--- loncom/localize/lonlocal.pm	2009/05/04 21:44:00	1.58
+++ loncom/localize/lonlocal.pm	2009/05/06 19:25:49	1.59
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Localization routines
 #
-# $Id: lonlocal.pm,v 1.58 2009/05/04 21:44:00 lueken Exp $
+# $Id: lonlocal.pm,v 1.59 2009/05/06 19:25:49 droeschl Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -393,10 +393,8 @@ sub gettimezone {
     return 'local';
 }
 
-our $timezone_local;
-
 sub locallocaltime {
-    my ($thistime,$timezone,$datetime) = @_;
+    my ($thistime,$timezone) = @_;
 
     if (!defined($thistime) || $thistime eq '') {
 	return &mt('Never');
@@ -410,69 +408,16 @@ sub locallocaltime {
         return &mt('Never');
     }
 
-   my $dt;
-   my $convert_time;
+    my $dt = DateTime->from_epoch(epoch => $thistime)
+                     ->set_time_zone(gettimezone($timezone));
 
-   #### START # Speed up if this function is called often #### 
-   
-   # Is a $datetime parameter set?
-   if(defined($datetime)) {
-	# Check for an instance of a DateTime object
-   	if(!(defined $$datetime)) {
-		# No object, create one
-		$$datetime = DateTime->from_epoch(epoch => $thistime)
-       	                  ->set_time_zone(&gettimezone($timezone));
-		$dt = $$datetime;
-	   } else {
-		# If the return-value is "local", we have to convert it for DateTime	
-	
-		# Converts the "local"-String only once
-		if(!defined($timezone_local))	
-		{
-			$timezone_local = DateTime::TimeZone->new( name => gettimezone('local'))->name();
-		}
-
-		my $timezone_now;
-
-		if(gettimezone($timezone) == 'local')
-		{
-			$timezone_now = $timezone_local;
-		} else {
-			$timezone_now = gettimezone($timezone);
-		}
-
-		# Has the timezone changed?
-		if($timezone_now eq $$datetime->time_zone_short_name() ||
-		   $timezone_now eq $$datetime->time_zone_long_name())
-		{
-			# There is already an object (dereference)
-			$dt = $$datetime;
-		
-			# We need this as temporary value	
-			$convert_time = DateTime->from_epoch( epoch => $thistime );
-        	                                #->set_time_zone('floating');
- 
-			# Preventing a set_time_zone call (time consuming)	
-			# Using old instance of DateTime with timezone
-			$dt->set( year => $convert_time->year(),
-				  month => $convert_time->month(),
-				  day => $convert_time->day(),
-				  hour => $convert_time->hour(),
-				  minute => $convert_time->minute(),
-				  second => $convert_time->second() );
-   		} else {
-			# The timezone has changed since last time
-			$$datetime = DateTime->from_epoch(epoch => $thistime)
-                          ->set_time_zone(&gettimezone($timezone));
-			$dt = $$datetime;
-		} 
-	}
-   } else {
-	# There is no $datetime parameter
-	$dt = DateTime->from_epoch(epoch => $thistime)
-                      ->set_time_zone(&gettimezone($timezone));
-   }
-   #### END # Speed up if this function is called often ####
+    # TimeZone tries to determine the 'local' timezone from $ENV{TZ} if this
+    # fails it searches through various system files. Under certain
+    # circumstances this is an extremly expensive operation.
+    # So after the first run we store the timezone in $ENV{TZ} to significantly
+    # speed up future lookups. 
+    $ENV{TZ} = $dt->time_zone()->name() 
+        if (! $ENV{TZ} && gettimezone($timezone) eq 'local');
 
     if ((&current_language=~/^en/) || (!$lh)) {