mercurial/typelib.py

rust-inner-revlog: cache the compressor

The `compress` function is unlikely to be used in highly contended situations,
and creating a compressor has some overhead, on top of losing out on some
potential advantages of longer-running optimizations from the compressor.

# typelib.py - type hint aliases and support
#
# Copyright 2022 Matt Harbison <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import annotations

import typing

from typing import (
    Callable,
)

# Note: this is slightly different from pycompat.TYPE_CHECKING, as using
# pycompat causes the BinaryIO_Proxy type to be resolved to ``object`` when
# used as the base class during a pytype run.
TYPE_CHECKING = typing.TYPE_CHECKING


# The BinaryIO class provides empty methods, which at runtime means that
# ``__getattr__`` on the proxy classes won't get called for the methods that
# should delegate to the internal object.  So to avoid runtime changes because
# of the required typing inheritance, just use BinaryIO when typechecking, and
# ``object`` otherwise.
if TYPE_CHECKING:
    from typing import (
        BinaryIO,
        Union,
    )

    from . import (
        node,
        posix,
        util,
        windows,
    )

    BinaryIO_Proxy = BinaryIO
    CacheStat = Union[
        posix.cachestat,
        windows.cachestat,
        util.uncacheable_cachestat,
    ]
    NodeConstants = node.sha1nodeconstants
else:
    from typing import Any

    BinaryIO_Proxy = object
    CacheStat = Any
    NodeConstants = Any

# scmutil.getuipathfn() related callback.
UiPathFn = Callable[[bytes], bytes]