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# policy.py - module policy logic for Mercurial.
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#
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# Copyright 2015 Gregory Szorc <gregory.szorc@gmail.com>
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#
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# This software may be used and distributed according to the terms of the
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# GNU General Public License version 2 or any later version.
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from __future__ import absolute_import
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import os
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import sys
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# Rules for how modules can be loaded. Values are:
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#
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# c - require C extensions
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# allow - allow pure Python implementation when C loading fails
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# cffi - required cffi versions (implemented within pure module)
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# cffi-allow - allow pure Python implementation if cffi version is missing
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# py - only load pure Python modules
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#
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# By default, require the C extensions for performance reasons.
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policy = b'c'
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policynoc = (b'cffi', b'cffi-allow', b'py')
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policynocffi = (b'c', b'py')
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try:
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from . import __modulepolicy__
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policy = __modulepolicy__.modulepolicy
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except ImportError:
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pass
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# PyPy doesn't load C extensions.
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#
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# The canonical way to do this is to test platform.python_implementation().
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# But we don't import platform and don't bloat for it here.
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if '__pypy__' in sys.builtin_module_names:
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policy = 'cffi'
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# Our C extensions aren't yet compatible with Python 3. So use pure Python
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# on Python 3 for now.
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if sys.version_info[0] >= 3:
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policy = b'py'
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# Environment variable can always force settings.
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if sys.version_info[0] >= 3:
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if 'HGMODULEPOLICY' in os.environ:
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policy = os.environ['HGMODULEPOLICY'].encode('utf-8')
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else:
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policy = os.environ.get('HGMODULEPOLICY', policy)
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