#
# Module providing manager classes for dealing
# with shared objects
#
# multiprocessing/managers.py
#
# Copyright (c) 2006-2008, R Oudkerk
# Licensed to PSF under a Contributor Agreement.
#

__all__ = [ 'BaseManager', 'SyncManager', 'BaseProxy', 'Token',
 'SharedMemoryManager' ]

#
# Imports
#

import sys
import threading
import signal
import array
import queue
import time
import os
from os import getpid

from traceback import format_exc

from . import connection
from .context import reduction, get_spawning_popen, ProcessError
from . import pool
from . import process
from . import util
from . import get_context
try:
 from . import shared_memory
 HAS_SHMEM = True
except ImportError:
 HAS_SHMEM = False

#
# Register some things for pickling
#

def reduce_array(a):
 return array.array, (a.typecode, a.tobytes())
reduction.register(array.array, reduce_array)

view_types = [type(getattr({}, name)()) for name in ('items','keys','values')]
if view_types[0] is not list: # only needed in Py3.0
 def rebuild_as_list(obj):
 return list, (list(obj),)
 for view_type in view_types:
 reduction.register(view_type, rebuild_as_list)

#
# Type for identifying shared objects
#

class Token(object):
 '''
 Type to uniquely indentify a shared object
 '''
 __slots__ = ('typeid', 'address', 'id')

 def __init__(self, typeid, address, id):
 (self.typeid, self.address, self.id) = (typeid, address, id)

 def __getstate__(self):
 return (self.typeid, self.address, self.id)

 def __setstate__(self, state):
 (self.typeid, self.address, self.id) = state

 def __repr__(self):
 return '%s(typeid=%r, address=%r, id=%r)' % \
 (self.__class__.__name__, self.typeid, self.address, self.id)

#
# Function for communication with a manager's server process
#

def dispatch(c, id, methodname, args=(), kwds={}):
 '''
 Send a message to manager using connection `c` and return response
 '''
 c.send((id, methodname, args, kwds))
 kind, result = c.recv()
 if kind == '#RETURN':
 return result
 raise convert_to_error(kind, result)

def convert_to_error(kind, result):
 if kind == '#ERROR':
 return result
 elif kind in ('#TRACEBACK', '#UNSERIALIZABLE'):
 if not isinstance(result, str):
 raise TypeError(
 "Result {0!r} (kind '{1}') type is {2}, not str".format(
 result, kind, type(result)))
 if kind == '#UNSERIALIZABLE':
 return RemoteError('Unserializable message: %s\n' % result)
 else:
 return RemoteError(result)
 else:
 return ValueError('Unrecognized message type {!r}'.format(kind))

class RemoteError(Exception):
 def __str__(self):
 return ('\n' + '-'*75 + '\n' + str(self.args[0]) + '-'*75)

#
# Functions for finding the method names of an object
#

def all_methods(obj):
 '''
 Return a list of names of methods of `obj`
 '''
 temp = []
 for name in dir(obj):
 func = getattr(obj, name)
 if callable(func):
 temp.append(name)
 return temp

def public_methods(obj):
 '''
 Return a list of names of methods of `obj` which do not start with '_'
 '''
 return [name for name in all_methods(obj) if name[0] != '_']

#
# Server which is run in a process controlled by a manager
#

class Server(object):
 '''
 Server class which runs in a process controlled by a manager object
 '''
 public = ['shutdown', 'create', 'accept_connection', 'get_methods',
 'debug_info', 'number_of_objects', 'dummy', 'incref', 'decref']

 def __init__(self, registry, address, authkey, serializer):
 if not isinstance(authkey, bytes):
 raise TypeError(
 "Authkey {0!r} is type {1!s}, not bytes".format(
 authkey, type(authkey)))
 self.registry = registry
 self.authkey = process.AuthenticationString(authkey)
 Listener, Client = listener_client[serializer]

 # do authentication later
 self.listener = Listener(address=address, backlog=16)
 self.address = self.listener.address

 self.id_to_obj = {'0': (None, ())}
 self.id_to_refcount = {}
 self.id_to_local_proxy_obj = {}
 self.mutex = threading.Lock()

 def serve_forever(self):
 '''
 Run the server forever
 '''
 self.stop_event = threading.Event()
 process.current_process()._manager_server = self
 try:
 accepter = threading.Thread(target=self.accepter)
 accepter.daemon = True
 accepter.start()
 try:
 while not self.stop_event.is_set():
 self.stop_event.wait(1)
 except (KeyboardInterrupt, SystemExit):
 pass
 finally:
 if sys.stdout != sys.__stdout__: # what about stderr?
 util.debug('resetting stdout, stderr')
 sys.stdout = sys.__stdout__
 sys.stderr = sys.__stderr__
 sys.exit(0)

 def accepter(self):
 while True:
 try:
 c = self.listener.accept()
 except OSError:
 continue
 t = threading.Thread(target=self.handle_request, args=(c,))
 t.daemon = True
 t.start()

 def handle_request(self, c):
 '''
 Handle a new connection
 '''
 funcname = result = request = None
 try:
 connection.deliver_challenge(c, self.authkey)
 connection.answer_challenge(c, self.authkey)
 request = c.recv()
 ignore, funcname, args, kwds = request
 assert funcname in self.public, '%r unrecognized' % funcname
 func = getattr(self, funcname)
 except Exception:
 msg = ('#TRACEBACK', format_exc())
 else:
 try:
 result = func(c, *args, **kwds)
 except Exception:
 msg = ('#TRACEBACK', format_exc())
 else:
 msg = ('#RETURN', result)
 try:
 c.send(msg)
 except Exception as e:
 try:
 c.send(('#TRACEBACK', format_exc()))
 except Exception:
 pass
 util.info('Failure to send message: %r', msg)
 util.info(' ... request was %r', request)
 util.info(' ... exception was %r', e)

 c.close()

 def serve_client(self, conn):
 '''
 Handle requests from the proxies in a particular process/thread
 '''
 util.debug('starting server thread to service %r',
 threading.current_thread().name)

 recv = conn.recv
 send = conn.send
 id_to_obj = self.id_to_obj

 while not self.stop_event.is_set():

 try:
 methodname = obj = None
 request = recv()
 ident, methodname, args, kwds = request
 try:
 obj, exposed, gettypeid = id_to_obj[ident]
 except KeyError as ke:
 try:
 obj, exposed, gettypeid = \
 self.id_to_local_proxy_obj[ident]
 except KeyError as second_ke:
 raise ke

 if methodname not in exposed:
 raise AttributeError(
 'method %r of %r object is not in exposed=%r' %
 (methodname, type(obj), exposed)
 )

 function = getattr(obj, methodname)

 try:
 res = function(*args, **kwds)
 except Exception as e:
 msg = ('#ERROR', e)
 else:
 typeid = gettypeid and gettypeid.get(methodname, None)
 if typeid:
 rident, rexposed = self.create(conn, typeid, res)
 token = Token(typeid, self.address, rident)
 msg = ('#PROXY', (rexposed, token))
 else:
 msg = ('#RETURN', res)

 except AttributeError:
 if methodname is None:
 msg = ('#TRACEBACK', format_exc())
 else:
 try:
 fallback_func = self.fallback_mapping[methodname]
 result = fallback_func(
 self, conn, ident, obj, *args, **kwds
 )
 msg = ('#RETURN', result)
 except Exception:
 msg = ('#TRACEBACK', format_exc())

 except EOFError:
 util.debug('got EOF -- exiting thread serving %r',
 threading.current_thread().name)
 sys.exit(0)

 except Exception:
 msg = ('#TRACEBACK', format_exc())

 try:
 try:
 send(msg)
 except Exception as e:
 send(('#UNSERIALIZABLE', format_exc()))
 except Exception as e:
 util.info('exception in thread serving %r',
 threading.current_thread().name)
 util.info(' ... message was %r', msg)
 util.info(' ... exception was %r', e)
 conn.close()
 sys.exit(1)

 def fallback_getvalue(self, conn, ident, obj):
 return obj

 def fallback_str(self, conn, ident, obj):
 return str(obj)

 def fallback_repr(self, conn, ident, obj):
 return repr(obj)

 fallback_mapping = {
 '__str__':fallback_str,
 '__repr__':fallback_repr,
 '#GETVALUE':fallback_getvalue
 }

 def dummy(self, c):
 pass

 def debug_info(self, c):
 '''
 Return some info --- useful to spot problems with refcounting
 '''
 # Perhaps include debug info about 'c'?
 with self.mutex:
 result = []
 keys = list(self.id_to_refcount.keys())
 keys.sort()
 for ident in keys:
 if ident != '0':
 result.append(' %s: refcount=%s\n %s' %
 (ident, self.id_to_refcount[ident],
 str(self.id_to_obj[ident][0])[:75]))
 return '\n'.join(result)

 def number_of_objects(self, c):
 '''
 Number of shared objects
 '''
 # Doesn't use (len(self.id_to_obj) - 1) as we shouldn't count ident='0'
 return len(self.id_to_refcount)

 def shutdown(self, c):
 '''
 Shutdown this process
 '''
 try:
 util.debug('manager received shutdown message')
 c.send(('#RETURN', None))
 except:
 import traceback
 traceback.print_exc()
 finally:
 self.stop_event.set()

 def create(*args, **kwds):
 '''
 Create a new shared object and return its id
 '''
 if len(args) >= 3:
 self, c, typeid, *args = args
 elif not args:
 raise TypeError("descriptor 'create' of 'Server' object "
 "needs an argument")
 else:
 if 'typeid' not in kwds:
 raise TypeError('create expected at least 2 positional '
 'arguments, got %d' % (len(args)-1))
 typeid = kwds.pop('typeid')
 if len(args) >= 2:
 self, c, *args = args
 import warnings
 warnings.warn("Passing 'typeid' as keyword argument is deprecated",
 DeprecationWarning, stacklevel=2)
 else:
 if 'c' not in kwds:
 raise TypeError('create expected at least 2 positional '
 'arguments, got %d' % (len(args)-1))
 c = kwds.pop('c')
 self, *args = args
 import warnings
 warnings.warn("Passing 'c' as keyword argument is deprecated",
 DeprecationWarning, stacklevel=2)
 args = tuple(args)

 with self.mutex:
 callable, exposed, method_to_typeid, proxytype = \
 self.registry[typeid]

 if callable is None:
 if kwds or (len(args) != 1):
 raise ValueError(
 "Without callable, must have one non-keyword argument")
 obj = args[0]
 else:
 obj = callable(*args, **kwds)

 if exposed is None:
 exposed = public_methods(obj)
 if method_to_typeid is not None:
 if not isinstance(method_to_typeid, dict):
 raise TypeError(
 "Method_to_typeid {0!r}: type {1!s}, not dict".format(
 method_to_typeid, type(method_to_typeid)))
 exposed = list(exposed) + list(method_to_typeid)

 ident = '%x' % id(obj) # convert to string because xmlrpclib
 # only has 32 bit signed integers
 util.debug('%r callable returned object with id %r', typeid, ident)

 self.id_to_obj[ident] = (obj, set(exposed), method_to_typeid)
 if ident not in self.id_to_refcount:
 self.id_to_refcount[ident] = 0

 self.incref(c, ident)
 return ident, tuple(exposed)
 create.__text_signature__ = '($self, c, typeid, /, *args, **kwds)'

 def get_methods(self, c, token):
 '''
 Return the methods of the shared object indicated by token
 '''
 return tuple(self.id_to_obj[token.id][1])

 def accept_connection(self, c, name):
 '''
 Spawn a new thread to serve this connection
 '''
 threading.current_thread().name = name
 c.send(('#RETURN', None))
 self.serve_client(c)

 def incref(self, c, ident):
 with self.mutex:
 try:
 self.id_to_refcount[ident] += 1
 except KeyError as ke:
 # If no external references exist but an internal (to the
 # manager) still does and a new external reference is created
 # from it, restore the manager's tracking of it from the
 # previously stashed internal ref.
 if ident in self.id_to_local_proxy_obj:
 self.id_to_refcount[ident] = 1
 self.id_to_obj[ident] = \
 self.id_to_local_proxy_obj[ident]
 obj, exposed, gettypeid = self.id_to_obj[ident]
 util.debug('Server re-enabled tracking & INCREF %r', ident)
 else:
 raise ke

 def decref(self, c, ident):
 if ident not in self.id_to_refcount and \
 ident in self.id_to_local_proxy_obj:
 util.debug('Server DECREF skipping %r', ident)
 return

 with self.mutex:
 if self.id_to_refcount[ident] <= 0:
 raise AssertionError(
 "Id {0!s} ({1!r}) has refcount {2:n}, not 1+".format(
 ident, self.id_to_obj[ident],
 self.id_to_refcount[ident]))
 self.id_to_refcount[ident] -= 1
 if self.id_to_refcount[ident] == 0:
 del self.id_to_refcount[ident]

 if ident not in self.id_to_refcount:
 # Two-step process in case the object turns out to contain other
 # proxy objects (e.g. a managed list of managed lists).
 # Otherwise, deleting self.id_to_obj[ident] would trigger the
 # deleting of the stored value (another managed object) which would
 # in turn attempt to acquire the mutex that is already held here.
 self.id_to_obj[ident] = (None, (), None) # thread-safe
 util.debug('disposing of obj with id %r', ident)
 with self.mutex:
 del self.id_to_obj[ident]


#
# Class to represent state of a manager
#

class State(object):
 __slots__ = ['value']
 INITIAL = 0
 STARTED = 1
 SHUTDOWN = 2

#
# Mapping from serializer name to Listener and Client types
#

listener_client = {
 'pickle' : (connection.Listener, connection.Client),
 'xmlrpclib' : (connection.XmlListener, connection.XmlClient)
 }

#
# Definition of BaseManager
#

class BaseManager(object):
 '''
 Base class for managers
 '''
 _registry = {}
 _Server = Server

 def __init__(self, address=None, authkey=None, serializer='pickle',
 ctx=None):
 if authkey is None:
 authkey = process.current_process().authkey
 self._address = address # XXX not final address if eg ('', 0)
 self._authkey = process.AuthenticationString(authkey)
 self._state = State()
 self._state.value = State.INITIAL
 self._serializer = serializer
 self._Listener, self._Client = listener_client[serializer]
 self._ctx = ctx or get_context()

 def get_server(self):
 '''
 Return server object with serve_forever() method and address attribute
 '''
 if self._state.value != State.INITIAL:
 if self._state.value == State.STARTED:
 raise ProcessError("Already started server")
 elif self._state.value == State.SHUTDOWN:
 raise ProcessError("Manager has shut down")
 else:
 raise ProcessError(
 "Unknown state {!r}".format(self._state.value))
 return Server(self._registry, self._address,
 self._authkey, self._serializer)

 def connect(self):
 '''
 Connect manager object to the server process
 '''
 Listener, Client = listener_client[self._serializer]
 conn = Client(self._address, authkey=self._authkey)
 dispatch(conn, None, 'dummy')
 self._state.value = State.STARTED

 def start(self, initializer=None, initargs=()):
 '''
 Spawn a server process for this manager object
 '''
 if self._state.value != State.INITIAL:
 if self._state.value == State.STARTED:
 raise ProcessError("Already started server")
 elif self._state.value == State.SHUTDOWN:
 raise ProcessError("Manager has shut down")
 else:
 raise ProcessError(
 "Unknown state {!r}".format(self._state.value))

 if initializer is not None and not callable(initializer):
 raise TypeError('initializer must be a callable')

 # pipe over which we will retrieve address of server
 reader, writer = connection.Pipe(duplex=False)

 # spawn process which runs a server
 self._process = self._ctx.Process(
 target=type(self)._run_server,
 args=(self._registry, self._address, self._authkey,
 self._serializer, writer, initializer, initargs),
 )
 ident = ':'.join(str(i) for i in self._process._identity)
 self._process.name = type(self).__name__ + '-' + ident
 self._process.start()

 # get address of server
 writer.close()
 self._address = reader.recv()
 reader.close()

 # register a finalizer
 self._state.value = State.STARTED
 self.shutdown = util.Finalize(
 self, type(self)._finalize_manager,
 args=(self._process, self._address, self._authkey,
 self._state, self._Client),
 exitpriority=0
 )

 @classmethod
 def _run_server(cls, registry, address, authkey, serializer, writer,
 initializer=None, initargs=()):
 '''
 Create a server, report its address and run it
 '''
 # bpo-36368: protect server process from KeyboardInterrupt signals
 signal.signal(signal.SIGINT, signal.SIG_IGN)

 if initializer is not None:
 initializer(*initargs)

 # create server
 server = cls._Server(registry, address, authkey, serializer)

 # inform parent process of the server's address
 writer.send(server.address)
 writer.close()

 # run the manager
 util.info('manager serving at %r', server.address)
 server.serve_forever()

 def _create(self, typeid, /, *args, **kwds):
 '''
 Create a new shared object; return the token and exposed tuple
 '''
 assert self._state.value == State.STARTED, 'server not yet started'
 conn = self._Client(self._address, authkey=self._authkey)
 try:
 id, exposed = dispatch(conn, None, 'create', (typeid,)+args, kwds)
 finally:
 conn.close()
 return Token(typeid, self._address, id), exposed

 def join(self, timeout=None):
 '''
 Join the manager process (if it has been spawned)
 '''
 if self._process is not None:
 self._process.join(timeout)
 if not self._process.is_alive():
 self._process = None

 def _debug_info(self):
 '''
 Return some info about the servers shared objects and connections
 '''
 conn = self._Client(self._address, authkey=self._authkey)
 try:
 return dispatch(conn, None, 'debug_info')
 finally:
 conn.close()

 def _number_of_objects(self):
 '''
 Return the number of shared objects
 '''
 conn = self._Client(self._address, authkey=self._authkey)
 try:
 return dispatch(conn, None, 'number_of_objects')
 finally:
 conn.close()

 def __enter__(self):
 if self._state.value == State.INITIAL:
 self.start()
 if self._state.value != State.STARTED:
 if self._state.value == State.INITIAL:
 raise ProcessError("Unable to start server")
 elif self._state.value == State.SHUTDOWN:
 raise ProcessError("Manager has shut down")
 else:
 raise ProcessError(
 "Unknown state {!r}".format(self._state.value))
 return self

 def __exit__(self, exc_type, exc_val, exc_tb):
 self.shutdown()

 @staticmethod
 def _finalize_manager(process, address, authkey, state, _Client):
 '''
 Shutdown the manager process; will be registered as a finalizer
 '''
 if process.is_alive():
 util.info('sending shutdown message to manager')
 try:
 conn = _Client(address, authkey=authkey)
 try:
 dispatch(conn, None, 'shutdown')
 finally:
 conn.close()
 except Exception:
 pass

 process.join(timeout=1.0)
 if process.is_alive():
 util.info('manager still alive')
 if hasattr(process, 'terminate'):
 util.info('trying to `terminate()` manager process')
 process.terminate()
 process.join(timeout=0.1)
 if process.is_alive():
 util.info('manager still alive after terminate')

 state.value = State.SHUTDOWN
 try:
 del BaseProxy._address_to_local[address]
 except KeyError:
 pass

 @property
 def address(self):
 return self._address

 @classmethod
 def register(cls, typeid, callable=None, proxytype=None, exposed=None,
 method_to_typeid=None, create_method=True):
 '''
 Register a typeid with the manager type
 '''
 if '_registry' not in cls.__dict__:
 cls._registry = cls._registry.copy()

 if proxytype is None:
 proxytype = AutoProxy

 exposed = exposed or getattr(proxytype, '_exposed_', None)

 method_to_typeid = method_to_typeid or \
 getattr(proxytype, '_method_to_typeid_', None)

 if method_to_typeid:
 for key, value in list(method_to_typeid.items()): # isinstance?
 assert type(key) is str, '%r is not a string' % key
 assert type(value) is str, '%r is not a string' % value

 cls._registry[typeid] = (
 callable, exposed, method_to_typeid, proxytype
 )

 if create_method:
 def temp(self, /, *args, **kwds):
 util.debug('requesting creation of a shared %r object', typeid)
 token, exp = self._create(typeid, *args, **kwds)
 proxy = proxytype(
 token, self._serializer, manager=self,
 authkey=self._authkey, exposed=exp
 )
 conn = self._Client(token.address, authkey=self._authkey)
 dispatch(conn, None, 'decref', (token.id,))
 return proxy
 temp.__name__ = typeid
 setattr(cls, typeid, temp)

#
# Subclass of set which get cleared after a fork
#

class ProcessLocalSet(set):
 def __init__(self):
 util.register_after_fork(self, lambda obj: obj.clear())
 def __reduce__(self):
 return type(self), ()

#
# Definition of BaseProxy
#

class BaseProxy(object):
 '''
 A base for proxies of shared objects
 '''
 _address_to_local = {}
 _mutex = util.ForkAwareThreadLock()

 def __init__(self, token, serializer, manager=None,
 authkey=None, exposed=None, incref=True, manager_owned=False):
 with BaseProxy._mutex:
 tls_idset = BaseProxy._address_to_local.get(token.address, None)
 if tls_idset is None:
 tls_idset = util.ForkAwareLocal(), ProcessLocalSet()
 BaseProxy._address_to_local[token.address] = tls_idset

 # self._tls is used to record the connection used by this
 # thread to communicate with the manager at token.address
 self._tls = tls_idset[0]

 # self._idset is used to record the identities of all shared
 # objects for which the current process owns references and
 # which are in the manager at token.address
 self._idset = tls_idset[1]

 self._token = token
 self._id = self._token.id
 self._manager = manager
 self._serializer = serializer
 self._Client = listener_client[serializer][1]

 # Should be set to True only when a proxy object is being created
 # on the manager server; primary use case: nested proxy objects.
 # RebuildProxy detects when a proxy is being created on the manager
 # and sets this value appropriately.
 self._owned_by_manager = manager_owned

 if authkey is not None:
 self._authkey = process.AuthenticationString(authkey)
 elif self._manager is not None:
 self._authkey = self._manager._authkey
 else:
 self._authkey = process.current_process().authkey

 if incref:
 self._incref()

 util.register_after_fork(self, BaseProxy._after_fork)

 def _connect(self):
 util.debug('making connection to manager')
 name = process.current_process().name
 if threading.current_thread().name != 'MainThread':
 name += '|' + threading.current_thread().name
 conn = self._Client(self._token.address, authkey=self._authkey)
 dispatch(conn, None, 'accept_connection', (name,))
 self._tls.connection = conn

 def _callmethod(self, methodname, args=(), kwds={}):
 '''
 Try to call a method of the referrent and return a copy of the result
 '''
 try:
 conn = self._tls.connection
 except AttributeError:
 util.debug('thread %r does not own a connection',
 threading.current_thread().name)
 self._connect()
 conn = self._tls.connection

 conn.send((self._id, methodname, args, kwds))
 kind, result = conn.recv()

 if kind == '#RETURN':
 return result
 elif kind == '#PROXY':
 exposed, token = result
 proxytype = self._manager._registry[token.typeid][-1]
 token.address = self._token.address
 proxy = proxytype(
 token, self._serializer, manager=self._manager,
 authkey=self._authkey, exposed=exposed
 )
 conn = self._Client(token.address, authkey=self._authkey)
 dispatch(conn, None, 'decref', (token.id,))
 return proxy
 raise convert_to_error(kind, result)

 def _getvalue(self):
 '''
 Get a copy of the value of the referent
 '''
 return self._callmethod('#GETVALUE')

 def _incref(self):
 if self._owned_by_manager:
 util.debug('owned_by_manager skipped INCREF of %r', self._token.id)
 return

 conn = self._Client(self._token.address, authkey=self._authkey)
 dispatch(conn, None, 'incref', (self._id,))
 util.debug('INCREF %r', self._token.id)

 self._idset.add(self._id)

 state = self._manager and self._manager._state

 self._close = util.Finalize(
 self, BaseProxy._decref,
 args=(self._token, self._authkey, state,
 self._tls, self._idset, self._Client),
 exitpriority=10
 )

 @staticmethod
 def _decref(token, authkey, state, tls, idset, _Client):
 idset.discard(token.id)

 # check whether manager is still alive
 if state is None or state.value == State.STARTED:
 # tell manager this process no longer cares about referent
 try:
 util.debug('DECREF %r', token.id)
 conn = _Client(token.address, authkey=authkey)
 dispatch(conn, None, 'decref', (token.id,))
 except Exception as e:
 util.debug('... decref failed %s', e)

 else:
 util.debug('DECREF %r -- manager already shutdown', token.id)

 # check whether we can close this thread's connection because
 # the process owns no more references to objects for this manager
 if not idset and hasattr(tls, 'connection'):
 util.debug('thread %r has no more proxies so closing conn',
 threading.current_thread().name)
 tls.connection.close()
 del tls.connection

 def _after_fork(self):
 self._manager = None
 try:
 self._incref()
 except Exception as e:
 # the proxy may just be for a manager which has shutdown
 util.info('incref failed: %s' % e)

 def __reduce__(self):
 kwds = {}
 if get_spawning_popen() is not None:
 kwds['authkey'] = self._authkey

 if getattr(self, '_isauto', False):
 kwds['exposed'] = self._exposed_
 return (RebuildProxy,
 (AutoProxy, self._token, self._serializer, kwds))
 else:
 return (RebuildProxy,
 (type(self), self._token, self._serializer, kwds))

 def __deepcopy__(self, memo):
 return self._getvalue()

 def __repr__(self):
 return '<%s object, typeid %r at %#x>' % \
 (type(self).__name__, self._token.typeid, id(self))

 def __str__(self):
 '''
 Return representation of the referent (or a fall-back if that fails)
 '''
 try:
 return self._callmethod('__repr__')
 except Exception:
 return repr(self)[:-1] + "; '__str__()' failed>"

#
# Function used for unpickling
#

def RebuildProxy(func, token, serializer, kwds):
 '''
 Function used for unpickling proxy objects.
 '''
 server = getattr(process.current_process(), '_manager_server', None)
 if server and server.address == token.address:
 util.debug('Rebuild a proxy owned by manager, token=%r', token)
 kwds['manager_owned'] = True
 if token.id not in server.id_to_local_proxy_obj:
 server.id_to_local_proxy_obj[token.id] = \
 server.id_to_obj[token.id]
 incref = (
 kwds.pop('incref', True) and
 not getattr(process.current_process(), '_inheriting', False)
 )
 return func(token, serializer, incref=incref, **kwds)

#
# Functions to create proxies and proxy types
#

def MakeProxyType(name, exposed, _cache={}):
 '''
 Return a proxy type whose methods are given by `exposed`
 '''
 exposed = tuple(exposed)
 try:
 return _cache[(name, exposed)]
 except KeyError:
 pass

 dic = {}

 for meth in exposed:
 exec('''def %s(self, /, *args, **kwds):
 return self._callmethod(%r, args, kwds)''' % (meth, meth), dic)

 ProxyType = type(name, (BaseProxy,), dic)
 ProxyType._exposed_ = exposed
 _cache[(name, exposed)] = ProxyType
 return ProxyType


def AutoProxy(token, serializer, manager=None, authkey=None,
 exposed=None, incref=True):
 '''
 Return an auto-proxy for `token`
 '''
 _Client = listener_client[serializer][1]

 if exposed is None:
 conn = _Client(token.address, authkey=authkey)
 try:
 exposed = dispatch(conn, None, 'get_methods', (token,))
 finally:
 conn.close()

 if authkey is None and manager is not None:
 authkey = manager._authkey
 if authkey is None:
 authkey = process.current_process().authkey

 ProxyType = MakeProxyType('AutoProxy[%s]' % token.typeid, exposed)
 proxy = ProxyType(token, serializer, manager=manager, authkey=authkey,
 incref=incref)
 proxy._isauto = True
 return proxy

#
# Types/callables which we will register with SyncManager
#

class Namespace(object):
 def __init__(self, /, **kwds):
 self.__dict__.update(kwds)
 def __repr__(self):
 items = list(self.__dict__.items())
 temp = []
 for name, value in items:
 if not name.startswith('_'):
 temp.append('%s=%r' % (name, value))
 temp.sort()
 return '%s(%s)' % (self.__class__.__name__, ', '.join(temp))

class Value(object):
 def __init__(self, typecode, value, lock=True):
 self._typecode = typecode
 self._value = value
 def get(self):
 return self._value
 def set(self, value):
 self._value = value
 def __repr__(self):
 return '%s(%r, %r)'%(type(self).__name__, self._typecode, self._value)
 value = property(get, set)

def Array(typecode, sequence, lock=True):
 return array.array(typecode, sequence)

#
# Proxy types used by SyncManager
#

class IteratorProxy(BaseProxy):
 _exposed_ = ('__next__', 'send', 'throw', 'close')
 def __iter__(self):
 return self
 def __next__(self, *args):
 return self._callmethod('__next__', args)
 def send(self, *args):
 return self._callmethod('send', args)
 def throw(self, *args):
 return self._callmethod('throw', args)
 def close(self, *args):
 return self._callmethod('close', args)


class AcquirerProxy(BaseProxy):
 _exposed_ = ('acquire', 'release')
 def acquire(self, blocking=True, timeout=None):
 args = (blocking,) if timeout is None else (blocking, timeout)
 return self._callmethod('acquire', args)
 def release(self):
 return self._callmethod('release')
 def __enter__(self):
 return self._callmethod('acquire')
 def __exit__(self, exc_type, exc_val, exc_tb):
 return self._callmethod('release')


class ConditionProxy(AcquirerProxy):
 _exposed_ = ('acquire', 'release', 'wait', 'notify', 'notify_all')
 def wait(self, timeout=None):
 return self._callmethod('wait', (timeout,))
 def notify(self, n=1):
 return self._callmethod('notify', (n,))
 def notify_all(self):
 return self._callmethod('notify_all')
 def wait_for(self, predicate, timeout=None):
 result = predicate()
 if result:
 return result
 if timeout is not None:
 endtime = time.monotonic() + timeout
 else:
 endtime = None
 waittime = None
 while not result:
 if endtime is not None:
 waittime = endtime - time.monotonic()
 if waittime <= 0:
 break
 self.wait(waittime)
 result = predicate()
 return result


class EventProxy(BaseProxy):
 _exposed_ = ('is_set', 'set', 'clear', 'wait')
 def is_set(self):
 return self._callmethod('is_set')
 def set(self):
 return self._callmethod('set')
 def clear(self):
 return self._callmethod('clear')
 def wait(self, timeout=None):
 return self._callmethod('wait', (timeout,))


class BarrierProxy(BaseProxy):
 _exposed_ = ('__getattribute__', 'wait', 'abort', 'reset')
 def wait(self, timeout=None):
 return self._callmethod('wait', (timeout,))
 def abort(self):
 return self._callmethod('abort')
 def reset(self):
 return self._callmethod('reset')
 @property
 def parties(self):
 return self._callmethod('__getattribute__', ('parties',))
 @property
 def n_waiting(self):
 return self._callmethod('__getattribute__', ('n_waiting',))
 @property
 def broken(self):
 return self._callmethod('__getattribute__', ('broken',))


class NamespaceProxy(BaseProxy):
 _exposed_ = ('__getattribute__', '__setattr__', '__delattr__')
 def __getattr__(self, key):
 if key[0] == '_':
 return object.__getattribute__(self, key)
 callmethod = object.__getattribute__(self, '_callmethod')
 return callmethod('__getattribute__', (key,))
 def __setattr__(self, key, value):
 if key[0] == '_':
 return object.__setattr__(self, key, value)
 callmethod = object.__getattribute__(self, '_callmethod')
 return callmethod('__setattr__', (key, value))
 def __delattr__(self, key):
 if key[0] == '_':
 return object.__delattr__(self, key)
 callmethod = object.__getattribute__(self, '_callmethod')
 return callmethod('__delattr__', (key,))


class ValueProxy(BaseProxy):
 _exposed_ = ('get', 'set')
 def get(self):
 return self._callmethod('get')
 def set(self, value):
 return self._callmethod('set', (value,))
 value = property(get, set)


BaseListProxy = MakeProxyType('BaseListProxy', (
 '__add__', '__contains__', '__delitem__', '__getitem__', '__len__',
 '__mul__', '__reversed__', '__rmul__', '__setitem__',
 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
 'reverse', 'sort', '__imul__'
 ))
class ListProxy(BaseListProxy):
 def __iadd__(self, value):
 self._callmethod('extend', (value,))
 return self
 def __imul__(self, value):
 self._callmethod('__imul__', (value,))
 return self


DictProxy = MakeProxyType('DictProxy', (
 '__contains__', '__delitem__', '__getitem__', '__iter__', '__len__',
 '__setitem__', 'clear', 'copy', 'get', 'items',
 'keys', 'pop', 'popitem', 'setdefault', 'update', 'values'
 ))
DictProxy._method_to_typeid_ = {
 '__iter__': 'Iterator',
 }


ArrayProxy = MakeProxyType('ArrayProxy', (
 '__len__', '__getitem__', '__setitem__'
 ))


BasePoolProxy = MakeProxyType('PoolProxy', (
 'apply', 'apply_async', 'close', 'imap', 'imap_unordered', 'join',
 'map', 'map_async', 'starmap', 'starmap_async', 'terminate',
 ))
BasePoolProxy._method_to_typeid_ = {
 'apply_async': 'AsyncResult',
 'map_async': 'AsyncResult',
 'starmap_async': 'AsyncResult',
 'imap': 'Iterator',
 'imap_unordered': 'Iterator'
 }
class PoolProxy(BasePoolProxy):
 def __enter__(self):
 return self
 def __exit__(self, exc_type, exc_val, exc_tb):
 self.terminate()

#
# Definition of SyncManager
#

class SyncManager(BaseManager):
 '''
 Subclass of `BaseManager` which supports a number of shared object types.

 The types registered are those intended for the synchronization
 of threads, plus `dict`, `list` and `Namespace`.

 The `multiprocessing.Manager()` function creates started instances of
 this class.
 '''

SyncManager.register('Queue', queue.Queue)
SyncManager.register('JoinableQueue', queue.Queue)
SyncManager.register('Event', threading.Event, EventProxy)
SyncManager.register('Lock', threading.Lock, AcquirerProxy)
SyncManager.register('RLock', threading.RLock, AcquirerProxy)
SyncManager.register('Semaphore', threading.Semaphore, AcquirerProxy)
SyncManager.register('BoundedSemaphore', threading.BoundedSemaphore,
 AcquirerProxy)
SyncManager.register('Condition', threading.Condition, ConditionProxy)
SyncManager.register('Barrier', threading.Barrier, BarrierProxy)
SyncManager.register('Pool', pool.Pool, PoolProxy)
SyncManager.register('list', list, ListProxy)
SyncManager.register('dict', dict, DictProxy)
SyncManager.register('Value', Value, ValueProxy)
SyncManager.register('Array', Array, ArrayProxy)
SyncManager.register('Namespace', Namespace, NamespaceProxy)

# types returned by methods of PoolProxy
SyncManager.register('Iterator', proxytype=IteratorProxy, create_method=False)
SyncManager.register('AsyncResult', create_method=False)

#
# Definition of SharedMemoryManager and SharedMemoryServer
#

if HAS_SHMEM:
 class _SharedMemoryTracker:
 "Manages one or more shared memory segments."

 def __init__(self, name, segment_names=[]):
 self.shared_memory_context_name = name
 self.segment_names = segment_names

 def register_segment(self, segment_name):
 "Adds the supplied shared memory block name to tracker."
 util.debug(f"Register segment {segment_name!r} in pid {getpid()}")
 self.segment_names.append(segment_name)

 def destroy_segment(self, segment_name):
 """Calls unlink() on the shared memory block with the supplied name
 and removes it from the list of blocks being tracked."""
 util.debug(f"Destroy segment {segment_name!r} in pid {getpid()}")
 self.segment_names.remove(segment_name)
 segment = shared_memory.SharedMemory(segment_name)
 segment.close()
 segment.unlink()

 def unlink(self):
 "Calls destroy_segment() on all tracked shared memory blocks."
 for segment_name in self.segment_names[:]:
 self.destroy_segment(segment_name)

 def __del__(self):
 util.debug(f"Call {self.__class__.__name__}.__del__ in {getpid()}")
 self.unlink()

 def __getstate__(self):
 return (self.shared_memory_context_name, self.segment_names)

 def __setstate__(self, state):
 self.__init__(*state)


 class SharedMemoryServer(Server):

 public = Server.public + \
 ['track_segment', 'release_segment', 'list_segments']

 def __init__(self, *args, **kwargs):
 Server.__init__(self, *args, **kwargs)
 self.shared_memory_context = \
 _SharedMemoryTracker(f"shmm_{self.address}_{getpid()}")
 util.debug(f"SharedMemoryServer started by pid {getpid()}")

 def create(*args, **kwargs):
 """Create a new distributed-shared object (not backed by a shared
 memory block) and return its id to be used in a Proxy Object."""
 # Unless set up as a shared proxy, don't make shared_memory_context
 # a standard part of kwargs. This makes things easier for supplying
 # simple functions.
 if len(args) >= 3:
 typeod = args[2]
 elif 'typeid' in kwargs:
 typeid = kwargs['typeid']
 elif not args:
 raise TypeError("descriptor 'create' of 'SharedMemoryServer' "
 "object needs an argument")
 else:
 raise TypeError('create expected at least 2 positional '
 'arguments, got %d' % (len(args)-1))
 if hasattr(self.registry[typeid][-1], "_shared_memory_proxy"):
 kwargs['shared_memory_context'] = self.shared_memory_context
 return Server.create(*args, **kwargs)
 create.__text_signature__ = '($self, c, typeid, /, *args, **kwargs)'

 def shutdown(self, c):
 "Call unlink() on all tracked shared memory, terminate the Server."
 self.shared_memory_context.unlink()
 return Server.shutdown(self, c)

 def track_segment(self, c, segment_name):
 "Adds the supplied shared memory block name to Server's tracker."
 self.shared_memory_context.register_segment(segment_name)

 def release_segment(self, c, segment_name):
 """Calls unlink() on the shared memory block with the supplied name
 and removes it from the tracker instance inside the Server."""
 self.shared_memory_context.destroy_segment(segment_name)

 def list_segments(self, c):
 """Returns a list of names of shared memory blocks that the Server
 is currently tracking."""
 return self.shared_memory_context.segment_names


 class SharedMemoryManager(BaseManager):
 """Like SyncManager but uses SharedMemoryServer instead of Server.

 It provides methods for creating and returning SharedMemory instances
 and for creating a list-like object (ShareableList) backed by shared
 memory. It also provides methods that create and return Proxy Objects
 that support synchronization across processes (i.e. multi-process-safe
 locks and semaphores).
 """

 _Server = SharedMemoryServer

 def __init__(self, *args, **kwargs):
 if os.name == "posix":
 # bpo-36867: Ensure the resource_tracker is running before
 # launching the manager process, so that concurrent
 # shared_memory manipulation both in the manager and in the
 # current process does not create two resource_tracker
 # processes.
 from . import resource_tracker
 resource_tracker.ensure_running()
 BaseManager.__init__(self, *args, **kwargs)
 util.debug(f"{self.__class__.__name__} created by pid {getpid()}")

 def __del__(self):
 util.debug(f"{self.__class__.__name__}.__del__ by pid {getpid()}")
 pass

 def get_server(self):
 'Better than monkeypatching for now; merge into Server ultimately'
 if self._state.value != State.INITIAL:
 if self._state.value == State.STARTED:
 raise ProcessError("Already started SharedMemoryServer")
 elif self._state.value == State.SHUTDOWN:
 raise ProcessError("SharedMemoryManager has shut down")
 else:
 raise ProcessError(
 "Unknown state {!r}".format(self._state.value))
 return self._Server(self._registry, self._address,
 self._authkey, self._serializer)

 def SharedMemory(self, size):
 """Returns a new SharedMemory instance with the specified size in
 bytes, to be tracked by the manager."""
 with self._Client(self._address, authkey=self._authkey) as conn:
 sms = shared_memory.SharedMemory(None, create=True, size=size)
 try:
 dispatch(conn, None, 'track_segment', (sms.name,))
 except BaseException as e:
 sms.unlink()
 raise e
 return sms

 def ShareableList(self, sequence):
 """Returns a new ShareableList instance populated with the values
 from the input sequence, to be tracked by the manager."""
 with self._Client(self._address, authkey=self._authkey) as conn:
 sl = shared_memory.ShareableList(sequence)
 try:
 dispatch(conn, None, 'track_segment', (sl.shm.name,))
 except BaseException as e:
 sl.shm.unlink()
 raise e
 return sl