policy.py
106 lines
| 3.4 KiB
| text/x-python
|
PythonLexer
/ mercurial / policy.py
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r29266 | # 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 | ||||
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r29490 | # cffi - required cffi versions (implemented within pure module) | ||
# cffi-allow - allow pure Python implementation if cffi version is missing | ||||
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r29266 | # py - only load pure Python modules | ||
# | ||||
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r32251 | # 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' | ||||
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r31361 | policynoc = (b'cffi', b'cffi-allow', b'py') | ||
policynocffi = (b'c', b'py') | ||||
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r32366 | _packageprefs = { | ||
# policy: (versioned package, pure package) | ||||
b'c': (r'cext', None), | ||||
b'allow': (r'cext', r'pure'), | ||||
b'cffi': (None, r'pure'), # TODO: (r'cffi', None) | ||||
b'cffi-allow': (None, r'pure'), # TODO: (r'cffi', r'pure') | ||||
b'py': (None, r'pure'), | ||||
} | ||||
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r29490 | |||
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r29266 | 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. | ||||
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r32205 | if r'__pypy__' in sys.builtin_module_names: | ||
policy = b'cffi' | ||||
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r29266 | |||
# 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: | ||||
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r31308 | policy = b'py' | ||
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r29266 | |||
# Environment variable can always force settings. | ||||
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r31361 | if sys.version_info[0] >= 3: | ||
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r32205 | if r'HGMODULEPOLICY' in os.environ: | ||
policy = os.environ[r'HGMODULEPOLICY'].encode(r'utf-8') | ||||
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r31361 | else: | ||
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r32205 | policy = os.environ.get(r'HGMODULEPOLICY', policy) | ||
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r32366 | |||
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] | ||||
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r32428 | # keep in sync with "version" in C modules | ||
_cextversions = { | ||||
r'base85': 1, | ||||
r'bdiff': 1, | ||||
r'diffhelpers': 1, | ||||
r'mpatch': 1, | ||||
r'osutil': 1, | ||||
r'parsers': 1, | ||||
} | ||||
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r32366 | def _checkmod(pkgname, modname, mod): | ||
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r32428 | expected = _cextversions.get(modname) | ||
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r32366 | 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: | ||||
try: | ||||
mod = _importfrom(verpkg, modname) | ||||
_checkmod(verpkg, modname, mod) | ||||
return mod | ||||
except ImportError: | ||||
if not purepkg: | ||||
raise | ||||
return _importfrom(purepkg, modname) | ||||