Initial commit

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/__init__.py

@@ -0,0 +1,16 @@
+import os
+import sys
+
+from .context import get_context
+
+if sys.version_info > (3, 4):
+
+    def _make_name():
+        name = '/loky-%i-%s' % (os.getpid(), next(synchronize.SemLock._rand))
+        return name
+
+    # monkey patch the name creation for multiprocessing
+    from multiprocessing import synchronize
+    synchronize.SemLock._make_name = staticmethod(_make_name)
+
+__all__ = ["get_context"]

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/_posix_reduction.py

@@ -0,0 +1,76 @@
+###############################################################################
+# Extra reducers for Unix based system and connections objects
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+# adapted from multiprocessing/reduction.py (17/02/2017)
+#  * Add adapted reduction for LokyProcesses and socket/Connection
+#
+import os
+import sys
+import socket
+import _socket
+
+from .reduction import register
+from .context import get_spawning_popen
+
+if sys.version_info >= (3, 3):
+    from multiprocessing.connection import Connection
+else:
+    from _multiprocessing import Connection
+
+
+HAVE_SEND_HANDLE = (hasattr(socket, 'CMSG_LEN') and
+                    hasattr(socket, 'SCM_RIGHTS') and
+                    hasattr(socket.socket, 'sendmsg'))
+
+
+def _mk_inheritable(fd):
+    if sys.version_info[:2] > (3, 3):
+        os.set_inheritable(fd, True)
+    return fd
+
+
+def DupFd(fd):
+    '''Return a wrapper for an fd.'''
+    popen_obj = get_spawning_popen()
+    if popen_obj is not None:
+        return popen_obj.DupFd(popen_obj.duplicate_for_child(fd))
+    elif HAVE_SEND_HANDLE and sys.version_info[:2] > (3, 3):
+        from multiprocessing import resource_sharer
+        return resource_sharer.DupFd(fd)
+    else:
+        raise TypeError(
+            'Cannot pickle connection object. This object can only be '
+            'passed when spawning a new process'
+        )
+
+
+if sys.version_info[:2] != (3, 3):
+    def _reduce_socket(s):
+        df = DupFd(s.fileno())
+        return _rebuild_socket, (df, s.family, s.type, s.proto)
+
+    def _rebuild_socket(df, family, type, proto):
+        fd = df.detach()
+        return socket.fromfd(fd, family, type, proto)
+else:
+    from multiprocessing.reduction import reduce_socket as _reduce_socket
+
+
+register(socket.socket, _reduce_socket)
+register(_socket.socket, _reduce_socket)
+
+
+if sys.version_info[:2] != (3, 3):
+    def reduce_connection(conn):
+        df = DupFd(conn.fileno())
+        return rebuild_connection, (df, conn.readable, conn.writable)
+
+    def rebuild_connection(df, readable, writable):
+        fd = df.detach()
+        return Connection(fd, readable, writable)
+else:
+    from multiprocessing.reduction import reduce_connection
+
+register(Connection, reduce_connection)

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/_posix_wait.py

@@ -0,0 +1,105 @@
+###############################################################################
+# Compat for wait function on UNIX based system
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+# adapted from multiprocessing/connection.py (17/02/2017)
+#  * Backport wait function to python2.7
+#
+
+import platform
+import select
+import socket
+import errno
+SYSTEM = platform.system()
+
+try:
+    import ctypes
+except ImportError:  # pragma: no cover
+    ctypes = None  # noqa
+
+if SYSTEM == 'Darwin' and ctypes is not None:
+    from ctypes.util import find_library
+    libSystem = ctypes.CDLL(find_library('libSystem.dylib'))
+    CoreServices = ctypes.CDLL(find_library('CoreServices'),
+                               use_errno=True)
+    mach_absolute_time = libSystem.mach_absolute_time
+    mach_absolute_time.restype = ctypes.c_uint64
+    absolute_to_nanoseconds = CoreServices.AbsoluteToNanoseconds
+    absolute_to_nanoseconds.restype = ctypes.c_uint64
+    absolute_to_nanoseconds.argtypes = [ctypes.c_uint64]
+
+    def monotonic():
+        return absolute_to_nanoseconds(mach_absolute_time()) * 1e-9
+
+elif SYSTEM == 'Linux' and ctypes is not None:
+    # from stackoverflow:
+    # questions/1205722/how-do-i-get-monotonic-time-durations-in-python
+    import ctypes
+    import os
+
+    CLOCK_MONOTONIC = 1  # see <linux/time.h>
+
+    class timespec(ctypes.Structure):
+        _fields_ = [
+            ('tv_sec', ctypes.c_long),
+            ('tv_nsec', ctypes.c_long),
+        ]
+
+    librt = ctypes.CDLL('librt.so.1', use_errno=True)
+    clock_gettime = librt.clock_gettime
+    clock_gettime.argtypes = [
+        ctypes.c_int, ctypes.POINTER(timespec),
+    ]
+
+    def monotonic():  # noqa
+        t = timespec()
+        if clock_gettime(CLOCK_MONOTONIC, ctypes.pointer(t)) != 0:
+            errno_ = ctypes.get_errno()
+            raise OSError(errno_, os.strerror(errno_))
+        return t.tv_sec + t.tv_nsec * 1e-9
+else:  # pragma: no cover
+    from time import time as monotonic
+
+
+if hasattr(select, 'poll'):
+    def _poll(fds, timeout):
+        if timeout is not None:
+            timeout = int(timeout * 1000)  # timeout is in milliseconds
+        fd_map = {}
+        pollster = select.poll()
+        for fd in fds:
+            pollster.register(fd, select.POLLIN)
+            if hasattr(fd, 'fileno'):
+                fd_map[fd.fileno()] = fd
+            else:
+                fd_map[fd] = fd
+        ls = []
+        for fd, event in pollster.poll(timeout):
+            if event & select.POLLNVAL:  # pragma: no cover
+                raise ValueError('invalid file descriptor %i' % fd)
+            ls.append(fd_map[fd])
+        return ls
+else:
+    def _poll(fds, timeout):
+        return select.select(fds, [], [], timeout)[0]
+
+
+def wait(object_list, timeout=None):
+    '''
+    Wait till an object in object_list is ready/readable.
+    Returns list of those objects which are ready/readable.
+    '''
+    if timeout is not None:
+        if timeout <= 0:
+            return _poll(object_list, 0)
+        else:
+            deadline = monotonic() + timeout
+    while True:
+        try:
+            return _poll(object_list, timeout)
+        except (OSError, IOError, socket.error) as e:  # pragma: no cover
+            if e.errno != errno.EINTR:
+                raise
+        if timeout is not None:
+            timeout = deadline - monotonic()

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/_win_reduction.py

@@ -0,0 +1,99 @@
+###############################################################################
+# Extra reducers for Windows system and connections objects
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+# adapted from multiprocessing/reduction.py (17/02/2017)
+#  * Add adapted reduction for LokyProcesses and socket/PipeConnection
+#
+import os
+import sys
+import socket
+from .reduction import register
+
+
+if sys.platform == 'win32':
+    if sys.version_info[:2] < (3, 3):
+        from _multiprocessing import PipeConnection
+    else:
+        import _winapi
+        from multiprocessing.connection import PipeConnection
+
+
+if sys.version_info[:2] >= (3, 4) and sys.platform == 'win32':
+    class DupHandle(object):
+        def __init__(self, handle, access, pid=None):
+            # duplicate handle for process with given pid
+            if pid is None:
+                pid = os.getpid()
+            proc = _winapi.OpenProcess(_winapi.PROCESS_DUP_HANDLE, False, pid)
+            try:
+                self._handle = _winapi.DuplicateHandle(
+                    _winapi.GetCurrentProcess(),
+                    handle, proc, access, False, 0)
+            finally:
+                _winapi.CloseHandle(proc)
+            self._access = access
+            self._pid = pid
+
+        def detach(self):
+            # retrieve handle from process which currently owns it
+            if self._pid == os.getpid():
+                return self._handle
+            proc = _winapi.OpenProcess(_winapi.PROCESS_DUP_HANDLE, False,
+                                       self._pid)
+            try:
+                return _winapi.DuplicateHandle(
+                    proc, self._handle, _winapi.GetCurrentProcess(),
+                    self._access, False, _winapi.DUPLICATE_CLOSE_SOURCE)
+            finally:
+                _winapi.CloseHandle(proc)
+
+    def reduce_pipe_connection(conn):
+        access = ((_winapi.FILE_GENERIC_READ if conn.readable else 0) |
+                  (_winapi.FILE_GENERIC_WRITE if conn.writable else 0))
+        dh = DupHandle(conn.fileno(), access)
+        return rebuild_pipe_connection, (dh, conn.readable, conn.writable)
+
+    def rebuild_pipe_connection(dh, readable, writable):
+        from multiprocessing.connection import PipeConnection
+        handle = dh.detach()
+        return PipeConnection(handle, readable, writable)
+    register(PipeConnection, reduce_pipe_connection)
+
+elif sys.platform == 'win32':
+    # Older Python versions
+    from multiprocessing.reduction import reduce_pipe_connection
+    register(PipeConnection, reduce_pipe_connection)
+
+
+if sys.version_info[:2] < (3, 3) and sys.platform == 'win32':
+    from _multiprocessing import win32
+    from multiprocessing.reduction import reduce_handle, rebuild_handle
+    close = win32.CloseHandle
+
+    def fromfd(handle, family, type_, proto=0):
+        s = socket.socket(family, type_, proto, fileno=handle)
+        if s.__class__ is not socket.socket:
+            s = socket.socket(_sock=s)
+        return s
+
+    def reduce_socket(s):
+        if not hasattr(socket, "fromfd"):
+            raise TypeError("sockets cannot be pickled on this system.")
+        reduced_handle = reduce_handle(s.fileno())
+        return _rebuild_socket, (reduced_handle, s.family, s.type, s.proto)
+
+    def _rebuild_socket(reduced_handle, family, type_, proto):
+        handle = rebuild_handle(reduced_handle)
+        s = fromfd(handle, family, type_, proto)
+        close(handle)
+        return s
+
+    register(socket.socket, reduce_socket)
+elif sys.version_info[:2] < (3, 4):
+    from multiprocessing.reduction import reduce_socket
+    register(socket.socket, reduce_socket)
+else:
+    from multiprocessing.reduction import _reduce_socket
+    register(socket.socket, _reduce_socket)

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/_win_wait.py

@@ -0,0 +1,58 @@
+###############################################################################
+# Compat for wait function on Windows system
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+# adapted from multiprocessing/connection.py (17/02/2017)
+#  * Backport wait function to python2.7
+#
+
+import ctypes
+import sys
+from time import sleep
+
+
+if sys.platform == 'win32' and sys.version_info[:2] < (3, 3):
+    from _subprocess import WaitForSingleObject, WAIT_OBJECT_0
+
+    try:
+        from time import monotonic
+    except ImportError:
+        # Backward old for crappy old Python that did not have cross-platform
+        # monotonic clock by default.
+
+        # TODO: do we want to add support for cygwin at some point? See:
+        # https://github.com/atdt/monotonic/blob/master/monotonic.py
+        GetTickCount64 = ctypes.windll.kernel32.GetTickCount64
+        GetTickCount64.restype = ctypes.c_ulonglong
+
+        def monotonic():
+            """Monotonic clock, cannot go backward."""
+            return GetTickCount64() / 1000.0
+
+    def wait(handles, timeout=None):
+        """Backward compat for python2.7
+
+        This function wait for either:
+        * one connection is ready for read,
+        * one process handle has exited or got killed,
+        * timeout is reached. Note that this function has a precision of 2
+          msec.
+        """
+        if timeout is not None:
+            deadline = monotonic() + timeout
+
+        while True:
+            # We cannot use select as in windows it only support sockets
+            ready = []
+            for h in handles:
+                if type(h) in [int, long]:
+                    if WaitForSingleObject(h, 0) == WAIT_OBJECT_0:
+                        ready += [h]
+                elif h.poll(0):
+                    ready.append(h)
+            if len(ready) > 0:
+                return ready
+            sleep(.001)
+            if timeout is not None and deadline - monotonic() <= 0:
+                return []

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/compat.py

@@ -0,0 +1,41 @@
+###############################################################################
+# Compat file to import the correct modules for each platform and python
+# version.
+#
+# author: Thomas Moreau and Olivier grisel
+#
+import sys
+
+PY3 = sys.version_info[:2] >= (3, 3)
+
+if PY3:
+    import queue
+else:
+    import Queue as queue
+
+if sys.version_info >= (3, 4):
+    from multiprocessing.process import BaseProcess
+else:
+    from multiprocessing.process import Process as BaseProcess
+
+# Platform specific compat
+if sys.platform == "win32":
+    from .compat_win32 import wait
+else:
+    from .compat_posix import wait
+
+
+def set_cause(exc, cause):
+    exc.__cause__ = cause
+
+    if not PY3:
+        # Preformat message here.
+        if exc.__cause__ is not None:
+            exc.args = ("{}\n\nThis was caused directly by {}".format(
+                exc.args if len(exc.args) != 1 else exc.args[0],
+                str(exc.__cause__)),)
+
+    return exc
+
+
+__all__ = ["queue", "BaseProcess", "set_cause", "wait"]

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/compat_posix.py

@@ -0,0 +1,13 @@
+# flake8: noqa
+###############################################################################
+# Compat file to load the correct wait function
+#
+# author: Thomas Moreau and Olivier grisel
+#
+import sys
+
+# Compat wait
+if sys.version_info < (3, 3):
+    from ._posix_wait import wait
+else:
+    from multiprocessing.connection import wait

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/compat_win32.py

@@ -0,0 +1,46 @@
+# flake8: noqa: F401
+import sys
+import numbers
+
+if sys.platform == "win32":
+    # Avoid import error by code introspection tools such as test runners
+    # trying to import this module while running on non-Windows systems.
+
+    # Compat Popen
+    if sys.version_info[:2] >= (3, 4):
+        from multiprocessing.popen_spawn_win32 import Popen
+    else:
+        from multiprocessing.forking import Popen
+
+    # wait compat
+    if sys.version_info[:2] < (3, 3):
+        from ._win_wait import wait
+    else:
+        from multiprocessing.connection import wait
+
+    # Compat _winapi
+    if sys.version_info[:2] >= (3, 4):
+        import _winapi
+    else:
+        import os
+        import msvcrt
+        if sys.version_info[:2] < (3, 3):
+            import _subprocess as win_api
+            from _multiprocessing import win32
+        else:
+            import _winapi as win_api
+
+        class _winapi:
+            CreateProcess = win_api.CreateProcess
+
+            @staticmethod
+            def CloseHandle(h):
+                if isinstance(h, numbers.Integral):
+                    # Cast long to int for 64-bit Python 2.7 under Windows
+                    h = int(h)
+                if sys.version_info[:2] < (3, 3):
+                    if not isinstance(h, int):
+                        h = h.Detach()
+                    win32.CloseHandle(h)
+                else:
+                    win_api.CloseHandle(h)

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/context.py

@@ -0,0 +1,265 @@
+###############################################################################
+# Basic context management with LokyContext and  provides
+# compat for UNIX 2.7 and 3.3
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+# adapted from multiprocessing/context.py
+#  * Create a context ensuring loky uses only objects that are compatible
+#  * Add LokyContext to the list of context of multiprocessing so loky can be
+#    used with multiprocessing.set_start_method
+#  * Add some compat function for python2.7 and 3.3.
+#
+from __future__ import division
+
+import os
+import sys
+import warnings
+import multiprocessing as mp
+
+
+from .process import LokyProcess, LokyInitMainProcess
+
+START_METHODS = ['loky', 'loky_init_main']
+_DEFAULT_START_METHOD = None
+
+if sys.version_info[:2] >= (3, 4):
+    from multiprocessing import get_context as mp_get_context
+    from multiprocessing.context import assert_spawning, set_spawning_popen
+    from multiprocessing.context import get_spawning_popen, BaseContext
+
+    START_METHODS += ['spawn']
+    if sys.platform != 'win32':
+        START_METHODS += ['fork', 'forkserver']
+
+    def get_context(method=None):
+        # Try to overload the default context
+        method = method or _DEFAULT_START_METHOD or "loky"
+        if method == "fork":
+            # If 'fork' is explicitly requested, warn user about potential
+            # issues.
+            warnings.warn("`fork` start method should not be used with "
+                          "`loky` as it does not respect POSIX. Try using "
+                          "`spawn` or `loky` instead.", UserWarning)
+        try:
+            context = mp_get_context(method)
+        except ValueError:
+            raise ValueError("Unknown context '{}'. Value should be in {}."
+                             .format(method, START_METHODS))
+
+        return context
+
+else:
+    if sys.platform != 'win32':
+        import threading
+        # Mechanism to check that the current thread is spawning a process
+        _tls = threading.local()
+        popen_attr = 'spawning_popen'
+    else:
+        from multiprocessing.forking import Popen
+        _tls = Popen._tls
+        popen_attr = 'process_handle'
+
+    BaseContext = object
+
+    def get_spawning_popen():
+        return getattr(_tls, popen_attr, None)
+
+    def set_spawning_popen(popen):
+        setattr(_tls, popen_attr, popen)
+
+    def assert_spawning(obj):
+        if get_spawning_popen() is None:
+            raise RuntimeError(
+                '%s objects should only be shared between processes'
+                ' through inheritance' % type(obj).__name__
+            )
+
+    def get_context(method=None):
+        method = method or _DEFAULT_START_METHOD or 'loky'
+        if method == "loky":
+            return LokyContext()
+        elif method == "loky_init_main":
+            return LokyInitMainContext()
+        else:
+            raise ValueError("Unknown context '{}'. Value should be in {}."
+                             .format(method, START_METHODS))
+
+
+def set_start_method(method, force=False):
+    global _DEFAULT_START_METHOD
+    if _DEFAULT_START_METHOD is not None and not force:
+        raise RuntimeError('context has already been set')
+    assert method is None or method in START_METHODS, (
+        "'{}' is not a valid start_method. It should be in {}"
+        .format(method, START_METHODS))
+
+    _DEFAULT_START_METHOD = method
+
+
+def get_start_method():
+    return _DEFAULT_START_METHOD
+
+
+def cpu_count():
+    """Return the number of CPUs the current process can use.
+
+    The returned number of CPUs accounts for:
+     * the number of CPUs in the system, as given by
+       ``multiprocessing.cpu_count``;
+     * the CPU affinity settings of the current process
+       (available with Python 3.4+ on some Unix systems);
+     * CFS scheduler CPU bandwidth limit (available on Linux only, typically
+       set by docker and similar container orchestration systems);
+     * the value of the LOKY_MAX_CPU_COUNT environment variable if defined.
+    and is given as the minimum of these constraints.
+    It is also always larger or equal to 1.
+    """
+    import math
+
+    try:
+        cpu_count_mp = mp.cpu_count()
+    except NotImplementedError:
+        cpu_count_mp = 1
+
+    # Number of available CPUs given affinity settings
+    cpu_count_affinity = cpu_count_mp
+    if hasattr(os, 'sched_getaffinity'):
+        try:
+            cpu_count_affinity = len(os.sched_getaffinity(0))
+        except NotImplementedError:
+            pass
+
+    # CFS scheduler CPU bandwidth limit
+    # available in Linux since 2.6 kernel
+    cpu_count_cfs = cpu_count_mp
+    cfs_quota_fname = "/sys/fs/cgroup/cpu/cpu.cfs_quota_us"
+    cfs_period_fname = "/sys/fs/cgroup/cpu/cpu.cfs_period_us"
+    if os.path.exists(cfs_quota_fname) and os.path.exists(cfs_period_fname):
+        with open(cfs_quota_fname, 'r') as fh:
+            cfs_quota_us = int(fh.read())
+        with open(cfs_period_fname, 'r') as fh:
+            cfs_period_us = int(fh.read())
+
+        if cfs_quota_us > 0 and cfs_period_us > 0:
+            # Make sure this quantity is an int as math.ceil returns a
+            # float in python2.7. (See issue #165)
+            cpu_count_cfs = int(math.ceil(cfs_quota_us / cfs_period_us))
+
+    # User defined soft-limit passed as an loky specific environment variable.
+    cpu_count_loky = int(os.environ.get('LOKY_MAX_CPU_COUNT', cpu_count_mp))
+    aggregate_cpu_count = min(cpu_count_mp, cpu_count_affinity, cpu_count_cfs,
+                              cpu_count_loky)
+    return max(aggregate_cpu_count, 1)
+
+
+class LokyContext(BaseContext):
+    """Context relying on the LokyProcess."""
+    _name = 'loky'
+    Process = LokyProcess
+    cpu_count = staticmethod(cpu_count)
+
+    def Queue(self, maxsize=0, reducers=None):
+        '''Returns a queue object'''
+        from .queues import Queue
+        return Queue(maxsize, reducers=reducers,
+                     ctx=self.get_context())
+
+    def SimpleQueue(self, reducers=None):
+        '''Returns a queue object'''
+        from .queues import SimpleQueue
+        return SimpleQueue(reducers=reducers, ctx=self.get_context())
+
+    if sys.version_info[:2] < (3, 4):
+        """Compat for python2.7/3.3 for necessary methods in Context"""
+        def get_context(self):
+            return self
+
+        def get_start_method(self):
+            return self._name
+
+        def Pipe(self, duplex=True):
+            '''Returns two connection object connected by a pipe'''
+            return mp.Pipe(duplex)
+
+        if sys.platform != "win32":
+            """Use the compat Manager for python2.7/3.3 on UNIX to avoid
+            relying on fork processes
+            """
+            def Manager(self):
+                """Returns a manager object"""
+                from .managers import LokyManager
+                m = LokyManager()
+                m.start()
+                return m
+        else:
+            """Compat for context on Windows and python2.7/3.3. Using regular
+            multiprocessing objects as it does not rely on fork.
+            """
+            from multiprocessing import synchronize
+            Semaphore = staticmethod(synchronize.Semaphore)
+            BoundedSemaphore = staticmethod(synchronize.BoundedSemaphore)
+            Lock = staticmethod(synchronize.Lock)
+            RLock = staticmethod(synchronize.RLock)
+            Condition = staticmethod(synchronize.Condition)
+            Event = staticmethod(synchronize.Event)
+            Manager = staticmethod(mp.Manager)
+
+    if sys.platform != "win32":
+        """For Unix platform, use our custom implementation of synchronize
+        relying on ctypes to interface with pthread semaphores.
+        """
+        def Semaphore(self, value=1):
+            """Returns a semaphore object"""
+            from .synchronize import Semaphore
+            return Semaphore(value=value)
+
+        def BoundedSemaphore(self, value):
+            """Returns a bounded semaphore object"""
+            from .synchronize import BoundedSemaphore
+            return BoundedSemaphore(value)
+
+        def Lock(self):
+            """Returns a lock object"""
+            from .synchronize import Lock
+            return Lock()
+
+        def RLock(self):
+            """Returns a recurrent lock object"""
+            from .synchronize import RLock
+            return RLock()
+
+        def Condition(self, lock=None):
+            """Returns a condition object"""
+            from .synchronize import Condition
+            return Condition(lock)
+
+        def Event(self):
+            """Returns an event object"""
+            from .synchronize import Event
+            return Event()
+
+
+class LokyInitMainContext(LokyContext):
+    """Extra context with LokyProcess, which does load the main module
+
+    This context is used for compatibility in the case ``cloudpickle`` is not
+    present on the running system. This permits to load functions defined in
+    the ``main`` module, using proper safeguards. The declaration of the
+    ``executor`` should be protected by ``if __name__ == "__main__":`` and the
+    functions and variable used from main should be out of this block.
+
+    This mimics the default behavior of multiprocessing under Windows and the
+    behavior of the ``spawn`` start method on a posix system for python3.4+.
+    For more details, see the end of the following section of python doc
+    https://docs.python.org/3/library/multiprocessing.html#multiprocessing-programming
+    """
+    _name = 'loky_init_main'
+    Process = LokyInitMainProcess
+
+
+if sys.version_info > (3, 4):
+    """Register loky context so it works with multiprocessing.get_context"""
+    ctx_loky = LokyContext()
+    mp.context._concrete_contexts['loky'] = ctx_loky
+    mp.context._concrete_contexts['loky_init_main'] = LokyInitMainContext()

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/fork_exec.py

@@ -0,0 +1,48 @@
+###############################################################################
+# Launch a subprocess using forkexec and make sure only the needed fd are
+# shared in the two process.
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+import os
+import sys
+
+if sys.platform == "darwin" and sys.version_info < (3, 3):
+    FileNotFoundError = OSError
+
+
+def close_fds(keep_fds):  # pragma: no cover
+    """Close all the file descriptors except those in keep_fds."""
+
+    # Make sure to keep stdout and stderr open for logging purpose
+    keep_fds = set(keep_fds).union([1, 2])
+
+    # We try to retrieve all the open fds
+    try:
+        open_fds = set(int(fd) for fd in os.listdir('/proc/self/fd'))
+    except FileNotFoundError:
+        import resource
+        max_nfds = resource.getrlimit(resource.RLIMIT_NOFILE)[0]
+        open_fds = set(fd for fd in range(3, max_nfds))
+        open_fds.add(0)
+
+    for i in open_fds - keep_fds:
+        try:
+            os.close(i)
+        except OSError:
+            pass
+
+
+def fork_exec(cmd, keep_fds, env=None):
+
+    # copy the environment variables to set in the child process
+    env = {} if env is None else env
+    child_env = os.environ.copy()
+    child_env.update(env)
+
+    pid = os.fork()
+    if pid == 0:  # pragma: no cover
+        close_fds(keep_fds)
+        os.execve(sys.executable, cmd, child_env)
+    else:
+        return pid

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/managers.py

@@ -0,0 +1,51 @@
+###############################################################################
+# compat for UNIX 2.7 and 3.3
+# Manager with LokyContext server.
+# This avoids having a Manager using fork and breaks the fd.
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+# based on multiprocessing/managers.py (17/02/2017)
+#  * Overload the start method to use LokyContext and launch a loky subprocess
+#
+
+import multiprocessing as mp
+from multiprocessing.managers import SyncManager, State
+from .process import LokyProcess as Process
+
+
+class LokyManager(SyncManager):
+    def start(self, initializer=None, initargs=()):
+        '''Spawn a server process for this manager object'''
+        assert self._state.value == State.INITIAL
+
+        if (initializer is not None
+                and not hasattr(initializer, '__call__')):
+            raise TypeError('initializer must be a callable')
+
+        # pipe over which we will retrieve address of server
+        reader, writer = mp.Pipe(duplex=False)
+
+        # spawn process which runs a server
+        self._process = Process(
+            target=type(self)._run_server,
+            args=(self._registry, self._address, bytes(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 = mp.util.Finalize(
+            self, type(self)._finalize_manager,
+            args=(self._process, self._address, self._authkey,
+                  self._state, self._Client),
+            exitpriority=0
+        )

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/popen_loky_posix.py

@@ -0,0 +1,211 @@
+###############################################################################
+# Popen for LokyProcess.
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+import os
+import sys
+import signal
+import pickle
+from io import BytesIO
+
+from . import reduction, spawn
+from .context import get_spawning_popen, set_spawning_popen
+from multiprocessing import util, process
+
+if sys.version_info[:2] < (3, 3):
+    ProcessLookupError = OSError
+
+if sys.platform != "win32":
+    from . import resource_tracker
+
+
+__all__ = []
+
+if sys.platform != "win32":
+    #
+    # Wrapper for an fd used while launching a process
+    #
+
+    class _DupFd(object):
+        def __init__(self, fd):
+            self.fd = reduction._mk_inheritable(fd)
+
+        def detach(self):
+            return self.fd
+
+    #
+    # Start child process using subprocess.Popen
+    #
+
+    __all__.append('Popen')
+
+    class Popen(object):
+        method = 'loky'
+        DupFd = _DupFd
+
+        def __init__(self, process_obj):
+            sys.stdout.flush()
+            sys.stderr.flush()
+            self.returncode = None
+            self._fds = []
+            self._launch(process_obj)
+
+        if sys.version_info < (3, 4):
+            @classmethod
+            def duplicate_for_child(cls, fd):
+                popen = get_spawning_popen()
+                popen._fds.append(fd)
+                return reduction._mk_inheritable(fd)
+
+        else:
+            def duplicate_for_child(self, fd):
+                self._fds.append(fd)
+                return reduction._mk_inheritable(fd)
+
+        def poll(self, flag=os.WNOHANG):
+            if self.returncode is None:
+                while True:
+                    try:
+                        pid, sts = os.waitpid(self.pid, flag)
+                    except OSError:
+                        # Child process not yet created. See #1731717
+                        # e.errno == errno.ECHILD == 10
+                        return None
+                    else:
+                        break
+                if pid == self.pid:
+                    if os.WIFSIGNALED(sts):
+                        self.returncode = -os.WTERMSIG(sts)
+                    else:
+                        assert os.WIFEXITED(sts)
+                        self.returncode = os.WEXITSTATUS(sts)
+            return self.returncode
+
+        def wait(self, timeout=None):
+            if sys.version_info < (3, 3):
+                import time
+                if timeout is None:
+                    return self.poll(0)
+                deadline = time.time() + timeout
+                delay = 0.0005
+                while 1:
+                    res = self.poll()
+                    if res is not None:
+                        break
+                    remaining = deadline - time.time()
+                    if remaining <= 0:
+                        break
+                    delay = min(delay * 2, remaining, 0.05)
+                    time.sleep(delay)
+                return res
+
+            if self.returncode is None:
+                if timeout is not None:
+                    from multiprocessing.connection import wait
+                    if not wait([self.sentinel], timeout):
+                        return None
+                # This shouldn't block if wait() returned successfully.
+                return self.poll(os.WNOHANG if timeout == 0.0 else 0)
+            return self.returncode
+
+        def terminate(self):
+            if self.returncode is None:
+                try:
+                    os.kill(self.pid, signal.SIGTERM)
+                except ProcessLookupError:
+                    pass
+                except OSError:
+                    if self.wait(timeout=0.1) is None:
+                        raise
+
+        def _launch(self, process_obj):
+
+            tracker_fd = resource_tracker._resource_tracker.getfd()
+
+            fp = BytesIO()
+            set_spawning_popen(self)
+            try:
+                prep_data = spawn.get_preparation_data(
+                    process_obj._name,
+                    getattr(process_obj, "init_main_module", True))
+                reduction.dump(prep_data, fp)
+                reduction.dump(process_obj, fp)
+
+            finally:
+                set_spawning_popen(None)
+
+            try:
+                parent_r, child_w = os.pipe()
+                child_r, parent_w = os.pipe()
+                # for fd in self._fds:
+                #     _mk_inheritable(fd)
+
+                cmd_python = [sys.executable]
+                cmd_python += ['-m', self.__module__]
+                cmd_python += ['--process-name', str(process_obj.name)]
+                cmd_python += ['--pipe',
+                               str(reduction._mk_inheritable(child_r))]
+                reduction._mk_inheritable(child_w)
+                reduction._mk_inheritable(tracker_fd)
+                self._fds.extend([child_r, child_w, tracker_fd])
+                from .fork_exec import fork_exec
+                pid = fork_exec(cmd_python, self._fds, env=process_obj.env)
+                util.debug("launched python with pid {} and cmd:\n{}"
+                           .format(pid, cmd_python))
+                self.sentinel = parent_r
+
+                method = 'getbuffer'
+                if not hasattr(fp, method):
+                    method = 'getvalue'
+                with os.fdopen(parent_w, 'wb') as f:
+                    f.write(getattr(fp, method)())
+                self.pid = pid
+            finally:
+                if parent_r is not None:
+                    util.Finalize(self, os.close, (parent_r,))
+                for fd in (child_r, child_w):
+                    if fd is not None:
+                        os.close(fd)
+
+        @staticmethod
+        def thread_is_spawning():
+            return True
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser('Command line parser')
+    parser.add_argument('--pipe', type=int, required=True,
+                        help='File handle for the pipe')
+    parser.add_argument('--process-name', type=str, default=None,
+                        help='Identifier for debugging purpose')
+
+    args = parser.parse_args()
+
+    info = dict()
+
+    exitcode = 1
+    try:
+        with os.fdopen(args.pipe, 'rb') as from_parent:
+            process.current_process()._inheriting = True
+            try:
+                prep_data = pickle.load(from_parent)
+                spawn.prepare(prep_data)
+                process_obj = pickle.load(from_parent)
+            finally:
+                del process.current_process()._inheriting
+
+        exitcode = process_obj._bootstrap()
+    except Exception:
+        print('\n\n' + '-' * 80)
+        print('{} failed with traceback: '.format(args.process_name))
+        print('-' * 80)
+        import traceback
+        print(traceback.format_exc())
+        print('\n' + '-' * 80)
+    finally:
+        if from_parent is not None:
+            from_parent.close()
+
+        sys.exit(exitcode)

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/popen_loky_win32.py

@@ -0,0 +1,173 @@
+import os
+import sys
+from pickle import load
+from multiprocessing import process, util
+
+from . import spawn
+from . import reduction
+from .context import get_spawning_popen, set_spawning_popen
+
+if sys.platform == "win32":
+    # Avoid import error by code introspection tools such as test runners
+    # trying to import this module while running on non-Windows systems.
+    import msvcrt
+    from .compat_win32 import _winapi
+    from .compat_win32 import Popen as _Popen
+    from .reduction import duplicate
+else:
+    _Popen = object
+
+if sys.version_info[:2] < (3, 3):
+    from os import fdopen as open
+
+__all__ = ['Popen']
+
+#
+#
+#
+
+TERMINATE = 0x10000
+WINEXE = (sys.platform == 'win32' and getattr(sys, 'frozen', False))
+WINSERVICE = sys.executable.lower().endswith("pythonservice.exe")
+
+
+def _path_eq(p1, p2):
+    return p1 == p2 or os.path.normcase(p1) == os.path.normcase(p2)
+
+
+WINENV = (hasattr(sys, "_base_executable")
+          and not _path_eq(sys.executable, sys._base_executable))
+
+#
+# We define a Popen class similar to the one from subprocess, but
+# whose constructor takes a process object as its argument.
+#
+
+
+class Popen(_Popen):
+    '''
+    Start a subprocess to run the code of a process object
+    '''
+    method = 'loky'
+
+    def __init__(self, process_obj):
+        prep_data = spawn.get_preparation_data(
+            process_obj._name, getattr(process_obj, "init_main_module", True))
+
+        # read end of pipe will be "stolen" by the child process
+        # -- see spawn_main() in spawn.py.
+        rfd, wfd = os.pipe()
+        rhandle = duplicate(msvcrt.get_osfhandle(rfd), inheritable=True)
+        os.close(rfd)
+
+        cmd = get_command_line(parent_pid=os.getpid(), pipe_handle=rhandle)
+        cmd = ' '.join('"%s"' % x for x in cmd)
+
+        python_exe = spawn.get_executable()
+
+        # copy the environment variables to set in the child process
+        child_env = os.environ.copy()
+        child_env.update(process_obj.env)
+
+        # bpo-35797: When running in a venv, we bypass the redirect
+        # executor and launch our base Python.
+        if WINENV and _path_eq(python_exe, sys.executable):
+            python_exe = sys._base_executable
+            child_env["__PYVENV_LAUNCHER__"] = sys.executable
+
+        try:
+            with open(wfd, 'wb') as to_child:
+                # start process
+                try:
+                    # This flag allows to pass inheritable handles from the
+                    # parent to the child process in a python2-3 compatible way
+                    # (see
+                    # https://github.com/tomMoral/loky/pull/204#discussion_r290719629
+                    # for more detail). When support for Python 2 is dropped,
+                    # the cleaner multiprocessing.reduction.steal_handle should
+                    # be used instead.
+                    inherit = True
+                    hp, ht, pid, tid = _winapi.CreateProcess(
+                        python_exe, cmd,
+                        None, None, inherit, 0,
+                        child_env, None, None)
+                    _winapi.CloseHandle(ht)
+                except BaseException:
+                    _winapi.CloseHandle(rhandle)
+                    raise
+
+                # set attributes of self
+                self.pid = pid
+                self.returncode = None
+                self._handle = hp
+                self.sentinel = int(hp)
+                util.Finalize(self, _winapi.CloseHandle, (self.sentinel,))
+
+                # send information to child
+                set_spawning_popen(self)
+                if sys.version_info[:2] < (3, 4):
+                    Popen._tls.process_handle = int(hp)
+                try:
+                    reduction.dump(prep_data, to_child)
+                    reduction.dump(process_obj, to_child)
+                finally:
+                    set_spawning_popen(None)
+                    if sys.version_info[:2] < (3, 4):
+                        del Popen._tls.process_handle
+        except IOError as exc:
+            # IOError 22 happens when the launched subprocess terminated before
+            # wfd.close is called. Thus we can safely ignore it.
+            if exc.errno != 22:
+                raise
+            util.debug("While starting {}, ignored a IOError 22"
+                       .format(process_obj._name))
+
+    def duplicate_for_child(self, handle):
+        assert self is get_spawning_popen()
+        return duplicate(handle, self.sentinel)
+
+
+def get_command_line(pipe_handle, **kwds):
+    '''
+    Returns prefix of command line used for spawning a child process
+    '''
+    if getattr(sys, 'frozen', False):
+        return ([sys.executable, '--multiprocessing-fork', pipe_handle])
+    else:
+        prog = 'from joblib.externals.loky.backend.popen_loky_win32 import main; main()'
+        opts = util._args_from_interpreter_flags()
+        return [spawn.get_executable()] + opts + [
+            '-c', prog, '--multiprocessing-fork', pipe_handle]
+
+
+def is_forking(argv):
+    '''
+    Return whether commandline indicates we are forking
+    '''
+    if len(argv) >= 2 and argv[1] == '--multiprocessing-fork':
+        assert len(argv) == 3
+        return True
+    else:
+        return False
+
+
+def main():
+    '''
+    Run code specified by data received over pipe
+    '''
+    assert is_forking(sys.argv)
+
+    handle = int(sys.argv[-1])
+    fd = msvcrt.open_osfhandle(handle, os.O_RDONLY)
+    from_parent = os.fdopen(fd, 'rb')
+
+    process.current_process()._inheriting = True
+    preparation_data = load(from_parent)
+    spawn.prepare(preparation_data)
+    self = load(from_parent)
+    process.current_process()._inheriting = False
+
+    from_parent.close()
+
+    exitcode = self._bootstrap()
+    exit(exitcode)

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/process.py

@@ -0,0 +1,108 @@
+###############################################################################
+# LokyProcess implementation
+#
+# authors: Thomas Moreau and Olivier Grisel
+#
+# based on multiprocessing/process.py  (17/02/2017)
+# * Add some compatibility function for python2.7 and 3.3
+#
+import os
+import sys
+from .compat import BaseProcess
+
+
+class LokyProcess(BaseProcess):
+    _start_method = 'loky'
+
+    def __init__(self, group=None, target=None, name=None, args=(),
+                 kwargs={}, daemon=None, init_main_module=False,
+                 env=None):
+        if sys.version_info < (3, 3):
+            super(LokyProcess, self).__init__(
+                group=group, target=target, name=name, args=args,
+                kwargs=kwargs)
+            self.daemon = daemon
+        else:
+            super(LokyProcess, self).__init__(
+                group=group, target=target, name=name, args=args,
+                kwargs=kwargs, daemon=daemon)
+        self.env = {} if env is None else env
+        self.authkey = self.authkey
+        self.init_main_module = init_main_module
+
+    @staticmethod
+    def _Popen(process_obj):
+        if sys.platform == "win32":
+            from .popen_loky_win32 import Popen
+        else:
+            from .popen_loky_posix import Popen
+        return Popen(process_obj)
+
+    if sys.version_info < (3, 3):
+        def start(self):
+            '''
+            Start child process
+            '''
+            from multiprocessing.process import _current_process, _cleanup
+            assert self._popen is None, 'cannot start a process twice'
+            assert self._parent_pid == os.getpid(), \
+                'can only start a process object created by current process'
+            _cleanup()
+            self._popen = self._Popen(self)
+            self._sentinel = self._popen.sentinel
+            _current_process._children.add(self)
+
+        @property
+        def sentinel(self):
+            '''
+            Return a file descriptor (Unix) or handle (Windows) suitable for
+            waiting for process termination.
+            '''
+            try:
+                return self._sentinel
+            except AttributeError:
+                raise ValueError("process not started")
+
+    if sys.version_info < (3, 4):
+        @property
+        def authkey(self):
+            return self._authkey
+
+        @authkey.setter
+        def authkey(self, authkey):
+            '''
+            Set authorization key of process
+            '''
+            self._authkey = AuthenticationKey(authkey)
+
+        def _bootstrap(self):
+            from .context import set_start_method
+            set_start_method(self._start_method)
+            super(LokyProcess, self)._bootstrap()
+
+
+class LokyInitMainProcess(LokyProcess):
+    _start_method = 'loky_init_main'
+
+    def __init__(self, group=None, target=None, name=None, args=(),
+                 kwargs={}, daemon=None):
+        super(LokyInitMainProcess, self).__init__(
+            group=group, target=target, name=name, args=args, kwargs=kwargs,
+            daemon=daemon, init_main_module=True)
+
+
+#
+# We subclass bytes to avoid accidental transmission of auth keys over network
+#
+
+class AuthenticationKey(bytes):
+    def __reduce__(self):
+        from .context import assert_spawning
+        try:
+            assert_spawning(self)
+        except RuntimeError:
+            raise TypeError(
+                'Pickling an AuthenticationKey object is '
+                'disallowed for security reasons'
+            )
+        return AuthenticationKey, (bytes(self),)

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/queues.py

@@ -0,0 +1,240 @@
+###############################################################################
+# Queue and SimpleQueue implementation for loky
+#
+# authors: Thomas Moreau, Olivier Grisel
+#
+# based on multiprocessing/queues.py (16/02/2017)
+# * Add some compatibility function for python2.7 and 3.3 and makes sure
+#   it uses the right synchronization primitive.
+# * Add some custom reducers for the Queues/SimpleQueue to tweak the
+#   pickling process. (overload Queue._feed/SimpleQueue.put)
+#
+import os
+import sys
+import errno
+import weakref
+import threading
+
+from multiprocessing import util
+from multiprocessing import connection
+from multiprocessing.synchronize import SEM_VALUE_MAX
+from multiprocessing.queues import Full
+from multiprocessing.queues import _sentinel, Queue as mp_Queue
+from multiprocessing.queues import SimpleQueue as mp_SimpleQueue
+
+from .reduction import loads, dumps
+from .context import assert_spawning, get_context
+
+
+__all__ = ['Queue', 'SimpleQueue', 'Full']
+
+
+class Queue(mp_Queue):
+
+    def __init__(self, maxsize=0, reducers=None, ctx=None):
+
+        if sys.version_info[:2] >= (3, 4):
+            super().__init__(maxsize=maxsize, ctx=ctx)
+        else:
+            if maxsize <= 0:
+                # Can raise ImportError (see issues #3770 and #23400)
+                maxsize = SEM_VALUE_MAX
+            if ctx is None:
+                ctx = get_context()
+            self._maxsize = maxsize
+            self._reader, self._writer = connection.Pipe(duplex=False)
+            self._rlock = ctx.Lock()
+            self._opid = os.getpid()
+            if sys.platform == 'win32':
+                self._wlock = None
+            else:
+                self._wlock = ctx.Lock()
+            self._sem = ctx.BoundedSemaphore(maxsize)
+
+            # For use by concurrent.futures
+            self._ignore_epipe = False
+
+            self._after_fork()
+
+            if sys.platform != 'win32':
+                util.register_after_fork(self, Queue._after_fork)
+
+        self._reducers = reducers
+
+    # Use custom queue set/get state to be able to reduce the custom reducers
+    def __getstate__(self):
+        assert_spawning(self)
+        return (self._ignore_epipe, self._maxsize, self._reader, self._writer,
+                self._reducers, self._rlock, self._wlock, self._sem,
+                self._opid)
+
+    def __setstate__(self, state):
+        (self._ignore_epipe, self._maxsize, self._reader, self._writer,
+         self._reducers, self._rlock, self._wlock, self._sem,
+         self._opid) = state
+        self._after_fork()
+
+    # Overload _start_thread to correctly call our custom _feed
+    def _start_thread(self):
+        util.debug('Queue._start_thread()')
+
+        # Start thread which transfers data from buffer to pipe
+        self._buffer.clear()
+        self._thread = threading.Thread(
+            target=Queue._feed,
+            args=(self._buffer, self._notempty, self._send_bytes,
+                  self._wlock, self._writer.close, self._reducers,
+                  self._ignore_epipe, self._on_queue_feeder_error, self._sem),
+            name='QueueFeederThread'
+        )
+        self._thread.daemon = True
+
+        util.debug('doing self._thread.start()')
+        self._thread.start()
+        util.debug('... done self._thread.start()')
+
+        # On process exit we will wait for data to be flushed to pipe.
+        #
+        # However, if this process created the queue then all
+        # processes which use the queue will be descendants of this
+        # process.  Therefore waiting for the queue to be flushed
+        # is pointless once all the child processes have been joined.
+        created_by_this_process = (self._opid == os.getpid())
+        if not self._joincancelled and not created_by_this_process:
+            self._jointhread = util.Finalize(
+                self._thread, Queue._finalize_join,
+                [weakref.ref(self._thread)],
+                exitpriority=-5
+            )
+
+        # Send sentinel to the thread queue object when garbage collected
+        self._close = util.Finalize(
+            self, Queue._finalize_close,
+            [self._buffer, self._notempty],
+            exitpriority=10
+        )
+
+    # Overload the _feed methods to use our custom pickling strategy.
+    @staticmethod
+    def _feed(buffer, notempty, send_bytes, writelock, close, reducers,
+              ignore_epipe, onerror, queue_sem):
+        util.debug('starting thread to feed data to pipe')
+        nacquire = notempty.acquire
+        nrelease = notempty.release
+        nwait = notempty.wait
+        bpopleft = buffer.popleft
+        sentinel = _sentinel
+        if sys.platform != 'win32':
+            wacquire = writelock.acquire
+            wrelease = writelock.release
+        else:
+            wacquire = None
+
+        while 1:
+            try:
+                nacquire()
+                try:
+                    if not buffer:
+                        nwait()
+                finally:
+                    nrelease()
+                try:
+                    while 1:
+                        obj = bpopleft()
+                        if obj is sentinel:
+                            util.debug('feeder thread got sentinel -- exiting')
+                            close()
+                            return
+
+                        # serialize the data before acquiring the lock
+                        obj_ = dumps(obj, reducers=reducers)
+                        if wacquire is None:
+                            send_bytes(obj_)
+                        else:
+                            wacquire()
+                            try:
+                                send_bytes(obj_)
+                            finally:
+                                wrelease()
+                        # Remove references early to avoid leaking memory
+                        del obj, obj_
+                except IndexError:
+                    pass
+            except BaseException as e:
+                if ignore_epipe and getattr(e, 'errno', 0) == errno.EPIPE:
+                    return
+                # Since this runs in a daemon thread the resources it uses
+                # may be become unusable while the process is cleaning up.
+                # We ignore errors which happen after the process has
+                # started to cleanup.
+                if util.is_exiting():
+                    util.info('error in queue thread: %s', e)
+                    return
+                else:
+                    queue_sem.release()
+                    onerror(e, obj)
+
+    def _on_queue_feeder_error(self, e, obj):
+        """
+        Private API hook called when feeding data in the background thread
+        raises an exception.  For overriding by concurrent.futures.
+        """
+        import traceback
+        traceback.print_exc()
+
+    if sys.version_info[:2] < (3, 4):
+        # Compat for python2.7/3.3 that use _send instead of _send_bytes
+        def _after_fork(self):
+            super(Queue, self)._after_fork()
+            self._send_bytes = self._writer.send_bytes
+
+
+class SimpleQueue(mp_SimpleQueue):
+
+    def __init__(self, reducers=None, ctx=None):
+        if sys.version_info[:2] >= (3, 4):
+            super().__init__(ctx=ctx)
+        else:
+            # Use the context to create the sync objects for python2.7/3.3
+            if ctx is None:
+                ctx = get_context()
+            self._reader, self._writer = connection.Pipe(duplex=False)
+            self._rlock = ctx.Lock()
+            self._poll = self._reader.poll
+            if sys.platform == 'win32':
+                self._wlock = None
+            else:
+                self._wlock = ctx.Lock()
+
+        # Add possiblity to use custom reducers
+        self._reducers = reducers
+
+    # Use custom queue set/get state to be able to reduce the custom reducers
+    def __getstate__(self):
+        assert_spawning(self)
+        return (self._reader, self._writer, self._reducers, self._rlock,
+                self._wlock)
+
+    def __setstate__(self, state):
+        (self._reader, self._writer, self._reducers, self._rlock,
+         self._wlock) = state
+
+    if sys.version_info[:2] < (3, 4):
+        # For python2.7/3.3, overload get to avoid creating deadlocks with
+        # unpickling errors.
+        def get(self):
+            with self._rlock:
+                res = self._reader.recv_bytes()
+            # unserialize the data after having released the lock
+            return loads(res)
+
+    # Overload put to use our customizable reducer
+    def put(self, obj):
+        # serialize the data before acquiring the lock
+        obj = dumps(obj, reducers=self._reducers)
+        if self._wlock is None:
+            # writes to a message oriented win32 pipe are atomic
+            self._writer.send_bytes(obj)
+        else:
+            with self._wlock:
+                self._writer.send_bytes(obj)

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/reduction.py

@@ -0,0 +1,256 @@
+###############################################################################
+# Customizable Pickler with some basic reducers
+#
+# author: Thomas Moreau
+#
+# adapted from multiprocessing/reduction.py (17/02/2017)
+#  * Replace the ForkingPickler with a similar _LokyPickler,
+#  * Add CustomizableLokyPickler to allow customizing pickling process
+#    on the fly.
+#
+import io
+import os
+import sys
+import functools
+from multiprocessing import util
+try:
+    # Python 2 compat
+    from cPickle import loads as pickle_loads
+except ImportError:
+    from pickle import loads as pickle_loads
+    import copyreg
+
+from pickle import HIGHEST_PROTOCOL
+
+
+if sys.platform == "win32":
+    if sys.version_info[:2] > (3, 3):
+        from multiprocessing.reduction import duplicate
+    else:
+        from multiprocessing.forking import duplicate
+
+
+###############################################################################
+# Enable custom pickling in Loky.
+# To allow instance customization of the pickling process, we use 2 classes.
+# _ReducerRegistry gives module level customization and CustomizablePickler
+# permits to use instance base custom reducers. Only CustomizablePickler
+# should be used.
+
+class _ReducerRegistry(object):
+    """Registry for custom reducers.
+
+    HIGHEST_PROTOCOL is selected by default as this pickler is used
+    to pickle ephemeral datastructures for interprocess communication
+    hence no backward compatibility is required.
+
+    """
+
+    # We override the pure Python pickler as its the only way to be able to
+    # customize the dispatch table without side effects in Python 2.6
+    # to 3.2. For Python 3.3+ leverage the new dispatch_table
+    # feature from http://bugs.python.org/issue14166 that makes it possible
+    # to use the C implementation of the Pickler which is faster.
+
+    dispatch_table = {}
+
+    @classmethod
+    def register(cls, type, reduce_func):
+        """Attach a reducer function to a given type in the dispatch table."""
+        if sys.version_info < (3,):
+            # Python 2 pickler dispatching is not explicitly customizable.
+            # Let us use a closure to workaround this limitation.
+            def dispatcher(cls, obj):
+                reduced = reduce_func(obj)
+                cls.save_reduce(obj=obj, *reduced)
+            cls.dispatch_table[type] = dispatcher
+        else:
+            cls.dispatch_table[type] = reduce_func
+
+
+###############################################################################
+# Registers extra pickling routines to improve picklization  for loky
+
+register = _ReducerRegistry.register
+
+
+# make methods picklable
+def _reduce_method(m):
+    if m.__self__ is None:
+        return getattr, (m.__class__, m.__func__.__name__)
+    else:
+        return getattr, (m.__self__, m.__func__.__name__)
+
+
+class _C:
+    def f(self):
+        pass
+
+    @classmethod
+    def h(cls):
+        pass
+
+
+register(type(_C().f), _reduce_method)
+register(type(_C.h), _reduce_method)
+
+
+if not hasattr(sys, "pypy_version_info"):
+    # PyPy uses functions instead of method_descriptors and wrapper_descriptors
+    def _reduce_method_descriptor(m):
+        return getattr, (m.__objclass__, m.__name__)
+
+    register(type(list.append), _reduce_method_descriptor)
+    register(type(int.__add__), _reduce_method_descriptor)
+
+
+# Make partial func pickable
+def _reduce_partial(p):
+    return _rebuild_partial, (p.func, p.args, p.keywords or {})
+
+
+def _rebuild_partial(func, args, keywords):
+    return functools.partial(func, *args, **keywords)
+
+
+register(functools.partial, _reduce_partial)
+
+if sys.platform != "win32":
+    from ._posix_reduction import _mk_inheritable  # noqa: F401
+else:
+    from . import _win_reduction  # noqa: F401
+
+# global variable to change the pickler behavior
+try:
+    from joblib.externals import cloudpickle  # noqa: F401
+    DEFAULT_ENV = "cloudpickle"
+except ImportError:
+    # If cloudpickle is not present, fallback to pickle
+    DEFAULT_ENV = "pickle"
+
+ENV_LOKY_PICKLER = os.environ.get("LOKY_PICKLER", DEFAULT_ENV)
+_LokyPickler = None
+_loky_pickler_name = None
+
+
+def set_loky_pickler(loky_pickler=None):
+    global _LokyPickler, _loky_pickler_name
+
+    if loky_pickler is None:
+        loky_pickler = ENV_LOKY_PICKLER
+
+    loky_pickler_cls = None
+
+    # The default loky_pickler is cloudpickle
+    if loky_pickler in ["", None]:
+        loky_pickler = "cloudpickle"
+
+    if loky_pickler == _loky_pickler_name:
+        return
+
+    if loky_pickler == "cloudpickle":
+        from joblib.externals.cloudpickle import CloudPickler as loky_pickler_cls
+    else:
+        try:
+            from importlib import import_module
+            module_pickle = import_module(loky_pickler)
+            loky_pickler_cls = module_pickle.Pickler
+        except (ImportError, AttributeError) as e:
+            extra_info = ("\nThis error occurred while setting loky_pickler to"
+                          " '{}', as required by the env variable LOKY_PICKLER"
+                          " or the function set_loky_pickler."
+                          .format(loky_pickler))
+            e.args = (e.args[0] + extra_info,) + e.args[1:]
+            e.msg = e.args[0]
+            raise e
+
+    util.debug("Using '{}' for serialization."
+               .format(loky_pickler if loky_pickler else "cloudpickle"))
+
+    class CustomizablePickler(loky_pickler_cls):
+        _loky_pickler_cls = loky_pickler_cls
+
+        if sys.version_info < (3,):
+            # Make the dispatch registry an instance level attribute instead of
+            # a reference to the class dictionary under Python 2
+            _dispatch = loky_pickler_cls.dispatch.copy()
+            _dispatch.update(_ReducerRegistry.dispatch_table)
+        else:
+            # Under Python 3 initialize the dispatch table with a copy of the
+            # default registry
+            _dispatch_table = copyreg.dispatch_table.copy()
+            _dispatch_table.update(_ReducerRegistry.dispatch_table)
+
+        def __init__(self, writer, reducers=None, protocol=HIGHEST_PROTOCOL):
+            loky_pickler_cls.__init__(self, writer, protocol=protocol)
+            if reducers is None:
+                reducers = {}
+            if sys.version_info < (3,):
+                self.dispatch = self._dispatch.copy()
+            else:
+                if getattr(self, "dispatch_table", None) is not None:
+                    self.dispatch_table.update(self._dispatch_table.copy())
+                else:
+                    self.dispatch_table = self._dispatch_table.copy()
+
+            for type, reduce_func in reducers.items():
+                self.register(type, reduce_func)
+
+        def register(self, type, reduce_func):
+            """Attach a reducer function to a given type in the dispatch table.
+            """
+            if sys.version_info < (3,):
+                # Python 2 pickler dispatching is not explicitly customizable.
+                # Let us use a closure to workaround this limitation.
+                    def dispatcher(self, obj):
+                        reduced = reduce_func(obj)
+                        self.save_reduce(obj=obj, *reduced)
+                    self.dispatch[type] = dispatcher
+            else:
+                self.dispatch_table[type] = reduce_func
+
+    _LokyPickler = CustomizablePickler
+    _loky_pickler_name = loky_pickler
+
+
+def get_loky_pickler_name():
+    global _loky_pickler_name
+    return _loky_pickler_name
+
+
+def get_loky_pickler():
+    global _LokyPickler
+    return _LokyPickler
+
+
+# Set it to its default value
+set_loky_pickler()
+
+
+def loads(buf):
+    # Compat for python2.7 version
+    if sys.version_info < (3, 3) and isinstance(buf, io.BytesIO):
+        buf = buf.getvalue()
+    return pickle_loads(buf)
+
+
+def dump(obj, file, reducers=None, protocol=None):
+    '''Replacement for pickle.dump() using _LokyPickler.'''
+    global _LokyPickler
+    _LokyPickler(file, reducers=reducers, protocol=protocol).dump(obj)
+
+
+def dumps(obj, reducers=None, protocol=None):
+    global _LokyPickler
+
+    buf = io.BytesIO()
+    dump(obj, buf, reducers=reducers, protocol=protocol)
+    if sys.version_info < (3, 3):
+        return buf.getvalue()
+    return buf.getbuffer()
+
+
+__all__ = ["dump", "dumps", "loads", "register", "set_loky_pickler"]
+
+if sys.platform == "win32":
+    __all__ += ["duplicate"]

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/resource_tracker.py

@@ -0,0 +1,313 @@
+###############################################################################
+# Server process to keep track of unlinked resources, like folders and
+# semaphores and clean them.
+#
+# author: Thomas Moreau
+#
+# adapted from multiprocessing/semaphore_tracker.py  (17/02/2017)
+#  * include custom spawnv_passfds to start the process
+#  * use custom unlink from our own SemLock implementation
+#  * add some VERBOSE logging
+#
+
+#
+# On Unix we run a server process which keeps track of unlinked
+# resources. The server ignores SIGINT and SIGTERM and reads from a
+# pipe.  Every other process of the program has a copy of the writable
+# end of the pipe, so we get EOF when all other processes have exited.
+# Then the server process unlinks any remaining resources.
+#
+# For semaphores, this is important because the system only supports a limited
+# number of named semaphores, and they will not be automatically removed till
+# the next reboot.  Without this resource tracker process, "killall python"
+# would probably leave unlinked semaphores.
+
+import os
+import shutil
+import sys
+import signal
+import warnings
+import threading
+
+from . import spawn
+from multiprocessing import util
+
+if sys.platform == "win32":
+    from .compat_win32 import _winapi
+    from .reduction import duplicate
+    import msvcrt
+
+try:
+    from _multiprocessing import sem_unlink
+except ImportError:
+    from .semlock import sem_unlink
+
+if sys.version_info < (3,):
+    BrokenPipeError = OSError
+    from os import fdopen as open
+
+__all__ = ['ensure_running', 'register', 'unregister']
+
+_HAVE_SIGMASK = hasattr(signal, 'pthread_sigmask')
+_IGNORED_SIGNALS = (signal.SIGINT, signal.SIGTERM)
+
+_CLEANUP_FUNCS = {
+    'folder': shutil.rmtree
+}
+
+if os.name == "posix":
+    _CLEANUP_FUNCS['semlock'] = sem_unlink
+
+VERBOSE = False
+
+
+class ResourceTracker(object):
+
+    def __init__(self):
+        self._lock = threading.Lock()
+        self._fd = None
+        self._pid = None
+
+    def getfd(self):
+        self.ensure_running()
+        return self._fd
+
+    def ensure_running(self):
+        '''Make sure that resource tracker process is running.
+
+        This can be run from any process.  Usually a child process will use
+        the resource created by its parent.'''
+        with self._lock:
+            if self._fd is not None:
+                # resource tracker was launched before, is it still running?
+                if self._check_alive():
+                    # => still alive
+                    return
+                # => dead, launch it again
+                os.close(self._fd)
+                if os.name == "posix":
+                    try:
+                        # At this point, the resource_tracker process has been
+                        # killed or crashed. Let's remove the process entry
+                        # from the process table to avoid zombie processes.
+                        os.waitpid(self._pid, 0)
+                    except OSError:
+                        # The process was terminated or is a child from an
+                        # ancestor of the current process.
+                        pass
+                self._fd = None
+                self._pid = None
+
+                warnings.warn('resource_tracker: process died unexpectedly, '
+                              'relaunching.  Some folders/sempahores might '
+                              'leak.')
+
+            fds_to_pass = []
+            try:
+                fds_to_pass.append(sys.stderr.fileno())
+            except Exception:
+                pass
+
+            r, w = os.pipe()
+            if sys.platform == "win32":
+                _r = duplicate(msvcrt.get_osfhandle(r), inheritable=True)
+                os.close(r)
+                r = _r
+
+            cmd = 'from {} import main; main({}, {})'.format(
+                main.__module__, r, VERBOSE)
+            try:
+                fds_to_pass.append(r)
+                # process will out live us, so no need to wait on pid
+                exe = spawn.get_executable()
+                args = [exe] + util._args_from_interpreter_flags()
+                # In python 3.3, there is a bug which put `-RRRRR..` instead of
+                # `-R` in args. Replace it to get the correct flags.
+                # See https://github.com/python/cpython/blob/3.3/Lib/subprocess.py#L488
+                if sys.version_info[:2] <= (3, 3):
+                    import re
+                    for i in range(1, len(args)):
+                        args[i] = re.sub("-R+", "-R", args[i])
+                args += ['-c', cmd]
+                util.debug("launching resource tracker: {}".format(args))
+                # bpo-33613: Register a signal mask that will block the
+                # signals.  This signal mask will be inherited by the child
+                # that is going to be spawned and will protect the child from a
+                # race condition that can make the child die before it
+                # registers signal handlers for SIGINT and SIGTERM. The mask is
+                # unregistered after spawning the child.
+                try:
+                    if _HAVE_SIGMASK:
+                        signal.pthread_sigmask(signal.SIG_BLOCK,
+                                               _IGNORED_SIGNALS)
+                    pid = spawnv_passfds(exe, args, fds_to_pass)
+                finally:
+                    if _HAVE_SIGMASK:
+                        signal.pthread_sigmask(signal.SIG_UNBLOCK,
+                                               _IGNORED_SIGNALS)
+            except BaseException:
+                os.close(w)
+                raise
+            else:
+                self._fd = w
+                self._pid = pid
+            finally:
+                if sys.platform == "win32":
+                    _winapi.CloseHandle(r)
+                else:
+                    os.close(r)
+
+    def _check_alive(self):
+        '''Check for the existence of the resource tracker process.'''
+        try:
+            self._send('PROBE', '', '')
+        except BrokenPipeError:
+            return False
+        else:
+            return True
+
+    def register(self, name, rtype):
+        '''Register a named resource with resource tracker.'''
+        self.ensure_running()
+        self._send('REGISTER', name, rtype)
+
+    def unregister(self, name, rtype):
+        '''Unregister a named resource with resource tracker.'''
+        self.ensure_running()
+        self._send('UNREGISTER', name, rtype)
+
+    def _send(self, cmd, name, rtype):
+        msg = '{0}:{1}:{2}\n'.format(cmd, name, rtype).encode('ascii')
+        if len(name) > 512:
+            # posix guarantees that writes to a pipe of less than PIPE_BUF
+            # bytes are atomic, and that PIPE_BUF >= 512
+            raise ValueError('name too long')
+        nbytes = os.write(self._fd, msg)
+        assert nbytes == len(msg)
+
+
+_resource_tracker = ResourceTracker()
+ensure_running = _resource_tracker.ensure_running
+register = _resource_tracker.register
+unregister = _resource_tracker.unregister
+getfd = _resource_tracker.getfd
+
+
+def main(fd, verbose=0):
+    '''Run resource tracker.'''
+    # protect the process from ^C and "killall python" etc
+    signal.signal(signal.SIGINT, signal.SIG_IGN)
+    signal.signal(signal.SIGTERM, signal.SIG_IGN)
+
+    if _HAVE_SIGMASK:
+        signal.pthread_sigmask(signal.SIG_UNBLOCK, _IGNORED_SIGNALS)
+
+    for f in (sys.stdin, sys.stdout):
+        try:
+            f.close()
+        except Exception:
+            pass
+
+    if verbose:  # pragma: no cover
+        sys.stderr.write("Main resource tracker is running\n")
+        sys.stderr.flush()
+
+    cache = {rtype: set() for rtype in _CLEANUP_FUNCS.keys()}
+    try:
+        # keep track of registered/unregistered resources
+        if sys.platform == "win32":
+            fd = msvcrt.open_osfhandle(fd, os.O_RDONLY)
+        with open(fd, 'rb') as f:
+            for line in f:
+                try:
+                    splitted = line.strip().decode('ascii').split(':')
+                    # name can potentially contain separator symbols (for
+                    # instance folders on Windows)
+                    cmd, name, rtype = (
+                        splitted[0], ':'.join(splitted[1:-1]), splitted[-1])
+
+                    if cmd == 'PROBE':
+                        continue
+
+                    if rtype not in _CLEANUP_FUNCS:
+                        raise ValueError(
+                            'Cannot register {} for automatic cleanup: '
+                            'unknown resource type ({}). Resource type should '
+                            'be one of the following: {}'.format(
+                                name, rtype, list(_CLEANUP_FUNCS.keys())))
+
+                    if cmd == 'REGISTER':
+                        cache[rtype].add(name)
+                        if verbose:  # pragma: no cover
+                            sys.stderr.write("[ResourceTracker] register {}"
+                                             " {}\n" .format(rtype, name))
+                            sys.stderr.flush()
+                    elif cmd == 'UNREGISTER':
+                        cache[rtype].remove(name)
+                        if verbose:  # pragma: no cover
+                            sys.stderr.write("[ResourceTracker] unregister {}"
+                                             " {}: cache({})\n"
+                                             .format(name, rtype, len(cache)))
+                            sys.stderr.flush()
+                    else:
+                        raise RuntimeError('unrecognized command %r' % cmd)
+                except BaseException:
+                    try:
+                        sys.excepthook(*sys.exc_info())
+                    except BaseException:
+                        pass
+    finally:
+        # all processes have terminated; cleanup any remaining resources
+        for rtype, rtype_cache in cache.items():
+            if rtype_cache:
+                try:
+                    warnings.warn('resource_tracker: There appear to be %d '
+                                  'leaked %s objects to clean up at shutdown' %
+                                  (len(rtype_cache), rtype))
+                except Exception:
+                    pass
+            for name in rtype_cache:
+                # For some reason the process which created and registered this
+                # resource has failed to unregister it. Presumably it has
+                # died.  We therefore clean it up.
+                try:
+                    _CLEANUP_FUNCS[rtype](name)
+                    if verbose:  # pragma: no cover
+                        sys.stderr.write("[ResourceTracker] unlink {}\n"
+                                         .format(name))
+                        sys.stderr.flush()
+                except Exception as e:
+                    warnings.warn('resource_tracker: %s: %r' % (name, e))
+
+    if verbose:  # pragma: no cover
+        sys.stderr.write("resource tracker shut down\n")
+        sys.stderr.flush()
+
+
+#
+# Start a program with only specified fds kept open
+#
+
+def spawnv_passfds(path, args, passfds):
+    passfds = sorted(passfds)
+    if sys.platform != "win32":
+        errpipe_read, errpipe_write = os.pipe()
+        try:
+            from .reduction import _mk_inheritable
+            _pass = []
+            for fd in passfds:
+                _pass += [_mk_inheritable(fd)]
+            from .fork_exec import fork_exec
+            return fork_exec(args, _pass)
+        finally:
+            os.close(errpipe_read)
+            os.close(errpipe_write)
+    else:
+        cmd = ' '.join('"%s"' % x for x in args)
+        try:
+            hp, ht, pid, tid = _winapi.CreateProcess(
+                path, cmd, None, None, True, 0, None, None, None)
+            _winapi.CloseHandle(ht)
+        except BaseException:
+            pass
+        return pid

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/semlock.py

@@ -0,0 +1,274 @@
+###############################################################################
+# Ctypes implementation for posix semaphore.
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+# adapted from cpython/Modules/_multiprocessing/semaphore.c (17/02/2017)
+#  * use ctypes to access pthread semaphores and provide a full python
+#    semaphore management.
+#  * For OSX, as no sem_getvalue is not implemented, Semaphore with value > 1
+#    are not guaranteed to work.
+#  * Only work with LokyProcess on posix
+#
+import os
+import sys
+import time
+import errno
+import ctypes
+import tempfile
+import threading
+from ctypes.util import find_library
+
+# As we need to use ctypes return types for semlock object, failure value
+# needs to be cast to proper python value. Unix failure convention is to
+# return 0, whereas OSX returns -1
+SEM_FAILURE = ctypes.c_void_p(0).value
+if sys.platform == 'darwin':
+    SEM_FAILURE = ctypes.c_void_p(-1).value
+
+# Semaphore types
+RECURSIVE_MUTEX = 0
+SEMAPHORE = 1
+
+# Semaphore constants
+SEM_OFLAG = ctypes.c_int(os.O_CREAT | os.O_EXCL)
+SEM_PERM = ctypes.c_int(384)
+
+
+class timespec(ctypes.Structure):
+    _fields_ = [("tv_sec", ctypes.c_long), ("tv_nsec", ctypes.c_long)]
+
+
+if sys.platform != 'win32':
+    pthread = ctypes.CDLL(find_library('pthread'), use_errno=True)
+    pthread.sem_open.restype = ctypes.c_void_p
+    pthread.sem_close.argtypes = [ctypes.c_void_p]
+    pthread.sem_wait.argtypes = [ctypes.c_void_p]
+    pthread.sem_trywait.argtypes = [ctypes.c_void_p]
+    pthread.sem_post.argtypes = [ctypes.c_void_p]
+    pthread.sem_getvalue.argtypes = [ctypes.c_void_p, ctypes.c_void_p]
+    pthread.sem_unlink.argtypes = [ctypes.c_char_p]
+    if sys.platform != "darwin":
+        pthread.sem_timedwait.argtypes = [ctypes.c_void_p,
+                                          ctypes.POINTER(timespec)]
+
+try:
+    from threading import get_ident
+except ImportError:
+    def get_ident():
+        return threading.current_thread().ident
+
+
+if sys.version_info[:2] < (3, 3):
+    class FileExistsError(OSError):
+        pass
+
+    class FileNotFoundError(OSError):
+        pass
+
+
+def sem_unlink(name):
+    if pthread.sem_unlink(name.encode('ascii')) < 0:
+        raiseFromErrno()
+
+
+def _sem_open(name, value=None):
+    """ Construct or retrieve a semaphore with the given name
+
+    If value is None, try to retrieve an existing named semaphore.
+    Else create a new semaphore with the given value
+    """
+    if value is None:
+        handle = pthread.sem_open(ctypes.c_char_p(name), 0)
+    else:
+        handle = pthread.sem_open(ctypes.c_char_p(name), SEM_OFLAG, SEM_PERM,
+                                  ctypes.c_int(value))
+
+    if handle == SEM_FAILURE:
+        e = ctypes.get_errno()
+        if e == errno.EEXIST:
+            raise FileExistsError("a semaphore named %s already exists" % name)
+        elif e == errno.ENOENT:
+            raise FileNotFoundError('cannot find semaphore named %s' % name)
+        elif e == errno.ENOSYS:
+            raise NotImplementedError('No semaphore implementation on this '
+                                      'system')
+        else:
+            raiseFromErrno()
+
+    return handle
+
+
+def _sem_timedwait(handle, timeout):
+    t_start = time.time()
+    if sys.platform != "darwin":
+        sec = int(timeout)
+        tv_sec = int(t_start)
+        nsec = int(1e9 * (timeout - sec) + .5)
+        tv_nsec = int(1e9 * (t_start - tv_sec) + .5)
+        deadline = timespec(sec+tv_sec, nsec+tv_nsec)
+        deadline.tv_sec += int(deadline.tv_nsec / 1000000000)
+        deadline.tv_nsec %= 1000000000
+        return pthread.sem_timedwait(handle, ctypes.pointer(deadline))
+
+    # PERFORMANCE WARNING
+    # No sem_timedwait on OSX so we implement our own method. This method can
+    # degrade performances has the wait can have a latency up to 20 msecs
+    deadline = t_start + timeout
+    delay = 0
+    now = time.time()
+    while True:
+        # Poll the sem file
+        res = pthread.sem_trywait(handle)
+        if res == 0:
+            return 0
+        else:
+            e = ctypes.get_errno()
+            if e != errno.EAGAIN:
+                raiseFromErrno()
+
+        # check for timeout
+        now = time.time()
+        if now > deadline:
+            ctypes.set_errno(errno.ETIMEDOUT)
+            return -1
+
+        # calculate how much time left and check the delay is not too long
+        # -- maximum is 20 msecs
+        difference = (deadline - now)
+        delay = min(delay, 20e-3, difference)
+
+        # Sleep and increase delay
+        time.sleep(delay)
+        delay += 1e-3
+
+
+class SemLock(object):
+    """ctypes wrapper to the unix semaphore"""
+
+    _rand = tempfile._RandomNameSequence()
+
+    def __init__(self, kind, value, maxvalue, name=None, unlink_now=False):
+        self.count = 0
+        self.ident = 0
+        self.kind = kind
+        self.maxvalue = maxvalue
+        self.name = name
+        self.handle = _sem_open(self.name.encode('ascii'), value)
+
+    def __del__(self):
+        try:
+            res = pthread.sem_close(self.handle)
+            assert res == 0, "Issue while closing semaphores"
+        except AttributeError:
+            pass
+
+    def _is_mine(self):
+        return self.count > 0 and get_ident() == self.ident
+
+    def acquire(self, block=True, timeout=None):
+        if self.kind == RECURSIVE_MUTEX and self._is_mine():
+            self.count += 1
+            return True
+
+        if block and timeout is None:
+            res = pthread.sem_wait(self.handle)
+        elif not block or timeout <= 0:
+            res = pthread.sem_trywait(self.handle)
+        else:
+            res = _sem_timedwait(self.handle, timeout)
+        if res < 0:
+            e = ctypes.get_errno()
+            if e == errno.EINTR:
+                return None
+            elif e in [errno.EAGAIN, errno.ETIMEDOUT]:
+                return False
+            raiseFromErrno()
+        self.count += 1
+        self.ident = get_ident()
+        return True
+
+    def release(self):
+        if self.kind == RECURSIVE_MUTEX:
+            assert self._is_mine(), (
+                "attempt to release recursive lock not owned by thread")
+            if self.count > 1:
+                self.count -= 1
+                return
+            assert self.count == 1
+        else:
+            if sys.platform == 'darwin':
+                # Handle broken get_value for mac ==> only Lock will work
+                # as sem_get_value do not work properly
+                if self.maxvalue == 1:
+                    if pthread.sem_trywait(self.handle) < 0:
+                        e = ctypes.get_errno()
+                        if e != errno.EAGAIN:
+                            raise OSError(e, errno.errorcode[e])
+                    else:
+                        if pthread.sem_post(self.handle) < 0:
+                            raiseFromErrno()
+                        else:
+                            raise ValueError(
+                                "semaphore or lock released too many times")
+                else:
+                    import warnings
+                    warnings.warn("semaphore are broken on OSX, release might "
+                                  "increase its maximal value", RuntimeWarning)
+            else:
+                value = self._get_value()
+                if value >= self.maxvalue:
+                    raise ValueError(
+                        "semaphore or lock released too many times")
+
+        if pthread.sem_post(self.handle) < 0:
+            raiseFromErrno()
+
+        self.count -= 1
+
+    def _get_value(self):
+        value = ctypes.pointer(ctypes.c_int(-1))
+        if pthread.sem_getvalue(self.handle, value) < 0:
+            raiseFromErrno()
+        return value.contents.value
+
+    def _count(self):
+        return self.count
+
+    def _is_zero(self):
+        if sys.platform == 'darwin':
+            # Handle broken get_value for mac ==> only Lock will work
+            # as sem_get_value do not work properly
+            if pthread.sem_trywait(self.handle) < 0:
+                e = ctypes.get_errno()
+                if e == errno.EAGAIN:
+                    return True
+                raise OSError(e, errno.errorcode[e])
+            else:
+                if pthread.sem_post(self.handle) < 0:
+                    raiseFromErrno()
+                return False
+        else:
+            value = ctypes.pointer(ctypes.c_int(-1))
+            if pthread.sem_getvalue(self.handle, value) < 0:
+                raiseFromErrno()
+            return value.contents.value == 0
+
+    def _after_fork(self):
+        self.count = 0
+
+    @staticmethod
+    def _rebuild(handle, kind, maxvalue, name):
+        self = SemLock.__new__(SemLock)
+        self.count = 0
+        self.ident = 0
+        self.kind = kind
+        self.maxvalue = maxvalue
+        self.name = name
+        self.handle = _sem_open(name.encode('ascii'))
+        return self
+
+
+def raiseFromErrno():
+    e = ctypes.get_errno()
+    raise OSError(e, errno.errorcode[e])

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/spawn.py

@@ -0,0 +1,232 @@
+###############################################################################
+# Prepares and processes the data to setup the new process environment
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+# adapted from multiprocessing/spawn.py (17/02/2017)
+#  * Improve logging data
+#
+import os
+import sys
+import runpy
+import types
+from multiprocessing import process, util
+
+
+if sys.platform != 'win32':
+    WINEXE = False
+    WINSERVICE = False
+else:
+    import msvcrt
+    from .reduction import duplicate
+    WINEXE = (sys.platform == 'win32' and getattr(sys, 'frozen', False))
+    WINSERVICE = sys.executable.lower().endswith("pythonservice.exe")
+
+if WINSERVICE:
+    _python_exe = os.path.join(sys.exec_prefix, 'python.exe')
+else:
+    _python_exe = sys.executable
+
+
+def get_executable():
+    return _python_exe
+
+
+def _check_not_importing_main():
+    if getattr(process.current_process(), '_inheriting', False):
+        raise RuntimeError('''
+        An attempt has been made to start a new process before the
+        current process has finished its bootstrapping phase.
+
+        This probably means that you are not using fork to start your
+        child processes and you have forgotten to use the proper idiom
+        in the main module:
+
+            if __name__ == '__main__':
+                freeze_support()
+                ...
+
+        The "freeze_support()" line can be omitted if the program
+        is not going to be frozen to produce an executable.''')
+
+
+def get_preparation_data(name, init_main_module=True):
+    '''
+    Return info about parent needed by child to unpickle process object
+    '''
+    _check_not_importing_main()
+    d = dict(
+        log_to_stderr=util._log_to_stderr,
+        authkey=bytes(process.current_process().authkey),
+        name=name,
+        sys_argv=sys.argv,
+        orig_dir=process.ORIGINAL_DIR,
+        dir=os.getcwd()
+    )
+
+    # Send sys_path and make sure the current directory will not be changed
+    sys_path = [p for p in sys.path]
+    try:
+        i = sys_path.index('')
+    except ValueError:
+        pass
+    else:
+        sys_path[i] = process.ORIGINAL_DIR
+    d['sys_path'] = sys_path
+
+    # Make sure to pass the information if the multiprocessing logger is active
+    if util._logger is not None:
+        d['log_level'] = util._logger.getEffectiveLevel()
+        if len(util._logger.handlers) > 0:
+            h = util._logger.handlers[0]
+            d['log_fmt'] = h.formatter._fmt
+
+    # Tell the child how to communicate with the resource_tracker
+    from .resource_tracker import _resource_tracker
+    _resource_tracker.ensure_running()
+    d["tracker_args"] = {"pid": _resource_tracker._pid}
+    if sys.platform == "win32":
+        child_w = duplicate(
+            msvcrt.get_osfhandle(_resource_tracker._fd), inheritable=True)
+        d["tracker_args"]["fh"] = child_w
+    else:
+        d["tracker_args"]["fd"] = _resource_tracker._fd
+
+    # Figure out whether to initialise main in the subprocess as a module
+    # or through direct execution (or to leave it alone entirely)
+    if init_main_module:
+        main_module = sys.modules['__main__']
+        try:
+            main_mod_name = getattr(main_module.__spec__, "name", None)
+        except BaseException:
+            main_mod_name = None
+        if main_mod_name is not None:
+            d['init_main_from_name'] = main_mod_name
+        elif sys.platform != 'win32' or (not WINEXE and not WINSERVICE):
+            main_path = getattr(main_module, '__file__', None)
+            if main_path is not None:
+                if (not os.path.isabs(main_path) and
+                        process.ORIGINAL_DIR is not None):
+                    main_path = os.path.join(process.ORIGINAL_DIR, main_path)
+                d['init_main_from_path'] = os.path.normpath(main_path)
+                # Compat for python2.7
+                d['main_path'] = d['init_main_from_path']
+
+    return d
+
+
+#
+# Prepare current process
+#
+old_main_modules = []
+
+
+def prepare(data):
+    '''
+    Try to get current process ready to unpickle process object
+    '''
+    if 'name' in data:
+        process.current_process().name = data['name']
+
+    if 'authkey' in data:
+        process.current_process().authkey = data['authkey']
+
+    if 'log_to_stderr' in data and data['log_to_stderr']:
+        util.log_to_stderr()
+
+    if 'log_level' in data:
+        util.get_logger().setLevel(data['log_level'])
+
+    if 'log_fmt' in data:
+        import logging
+        util.get_logger().handlers[0].setFormatter(
+            logging.Formatter(data['log_fmt'])
+        )
+
+    if 'sys_path' in data:
+        sys.path = data['sys_path']
+
+    if 'sys_argv' in data:
+        sys.argv = data['sys_argv']
+
+    if 'dir' in data:
+        os.chdir(data['dir'])
+
+    if 'orig_dir' in data:
+        process.ORIGINAL_DIR = data['orig_dir']
+
+    if 'tracker_args' in data:
+        from .resource_tracker import _resource_tracker
+        _resource_tracker._pid = data["tracker_args"]['pid']
+        if sys.platform == 'win32':
+            handle = data["tracker_args"]["fh"]
+            _resource_tracker._fd = msvcrt.open_osfhandle(handle, 0)
+        else:
+            _resource_tracker._fd = data["tracker_args"]["fd"]
+
+    if 'init_main_from_name' in data:
+        _fixup_main_from_name(data['init_main_from_name'])
+    elif 'init_main_from_path' in data:
+        _fixup_main_from_path(data['init_main_from_path'])
+
+
+# Multiprocessing module helpers to fix up the main module in
+# spawned subprocesses
+def _fixup_main_from_name(mod_name):
+    # __main__.py files for packages, directories, zip archives, etc, run
+    # their "main only" code unconditionally, so we don't even try to
+    # populate anything in __main__, nor do we make any changes to
+    # __main__ attributes
+    current_main = sys.modules['__main__']
+    if mod_name == "__main__" or mod_name.endswith(".__main__"):
+        return
+
+    # If this process was forked, __main__ may already be populated
+    if getattr(current_main.__spec__, "name", None) == mod_name:
+        return
+
+    # Otherwise, __main__ may contain some non-main code where we need to
+    # support unpickling it properly. We rerun it as __mp_main__ and make
+    # the normal __main__ an alias to that
+    old_main_modules.append(current_main)
+    main_module = types.ModuleType("__mp_main__")
+    main_content = runpy.run_module(mod_name,
+                                    run_name="__mp_main__",
+                                    alter_sys=True)
+    main_module.__dict__.update(main_content)
+    sys.modules['__main__'] = sys.modules['__mp_main__'] = main_module
+
+
+def _fixup_main_from_path(main_path):
+    # If this process was forked, __main__ may already be populated
+    current_main = sys.modules['__main__']
+
+    # Unfortunately, the main ipython launch script historically had no
+    # "if __name__ == '__main__'" guard, so we work around that
+    # by treating it like a __main__.py file
+    # See https://github.com/ipython/ipython/issues/4698
+    main_name = os.path.splitext(os.path.basename(main_path))[0]
+    if main_name == 'ipython':
+        return
+
+    # Otherwise, if __file__ already has the setting we expect,
+    # there's nothing more to do
+    if getattr(current_main, '__file__', None) == main_path:
+        return
+
+    # If the parent process has sent a path through rather than a module
+    # name we assume it is an executable script that may contain
+    # non-main code that needs to be executed
+    old_main_modules.append(current_main)
+    main_module = types.ModuleType("__mp_main__")
+    main_content = runpy.run_path(main_path,
+                                  run_name="__mp_main__")
+    main_module.__dict__.update(main_content)
+    sys.modules['__main__'] = sys.modules['__mp_main__'] = main_module
+
+
+def import_main_path(main_path):
+    '''
+    Set sys.modules['__main__'] to module at main_path
+    '''
+    _fixup_main_from_path(main_path)

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/synchronize.py

@@ -0,0 +1,381 @@
+###############################################################################
+# Synchronization primitives based on our SemLock implementation
+#
+# author: Thomas Moreau and Olivier Grisel
+#
+# adapted from multiprocessing/synchronize.py (17/02/2017)
+#  * Remove ctx argument for compatibility reason
+#  * Implementation of Condition/Event are necessary for compatibility
+#    with python2.7/3.3, Barrier should be reimplemented to for those
+#    version (but it is not used in loky).
+#
+
+import os
+import sys
+import tempfile
+import threading
+import _multiprocessing
+from time import time as _time
+
+from .context import assert_spawning
+from . import resource_tracker
+from multiprocessing import process
+from multiprocessing import util
+
+__all__ = [
+    'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Condition', 'Event'
+    ]
+# Try to import the mp.synchronize module cleanly, if it fails
+# raise ImportError for platforms lacking a working sem_open implementation.
+# See issue 3770
+try:
+    if sys.version_info < (3, 4):
+        from .semlock import SemLock as _SemLock
+        from .semlock import sem_unlink
+    else:
+        from _multiprocessing import SemLock as _SemLock
+        from _multiprocessing import sem_unlink
+except (ImportError):
+    raise ImportError("This platform lacks a functioning sem_open" +
+                      " implementation, therefore, the required" +
+                      " synchronization primitives needed will not" +
+                      " function, see issue 3770.")
+
+if sys.version_info[:2] < (3, 3):
+    FileExistsError = OSError
+
+#
+# Constants
+#
+
+RECURSIVE_MUTEX, SEMAPHORE = list(range(2))
+SEM_VALUE_MAX = _multiprocessing.SemLock.SEM_VALUE_MAX
+
+
+#
+# Base class for semaphores and mutexes; wraps `_multiprocessing.SemLock`
+#
+
+class SemLock(object):
+
+    _rand = tempfile._RandomNameSequence()
+
+    def __init__(self, kind, value, maxvalue):
+        # unlink_now is only used on win32 or when we are using fork.
+        unlink_now = False
+        for i in range(100):
+            try:
+                self._semlock = _SemLock(
+                    kind, value, maxvalue, SemLock._make_name(),
+                    unlink_now)
+            except FileExistsError:  # pragma: no cover
+                pass
+            else:
+                break
+        else:  # pragma: no cover
+            raise FileExistsError('cannot find name for semaphore')
+
+        util.debug('created semlock with handle %s and name "%s"'
+                   % (self._semlock.handle, self._semlock.name))
+
+        self._make_methods()
+
+        def _after_fork(obj):
+            obj._semlock._after_fork()
+
+        util.register_after_fork(self, _after_fork)
+
+        # When the object is garbage collected or the
+        # process shuts down we unlink the semaphore name
+        resource_tracker.register(self._semlock.name, "semlock")
+        util.Finalize(self, SemLock._cleanup, (self._semlock.name,),
+                      exitpriority=0)
+
+    @staticmethod
+    def _cleanup(name):
+        sem_unlink(name)
+        resource_tracker.unregister(name, "semlock")
+
+    def _make_methods(self):
+        self.acquire = self._semlock.acquire
+        self.release = self._semlock.release
+
+    def __enter__(self):
+        return self._semlock.acquire()
+
+    def __exit__(self, *args):
+        return self._semlock.release()
+
+    def __getstate__(self):
+        assert_spawning(self)
+        sl = self._semlock
+        h = sl.handle
+        return (h, sl.kind, sl.maxvalue, sl.name)
+
+    def __setstate__(self, state):
+        self._semlock = _SemLock._rebuild(*state)
+        util.debug('recreated blocker with handle %r and name "%s"'
+                   % (state[0], state[3]))
+        self._make_methods()
+
+    @staticmethod
+    def _make_name():
+        # OSX does not support long names for semaphores
+        return '/loky-%i-%s' % (os.getpid(), next(SemLock._rand))
+
+
+#
+# Semaphore
+#
+
+class Semaphore(SemLock):
+
+    def __init__(self, value=1):
+        SemLock.__init__(self, SEMAPHORE, value, SEM_VALUE_MAX)
+
+    def get_value(self):
+        if sys.platform == 'darwin':
+            raise NotImplementedError("OSX does not implement sem_getvalue")
+        return self._semlock._get_value()
+
+    def __repr__(self):
+        try:
+            value = self._semlock._get_value()
+        except Exception:
+            value = 'unknown'
+        return '<%s(value=%s)>' % (self.__class__.__name__, value)
+
+
+#
+# Bounded semaphore
+#
+
+class BoundedSemaphore(Semaphore):
+
+    def __init__(self, value=1):
+        SemLock.__init__(self, SEMAPHORE, value, value)
+
+    def __repr__(self):
+        try:
+            value = self._semlock._get_value()
+        except Exception:
+            value = 'unknown'
+        return '<%s(value=%s, maxvalue=%s)>' % \
+               (self.__class__.__name__, value, self._semlock.maxvalue)
+
+
+#
+# Non-recursive lock
+#
+
+class Lock(SemLock):
+
+    def __init__(self):
+        super(Lock, self).__init__(SEMAPHORE, 1, 1)
+
+    def __repr__(self):
+        try:
+            if self._semlock._is_mine():
+                name = process.current_process().name
+                if threading.current_thread().name != 'MainThread':
+                    name += '|' + threading.current_thread().name
+            elif self._semlock._get_value() == 1:
+                name = 'None'
+            elif self._semlock._count() > 0:
+                name = 'SomeOtherThread'
+            else:
+                name = 'SomeOtherProcess'
+        except Exception:
+            name = 'unknown'
+        return '<%s(owner=%s)>' % (self.__class__.__name__, name)
+
+
+#
+# Recursive lock
+#
+
+class RLock(SemLock):
+
+    def __init__(self):
+        super(RLock, self).__init__(RECURSIVE_MUTEX, 1, 1)
+
+    def __repr__(self):
+        try:
+            if self._semlock._is_mine():
+                name = process.current_process().name
+                if threading.current_thread().name != 'MainThread':
+                    name += '|' + threading.current_thread().name
+                count = self._semlock._count()
+            elif self._semlock._get_value() == 1:
+                name, count = 'None', 0
+            elif self._semlock._count() > 0:
+                name, count = 'SomeOtherThread', 'nonzero'
+            else:
+                name, count = 'SomeOtherProcess', 'nonzero'
+        except Exception:
+            name, count = 'unknown', 'unknown'
+        return '<%s(%s, %s)>' % (self.__class__.__name__, name, count)
+
+
+#
+# Condition variable
+#
+
+class Condition(object):
+
+    def __init__(self, lock=None):
+        self._lock = lock or RLock()
+        self._sleeping_count = Semaphore(0)
+        self._woken_count = Semaphore(0)
+        self._wait_semaphore = Semaphore(0)
+        self._make_methods()
+
+    def __getstate__(self):
+        assert_spawning(self)
+        return (self._lock, self._sleeping_count,
+                self._woken_count, self._wait_semaphore)
+
+    def __setstate__(self, state):
+        (self._lock, self._sleeping_count,
+         self._woken_count, self._wait_semaphore) = state
+        self._make_methods()
+
+    def __enter__(self):
+        return self._lock.__enter__()
+
+    def __exit__(self, *args):
+        return self._lock.__exit__(*args)
+
+    def _make_methods(self):
+        self.acquire = self._lock.acquire
+        self.release = self._lock.release
+
+    def __repr__(self):
+        try:
+            num_waiters = (self._sleeping_count._semlock._get_value() -
+                           self._woken_count._semlock._get_value())
+        except Exception:
+            num_waiters = 'unknown'
+        return '<%s(%s, %s)>' % (self.__class__.__name__,
+                                 self._lock, num_waiters)
+
+    def wait(self, timeout=None):
+        assert self._lock._semlock._is_mine(), \
+               'must acquire() condition before using wait()'
+
+        # indicate that this thread is going to sleep
+        self._sleeping_count.release()
+
+        # release lock
+        count = self._lock._semlock._count()
+        for i in range(count):
+            self._lock.release()
+
+        try:
+            # wait for notification or timeout
+            return self._wait_semaphore.acquire(True, timeout)
+        finally:
+            # indicate that this thread has woken
+            self._woken_count.release()
+
+            # reacquire lock
+            for i in range(count):
+                self._lock.acquire()
+
+    def notify(self):
+        assert self._lock._semlock._is_mine(), 'lock is not owned'
+        assert not self._wait_semaphore.acquire(False)
+
+        # to take account of timeouts since last notify() we subtract
+        # woken_count from sleeping_count and rezero woken_count
+        while self._woken_count.acquire(False):
+            res = self._sleeping_count.acquire(False)
+            assert res
+
+        if self._sleeping_count.acquire(False):  # try grabbing a sleeper
+            self._wait_semaphore.release()       # wake up one sleeper
+            self._woken_count.acquire()          # wait for the sleeper to wake
+
+            # rezero _wait_semaphore in case a timeout just happened
+            self._wait_semaphore.acquire(False)
+
+    def notify_all(self):
+        assert self._lock._semlock._is_mine(), 'lock is not owned'
+        assert not self._wait_semaphore.acquire(False)
+
+        # to take account of timeouts since last notify*() we subtract
+        # woken_count from sleeping_count and rezero woken_count
+        while self._woken_count.acquire(False):
+            res = self._sleeping_count.acquire(False)
+            assert res
+
+        sleepers = 0
+        while self._sleeping_count.acquire(False):
+            self._wait_semaphore.release()        # wake up one sleeper
+            sleepers += 1
+
+        if sleepers:
+            for i in range(sleepers):
+                self._woken_count.acquire()       # wait for a sleeper to wake
+
+            # rezero wait_semaphore in case some timeouts just happened
+            while self._wait_semaphore.acquire(False):
+                pass
+
+    def wait_for(self, predicate, timeout=None):
+        result = predicate()
+        if result:
+            return result
+        if timeout is not None:
+            endtime = _time() + timeout
+        else:
+            endtime = None
+            waittime = None
+        while not result:
+            if endtime is not None:
+                waittime = endtime - _time()
+                if waittime <= 0:
+                    break
+            self.wait(waittime)
+            result = predicate()
+        return result
+
+
+#
+# Event
+#
+
+class Event(object):
+
+    def __init__(self):
+        self._cond = Condition(Lock())
+        self._flag = Semaphore(0)
+
+    def is_set(self):
+        with self._cond:
+            if self._flag.acquire(False):
+                self._flag.release()
+                return True
+            return False
+
+    def set(self):
+        with self._cond:
+            self._flag.acquire(False)
+            self._flag.release()
+            self._cond.notify_all()
+
+    def clear(self):
+        with self._cond:
+            self._flag.acquire(False)
+
+    def wait(self, timeout=None):
+        with self._cond:
+            if self._flag.acquire(False):
+                self._flag.release()
+            else:
+                self._cond.wait(timeout)
+
+            if self._flag.acquire(False):
+                self._flag.release()
+                return True
+            return False

venv/lib/python3.8/site-packages/joblib/externals/loky/backend/utils.py

@@ -0,0 +1,172 @@
+import os
+import sys
+import time
+import errno
+import signal
+import warnings
+import threading
+import subprocess
+try:
+    import psutil
+except ImportError:
+    psutil = None
+
+
+WIN32 = sys.platform == "win32"
+
+
+def _flag_current_thread_clean_exit():
+    """Put a ``_clean_exit`` flag on the current thread"""
+    thread = threading.current_thread()
+    thread._clean_exit = True
+
+
+def recursive_terminate(process, use_psutil=True):
+    if use_psutil and psutil is not None:
+        _recursive_terminate_with_psutil(process)
+    else:
+        _recursive_terminate_without_psutil(process)
+
+
+def _recursive_terminate_with_psutil(process, retries=5):
+    try:
+        children = psutil.Process(process.pid).children(recursive=True)
+    except psutil.NoSuchProcess:
+        return
+
+    # Kill the children in reverse order to avoid killing the parents before
+    # the children in cases where there are more processes nested.
+    for child in children[::-1]:
+        try:
+            child.kill()
+        except psutil.NoSuchProcess:
+            pass
+
+    process.terminate()
+    process.join()
+
+
+def _recursive_terminate_without_psutil(process):
+    """Terminate a process and its descendants.
+    """
+    try:
+        _recursive_terminate(process.pid)
+    except OSError as e:
+        warnings.warn("Failed to kill subprocesses on this platform. Please"
+                      "install psutil: https://github.com/giampaolo/psutil")
+        # In case we cannot introspect the children, we fall back to the
+        # classic Process.terminate.
+        process.terminate()
+    process.join()
+
+
+def _recursive_terminate(pid):
+    """Recursively kill the descendants of a process before killing it.
+    """
+
+    if sys.platform == "win32":
+        # On windows, the taskkill function with option `/T` terminate a given
+        # process pid and its children.
+        try:
+            subprocess.check_output(
+                ["taskkill", "/F", "/T", "/PID", str(pid)],
+                stderr=None)
+        except subprocess.CalledProcessError as e:
+            # In windows, taskkill return 1 for permission denied and 128, 255
+            # for no process found.
+            if e.returncode not in [1, 128, 255]:
+                raise
+            elif e.returncode == 1:
+                # Try to kill the process without its descendants if taskkill
+                # was denied permission. If this fails too, with an error
+                # different from process not found, let the top level function
+                # raise a warning and retry to kill the process.
+                try:
+                    os.kill(pid, signal.SIGTERM)
+                except OSError as e:
+                    if e.errno != errno.ESRCH:
+                        raise
+
+    else:
+        try:
+            children_pids = subprocess.check_output(
+                ["pgrep", "-P", str(pid)],
+                stderr=None
+            )
+        except subprocess.CalledProcessError as e:
+            # `ps` returns 1 when no child process has been found
+            if e.returncode == 1:
+                children_pids = b''
+            else:
+                raise
+
+        # Decode the result, split the cpid and remove the trailing line
+        children_pids = children_pids.decode().split('\n')[:-1]
+        for cpid in children_pids:
+            cpid = int(cpid)
+            _recursive_terminate(cpid)
+
+        try:
+            os.kill(pid, signal.SIGTERM)
+        except OSError as e:
+            # if OSError is raised with [Errno 3] no such process, the process
+            # is already terminated, else, raise the error and let the top
+            # level function raise a warning and retry to kill the process.
+            if e.errno != errno.ESRCH:
+                raise
+
+
+def get_exitcodes_terminated_worker(processes):
+    """Return a formated string with the exitcodes of terminated workers.
+
+    If necessary, wait (up to .25s) for the system to correctly set the
+    exitcode of one terminated worker.
+    """
+    patience = 5
+
+    # Catch the exitcode of the terminated workers. There should at least be
+    # one. If not, wait a bit for the system to correctly set the exitcode of
+    # the terminated worker.
+    exitcodes = [p.exitcode for p in list(processes.values())
+                 if p.exitcode is not None]
+    while len(exitcodes) == 0 and patience > 0:
+        patience -= 1
+        exitcodes = [p.exitcode for p in list(processes.values())
+                     if p.exitcode is not None]
+        time.sleep(.05)
+
+    return _format_exitcodes(exitcodes)
+
+
+def _format_exitcodes(exitcodes):
+    """Format a list of exit code with names of the signals if possible"""
+    str_exitcodes = ["{}({})".format(_get_exitcode_name(e), e)
+                     for e in exitcodes if e is not None]
+    return "{" + ", ".join(str_exitcodes) + "}"
+
+
+def _get_exitcode_name(exitcode):
+    if sys.platform == "win32":
+        # The exitcode are unreliable  on windows (see bpo-31863).
+        # For this case, return UNKNOWN
+        return "UNKNOWN"
+
+    if exitcode < 0:
+        try:
+            import signal
+            if sys.version_info > (3, 5):
+                return signal.Signals(-exitcode).name
+
+            # construct an inverse lookup table
+            for v, k in signal.__dict__.items():
+                if (v.startswith('SIG') and not v.startswith('SIG_') and
+                        k == -exitcode):
+                        return v
+        except ValueError:
+            return "UNKNOWN"
+    elif exitcode != 255:
+        # The exitcode are unreliable on forkserver were 255 is always returned
+        # (see bpo-30589). For this case, return UNKNOWN
+        return "EXIT"
+
+    return "UNKNOWN"