/usr/lib/python2.7/dist-packages/mercurial/policy.py is in mercurial-common 4.5.3-1ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 | # policy.py - module policy logic for Mercurial.
#
# Copyright 2015 Gregory Szorc <gregory.szorc@gmail.com>
#
# 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 absolute_import
import os
import sys
# Rules for how modules can be loaded. Values are:
#
# c - require C extensions
# allow - allow pure Python implementation when C loading fails
# cffi - required cffi versions (implemented within pure module)
# cffi-allow - allow pure Python implementation if cffi version is missing
# py - only load pure Python modules
#
# By default, fall back to the pure modules so the in-place build can
# run without recompiling the C extensions. This will be overridden by
# __modulepolicy__ generated by setup.py.
policy = b'allow'
_packageprefs = {
# policy: (versioned package, pure package)
b'c': (r'cext', None),
b'allow': (r'cext', r'pure'),
b'cffi': (r'cffi', None),
b'cffi-allow': (r'cffi', r'pure'),
b'py': (None, r'pure'),
}
try:
from . import __modulepolicy__
policy = __modulepolicy__.modulepolicy
except ImportError:
pass
# PyPy doesn't load C extensions.
#
# The canonical way to do this is to test platform.python_implementation().
# But we don't import platform and don't bloat for it here.
if r'__pypy__' in sys.builtin_module_names:
policy = b'cffi'
# Our C extensions aren't yet compatible with Python 3. So use pure Python
# on Python 3 for now.
if sys.version_info[0] >= 3:
policy = b'py'
# Environment variable can always force settings.
if sys.version_info[0] >= 3:
if r'HGMODULEPOLICY' in os.environ:
policy = os.environ[r'HGMODULEPOLICY'].encode(r'utf-8')
else:
policy = os.environ.get(r'HGMODULEPOLICY', policy)
def _importfrom(pkgname, modname):
# from .<pkgname> import <modname> (where . is looked through this module)
fakelocals = {}
pkg = __import__(pkgname, globals(), fakelocals, [modname], level=1)
try:
fakelocals[modname] = mod = getattr(pkg, modname)
except AttributeError:
raise ImportError(r'cannot import name %s' % modname)
# force import; fakelocals[modname] may be replaced with the real module
getattr(mod, r'__doc__', None)
return fakelocals[modname]
# keep in sync with "version" in C modules
_cextversions = {
(r'cext', r'base85'): 1,
(r'cext', r'bdiff'): 1,
(r'cext', r'diffhelpers'): 1,
(r'cext', r'mpatch'): 1,
(r'cext', r'osutil'): 3,
(r'cext', r'parsers'): 4,
}
# map import request to other package or module
_modredirects = {
(r'cext', r'charencode'): (r'cext', r'parsers'),
(r'cffi', r'base85'): (r'pure', r'base85'),
(r'cffi', r'charencode'): (r'pure', r'charencode'),
(r'cffi', r'diffhelpers'): (r'pure', r'diffhelpers'),
(r'cffi', r'parsers'): (r'pure', r'parsers'),
}
def _checkmod(pkgname, modname, mod):
expected = _cextversions.get((pkgname, modname))
actual = getattr(mod, r'version', None)
if actual != expected:
raise ImportError(r'cannot import module %s.%s '
r'(expected version: %d, actual: %r)'
% (pkgname, modname, expected, actual))
def importmod(modname):
"""Import module according to policy and check API version"""
try:
verpkg, purepkg = _packageprefs[policy]
except KeyError:
raise ImportError(r'invalid HGMODULEPOLICY %r' % policy)
assert verpkg or purepkg
if verpkg:
pn, mn = _modredirects.get((verpkg, modname), (verpkg, modname))
try:
mod = _importfrom(pn, mn)
if pn == verpkg:
_checkmod(pn, mn, mod)
return mod
except ImportError:
if not purepkg:
raise
pn, mn = _modredirects.get((purepkg, modname), (purepkg, modname))
return _importfrom(pn, mn)
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