Tools/Scripts/webkitpy/common/multiprocessing_bootstrap.py

# Copyright (c) 2011 Google Inc. All rights reserved.
# Copyright (C) 2010 Chris Jerdonek (cjerdonek@webkit.org)
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"""In order for the multiprocessing module to spawn children correctly on
Windows, we need to be running a Python module that can be imported
(which means a file in sys.path that ends in .py). In addition, we need to
ensure that sys.path / PYTHONPATH is set and propagating correctly.

This module enforces that."""

import os
import subprocess
import sys


def run(*parts):
    up = os.path.dirname
    script_dir = up(up(up(os.path.abspath(__file__))))
    env = os.environ
    if 'PYTHONPATH' in env:
        if script_dir not in env['PYTHONPATH']:
            env['PYTHONPATH'] = env['PYTHONPATH'] + os.pathsep + script_dir
    else:
        env['PYTHONPATH'] = script_dir
    module_path = os.path.join(script_dir, *parts)
    cmd = [sys.executable, module_path] + sys.argv[1:]

    proc = subprocess.Popen(cmd, env=env)
    try:
        proc.wait()
    except KeyboardInterrupt:
        # We need a second wait in order to make sure the subprocess exits fully.
        # FIXME: It would be nice if we could put a timeout on this.
        proc.wait()
    sys.exit(proc.returncode)