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Diffstat (limited to 'lib/python2.7/multiprocessing/process.py')
-rw-r--r-- | lib/python2.7/multiprocessing/process.py | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/lib/python2.7/multiprocessing/process.py b/lib/python2.7/multiprocessing/process.py new file mode 100644 index 0000000..44c1e44 --- /dev/null +++ b/lib/python2.7/multiprocessing/process.py @@ -0,0 +1,323 @@ +# +# Module providing the `Process` class which emulates `threading.Thread` +# +# multiprocessing/process.py +# +# Copyright (c) 2006-2008, R Oudkerk +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions +# are met: +# +# 1. Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# 2. Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# 3. Neither the name of author nor the names of any contributors may be +# used to endorse or promote products derived from this software +# without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +# SUCH DAMAGE. +# + +__all__ = ['Process', 'current_process', 'active_children'] + +# +# Imports +# + +import os +import sys +import signal +import itertools + +# +# +# + +try: + ORIGINAL_DIR = os.path.abspath(os.getcwd()) +except OSError: + ORIGINAL_DIR = None + +# +# Public functions +# + +def current_process(): + ''' + Return process object representing the current process + ''' + return _current_process + +def active_children(): + ''' + Return list of process objects corresponding to live child processes + ''' + _cleanup() + return list(_current_process._children) + +# +# +# + +def _cleanup(): + # check for processes which have finished + for p in list(_current_process._children): + if p._popen.poll() is not None: + _current_process._children.discard(p) + +# +# The `Process` class +# + +class Process(object): + ''' + Process objects represent activity that is run in a separate process + + The class is analagous to `threading.Thread` + ''' + _Popen = None + + def __init__(self, group=None, target=None, name=None, args=(), kwargs={}): + assert group is None, 'group argument must be None for now' + count = _current_process._counter.next() + self._identity = _current_process._identity + (count,) + self._authkey = _current_process._authkey + self._daemonic = _current_process._daemonic + self._tempdir = _current_process._tempdir + self._parent_pid = os.getpid() + self._popen = None + self._target = target + self._args = tuple(args) + self._kwargs = dict(kwargs) + self._name = name or type(self).__name__ + '-' + \ + ':'.join(str(i) for i in self._identity) + + def run(self): + ''' + Method to be run in sub-process; can be overridden in sub-class + ''' + if self._target: + self._target(*self._args, **self._kwargs) + + def start(self): + ''' + Start child process + ''' + 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' + assert not _current_process._daemonic, \ + 'daemonic processes are not allowed to have children' + _cleanup() + if self._Popen is not None: + Popen = self._Popen + else: + from .forking import Popen + self._popen = Popen(self) + _current_process._children.add(self) + + def terminate(self): + ''' + Terminate process; sends SIGTERM signal or uses TerminateProcess() + ''' + self._popen.terminate() + + def join(self, timeout=None): + ''' + Wait until child process terminates + ''' + assert self._parent_pid == os.getpid(), 'can only join a child process' + assert self._popen is not None, 'can only join a started process' + res = self._popen.wait(timeout) + if res is not None: + _current_process._children.discard(self) + + def is_alive(self): + ''' + Return whether process is alive + ''' + if self is _current_process: + return True + assert self._parent_pid == os.getpid(), 'can only test a child process' + if self._popen is None: + return False + self._popen.poll() + return self._popen.returncode is None + + @property + def name(self): + return self._name + + @name.setter + def name(self, name): + assert isinstance(name, basestring), 'name must be a string' + self._name = name + + @property + def daemon(self): + ''' + Return whether process is a daemon + ''' + return self._daemonic + + @daemon.setter + def daemon(self, daemonic): + ''' + Set whether process is a daemon + ''' + assert self._popen is None, 'process has already started' + self._daemonic = daemonic + + @property + def authkey(self): + return self._authkey + + @authkey.setter + def authkey(self, authkey): + ''' + Set authorization key of process + ''' + self._authkey = AuthenticationString(authkey) + + @property + def exitcode(self): + ''' + Return exit code of process or `None` if it has yet to stop + ''' + if self._popen is None: + return self._popen + return self._popen.poll() + + @property + def ident(self): + ''' + Return identifier (PID) of process or `None` if it has yet to start + ''' + if self is _current_process: + return os.getpid() + else: + return self._popen and self._popen.pid + + pid = ident + + def __repr__(self): + if self is _current_process: + status = 'started' + elif self._parent_pid != os.getpid(): + status = 'unknown' + elif self._popen is None: + status = 'initial' + else: + if self._popen.poll() is not None: + status = self.exitcode + else: + status = 'started' + + if type(status) is int: + if status == 0: + status = 'stopped' + else: + status = 'stopped[%s]' % _exitcode_to_name.get(status, status) + + return '<%s(%s, %s%s)>' % (type(self).__name__, self._name, + status, self._daemonic and ' daemon' or '') + + ## + + def _bootstrap(self): + from . import util + global _current_process + + try: + self._children = set() + self._counter = itertools.count(1) + try: + sys.stdin.close() + sys.stdin = open(os.devnull) + except (OSError, ValueError): + pass + _current_process = self + util._finalizer_registry.clear() + util._run_after_forkers() + util.info('child process calling self.run()') + try: + self.run() + exitcode = 0 + finally: + util._exit_function() + except SystemExit, e: + if not e.args: + exitcode = 1 + elif isinstance(e.args[0], int): + exitcode = e.args[0] + else: + sys.stderr.write(str(e.args[0]) + '\n') + sys.stderr.flush() + exitcode = 1 + except: + exitcode = 1 + import traceback + sys.stderr.write('Process %s:\n' % self.name) + sys.stderr.flush() + traceback.print_exc() + + util.info('process exiting with exitcode %d' % exitcode) + return exitcode + +# +# We subclass bytes to avoid accidental transmission of auth keys over network +# + +class AuthenticationString(bytes): + def __reduce__(self): + from .forking import Popen + if not Popen.thread_is_spawning(): + raise TypeError( + 'Pickling an AuthenticationString object is ' + 'disallowed for security reasons' + ) + return AuthenticationString, (bytes(self),) + +# +# Create object representing the main process +# + +class _MainProcess(Process): + + def __init__(self): + self._identity = () + self._daemonic = False + self._name = 'MainProcess' + self._parent_pid = None + self._popen = None + self._counter = itertools.count(1) + self._children = set() + self._authkey = AuthenticationString(os.urandom(32)) + self._tempdir = None + +_current_process = _MainProcess() +del _MainProcess + +# +# Give names to some return codes +# + +_exitcode_to_name = {} + +for name, signum in signal.__dict__.items(): + if name[:3]=='SIG' and '_' not in name: + _exitcode_to_name[-signum] = name |