--- rat/lonuserstate.pm	2005/07/14 21:30:24	1.94
+++ rat/lonuserstate.pm	2011/10/06 23:30:06	1.137.2.1
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Construct and maintain state and binary representation of course for user
 #
-# $Id: lonuserstate.pm,v 1.94 2005/07/14 21:30:24 albertel Exp $
+# $Id: lonuserstate.pm,v 1.137.2.1 2011/10/06 23:30:06 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,9 +31,9 @@ package Apache::lonuserstate;
 
 # ------------------------------------------------- modules used by this module
 use strict;
-use Apache::Constants qw(:common :http);
 use HTML::TokeParser;
 use Apache::lonnet;
+use Apache::lonlocal;
 use Apache::loncommon();
 use GDBM_File;
 use Apache::lonmsg;
@@ -41,6 +41,9 @@ use Safe;
 use Safe::Hole;
 use Opcode;
 use Apache::lonenc;
+use Fcntl qw(:flock);
+use LONCAPA;
+ 
 
 # ---------------------------------------------------- Globals for this package
 
@@ -49,14 +52,22 @@ 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 $retfrid; # variable with the very first RID in the course
+my $retfurl; # first URL
 my %randompick; # randomly picked resources
 my %randompickseed; # optional seed for randomly picking resources
+my %randomorder; # maps to order contents randomly
 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 versionerror {
+    my ($uri,$usedversion,$unusedversion)=@_;
+    return '<br />'.&mt('Version discrepancy: resource [_1] included in both version [_2] and version [_3]. Using version [_2].',
+                    $uri,$usedversion,$unusedversion).'<br />';
+}
+
 sub versiontrack {
     my $uri=shift;
     if ($uri=~/\.(\d+)\.\w+$/) {
@@ -64,7 +75,9 @@ sub versiontrack {
 	$uri=~s/\.\d+\.(\w+)$/\.$1/;
         unless ($hash{'version_'.$uri}) {
 	    $hash{'version_'.$uri}=$version;
-	}
+	} elsif ($version!=$hash{'version_'.$uri}) {
+            $errtext.=&versionerror($uri,$hash{'version_'.$uri},$version);
+        }
     }
     return $uri;
 }
@@ -93,22 +106,35 @@ sub processversionfile {
     my %versions=&Apache::lonnet::dump('resourceversions',
 				       $cenv{'domain'},
 				       $cenv{'num'});
-    foreach (keys %versions) {
-	if ($_=~/^error\:/) { return; }
-	$hash{'version_'.$_}=$versions{$_};
+    foreach my $ver (keys(%versions)) {
+	if ($ver=~/^error\:/) { return; }
+	$hash{'version_'.$ver}=$versions{$ver};
     }
 }
 
 # --------------------------------------------------------- Loads map from disk
 
 sub loadmap { 
-    my $uri=shift;
-    if ($hash{'map_pc_'.$uri}) { return OK; }
-
+    my ($uri,$parent_rid)=@_;
+    if ($hash{'map_pc_'.$uri}) { 
+	$errtext.='<p class="LC_error">'.
+	    &mt('Multiple use of sequence/page [_1]! The course will not function properly.','<tt>'.$uri.'</tt>').
+	    '</p>';
+	return; 
+    }
     $pc++;
     my $lpc=$pc;
     $hash{'map_pc_'.$uri}=$lpc;
     $hash{'map_id_'.$lpc}=$uri;
+    if ($parent_rid =~ /^(\d+)\.\d+$/) {
+        my $parent_pc = $1;
+        if (defined($hash{'map_hierarchy_'.$parent_pc})) {
+            $hash{'map_hierarchy_'.$lpc}=$hash{'map_hierarchy_'.$parent_pc}.','.
+                                         $parent_pc;
+        } else {
+            $hash{'map_hierarchy_'.$lpc}=$parent_pc;
+        }
+    }
 
 # Determine and check filename
     my $fn=&Apache::lonnet::filelocation('',&putinversion($uri));
@@ -117,196 +143,286 @@ sub loadmap {
 
     unless (($fn=~/\.sequence$/) ||
             ($fn=~/\.page$/)) { 
-	$errtext.="Invalid map: $fn\n";
-	return OK; 
+	$errtext.=&mt("<br />Invalid map: <tt>[_1]</tt>",$fn);
+	return; 
     }
 
     my $instr=&Apache::lonnet::getfile($fn);
 
-    unless ($instr eq -1) {
+    if ($instr eq -1) {
+        $errtext.=&mt('<br />Map not loaded: The file <tt>[_1]</tt> does not exist.',$fn);
+	return;
+    }
 
 # Successfully got file, parse it
 
-        my $parser = HTML::TokeParser->new(\$instr);
-	#$parser->attr_encoded(1);
-        my $token;
+    my $parser = HTML::TokeParser->new(\$instr);
+    $parser->attr_encoded(1);
+    # first get all parameters
+    while (my $token = $parser->get_token) {
+	next if ($token->[0] ne 'S');
+	if ($token->[1] eq 'param') {
+	    &parse_param($token,$lpc);
+	} 
+    }
+    #reset parser
+    $parser = HTML::TokeParser->new(\$instr);
+    $parser->attr_encoded(1);
 
-        my $linkpc=0;
+    my $linkpc=0;
 
-        $fn=~/\.(\w+)$/;
+    $fn=~/\.(\w+)$/;
 
-        $hash{'map_type_'.$lpc}=$1;
+    $hash{'map_type_'.$lpc}=$1;
 
-        while ($token = $parser->get_token) {
-	    if ($token->[0] eq 'S') {
-                if ($token->[1] eq 'resource') {
-# -------------------------------------------------------------------- Resource
-                    if ($token->[2]->{'type'} eq 'zombie') { next; }
-                    my $rid=$lpc.'.'.$token->[2]->{'id'};
+    my $randomize = ($randomorder{$parent_rid} =~ /^yes$/i);
 
-                    $hash{'kind_'.$rid}='res';
-                    $hash{'title_'.$rid}=$token->[2]->{'title'};
-                    my $turi=&versiontrack($token->[2]->{'src'});
-                    if ($token->[2]->{'version'}) {
-			unless ($hash{'version_'.$turi}) {
-			    $hash{'version_'.$turi}=$1;
-			}
-		    }
-		    my $title=$token->[2]->{'title'};
-		    $title=~s/\&colon\;/\:/gs;
-#		    my $symb=&Apache::lonnet::encode_symb($uri,
-#							  $token->[2]->{'id'},
-#							  $turi);
-#		    &Apache::lonnet::do_cache_new('title',$symb,$title);
-                    unless ($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')) {
-                                $turi='/adm/wrapper'.$turi;
-			    } elsif ($embstyle eq 'ssi') {
-				#do nothing with these
-			    } elsif ($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 {
-                        $hash{'ids_'.$idsuri}=''.$rid;
-                    }
-               
-                    if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard)$/) {
-			$turi.='?register=1';
-		    }
+    my @map_ids;
+    while (my $token = $parser->get_token) {
+	next if ($token->[0] ne 'S');
+	if ($token->[1] eq 'resource') {
+	    push(@map_ids,&parse_resource($token,$lpc,$ispage,$uri));
+	} elsif ($token->[1] eq 'link' && !$randomize) {
+# ----------------------------------------------------------------------- Links
+	    &make_link(++$linkpc,$lpc,$token->[2]->{'to'},
+		       $token->[2]->{'from'},
+		       $token->[2]->{'condition'});
+	} elsif ($token->[1] eq 'condition' && !$randomize) {
+	    &parse_condition($token,$lpc);
+	}
+    }
 
-                    $hash{'src_'.$rid}=$turi;
+    if ($randomize) {
+	if (!$env{'request.role.adv'}) {
+	    my $seed;
+	    if (defined($randompickseed{$parent_rid})) {
+		$seed = $randompickseed{$parent_rid};
+	    } else {
+		my ($mapid,$resid)=split(/\./,$parent_rid);
+		my $symb=
+		    &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
+						 $resid,$hash{'src_'.$parent_rid});
+		
+		$seed = $symb;
+	    }
+	
+	    my $rndseed=&Apache::lonnet::rndseed($seed);
+	    &Apache::lonnet::setup_random_from_rndseed($rndseed);
+	    @map_ids=&Math::Random::random_permutation(@map_ids);
+	}
+	my $from = shift(@map_ids);
+	my $from_rid = $lpc.'.'.$from;
+	$hash{'map_start_'.$uri} = $from_rid;
+	$hash{'type_'.$from_rid}='start';
+
+	while (my $to = shift(@map_ids)) {
+	    &make_link(++$linkpc,$lpc,$to,$from);
+	    my $to_rid =  $lpc.'.'.$to;
+	    $hash{'type_'.$to_rid}='normal';
+	    $from = $to;
+	    $from_rid = $to_rid;
+	}
 
-                    if ($token->[2]->{'external'} eq 'true') {
-                        $hash{'ext_'.$rid}='true:';
-                    } else {
-                        $hash{'ext_'.$rid}='false:';
-                    }
-                    if ($token->[2]->{'type'}) {
-			$hash{'type_'.$rid}=$token->[2]->{'type'};
-                        if ($token->[2]->{'type'} eq 'start') {
-			    $hash{'map_start_'.$uri}="$rid";
-                        }
-                        if ($token->[2]->{'type'} eq 'finish') {
-			    $hash{'map_finish_'.$uri}="$rid";
-                        }
-                    }  else {
-                        $hash{'type_'.$rid}='normal';
-                    }
+	$hash{'map_finish_'.$uri}= $from_rid;
+	$hash{'type_'.$from_rid}='finish';
+    }
 
-                    if (($turi=~/\.sequence$/) ||
-                        ($turi=~/\.page$/)) {
-                        $hash{'is_map_'.$rid}=1;
-                        &loadmap($turi);
-                    } 
-                    
-                } elsif ($token->[1] eq 'condition') {
-# ------------------------------------------------------------------- Condition
+    $parser = HTML::TokeParser->new(\$instr);
+    $parser->attr_encoded(1);
+    # last parse out the mapalias params so as to ignore anything
+    # refering to non-existant resources
+    while (my $token = $parser->get_token) {
+	next if ($token->[0] ne 'S');
+	if ($token->[1] eq 'param') {
+	    &parse_mapalias_param($token,$lpc);
+	} 
+    }
+}
 
-                    my $rid=$lpc.'.'.$token->[2]->{'id'};
 
-                    $hash{'kind_'.$rid}='cond';
-                    $cond[$#cond+1]=$token->[2]->{'value'};
-                    $hash{'condid_'.$rid}=$#cond;
-                    if ($token->[2]->{'type'}) {
-                        $cond[$#cond].=':'.$token->[2]->{'type'};
-                    }  else {
-                        $cond[$#cond].=':normal';
-                    }
+# -------------------------------------------------------------------- Resource
+sub parse_resource {
+    my ($token,$lpc,$ispage,$uri) = @_;
+    if ($token->[2]->{'type'} eq 'zombie') { next; }
+    my $rid=$lpc.'.'.$token->[2]->{'id'};
+	    
+    $hash{'kind_'.$rid}='res';
+    $hash{'title_'.$rid}=$token->[2]->{'title'};
+    my $turi=&versiontrack($token->[2]->{'src'});
+    if ($token->[2]->{'version'}) {
+	unless ($hash{'version_'.$turi}) {
+	    $hash{'version_'.$turi}=$1;
+	}
+    }
+    my $title=$token->[2]->{'title'};
+    $title=~s/\&colon\;/\:/gs;
+#   my $symb=&Apache::lonnet::encode_symb($uri,
+#					  $token->[2]->{'id'},
+#					  $turi);
+#   &Apache::lonnet::do_cache_new('title',$symb,$title);
+    unless ($ispage) {
+	$turi=~/\.(\w+)$/;
+	my $embstyle=&Apache::loncommon::fileembstyle($1);
+	if ($token->[2]->{'external'} eq 'true') { # external
+	    $turi=~s/^https?\:\/\//\/adm\/wrapper\/ext\//;
+	} elsif ($turi=~/^\/*uploaded\//) { # uploaded
+	    if (($embstyle eq 'img') 
+		|| ($embstyle eq 'emb')
+		|| ($embstyle eq 'wrp')) {
+		$turi='/adm/wrapper'.$turi;
+	    } elsif ($embstyle eq 'ssi') {
+		#do nothing with these
+	    } elsif ($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') 
+		|| ($embstyle eq 'emb')
+		|| ($embstyle eq 'wrp')) {
+		$turi='/adm/wrapper'.$turi;
+	    }
+	}
+    }
+# Store reverse lookup, remove query string
+    my $idsuri=$turi;
+    $idsuri=~s/\?.+$//;
+    if (defined($hash{'ids_'.$idsuri})) {
+	$hash{'ids_'.$idsuri}.=','.$rid;
+    } else {
+	$hash{'ids_'.$idsuri}=''.$rid;
+    }
+    
+    if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard|viewclasslist)$/) {
+	$turi.='?register=1';
+    }
+    
+    $hash{'src_'.$rid}=$turi;
+    
+    if ($token->[2]->{'external'} eq 'true') {
+	$hash{'ext_'.$rid}='true:';
+    } else {
+	$hash{'ext_'.$rid}='false:';
+    }
+    if ($token->[2]->{'type'}) {
+	$hash{'type_'.$rid}=$token->[2]->{'type'};
+	if ($token->[2]->{'type'} eq 'start') {
+	    $hash{'map_start_'.$uri}="$rid";
+	}
+	if ($token->[2]->{'type'} eq 'finish') {
+	    $hash{'map_finish_'.$uri}="$rid";
+	}
+    }  else {
+	$hash{'type_'.$rid}='normal';
+    }
+    
+    if (($turi=~/\.sequence$/) ||
+	($turi=~/\.page$/)) {
+	$hash{'is_map_'.$rid}=1;
+	&loadmap($turi,$rid);
+    } 
+    return $token->[2]->{'id'};
+}
 
-                } elsif ($token->[1] eq 'link') {
-# ----------------------------------------------------------------------- Links
+sub make_link {
+    my ($linkpc,$lpc,$to,$from,$condition) = @_;
+    
+    my $linkid=$lpc.'.'.$linkpc;
+    my $goesto=$lpc.'.'.$to;
+    my $comesfrom=$lpc.'.'.$from;
+    my $undercond=0;
 
-                    $linkpc++;
-                    my $linkid=$lpc.'.'.$linkpc;
+    if ($condition) {
+	$undercond=$lpc.'.'.$condition;
+    }
 
-                    my $goesto=$lpc.'.'.$token->[2]->{'to'};
-                    my $comesfrom=$lpc.'.'.$token->[2]->{'from'};
-                    my $undercond=0;
+    $hash{'goesto_'.$linkid}=$goesto;
+    $hash{'comesfrom_'.$linkid}=$comesfrom;
+    $hash{'undercond_'.$linkid}=$undercond;
 
-                    if ($token->[2]->{'condition'}) {
-			$undercond=$lpc.'.'.$token->[2]->{'condition'};
-                    }
+    if (defined($hash{'to_'.$comesfrom})) {
+	$hash{'to_'.$comesfrom}.=','.$linkid;
+    } else {
+	$hash{'to_'.$comesfrom}=''.$linkid;
+    }
+    if (defined($hash{'from_'.$goesto})) {
+	$hash{'from_'.$goesto}.=','.$linkid;
+    } else {
+	$hash{'from_'.$goesto}=''.$linkid;
+    }
+}
 
-                    $hash{'goesto_'.$linkid}=$goesto;
-                    $hash{'comesfrom_'.$linkid}=$comesfrom;
-                    $hash{'undercond_'.$linkid}=$undercond;
-
-                    if (defined($hash{'to_'.$comesfrom})) {
-                        $hash{'to_'.$comesfrom}.=','.$linkid;
-                    } else {
-                        $hash{'to_'.$comesfrom}=''.$linkid;
-                    }
-                    if (defined($hash{'from_'.$goesto})) {
-                        $hash{'from_'.$goesto}.=','.$linkid;
-                    } else {
-                        $hash{'from_'.$goesto}=''.$linkid;
-                    }
-                } elsif ($token->[1] eq 'param') {
-# ------------------------------------------------------------------- Parameter
+# ------------------------------------------------------------------- Condition
+sub parse_condition {
+    my ($token,$lpc) = @_;
+    my $rid=$lpc.'.'.$token->[2]->{'id'};
+    
+    $hash{'kind_'.$rid}='cond';
+
+    my $condition = $token->[2]->{'value'};
+    $condition =~ s/[\n\r]+/ /gs;
+    push(@cond, $condition);
+    $hash{'condid_'.$rid}=$#cond;
+    if ($token->[2]->{'type'}) {
+	$cond[$#cond].=':'.$token->[2]->{'type'};
+    }  else {
+	$cond[$#cond].=':normal';
+    }
+}
 
-                    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'}=~/^parameter_(0_)*mapalias$/) {
-			$hash{'mapalias_'.$token->[2]->{'value'}}=$referid;
-                    }
-                    if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) {
-			$randompick{$referid}=$token->[2]->{'value'};
-                    }
-                    if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) {
-			$randompick{$referid}=$token->[2]->{'value'};
-                    }
-                    if ($token->[2]->{'name'}=~/^parameter_(0_)*encrypturl$/) {
-			if ($token->[2]->{'value'}=~/^yes$/i) {
-			    $encurl{$referid}=1;
-			}
-                    }
-                    if ($token->[2]->{'name'}=~/^parameter_(0_)*hiddenresource$/) {
-			if ($token->[2]->{'value'}=~/^yes$/i) {
-			    $hiddenurl{$referid}=1;
-			}
-                    }
-                } 
-		
-            }
-        }
+# ------------------------------------------------------------------- Parameter
 
+sub parse_param {
+    my ($token,$lpc) = @_;
+    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 $newparam=
+	&escape($token->[2]->{'type'}).':'.
+	&escape($part.'.'.$name).'='.
+	&escape($token->[2]->{'value'});
+    if (defined($hash{'param_'.$referid})) {
+	$hash{'param_'.$referid}.='&'.$newparam;
     } else {
-        $errtext.='Map not loaded: The file ('.$fn.') does not exist. ';
+	$hash{'param_'.$referid}=''.$newparam;
+    }
+    if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) {
+	$randompick{$referid}=$token->[2]->{'value'};
+    }
+    if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) {
+	$randompickseed{$referid}=$token->[2]->{'value'};
+    }
+    if ($token->[2]->{'name'}=~/^parameter_(0_)*randomorder$/) {
+	$randomorder{$referid}=$token->[2]->{'value'};
+    }
+    if ($token->[2]->{'name'}=~/^parameter_(0_)*encrypturl$/) {
+	if ($token->[2]->{'value'}=~/^yes$/i) {
+	    $encurl{$referid}=1;
+	}
+    }
+    if ($token->[2]->{'name'}=~/^parameter_(0_)*hiddenresource$/) {
+	if ($token->[2]->{'value'}=~/^yes$/i) {
+	    $hiddenurl{$referid}=1;
+	}
+    }
+}
+
+sub parse_mapalias_param {
+    my ($token,$lpc) = @_;
+    my $referid=$lpc.'.'.$token->[2]->{'to'};
+    return if (!exists($hash{'src_'.$referid}));
+
+    if ($token->[2]->{'name'}=~/^parameter_(0_)*mapalias$/) {
+	&count_mapalias($token->[2]->{'value'},$referid);
+	$hash{'mapalias_'.$token->[2]->{'value'}}=$referid;
     }
 }
 
@@ -314,20 +430,22 @@ sub loadmap {
 
 sub simplify {
     my $expression=shift;
+# (0&1) = 1
+    $expression=~s/\(0\&([_\.\d]+)\)/$1/g;
 # (8)=8
-    $expression=~s/\((\d+)\)/$1/g;
+    $expression=~s/\(([_\.\d]+)\)/$1/g;
 # 8&8=8
-    $expression=~s/(\D)(\d+)\&\2(\D)/$1$2$3/g;
+    $expression=~s/([^_\.\d])([_\.\d]+)\&\2([^_\.\d])/$1$2$3/g;
 # 8|8=8
-    $expression=~s/(\D)(\d+)\|\2(\D)/$1$2$3/g;
+    $expression=~s/([^_\.\d])([_\.\d]+)(?:\|\2)+([^_\.\d])/$1$2$3/g;
 # (5&3)&4=5&3&4
-    $expression=~s/\((\d+)((?:\&\d+)+)\)\&(\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;
+	s/\((\(\([_\.\d]+(?:\&[_\.\d]+)*\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+\))\)/$1/g;
 # ((5&3)|(4&6))|(1&2)=(5&3)|(4&6)|(1&2)
     $expression=~
-	s/\((\(\d+(?:\&\d+)*\))((?:\|\(\d+(?:\&\d+)*\))+)\)\|(\(\d+(?:\&\d+)*\))/\($1$2\|$3\)/g;
+	s/\((\([_\.\d]+(?:\&[_\.\d]+)*\))((?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+)\)\|(\([_\.\d]+(?:\&[_\.\d]+)*\))/\($1$2\|$3\)/g;
     return $expression;
 }
 
@@ -336,7 +454,7 @@ sub simplify {
 sub traceroute {
     my ($sofar,$rid,$beenhere,$encflag,$hdnflag)=@_;
     my $newsofar=$sofar=simplify($sofar);
-    unless ($beenhere=~/\&$rid\&/) {
+    unless ($beenhere=~/\&\Q$rid\E\&/) {
 	$beenhere.=$rid.'&';  
 	my ($mapid,$resid)=split(/\./,$rid);
 	my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,$hash{'src_'.$rid});
@@ -351,10 +469,9 @@ sub traceroute {
 
 	my $encrypt=&Apache::lonnet::EXT('resource.0.encrypturl',$symb);
 	if ($encflag || lc($encrypt) eq 'yes') { $encurl{$rid}=1; }
-	if (($retfurl eq '') && ($hash{'src_'.$rid})
+	if (($retfrid eq '') && ($hash{'src_'.$rid})
 	    && ($hash{'src_'.$rid}!~/\.sequence$/)) {
-	    $retfurl=$hash{'src_'.$rid}.(($hash{'src_'.$rid}=~/\?/)?'&':'?').
-		'symb='.$symb;
+	    $retfrid=$rid;
 	}
 	if (defined($hash{'conditions_'.$rid})) {
 	    $hash{'conditions_'.$rid}=simplify(
@@ -362,29 +479,33 @@ sub traceroute {
 	} else {
 	    $hash{'conditions_'.$rid}=$sofar;
 	}
-	$newsofar=$hash{'conditions_'.$rid};
+
+	# if the expression is just the 0th condition keep it
+	# otherwise leave a pointer to this condition expression
+	$newsofar = ($sofar eq '0') ? $sofar : '_'.$rid;
+
 	if (defined($hash{'is_map_'.$rid})) {
 	    if (defined($hash{'map_start_'.$hash{'src_'.$rid}})) {
 		$sofar=$newsofar=
 		    &traceroute($sofar,
-				$hash{'map_start_'.$hash{'src_'.$rid}},'&',
+				$hash{'map_start_'.$hash{'src_'.$rid}},
+				$beenhere,
 				$encflag || $encurl{$rid},
 				$hdnflag || $hiddenurl{$rid});
 	    }
 	}
 	if (defined($hash{'to_'.$rid})) {
-	    foreach (split(/\,/,$hash{'to_'.$rid})) {
+	    foreach my $id (split(/\,/,$hash{'to_'.$rid})) {
 		my $further=$sofar;
-                if ($hash{'undercond_'.$_}) {
-		    if (defined($hash{'condid_'.$hash{'undercond_'.$_}})) {
-			$further=simplify('('.$further.')&('.
-					  $hash{'condid_'.$hash{'undercond_'.$_}}.')');
+                if ($hash{'undercond_'.$id}) {
+		    if (defined($hash{'condid_'.$hash{'undercond_'.$id}})) {
+			$further=simplify('('.'_'.$rid.')&('.
+					  $hash{'condid_'.$hash{'undercond_'.$id}}.')');
 		    } else {
-			$errtext.='Undefined condition ID: '
-			    .$hash{'undercond_'.$_}.'. ';
+			$errtext.=&mt('<br />Undefined condition ID: [_1]',$hash{'undercond_'.$id});
 		    }
                 }
-                $newsofar=&traceroute($further,$hash{'goesto_'.$_},$beenhere,
+                $newsofar=&traceroute($further,$hash{'goesto_'.$id},$beenhere,
 				      $encflag,$hdnflag);
 	    }
 	}
@@ -400,51 +521,47 @@ sub accinit {
     my %captured=();
     my $condcounter=0;
     $acchash{'acc.cond.'.$short.'.0'}=0;
-    foreach (keys %hash) {
-	if ($_=~/^conditions/) {
-	    my $expr=$hash{$_};
-	    foreach ($expr=~m/(\(\(\d+(?:\&\d+)+\)(?:\|\(\d+(?:\&\d+)+\))+\))/g) {
-		my $sub=$_;
-		my $orig=$_;
-		$sub=~/\(\((\d+\&(:?\d+\&)*)(?:\d+\&*)+\)(?:\|\(\1(?:\d+\&*)+\))+\)/;
-		my $factor=$1;
-		$sub=~s/$factor//g;
+    foreach my $key (keys(%hash)) {
+	if ($key=~/^conditions/) {
+	    my $expr=$hash{$key};
+	    # try to find and factor out common sub-expressions
+	    foreach my $sub ($expr=~m/(\(\([_\.\d]+(?:\&[_\.\d]+)+\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)+\))+\))/g) {
+		my $orig=$sub;
+
+		my ($factor) = ($sub=~/\(\(([_\.\d]+\&(:?[_\.\d]+\&)*)(?:[_\.\d]+\&*)+\)(?:\|\(\1(?:[_\.\d]+\&*)+\))+\)/);
+		next if (!defined($factor));
+
+		$sub=~s/\Q$factor\E//g;
 		$sub=~s/^\(/\($factor\(/;
 		$sub.=')';
 		$sub=simplify($sub);
-		$orig=~s/(\W)/\\$1/g;
-		$expr=~s/$orig/$sub/;
+		$expr=~s/\Q$orig\E/$sub/;
 	    }
-	    $hash{$_}=$expr;
+	    $hash{$key}=$expr;
 	    unless (defined($captured{$expr})) {
 		$condcounter++;
 		$captured{$expr}=$condcounter;
 		$acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;
 	    } 
-	} elsif ($_=~/^param_(\d+)\.(\d+)/) {
+	} elsif ($key=~/^param_(\d+)\.(\d+)/) {
 	    my $prefix=&Apache::lonnet::encode_symb($hash{'map_id_'.$1},$2,
 						    $hash{'src_'.$1.'.'.$2});
-	    foreach (split(/\&/,$hash{$_})) {
-		my ($typename,$value)=split(/\=/,$_);
+	    foreach my $param (split(/\&/,$hash{$key})) {
+		my ($typename,$value)=split(/\=/,$param);
 		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);
+		$parmhash{$prefix.'.'.&unescape($name)}=
+		    &unescape($value);
+		$parmhash{$prefix.'.'.&unescape($name).'.type'}=
+		    &unescape($type);
 	    }
 	}
     }
-    foreach (keys %hash) {
-	if ($_=~/^ids/) {
-	    foreach (split(/\,/,$hash{$_})) {
-		my $resid=$_;
+    foreach my $key (keys(%hash)) {
+	if ($key=~/^ids/) {
+	    foreach my $resid (split(/\,/,$hash{$key})) {
 		my $uri=$hash{'src_'.$resid};
-		$uri=~s/^\/adm\/wrapper//;
-		$uri=&Apache::lonnet::declutter($uri);
-		my @uriparts=split(/\//,$uri);
-		my $urifile=$uriparts[$#uriparts];
-		$#uriparts--;
-		my $uripath=join('/',@uriparts);
+		my ($uripath,$urifile) =
+		    &Apache::lonnet::split_uri_for_cond($uri);
 		if ($uripath) {
 		    my $uricond='0';
 		    if (defined($hash{'conditions_'.$resid})) {
@@ -456,8 +573,8 @@ sub accinit {
 			    my $replace=$1;
 			    my $regexp=$replace;
 			    #$regexp=~s/\|/\\\|/g;
-			    $acchash{'acc.res.'.$short.'.'.$uripath}
-			    =~s/\Q$regexp\E/$replace\|$uricond/;
+			    $acchash{'acc.res.'.$short.'.'.$uripath} =~
+				s/\Q$regexp\E/$replace\|$uricond/;
 			} else {
 			    $acchash{'acc.res.'.$short.'.'.$uripath}.=
 				$urifile.':'.$uricond.'&';
@@ -473,8 +590,9 @@ sub accinit {
     $acchash{'acc.res.'.$short.'.'}='&:0&';
     my $courseuri=$uri;
     $courseuri=~s/^\/res\///;
-    &Apache::lonnet::delenv('(acc\.|httpref\.)');
-    &Apache::lonnet::appenv(%acchash);
+    my $regexp = 1;
+    &Apache::lonnet::delenv('(acc\.|httpref\.)',$regexp);
+    &Apache::lonnet::appenv(\%acchash);
 }
 
 # ---------------- Selectively delete from randompick maps and hidden url parms
@@ -486,8 +604,8 @@ sub hiddenurls {
         my $mpc=$hash{'map_pc_'.$hash{'src_'.$rid}};
 # ------------------------------------------- put existing resources into array
         my @currentrids=();
-        foreach (sort(keys(%hash))) {
-	    if ($_=~/^src_($mpc\.\d+)/) {
+        foreach my $key (sort(keys(%hash))) {
+	    if ($key=~/^src_($mpc\.\d+)/) {
 		if ($hash{'src_'.$1}) { push @currentrids, $1; }
             }
         }
@@ -530,7 +648,7 @@ sub hiddenurls {
     }
 # --------------------------------------- append randomout entry to environment
     if ($randomoutentry) {
-	&Apache::lonnet::appenv('acc.randomout' => $randomoutentry);
+	&Apache::lonnet::appenv({'acc.randomout' => $randomoutentry});
     }
 }
 
@@ -539,103 +657,172 @@ sub hiddenurls {
 sub readmap {
     my $short=shift;
     $short=~s/^\///;
-    my %cenv=&Apache::lonnet::coursedescription($short);
+    my %cenv=&Apache::lonnet::coursedescription($short,{'freshen_cache'=>1});
     my $fn=$cenv{'fn'};
     my $uri;
     $short=~s/\//\_/g;
     unless ($uri=$cenv{'url'}) { 
-	&Apache::lonnet::logthis("<font color=blue>WARNING: ".
+	&Apache::lonnet::logthis('<font color="blue">WARNING: '.
 				 "Could not load course $short.</font>"); 
-	return 'No course data available.';
+	return ('',&mt('No course data available.'));;
     }
     @cond=('true:normal');
-    #unlink($fn.'.db');
-    #unlink($fn.'_symb.db');
-    unlink($fn.'.state');
-    unlink($fn.'parms.db');
+
+    unless (open(LOCKFILE,">$fn.db.lock")) {
+        $errtext.='<br />'.&mt('Map not loaded - Lock file could not be opened when reading map:').' <tt>'.$fn.'</tt>.';
+        $retfurl = '';
+        return ($retfurl,$errtext);
+    }
+    my $lock=0;
+    my $gotstate=0;
+    if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) {
+	$lock=1;
+        &unlink_tmpfiles($fn);
+    }
     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})) {
-	    &Apache::lonnet::appenv("request.course.id"  => $short,
-				    "request.course.fn"  => $fn,
-				    "request.course.uri" => $uri);
-	    &traceroute('0',$hash{'map_start_'.$uri},'&');
-	    &accinit($uri,$short,$fn);
-	    &hiddenurls();
-	}
-# ------------------------------------------------------- Put versions into src
-	foreach (keys %hash) {
-	    if ($_=~/^src\_/) {
-		$hash{$_}=&putinversion($hash{$_});
-	    }
-	}
-# ---------------------------------------------------------------- Encrypt URLs
-	foreach (keys %encurl) {
-#	    $hash{'src_'.$_}=&Apache::lonenc::encrypted($hash{'src_'.$_});
-	    $hash{'encrypted_'.$_}=1;
-	}
-# ----------------------------------------------- Close hashes to finally store
-# --------------------------------- Routine must pass this point, no early outs
-	$hash{'first_url'}=$retfurl;
-	unless ((untie(%hash)) && (untie(%parmhash))) {
-	    &Apache::lonnet::logthis("<font color=blue>WARNING: ".
-				     "Could not untie coursemap $fn for $uri.</font>"); 
-	}
-# ---------------------------------------------------- Store away initial state
-	{
-	    my $cfh;
-	    if (open($cfh,">$fn.state")) {
-		print $cfh join("\n",@cond);
-	    } else {
-		&Apache::lonnet::logthis("<font color=blue>WARNING: ".
-					 "Could not write statemap $fn for $uri.</font>"); 
-	    }
-	}  
-    } else {
+    $retfrid='';
+    my ($untiedhash,$untiedparmhash,$tiedhash,$tiedparmhash);
+    if ($lock) {
+        if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) {
+            $tiedhash = 1;
+            if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640)) {
+                $tiedparmhash = 1;
+                $gotstate = &build_tmp_hashes($uri,$fn,$short,\%cenv);
+                unless ($gotstate) {
+                    &Apache::lonnet::logthis('Failed to write statemap at first attempt '.$fn.' for '.$uri.'.</font>');
+                }
+                $untiedparmhash = untie(%parmhash);
+                unless ($untiedparmhash) {
+                    &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                        'Could not untie coursemap parmhash '.$fn.' for '.$uri.'.</font>');
+                }
+            }
+            $untiedhash = untie(%hash);
+            unless ($untiedhash) {
+                &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                    'Could not untie coursemap hash '.$fn.' for '.$uri.'.</font>');
+            }
+        }
+	flock(LOCKFILE,LOCK_UN);
+    }
+    unless ($lock && $tiedhash && $tiedparmhash) { 
 	# if we are here it is likely because we are already trying to 
 	# initialize the course in another child, busy wait trying to 
 	# tie the hashes for the next 90 seconds, if we succeed forward 
 	# them on to navmaps, if we fail, throw up the Could not init 
 	# course screen
-	untie(%hash);
-	untie(%parmhash);
-	&Apache::lonnet::logthis("<font color=blue>WARNING: ".
-				 "Could not tie coursemap $fn for $uri.</font>"); 
+	if ($lock) {
+	    # Got the lock but not the DB files
+	    flock(LOCKFILE,LOCK_UN);
+            $lock = 0;
+	}
+        if ($tiedhash) {
+            unless($untiedhash) {
+	        untie(%hash);
+            }
+        }
+        if ($tiedparmhash) {
+            unless($untiedparmhash) {
+                untie(%parmhash);
+            }
+        }
+	&Apache::lonnet::logthis('<font color="blue">WARNING: '.
+				 "Could not tie coursemap $fn for $uri.</font>");
+        $tiedhash = '';
+        $tiedparmhash = '';
 	my $i=0;
 	while($i<90) {
 	    $i++;
 	    sleep(1);
-	    if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640))) {
-		if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_READER(),0640)) {
-		    $retfurl='/adm/navmaps';
-		    &Apache::lonnet::appenv("request.course.id"  => $short,
-					    "request.course.fn"  => $fn,
-					    "request.course.uri" => $uri);
-		    untie(%hash);
-		    untie(%parmhash);
-		    last;
-		}
-	    }
-	    untie(%hash);
-	    untie(%parmhash);
+	    if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) {
+                $lock = 1;
+		if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640)) {
+                    $tiedhash = 1;
+		    if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_READER(),0640)) {
+                        $tiedparmhash = 1;
+                        if (-e "$fn.state") {
+		            $retfurl='/adm/navmaps';
+		            &Apache::lonnet::appenv({"request.course.id"  => $short,
+		   			             "request.course.fn"  => $fn,
+					             "request.course.uri" => $uri});
+		            $untiedhash = untie(%hash);
+		            $untiedparmhash = untie(%parmhash);
+                            $gotstate = 1;
+		            last;
+		        }
+                        $untiedparmhash = untie(%parmhash);
+	            }
+	            $untiedhash = untie(%hash);
+                }
+            }
 	}
+        if ($lock) {
+            flock(LOCKFILE,LOCK_UN);
+            $lock = 0;
+            if ($tiedparmhash) {
+                unless ($untiedparmhash) {
+                    &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                        'Could not untie coursemap parmhash '.$fn.' for '.$uri.'.</font>');
+                }
+            }
+            if ($tiedparmhash) {
+                unless ($untiedhash) {
+                    &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                        'Could not untie coursemap hash '.$fn.' for '.$uri.'.</font>');
+                }
+            }
+        }
+    }
+    unless ($gotstate) {
+        $lock = 0;
+        &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                     'Could not read statemap '.$fn.' for '.$uri.'.</font>');
+        &unlink_tmpfiles($fn);
+        if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) {
+            $lock=1;
+        }
+        undef %randompick;
+        undef %hiddenurl;
+        undef %encurl;
+        $retfrid='';
+        if ($lock) {
+            if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) {
+                if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640)) {
+                    $gotstate = &build_tmp_hashes($uri,$fn,$short,\%cenv);
+                    unless ($gotstate) {
+                        &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                            'Failed to write statemap at second attempt '.$fn.' for '.$uri.'.</font>');
+                    }
+                    unless (untie(%parmhash)) {
+                        &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                            'Could not untie coursemap parmhash '.$fn.'.db for '.$uri.'.</font>');
+                    }
+                } else {
+                    &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                        'Could not tie coursemap '.$fn.'__parms.db for '.$uri.'.</font>');
+                }
+                unless (untie(%hash)) {
+                    &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                        'Could not untie coursemap hash '.$fn.'.db for '.$uri.'.</font>');
+                }
+            } else {
+               &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+                   'Could not tie coursemap '.$fn.'.db for '.$uri.'.</font>');
+            }
+            flock(LOCKFILE,LOCK_UN);
+            $lock = 0;
+        } else {
+            &Apache::lonnet::logthis('<font color="blue">WARNING: '.
+            'Could not obtain lock to tie coursemap hash '.$fn.'.db for '.$uri.'.</font>');
+        }
+    }
+    close(LOCKFILE);
+    unless (($errtext eq '') || ($env{'request.course.uri'} =~ m{^/uploaded/})) {
+        &Apache::lonmsg::author_res_msg($env{'request.course.uri'},
+                                        $errtext);
     }
-    &Apache::lonmsg::author_res_msg($env{'request.course.uri'},$errtext);
 # ------------------------------------------------- Check for critical messages
 
     my @what=&Apache::lonnet::dump('critical',$env{'user.domain'},
@@ -648,6 +835,91 @@ sub readmap {
     return ($retfurl,$errtext);
 }
 
+sub build_tmp_hashes {
+    my ($uri,$fn,$short,$cenvref) = @_;
+    unless(ref($cenvref) eq 'HASH') {
+        return;
+    }
+    my %cenv = %{$cenvref};
+    my $gotstate = 0;
+    %hash=();
+    %parmhash=();
+    $errtext='';
+    $pc=0;
+    &clear_mapalias_count();
+    &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,'0.0');
+    if (defined($hash{'map_start_'.$uri})) {
+        &Apache::lonnet::appenv({"request.course.id"  => $short,
+                                 "request.course.fn"  => $fn,
+                                 "request.course.uri" => $uri});
+        $env{'request.course.id'}=$short;
+        &traceroute('0',$hash{'map_start_'.$uri},'&');
+        &accinit($uri,$short,$fn);
+        &hiddenurls();
+    }
+    $errtext .= &get_mapalias_errors();
+# ------------------------------------------------------- Put versions into src
+    foreach my $key (keys(%hash)) {
+        if ($key=~/^src_/) {
+            $hash{$key}=&putinversion($hash{$key});
+        } elsif ($key =~ /^(map_(?:start|finish|pc)_)(.*)/) {
+            my ($type, $url) = ($1,$2);
+            my $value = $hash{$key};
+            $hash{$type.&putinversion($url)}=$value;
+        }
+    }
+# ---------------------------------------------------------------- Encrypt URLs
+    foreach my $id (keys(%encurl)) {
+#           $hash{'src_'.$id}=&Apache::lonenc::encrypted($hash{'src_'.$id});
+        $hash{'encrypted_'.$id}=1;
+    }
+# ----------------------------------------------- Close hashes to finally store
+# --------------------------------- Routine must pass this point, no early outs
+    $hash{'first_rid'}=$retfrid;
+    my ($mapid,$resid)=split(/\./,$retfrid);
+    $hash{'first_mapurl'}=$hash{'map_id_'.$mapid};
+    my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,$hash{'src_'.$retfrid});
+    $retfurl=&add_get_param($hash{'src_'.$retfrid},{ 'symb' => $symb });
+    if ($hash{'encrypted_'.$retfrid}) {
+        $retfurl=&Apache::lonenc::encrypted($retfurl,(&Apache::lonnet::allowed('adv') ne 'F'));
+    }
+    $hash{'first_url'}=$retfurl;
+# ---------------------------------------------------- Store away initial state
+    {
+        my $cfh;
+        if (open($cfh,">$fn.state")) {
+            print $cfh join("\n",@cond);
+            $gotstate = 1;
+        } else {
+            &Apache::lonnet::logthis("<font color=blue>WARNING: ".
+                                     "Could not write statemap $fn for $uri.</font>");
+        }
+    }
+    return $gotstate;
+}
+
+sub unlink_tmpfiles {
+    my ($fn) = @_;
+    if ($fn =~ m{^\Q$Apache::lonnet::perlvar{'lonDaemons'}\E/tmp/}) {
+        my @files = qw (.db _symb.db .state _parms.db);
+        foreach my $file (@files) {
+            if (-e $fn.$file) {
+                unless (unlink($fn.$file)) {
+                    &Apache::lonnet::logthis("<font color=blue>WARNING: ".
+                                 "Could not unlink ".$fn.$file."</font>");
+                }
+            }
+        }
+    }
+    return;
+}
+
 # ------------------------------------------------------- Evaluate state string
 
 sub evalstate {
@@ -656,8 +928,9 @@ sub evalstate {
     if (-e $fn) {
 	my @conditions=();
 	{
-	    my $fh=Apache::File->new($fn);
+	    open(my $fh,"<$fn");
 	    @conditions=<$fh>;
+            close($fh);
 	}  
 	my $safeeval = new Safe;
 	my $safehole = new Safe::Hole;
@@ -683,10 +956,47 @@ sub evalstate {
 	    }
 	}
     }
-    &Apache::lonnet::appenv('user.state.'.$env{'request.course.id'} => $state);
+    &Apache::lonnet::appenv({'user.state.'.$env{'request.course.id'} => $state});
     return $state;
 }
 
+{
+    my %mapalias_cache;
+    sub count_mapalias {
+	my ($value,$resid) = @_;
+ 	push(@{ $mapalias_cache{$value} }, $resid);
+    }
+
+    sub get_mapalias_errors {
+	my $error_text;
+	foreach my $mapalias (sort(keys(%mapalias_cache))) {
+	    next if (scalar(@{ $mapalias_cache{$mapalias} } ) == 1);
+	    my $count;
+	    my $which =
+		join('</li><li>', 
+		     map {
+			 my $id = $_;
+			 if (exists($hash{'src_'.$id})) {
+			     $count++;
+			 }
+			 my ($mapid) = split(/\./,$id);
+                         &mt('Resource "[_1]" <br /> in Map "[_2]"',
+			     $hash{'title_'.$id},
+			     $hash{'title_'.$hash{'ids_'.$hash{'map_id_'.$mapid}}});
+		     } (@{ $mapalias_cache{$mapalias} }));
+	    next if ($count < 2);
+	    $error_text .= '<div class="LC_error">'.
+		&mt('Error: Found the mapalias "[_1]" defined multiple times.',
+		    $mapalias).
+		'</div><ul><li>'.$which.'</li></ul>';
+	}
+	&clear_mapalias_count();
+	return $error_text;
+    }
+    sub clear_mapalias_count {
+	undef(%mapalias_cache);
+    }
+}
 1;
 __END__
 
@@ -709,37 +1019,33 @@ 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
+=head1 SUBROUTINES
 
-=over 4
+=over
 
-=item *
+=item loadmap()
 
-loadmap() : Loads map from disk
+Loads map from disk
 
-=item *
+=item simplify()
 
-simplify() : Simplify expression
+Simplify expression
 
-=item *
+=item traceroute()
 
-traceroute() : Build condition hash
+Build condition hash
 
-=item *
+=item accinit()
 
-accinit() : Cascading conditions, quick access, parameters
+Cascading conditions, quick access, parameters
 
-=item *
+=item readmap()
 
-readmap() : Read map and all submaps
+Read map and all submaps
 
-=item *
+=item evalstate()
 
-evalstate() : Evaluate state string
+Evaluate state string
 
 =back