cpython/Lib/imp.py

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"""This module provides the components needed to build your own __import__
function. Undocumented functions are obsolete.
In most cases it is preferred you consider using the importlib module's
functionality over this module.
"""
# (Probably) need to stay in _imp
from _imp import (lock_held, acquire_lock, release_lock,
load_dynamic, get_frozen_object, is_frozen_package,
init_builtin, init_frozen, is_builtin, is_frozen,
_fix_co_filename, extension_suffixes)
# Could move out of _imp, but not worth the code
from _imp import get_magic, get_tag
from importlib._bootstrap import new_module
from importlib._bootstrap import cache_from_source
from importlib import _bootstrap
import os
import sys
import tokenize
# XXX "deprecate" once find_module(), load_module(), and get_suffixes() are
# deprecated.
SEARCH_ERROR = 0
PY_SOURCE = 1
PY_COMPILED = 2
C_EXTENSION = 3
PY_RESOURCE = 4
PKG_DIRECTORY = 5
C_BUILTIN = 6
PY_FROZEN = 7
PY_CODERESOURCE = 8
IMP_HOOK = 9
def get_suffixes():
extensions = [(s, 'rb', C_EXTENSION) for s in extension_suffixes()]
source = [(s, 'U', PY_SOURCE) for s in _bootstrap._SOURCE_SUFFIXES]
bytecode = [(_bootstrap._BYTECODE_SUFFIX, 'rb', PY_COMPILED)]
return extensions + source + bytecode
def source_from_cache(path):
"""Given the path to a .pyc./.pyo file, return the path to its .py file.
The .pyc/.pyo file does not need to exist; this simply returns the path to
the .py file calculated to correspond to the .pyc/.pyo file. If path does
not conform to PEP 3147 format, ValueError will be raised.
"""
head, pycache_filename = os.path.split(path)
head, pycache = os.path.split(head)
if pycache != _bootstrap._PYCACHE:
raise ValueError('{} not bottom-level directory in '
'{!r}'.format(_bootstrap._PYCACHE, path))
if pycache_filename.count('.') != 2:
raise ValueError('expected only 2 dots in '
'{!r}'.format(pycache_filename))
base_filename = pycache_filename.partition('.')[0]
return os.path.join(head, base_filename + _bootstrap._SOURCE_SUFFIXES[0])
class NullImporter:
"""Null import object."""
def __init__(self, path):
if path == '':
raise ImportError('empty pathname', path='')
elif os.path.isdir(path):
raise ImportError('existing directory', path=path)
def find_module(self, fullname):
"""Always returns None."""
return None
class _HackedGetData:
"""Compatibiilty support for 'file' arguments of various load_*()
functions."""
def __init__(self, fullname, path, file=None):
super().__init__(fullname, path)
self.file = file
def get_data(self, path):
"""Gross hack to contort loader to deal w/ load_*()'s bad API."""
if self.file and path == self.path:
with self.file:
# Technically should be returning bytes, but
# SourceLoader.get_code() just passed what is returned to
# compile() which can handle str. And converting to bytes would
# require figuring out the encoding to decode to and
# tokenize.detect_encoding() only accepts bytes.
return self.file.read()
else:
return super().get_data(path)
class _LoadSourceCompatibility(_HackedGetData, _bootstrap.SourceFileLoader):
"""Compatibility support for implementing load_source()."""
# XXX deprecate after better API exposed in importlib
def load_source(name, pathname, file=None):
return _LoadSourceCompatibility(name, pathname, file).load_module(name)
class _LoadCompiledCompatibility(_HackedGetData,
_bootstrap.SourcelessFileLoader):
"""Compatibility support for implementing load_compiled()."""
# XXX deprecate
def load_compiled(name, pathname, file=None):
return _LoadCompiledCompatibility(name, pathname, file).load_module(name)
# XXX deprecate
def load_package(name, path):
if os.path.isdir(path):
extensions = _bootstrap._SOURCE_SUFFIXES + [_bootstrap._BYTECODE_SUFFIX]
for extension in extensions:
path = os.path.join(path, '__init__'+extension)
if os.path.exists(path):
break
else:
raise ValueError('{!r} is not a package'.format(path))
return _bootstrap.SourceFileLoader(name, path).load_module(name)
# XXX deprecate
def load_module(name, file, filename, details):
"""Load a module, given information returned by find_module().
The module name must include the full package name, if any.
"""
suffix, mode, type_ = details
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if mode and (not mode.startswith(('r', 'U')) or '+' in mode):
raise ValueError('invalid file open mode {!r}'.format(mode))
elif file is None and type_ in {PY_SOURCE, PY_COMPILED}:
msg = 'file object required for import (type code {})'.format(type_)
raise ValueError(msg)
elif type_ == PY_SOURCE:
return load_source(name, filename, file)
elif type_ == PY_COMPILED:
return load_compiled(name, filename, file)
elif type_ == PKG_DIRECTORY:
return load_package(name, filename)
elif type_ == C_BUILTIN:
return init_builtin(name)
elif type_ == PY_FROZEN:
return init_frozen(name)
else:
msg = "Don't know how to import {} (type code {}".format(name, type_)
raise ImportError(msg, name=name)
def find_module(name, path=None):
"""Search for a module.
If path is omitted or None, search for a built-in, frozen or special
module and continue search in sys.path. The module name cannot
contain '.'; to search for a submodule of a package, pass the
submodule name and the package's __path__.
"""
if not isinstance(name, str):
raise TypeError("'name' must be a str, not {}".format(type(name)))
elif not isinstance(path, (type(None), list)):
# Backwards-compatibility
raise RuntimeError("'list' must be None or a list, "
"not {}".format(type(name)))
if path is None:
if is_builtin(name):
return None, None, ('', '', C_BUILTIN)
elif is_frozen(name):
return None, None, ('', '', PY_FROZEN)
else:
path = sys.path
for entry in path:
package_directory = os.path.join(entry, name)
for suffix in ['.py', _bootstrap._BYTECODE_SUFFIX]:
package_file_name = '__init__' + suffix
file_path = os.path.join(package_directory, package_file_name)
if os.path.isfile(file_path):
return None, package_directory, ('', '', PKG_DIRECTORY)
for suffix, mode, type_ in get_suffixes():
file_name = name + suffix
file_path = os.path.join(entry, file_name)
if os.path.isfile(file_path):
break
else:
continue
break # Break out of outer loop when breaking out of inner loop.
else:
raise ImportError('No module name {!r}'.format(name), name=name)
encoding = None
if mode == 'U':
with open(file_path, 'rb') as file:
encoding = tokenize.detect_encoding(file.readline)[0]
file = open(file_path, mode, encoding=encoding)
return file, file_path, (suffix, mode, type_)
_RELOADING = {}
def reload(module):
"""Reload the module and return it.
The module must have been successfully imported before.
"""
if not module or type(module) != type(sys):
raise TypeError("reload() argument must be module")
name = module.__name__
if name not in sys.modules:
msg = "module {} not in sys.modules"
raise ImportError(msg.format(name), name=name)
if name in _RELOADING:
return _RELOADING[name]
_RELOADING[name] = module
try:
parent_name = name.rpartition('.')[0]
if parent_name and parent_name not in sys.modules:
msg = "parent {!r} not in sys.modules"
raise ImportError(msg.format(parentname), name=parent_name)
return module.__loader__.load_module(name)
finally:
try:
del _RELOADING[name]
except KeyError:
pass