view mercurial/policy.py @ 30444:b1ce25a40826

posix: move checkexec test file to .hg/cache

This avoids unnecessary churn in the working directory.

It is not necessarily a fully valid assumption that .hg/cache is on the same
filesystem as the working directory, but I think it is an acceptable
approximation. It could also be the case that different parts of the working
directory is on different mount points so checking in the root folder could
also be wrong.

# policy.py - module policy logic for Mercurial.
#
# Copyright 2015 Gregory Szorc <[e-mail]>
#
# 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, require the C extensions for performance reasons.
policy = 'c'
policynoc = ('cffi', 'cffi-allow', 'py')
policynocffi = ('c', 'py')

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 '__pypy__' in sys.builtin_module_names:
    policy = '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 = 'py'

# Environment variable can always force settings.
policy = os.environ.get('HGMODULEPOLICY', policy)