mirror of
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707 lines
24 KiB
Python
707 lines
24 KiB
Python
"""Utilities to support packages."""
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from collections import namedtuple
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from functools import singledispatch as simplegeneric
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import importlib
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import importlib.util
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import importlib.machinery
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import os
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import os.path
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import re
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import sys
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from types import ModuleType
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import warnings
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__all__ = [
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'get_importer', 'iter_importers', 'get_loader', 'find_loader',
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'walk_packages', 'iter_modules', 'get_data',
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'ImpImporter', 'ImpLoader', 'read_code', 'extend_path',
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'ModuleInfo',
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]
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ModuleInfo = namedtuple('ModuleInfo', 'module_finder name ispkg')
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ModuleInfo.__doc__ = 'A namedtuple with minimal info about a module.'
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def _get_spec(finder, name):
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"""Return the finder-specific module spec."""
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# Works with legacy finders.
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try:
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find_spec = finder.find_spec
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except AttributeError:
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loader = finder.find_module(name)
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if loader is None:
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return None
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return importlib.util.spec_from_loader(name, loader)
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else:
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return find_spec(name)
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def read_code(stream):
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# This helper is needed in order for the PEP 302 emulation to
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# correctly handle compiled files
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import marshal
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magic = stream.read(4)
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if magic != importlib.util.MAGIC_NUMBER:
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return None
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stream.read(12) # Skip rest of the header
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return marshal.load(stream)
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def walk_packages(path=None, prefix='', onerror=None):
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"""Yields ModuleInfo for all modules recursively
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on path, or, if path is None, all accessible modules.
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'path' should be either None or a list of paths to look for
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modules in.
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'prefix' is a string to output on the front of every module name
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on output.
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Note that this function must import all *packages* (NOT all
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modules!) on the given path, in order to access the __path__
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attribute to find submodules.
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'onerror' is a function which gets called with one argument (the
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name of the package which was being imported) if any exception
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occurs while trying to import a package. If no onerror function is
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supplied, ImportErrors are caught and ignored, while all other
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exceptions are propagated, terminating the search.
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Examples:
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# list all modules python can access
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walk_packages()
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# list all submodules of ctypes
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walk_packages(ctypes.__path__, ctypes.__name__+'.')
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"""
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def seen(p, m={}):
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if p in m:
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return True
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m[p] = True
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for info in iter_modules(path, prefix):
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yield info
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if info.ispkg:
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try:
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__import__(info.name)
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except ImportError:
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if onerror is not None:
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onerror(info.name)
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except Exception:
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if onerror is not None:
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onerror(info.name)
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else:
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raise
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else:
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path = getattr(sys.modules[info.name], '__path__', None) or []
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# don't traverse path items we've seen before
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path = [p for p in path if not seen(p)]
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yield from walk_packages(path, info.name+'.', onerror)
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def iter_modules(path=None, prefix=''):
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"""Yields ModuleInfo for all submodules on path,
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or, if path is None, all top-level modules on sys.path.
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'path' should be either None or a list of paths to look for
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modules in.
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'prefix' is a string to output on the front of every module name
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on output.
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"""
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if path is None:
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importers = iter_importers()
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elif isinstance(path, str):
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raise ValueError("path must be None or list of paths to look for "
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"modules in")
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else:
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importers = map(get_importer, path)
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yielded = {}
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for i in importers:
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for name, ispkg in iter_importer_modules(i, prefix):
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if name not in yielded:
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yielded[name] = 1
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yield ModuleInfo(i, name, ispkg)
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@simplegeneric
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def iter_importer_modules(importer, prefix=''):
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if not hasattr(importer, 'iter_modules'):
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return []
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return importer.iter_modules(prefix)
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# Implement a file walker for the normal importlib path hook
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def _iter_file_finder_modules(importer, prefix=''):
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if importer.path is None or not os.path.isdir(importer.path):
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return
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yielded = {}
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import inspect
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try:
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filenames = os.listdir(importer.path)
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except OSError:
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# ignore unreadable directories like import does
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filenames = []
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filenames.sort() # handle packages before same-named modules
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for fn in filenames:
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modname = inspect.getmodulename(fn)
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if modname=='__init__' or modname in yielded:
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continue
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path = os.path.join(importer.path, fn)
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ispkg = False
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if not modname and os.path.isdir(path) and '.' not in fn:
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modname = fn
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try:
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dircontents = os.listdir(path)
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except OSError:
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# ignore unreadable directories like import does
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dircontents = []
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for fn in dircontents:
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subname = inspect.getmodulename(fn)
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if subname=='__init__':
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ispkg = True
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break
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else:
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continue # not a package
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if modname and '.' not in modname:
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yielded[modname] = 1
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yield prefix + modname, ispkg
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iter_importer_modules.register(
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importlib.machinery.FileFinder, _iter_file_finder_modules)
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def _import_imp():
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global imp
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with warnings.catch_warnings():
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warnings.simplefilter('ignore', DeprecationWarning)
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imp = importlib.import_module('imp')
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class ImpImporter:
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"""PEP 302 Finder that wraps Python's "classic" import algorithm
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ImpImporter(dirname) produces a PEP 302 finder that searches that
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directory. ImpImporter(None) produces a PEP 302 finder that searches
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the current sys.path, plus any modules that are frozen or built-in.
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Note that ImpImporter does not currently support being used by placement
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on sys.meta_path.
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"""
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def __init__(self, path=None):
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global imp
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warnings.warn("This emulation is deprecated, use 'importlib' instead",
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DeprecationWarning)
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_import_imp()
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self.path = path
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def find_module(self, fullname, path=None):
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# Note: we ignore 'path' argument since it is only used via meta_path
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subname = fullname.split(".")[-1]
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if subname != fullname and self.path is None:
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return None
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if self.path is None:
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path = None
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else:
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path = [os.path.realpath(self.path)]
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try:
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file, filename, etc = imp.find_module(subname, path)
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except ImportError:
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return None
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return ImpLoader(fullname, file, filename, etc)
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def iter_modules(self, prefix=''):
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if self.path is None or not os.path.isdir(self.path):
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return
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yielded = {}
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import inspect
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try:
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filenames = os.listdir(self.path)
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except OSError:
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# ignore unreadable directories like import does
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filenames = []
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filenames.sort() # handle packages before same-named modules
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for fn in filenames:
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modname = inspect.getmodulename(fn)
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if modname=='__init__' or modname in yielded:
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continue
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path = os.path.join(self.path, fn)
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ispkg = False
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if not modname and os.path.isdir(path) and '.' not in fn:
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modname = fn
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try:
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dircontents = os.listdir(path)
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except OSError:
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# ignore unreadable directories like import does
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dircontents = []
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for fn in dircontents:
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subname = inspect.getmodulename(fn)
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if subname=='__init__':
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ispkg = True
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break
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else:
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continue # not a package
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if modname and '.' not in modname:
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yielded[modname] = 1
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yield prefix + modname, ispkg
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class ImpLoader:
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"""PEP 302 Loader that wraps Python's "classic" import algorithm
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"""
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code = source = None
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def __init__(self, fullname, file, filename, etc):
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warnings.warn("This emulation is deprecated, use 'importlib' instead",
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DeprecationWarning)
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_import_imp()
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self.file = file
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self.filename = filename
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self.fullname = fullname
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self.etc = etc
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def load_module(self, fullname):
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self._reopen()
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try:
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mod = imp.load_module(fullname, self.file, self.filename, self.etc)
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finally:
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if self.file:
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self.file.close()
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# Note: we don't set __loader__ because we want the module to look
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# normal; i.e. this is just a wrapper for standard import machinery
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return mod
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def get_data(self, pathname):
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with open(pathname, "rb") as file:
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return file.read()
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def _reopen(self):
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if self.file and self.file.closed:
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mod_type = self.etc[2]
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if mod_type==imp.PY_SOURCE:
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self.file = open(self.filename, 'r')
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elif mod_type in (imp.PY_COMPILED, imp.C_EXTENSION):
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self.file = open(self.filename, 'rb')
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def _fix_name(self, fullname):
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if fullname is None:
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fullname = self.fullname
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elif fullname != self.fullname:
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raise ImportError("Loader for module %s cannot handle "
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"module %s" % (self.fullname, fullname))
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return fullname
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def is_package(self, fullname):
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fullname = self._fix_name(fullname)
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return self.etc[2]==imp.PKG_DIRECTORY
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def get_code(self, fullname=None):
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fullname = self._fix_name(fullname)
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if self.code is None:
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mod_type = self.etc[2]
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if mod_type==imp.PY_SOURCE:
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source = self.get_source(fullname)
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self.code = compile(source, self.filename, 'exec')
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elif mod_type==imp.PY_COMPILED:
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self._reopen()
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try:
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self.code = read_code(self.file)
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finally:
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self.file.close()
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elif mod_type==imp.PKG_DIRECTORY:
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self.code = self._get_delegate().get_code()
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return self.code
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def get_source(self, fullname=None):
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fullname = self._fix_name(fullname)
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if self.source is None:
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mod_type = self.etc[2]
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if mod_type==imp.PY_SOURCE:
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self._reopen()
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try:
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self.source = self.file.read()
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finally:
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self.file.close()
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elif mod_type==imp.PY_COMPILED:
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if os.path.exists(self.filename[:-1]):
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with open(self.filename[:-1], 'r') as f:
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self.source = f.read()
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elif mod_type==imp.PKG_DIRECTORY:
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self.source = self._get_delegate().get_source()
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return self.source
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def _get_delegate(self):
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finder = ImpImporter(self.filename)
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spec = _get_spec(finder, '__init__')
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return spec.loader
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def get_filename(self, fullname=None):
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fullname = self._fix_name(fullname)
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mod_type = self.etc[2]
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if mod_type==imp.PKG_DIRECTORY:
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return self._get_delegate().get_filename()
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elif mod_type in (imp.PY_SOURCE, imp.PY_COMPILED, imp.C_EXTENSION):
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return self.filename
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return None
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try:
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import zipimport
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from zipimport import zipimporter
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def iter_zipimport_modules(importer, prefix=''):
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dirlist = sorted(zipimport._zip_directory_cache[importer.archive])
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_prefix = importer.prefix
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plen = len(_prefix)
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yielded = {}
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import inspect
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for fn in dirlist:
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if not fn.startswith(_prefix):
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continue
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fn = fn[plen:].split(os.sep)
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if len(fn)==2 and fn[1].startswith('__init__.py'):
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if fn[0] not in yielded:
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yielded[fn[0]] = 1
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yield prefix + fn[0], True
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if len(fn)!=1:
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continue
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modname = inspect.getmodulename(fn[0])
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if modname=='__init__':
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continue
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if modname and '.' not in modname and modname not in yielded:
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yielded[modname] = 1
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yield prefix + modname, False
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iter_importer_modules.register(zipimporter, iter_zipimport_modules)
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except ImportError:
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pass
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def get_importer(path_item):
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"""Retrieve a finder for the given path item
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The returned finder is cached in sys.path_importer_cache
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if it was newly created by a path hook.
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The cache (or part of it) can be cleared manually if a
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rescan of sys.path_hooks is necessary.
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"""
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try:
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importer = sys.path_importer_cache[path_item]
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except KeyError:
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for path_hook in sys.path_hooks:
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try:
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importer = path_hook(path_item)
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sys.path_importer_cache.setdefault(path_item, importer)
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break
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except ImportError:
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pass
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else:
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importer = None
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return importer
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def iter_importers(fullname=""):
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"""Yield finders for the given module name
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If fullname contains a '.', the finders will be for the package
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containing fullname, otherwise they will be all registered top level
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finders (i.e. those on both sys.meta_path and sys.path_hooks).
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If the named module is in a package, that package is imported as a side
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effect of invoking this function.
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If no module name is specified, all top level finders are produced.
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"""
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if fullname.startswith('.'):
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msg = "Relative module name {!r} not supported".format(fullname)
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raise ImportError(msg)
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if '.' in fullname:
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# Get the containing package's __path__
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pkg_name = fullname.rpartition(".")[0]
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pkg = importlib.import_module(pkg_name)
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path = getattr(pkg, '__path__', None)
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if path is None:
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return
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else:
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yield from sys.meta_path
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path = sys.path
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for item in path:
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yield get_importer(item)
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def get_loader(module_or_name):
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"""Get a "loader" object for module_or_name
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Returns None if the module cannot be found or imported.
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If the named module is not already imported, its containing package
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(if any) is imported, in order to establish the package __path__.
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"""
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if module_or_name in sys.modules:
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module_or_name = sys.modules[module_or_name]
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if module_or_name is None:
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return None
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if isinstance(module_or_name, ModuleType):
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module = module_or_name
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loader = getattr(module, '__loader__', None)
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if loader is not None:
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return loader
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if getattr(module, '__spec__', None) is None:
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return None
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fullname = module.__name__
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else:
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fullname = module_or_name
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return find_loader(fullname)
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def find_loader(fullname):
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"""Find a "loader" object for fullname
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This is a backwards compatibility wrapper around
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importlib.util.find_spec that converts most failures to ImportError
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and only returns the loader rather than the full spec
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"""
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if fullname.startswith('.'):
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msg = "Relative module name {!r} not supported".format(fullname)
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raise ImportError(msg)
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try:
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spec = importlib.util.find_spec(fullname)
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except (ImportError, AttributeError, TypeError, ValueError) as ex:
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# This hack fixes an impedance mismatch between pkgutil and
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# importlib, where the latter raises other errors for cases where
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# pkgutil previously raised ImportError
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msg = "Error while finding loader for {!r} ({}: {})"
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raise ImportError(msg.format(fullname, type(ex), ex)) from ex
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return spec.loader if spec is not None else None
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def extend_path(path, name):
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"""Extend a package's path.
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Intended use is to place the following code in a package's __init__.py:
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from pkgutil import extend_path
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__path__ = extend_path(__path__, __name__)
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This will add to the package's __path__ all subdirectories of
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directories on sys.path named after the package. This is useful
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if one wants to distribute different parts of a single logical
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package as multiple directories.
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It also looks for *.pkg files beginning where * matches the name
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argument. This feature is similar to *.pth files (see site.py),
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except that it doesn't special-case lines starting with 'import'.
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A *.pkg file is trusted at face value: apart from checking for
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duplicates, all entries found in a *.pkg file are added to the
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path, regardless of whether they are exist the filesystem. (This
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is a feature.)
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If the input path is not a list (as is the case for frozen
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packages) it is returned unchanged. The input path is not
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modified; an extended copy is returned. Items are only appended
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to the copy at the end.
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It is assumed that sys.path is a sequence. Items of sys.path that
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are not (unicode or 8-bit) strings referring to existing
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directories are ignored. Unicode items of sys.path that cause
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errors when used as filenames may cause this function to raise an
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exception (in line with os.path.isdir() behavior).
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"""
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if not isinstance(path, list):
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# This could happen e.g. when this is called from inside a
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# frozen package. Return the path unchanged in that case.
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return path
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sname_pkg = name + ".pkg"
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path = path[:] # Start with a copy of the existing path
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|
|
|
parent_package, _, final_name = name.rpartition('.')
|
|
if parent_package:
|
|
try:
|
|
search_path = sys.modules[parent_package].__path__
|
|
except (KeyError, AttributeError):
|
|
# We can't do anything: find_loader() returns None when
|
|
# passed a dotted name.
|
|
return path
|
|
else:
|
|
search_path = sys.path
|
|
|
|
for dir in search_path:
|
|
if not isinstance(dir, str):
|
|
continue
|
|
|
|
finder = get_importer(dir)
|
|
if finder is not None:
|
|
portions = []
|
|
if hasattr(finder, 'find_spec'):
|
|
spec = finder.find_spec(final_name)
|
|
if spec is not None:
|
|
portions = spec.submodule_search_locations or []
|
|
# Is this finder PEP 420 compliant?
|
|
elif hasattr(finder, 'find_loader'):
|
|
_, portions = finder.find_loader(final_name)
|
|
|
|
for portion in portions:
|
|
# XXX This may still add duplicate entries to path on
|
|
# case-insensitive filesystems
|
|
if portion not in path:
|
|
path.append(portion)
|
|
|
|
# XXX Is this the right thing for subpackages like zope.app?
|
|
# It looks for a file named "zope.app.pkg"
|
|
pkgfile = os.path.join(dir, sname_pkg)
|
|
if os.path.isfile(pkgfile):
|
|
try:
|
|
f = open(pkgfile)
|
|
except OSError as msg:
|
|
sys.stderr.write("Can't open %s: %s\n" %
|
|
(pkgfile, msg))
|
|
else:
|
|
with f:
|
|
for line in f:
|
|
line = line.rstrip('\n')
|
|
if not line or line.startswith('#'):
|
|
continue
|
|
path.append(line) # Don't check for existence!
|
|
|
|
return path
|
|
|
|
|
|
def get_data(package, resource):
|
|
"""Get a resource from a package.
|
|
|
|
This is a wrapper round the PEP 302 loader get_data API. The package
|
|
argument should be the name of a package, in standard module format
|
|
(foo.bar). The resource argument should be in the form of a relative
|
|
filename, using '/' as the path separator. The parent directory name '..'
|
|
is not allowed, and nor is a rooted name (starting with a '/').
|
|
|
|
The function returns a binary string, which is the contents of the
|
|
specified resource.
|
|
|
|
For packages located in the filesystem, which have already been imported,
|
|
this is the rough equivalent of
|
|
|
|
d = os.path.dirname(sys.modules[package].__file__)
|
|
data = open(os.path.join(d, resource), 'rb').read()
|
|
|
|
If the package cannot be located or loaded, or it uses a PEP 302 loader
|
|
which does not support get_data(), then None is returned.
|
|
"""
|
|
|
|
spec = importlib.util.find_spec(package)
|
|
if spec is None:
|
|
return None
|
|
loader = spec.loader
|
|
if loader is None or not hasattr(loader, 'get_data'):
|
|
return None
|
|
# XXX needs test
|
|
mod = (sys.modules.get(package) or
|
|
importlib._bootstrap._load(spec))
|
|
if mod is None or not hasattr(mod, '__file__'):
|
|
return None
|
|
|
|
# Modify the resource name to be compatible with the loader.get_data
|
|
# signature - an os.path format "filename" starting with the dirname of
|
|
# the package's __file__
|
|
parts = resource.split('/')
|
|
parts.insert(0, os.path.dirname(mod.__file__))
|
|
resource_name = os.path.join(*parts)
|
|
return loader.get_data(resource_name)
|
|
|
|
|
|
_DOTTED_WORDS = r'(?!\d)(\w+)(\.(?!\d)(\w+))*'
|
|
_NAME_PATTERN = re.compile(f'^(?P<pkg>{_DOTTED_WORDS})(?P<cln>:(?P<obj>{_DOTTED_WORDS})?)?$', re.U)
|
|
del _DOTTED_WORDS
|
|
|
|
def resolve_name(name):
|
|
"""
|
|
Resolve a name to an object.
|
|
|
|
It is expected that `name` will be a string in one of the following
|
|
formats, where W is shorthand for a valid Python identifier and dot stands
|
|
for a literal period in these pseudo-regexes:
|
|
|
|
W(.W)*
|
|
W(.W)*:(W(.W)*)?
|
|
|
|
The first form is intended for backward compatibility only. It assumes that
|
|
some part of the dotted name is a package, and the rest is an object
|
|
somewhere within that package, possibly nested inside other objects.
|
|
Because the place where the package stops and the object hierarchy starts
|
|
can't be inferred by inspection, repeated attempts to import must be done
|
|
with this form.
|
|
|
|
In the second form, the caller makes the division point clear through the
|
|
provision of a single colon: the dotted name to the left of the colon is a
|
|
package to be imported, and the dotted name to the right is the object
|
|
hierarchy within that package. Only one import is needed in this form. If
|
|
it ends with the colon, then a module object is returned.
|
|
|
|
The function will return an object (which might be a module), or raise one
|
|
of the following exceptions:
|
|
|
|
ValueError - if `name` isn't in a recognised format
|
|
ImportError - if an import failed when it shouldn't have
|
|
AttributeError - if a failure occurred when traversing the object hierarchy
|
|
within the imported package to get to the desired object)
|
|
"""
|
|
m = _NAME_PATTERN.match(name)
|
|
if not m:
|
|
raise ValueError(f'invalid format: {name!r}')
|
|
gd = m.groupdict()
|
|
if gd.get('cln'):
|
|
# there is a colon - a one-step import is all that's needed
|
|
mod = importlib.import_module(gd['pkg'])
|
|
parts = gd.get('obj')
|
|
parts = parts.split('.') if parts else []
|
|
else:
|
|
# no colon - have to iterate to find the package boundary
|
|
parts = name.split('.')
|
|
modname = parts.pop(0)
|
|
# first part *must* be a module/package.
|
|
mod = importlib.import_module(modname)
|
|
while parts:
|
|
p = parts[0]
|
|
s = f'{modname}.{p}'
|
|
try:
|
|
mod = importlib.import_module(s)
|
|
parts.pop(0)
|
|
modname = s
|
|
except ImportError:
|
|
break
|
|
# if we reach this point, mod is the module, already imported, and
|
|
# parts is the list of parts in the object hierarchy to be traversed, or
|
|
# an empty list if just the module is wanted.
|
|
result = mod
|
|
for p in parts:
|
|
result = getattr(result, p)
|
|
return result
|