gecko-dev/config/build-list.pl

#!env perl

#
# The contents of this file are subject to the Mozilla Public
# License Version 1.1 (the "License"); you may not use this file
# except in compliance with the License. You may obtain a copy of
# the License at http://www.mozilla.org/MPL/
#
# Software distributed under the License is distributed on an "AS
# IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
# implied. See the License for the specific language governing
# rights and limitations under the License.
#
# The Original Code is mozilla.org code.
#
# The Initial Developer of the Original Code is Netscape
# Communications Corporation.  Portions created by Netscape are
# Copyright (C) 2001 Netscape Communications Corporation. All
# Rights Reserved.
#
# Contributor(s): 
#	Christopher Seawood <cls@seawood.org>

#
# A generic script to add entries to a file 
# if the entry does not already exist
# 
# Usage: $0 [-l] <filename> <entry>
#
#   -l do not attempt flock the file.

use Fcntl qw(:DEFAULT :flock);
use Getopt::Std;

sub usage() {
    print "$0 [-l] <filename> <entry>\n";
    exit(1);
}

$nofilelocks = 0;

getopts("l");

$nofilelocks = 1 if defined($::opt_l);

$file = shift;
$entry = shift;

# touch the file if it doesn't exist
if ( ! -e "$file") {
    $now = time;
    utime $now, $now, $file;
}

# This needs to be atomic
open(OUT, ">>$file") || die ("$file: $!\n");
flock(OUT, LOCK_EX) unless $nofilelocks;
open(RES, "grep -c '^$entry\$' $file |") or $err = $!;
if ($err) {
	flock(OUT,LOCK_UN) unless $nofilelocks;
	die ("grep: $err\n");
}
chomp($val = <RES>);
close(RES);
if (!$val) {
    print OUT "$entry\n";
}
flock(OUT, LOCK_UN) unless $nofilelocks;
close(OUT);

exit(0);