dill/session.py - third_party/github.com/uqfoundation/dill - Git at Google

 #!/usr/bin/env python
 #
 # Author: Mike McKerns (mmckerns @caltech and @uqfoundation)
 # Author: Leonardo Gama (@leogama)
 # Copyright (c) 2008-2015 California Institute of Technology.
 # Copyright (c) 2016-2022 The Uncertainty Quantification Foundation.
 # License: 3-clause BSD.  The full license text is available at:
 #  - https://github.com/uqfoundation/dill/blob/master/LICENSE
 """
 Pickle and restore the intepreter session.
 """

 __all__ = [
     'dump_module', 'load_module', 'load_module_asdict',
     'dump_session', 'load_session' # backward compatibility
 ]

 import re
 import sys
 import warnings

 from dill import _dill, Pickler, Unpickler
 from ._dill import (
     BuiltinMethodType, FunctionType, MethodType, ModuleType, TypeType,
     _import_module, _is_builtin_module, _is_imported_module, _main_module,
     _reverse_typemap, __builtin__,
 )

 # Type hints.
 from typing import Optional, Union

 import pathlib
 import tempfile

 TEMPDIR = pathlib.PurePath(tempfile.gettempdir())

 def _module_map():
     """get map of imported modules"""
     from collections import defaultdict
     from types import SimpleNamespace
     modmap = SimpleNamespace(
         by_name=defaultdict(list),
         by_id=defaultdict(list),
         top_level={},
     )
     for modname, module in sys.modules.items():
         if modname in ('__main__', '__mp_main__') or not isinstance(module, ModuleType):
             continue
         if '.' not in modname:
             modmap.top_level[id(module)] = modname
         for objname, modobj in module.__dict__.items():
             modmap.by_name[objname].append((modobj, modname))
             modmap.by_id[id(modobj)].append((modobj, objname, modname))
     return modmap

 IMPORTED_AS_TYPES = (ModuleType, TypeType, FunctionType, MethodType, BuiltinMethodType)
 if 'PyCapsuleType' in _reverse_typemap:
     IMPORTED_AS_TYPES += (_reverse_typemap['PyCapsuleType'],)
 IMPORTED_AS_MODULES = ('ctypes', 'typing', 'subprocess', 'threading',
                                r'concurrent\.futures(\.\w+)?', r'multiprocessing(\.\w+)?')
 IMPORTED_AS_MODULES = tuple(re.compile(x) for x in IMPORTED_AS_MODULES)

 def _lookup_module(modmap, name, obj, main_module):
     """lookup name or id of obj if module is imported"""
     for modobj, modname in modmap.by_name[name]:
         if modobj is obj and sys.modules[modname] is not main_module:
             return modname, name
     __module__ = getattr(obj, '__module__', None)
     if isinstance(obj, IMPORTED_AS_TYPES) or (__module__ is not None
             and any(regex.fullmatch(__module__) for regex in IMPORTED_AS_MODULES)):
         for modobj, objname, modname in modmap.by_id[id(obj)]:
             if sys.modules[modname] is not main_module:
                 return modname, objname
     return None, None

 def _stash_modules(main_module):
     modmap = _module_map()
     newmod = ModuleType(main_module.__name__)

     imported = []
     imported_as = []
     imported_top_level = []  # keep separated for backward compatibility
     original = {}
     for name, obj in main_module.__dict__.items():
         if obj is main_module:
             original[name] = newmod  # self-reference
         elif obj is main_module.__dict__:
             original[name] = newmod.__dict__
         # Avoid incorrectly matching a singleton value in another package (ex.: __doc__).
         elif any(obj is singleton for singleton in (None, False, True)) \
                 or isinstance(obj, ModuleType) and _is_builtin_module(obj):  # always saved by ref
             original[name] = obj
         else:
             source_module, objname = _lookup_module(modmap, name, obj, main_module)
             if source_module is not None:
                 if objname == name:
                     imported.append((source_module, name))
                 else:
                     imported_as.append((source_module, objname, name))
             else:
                 try:
                     imported_top_level.append((modmap.top_level[id(obj)], name))
                 except KeyError:
                     original[name] = obj

     if len(original) < len(main_module.__dict__):
         newmod.__dict__.update(original)
         newmod.__dill_imported = imported
         newmod.__dill_imported_as = imported_as
         newmod.__dill_imported_top_level = imported_top_level
         if getattr(newmod, '__loader__', None) is None and _is_imported_module(main_module):
             # Trick _is_imported_module() to force saving as an imported module.
             newmod.__loader__ = True  # will be discarded by save_module()
         return newmod
     else:
         return main_module

 def _restore_modules(unpickler, main_module):
     try:
         for modname, name in main_module.__dict__.pop('__dill_imported'):
             main_module.__dict__[name] = unpickler.find_class(modname, name)
         for modname, objname, name in main_module.__dict__.pop('__dill_imported_as'):
             main_module.__dict__[name] = unpickler.find_class(modname, objname)
         for modname, name in main_module.__dict__.pop('__dill_imported_top_level'):
             main_module.__dict__[name] = __import__(modname)
     except KeyError:
         pass

 #NOTE: 06/03/15 renamed main_module to main
 def dump_module(
     filename = str(TEMPDIR/'session.pkl'),
     module: Optional[Union[ModuleType, str]] = None,
     refimported: bool = False,
     **kwds
 ) -> None:
     """Pickle the current state of :py:mod:`__main__` or another module to a file.

     Save the contents of :py:mod:`__main__` (e.g. from an interactive
     interpreter session), an imported module, or a module-type object (e.g.
     built with :py:class:`~types.ModuleType`), to a file. The pickled
     module can then be restored with the function :py:func:`load_module`.

     Parameters:
         filename: a path-like object or a writable stream.
         module: a module object or the name of an importable module. If `None`
             (the default), :py:mod:`__main__` is saved.
         refimported: if `True`, all objects identified as having been imported
             into the module's namespace are saved by reference. *Note:* this is
             similar but independent from ``dill.settings[`byref`]``, as
             ``refimported`` refers to virtually all imported objects, while
             ``byref`` only affects select objects.
         **kwds: extra keyword arguments passed to :py:class:`Pickler()`.

     Raises:
        :py:exc:`PicklingError`: if pickling fails.

     Examples:

         - Save current interpreter session state:

           >>> import dill
           >>> squared = lambda x: x*x
           >>> dill.dump_module() # save state of __main__ to /tmp/session.pkl

         - Save the state of an imported/importable module:

           >>> import dill
           >>> import pox
           >>> pox.plus_one = lambda x: x+1
           >>> dill.dump_module('pox_session.pkl', module=pox)

         - Save the state of a non-importable, module-type object:

           >>> import dill
           >>> from types import ModuleType
           >>> foo = ModuleType('foo')
           >>> foo.values = [1,2,3]
           >>> import math
           >>> foo.sin = math.sin
           >>> dill.dump_module('foo_session.pkl', module=foo, refimported=True)

         - Restore the state of the saved modules:

           >>> import dill
           >>> dill.load_module()
           >>> squared(2)
           4
           >>> pox = dill.load_module('pox_session.pkl')
           >>> pox.plus_one(1)
           2
           >>> foo = dill.load_module('foo_session.pkl')
           >>> [foo.sin(x) for x in foo.values]
           [0.8414709848078965, 0.9092974268256817, 0.1411200080598672]

     *Changed in version 0.3.6:* Function ``dump_session()`` was renamed to
     ``dump_module()``.  Parameters ``main`` and ``byref`` were renamed to
     ``module`` and ``refimported``, respectively.

     Note:
         Currently, ``dill.settings['byref']`` and ``dill.settings['recurse']``
         don't apply to this function.`
     """
     for old_par, par in [('main', 'module'), ('byref', 'refimported')]:
         if old_par in kwds:
             message = "The argument %r has been renamed %r" % (old_par, par)
             if old_par == 'byref':
                 message += " to distinguish it from dill.settings['byref']"
             warnings.warn(message + ".", PendingDeprecationWarning)
             if locals()[par]:  # the defaults are None and False
                 raise TypeError("both %r and %r arguments were used" % (par, old_par))
     refimported = kwds.pop('byref', refimported)
     module = kwds.pop('main', module)

     from .settings import settings
     protocol = settings['protocol']
     main = module
     if main is None:
         main = _main_module
     elif isinstance(main, str):
         main = _import_module(main)
     if not isinstance(main, ModuleType):
         raise TypeError("%r is not a module" % main)
     if hasattr(filename, 'write'):
         file = filename
     else:
         file = open(filename, 'wb')
     try:
         pickler = Pickler(file, protocol, **kwds)
         pickler._original_main = main
         if refimported:
             main = _stash_modules(main)
         pickler._main = main     #FIXME: dill.settings are disabled
         pickler._byref = False   # disable pickling by name reference
         pickler._recurse = False # disable pickling recursion for globals
         pickler._session = True  # is best indicator of when pickling a session
         pickler._first_pass = True
         pickler._main_modified = main is not pickler._original_main
         pickler.dump(main)
     finally:
         if file is not filename:  # if newly opened file
             file.close()
     return

 # Backward compatibility.
 def dump_session(filename=str(TEMPDIR/'session.pkl'), main=None, byref=False, **kwds):
     warnings.warn("dump_session() has been renamed dump_module()", PendingDeprecationWarning)
     dump_module(filename, module=main, refimported=byref, **kwds)
 dump_session.__doc__ = dump_module.__doc__

 class _PeekableReader:
     """lightweight stream wrapper that implements peek()"""
     def __init__(self, stream):
         self.stream = stream
     def read(self, n):
         return self.stream.read(n)
     def readline(self):
         return self.stream.readline()
     def tell(self):
         return self.stream.tell()
     def close(self):
         return self.stream.close()
     def peek(self, n):
         stream = self.stream
         try:
             if hasattr(stream, 'flush'): stream.flush()
             position = stream.tell()
             stream.seek(position)  # assert seek() works before reading
             chunk = stream.read(n)
             stream.seek(position)
             return chunk
         except (AttributeError, OSError):
             raise NotImplementedError("stream is not peekable: %r", stream) from None

 def _make_peekable(stream):
     """return stream as an object with a peek() method"""
     import io
     if hasattr(stream, 'peek'):
         return stream
     if not (hasattr(stream, 'tell') and hasattr(stream, 'seek')):
         try:
             return io.BufferedReader(stream)
         except Exception:
             pass
     return _PeekableReader(stream)

 def _identify_module(file, main=None):
     """identify the name of the module stored in the given file-type object"""
     from pickletools import genops
     UNICODE = {'UNICODE', 'BINUNICODE', 'SHORT_BINUNICODE'}
     found_import = False
     try:
         for opcode, arg, pos in genops(file.peek(256)):
             if not found_import:
                 if opcode.name in ('GLOBAL', 'SHORT_BINUNICODE') and \
                         arg.endswith('_import_module'):
                     found_import = True
             else:
                 if opcode.name in UNICODE:
                     return arg
         else:
             raise UnpicklingError("reached STOP without finding main module")
     except (NotImplementedError, ValueError) as error:
         # ValueError occours when the end of the chunk is reached (without a STOP).
         if isinstance(error, NotImplementedError) and main is not None:
             # file is not peekable, but we have main.
             return None
         raise UnpicklingError("unable to identify main module") from error

 def load_module(
     filename = str(TEMPDIR/'session.pkl'),
     module: Union[ModuleType, str] = None,
     **kwds
 ) -> Optional[ModuleType]:
     """Update the selected module (default is :py:mod:`__main__`) with
     the state saved at ``filename``.

     Restore a module to the state saved with :py:func:`dump_module`. The
     saved module can be :py:mod:`__main__` (e.g. an interpreter session),
     an imported module, or a module-type object (e.g. created with
     :py:class:`~types.ModuleType`).

     When restoring the state of a non-importable module-type object, the
     current instance of this module may be passed as the argument ``main``.
     Otherwise, a new instance is created with :py:class:`~types.ModuleType`
     and returned.

     Parameters:
         filename: a path-like object or a readable stream.
         module: a module object or the name of an importable module;
             the module name and kind (i.e. imported or non-imported) must
             match the name and kind of the module stored at ``filename``.
         **kwds: extra keyword arguments passed to :py:class:`Unpickler()`.

     Raises:
         :py:exc:`UnpicklingError`: if unpickling fails.
         :py:exc:`ValueError`: if the argument ``main`` and module saved
             at ``filename`` are incompatible.

     Returns:
         A module object, if the saved module is not :py:mod:`__main__` or
         a module instance wasn't provided with the argument ``main``.

     Examples:

         - Save the state of some modules:

           >>> import dill
           >>> squared = lambda x: x*x
           >>> dill.dump_module() # save state of __main__ to /tmp/session.pkl
           >>>
           >>> import pox # an imported module
           >>> pox.plus_one = lambda x: x+1
           >>> dill.dump_module('pox_session.pkl', module=pox)
           >>>
           >>> from types import ModuleType
           >>> foo = ModuleType('foo') # a module-type object
           >>> foo.values = [1,2,3]
           >>> import math
           >>> foo.sin = math.sin
           >>> dill.dump_module('foo_session.pkl', module=foo, refimported=True)

         - Restore the state of the interpreter:

           >>> import dill
           >>> dill.load_module() # updates __main__ from /tmp/session.pkl
           >>> squared(2)
           4

         - Load the saved state of an importable module:

           >>> import dill
           >>> pox = dill.load_module('pox_session.pkl')
           >>> pox.plus_one(1)
           2
           >>> import sys
           >>> pox in sys.modules.values()
           True

         - Load the saved state of a non-importable module-type object:

           >>> import dill
           >>> foo = dill.load_module('foo_session.pkl')
           >>> [foo.sin(x) for x in foo.values]
           [0.8414709848078965, 0.9092974268256817, 0.1411200080598672]
           >>> import math
           >>> foo.sin is math.sin # foo.sin was saved by reference
           True
           >>> import sys
           >>> foo in sys.modules.values()
           False

         - Update the state of a non-importable module-type object:

           >>> import dill
           >>> from types import ModuleType
           >>> foo = ModuleType('foo')
           >>> foo.values = ['a','b']
           >>> foo.sin = lambda x: x*x
           >>> dill.load_module('foo_session.pkl', module=foo)
           >>> [foo.sin(x) for x in foo.values]
           [0.8414709848078965, 0.9092974268256817, 0.1411200080598672]

     *Changed in version 0.3.6:* Function ``load_session()`` was renamed to
     ``load_module()``. Parameter ``main`` was renamed to ``module``.

     See also:
         :py:func:`load_module_asdict` to load the contents of module saved
         with :py:func:`dump_module` into a dictionary.
     """
     if 'main' in kwds:
         warnings.warn(
             "The argument 'main' has been renamed 'module'.",
             PendingDeprecationWarning
         )
         if module is not None:
             raise TypeError("both 'module' and 'main' arguments were used")
         module = kwds.pop('main')
     main = module
     if hasattr(filename, 'read'):
         file = filename
     else:
         file = open(filename, 'rb')
     try:
         file = _make_peekable(file)
         #FIXME: dill.settings are disabled
         unpickler = Unpickler(file, **kwds)
         unpickler._session = True

         # Resolve unpickler._main
         pickle_main = _identify_module(file, main)
         if main is None and pickle_main is not None:
             main = pickle_main
         if isinstance(main, str):
             if main.startswith('__runtime__.'):
                 # Create runtime module to load the session into.
                 main = ModuleType(main.partition('.')[-1])
             else:
                 main = _import_module(main)
         if main is not None:
             if not isinstance(main, ModuleType):
                 raise TypeError("%r is not a module" % main)
             unpickler._main = main
         else:
             main = unpickler._main

         # Check against the pickle's main.
         is_main_imported = _is_imported_module(main)
         if pickle_main is not None:
             is_runtime_mod = pickle_main.startswith('__runtime__.')
             if is_runtime_mod:
                 pickle_main = pickle_main.partition('.')[-1]
             error_msg = "can't update{} module{} %r with the saved state of{} module{} %r"
             if is_runtime_mod and is_main_imported:
                 raise ValueError(
                     error_msg.format(" imported", "", "", "-type object")
                     % (main.__name__, pickle_main)
                 )
             if not is_runtime_mod and not is_main_imported:
                 raise ValueError(
                     error_msg.format("", "-type object", " imported", "")
                     % (pickle_main, main.__name__)
                 )
             if main.__name__ != pickle_main:
                 raise ValueError(error_msg.format("", "", "", "") % (main.__name__, pickle_main))

         # This is for find_class() to be able to locate it.
         if not is_main_imported:
             runtime_main = '__runtime__.%s' % main.__name__
             sys.modules[runtime_main] = main

         loaded = unpickler.load()
     finally:
         if not hasattr(filename, 'read'):  # if newly opened file
             file.close()
         try:
             del sys.modules[runtime_main]
         except (KeyError, NameError):
             pass
     assert loaded is main
     _restore_modules(unpickler, main)
     if main is _main_module or main is module:
         return None
     else:
         return main

 # Backward compatibility.
 def load_session(filename=str(TEMPDIR/'session.pkl'), main=None, **kwds):
     warnings.warn("load_session() has been renamed load_module().", PendingDeprecationWarning)
     load_module(filename, module=main, **kwds)
 load_session.__doc__ = load_module.__doc__

 def load_module_asdict(
     filename = str(TEMPDIR/'session.pkl'),
     update: bool = False,
     **kwds
 ) -> dict:
     """
     Load the contents of a saved module into a dictionary.

     ``load_module_asdict()`` is the near-equivalent of::

         lambda filename: vars(dill.load_module(filename)).copy()

     however, does not alter the original module. Also, the path of
     the loaded module is stored in the ``__session__`` attribute.

     Parameters:
         filename: a path-like object or a readable stream
         update: if `True`, initialize the dictionary with the current state
             of the module prior to loading the state stored at filename.
         **kwds: extra keyword arguments passed to :py:class:`Unpickler()`

     Raises:
         :py:exc:`UnpicklingError`: if unpickling fails

     Returns:
         A copy of the restored module's dictionary.

     Note:
         If ``update`` is True, the corresponding module may first be imported
         into the current namespace before the saved state is loaded from
         filename to the dictionary. Note that any module that is imported into
         the current namespace as a side-effect of using ``update`` will not be
         modified by loading the saved module in filename to a dictionary.

     Example:
         >>> import dill
         >>> alist = [1, 2, 3]
         >>> anum = 42
         >>> dill.dump_module()
         >>> anum = 0
         >>> new_var = 'spam'
         >>> main = dill.load_module_asdict()
         >>> main['__name__'], main['__session__']
         ('__main__', '/tmp/session.pkl')
         >>> main is globals() # loaded objects don't reference globals
         False
         >>> main['alist'] == alist
         True
         >>> main['alist'] is alist # was saved by value
         False
         >>> main['anum'] == anum # changed after the session was saved
         False
         >>> new_var in main # would be True if the option 'update' was set
         False
     """
     if 'module' in kwds:
         raise TypeError("'module' is an invalid keyword argument for load_module_asdict()")
     if hasattr(filename, 'read'):
         file = filename
     else:
         file = open(filename, 'rb')
     try:
         file = _make_peekable(file)
         main_name = _identify_module(file)
         old_main = sys.modules.get(main_name)
         main = ModuleType(main_name)
         if update:
             if old_main is None:
                 old_main = _import_module(main_name)
             main.__dict__.update(old_main.__dict__)
         else:
             main.__builtins__ = __builtin__
         sys.modules[main_name] = main
         load_module(file, **kwds)
     finally:
         if not hasattr(filename, 'read'):  # if newly opened file
             file.close()
         try:
             if old_main is None:
                 del sys.modules[main_name]
             else:
                 sys.modules[main_name] = old_main
         except NameError:  # failed before setting old_main
             pass
     main.__session__ = str(filename)
     return main.__dict__


 # Internal exports for backward compatibility with dill v0.3.5.1
 # Can't be placed in dill._dill because of circular import problems.
 for name in (
     '_lookup_module', '_module_map', '_restore_modules', '_stash_modules',
     'dump_session', 'load_session' # backward compatibility functions
 ):
     setattr(_dill, name, globals()[name])
 del name
	#!/usr/bin/env python
	#
	# Author: Mike McKerns (mmckerns @caltech and @uqfoundation)
	# Author: Leonardo Gama (@leogama)
	# Copyright (c) 2008-2015 California Institute of Technology.
	# Copyright (c) 2016-2022 The Uncertainty Quantification Foundation.
	# License: 3-clause BSD. The full license text is available at:
	# - https://github.com/uqfoundation/dill/blob/master/LICENSE
	"""
	Pickle and restore the intepreter session.
	"""

	__all__ = [
	'dump_module', 'load_module', 'load_module_asdict',
	'dump_session', 'load_session' # backward compatibility
	]

	import re
	import sys
	import warnings

	from dill import _dill, Pickler, Unpickler
	from ._dill import (
	BuiltinMethodType, FunctionType, MethodType, ModuleType, TypeType,
	_import_module, _is_builtin_module, _is_imported_module, _main_module,
	_reverse_typemap, __builtin__,
	)

	# Type hints.
	from typing import Optional, Union

	import pathlib
	import tempfile

	TEMPDIR = pathlib.PurePath(tempfile.gettempdir())

	def _module_map():
	"""get map of imported modules"""
	from collections import defaultdict
	from types import SimpleNamespace
	modmap = SimpleNamespace(
	by_name=defaultdict(list),
	by_id=defaultdict(list),
	top_level={},
	)
	for modname, module in sys.modules.items():
	if modname in ('__main__', '__mp_main__') or not isinstance(module, ModuleType):
	continue
	if '.' not in modname:
	modmap.top_level[id(module)] = modname
	for objname, modobj in module.__dict__.items():
	modmap.by_name[objname].append((modobj, modname))
	modmap.by_id[id(modobj)].append((modobj, objname, modname))
	return modmap

	IMPORTED_AS_TYPES = (ModuleType, TypeType, FunctionType, MethodType, BuiltinMethodType)
	if 'PyCapsuleType' in _reverse_typemap:
	IMPORTED_AS_TYPES += (_reverse_typemap['PyCapsuleType'],)
	IMPORTED_AS_MODULES = ('ctypes', 'typing', 'subprocess', 'threading',
	r'concurrent\.futures(\.\w+)?', r'multiprocessing(\.\w+)?')
	IMPORTED_AS_MODULES = tuple(re.compile(x) for x in IMPORTED_AS_MODULES)

	def _lookup_module(modmap, name, obj, main_module):
	"""lookup name or id of obj if module is imported"""
	for modobj, modname in modmap.by_name[name]:
	if modobj is obj and sys.modules[modname] is not main_module:
	return modname, name
	__module__ = getattr(obj, '__module__', None)
	if isinstance(obj, IMPORTED_AS_TYPES) or (__module__ is not None
	and any(regex.fullmatch(__module__) for regex in IMPORTED_AS_MODULES)):
	for modobj, objname, modname in modmap.by_id[id(obj)]:
	if sys.modules[modname] is not main_module:
	return modname, objname
	return None, None

	def _stash_modules(main_module):
	modmap = _module_map()
	newmod = ModuleType(main_module.__name__)

	imported = []
	imported_as = []
	imported_top_level = [] # keep separated for backward compatibility
	original = {}
	for name, obj in main_module.__dict__.items():
	if obj is main_module:
	original[name] = newmod # self-reference
	elif obj is main_module.__dict__:
	original[name] = newmod.__dict__
	# Avoid incorrectly matching a singleton value in another package (ex.: __doc__).
	elif any(obj is singleton for singleton in (None, False, True)) \
	or isinstance(obj, ModuleType) and _is_builtin_module(obj): # always saved by ref
	original[name] = obj
	else:
	source_module, objname = _lookup_module(modmap, name, obj, main_module)
	if source_module is not None:
	if objname == name:
	imported.append((source_module, name))
	else:
	imported_as.append((source_module, objname, name))
	else:
	try:
	imported_top_level.append((modmap.top_level[id(obj)], name))
	except KeyError:
	original[name] = obj

	if len(original) < len(main_module.__dict__):
	newmod.__dict__.update(original)
	newmod.__dill_imported = imported
	newmod.__dill_imported_as = imported_as
	newmod.__dill_imported_top_level = imported_top_level
	if getattr(newmod, '__loader__', None) is None and _is_imported_module(main_module):
	# Trick _is_imported_module() to force saving as an imported module.
	newmod.__loader__ = True # will be discarded by save_module()
	return newmod
	else:
	return main_module

	def _restore_modules(unpickler, main_module):
	try:
	for modname, name in main_module.__dict__.pop('__dill_imported'):
	main_module.__dict__[name] = unpickler.find_class(modname, name)
	for modname, objname, name in main_module.__dict__.pop('__dill_imported_as'):
	main_module.__dict__[name] = unpickler.find_class(modname, objname)
	for modname, name in main_module.__dict__.pop('__dill_imported_top_level'):
	main_module.__dict__[name] = __import__(modname)
	except KeyError:
	pass

	#NOTE: 06/03/15 renamed main_module to main
	def dump_module(
	filename = str(TEMPDIR/'session.pkl'),
	module: Optional[Union[ModuleType, str]] = None,
	refimported: bool = False,
	**kwds
	) -> None:
	"""Pickle the current state of :py:mod:`__main__` or another module to a file.

	Save the contents of :py:mod:`__main__` (e.g. from an interactive
	interpreter session), an imported module, or a module-type object (e.g.
	built with :py:class:`~types.ModuleType`), to a file. The pickled
	module can then be restored with the function :py:func:`load_module`.

	Parameters:
	filename: a path-like object or a writable stream.
	module: a module object or the name of an importable module. If `None`
	(the default), :py:mod:`__main__` is saved.
	refimported: if `True`, all objects identified as having been imported
	into the module's namespace are saved by reference. Note: this is
	similar but independent from ``dill.settings[`byref`]``, as
	``refimported`` refers to virtually all imported objects, while
	``byref`` only affects select objects.
	**kwds: extra keyword arguments passed to :py:class:`Pickler()`.

	Raises:
	:py:exc:`PicklingError`: if pickling fails.

	Examples:

	- Save current interpreter session state:

	>>> import dill
	>>> squared = lambda x: x*x
	>>> dill.dump_module() # save state of __main__ to /tmp/session.pkl

	- Save the state of an imported/importable module:

	>>> import dill
	>>> import pox
	>>> pox.plus_one = lambda x: x+1
	>>> dill.dump_module('pox_session.pkl', module=pox)

	- Save the state of a non-importable, module-type object:

	>>> import dill
	>>> from types import ModuleType
	>>> foo = ModuleType('foo')
	>>> foo.values = [1,2,3]
	>>> import math
	>>> foo.sin = math.sin
	>>> dill.dump_module('foo_session.pkl', module=foo, refimported=True)

	- Restore the state of the saved modules:

	>>> import dill
	>>> dill.load_module()
	>>> squared(2)
	4
	>>> pox = dill.load_module('pox_session.pkl')
	>>> pox.plus_one(1)
	2
	>>> foo = dill.load_module('foo_session.pkl')
	>>> [foo.sin(x) for x in foo.values]
	[0.8414709848078965, 0.9092974268256817, 0.1411200080598672]

	Changed in version 0.3.6: Function ``dump_session()`` was renamed to
	``dump_module()``. Parameters ``main`` and ``byref`` were renamed to
	``module`` and ``refimported``, respectively.

	Note:
	Currently, ``dill.settings['byref']`` and ``dill.settings['recurse']``
	don't apply to this function.`
	"""
	for old_par, par in [('main', 'module'), ('byref', 'refimported')]:
	if old_par in kwds:
	message = "The argument %r has been renamed %r" % (old_par, par)
	if old_par == 'byref':
	message += " to distinguish it from dill.settings['byref']"
	warnings.warn(message + ".", PendingDeprecationWarning)
	if locals()[par]: # the defaults are None and False
	raise TypeError("both %r and %r arguments were used" % (par, old_par))
	refimported = kwds.pop('byref', refimported)
	module = kwds.pop('main', module)

	from .settings import settings
	protocol = settings['protocol']
	main = module
	if main is None:
	main = _main_module
	elif isinstance(main, str):
	main = _import_module(main)
	if not isinstance(main, ModuleType):
	raise TypeError("%r is not a module" % main)
	if hasattr(filename, 'write'):
	file = filename
	else:
	file = open(filename, 'wb')
	try:
	pickler = Pickler(file, protocol, **kwds)
	pickler._original_main = main
	if refimported:
	main = _stash_modules(main)
	pickler._main = main #FIXME: dill.settings are disabled
	pickler._byref = False # disable pickling by name reference
	pickler._recurse = False # disable pickling recursion for globals
	pickler._session = True # is best indicator of when pickling a session
	pickler._first_pass = True
	pickler._main_modified = main is not pickler._original_main
	pickler.dump(main)
	finally:
	if file is not filename: # if newly opened file
	file.close()
	return

	# Backward compatibility.
	def dump_session(filename=str(TEMPDIR/'session.pkl'), main=None, byref=False, **kwds):
	warnings.warn("dump_session() has been renamed dump_module()", PendingDeprecationWarning)
	dump_module(filename, module=main, refimported=byref, **kwds)
	dump_session.__doc__ = dump_module.__doc__

	class _PeekableReader:
	"""lightweight stream wrapper that implements peek()"""
	def __init__(self, stream):
	self.stream = stream
	def read(self, n):
	return self.stream.read(n)
	def readline(self):
	return self.stream.readline()
	def tell(self):
	return self.stream.tell()
	def close(self):
	return self.stream.close()
	def peek(self, n):
	stream = self.stream
	try:
	if hasattr(stream, 'flush'): stream.flush()
	position = stream.tell()
	stream.seek(position) # assert seek() works before reading
	chunk = stream.read(n)
	stream.seek(position)
	return chunk
	except (AttributeError, OSError):
	raise NotImplementedError("stream is not peekable: %r", stream) from None

	def _make_peekable(stream):
	"""return stream as an object with a peek() method"""
	import io
	if hasattr(stream, 'peek'):
	return stream
	if not (hasattr(stream, 'tell') and hasattr(stream, 'seek')):
	try:
	return io.BufferedReader(stream)
	except Exception:
	pass
	return _PeekableReader(stream)

	def _identify_module(file, main=None):
	"""identify the name of the module stored in the given file-type object"""
	from pickletools import genops
	UNICODE = {'UNICODE', 'BINUNICODE', 'SHORT_BINUNICODE'}
	found_import = False
	try:
	for opcode, arg, pos in genops(file.peek(256)):
	if not found_import:
	if opcode.name in ('GLOBAL', 'SHORT_BINUNICODE') and \
	arg.endswith('_import_module'):
	found_import = True
	else:
	if opcode.name in UNICODE:
	return arg
	else:
	raise UnpicklingError("reached STOP without finding main module")
	except (NotImplementedError, ValueError) as error:
	# ValueError occours when the end of the chunk is reached (without a STOP).
	if isinstance(error, NotImplementedError) and main is not None:
	# file is not peekable, but we have main.
	return None
	raise UnpicklingError("unable to identify main module") from error

	def load_module(
	filename = str(TEMPDIR/'session.pkl'),
	module: Union[ModuleType, str] = None,
	**kwds
	) -> Optional[ModuleType]:
	"""Update the selected module (default is :py:mod:`__main__`) with
	the state saved at ``filename``.

	Restore a module to the state saved with :py:func:`dump_module`. The
	saved module can be :py:mod:`__main__` (e.g. an interpreter session),
	an imported module, or a module-type object (e.g. created with
	:py:class:`~types.ModuleType`).

	When restoring the state of a non-importable module-type object, the
	current instance of this module may be passed as the argument ``main``.
	Otherwise, a new instance is created with :py:class:`~types.ModuleType`
	and returned.

	Parameters:
	filename: a path-like object or a readable stream.
	module: a module object or the name of an importable module;
	the module name and kind (i.e. imported or non-imported) must
	match the name and kind of the module stored at ``filename``.
	**kwds: extra keyword arguments passed to :py:class:`Unpickler()`.

	Raises:
	:py:exc:`UnpicklingError`: if unpickling fails.
	:py:exc:`ValueError`: if the argument ``main`` and module saved
	at ``filename`` are incompatible.

	Returns:
	A module object, if the saved module is not :py:mod:`__main__` or
	a module instance wasn't provided with the argument ``main``.

	Examples:

	- Save the state of some modules:

	>>> import dill
	>>> squared = lambda x: x*x
	>>> dill.dump_module() # save state of __main__ to /tmp/session.pkl
	>>>
	>>> import pox # an imported module
	>>> pox.plus_one = lambda x: x+1
	>>> dill.dump_module('pox_session.pkl', module=pox)
	>>>
	>>> from types import ModuleType
	>>> foo = ModuleType('foo') # a module-type object
	>>> foo.values = [1,2,3]
	>>> import math
	>>> foo.sin = math.sin
	>>> dill.dump_module('foo_session.pkl', module=foo, refimported=True)

	- Restore the state of the interpreter:

	>>> import dill
	>>> dill.load_module() # updates __main__ from /tmp/session.pkl
	>>> squared(2)
	4

	- Load the saved state of an importable module:

	>>> import dill
	>>> pox = dill.load_module('pox_session.pkl')
	>>> pox.plus_one(1)
	2
	>>> import sys
	>>> pox in sys.modules.values()
	True

	- Load the saved state of a non-importable module-type object:

	>>> import dill
	>>> foo = dill.load_module('foo_session.pkl')
	>>> [foo.sin(x) for x in foo.values]
	[0.8414709848078965, 0.9092974268256817, 0.1411200080598672]
	>>> import math
	>>> foo.sin is math.sin # foo.sin was saved by reference
	True
	>>> import sys
	>>> foo in sys.modules.values()
	False

	- Update the state of a non-importable module-type object:

	>>> import dill
	>>> from types import ModuleType
	>>> foo = ModuleType('foo')
	>>> foo.values = ['a','b']
	>>> foo.sin = lambda x: x*x
	>>> dill.load_module('foo_session.pkl', module=foo)
	>>> [foo.sin(x) for x in foo.values]
	[0.8414709848078965, 0.9092974268256817, 0.1411200080598672]

	Changed in version 0.3.6: Function ``load_session()`` was renamed to
	``load_module()``. Parameter ``main`` was renamed to ``module``.

	See also:
	:py:func:`load_module_asdict` to load the contents of module saved
	with :py:func:`dump_module` into a dictionary.
	"""
	if 'main' in kwds:
	warnings.warn(
	"The argument 'main' has been renamed 'module'.",
	PendingDeprecationWarning
	)
	if module is not None:
	raise TypeError("both 'module' and 'main' arguments were used")
	module = kwds.pop('main')
	main = module
	if hasattr(filename, 'read'):
	file = filename
	else:
	file = open(filename, 'rb')
	try:
	file = _make_peekable(file)
	#FIXME: dill.settings are disabled
	unpickler = Unpickler(file, **kwds)
	unpickler._session = True

	# Resolve unpickler._main
	pickle_main = _identify_module(file, main)
	if main is None and pickle_main is not None:
	main = pickle_main
	if isinstance(main, str):
	if main.startswith('__runtime__.'):
	# Create runtime module to load the session into.
	main = ModuleType(main.partition('.')[-1])
	else:
	main = _import_module(main)
	if main is not None:
	if not isinstance(main, ModuleType):
	raise TypeError("%r is not a module" % main)
	unpickler._main = main
	else:
	main = unpickler._main

	# Check against the pickle's main.
	is_main_imported = _is_imported_module(main)
	if pickle_main is not None:
	is_runtime_mod = pickle_main.startswith('__runtime__.')
	if is_runtime_mod:
	pickle_main = pickle_main.partition('.')[-1]
	error_msg = "can't update{} module{} %r with the saved state of{} module{} %r"
	if is_runtime_mod and is_main_imported:
	raise ValueError(
	error_msg.format(" imported", "", "", "-type object")
	% (main.__name__, pickle_main)
	)
	if not is_runtime_mod and not is_main_imported:
	raise ValueError(
	error_msg.format("", "-type object", " imported", "")
	% (pickle_main, main.__name__)
	)
	if main.__name__ != pickle_main:
	raise ValueError(error_msg.format("", "", "", "") % (main.__name__, pickle_main))

	# This is for find_class() to be able to locate it.
	if not is_main_imported:
	runtime_main = '__runtime__.%s' % main.__name__
	sys.modules[runtime_main] = main

	loaded = unpickler.load()
	finally:
	if not hasattr(filename, 'read'): # if newly opened file
	file.close()
	try:
	del sys.modules[runtime_main]
	except (KeyError, NameError):
	pass
	assert loaded is main
	_restore_modules(unpickler, main)
	if main is _main_module or main is module:
	return None
	else:
	return main

	# Backward compatibility.
	def load_session(filename=str(TEMPDIR/'session.pkl'), main=None, **kwds):
	warnings.warn("load_session() has been renamed load_module().", PendingDeprecationWarning)
	load_module(filename, module=main, **kwds)
	load_session.__doc__ = load_module.__doc__

	def load_module_asdict(
	filename = str(TEMPDIR/'session.pkl'),
	update: bool = False,
	**kwds
	) -> dict:
	"""
	Load the contents of a saved module into a dictionary.

	``load_module_asdict()`` is the near-equivalent of::

	lambda filename: vars(dill.load_module(filename)).copy()

	however, does not alter the original module. Also, the path of
	the loaded module is stored in the ``__session__`` attribute.

	Parameters:
	filename: a path-like object or a readable stream
	update: if `True`, initialize the dictionary with the current state
	of the module prior to loading the state stored at filename.
	**kwds: extra keyword arguments passed to :py:class:`Unpickler()`

	Raises:
	:py:exc:`UnpicklingError`: if unpickling fails

	Returns:
	A copy of the restored module's dictionary.

	Note:
	If ``update`` is True, the corresponding module may first be imported
	into the current namespace before the saved state is loaded from
	filename to the dictionary. Note that any module that is imported into
	the current namespace as a side-effect of using ``update`` will not be
	modified by loading the saved module in filename to a dictionary.

	Example:
	>>> import dill
	>>> alist = [1, 2, 3]
	>>> anum = 42
	>>> dill.dump_module()
	>>> anum = 0
	>>> new_var = 'spam'
	>>> main = dill.load_module_asdict()
	>>> main['__name__'], main['__session__']
	('__main__', '/tmp/session.pkl')
	>>> main is globals() # loaded objects don't reference globals
	False
	>>> main['alist'] == alist
	True
	>>> main['alist'] is alist # was saved by value
	False
	>>> main['anum'] == anum # changed after the session was saved
	False
	>>> new_var in main # would be True if the option 'update' was set
	False
	"""
	if 'module' in kwds:
	raise TypeError("'module' is an invalid keyword argument for load_module_asdict()")
	if hasattr(filename, 'read'):
	file = filename
	else:
	file = open(filename, 'rb')
	try:
	file = _make_peekable(file)
	main_name = _identify_module(file)
	old_main = sys.modules.get(main_name)
	main = ModuleType(main_name)
	if update:
	if old_main is None:
	old_main = _import_module(main_name)
	main.__dict__.update(old_main.__dict__)
	else:
	main.__builtins__ = __builtin__
	sys.modules[main_name] = main
	load_module(file, **kwds)
	finally:
	if not hasattr(filename, 'read'): # if newly opened file
	file.close()
	try:
	if old_main is None:
	del sys.modules[main_name]
	else:
	sys.modules[main_name] = old_main
	except NameError: # failed before setting old_main
	pass
	main.__session__ = str(filename)
	return main.__dict__


	# Internal exports for backward compatibility with dill v0.3.5.1
	# Can't be placed in dill._dill because of circular import problems.
	for name in (
	'_lookup_module', '_module_map', '_restore_modules', '_stash_modules',
	'dump_session', 'load_session' # backward compatibility functions
	):
	setattr(_dill, name, globals()[name])
	del name