#
# Module providing the `Process` class which emulates `threading.Thread`
#
# multiprocessing/process.py
#
# Copyright (c) 2006-2008, R Oudkerk
# Licensed to PSF under a Contributor Agreement.
#

__all__ = ['Process', 'current_process', 'active_children']

#
# Imports
#

import os
import sys
import signal
import itertools
from _weakrefset import WeakSet

#for brython
from _multiprocessing import Process
#
#
#

try:
    ORIGINAL_DIR = os.path.abspath(os.getcwd())
except OSError:
    ORIGINAL_DIR = None

#
# Public functions
#

def current_process():
    '''
    Return process object representing the current process
    '''
    return _current_process

def active_children():
    '''
    Return list of process objects corresponding to live child processes
    '''
    _cleanup()
    return list(_current_process._children)

#
#
#

def _cleanup():
    # check for processes which have finished
    for p in list(_current_process._children):
        if p._popen.poll() is not None:
            _current_process._children.discard(p)

#
# The `Process` class
#

# brython note: class Process is defined in /usr/libs/_multiprocessing.js


#
# We subclass bytes to avoid accidental transmission of auth keys over network
#

class AuthenticationString(bytes):
    def __reduce__(self):
        from .forking import Popen
        if not Popen.thread_is_spawning():
            raise TypeError(
                'Pickling an AuthenticationString object is '
                'disallowed for security reasons'
                )
        return AuthenticationString, (bytes(self),)

#
# Create object representing the main process
#

class _MainProcess(Process):

    def __init__(self):
        self._identity = ()
        self._daemonic = False
        self._name = 'MainProcess'
        self._parent_pid = None
        self._popen = None
        self._counter = itertools.count(1)
        self._children = set()
        self._authkey = AuthenticationString(os.urandom(32))
        self._tempdir = None

_current_process = _MainProcess()
del _MainProcess

#
# Give names to some return codes
#

_exitcode_to_name = {}

for name, signum in list(signal.__dict__.items()):
    if name[:3]=='SIG' and '_' not in name:
        _exitcode_to_name[-signum] = name

# For debug and leak testing
_dangling = WeakSet()