mesonbuild/_typing.py

# SPDX-License-Identifer: Apache-2.0
# Copyright 2020 The Meson development team
# Copyright © 2020-2021 Intel Corporation

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Meson specific typing helpers.

Holds typing helper classes, such as the ImmutableProtocol classes
"""

__all__ = [
    'Protocol',
    'ImmutableListProtocol'
]

import typing

# We can change this to typing when we require python 3.8
from typing_extensions import Protocol


T = typing.TypeVar('T')


class StringProtocol(Protocol):
    def __str__(self) -> str: ...

class SizedStringProtocol(Protocol, StringProtocol, typing.Sized):
    pass

class ImmutableListProtocol(Protocol[T]):

    """A protocol used in cases where a list is returned, but should not be
    mutated.

    This provides all of the methods of a Sequence, as well as copy(). copy()
    returns a list, which allows mutation as it's a copy and that's (hopefully)
    safe.

    One particular case this is important is for cached values, since python is
    a pass-by-reference language.
    """

    def __iter__(self) -> typing.Iterator[T]: ...

    @typing.overload
    def __getitem__(self, index: int) -> T: ...
    @typing.overload
    def __getitem__(self, index: slice) -> typing.List[T]: ...

    def __contains__(self, item: T) -> bool: ...

    def __reversed__(self) -> typing.Iterator[T]: ...

    def __len__(self) -> int: ...

    def __add__(self, other: typing.List[T]) -> typing.List[T]: ...

    def __eq__(self, other: typing.Any) -> bool: ...
    def __ne__(self, other: typing.Any) -> bool: ...
    def __le__(self, other: typing.Any) -> bool: ...
    def __lt__(self, other: typing.Any) -> bool: ...
    def __gt__(self, other: typing.Any) -> bool: ...
    def __ge__(self, other: typing.Any) -> bool: ...

    def count(self, item: T) -> int: ...

    def index(self, item: T) -> int: ...

    def copy(self) -> typing.List[T]: ...