Mercurial > hg
view mercurial/__init__.py @ 29490:b4d117cee636
policy: add cffi policy for PyPy
This adds cffi policy in the case where we don't want to use C modules,
but instead we're happy to rely on cffi (bundled with pypy)
author | Maciej Fijalkowski <fijall@gmail.com> |
---|---|
date | Tue, 07 Jun 2016 15:35:58 +0200 |
parents | b3a677c82a35 |
children | 1c22400db72d |
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# __init__.py - Startup and module loading 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 imp import os import sys import zipimport from . import ( policy ) __all__ = [] modulepolicy = policy.policy # Modules that have both Python and C implementations. See also the # set of .py files under mercurial/pure/. _dualmodules = set([ 'mercurial.base85', 'mercurial.bdiff', 'mercurial.diffhelpers', 'mercurial.mpatch', 'mercurial.osutil', 'mercurial.parsers', ]) class hgimporter(object): """Object that conforms to import hook interface defined in PEP-302.""" def find_module(self, name, path=None): # We only care about modules that have both C and pure implementations. if name in _dualmodules: return self return None def load_module(self, name): mod = sys.modules.get(name, None) if mod: return mod mercurial = sys.modules['mercurial'] # The zip importer behaves sufficiently differently from the default # importer to warrant its own code path. loader = getattr(mercurial, '__loader__', None) if isinstance(loader, zipimport.zipimporter): def ziploader(*paths): """Obtain a zipimporter for a directory under the main zip.""" path = os.path.join(loader.archive, *paths) zl = sys.path_importer_cache.get(path) if not zl: zl = zipimport.zipimporter(path) return zl try: if modulepolicy in policy.policynoc: raise ImportError() zl = ziploader('mercurial') mod = zl.load_module(name) # Unlike imp, ziploader doesn't expose module metadata that # indicates the type of module. So just assume what we found # is OK (even though it could be a pure Python module). except ImportError: if modulepolicy == 'c': raise zl = ziploader('mercurial', 'pure') mod = zl.load_module(name) sys.modules[name] = mod return mod # Unlike the default importer which searches special locations and # sys.path, we only look in the directory where "mercurial" was # imported from. # imp.find_module doesn't support submodules (modules with "."). # Instead you have to pass the parent package's __path__ attribute # as the path argument. stem = name.split('.')[-1] try: if modulepolicy in policy.policynoc: raise ImportError() modinfo = imp.find_module(stem, mercurial.__path__) # The Mercurial installer used to copy files from # mercurial/pure/*.py to mercurial/*.py. Therefore, it's possible # for some installations to have .py files under mercurial/*. # Loading Python modules when we expected C versions could result # in a) poor performance b) loading a version from a previous # Mercurial version, potentially leading to incompatibility. Either # scenario is bad. So we verify that modules loaded from # mercurial/* are C extensions. If the current policy allows the # loading of .py modules, the module will be re-imported from # mercurial/pure/* below. if modinfo[2][2] != imp.C_EXTENSION: raise ImportError('.py version of %s found where C ' 'version should exist' % name) except ImportError: if modulepolicy == 'c': raise # Could not load the C extension and pure Python is allowed. So # try to load them. from . import pure modinfo = imp.find_module(stem, pure.__path__) if not modinfo: raise ImportError('could not find mercurial module %s' % name) mod = imp.load_module(name, *modinfo) sys.modules[name] = mod return mod # We automagically register our custom importer as a side-effect of loading. # This is necessary to ensure that any entry points are able to import # mercurial.* modules without having to perform this registration themselves. if not any(isinstance(x, hgimporter) for x in sys.meta_path): # meta_path is used before any implicit finders and before sys.path. sys.meta_path.insert(0, hgimporter())