view mercurial/scmwindows.py @ 37443:65250a66b55c

revlog: move censor logic into main revlog class

Previously, the revlog class implemented dummy methods for
various censor-related functionality. Revision censoring was
(and will continue to be) only possible on filelog instances.
So filelog implemented these methods to perform something
reasonable.

A problem with implementing censoring on filelog is that
it assumes filelog is a revlog. Upcoming work to formalize
the filelog interface will make this not true.

Furthermore, the censoring logic is security-sensitive. I
think action-at-a-distance with custom implementation of core
revlog APIs in derived classes is a bit dangerous. I think at
a minimum the censor logic should live in revlog.py.

I was tempted to created a "censored revlog" class that
basically pulled these methods out of filelog. But, I wasn't
a huge fan of overriding core methods in child classes. A
reason to do that would be performance. However, the censoring
code only comes into play when:

* hash verification fails
* delta generation
* applying deltas from changegroups

The new code is conditional on an instance attribute. So the
overhead for running the censored code when the revlog isn't
censorable is an attribute lookup. All of these operations are
at least a magnitude slower than a Python attribute lookup. So
there shouldn't be a performance concern.

Differential Revision: https://phab.mercurial-scm.org/D3151

from __future__ import absolute_import

import os

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

try:
    import _winreg as winreg
    winreg.CloseKey
except ImportError:
    import winreg

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

def systemrcpath():
    '''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), 'mercurial.ini')
    rcpath.append(progrc)
    # Use hgrc.d found in directory with hg.exe
    progrcd = os.path.join(os.path.dirname(filename), 'hgrc.d')
    if os.path.isdir(progrcd):
        for f, kind in util.listdir(progrcd):
            if f.endswith('.rc'):
                rcpath.append(os.path.join(progrcd, f))
    # else look for a system rcpath in the registry
    value = util.lookupreg('SOFTWARE\\Mercurial', None,
                           winreg.HKEY_LOCAL_MACHINE)
    if not isinstance(value, str) or not value:
        return rcpath
    value = util.localpath(value)
    for p in value.split(pycompat.ospathsep):
        if p.lower().endswith('mercurial.ini'):
            rcpath.append(p)
        elif os.path.isdir(p):
            for f, kind in util.listdir(p):
                if f.endswith('.rc'):
                    rcpath.append(os.path.join(p, f))
    return rcpath

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

def termsize(ui):
    return win32.termsize()