view mercurial/scmwindows.py @ 52167:7346f93be7a4

revlog: add the glue to use the Rust `InnerRevlog` from Python

The performance of this has been looked at for quite some time, and some
workflows are actually quite a bit faster than with the Python + C code.

However, we are still (up to 20%) slower in some crucial places like cloning
certain repos, log, cat, which makes this an incomplete rewrite. This is
mostly due to the high amount of overhead in Python <-> Rust FFI, especially
around the VFS code. A future patch series will rewrite the VFS code in
pure Rust, which should hopefully get us up to par with current perfomance,
if not better in all important cases.

This is a "save state" of sorts, as this is a ton of code, and I don't want
to pile up even more things in a single review.

Continuing to try to match the current performance will take an extremely
long time, if it's not impossible, without the aforementioned VFS work.

from __future__ import annotations

import os
import winreg  # pytype: disable=import-error

from typing import (
    List,
    TYPE_CHECKING,
    Tuple,
)

from . import (
    encoding,
    pycompat,
    util,
    win32,
)

if TYPE_CHECKING:
    from . import ui as uimod

# MS-DOS 'more' is the only pager available by default on Windows.
fallbackpager = b'more'


def systemrcpath() -> List[bytes]:
    '''return default os-specific hgrc search path'''
    rcpath = []
    filename = win32.executablepath()
    # Use mercurial.ini found in directory with hg.exe
    progrc = os.path.join(os.path.dirname(filename), b'mercurial.ini')
    rcpath.append(progrc)

    def _processdir(progrcd: bytes) -> None:
        if os.path.isdir(progrcd):
            for f, kind in sorted(util.listdir(progrcd)):
                if f.endswith(b'.rc'):
                    rcpath.append(os.path.join(progrcd, f))

    # Use hgrc.d found in directory with hg.exe
    _processdir(os.path.join(os.path.dirname(filename), b'hgrc.d'))

    # treat a PROGRAMDATA directory as equivalent to /etc/mercurial
    programdata = encoding.environ.get(b'PROGRAMDATA')
    if programdata:
        programdata = os.path.join(programdata, b'Mercurial')
        _processdir(os.path.join(programdata, b'hgrc.d'))

        ini = os.path.join(programdata, b'mercurial.ini')
        if os.path.isfile(ini):
            rcpath.append(ini)

        ini = os.path.join(programdata, b'hgrc')
        if os.path.isfile(ini):
            rcpath.append(ini)

    # next look for a system rcpath in the registry
    value = util.lookupreg(
        # pytype: disable=module-attr
        b'SOFTWARE\\Mercurial',
        None,
        winreg.HKEY_LOCAL_MACHINE
        # pytype: enable=module-attr
    )
    if value and isinstance(value, bytes):
        value = util.localpath(value)
        for p in value.split(pycompat.ospathsep):
            if p.lower().endswith(b'mercurial.ini'):
                rcpath.append(p)
            else:
                _processdir(p)
    return rcpath


def userrcpath() -> List[bytes]:
    '''return os-specific hgrc search path to the user dir'''
    home = _legacy_expanduser(b'~')
    path = [os.path.join(home, b'mercurial.ini'), os.path.join(home, b'.hgrc')]
    userprofile = encoding.environ.get(b'USERPROFILE')
    if userprofile and userprofile != home:
        path.append(os.path.join(userprofile, b'mercurial.ini'))
        path.append(os.path.join(userprofile, b'.hgrc'))
    return path


def _legacy_expanduser(path: bytes) -> bytes:
    """Expand ~ and ~user constructs in the pre 3.8 style"""

    # Python 3.8+ changed the expansion of '~' from HOME to USERPROFILE.  See
    # https://bugs.python.org/issue36264.  It also seems to capitalize the drive
    # letter, as though it was processed through os.path.realpath().
    if not path.startswith(b'~'):
        return path

    i, n = 1, len(path)
    while i < n and path[i] not in b'\\/':
        i += 1

    if b'HOME' in encoding.environ:
        userhome = encoding.environ[b'HOME']
    elif b'USERPROFILE' in encoding.environ:
        userhome = encoding.environ[b'USERPROFILE']
    elif b'HOMEPATH' not in encoding.environ:
        return path
    else:
        try:
            drive = encoding.environ[b'HOMEDRIVE']
        except KeyError:
            drive = b''
        userhome = os.path.join(drive, encoding.environ[b'HOMEPATH'])

    if i != 1:  # ~user
        userhome = os.path.join(os.path.dirname(userhome), path[1:i])

    return userhome + path[i:]


def termsize(ui: "uimod.ui") -> Tuple[int, int]:
    return win32.termsize()