--- loncom/lond	2002/09/30 21:38:18	1.100
+++ loncom/lond	2002/10/07 13:50:36	1.102
@@ -2,7 +2,7 @@
 # The LearningOnline Network
 # lond "LON Daemon" Server (port "LOND" 5663)
 #
-# $Id: lond,v 1.100 2002/09/30 21:38:18 matthew Exp $
+# $Id: lond,v 1.102 2002/10/07 13:50:36 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -1015,6 +1015,10 @@ sub make_new_child {
 # ------------------------------------------------------------------- subscribe
                    } elsif ($userinput =~ /^sub/) {
 		       print $client &subscribe($userinput,$clientip);
+# ------------------------------------------------------------- current version
+                   } elsif ($userinput =~ /^currentversion/) {
+                       my ($cmd,$fname)=split(/:/,$userinput);
+		       print $client &currentversion($fname)."\n";
 # ------------------------------------------------------------------------- log
                    } elsif ($userinput =~ /^log/) {
                        my ($cmd,$udom,$uname,$what)=split(/:/,$userinput);
@@ -1647,12 +1651,68 @@ sub unsub {
     return $result;
 }
 
+sub currentversion {
+    my $fname=shift;
+    my $version=-1;
+    my $ulsdir='';
+    if ($fname=~/^(.+)\/[^\/]+$/) {
+       $ulsdir=$1;
+    }
+    $fname=~s/\.\d+\.(\w+(?:\.meta)*)$/\.$1/;
+    $fname=~s/\.(\w+(?:\.meta)*)$/\.\(\\d\+\)\.$1\$/;
+
+    if (-e $fname) { $version=1; }
+    if (-e $ulsdir) {
+       if(-d $ulsdir) {
+          if (opendir(LSDIR,$ulsdir)) {
+             while ($ulsfn=readdir(LSDIR)) {
+# see if this is a regular file (ignore links produced earlier)
+                 my $thisfile=$ulsdir.'/'.$ulsfn;
+                 unless (-l $thisfile) {
+		    if ($thisfile=~/$fname/) {
+		        if ($1>$version) { $version=$1; }
+                    }
+		 }
+             }
+             closedir(LSDIR);
+             $version++;
+          }
+      }
+   }
+   return $version;
+}
+
+sub thisversion {
+    my $fname=shift;
+    my $version=-1;
+    if ($fname=~/\.(\d+)\.\w+(?:\.meta)*$/) {
+	$version=$1;
+    }
+    return $version;
+}
+
 sub subscribe {
     my ($userinput,$clientip)=@_;
     my $result;
     my ($cmd,$fname)=split(/:/,$userinput);
     my $ownership=&ishome($fname);
     if ($ownership eq 'owner') {
+# explitly asking for the current version?
+        unless (-e $fname) {
+            my $currentversion=&currentversion($fname);
+	    if (&thisversion($fname)==$currentversion) {
+                if ($fname=~/^(.+)\.\d+\.(\w+(?:\.meta)*)$/) {
+		    my $root=$1;
+                    my $extension=$2;
+                    symlink($root.'.'.$extension,
+                            $root.'.'.$currentversion.'.'.$extension);
+                    unless ($extension=~/\.meta$/) {
+                       symlink($root.'.'.$extension.'.meta',
+                            $root.'.'.$currentversion.'.'.$extension.'.meta');
+		    }
+                }
+            }
+        }
 	if (-e $fname) {
 	    if (-d $fname) {
 		$result="directory\n";