--- loncom/interface/loncoursedata.pm	2003/02/13 22:52:48	1.46
+++ loncom/interface/loncoursedata.pm	2003/02/14 21:02:05	1.47
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # (Publication Handler
 #
-# $Id: loncoursedata.pm,v 1.46 2003/02/13 22:52:48 matthew Exp $
+# $Id: loncoursedata.pm,v 1.47 2003/02/14 21:02:05 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -1498,11 +1498,36 @@ sub CheckForResidualDownload {
 
 =pod
 
+=item &make_into_hash($values);
+
+Returns a reference to a hash as described by $values.  $values is
+assumed to be the result of 
+    join(':',map {&Apache::lonnet::escape($_)} %orighash;
+
+This is a helper function for get_current_state.
+
+=cut
+
+################################################
+################################################
+sub make_into_hash {
+    my $values = shift;
+    my %tmp = map { &Apache::lonnet::unescape($_); }
+                                           split(':',$values);
+    return \%tmp;
+}
+
+
+################################################
+################################################
+
+=pod
+
 =item &get_current_state($sname,$sdom,$symb,$courseid);
 
-Retrive the current status of a students performance.  $sname and
+Retrieve the current status of a students performance.  $sname and
 $sdom are the only required parameters.  If $symb is undef the results
-of a &Apache::lonnet::currentdump() will be returned.  
+of an &Apache::lonnet::currentdump() will be returned.  
 If $courseid is undef it will be retrieved from the environment.
 
 The return structure is based on &Apache::lonnet::currentdump.  If
@@ -1520,8 +1545,6 @@ If $symb is specified, a hash of
 )
 is returned.
 
-Eventually this routine will cache the results locally.
-
 If no data is found for $symb, or if the student has not performance data,
 an empty list is returned.
 
@@ -1529,23 +1552,95 @@ an empty list is returned.
 
 ################################################
 ################################################
-
 sub get_current_state {
-    my ($sname,$sdom,$symb,$courseid)=@_;
-    return undef if (! defined($sname) || ! defined($sdom));
+    my ($sname,$sdom,$symb,$courseid,$forcedownload)=@_;
+    return () if (! defined($sname) || ! defined($sdom));
+    #
     $courseid = $ENV{'request.course.id'} if (! defined($courseid));
-    # For a first pass, just get a currentdump and return the requested
-    # results
-    my @tmp = &Apache::lonnet::currentdump($courseid,$sdom,$sname);
-    if (! ((scalar(@tmp) > 0) && ($tmp[0] !~ /^error:/)) ) {
-        &Apache::lonnet::logthis('error getting data for '.$sname.':'.$sdom.
-                                 'in course '.$courseid);
-        return ();
+    #
+    my $cachefilename = $Apache::lonnet::tmpdir.$ENV{'user.name'}.'_'.
+                                                $ENV{'user.domain'}.'_'.
+                                                $courseid.'_student_data.db';
+    my %cache;
+    #
+    my %student_data; # return values go here
+    #
+    my $updatetime = 0;
+    my $key = &Apache::lonnet::escape($sname).':'.
+              &Apache::lonnet::escape($sdom).':';
+    # Open the cache file
+    if (tie(%cache,'GDBM_File',$cachefilename,&GDBM_READER(),0640)) {
+        if (exists($cache{$key.'time'})) {
+            $updatetime = $cache{$key.'time'};
+#            &Apache::lonnet::logthis('got updatetime of '.$updatetime);
+        }
+        untie(%cache);
+    }
+    # timestamp/devalidation 
+    my $modifiedtime = 1;
+    # Take whatever steps are neccessary at this point to give $modifiedtime a
+    # new value
+    #
+    if (($updatetime < $modifiedtime) || 
+        (defined($forcedownload) && $forcedownload)) {
+#        &Apache::lonnet::logthis("loading data");
+        # Get all the students current data
+        my $time_of_retrieval = time;
+        my @tmp = &Apache::lonnet::currentdump($courseid,$sdom,$sname);
+        if ((scalar(@tmp) > 0) && ($tmp[0] =~ /^error:/)) {
+            &Apache::lonnet::logthis('error getting data for '.
+                                     $sname.':'.$sdom.' in course '.$courseid.
+                                     ':'.$tmp[0]);
+            return ();
+        }
+        %student_data = @tmp;
+        #
+        # Store away the data
+        #
+        # The cache structure is colon deliminated.  
+        # $uname:$udom:time  => timestamp
+        # $uname:$udom:$symb => $parm1:$val1:$parm2:$val2 ...
+        #
+        # BEWARE: The colons are NOT escaped so can search with escaped 
+        #         keys instead of unescaping every key.
+        #
+        if (tie(%cache,'GDBM_File',$cachefilename,&GDBM_WRCREAT(),0640)) {
+#            &Apache::lonnet::logthis("writing data");
+            while (my ($current_symb,$param_hash) = each(%student_data)) {
+                my @Parameters = %{$param_hash};
+                my $value = join(':',map { &Apache::lonnet::escape($_); } 
+                                 @Parameters);
+                # Store away the values
+                $cache{$key.&Apache::lonnet::escape($symb)}=$value;
+            }
+            $cache{$key.'time'}=$time_of_retrieval;
+            untie(%cache);
+        }
+    } else {
+#        &Apache::lonnet::logthis('retrieving cached data ');
+        if (tie(%cache,'GDBM_File',$cachefilename,&GDBM_READER(),0640)) {
+            if (defined($symb)) {
+                my  $searchkey = $key.&Apache::lonnet::escape($symb);
+                if (exists($cache{$searchkey})) {
+                    $student_data{$symb} = &make_into_hash($cache{$searchkey});
+                }
+            } else {
+                my $searchkey = '^'.$key.'(.*)$';#'
+                while (my ($testkey,$params)=each(%cache)) {
+                    if ($testkey =~ /$searchkey/) { # \Q \E?  May be necc.
+                        $student_data{&Apache::lonnet::unescape($1)} = 
+                            &make_into_hash($params);
+                    }
+                }
+            }
+            untie(%cache);
+        }
     }
-    my %student_data = @tmp;
     if (! defined($symb)) {
+#        &Apache::lonnet::logthis("returning all data");
         return %student_data;
     } elsif (exists($student_data{$symb})) {
+#        &Apache::lonnet::logthis("returning data for symb=".$symb);
         return %{$student_data{$symb}};
     } else {
         return ();