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2c318a1390
and relies much more on meta path finders to abstract out various parts of import. As part of this the semantics for import_module tightened up and now follow __import__ much more closely (biggest thing is that the 'package' argument must now already be imported, else a SystemError is raised).
140 lines
3.6 KiB
Python
140 lines
3.6 KiB
Python
"""A pure Python implementation of import.
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References on import:
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* Language reference
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http://docs.python.org/ref/import.html
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* __import__ function
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http://docs.python.org/lib/built-in-funcs.html
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* Packages
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http://www.python.org/doc/essays/packages.html
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* PEP 235: Import on Case-Insensitive Platforms
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http://www.python.org/dev/peps/pep-0235
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* PEP 275: Import Modules from Zip Archives
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http://www.python.org/dev/peps/pep-0273
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* PEP 302: New Import Hooks
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http://www.python.org/dev/peps/pep-0302/
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* PEP 328: Imports: Multi-line and Absolute/Relative
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http://www.python.org/dev/peps/pep-0328
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"""
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from . import _bootstrap
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# XXX Temporary functions that should eventually be removed.
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import os
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import re
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import tokenize
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def _set__import__():
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"""Set __import__ to an instance of Import."""
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global original__import__
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original__import__ = __import__
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__builtins__['__import__'] = _bootstrap._import
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def _reset__import__():
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"""Set __import__ back to the original implementation (assumes
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_set__import__ was called previously)."""
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__builtins__['__import__'] = original__import__
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# Bootstrap help #####################################################
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def _case_ok(directory, check):
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"""Check if the directory contains something matching 'check'.
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No check is done if the file/directory exists or not.
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"""
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if 'PYTHONCASEOK' in os.environ:
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return True
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elif check in os.listdir(directory):
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return True
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return False
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def _w_long(x):
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"""Convert a 32-bit integer to little-endian.
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XXX Temporary until marshal's long functions are exposed.
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"""
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x = int(x)
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int_bytes = []
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int_bytes.append(x & 0xFF)
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int_bytes.append((x >> 8) & 0xFF)
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int_bytes.append((x >> 16) & 0xFF)
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int_bytes.append((x >> 24) & 0xFF)
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return bytearray(int_bytes)
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def _r_long(int_bytes):
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"""Convert 4 bytes in little-endian to an integer.
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XXX Temporary until marshal's long function are exposed.
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"""
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x = int_bytes[0]
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x |= int_bytes[1] << 8
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x |= int_bytes[2] << 16
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x |= int_bytes[3] << 24
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return x
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# Required built-in modules.
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try:
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import posix as _os
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except ImportError:
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try:
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import nt as _os
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except ImportError:
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try:
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import os2 as _os
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except ImportError:
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raise ImportError('posix, nt, or os2 module required for importlib')
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_bootstrap._os = _os
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import imp, sys, marshal, errno, _fileio
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_bootstrap.imp = imp
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_bootstrap.sys = sys
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_bootstrap.marshal = marshal
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_bootstrap.errno = errno
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_bootstrap._fileio = _fileio
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import _warnings
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_bootstrap._warnings = _warnings
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from os import sep
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# For os.path.join replacement; pull from Include/osdefs.h:SEP .
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_bootstrap.path_sep = sep
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_bootstrap._case_ok = _case_ok
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marshal._w_long = _w_long
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marshal._r_long = _r_long
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# Public API #########################################################
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__import__ = _bootstrap._import
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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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level = 0
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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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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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return _bootstrap._gcd_import(name[level:], package, level)
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# XXX This should go away once the public API is done.
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from ._bootstrap import *
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