diff options
Diffstat (limited to 'python-packages/order_utils/src/zero_ex/dev_utils/abi_utils.py')
-rw-r--r-- | python-packages/order_utils/src/zero_ex/dev_utils/abi_utils.py | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/python-packages/order_utils/src/zero_ex/dev_utils/abi_utils.py b/python-packages/order_utils/src/zero_ex/dev_utils/abi_utils.py new file mode 100644 index 000000000..71b6128ca --- /dev/null +++ b/python-packages/order_utils/src/zero_ex/dev_utils/abi_utils.py @@ -0,0 +1,102 @@ +"""Ethereum ABI utilities. + +Builds on the eth-abi package, adding some convenience methods like those found +in npmjs.com/package/ethereumjs-abi. Ideally, all of this code should be +pushed upstream into eth-abi. +""" + +import re +from typing import Any, List + +from mypy_extensions import TypedDict + +from eth_abi import encode_abi +from web3 import Web3 + +from .type_assertions import assert_is_string, assert_is_list + + +class MethodSignature(TypedDict, total=False): + """Object interface to an ABI method signature.""" + + method: str + args: List[str] + + +def parse_signature(signature: str) -> MethodSignature: + """Parse a method signature into its constituent parts. + + >>> parse_signature("ERC20Token(address)") + {'method': 'ERC20Token', 'args': ['address']} + """ + assert_is_string(signature, "signature") + + matches = re.match(r"^(\w+)\((.+)\)$", signature) + if matches is None: + raise ValueError(f"Invalid method signature {signature}") + return {"method": matches[1], "args": matches[2].split(",")} + + +def elementary_name(name: str) -> str: + """Convert from short to canonical names; barely implemented. + + Modeled after ethereumjs-abi's ABI.elementaryName(), but only implemented + to support our particular use case and a few other simple ones. + + >>> elementary_name("address") + 'address' + >>> elementary_name("uint") + 'uint256' + """ + assert_is_string(name, "name") + + return { + "int": "int256", + "uint": "uint256", + "fixed": "fixed128x128", + "ufixed": "ufixed128x128", + }.get(name, name) + + +def event_id(name: str, types: List[str]) -> str: + """Return the Keccak-256 hash of the given method. + + >>> event_id("ERC20Token", ["address"]) + '0xf47261b06eedbfce68afd46d0f3c27c60b03faad319eaf33103611cf8f6456ad' + """ + assert_is_string(name, "name") + assert_is_list(types, "types") + + signature = f"{name}({','.join(list(map(elementary_name, types)))})" + return Web3.sha3(text=signature).hex() + + +def method_id(name: str, types: List[str]) -> str: + """Return the 4-byte method identifier. + + >>> method_id("ERC20Token", ["address"]) + '0xf47261b0' + """ + assert_is_string(name, "name") + assert_is_list(types, "types") + + return event_id(name, types)[0:10] + + +def simple_encode(method: str, *args: Any) -> bytes: + # docstring considered all one line by pylint: disable=line-too-long + r"""Encode a method ABI. + + >>> simple_encode("ERC20Token(address)", "0x1dc4c1cefef38a777b15aa20260a54e584b16c48") + b'\xf4ra\xb0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x1d\xc4\xc1\xce\xfe\xf3\x8aw{\x15\xaa &\nT\xe5\x84\xb1lH' + """ # noqa: E501 (line too long) + assert_is_string(method, "method") + + signature: MethodSignature = parse_signature(method) + + return bytes.fromhex( + ( + method_id(signature["method"], signature["args"]) + + encode_abi(signature["args"], args).hex() + )[2:] + ) |