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1#!/usr/bin/env python32# Copyright (c) 2011 Google Inc. All rights reserved.3# Use of this source code is governed by a BSD-style license that can be4# found in the LICENSE file.5 6"""These functions are executed via gyp-flock-tool when using the Makefile7generator.  Used on systems that don't have a built-in flock."""8 9import fcntl10import os11import struct12import subprocess13import sys14 15 16def main(args):17    executor = FlockTool()18    executor.Dispatch(args)19 20 21class FlockTool:22    """This class emulates the 'flock' command."""23 24    def Dispatch(self, args):25        """Dispatches a string command to a method."""26        if len(args) < 1:27            raise Exception("Not enough arguments")28 29        method = "Exec%s" % self._CommandifyName(args[0])30        getattr(self, method)(*args[1:])31 32    def _CommandifyName(self, name_string):33        """Transforms a tool name like copy-info-plist to CopyInfoPlist"""34        return name_string.title().replace("-", "")35 36    def ExecFlock(self, lockfile, *cmd_list):37        """Emulates the most basic behavior of Linux's flock(1)."""38        # Rely on exception handling to report errors.39        # Note that the stock python on SunOS has a bug40        # where fcntl.flock(fd, LOCK_EX) always fails41        # with EBADF, that's why we use this F_SETLK42        # hack instead.43        fd = os.open(lockfile, os.O_WRONLY | os.O_NOCTTY | os.O_CREAT, 0o666)44        if sys.platform.startswith("aix") or sys.platform == "os400":45            # Python on AIX is compiled with LARGEFILE support, which changes the46            # struct size.47            op = struct.pack("hhIllqq", fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)48        else:49            op = struct.pack("hhllhhl", fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)50        fcntl.fcntl(fd, fcntl.F_SETLK, op)51        return subprocess.call(cmd_list)52 53 54if __name__ == "__main__":55    sys.exit(main(sys.argv[1:]))56