--- rat/lonuserstate.pm	2000/08/22 15:26:28	1.4
+++ rat/lonuserstate.pm	2004/04/23 15:23:35	1.73
@@ -1,32 +1,102 @@
 # The LearningOnline Network with CAPA
 # Construct and maintain state and binary representation of course for user
 #
-# (Server for RAT Maps
+# $Id: lonuserstate.pm,v 1.73 2004/04/23 15:23:35 www Exp $
 #
-# (Edit Handler for RAT Maps
-# (TeX Content Handler
+# Copyright Michigan State University Board of Trustees
 #
-# 05/29/00,05/30 Gerd Kortemeyer)
-# 7/1 Gerd Kortemeyer)
-# 7/1,7/3,7/4,7/7,7/8,7/10 Gerd Kortemeyer)
+# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
 #
-# 7/15,7/17,7/18,8/1,8/2,8/4,8/5,8/21,8/22 Gerd Kortemeyer
+# LON-CAPA is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# LON-CAPA is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with LON-CAPA; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# /home/httpd/html/adm/gpl.txt
+#
+# http://www.lon-capa.org/
+#
+###
 
 package Apache::lonuserstate;
 
+# ------------------------------------------------- modules used by this module
 use strict;
 use Apache::Constants qw(:common :http);
 use Apache::File;
 use HTML::TokeParser;
 use Apache::lonnet();
+use Apache::loncommon();
 use GDBM_File;
+use Apache::lonmsg;
+use Safe;
+use Safe::Hole;
+use Opcode;
+use Apache::lonenc;
 
 # ---------------------------------------------------- Globals for this package
 
 my $pc;      # Package counter
 my %hash;    # The big tied hash
+my %parmhash;# The hash with the parameters
 my @cond;    # Array with all of the conditions
 my $errtext; # variable with all errors
+my $retfurl; # variable with the very first URL in the course
+my %randompick; # randomly picked resources
+my %randompickseed; # optional seed for randomly picking resources
+my %encurl; # URLs in this folder are supposed to be encrypted
+my %hiddenurl; # this URL (or complete folder) is supposed to be hidden
+
+# ----------------------------------- Remove version from URL and store in hash
+
+sub versiontrack {
+    my $uri=shift;
+    if ($uri=~/\.(\d+)\.\w+$/) {
+	my $version=$1;
+	$uri=~s/\.\d+\.(\w+)$/\.$1/;
+        unless ($hash{'version_'.$uri}) {
+	    $hash{'version_'.$uri}=$version;
+	}
+    }
+    return $uri;
+}
+
+# -------------------------------------------------------------- Put in version
+
+sub putinversion {
+    my $uri=shift;
+    if ($hash{'version_'.$uri}) {
+	my $version=$hash{'version_'.$uri};
+	if ($version eq 'mostrecent') { return $uri; }
+	if ($version eq &Apache::lonnet::getversion(
+			&Apache::lonnet::filelocation('',$uri))) 
+	             { return $uri; }
+	$uri=~s/\.(\w+)$/\.$version\.$1/;
+    }
+    return $uri;
+}
+
+# ----------------------------------------- Processing versions file for course
+
+sub processversionfile {
+    my %cenv=@_;
+    my %versions=&Apache::lonnet::dump('resourceversions',
+				       $cenv{'domain'},
+				       $cenv{'num'});
+    foreach (keys %versions) {
+	if ($_=~/^error\:/) { return; }
+	$hash{'version_'.$_}=$versions{$_};
+    }
+}
 
 # --------------------------------------------------------- Loads map from disk
 
@@ -39,39 +109,23 @@ sub loadmap {
     $hash{'map_pc_'.$uri}=$lpc;
     $hash{'map_id_'.$lpc}=$uri;
 
-    my $fn='/home/httpd/html'.$uri;
+# Determine and check filename
+    my $fn=&Apache::lonnet::filelocation('',&putinversion($uri));
 
-    unless (($fn=~/\.course$/) ||
-            ($fn=~/\.sequence$/) ||
+    my $ispage=($fn=~/\.page$/);
+
+    unless (($fn=~/\.sequence$/) ||
             ($fn=~/\.page$/)) { 
        $errtext.="Invalid map: $fn\n";
        return OK; 
     }
 
-    unless (-e $fn) {
-	my $returned=Apache::lonnet::repcopy($fn);
-        unless ($returned eq OK) {
-           $errtext.="Could not import: $fn - ";
-           if ($returned eq HTTP_SERVICE_UNAVAILABLE) {
-	      $errtext.="Server unavailable\n";
-           }
-           if ($returned eq HTTP_NOT_FOUND) {
-	      $errtext.="File not found\n";
-           }
-           if ($returned eq FORBIDDEN) {
-	      $errtext.="Access forbidden\n";
-           }
-           return OK;
-       }
-    }
+    my $instr=&Apache::lonnet::getfile($fn);
+
+    unless ($instr eq -1) {
+
+# Successfully got file, parse it
 
-    if (-e $fn) {
-        my @content;
-        {
-	    my $fh=Apache::File->new($fn);
-            @content=<$fh>;
-        }
-        my $instr=join('',@content);
         my $parser = HTML::TokeParser->new(\$instr);
         my $token;
 
@@ -90,16 +144,56 @@ sub loadmap {
 
                     $hash{'kind_'.$rid}='res';
                     $hash{'title_'.$rid}=$token->[2]->{'title'};
-                    my $turi=$token->[2]->{'src'};
-                    $hash{'src_'.$rid}=$turi;
-
-                    if (defined($hash{'ids_'.$turi})) {
-                        $hash{'ids_'.$turi}.=','.$rid;
+                    my $turi=&versiontrack($token->[2]->{'src'});
+                    if ($token->[2]->{'version'}) {
+			unless ($hash{'version_'.$turi}) {
+			    $hash{'version_'.$turi}=$1;
+			}
+		    }
+		    &Apache::lonnet::do_cache(\%Apache::lonnet::titlecache,
+		       &Apache::lonnet::encode_symb($uri,$token->[2]->{'id'},
+						    $turi),
+					      $token->[2]->{'title'},'title');
+                    unless ($ispage) {
+                        $turi=~/\.(\w+)$/;
+                        my $embstyle=&Apache::loncommon::fileembstyle($1);
+                        if ($token->[2]->{'external'} eq 'true') { # external
+                            $turi=~s/^http\:\/\//\/adm\/wrapper\/ext\//;
+                        } elsif ($turi=~/^\/*uploaded\//) { # uploaded
+			    if (($embstyle eq 'img') || ($embstyle eq 'emb')
+                             || ($embstyle eq 'ssi')) {
+                                unless ($turi =~/\.page$/) {
+                                    $turi='/adm/wrapper'.$turi;
+                                }
+                            } elsif ($turi!~/\.(sequence|page)$/) {
+				$turi='/adm/coursedocs/showdoc'.$turi;
+                            }
+                        } elsif ($turi=~/\S/) { # normal non-empty internal resource
+			    my $mapdir=$uri;
+			    $mapdir=~s/[^\/]+$//;
+			    $turi=&Apache::lonnet::hreflocation($mapdir,$turi);
+			    if (($embstyle eq 'img') || ($embstyle eq 'emb')) {
+				$turi='/adm/wrapper'.$turi;
+			    }
+                        }
+		    }
+# Store reverse lookup, remove query string
+		    my $idsuri=$turi;
+		    $idsuri=~s/\?.+$//;
+                    if (defined($hash{'ids_'.$idsuri})) {
+                        $hash{'ids_'.$idsuri}.=','.$rid;
                     } else {
-                        $hash{'ids_'.$turi}=''.$rid;
+                        $hash{'ids_'.$idsuri}=''.$rid;
                     }
+               
+                    if
+	        ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard)$/) {
+			$turi.='?register=1';
+		    }
 
-                    if ($token->[2]->{'src'}=~/\/\//) {
+                    $hash{'src_'.$rid}=$turi;
+
+                    if ($token->[2]->{'external'} eq 'true') {
                         $hash{'ext_'.$rid}='true:';
                     } else {
                         $hash{'ext_'.$rid}='false:';
@@ -116,8 +210,7 @@ sub loadmap {
                         $hash{'type_'.$rid}='normal';
                     }
 
-                    if (($turi=~/\.course$/) ||
-                        ($turi=~/\.sequence$/) ||
+                    if (($turi=~/\.sequence$/) ||
                         ($turi=~/\.page$/)) {
                         $hash{'is_map_'.$rid}=1;
                         &loadmap($turi);
@@ -165,6 +258,42 @@ sub loadmap {
                     } else {
                         $hash{'from_'.$goesto}=''.$linkid;
                     }
+                } elsif ($token->[1] eq 'param') {
+# ------------------------------------------------------------------- Parameter
+
+                    my $referid=$lpc.'.'.$token->[2]->{'to'};
+		    my $name=$token->[2]->{'name'};
+		    my $part;
+		    if ($name=~/^parameter_(.*)_/) {
+			$part=$1;
+		    } else {
+			$part=0;
+		    }
+		    $name=~s/^.*_([^_]*)$/$1/;
+                    my $newparam=
+			&Apache::lonnet::escape($token->[2]->{'type'}).':'.
+			&Apache::lonnet::escape($part.'.'.$name).'='.
+			&Apache::lonnet::escape($token->[2]->{'value'});
+                    if (defined($hash{'param_'.$referid})) {
+                        $hash{'param_'.$referid}.='&'.$newparam;
+                    } else {
+                        $hash{'param_'.$referid}=''.$newparam;
+                    }
+                    if ($token->[2]->{'name'} eq 'parameter_mapalias') {
+			$hash{'mapalias_'.$token->[2]->{'value'}}=$referid;
+                    }
+                    if ($token->[2]->{'name'} eq 'parameter_randompick') {
+			$randompick{$referid}=$token->[2]->{'value'};
+                    }
+                    if ($token->[2]->{'name'} eq 'parameter_randompickseed') {
+			$randompick{$referid}=$token->[2]->{'value'};
+                    }
+                    if ($token->[2]->{'name'} eq 'parameter_encrypturl') {
+			$encurl{$referid}=$token->[2]->{'value'};
+                    }
+                    if ($token->[2]->{'name'} eq 'parameter_hiddenresource') {
+			$hiddenurl{$referid}=$token->[2]->{'value'};
+                    }
                 } 
 
             }
@@ -179,16 +308,14 @@ sub loadmap {
 
 sub simplify {
    my $expression=shift;
-# "True and" is nothing 
-   $expression=~s/0\&//g;
 # (8)=8
    $expression=~s/\((\d+)\)/$1/g;
 # 8&8=8
-   $expression=~s/(\d+)\&\1/$1/g;
+   $expression=~s/(\D)(\d+)\&\2(\D)/$1$2$3/g;
 # 8|8=8
-   $expression=~s/(\d+)\|\1/$1/g;
+   $expression=~s/(\D)(\d+)\|\2(\D)/$1$2$3/g;
 # (5&3)&4=5&3&4
-   $expression=~s/\((\d+)\&(\d+)\)\&(\d+)/$1\&$2\&$3/g;
+   $expression=~s/\((\d+)((?:\&\d+)+)\)\&(\d+\D)/$1$2\&$3/g;
 # (((5&3)|(4&6)))=((5&3)|(4&6))
    $expression=~
        s/\((\(\(\d+(?:\&\d+)*\)(?:\|\(\d+(?:\&\d+)*\))+\))\)/$1/g;
@@ -205,6 +332,16 @@ sub traceroute {
     $sofar=simplify($sofar);
     unless ($beenhere=~/\&$rid\&/) {
        $beenhere.=$rid.'&';  
+       if (($retfurl eq '') && ($hash{'src_'.$rid})
+        && ($hash{'src_'.$rid}!~/\.sequence$/)) {
+           my ($mapid,$resid)=split(/\./,$rid);
+           $retfurl=$hash{'src_'.$rid}.
+           (($hash{'src_'.$rid}=~/\?/)?'&':'?').'symb='.
+           &Apache::lonnet::symbclean(
+                           &Apache::lonnet::declutter($hash{'map_id_'.$mapid}).
+                           '___'.$resid.'___'.
+                           &Apache::lonnet::declutter($hash{'src_'.$rid}));
+       }
        if (defined($hash{'conditions_'.$rid})) {
 	   $hash{'conditions_'.$rid}=simplify(
            '('.$hash{'conditions_'.$rid}.')|('.$sofar.')');
@@ -221,7 +358,7 @@ sub traceroute {
            }
        }
        if (defined($hash{'to_'.$rid})) {
-          map {
+          foreach (split(/\,/,$hash{'to_'.$rid})) {
 		my $further=$sofar;
                 if ($hash{'undercond_'.$_}) {
 		   if (defined($hash{'condid_'.$hash{'undercond_'.$_}})) {
@@ -233,87 +370,208 @@ sub traceroute {
                    }
                 }
                 &traceroute($further,$hash{'goesto_'.$_},$beenhere);
-          } split(/\,/,$hash{'to_'.$rid});
+          }
        }
     }
 }
 
-# ------------------------------------------ Cascading conditions, quick access
+# ------------------------------ Cascading conditions, quick access, parameters
 
 sub accinit {
     my ($uri,$short,$fn)=@_;
     my %acchash=();
     my %captured=();
     my $condcounter=0;
-    $acchash{'acc.cond.0'}='0';
-    map {
+    $acchash{'acc.cond.'.$short.'.0'}=0;
+    foreach (keys %hash) {
        if ($_=~/^conditions/) {
 	  my $expr=$hash{$_};
-          map {
+         foreach ($expr=~m/(\(\(\d+(?:\&\d+)+\)(?:\|\(\d+(?:\&\d+)+\))+\))/g) {
              my $sub=$_;
              my $orig=$_;
-             $sub=~/\(\((\d+(:?\&\d+)*)(?:\&\d+)+\)(?:\|\(\1(?:\&\d+)+\))+\)/;
+      $sub=~/\(\((\d+\&(:?\d+\&)*)(?:\d+\&*)+\)(?:\|\(\1(?:\d+\&*)+\))+\)/;
              my $factor=$1;
-             $sub=~s/$factor\&//g;
-             $sub=~s/^\(/\($factor\&\(/;
+             $sub=~s/$factor//g;
+             $sub=~s/^\(/\($factor\(/;
 	     $sub.=')';
              $sub=simplify($sub);
              $orig=~s/(\W)/\\$1/g;
-	     $expr=~s/$orig/$sub/;
-	  } ($expr=~m/(\(\(\d+(?:\&\d+)+\)(?:\|\(\d+(?:\&\d+)+\))+\))/g);
+ 	     $expr=~s/$orig/$sub/;
+	  }
           $hash{$_}=$expr;
           unless (defined($captured{$expr})) {
 	      $condcounter++;
               $captured{$expr}=$condcounter;
-              $acchash{'acc.cond.'.$condcounter}=$expr;
+              $acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;
           } 
-        }
-    } keys %hash;
-    map {
+       } elsif ($_=~/^param_(\d+)\.(\d+)/) {
+          my $prefix=&Apache::lonnet::declutter($hash{'map_id_'.$1}).
+      '___'.$2.'___'.&Apache::lonnet::declutter($hash{'src_'.$1.'.'.$2});
+          foreach (split(/\&/,$hash{$_})) {
+	     my ($typename,$value)=split(/\=/,$_);
+             my ($type,$name)=split(/\:/,$typename);
+             $parmhash{$prefix.'.'.&Apache::lonnet::unescape($name)}=
+                                   &Apache::lonnet::unescape($value);
+	     $parmhash{$prefix.'.'.&Apache::lonnet::unescape($name).'.type'}=
+                                   &Apache::lonnet::unescape($type);
+          }
+       }
+    }
+    foreach (keys %hash) {
 	if ($_=~/^ids/) {
-	    my $resid=$hash{$_};
+	  foreach (split(/\,/,$hash{$_})) {
+	    my $resid=$_;
             my $uri=$hash{'src_'.$resid};
+            $uri=~s/^\/adm\/wrapper//;
+            $uri=&Apache::lonnet::declutter($uri);
             my @uriparts=split(/\//,$uri);
             my $urifile=$uriparts[$#uriparts];
             $#uriparts--;
             my $uripath=join('/',@uriparts);
+           if ($uripath) {
+            my $uricond='0';
             if (defined($hash{'conditions_'.$resid})) {
- 		$urifile.=':'.$captured{$hash{'conditions_'.$resid}};
-            } else {
-                $urifile.=':0';
+ 		$uricond=$captured{$hash{'conditions_'.$resid}};
             }
-            if (defined($acchash{'acc.res.'.$uripath})) {
-		$acchash{'acc.res.'.$uripath}.=$urifile.'&';
+            if (defined($acchash{'acc.res.'.$short.'.'.$uripath})) {
+                if ($acchash{'acc.res.'.$short.'.'.$uripath}=~
+                   /(\&\Q$urifile\E\:[^\&]*)/) {
+		    my $replace=$1;
+                    my $regexp=$replace;
+                    $regexp=~s/\|/\\\|/g;
+                    $acchash{'acc.res.'.$short.'.'.$uripath}
+                     =~s/$regexp/$replace\|$uricond/;
+                } else {
+		   $acchash{'acc.res.'.$short.'.'.$uripath}.=
+                     $urifile.':'.$uricond.'&';
+	        }
             } else {
-                $acchash{'acc.res.'.$uripath}='&'.$urifile.'&';
+                $acchash{'acc.res.'.$short.'.'.$uripath}=
+                 '&'.$urifile.':'.$uricond.'&';
             }
-        }
-    } keys %hash;
+           } 
+         }
+      }
+    }
+    $acchash{'acc.res.'.$short.'.'}='&:0&';
+    my $courseuri=$uri;
+    $courseuri=~s/^\/res\///;
+    &Apache::lonnet::delenv('(acc\.|httpref\.)');
     &Apache::lonnet::appenv(%acchash,
-                            "request.course"    => $short,
-                            "request.course.fn" => $fn); 
+                            "request.course.id"  => $short,
+                            "request.course.fn"  => $fn,
+                            "request.course.uri" => $courseuri); 
 }
 
-# ---------------------------------------------------- Read map and all submaps
+# ---------------- Selectively delete from randompick maps and hidden url parms
 
-#
-# Call with uri of course map, short name for course, and filename for
-# binary structure
-#
+sub hiddenurls {
+    my $randomoutentry='';
+    foreach my $rid (keys %randompick) {
+        my $rndpick=$randompick{$rid};
+        my $mpc=$hash{'map_pc_'.$hash{'src_'.$rid}};
+# ------------------------------------------- put existing resources into array
+        my @currentrids=();
+        foreach (sort(keys(%hash))) {
+	    if ($_=~/^src_($mpc\.\d+)/) {
+		if ($hash{'src_'.$1}) { push @currentrids, $1; }
+            }
+        }
+	# rids are number.number and we want to numercially sort on 
+        # the second number
+	@currentrids=sort {
+	    my (undef,$aid)=split(/\./,$a);
+	    my (undef,$bid)=split(/\./,$b);
+	    $aid <=> $bid;
+	} @currentrids;
+        next if ($#currentrids<$rndpick);
+# -------------------------------- randomly eliminate the ones that should stay
+	my (undef,$id)=split(/\./,$rid);
+        if ($randompickseed{$rid}) { $id=$randompickseed{$rid}; }
+	my $rndseed=&Apache::lonnet::rndseed($id); # use id instead of symb
+	&Apache::lonnet::setup_random_from_rndseed($rndseed);
+	my @whichids=&Math::Random::random_permuted_index($#currentrids+1);
+        for (my $i=1;$i<=$rndpick;$i++) { $currentrids[$whichids[$i]]=''; }
+	#&Apache::lonnet::logthis("$id,$rndseed,".join(':',@whichids));
+# -------------------------------------------------------- delete the leftovers
+        for (my $k=0; $k<=$#currentrids; $k++) {
+            if ($currentrids[$k]) {
+		$hash{'randomout_'.$currentrids[$k]}=1;
+                my ($mapid,$resid)=split(/\./,$currentrids[$k]);
+                $randomoutentry.='&'.
+                 &Apache::lonnet::symbclean(
+		    &Apache::lonnet::declutter($hash{'map_id_'.$mapid}).
+                    '___'.$resid.'___'.
+		    &Apache::lonnet::declutter($hash{'src_'.$currentrids[$k]})
+                 ).'&';
+            }
+        }
+    }
+# ------------------------------ take care of explicitly hidden urls or folders
+    foreach my $rid (keys %hiddenurl) {
+	$hash{'randomout_'.$rid}=1;
+	my ($mapid,$resid)=split(/\./,$rid);
+	$randomoutentry.='&'.
+	    &Apache::lonnet::symbclean(
+		         &Apache::lonnet::declutter($hash{'map_id_'.$mapid}).
+				       '___'.$resid.'___'.
+		    &Apache::lonnet::declutter($hash{'src_'.$rid})
+				       ).'&';
+    }
+# --------------------------------------- append randomout entry to environment
+    if ($randomoutentry) {
+	&Apache::lonnet::appenv('acc.randomout' => $randomoutentry);
+    }
+}
+
+# ---------------------------------------------------- Read map and all submaps
 
 sub readmap {
-   my ($uri,$short,$fn)=@_;
+   my $short=shift;
+   $short=~s/^\///;
+   my %cenv=&Apache::lonnet::coursedescription($short);
+   my $fn=$cenv{'fn'};
+   my $uri;
+   $short=~s/\//\_/g;
+   unless ($uri=$cenv{'url'}) { 
+      &Apache::lonnet::logthis("<font color=blue>WARNING: ".
+                       "Could not load course $short.</font>"); 
+      return 'No course data available.';
+   }
    @cond=('true:normal');
-   if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT,0640)) {
+   unlink($fn.'.db');
+   unlink($fn.'_symb.db');
+   unlink($fn.'.state');
+   unlink($fn.'parms.db');
+   undef %randompick;
+   undef %hiddenurl;
+   undef %encurl;
+   $retfurl='';
+   if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) &&
+       (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640))) {
     %hash=();
+    %parmhash=();
     $errtext='';
     $pc=0;
+    &processversionfile(%cenv);
+    my $furi=&Apache::lonnet::clutter($uri);
+    $hash{'src_0.0'}=&versiontrack($furi);
+    $hash{'title_0.0'}=&Apache::lonnet::metadata($uri,'title');
+    $hash{'ids_'.$furi}='0.0';
+    $hash{'is_map_0.0'}=1;
     loadmap($uri);
     if (defined($hash{'map_start_'.$uri})) {
         &traceroute('0',$hash{'map_start_'.$uri},'&');
         &accinit($uri,$short,$fn);
+        &hiddenurls();
+    }
+# ------------------------------------------------------- Put versions into src
+    foreach (keys %hash) {
+	if ($_=~/^src\_/) {
+	    $hash{$_}=&putinversion($hash{$_});
+	}
     }
-    unless (untie(%hash)) {
+    unless ((untie(%hash)) && (untie(%parmhash))) {
       &Apache::lonnet::logthis("<font color=blue>WARNING: ".
                        "Could not untie coursemap $fn for $uri.</font>"); 
     }
@@ -322,23 +580,122 @@ sub readmap {
      if ($cfh=Apache::File->new(">$fn.state")) {
         print $cfh join("\n",@cond);
      } else {
-      &Apache::lonnet::logthis("<font color=blie>WARNING: ".
+      &Apache::lonnet::logthis("<font color=blue>WARNING: ".
                        "Could not write statemap $fn for $uri.</font>"); 
      }
     }  
    } else {
-      &Apache::lonnet::logthis("<font color=blie>WARNING: ".
+      &Apache::lonnet::logthis("<font color=blue>WARNING: ".
                        "Could not tie coursemap $fn for $uri.</font>"); 
    }
-   return $errtext;
+   &Apache::lonmsg::author_res_msg($ENV{'request.course.uri'},$errtext);
+# ------------------------------------------------- Check for critical messages
+
+    my @what=&Apache::lonnet::dump('critical',$ENV{'user.domain'},
+                                              $ENV{'user.name'});
+    if ($what[0]) {
+	if (($what[0] ne 'con_lost') && ($what[0]!~/^error\:/)) {
+	    $retfurl='/adm/email?critical=display';
+        }
+    }
+   return ($retfurl,$errtext);
+}
+
+# ------------------------------------------------------- Evaluate state string
+
+sub evalstate {
+
+    my $fn=$ENV{'request.course.fn'}.'.state';
+    my $state='2';
+    if (-e $fn) {
+       my @conditions=();
+       {
+        my $fh=Apache::File->new($fn);
+        @conditions=<$fh>;
+       }  
+       my $safeeval = new Safe;
+       my $safehole = new Safe::Hole;
+       $safeeval->permit("entereval");
+       $safeeval->permit(":base_math");
+       $safeeval->deny(":base_io");
+       $safehole->wrap(\&Apache::lonnet::EXT,$safeeval,'&EXT');
+       foreach (@conditions) {
+	   my $line=$_;
+           chomp($line);
+	   my ($condition,$weight)=split(/\:/,$_);
+           if ($safeeval->reval($condition)) {
+	       if ($weight eq 'force') {
+		   $state.='3';
+               } else {
+                   $state.='2';
+               }
+           } else {
+               if ($weight eq 'stop') {
+		   $state.='0';
+               } else {
+                   $state.='1';
+               }
+           }
+       }
+    }
+    &Apache::lonnet::appenv('user.state.'.$ENV{'request.course.id'} => $state);
+    return $state;
 }
- 
+
 1;
 __END__
 
+=head1 NAME
+
+Apache::lonuserstate - Construct and maintain state and binary representation
+of course for user
+
+=head1 SYNOPSIS
+
+Invoked by lonroles.pm.
+
+&Apache::lonuserstate::readmap($cdom.'/'.$cnum);
+
+=head1 INTRODUCTION
+
+This module constructs and maintains state and binary representation
+of course for user.
+
+This is part of the LearningOnline Network with CAPA project
+described at http://www.lon-capa.org.
+
+=head1 HANDLER SUBROUTINE
+
+There is no handler subroutine.
+
+=head1 OTHER SUBROUTINES
+
+=over 4
+
+=item *
+
+loadmap() : Loads map from disk
+
+=item *
+
+simplify() : Simplify expression
+
+=item *
+
+traceroute() : Build condition hash
+
+=item *
+
+accinit() : Cascading conditions, quick access, parameters
 
+=item *
 
+readmap() : Read map and all submaps
 
+=item *
 
+evalstate() : Evaluate state string
 
+=back
 
+=cut