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#!/usr/bin/env python3
# Copyright (c) 2011 Google Inc. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""These functions are executed via gyp-flock-tool when using the Makefile
generator. Used on systems that don't have a built-in flock."""
import fcntl
import os
import struct
import subprocess
import sys
def main(args):
executor = FlockTool()
executor.Dispatch(args)
class FlockTool:
"""This class emulates the 'flock' command."""
def Dispatch(self, args):
"""Dispatches a string command to a method."""
if len(args) < 1:
raise Exception("Not enough arguments")
method = "Exec%s" % self._CommandifyName(args[0])
getattr(self, method)(*args[1:])
def _CommandifyName(self, name_string):
"""Transforms a tool name like copy-info-plist to CopyInfoPlist"""
return name_string.title().replace("-", "")
def ExecFlock(self, lockfile, *cmd_list):
"""Emulates the most basic behavior of Linux's flock(1)."""
# Rely on exception handling to report errors.
# Note that the stock python on SunOS has a bug
# where fcntl.flock(fd, LOCK_EX) always fails
# with EBADF, that's why we use this F_SETLK
# hack instead.
fd = os.open(lockfile, os.O_WRONLY | os.O_NOCTTY | os.O_CREAT, 0o666)
if sys.platform.startswith("aix") or sys.platform == "os400":
# Python on AIX is compiled with LARGEFILE support, which changes the
# struct size.
op = struct.pack("hhIllqq", fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)
else:
op = struct.pack("hhllhhl", fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)
fcntl.fcntl(fd, fcntl.F_SETLK, op)
return subprocess.call(cmd_list)
if __name__ == "__main__":
sys.exit(main(sys.argv[1:]))
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