Simple script to add entry to file if the entry doesn't already exist. Uses flock () . Needed for generating final link list for static builds. bug #46775

config/build-list.pl

@@ -0,0 +1,61 @@
+#!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 <filename> <entry>
+
+use Fcntl qw(:DEFAULT :flock);
+
+sub usage() {
+    print "$0 <filename> <entry>\n";
+    exit(1);
+}
+
+if ($#ARGV != 1) {
+    usage();
+}
+
+$file = shift;
+$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: $!\n");
+flock(OUT, LOCK_EX);
+system("grep -c '^$entry\$' $file >/dev/null");
+$exit_value = $? >> 8;
+if ($exit_value) {
+    print OUT "$entry\n";
+}
+flock(OUT, LOCK_UN);
+close(OUT);
+
+exit(0);