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