1 files changed, 429 insertions, 0 deletions
diff --git a/Lib/multiprocessing/forking.py b/Lib/multiprocessing/forking.py
new file mode 100644
index 0000000..b14143b
--- /dev/null
+++ b/Lib/multiprocessing/forking.py
@@ -0,0 +1,429 @@
+#
+# 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']
+
+#
+# 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__
+            )
+
+#
+# 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 as 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 copyreg
+    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 dump, load, HIGHEST_PROTOCOL
+
+    #
+    #
+    #
+
+    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().get_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)
+
+    copyreg.pickle(Connection, reduce_connection)
+    copyreg.pickle(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().set_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 list(main_module.__dict__.values()):
+                try:
+                    if obj.__module__ == '__parents_main__':
+                        obj.__module__ = '__main__'
+                except Exception:
+                    pass