view hgext/fsmonitor/pywatchman/encoding.py @ 51901: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

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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)