mirror of https://github.com/python/cpython
52 lines
1.7 KiB
Python
52 lines
1.7 KiB
Python
"""Backport of importlib.import_module from 3.x."""
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# While not critical (and in no way guaranteed!), it would be nice to keep this
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# code compatible with Python 2.3.
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import sys
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def _resolve_name(name, package, level):
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"""Return the absolute name of the module to be imported."""
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level -= 1
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try:
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if package.count('.') < level:
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raise ValueError("attempted relative import beyond top-level "
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"package")
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except AttributeError:
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raise ValueError("'package' not set to a string")
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try:
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# rpartition is more "correct" and rfind is just as easy to use, but
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# neither are in Python 2.3.
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dot_rindex = package.rindex('.', level)
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base = package[:dot_rindex]
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except ValueError:
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base = package
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if name:
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return "%s.%s" % (base, name)
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else:
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return base
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def import_module(name, package=None):
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"""Import a module.
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The 'package' argument is required when performing a relative import. It
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specifies the package to use as the anchor point from which to resolve the
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relative import to an absolute import.
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"""
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if name.startswith('.'):
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if not package:
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raise TypeError("relative imports require the 'package' argument")
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level = 0
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for character in name:
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if character != '.':
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break
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level += 1
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name = _resolve_name(name[level:], package, level)
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# Try to import specifying the level to be as accurate as possible, but
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# realize that keyword arguments are not found in Python 2.3.
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try:
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__import__(name, level=0)
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except TypeError:
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__import__(name)
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return sys.modules[name]
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