
+ f"data to be at least {ERC721_ASSET_DATA_MINIMUM_BYTE_LENGTH}. "
+ f"Got {len(asset_data)}."
)
asset_proxy_id: str = asset_data[0:SELECTOR_LENGTH]
if asset_proxy_id != abi_utils.method_id(
"ERC721Token", ["address", "uint256"]
):
raise ValueError(
"Could not decode ERC721 Asset Data. Expected Asset Proxy Id to be"
+ f" ERC721 ("
+ f"{abi_utils.method_id('ERC721Token', ['address', 'uint256'])}"
+ f"), but got {asset_proxy_id}"
)
(token_address, token_id) = eth_abi.decode_abi(
["address", "uint256"], bytes.fromhex(asset_data[SELECTOR_LENGTH:])
)
return {
"asset_proxy_id": asset_proxy_id,
"token_address": token_address,
"token_id": token_id,
}
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