mirror of
https://github.com/kennethreitz/requests3.git
synced 2026-06-05 23:10:16 +00:00
Ian Cordasco
81 lines
2.8 KiB
Python
81 lines
2.8 KiB
Python
"""
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pip._vendor is for vendoring dependencies of pip to prevent needing pip to
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depend on something external.
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Files inside of pip._vendor should be considered immutable and should only be
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updated to versions from upstream.
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"""
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from __future__ import absolute_import
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import sys
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class VendorAlias(object):
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def __init__(self):
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self._vendor_name = __name__
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self._vendor_pkg = self._vendor_name + "."
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def find_module(self, fullname, path=None):
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if fullname.startswith(self._vendor_pkg):
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return self
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def load_module(self, name):
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# Ensure that this only works for the vendored name
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if not name.startswith(self._vendor_pkg):
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raise ImportError(
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"Cannot import %s, must be a subpackage of '%s'." % (
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name, self._vendor_name,
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)
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)
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# Check to see if we already have this item in sys.modules, if we do
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# then simply return that.
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if name in sys.modules:
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return sys.modules[name]
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# Check to see if we can import the vendor name
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try:
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# We do this dance here because we want to try and import this
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# module without hitting a recursion error because of a bunch of
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# VendorAlias instances on sys.meta_path
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real_meta_path = sys.meta_path[:]
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try:
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sys.meta_path = [
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m for m in sys.meta_path
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if not isinstance(m, VendorAlias)
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]
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__import__(name)
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module = sys.modules[name]
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finally:
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# Re-add any additions to sys.meta_path that were made while
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# during the import we just did, otherwise things like
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# pip._vendor.six.moves will fail.
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for m in sys.meta_path:
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if m not in real_meta_path:
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real_meta_path.append(m)
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# Restore sys.meta_path with any new items.
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sys.meta_path = real_meta_path
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except ImportError:
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# We can't import the vendor name, so we'll try to import the
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# "real" name.
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real_name = name[len(self._vendor_pkg):]
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try:
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__import__(real_name)
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module = sys.modules[real_name]
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except ImportError:
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raise ImportError("No module named '%s'" % (name,))
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# If we've gotten here we've found the module we're looking for, either
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# as part of our vendored package, or as the real name, so we'll add
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# it to sys.modules as the vendored name so that we don't have to do
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# the lookup again.
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sys.modules[name] = module
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# Finally, return the loaded module
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return module
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sys.meta_path.append(VendorAlias())
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