annotate hgext/fsmonitor/pywatchman/encoding.py @ 51863:f4733654f144

typing: add `from __future__ import annotations` to most files

Now that py36 is no longer supported, we can postpone annotation evaluation.
This means that the quoting is usually optional (for things imported under the
guard of `if typing.TYPE_CHECKING:` to avoid circular imports), and there's less
overhead on startup[1].

There may be some missing here.  I backed out 6000f5b25c9b (which removed the
`from __future__ import ...` that was supporting py2), reverted the changes in
`contrib/`, `doc/`, and `tests/`, and then ran:

    $ hg status -n --change . | \
        xargs sed -i -e 's/from __future__ import .*$/from __future__ import annotations/'

There were some minor tweaks needed when reviewing (mostly making the spacing
around the import consistent, and `mercurial/testing/__init__.py` had a
multiline import that wasn't fully rewritten.

[1] https://docs.python.org/3/whatsnew/3.7.html#pep-563-postponed-evaluation-of-annotations

# Copyright 2016-present Facebook, Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#  * Redistributions of source code must retain the above copyright notice,
#    this list of conditions and the following disclaimer.
#
#  * Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
#
#  * Neither the name Facebook nor the names of its contributors may be used to
#    endorse or promote products derived from this software without specific
#    prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

from __future__ import annotations

import sys

from . import compat


"""Module to deal with filename encoding on the local system, as returned by
Watchman."""


if compat.PYTHON3:
    default_local_errors = "surrogateescape"

    def get_local_encoding():
        if sys.platform == "win32":
            # Watchman always returns UTF-8 encoded strings on Windows.
            return "utf-8"
        # On the Python 3 versions we support, sys.getfilesystemencoding never
        # returns None.
        return sys.getfilesystemencoding()

else:
    # Python 2 doesn't support surrogateescape, so use 'strict' by
    # default. Users can register a custom surrogateescape error handler and use
    # that if they so desire.
    default_local_errors = "strict"

    def get_local_encoding():
        if sys.platform == "win32":
            # Watchman always returns UTF-8 encoded strings on Windows.
            return "utf-8"
        fsencoding = sys.getfilesystemencoding()
        if fsencoding is None:
            # This is very unlikely to happen, but if it does, just use UTF-8
            fsencoding = "utf-8"
        return fsencoding


def encode_local(s):
    return s.encode(get_local_encoding(), default_local_errors)


def decode_local(bs):
    return bs.decode(get_local_encoding(), default_local_errors)