Annotate jwt.algorithms (#2532)

Cf. #1446

third_party/3/jwt/algorithms.pyi

@@ -1,3 +1,83 @@
-from typing import Any
+import sys
+from hashlib import _Hash
+from typing import Any, Set, Dict, Optional, ClassVar, Union, Generic, TypeVar
 
-class Algorithm(Any): ...  # type: ignore
+requires_cryptography = Set[str]
+
+def get_default_algorithms() -> Dict[str, Algorithm]: ...
+
+_K = TypeVar("_K")
+
+class Algorithm(Generic[_K]):
+    def prepare_key(self, key: _K) -> _K: ...
+    def sign(self, msg: bytes, key: _K) -> bytes: ...
+    def verify(self, msg: bytes, key: _K, sig: bytes) -> bool: ...
+    @staticmethod
+    def to_jwk(key_obj: Any) -> str: ...  # should be key_obj: _K, see python/mypy#1337
+    @staticmethod
+    def from_jwk(jwk: str) -> Any: ...  # should return _K, see python/mypy#1337
+
+
+class NoneAlgorithm(Algorithm[None]):
+    def prepare_key(self, key: Optional[str]) -> None: ...
+
+class _HashAlg:
+    def __call__(self, arg: Union[bytes, bytearray, memoryview] = ...) -> _Hash: ...
+
+if sys.version_info >= (3, 6):
+    _LoadsString = Union[str, bytes, bytearray]
+else:
+    _LoadsString = str
+
+class HMACAlgorithm(Algorithm[bytes]):
+    SHA256: ClassVar[_HashAlg]
+    SHA384: ClassVar[_HashAlg]
+    SHA512: ClassVar[_HashAlg]
+    hash_alg: _HashAlg
+    def __init__(self, _HashAlg) -> None: ...
+    def prepare_key(self, key: Union[str, bytes]) -> bytes: ...
+    @staticmethod
+    def to_jwk(key_obj: Union[str, bytes]) -> str: ...
+    @staticmethod
+    def from_jwk(jwk: _LoadsString) -> bytes: ...
+
+# Only defined if cryptography is installed. Types should be tightened when
+# cryptography gets type hints.
+# See https://github.com/python/typeshed/issues/2542
+class RSAAlgorithm(Algorithm):
+    SHA256: ClassVar[Any]
+    SHA384: ClassVar[Any]
+    SHA512: ClassVar[Any]
+    hash_alg: Any
+    def __init__(self, hash_alg: Any) -> None: ...
+    def prepare_key(self, key: Any) -> Any: ...
+    @staticmethod
+    def to_jwk(key_obj: Any) -> str: ...
+    @staticmethod
+    def from_jwk(jwk: _LoadsString) -> Any: ...
+    def sign(self, msg: bytes, key: Any) -> bytes: ...
+    def verify(self, msg: bytes, key: Any, sig: bytes) -> bool: ...
+
+# Only defined if cryptography is installed. Types should be tightened when
+# cryptography gets type hints.
+# See https://github.com/python/typeshed/issues/2542
+class ECAlgorithm(Algorithm):
+    SHA256: ClassVar[Any]
+    SHA384: ClassVar[Any]
+    SHA512: ClassVar[Any]
+    hash_alg: Any
+    def __init__(self, hash_alg: Any) -> None: ...
+    def prepare_key(self, key: Any) -> Any: ...
+    @staticmethod
+    def to_jwk(key_obj: Any) -> str: ...
+    @staticmethod
+    def from_jwk(jwk: _LoadsString) -> Any: ...
+    def sign(self, msg: bytes, key: Any) -> bytes: ...
+    def verify(self, msg: bytes, key: Any, sig: bytes) -> bool: ...
+
+# Only defined if cryptography is installed. Types should be tightened when
+# cryptography gets type hints.
+# See https://github.com/python/typeshed/issues/2542
+class RSAPSSAlgorithm(RSAAlgorithm):
+    def sign(self, msg: bytes, key: Any) -> bytes: ...
+    def verify(self, msg: bytes, key: Any, sig: bytes) -> bool: ...