#

# Module for starting a process object using os.fork() or CreateProcess()

#

# multiprocessing/forking.py

#

# Copyright (c) 2006-2008, R Oudkerk --- see COPYING.txt

#

import os

import sys

import signal

from multiprocessing import util, process

__all__ = ['Popen', 'assert_spawning', 'exit', 'duplicate', 'close', 'ForkingPickler']

#

# Check that the current thread is spawning a child process

#

def assert_spawning(self):

    if not Popen.thread_is_spawning():

        raise RuntimeError(

            '%s objects should only be shared between processes'

            ' through inheritance' % type(self).__name__

            )

#

# Try making some callable types picklable

#

from pickle import Pickler

class ForkingPickler(Pickler):

    dispatch = Pickler.dispatch.copy()

    @classmethod

    def register(cls, type, reduce):

        def dispatcher(self, obj):

            rv = reduce(obj)

            self.save_reduce(obj=obj, *rv)

        cls.dispatch[type] = dispatcher

def _reduce_method(m):

    if m.im_self is None:

        return getattr, (m.im_class, m.im_func.func_name)

    else:

        return getattr, (m.im_self, m.im_func.func_name)

ForkingPickler.register(type(ForkingPickler.save), _reduce_method)

def _reduce_method_descriptor(m):

    return getattr, (m.__objclass__, m.__name__)

ForkingPickler.register(type(list.append), _reduce_method_descriptor)

ForkingPickler.register(type(int.__add__), _reduce_method_descriptor)

#def _reduce_builtin_function_or_method(m):

#    return getattr, (m.__self__, m.__name__)

#ForkingPickler.register(type(list().append), _reduce_builtin_function_or_method)

#ForkingPickler.register(type(int().__add__), _reduce_builtin_function_or_method)

try:

    from functools import partial

except ImportError:

    pass

else:

    def _reduce_partial(p):

        return _rebuild_partial, (p.func, p.args, p.keywords or {})

    def _rebuild_partial(func, args, keywords):

        return partial(func, *args, **keywords)

    ForkingPickler.register(partial, _reduce_partial)

#

# Unix

#

if sys.platform != 'win32':

    import time

    exit = os._exit

    duplicate = os.dup

    close = os.close

    #

    # We define a Popen class similar to the one from subprocess, but

    # whose constructor takes a process object as its argument.

    #

    class Popen(object):

        def __init__(self, process_obj):

            sys.stdout.flush()

            sys.stderr.flush()

            self.returncode = None

            self.pid = os.fork()

            if self.pid == 0:

                if 'random' in sys.modules:

                    import random

                    random.seed()

                code = process_obj._bootstrap()

                sys.stdout.flush()

                sys.stderr.flush()

                os._exit(code)

        def poll(self, flag=os.WNOHANG):

            if self.returncode is None:

                pid, sts = os.waitpid(self.pid, flag)

                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 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

        def terminate(self):

            if self.returncode is None:

                try:

                    os.kill(self.pid, signal.SIGTERM)

                except OSError, e:

                    if self.wait(timeout=0.1) is None:

                        raise

        @staticmethod

        def thread_is_spawning():

            return False

#

# Windows

#

else:

    import thread

    import msvcrt

    import _subprocess

    import time

    from ._multiprocessing import win32, Connection, PipeConnection

    from .util import Finalize

    #try:

    #    from cPickle import dump, load, HIGHEST_PROTOCOL

    #except ImportError:

    from pickle import load, HIGHEST_PROTOCOL

    def dump(obj, file, protocol=None):

        ForkingPickler(file, protocol).dump(obj)

    #

    #

    #

    TERMINATE = 0x10000

    WINEXE = (sys.platform == 'win32' and getattr(sys, 'frozen', False))

    exit = win32.ExitProcess

    close = win32.CloseHandle

    #

    # _python_exe is the assumed path to the python executable.

    # People embedding Python want to modify it.

    #

    if sys.executable.lower().endswith('pythonservice.exe'):

        _python_exe = os.path.join(sys.exec_prefix, 'python.exe')

    else:

        _python_exe = sys.executable

    def set_executable(exe):

        global _python_exe

        _python_exe = exe

    #

    #

    #

    def duplicate(handle, target_process=None, inheritable=False):

        if target_process is None:

            target_process = _subprocess.GetCurrentProcess()

        return _subprocess.DuplicateHandle(

            _subprocess.GetCurrentProcess(), handle, target_process,

            0, inheritable, _subprocess.DUPLICATE_SAME_ACCESS

            ).Detach()

    #

    # We define a Popen class similar to the one from subprocess, but

    # whose constructor takes a process object as its argument.

    #

    class Popen(object):

        '''

        Start a subprocess to run the code of a process object

        '''

        _tls = thread._local()

        def __init__(self, process_obj):

            # create pipe for communication with child

            rfd, wfd = os.pipe()

            # get handle for read end of the pipe and make it inheritable

            rhandle = duplicate(msvcrt.get_osfhandle(rfd), inheritable=True)

            os.close(rfd)

            # start process

            cmd = get_command_line() + [rhandle]

            cmd = ' '.join('"%s"' % x for x in cmd)

            hp, ht, pid, tid = _subprocess.CreateProcess(

                _python_exe, cmd, None, None, 1, 0, None, None, None

                )

            ht.Close()

            close(rhandle)

            # set attributes of self

            self.pid = pid

            self.returncode = None

            self._handle = hp

            # send information to child

            prep_data = get_preparation_data(process_obj._name)

            to_child = os.fdopen(wfd, 'wb')

            Popen._tls.process_handle = int(hp)

            try:

                dump(prep_data, to_child, HIGHEST_PROTOCOL)

                dump(process_obj, to_child, HIGHEST_PROTOCOL)

            finally:

                del Popen._tls.process_handle

                to_child.close()

        @staticmethod

        def thread_is_spawning():

            return getattr(Popen._tls, 'process_handle', None) is not None

        @staticmethod

        def duplicate_for_child(handle):

            return duplicate(handle, Popen._tls.process_handle)

        def wait(self, timeout=None):

            if self.returncode is None:

                if timeout is None:

                    msecs = _subprocess.INFINITE

                else:

                    msecs = max(0, int(timeout * 1000 + 0.5))

                res = _subprocess.WaitForSingleObject(int(self._handle), msecs)

                if res == _subprocess.WAIT_OBJECT_0:

                    code = _subprocess.GetExitCodeProcess(self._handle)

                    if code == TERMINATE:

                        code = -signal.SIGTERM

                    self.returncode = code

            return self.returncode

        def poll(self):

            return self.wait(timeout=0)

        def terminate(self):

            if self.returncode is None:

                try:

                    _subprocess.TerminateProcess(int(self._handle), TERMINATE)

                except WindowsError:

                    if self.wait(timeout=0.1) is None:

                        raise

    #

    #

    #

    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 freeze_support():

        '''

        Run code for process object if this in not the main process

        '''

        if is_forking(sys.argv):

            main()

            sys.exit()

    def get_command_line():

        '''

        Returns prefix of command line used for spawning a child process

        '''

        if process.current_process()._identity==() and is_forking(sys.argv):

            raise RuntimeError('''

            Attempt to start a new process before the current process

            has finished its bootstrapping phase.

            This probably means that you are on Windows 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 a Windows executable.''')

        if getattr(sys, 'frozen', False):

            return [sys.executable, '--multiprocessing-fork']

        else:

            prog = 'from multiprocessing.forking import main; main()'

            return [_python_exe, '-c', prog, '--multiprocessing-fork']

    def main():

        '''

        Run code specifed 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)

        prepare(preparation_data)

        self = load(from_parent)

        process.current_process()._inheriting = False

        from_parent.close()

        exitcode = self._bootstrap()

        exit(exitcode)

    def get_preparation_data(name):

        '''

        Return info about parent needed by child to unpickle process object

        '''

        from .util import _logger, _log_to_stderr

        d = dict(

            name=name,

            sys_path=sys.path,

            sys_argv=sys.argv,

            log_to_stderr=_log_to_stderr,

            orig_dir=process.ORIGINAL_DIR,

            authkey=process.current_process().authkey,

            )

        if _logger is not None:

            d['log_level'] = _logger.getEffectiveLevel()

        if not WINEXE:

            main_path = getattr(sys.modules['__main__'], '__file__', None)

            if not main_path and sys.argv[0] not in ('', '-c'):

                main_path = sys.argv[0]

            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['main_path'] = os.path.normpath(main_path)

        return d

    #

    # Make (Pipe)Connection picklable

    #

    def reduce_connection(conn):

        if not Popen.thread_is_spawning():

            raise RuntimeError(

                'By default %s objects can only be shared between processes\n'

                'using inheritance' % type(conn).__name__

                )

        return type(conn), (Popen.duplicate_for_child(conn.fileno()),

                            conn.readable, conn.writable)

    ForkingPickler.register(Connection, reduce_connection)

    ForkingPickler.register(PipeConnection, reduce_connection)

#

# Prepare current process

#

old_main_modules = []

def prepare(data):

    '''

    Try to get current process ready to unpickle process object

    '''

    old_main_modules.append(sys.modules['__main__'])

    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 '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 'main_path' in data:

        main_path = data['main_path']

        main_name = os.path.splitext(os.path.basename(main_path))[0]

        if main_name == '__init__':

            main_name = os.path.basename(os.path.dirname(main_path))

        if main_name != 'ipython':

            import imp

            if main_path is None:

                dirs = None

            elif os.path.basename(main_path).startswith('__init__.py'):

                dirs = [os.path.dirname(os.path.dirname(main_path))]

            else:

                dirs = [os.path.dirname(main_path)]

            assert main_name not in sys.modules, main_name

            file, path_name, etc = imp.find_module(main_name, dirs)

            try:

                # We would like to do "imp.load_module('__main__', ...)"

                # here.  However, that would cause 'if __name__ ==

                # "__main__"' clauses to be executed.

                main_module = imp.load_module(

                    '__parents_main__', file, path_name, etc

                    )

            finally:

                if file:

                    file.close()

            sys.modules['__main__'] = main_module

            main_module.__name__ = '__main__'

            # Try to make the potentially picklable objects in

            # sys.modules['__main__'] realize they are in the main

            # module -- somewhat ugly.

            for obj in main_module.__dict__.values():

                try:

                    if obj.__module__ == '__parents_main__':

                        obj.__module__ = '__main__'

                except Exception:

                    pass