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cpython/Lib/imp.py
Brett Cannon 5a4c233a9e Issue #17358: imp.load_source() and load_compiled() should now return
modules which will typically work when reloaded.

A hack is used to support these functions as their API allowed them to
pass in a file object but then operate as if import had loaded them.
Unfortunately the hack kept a reference around for the file object
passed in which would be unusable on reload since it had been closed.
The solution is to simply use the hack for the initial load but then a
proper loader on the module so that imp.reload() at least has a chance
to work.
2013-04-28 11:53:26 -04:00

273 lines
9.1 KiB
Python

"""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,
get_frozen_object, is_frozen_package,
init_builtin, init_frozen, is_builtin, is_frozen,
_fix_co_filename)
try:
from _imp import load_dynamic
except ImportError:
# Platform doesn't support dynamic loading.
load_dynamic = None
# Directly exposed by this module
from importlib._bootstrap import new_module
from importlib._bootstrap import cache_from_source, source_from_cache
from importlib import _bootstrap
from importlib import machinery
import os
import sys
import tokenize
import warnings
# 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_magic():
"""Return the magic number for .pyc or .pyo files."""
return _bootstrap._MAGIC_BYTES
def get_tag():
"""Return the magic tag for .pyc or .pyo files."""
return sys.implementation.cache_tag
def get_suffixes():
warnings.warn('imp.get_suffixes() is deprecated; use the constants '
'defined on importlib.machinery instead',
DeprecationWarning, 2)
extensions = [(s, 'rb', C_EXTENSION) for s in machinery.EXTENSION_SUFFIXES]
source = [(s, 'U', PY_SOURCE) for s in machinery.SOURCE_SUFFIXES]
bytecode = [(s, 'rb', PY_COMPILED) for s in machinery.BYTECODE_SUFFIXES]
return extensions + source + bytecode
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()."""
def load_source(name, pathname, file=None):
msg = ('imp.load_source() is deprecated; use '
'importlib.machinery.SourceFileLoader(name, pathname).load_module()'
' instead')
warnings.warn(msg, DeprecationWarning, 2)
_LoadSourceCompatibility(name, pathname, file).load_module(name)
module = sys.modules[name]
# To allow reloading to potentially work, use a non-hacked loader which
# won't rely on a now-closed file object.
module.__loader__ = _bootstrap.SourceFileLoader(name, pathname)
return module
class _LoadCompiledCompatibility(_HackedGetData,
_bootstrap.SourcelessFileLoader):
"""Compatibility support for implementing load_compiled()."""
def load_compiled(name, pathname, file=None):
msg = ('imp.load_compiled() is deprecated; use '
'importlib.machinery.SourcelessFileLoader(name, pathname).'
'load_module() instead ')
warnings.warn(msg, DeprecationWarning, 2)
_LoadCompiledCompatibility(name, pathname, file).load_module(name)
module = sys.modules[name]
# To allow reloading to potentially work, use a non-hacked loader which
# won't rely on a now-closed file object.
module.__loader__ = _bootstrap.SourcelessFileLoader(name, pathname)
return module
def load_package(name, path):
msg = ('imp.load_package() is deprecated; use either '
'importlib.machinery.SourceFileLoader() or '
'importlib.machinery.SourcelessFileLoader() instead')
warnings.warn(msg, DeprecationWarning, 2)
if os.path.isdir(path):
extensions = (machinery.SOURCE_SUFFIXES[:] +
machinery.BYTECODE_SUFFIXES[:])
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)
def load_module(name, file, filename, details):
"""**DEPRECATED**
Load a module, given information returned by find_module().
The module name must include the full package name, if any.
"""
suffix, mode, type_ = details
with warnings.catch_warnings():
warnings.simplefilter('ignore')
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, C_EXTENSION}:
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_ == C_EXTENSION and load_dynamic is not None:
return load_dynamic(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):
"""**DEPRECATED**
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', machinery.BYTECODE_SUFFIXES[0]]:
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)
with warnings.catch_warnings():
warnings.simplefilter('ignore')
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(_bootstrap._ERR_MSG.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