__init__.py
129 lines
| 4.7 KiB
| text/x-python
|
PythonLexer
/ mercurial / __init__.py
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r27220 | # __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 | ||||
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r27225 | import zipimport | ||
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r27220 | |||
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r29266 | from . import ( | ||
policy | ||||
) | ||||
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r27220 | __all__ = [] | ||
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r29266 | modulepolicy = policy.policy | ||
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r27220 | |||
# 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'] | ||||
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r27225 | # 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: | ||||
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r29490 | if modulepolicy in policy.policynoc: | ||
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r27225 | 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 | ||||
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r27220 | # 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: | ||||
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r29490 | if modulepolicy in policy.policynoc: | ||
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r27220 | 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. | ||||
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r27223 | if modinfo[2][2] != imp.C_EXTENSION: | ||
raise ImportError('.py version of %s found where C ' | ||||
'version should exist' % name) | ||||
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r27220 | |||
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()) | ||||