--- loncom/lond	2014/06/29 03:22:43	1.511
+++ loncom/lond	2014/11/24 02:36:16	1.512
@@ -2,7 +2,7 @@
 # The LearningOnline Network
 # lond "LON Daemon" Server (port "LOND" 5663)
 #
-# $Id: lond,v 1.511 2014/06/29 03:22:43 raeburn Exp $
+# $Id: lond,v 1.512 2014/11/24 02:36:16 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -61,7 +61,7 @@ my $DEBUG = 0;		       # Non zero to ena
 my $status='';
 my $lastlog='';
 
-my $VERSION='$Revision: 1.511 $'; #' stupid emacs
+my $VERSION='$Revision: 1.512 $'; #' stupid emacs
 my $remoteVERSION;
 my $currenthostid="default";
 my $currentdomainid;
@@ -3322,6 +3322,9 @@ sub dump_with_regexp {
 #                          namespace   - Name of the database being modified
 #                          rid         - Resource keyword to modify.
 #                          what        - new value associated with rid.
+#                          laststore   - (optional) version=timestamp
+#                                        for most recent transaction for rid
+#                                        in namespace, when cstore was called
 #
 #    $client             - Socket open on the client.
 #
@@ -3330,23 +3333,45 @@ sub dump_with_regexp {
 #      1 (keep on processing).
 #  Side-Effects:
 #    Writes to the client
+#    Successful storage will cause either 'ok', or, if $laststore was included
+#    in the tail of the request, and the version number for the last transaction
+#    is larger than the version in $laststore, delay:$numtrans , where $numtrans
+#    is the number of store evevnts recorded for rid in namespace since
+#    lonnet::store() was called by the client.
+#
 sub store_handler {
     my ($cmd, $tail, $client) = @_;
  
     my $userinput = "$cmd:$tail";
-
-    my ($udom,$uname,$namespace,$rid,$what) =split(/:/,$tail);
+    chomp($tail);
+    my ($udom,$uname,$namespace,$rid,$what,$laststore) =split(/:/,$tail);
     if ($namespace ne 'roles') {
 
-	chomp($what);
 	my @pairs=split(/\&/,$what);
 	my $hashref  = &tie_user_hash($udom, $uname, $namespace,
 				       &GDBM_WRCREAT(), "S",
 				       "$rid:$what");
 	if ($hashref) {
 	    my $now = time;
-	    my @previouskeys=split(/&/,$hashref->{"keys:$rid"});
-	    my $key;
+            my $numtrans;
+            if ($laststore) {
+                my ($previousversion,$previoustime) = split(/\=/,$laststore);
+                my ($lastversion,$lasttime) = (0,0);
+                $lastversion = $hashref->{"version:$rid"};
+                if ($lastversion) {
+                    $lasttime = $hashref->{"$lastversion:$rid:timestamp"};
+                }
+                if (($previousversion) && ($previousversion !~ /\D/)) {
+                    if (($lastversion > $previousversion) && ($lasttime >= $previoustime)) {
+                        $numtrans = $lastversion - $previousversion;
+                    }
+                } elsif ($lastversion) {
+                    $numtrans = $lastversion;
+                }
+                if ($numtrans) {
+                    $numtrans =~ s/D//g;
+                }
+            }
 	    $hashref->{"version:$rid"}++;
 	    my $version=$hashref->{"version:$rid"};
 	    my $allkeys=''; 
@@ -3359,7 +3384,11 @@ sub store_handler {
 	    $allkeys.='timestamp';
 	    $hashref->{"$version:keys:$rid"}=$allkeys;
 	    if (&untie_user_hash($hashref)) {
-		&Reply($client, "ok\n", $userinput);
+                my $msg = 'ok';
+                if ($numtrans) {
+                    $msg = 'delay:'.$numtrans;
+                }
+		&Reply($client, "$msg\n", $userinput);
 	    } else {
 		&Failure($client, "error: ".($!+0)." untie(GDBM) Failed ".
 			"while attempting store\n", $userinput);