Diff for /rat/lonuserstate.pm between versions 1.16 and 1.159

version 1.16, 2000/11/02 15:53:17 version 1.159, 2020/04/22 14:52:56
Line 1 Line 1
 # The LearningOnline Network with CAPA  # The LearningOnline Network with CAPA
 # Construct and maintain state and binary representation of course for user  # Construct and maintain state and binary representation of course for user
 #  #
 # (Server for RAT Maps  # $Id$
 #  #
 # (Edit Handler for RAT Maps  # Copyright Michigan State University Board of Trustees
 # (TeX Content Handler  
 #  #
 # 05/29/00,05/30 Gerd Kortemeyer)  # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
 # 7/1 Gerd Kortemeyer)  
 # 7/1,7/3,7/4,7/7,7/8,7/10 Gerd Kortemeyer)  
 #  #
 # 7/15,7/17,7/18,8/1,8/2,8/4,8/5,8/21,8/22,8/23,8/30,  # LON-CAPA is free software; you can redistribute it and/or modify
 # 9/2,9/4,9/29,9/30,10/2,10/11,10/30,10/31,11/1,11/2 Gerd Kortemeyer  # 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;  package Apache::lonuserstate;
   
   # ------------------------------------------------- modules used by this module
 use strict;  use strict;
 use Apache::Constants qw(:common :http);  
 use Apache::File;  
 use HTML::TokeParser;  use HTML::TokeParser;
 use Apache::lonnet();  use Apache::lonnet;
   use Apache::lonlocal;
   use Apache::loncommon();
 use GDBM_File;  use GDBM_File;
 use Apache::lonmsg;  use Apache::lonmsg;
 use Safe;  use Safe;
   use Safe::Hole;
 use Opcode;  use Opcode;
   use Apache::lonenc;
   use Fcntl qw(:flock);
   use LONCAPA qw(:DEFAULT :match);
   use File::Basename;
   
    
   
 # ---------------------------------------------------- Globals for this package  # ---------------------------------------------------- Globals for this package
   
 my $pc;      # Package counter  my $pc;      # Package counter is this what 'Guts' calls the map counter?
 my %hash;    # The big tied hash  my %hash;    # The big tied hash
   my %parmhash;# The hash with the parameters
 my @cond;    # Array with all of the conditions  my @cond;    # Array with all of the conditions
 my $errtext; # variable with all errors  my $errtext; # variable with all errors
   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 %randomizationcode; # code used to grade folder for bubblesheet exam 
   my %encurl; # URLs in this folder are supposed to be encrypted
   my %hiddenurl; # this URL (or complete folder) is supposed to be hidden
   my %deeplinkonly; # this URL (or complete folder) is deep-link only
   my %rescount; # count of unhidden items in each map
   my %mapcount; # count of unhidden maps in each map
   
   # ----------------------------------- 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 />';
   }
   
 # --------------------------------------------------------- Loads map from disk  #  Removes the version number from a URI and returns the resulting
   #  URI (e.g. mumbly.version.stuff => mumbly.stuff).
   #
   #   If the URI has not been seen with a versio before the
   #   hash{'version_'.resultingURI} is set to the  version number.
   #   If the URI has been seen and the version does not match and error
   #   is added to the error string.
   #
   # Parameters:
   #   URI potentially with a version.
   # Returns:
   #   URI with the version cut out.
   # See above for side effects.
   #
   
 sub loadmap {   sub versiontrack {
     my $uri=shift;      my $uri=shift;
     if ($hash{'map_pc_'.$uri}) { return OK; }      if ($uri=~/\.(\d+)\.\w+$/) {
    my $version=$1;
    $uri=~s/\.\d+\.(\w+)$/\.$1/;
           unless ($hash{'version_'.$uri}) {
       $hash{'version_'.$uri}=$version;
    } elsif ($version!=$hash{'version_'.$uri}) {
               $errtext.=&versionerror($uri,$hash{'version_'.$uri},$version);
           }
       }
       return $uri;
   }
   
   # -------------------------------------------------------------- Put in version
   
   sub putinversion {
       my $uri=shift;
       my $key=$env{'request.course.id'}.'_'.&Apache::lonnet::clutter($uri);
       if ($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\.$1/;
       }
       &Apache::lonnet::do_cache_new('courseresversion',$key,&Apache::lonnet::declutter($uri),600);
       return $uri;
   }
   
   # ----------------------------------------- Processing versions file for course
   
   sub processversionfile {
       my %cenv=@_;
       my %versions=&Apache::lonnet::dump('resourceversions',
          $cenv{'domain'},
          $cenv{'num'});
       foreach my $ver (keys(%versions)) {
    if ($ver=~/^error\:/) { return; }
    $hash{'version_'.$ver}=$versions{$ver};
       }
   }
   
   # --------------------------------------------------------- Loads from disk
   
   
   #
   #  Loads a map file.
   #  Note that this may implicitly recurse via parse_resource if one of the resources
   #  is itself composed.
   #
   # Parameters:
   #    uri         - URI of the map file.
   #    parent_rid  - Resource id in the map of the parent resource (0.0 for the top level map)
   #    courseid    - Course id for the course for which the map is being loaded
   #
   sub loadmap { 
       my ($uri,$parent_rid,$courseid)=@_;
   
       # Is the map already included?
   
       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; 
       }
       # Register the resource in it's map_pc_ [for the URL]
       # map_id.nnn is the nesting level -> to the URI.
   
     $pc++;      $pc++;
     my $lpc=$pc;      my $lpc=$pc;
     $hash{'map_pc_'.$uri}=$lpc;      $hash{'map_pc_'.$uri}=$lpc;
     $hash{'map_id_'.$lpc}=$uri;      $hash{'map_id_'.$lpc}=$uri;
   
     my $fn='/home/httpd/html'.$uri;      # If the parent is of the form n.m hang this map underneath it in the
       # map hierarchy.
   
     unless (($fn=~/\.sequence$/) ||      if ($parent_rid =~ /^(\d+)\.\d+$/) {
             ($fn=~/\.page$/)) {           my $parent_pc = $1;
        $errtext.="Invalid map: $fn\n";          if (defined($hash{'map_hierarchy_'.$parent_pc})) {
        return OK;               $hash{'map_hierarchy_'.$lpc}=$hash{'map_hierarchy_'.$parent_pc}.','.
     }                                           $parent_pc;
           } else {
     unless (-e $fn) {              $hash{'map_hierarchy_'.$lpc}=$parent_pc;
  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;  
        }  
     }      }
   
     if (-e $fn) {  # Determine and check filename of the sequence we need to read:
         my @content;  
         {  
     my $fh=Apache::File->new($fn);  
             @content=<$fh>;  
         }  
         my $instr=join('',@content);  
         my $parser = HTML::TokeParser->new(\$instr);  
         my $token;  
   
         my $linkpc=0;      my $fn=&Apache::lonnet::filelocation('',&putinversion($uri));
   
         $fn=~/\.(\w+)$/;      my $ispage=($fn=~/\.page$/);
   
         $hash{'map_type_'.$lpc}=$1;      # We can only nest sequences or pages.  Anything else is an illegal nest.
   
         while ($token = $parser->get_token) {      unless (($fn=~/\.sequence$/) || $ispage) { 
     if ($token->[0] eq 'S') {   $errtext.='<br />'.&mt('Invalid map: [_1]',"<tt>$fn</tt>");
                 if ($token->[1] eq 'resource') {   return; 
 # -------------------------------------------------------------------- Resource      }
   
                     my $rid=$lpc.'.'.$token->[2]->{'id'};      # Read the XML that constitutes the file.
   
                     $hash{'kind_'.$rid}='res';      my $instr=&Apache::lonnet::getfile($fn);
                     $hash{'title_'.$rid}=$token->[2]->{'title'};  
                     my $turi=$token->[2]->{'src'};  
                     $hash{'src_'.$rid}=$turi;  
   
                     if (defined($hash{'ids_'.$turi})) {      if ($instr eq -1) {
                         $hash{'ids_'.$turi}.=','.$rid;          $errtext.= '<br />'
                     } else {                    .&mt('Map not loaded: The file [_1] does not exist.',
                         $hash{'ids_'.$turi}=''.$rid;                         "<tt>$fn</tt>");
                     }   return;
       }
   
                     if ($token->[2]->{'src'}=~/\/\//) {      # Successfully got file, parse it
                         $hash{'ext_'.$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 (($turi=~/\.sequence$/) ||      # parse for parameter processing.
                         ($turi=~/\.page$/)) {      # Note that these are <param... / > tags
                         $hash{'is_map_'.$rid}=1;      # so we only care about 'S' (tag start) nodes.
                         &loadmap($turi);  
                     }   
                       
                 } elsif ($token->[1] eq 'condition') {  
 # ------------------------------------------------------------------- Condition  
   
                     my $rid=$lpc.'.'.$token->[2]->{'id'};  
   
                     $hash{'kind_'.$rid}='cond';      my $parser = HTML::TokeParser->new(\$instr);
                     $cond[$#cond+1]=$token->[2]->{'value'};      $parser->attr_encoded(1);
                     $hash{'condid_'.$rid}=$#cond;  
                     if ($token->[2]->{'type'}) {  
                         $cond[$#cond].=':'.$token->[2]->{'type'};  
                     }  else {  
                         $cond[$#cond].=':normal';  
                     }  
   
                 } elsif ($token->[1] eq 'link') {      # first get all parameters
 # ----------------------------------------------------------------------- Links  
   
                     $linkpc++;  
                     my $linkid=$lpc.'.'.$linkpc;  
   
                     my $goesto=$lpc.'.'.$token->[2]->{'to'};      while (my $token = $parser->get_token) {
                     my $comesfrom=$lpc.'.'.$token->[2]->{'from'};   next if ($token->[0] ne 'S');
                     my $undercond=0;   if ($token->[1] eq 'param') {
       &parse_param($token,$lpc);
    } 
       }
   
                     if ($token->[2]->{'condition'}) {      # Get set to take another pass through the XML:
  $undercond=$lpc.'.'.$token->[2]->{'condition'};      # for resources and links.
                     }  
   
                     $hash{'goesto_'.$linkid}=$goesto;      $parser = HTML::TokeParser->new(\$instr);
                     $hash{'comesfrom_'.$linkid}=$comesfrom;      $parser->attr_encoded(1);
                     $hash{'undercond_'.$linkid}=$undercond;  
   
                     if (defined($hash{'to_'.$comesfrom})) {      my $linkpc=0;
                         $hash{'to_'.$comesfrom}.=','.$linkid;  
                     } else {      $fn=~/\.(\w+)$/;
                         $hash{'to_'.$comesfrom}=''.$linkid;  
       $hash{'map_type_'.$lpc}=$1;
   
       my $randomize = ($randomorder{$parent_rid} =~ /^yes$/i);
   
       # Parse the resources, link and condition tags.
       # Note that if randomorder or random select is chosen the links and
       # conditions are meaningless but are determined by the randomization.
       # This is handled in the next chunk of code.
   
       my @map_ids;
       my $codechecked;
       $rescount{$lpc} = 0;
       $mapcount{$lpc} = 0;
       while (my $token = $parser->get_token) {
    next if ($token->[0] ne 'S');
   
    # Resource
   
    if ($token->[1] eq 'resource') {
       my $resource_id = &parse_resource($token,$lpc,$ispage,$uri,$courseid);
       if (defined $resource_id) {
    push(@map_ids, $resource_id);
                   if ($hash{'src_'.$lpc.'.'.$resource_id}) {
                       $rescount{$lpc} ++;
                       if (($hash{'src_'.$lpc.'.'.$resource_id}=~/\.sequence$/) || 
                           ($hash{'src_'.$lpc.'.'.$resource_id}=~/\.page$/)) {
                           $mapcount{$lpc} ++; 
                     }                      }
                     if (defined($hash{'from_'.$goesto})) {                  }
                         $hash{'from_'.$goesto}.=','.$linkid;                  unless ($codechecked) {
                     } else {                      my $startsymb =
                         $hash{'from_'.$goesto}=''.$linkid;                         &Apache::lonnet::encode_symb($hash{'map_id_'.$lpc},$resource_id,
                                                       $hash{'src_'."$lpc.$resource_id"});
                       my $code = 
                           &Apache::lonnet::EXT('resource.0.examcode',$startsymb,undef,undef,
                                                undef,undef,$courseid);
                       if ($code) {
                           $randomizationcode{$parent_rid} = $code;
                     }                      }
                 }                       $codechecked = 1; 
                   }
       }
   
          # Link
   
    } elsif ($token->[1] eq 'link' && !$randomize) {
       &make_link(++$linkpc,$lpc,$token->[2]->{'to'},
          $token->[2]->{'from'},
          $token->[2]->{'condition'}); # note ..condition may be undefined.
   
    # condition
   
    } elsif ($token->[1] eq 'condition' && !$randomize) {
       &parse_condition($token,$lpc);
    }
       }
       undef($codechecked);
   
       # Handle randomization and random selection
   
       if ($randomize) {
           unless (&is_advanced($courseid)) {
               # Order of resources is not randomized if user has and advanced role in the course.
       my $seed;
   
               # If the map's random seed parameter has been specified
               # it is used as the basis for computing the seed ...
   
       if (defined($randompickseed{$parent_rid})) {
    $seed = $randompickseed{$parent_rid};
       } else {
   
    # Otherwise the parent's fully encoded symb is used.
   
    my ($mapid,$resid)=split(/\./,$parent_rid);
    my $symb=
       &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
    $resid,$hash{'src_'.$parent_rid});
   
    $seed = $symb;
       }
   
       # TODO: Here for sure we need to pass along the username/domain
       # so that we can impersonate users in lonprintout e.g.
   
               my $setcode;
               if (defined($randomizationcode{$parent_rid})) {
                   if ($env{'form.CODE'} eq '') {
                       $env{'form.CODE'} = $randomizationcode{$parent_rid};
                       $setcode = 1;
                   }
             }              }
   
       my $rndseed=&Apache::lonnet::rndseed($seed);
       &Apache::lonnet::setup_random_from_rndseed($rndseed);
   
               if ($setcode) {
                   undef($env{'form.CODE'});
                   undef($setcode);
               }
   
       # Take the set of map ids we have decoded and permute them to a
       # random order based on the seed set above. All of this is
       # processing the randomorder parameter if it is set, not
       # randompick.
   
       @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';
   
    # Create links to reflect the random re-ordering done above.
    # In the code to process the map XML, we did not process links or conditions
    # if randomorder was set.  This means that for an instructor to choose
   
    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;
    }
   
    $hash{'map_finish_'.$uri}= $from_rid;
    $hash{'type_'.$from_rid}='finish';
       }
   
       $parser = HTML::TokeParser->new(\$instr);
       $parser->attr_encoded(1);
   
       # last parse out the mapalias params.  These provide mnemonic
       # tags to resources that can be used in conditions
   
       while (my $token = $parser->get_token) {
    next if ($token->[0] ne 'S');
    if ($token->[1] eq 'param') {
       &parse_mapalias_param($token,$lpc);
    } 
       }
   }
   
   sub is_advanced {
       my ($courseid) = @_;
       my $advanced;
       if ($env{'request.course.id'}) {
           $advanced = (&Apache::lonnet::allowed('adv') eq 'F');
       } else {
           $env{'request.course.id'} = $courseid;
           $advanced = (&Apache::lonnet::allowed('adv') eq 'F');
           $env{'request.course.id'} = '';
       }
       return $advanced;
   }
   
   # -------------------------------------------------------------------- Resource
   #
   #  Parses a resource tag to produce the value to push into the
   #  map_ids array.
   # 
   #
   #  Information about the actual type of resource is provided by the file extension
   #  of the uri (e.g. .problem, .sequence etc. etc.).
   #
   #  Parameters:
   #    $token   - A token from HTML::TokeParser
   #               This is an array that describes the most recently parsed HTML item.
   #    $lpc     - Map nesting level (?)
   #    $ispage  - True if this resource is encapsulated in a .page (assembled resourcde).
   #    $uri     - URI of the enclosing resource.
   #    $courseid - Course id of the course containing the resource being parsed. 
   # Returns:
   #   Value of the id attribute of the tag.
   #
   # Note:
   #   The token is an array that contains the following elements:
   #   [0]   => 'S' indicating this is a start token
   #   [1]   => 'resource'  indicating this tag is a <resource> tag.
   #   [2]   => Hash of attribute =>value pairs.
   #   [3]   => @(keys [2]).
   #   [4]   => unused.
   #
   #   The attributes of the resourcde tag include:
   #
   #   id     - The resource id.
   #   src    - The URI of the resource.
   #   type   - The resource type (e.g. start and finish).
   #   title  - The resource title.
   
   
   sub parse_resource {
       my ($token,$lpc,$ispage,$uri,$courseid) = @_;
       
       # I refuse to countenance code like this that has 
       # such a dirty side effect (and forcing this sub to be called within a loop).
       #
       #  if ($token->[2]->{'type'} eq 'zombie') { next; }
       #
       #  The original code both returns _and_ skips to the next pass of the >caller's<
       #  loop, that's just dirty.
       #
   
       # Zombie resources don't produce anything useful.
   
       if ($token->[2]->{'type'} eq 'zombie') {
    return undef;
       }
   
       my $rid=$lpc.'.'.$token->[2]->{'id'}; # Resource id in hash is levelcounter.id-in-xml.
   
       # Save the hash element type and title:
       
       $hash{'kind_'.$rid}='res';
       $hash{'title_'.$rid}=$token->[2]->{'title'};
   
       # Get the version free URI for the resource.
       # If a 'version' attribute was supplied, and this resource's version 
       # information has not yet been stored, store it.
       #
   
       my $turi=&versiontrack($token->[2]->{'src'});
       if ($token->[2]->{'version'}) {
    unless ($hash{'version_'.$turi}) {
       $hash{'version_'.$turi}=$1;
    }
       }
       # Pull out the title and do entity substitution on &colon
       # Q: Why no other entity substitutions?
   
       my $title=$token->[2]->{'title'};
       $title=~s/\&colon\;/\:/gs;
   
   
   
       # I think the point of all this code is to construct a final
       # URI that apache and its rewrite rules can use to
       # fetch the resource.   Thi s sonly necessary if the resource
       # is not a page.  If the resource is a page then it must be
       # assembled (at fetch time?).
   
       if ($ispage) {
           if ($token->[2]->{'external'} eq 'true') { # external
               $turi=~s{^http\://}{/ext/};
         }          }
       } else {
    $turi=~/\.(\w+)$/;
    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 ($turi=~ m{^/adm/$match_domain/$match_courseid/\d+/ext\.tool$}) {
               $turi='/adm/wrapper'.$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 resource 'ids'_uri => resource id.
       # If the URI appears more than one time in the sequence, it's resourcde
       # id's are constructed as a comma spearated list.
   
       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';
       }
       
   
       # resource id lookup:  'src'_resourc-di  => URI decorated with a query
       # parameter as above if necessary due to the resource type.
       
       $hash{'src_'.$rid}=$turi;
   
       # Mark the external-ness of the resource:
       
       if ($token->[2]->{'external'} eq 'true') {
    $hash{'ext_'.$rid}='true:';
     } else {      } else {
         $errtext.='Map not loaded: The file does not exist. ';   $hash{'ext_'.$rid}='false:';
       }
   
       # If the resource is a start/finish resource set those
       # entries in the has so that navigation knows where everything starts.
       # TODO?  If there is a malformed sequence that has no start or no finish
       # resource, should this be detected and errors thrown?  How would such a 
       # resource come into being other than being manually constructed by a person
       # and then uploaded?  Could that happen if an author decided a sequence was almost
       # right edited it by hand and then reuploaded it to 'fix it' but accidently cut the
       #  start or finish resources?
       #
       #  All resourcess also get a type_id => (start | finish | normal)    hash entr.
       #
       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';
       }
   
       # Sequences end pages are constructed entities.  They require that the 
       # map that defines _them_ be loaded as well into the hash...with this resourcde
       # as the base of the nesting.
       # Resources like that are also marked with is_map_id => 1 entries.
       #
       
       if (($turi=~/\.sequence$/) ||
    ($turi=~/\.page$/)) {
    $hash{'is_map_'.$rid}=1;
    if ((&is_advanced($courseid)) || (!$hiddenurl{$rid})) {
       &loadmap($turi,$rid,$courseid);
    }
       } 
       return $token->[2]->{'id'};
   }
   
   #-------------------------------------------------------------------- link
   #  Links define how you are allowed to move from one resource to another.
   #  They are the transition edges in the directed graph that a map is.
   #  This sub takes informatino from a <link> tag and constructs the
   #  navigation bits and pieces of a map.  There is no requirement that the
   #  resources that are linke are already defined, however clearly the map is 
   #  badly broken if they are not _eventually_ defined.
   #
   #  Note that links can be unconditional or conditional.
   #
   #  Parameters:
   #     linkpc   - The link counter for this level of map nesting (this is 
   #                reset to zero by loadmap prior to starting to process
   #                links for map).
   #     lpc      - The map level ocounter (how deeply nested this map is in
   #                the hierarchy of maps that are recursively read in.
   #     to       - resource id (within the XML) of the target of the edge.
   #     from     - resource id (within the XML) of the source of the edge.
   #     condition- id of condition associated with the edge (also within the XML).
   #
   
   sub make_link {
       my ($linkpc,$lpc,$to,$from,$condition) = @_;
       
       #  Compute fully qualified ids for the link, the 
       # and from/to by prepending lpc.
       #
   
       my $linkid=$lpc.'.'.$linkpc;
       my $goesto=$lpc.'.'.$to;
       my $comesfrom=$lpc.'.'.$from;
       my $undercond=0;
   
   
       # If there is a condition, qualify it with the level counter.
   
       if ($condition) {
    $undercond=$lpc.'.'.$condition;
       }
   
       # Links are represnted by:
       #  goesto_.fuullyqualifedlinkid => fully qualified to
       #  comesfrom.fullyqualifiedlinkid => fully qualified from
       #  undercond_.fullyqualifiedlinkid => fully qualified condition id.
   
       $hash{'goesto_'.$linkid}=$goesto;
       $hash{'comesfrom_'.$linkid}=$comesfrom;
       $hash{'undercond_'.$linkid}=$undercond;
   
       # In addition:
       #   to_.fully qualified from => comma separated list of 
       #   link ids with that from.
       # Similarly:
       #   from_.fully qualified to => comma separated list of link ids`
       #                               with that to.
       #  That allows us given a resource id to know all edges that go to it
       #  and leave from it.
       #
   
       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;
       }
   }
   
   # ------------------------------------------------------------------- Condition
   #
   #  Processes <condition> tags, storing sufficient information about them
   #  in the hash so that they can be evaluated and used to conditionalize
   #  what is presented to the student.
   #
   #  these can have the following attributes 
   #
   #    id    = A unique identifier of the condition within the map.
   #
   #    value = Is a perl script-let that, when evaluated in safe space
   #            determines whether or not the condition is true.
   #            Normally this takes the form of a test on an  Apache::lonnet::EXT call
   #            to find the value of variable associated with a resource in the
   #            map identified by a mapalias.
   #            Here's a fragment of XML code that illustrates this:
   #
   #           <param to="5" value="mainproblem" name="parameter_0_mapalias" type="string" />
   #           <resource src="" id="1" type="start" title="Start" />
   #           <resource src="/res/msu/albertel/b_and_c/p1.problem" id="5"  title="p1.problem" />
   #           <condition value="&EXT('user.resource.resource.0.tries','mainproblem')
   #           <2 " id="61" type="stop" />
   #           <link to="5" index="1" from="1" condition="61" />    
   #
   #           In this fragment:
   #             - The param tag establishes an alias to resource id 5 of 'mainproblem'.
   #             - The resource that is the start of the map is identified.
   #             - The resource tag identifies the resource associated with this tag
   #               and gives it the id 5.
   #             - The condition is true if the tries variable associated with mainproblem
   #               is less than 2 (that is the user has had more than 2 tries).
   #               The condition type is a stop condition which inhibits(?) the associated
   #               link if the condition  is false. 
   #             - The link to resource 5 from resource 1 is affected by this condition.    
   #            
   #    type  = Type of the condition. The type determines how the condition affects the
   #            link associated with it and is one of
   #            -  'force'
   #            -  'stop'
   #              anything else including not supplied..which treated as:
   #            - 'normal'.
   #            Presumably maps get created by the resource assembly tool and therefore
   #            illegal type values won't squirm their way into the XML.
   #
   # Side effects:
   #   -  The kind_level-qualified-condition-id hash element is set to 'cond'.
   #   -  The condition text is pushed into the cond array and its element number is
   #      set in the condid_level-qualified-condition-id element of the hash.
   #   - The condition type is colon appneded to the cond array element for this 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';
       }
   }
   
   # ------------------------------------------------------------------- Parameter
   # Parse a <parameter> tag in the map.
   # Parmameters:
   #    $token Token array for a start tag from HTML::TokeParser
   #           [0] = 'S'
   #           [1] = tagname ("param")
   #           [2] = Hash of {attribute} = values.
   #           [3] = Array of the keys in [2].
   #           [4] = unused.
   #    $lpc   Current map nesting level.a
   #
   #  Typical attributes:
   #     to=n      - Number of the resource the parameter applies to.
   #     type=xx   - Type of parameter value (e.g. string_yesno or int_pos).
   #     name=xxx  - Name of parameter (e.g. parameter_randompick or parameter_randomorder).
   #     value=xxx - value of the parameter.
   
   sub parse_param {
       my ($token,$lpc) = @_;
       my $referid=$lpc.'.'.$token->[2]->{'to'}; # Resource param applies to.
       my $name=$token->[2]->{'name'};      # Name of parameter
       my $part;
   
   
       if ($name=~/^parameter_(.*)_/) { 
    $part=$1;
       } else {
    $part=0;
       }
   
       # Peel the parameter_ off the parameter name.
   
       $name=~s/^.*_([^_]*)$/$1/;
   
       # The value is:
       #   type.part.name.value
   
       my $newparam=
    &escape($token->[2]->{'type'}).':'.
    &escape($part.'.'.$name).'='.
    &escape($token->[2]->{'value'});
   
       # The hash key is param_resourceid.
       # Multiple parameters for a single resource are & separated in the hash.
   
   
       if (defined($hash{'param_'.$referid})) {
    $hash{'param_'.$referid}.='&'.$newparam;
       } else {
    $hash{'param_'.$referid}=''.$newparam;
       }
       #
       #  These parameters have to do with randomly selecting
       # resources, therefore a separate hash is also created to 
       # make it easy to locate them when actually computing the resource set later on
       # See the code conditionalized by ($randomize) in loadmap().
   
       if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) { # Random selection turned on
    $randompick{$referid}=$token->[2]->{'value'};
       }
       if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) { # Randomseed provided.
    $randompickseed{$referid}=$token->[2]->{'value'};
       }
       if ($token->[2]->{'name'}=~/^parameter_(0_)*randomorder$/) { # Random order turned on.
    $randomorder{$referid}=$token->[2]->{'value'};
       }
   
       # These parameters have to do with how the URLs of resources are presented to
       # course members(?).  encrypturl presents encypted url's while
       # hiddenresource hides the URL.
       #
   
       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;
    }
       }
   }
   #
   #  Parse mapalias parameters.
   #  these are tags of the form:
   #  <param to="nn" 
   #         value="some-alias-for-resourceid-nn" 
   #         name="parameter_0_mapalias" 
   #         type="string" />
   #  A map alias is a textual name for a resource:
   #    - The to  attribute identifies the resource (this gets level qualified below)
   #    - The value attributes provides the alias string.
   #    - name must be of the regexp form: /^parameter_(0_)*mapalias$/
   #    - e.g. the string 'parameter_' followed by 0 or more "0_" strings
   #      terminating with the string 'mapalias'.
   #      Examples:
   #         'parameter_mapalias', 'parameter_0_mapalias', parameter_0_0_mapalias'
   #  Invalid to ids are silently ignored.
   #
   #  Parameters:
   #     token - The token array fromthe HMTML::TokeParser
   #     lpc   - The current map level counter.
   #
   sub parse_mapalias_param {
       my ($token,$lpc) = @_;
   
       # Fully qualify the to value and ignore the alias if there is no
       # corresponding resource.
   
       my $referid=$lpc.'.'.$token->[2]->{'to'};
       return if (!exists($hash{'src_'.$referid}));
   
       # If this is a valid mapalias parameter, 
       # Append the target id to the count_mapalias element for that
       # alias so that we can detect doubly defined aliases
       # e.g.:
       #  <param to="1" value="george" name="parameter_0_mapalias" type="string" />
       #  <param to="2" value="george" name="parameter_0_mapalias" type="string" />
       #
       #  The example above is trivial but the case that's important has to do with
       #  constructing a map that includes a nested map where the nested map may have
       #  aliases that conflict with aliases established in the enclosing map.
       #
       # ...and create/update the hash mapalias entry to actually store the alias.
       #
   
       if ($token->[2]->{'name'}=~/^parameter_(0_)*mapalias$/) {
    &count_mapalias($token->[2]->{'value'},$referid);
    $hash{'mapalias_'.$token->[2]->{'value'}}=$referid;
     }      }
 }  }
   
 # --------------------------------------------------------- Simplify expression  # --------------------------------------------------------- Simplify expression
   
   
   #
   #  Someone should really comment this to describe what it does to what and why.
   #
 sub simplify {  sub simplify {
    my $expression=shift;      my $expression=shift;
   # (0&1) = 1
       $expression=~s/\(0\&([_\.\d]+)\)/$1/g;
 # (8)=8  # (8)=8
    $expression=~s/\((\d+)\)/$1/g;      $expression=~s/\(([_\.\d]+)\)/$1/g;
 # 8&8=8  # 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  # 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  # (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))  # (((5&3)|(4&6)))=((5&3)|(4&6))
    $expression=~      $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)  # ((5&3)|(4&6))|(1&2)=(5&3)|(4&6)|(1&2)
    $expression=~      $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;      return $expression;
 }  }
   
 # -------------------------------------------------------- Build condition hash  # -------------------------------------------------------- Build condition hash
   
   #
   #  Traces a route recursively through the map after it has been loaded
   #  (I believe this really visits each resourcde that is reachable fromt he
   #  start top node.
   #
   #  - Marks hidden resources as hidden.
   #  - Marks which resource URL's must be encrypted.
   #  - Figures out (if necessary) the first resource in the map.
   #  - Further builds the chunks of the big hash that define how 
   #    conditions work
   #
   #  Note that the tracing strategy won't visit resources that are not linked to
   #  anything or islands in the map (groups of resources that form a path but are not
   #  linked in to the path that can be traced from the start resource...but that's ok
   #  because by definition, those resources are not reachable by users of the course.
   #
   # Parameters:
   #   sofar    - _URI of the prior entry or 0 if this is the top.
   #   rid      - URI of the resource to visit.
   #   beenhere - list of resources (each resource enclosed by &'s) that have
   #              already been visited.
   #   encflag  - If true the resource that resulted in a recursive call to us
   #              has an encoded URL (which means contained resources should too). 
   #   hdnflag  - If true,the resource that resulted in a recursive call to us
   #              was hidden (which means contained resources should be hidden too).
   # Returns
   #    new value indicating how far the map has been traversed (the sofar).
   #
 sub traceroute {  sub traceroute {
     my ($sofar,$rid,$beenhere)=@_;      my ($sofar,$rid,$beenhere,$encflag,$hdnflag)=@_;
     $sofar=simplify($sofar);      my $newsofar=$sofar=simplify($sofar);
     unless ($beenhere=~/\&$rid\&/) {  
        $beenhere.=$rid.'&';        unless ($beenhere=~/\&\Q$rid\E\&/) {
        if (defined($hash{'conditions_'.$rid})) {   $beenhere.=$rid.'&';  
    $hash{'conditions_'.$rid}=simplify(   my ($mapid,$resid)=split(/\./,$rid);
    my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,$hash{'src_'.$rid});
    my $hidden=&Apache::lonnet::EXT('resource.0.hiddenresource',$symb);
   
    if ($hdnflag || lc($hidden) eq 'yes') {
       $hiddenurl{$rid}=1;
    }
    if (!$hdnflag && lc($hidden) eq 'no') {
       delete($hiddenurl{$rid});
    }
   
    my $encrypt=&Apache::lonnet::EXT('resource.0.encrypturl',$symb);
    if ($encflag || lc($encrypt) eq 'yes') { $encurl{$rid}=1; }
   
    if (($retfrid eq '') && ($hash{'src_'.$rid})
       && ($hash{'src_'.$rid}!~/\.sequence$/)) {
       $retfrid=$rid;
    }
           my @deeplink=&Apache::lonnet::EXT('resource.0.deeplink',$symb);
           unless ((@deeplink == 0) || ($deeplink[0] eq 'full')) {
               $deeplinkonly{$rid}=join(':',@deeplink);
               if ($deeplink[1] eq 'map') {
                   my $parent = (split(/\,/,$hash{'map_hierarchy_'.$mapid}))[-1];
                   $deeplinkonly{"$parent.$mapid"}=$deeplinkonly{$rid};
               }
           }
   
    if (defined($hash{'conditions_'.$rid})) {
       $hash{'conditions_'.$rid}=simplify(
            '('.$hash{'conditions_'.$rid}.')|('.$sofar.')');             '('.$hash{'conditions_'.$rid}.')|('.$sofar.')');
        } else {   } else {
            $hash{'conditions_'.$rid}=$sofar;      $hash{'conditions_'.$rid}=$sofar;
        }   }
        if (defined($hash{'is_map_'.$rid})) {  
            if (defined($hash{'map_start_'.$hash{'src_'.$rid}})) {   # if the expression is just the 0th condition keep it
        &traceroute($sofar,$hash{'map_start_'.$hash{'src_'.$rid}},'&');   # otherwise leave a pointer to this condition expression
                if (defined($hash{'map_finish_'.$hash{'src_'.$rid}})) {  
    $sofar=   $newsofar = ($sofar eq '0') ? $sofar : '_'.$rid;
                   $hash{'conditions_'.$hash{'map_finish_'.$hash{'src_'.$rid}}};  
                }   # Recurse if the resource is a map:
            }  
        }   if (defined($hash{'is_map_'.$rid})) {
        if (defined($hash{'to_'.$rid})) {      if (defined($hash{'map_start_'.$hash{'src_'.$rid}})) {
           map {   $sofar=$newsofar=
       &traceroute($sofar,
    $hash{'map_start_'.$hash{'src_'.$rid}},
    $beenhere,
    $encflag || $encurl{$rid},
    $hdnflag || $hiddenurl{$rid});
       }
    }
   
    # Processes  links to this resource:
    #  - verify the existence of any conditionals on the link to here.
    #  - Recurse to any resources linked to us.
    #
    if (defined($hash{'to_'.$rid})) {
       foreach my $id (split(/\,/,$hash{'to_'.$rid})) {
  my $further=$sofar;   my $further=$sofar;
                 if ($hash{'undercond_'.$_}) {   #
    if (defined($hash{'condid_'.$hash{'undercond_'.$_}})) {   # If there's a condition associated with this link be sure
         $further=simplify('('.$further.')&('.   # it's been defined else that's an error:
                               $hash{'condid_'.$hash{'undercond_'.$_}}.')');   #
    } else {                  if ($hash{'undercond_'.$id}) {
                        $errtext.='Undefined condition ID: '      if (defined($hash{'condid_'.$hash{'undercond_'.$id}})) {
                                  .$hash{'undercond_'.$_}.'. ';   $further=simplify('('.'_'.$rid.')&('.
                    }    $hash{'condid_'.$hash{'undercond_'.$id}}.')');
                 }      } else {
                 &traceroute($further,$hash{'goesto_'.$_},$beenhere);   $errtext.= '<br />'.
           } split(/\,/,$hash{'to_'.$rid});                                     &mt('Undefined condition ID: [_1]',
        }                                         $hash{'undercond_'.$id});
       }
                   }
    #  Recurse to resoruces that have to's to us.
                   $newsofar=&traceroute($further,$hash{'goesto_'.$id},$beenhere,
         $encflag,$hdnflag);
       }
    }
     }      }
       return $newsofar;
 }  }
   
 # ------------------------------------------ Cascading conditions, quick access  # ------------------------------ Cascading conditions, quick access, parameters
   
   #
   #  Seems a rather strangely named sub given what the comment above says it does.
   
   
 sub accinit {  sub accinit {
     my ($uri,$short,$fn)=@_;      my ($uri,$short,$fn)=@_;
Line 247  sub accinit { Line 1004  sub accinit {
     my %captured=();      my %captured=();
     my $condcounter=0;      my $condcounter=0;
     $acchash{'acc.cond.'.$short.'.0'}=0;      $acchash{'acc.cond.'.$short.'.0'}=0;
     map {  
        if ($_=~/^conditions/) {      # This loop is only interested in conditions and 
   my $expr=$hash{$_};      # parameters in the big hash:
           map {  
              my $sub=$_;      foreach my $key (keys(%hash)) {
              my $orig=$_;  
       $sub=~/\(\((\d+\&(:?\d+\&)*)(?:\d+\&*)+\)(?:\|\(\1(?:\d+\&*)+\))+\)/;   # conditions:
              my $factor=$1;  
              $sub=~s/$factor//g;   if ($key=~/^conditions/) {
              $sub=~s/^\(/\($factor\(/;      my $expr=$hash{$key};
      $sub.=')';  
              $sub=simplify($sub);      # try to find and factor out common sub-expressions
              $orig=~s/(\W)/\\$1/g;      # Any subexpression that is found is simplified, removed from
       $expr=~s/$orig/$sub/;      # the original condition expression and the simplified sub-expression
   } ($expr=~m/(\(\(\d+(?:\&\d+)+\)(?:\|\(\d+(?:\&\d+)+\))+\))/g);      # substituted back in to the epxression..I'm not actually convinced this
           $hash{$_}=$expr;      # factors anything out...but instead maybe simplifies common factors(?)
           unless (defined($captured{$expr})) {  
       $condcounter++;      foreach my $sub ($expr=~m/(\(\([_\.\d]+(?:\&[_\.\d]+)+\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)+\))+\))/g) {
               $captured{$expr}=$condcounter;   my $orig=$sub;
               $acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;  
           }    my ($factor) = ($sub=~/\(\(([_\.\d]+\&(:?[_\.\d]+\&)*)(?:[_\.\d]+\&*)+\)(?:\|\(\1(?:[_\.\d]+\&*)+\))+\)/);
         }   next if (!defined($factor));
     } keys %hash;  
     map {   $sub=~s/\Q$factor\E//g;
  if ($_=~/^ids/) {   $sub=~s/^\(/\($factor\(/;
   map {   $sub.=')';
     my $resid=$_;   $sub=simplify($sub);
             my $uri=$hash{'src_'.$resid};   $expr=~s/\Q$orig\E/$sub/;
             my @uriparts=split(/\//,$uri);      }
             my $urifile=$uriparts[$#uriparts];      $hash{$key}=$expr;
             $#uriparts--;  
             my $uripath=join('/',@uriparts);             # If not yet seen, record in acchash and that we've seen it.
             $uripath=~s/^\/res\///;  
             my $uricond='0';      unless (defined($captured{$expr})) {
             if (defined($hash{'conditions_'.$resid})) {   $condcounter++;
   $uricond=$captured{$hash{'conditions_'.$resid}};   $captured{$expr}=$condcounter;
             }   $acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;
             if (defined($acchash{'acc.res.'.$short.'.'.$uripath})) {      } 
                 if ($acchash{'acc.res.'.$short.'.'.$uripath}=~          # Parameters:
                    /(\&$urifile\:[^\&]*)/) {  
     my $replace=$1;   } elsif ($key=~/^param_(\d+)\.(\d+)/) {
                     $acchash{'acc.res.'.$short.'.'.$uripath}      my $prefix=&Apache::lonnet::encode_symb($hash{'map_id_'.$1},$2,
                      =~s/$replace/$replace\|$uricond/;      $hash{'src_'.$1.'.'.$2});
                 } else {      foreach my $param (split(/\&/,$hash{$key})) {
    $acchash{'acc.res.'.$short.'.'.$uripath}.=   my ($typename,$value)=split(/\=/,$param);
                      $urifile.':'.$uricond.'&';   my ($type,$name)=split(/\:/,$typename);
         }   $parmhash{$prefix.'.'.&unescape($name)}=
             } else {      &unescape($value);
                 $acchash{'acc.res.'.$short.'.'.$uripath}=   $parmhash{$prefix.'.'.&unescape($name).'.type'}=
                  '&'.$urifile.':'.$uricond.'&';      &unescape($type);
             }       }
          } split(/\,/,$hash{$_});   }
       }      }
     } keys %hash;      # This loop only processes id entries in the big hash.
   
       foreach my $key (keys(%hash)) {
    if ($key=~/^ids/) {
       foreach my $resid (split(/\,/,$hash{$key})) {
    my $uri=$hash{'src_'.$resid};
    my ($uripath,$urifile) =
       &Apache::lonnet::split_uri_for_cond($uri);
    if ($uripath) {
       my $uricond='0';
       if (defined($hash{'conditions_'.$resid})) {
    $uricond=$captured{$hash{'conditions_'.$resid}};
       }
       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.'.'.$uripath} =~
    s/\Q$regexp\E/$replace\|$uricond/;
    } else {
       $acchash{'acc.res.'.$short.'.'.$uripath}.=
    $urifile.':'.$uricond.'&';
    }
       } else {
    $acchash{'acc.res.'.$short.'.'.$uripath}=
       '&'.$urifile.':'.$uricond.'&';
       }
    } 
       }
    }
       }
       $acchash{'acc.res.'.$short.'.'}='&:0&';
     my $courseuri=$uri;      my $courseuri=$uri;
     $courseuri=~s/^\/res\///;      $courseuri=~s/^\/res\///;
     &Apache::lonnet::delenv('(acc\.|httpref\.)');      my $regexp = 1;
     &Apache::lonnet::appenv(%acchash,      &Apache::lonnet::delenv('(acc\.|httpref\.)',$regexp);
                             "request.course.id"  => $short,      &Apache::lonnet::appenv(\%acchash);
                             "request.course.fn"  => $fn,  }
                             "request.course.uri" => $courseuri);   
   # ---------------- Selectively delete from randompick maps and hidden url parms
   
   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 my $key (sort(keys(%hash))) {
       if ($key=~/^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 $setcode;
           if (defined($randomizationcode{$rid})) {
               if ($env{'form.CODE'} eq '') {
                   $env{'form.CODE'} = $randomizationcode{$rid};
                   $setcode = 1;
               }
           }
    my $rndseed=&Apache::lonnet::rndseed($id); # use id instead of symb
           if ($setcode) {
               undef($env{'form.CODE'});
               undef($setcode);
           }
    &Apache::lonnet::setup_random_from_rndseed($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[$k]);
                   if ($rescount{$mapid}) {
                       $rescount{$mapid} --;
                   }
                   if ($hash{'is_map_'.$currentrids[$k]}) {
                       if ($mapcount{$mapid}) {
                           $mapcount{$mapid} --;
                       }
                   }
                   $randomoutentry.='&'.
       &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
    $resid,
    $hash{'src_'.$currentrids[$k]}
    ).'&';
               }
           }
       }
   # ------------------------------ take care of explicitly hidden urls or folders
       foreach my $rid (keys(%hiddenurl)) {
    $hash{'randomout_'.$rid}=1;
    my ($mapid,$resid)=split(/\./,$rid);
           if ($rescount{$mapid}) {
               $rescount{$mapid} --;
           }
           if ($hash{'is_map_'.$rid}) {
               if ($mapcount{$mapid}) {
                   $mapcount{$mapid} --;
               }
           }
    $randomoutentry.='&'.
       &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,
    $hash{'src_'.$rid}).'&';
       }
   # --------------------------------------- append randomout entry to environment
       if ($randomoutentry) {
    &Apache::lonnet::appenv({'acc.randomout' => $randomoutentry});
       }
   }
   
   # -------------------------------------- populate big hash with map breadcrumbs
   
   # Create map_breadcrumbs_$pc from map_hierarchy_$pc by omitting intermediate
   # maps not shown in Course Contents table.
   
   sub mapcrumbs {
       foreach my $key (keys(%rescount)) {
           if ($hash{'map_hierarchy_'.$key}) {
               my $skipnext = 0;
               foreach my $id (split(/,/,$hash{'map_hierarchy_'.$key}),$key) {
                   unless ($skipnext) {
                       $hash{'map_breadcrumbs_'.$key} .= "$id,";
                   }
                   unless (($id == 0) || ($id == 1)) {
                       if ((!$rescount{$id}) || ($rescount{$id} == 1 && $mapcount{$id} == 1)) {
                           $skipnext = 1;
                       } else {
                           $skipnext = 0;
                       }
                   }
               }
               $hash{'map_breadcrumbs_'.$key} =~ s/,$//;
           }
       }
 }  }
   
 # ---------------------------------------------------- Read map and all submaps  # ---------------------------------------------------- Read map and all submaps
   
 sub readmap {  sub readmap {
    my $short=shift;      my $short=shift;
    $short=~s/^\///;      $short=~s/^\///;
    my %cenv=&Apache::lonnet::coursedescription($short);  
    my $fn=$cenv{'fn'};      # TODO:  Hidden dependency on current user:
    my $uri;  
    $short=~s/\//\_/g;      my %cenv=&Apache::lonnet::coursedescription($short,{'freshen_cache'=>1}); 
    unless ($uri=$cenv{'url'}) {   
       &Apache::lonnet::logthis("<font color=blue>WARNING: ".      my $fn=$cenv{'fn'};
                        "Could not load course $short.</font>");       my $uri;
       return 'No course data available.';      $short=~s/\//\_/g;
    }      unless ($uri=$cenv{'url'}) { 
    @cond=('true:normal');   &Apache::lonnet::logthis('<font color="blue">WARNING: '.
    unlink($fn.'.db');   "Could not load course $short.</font>"); 
    unlink($fn.'_symb.db');   return ('',&mt('No course data available.'));;
    unlink($fn.'.state');      }
    if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT,0640)) {      @cond=('true:normal');
     %hash=();  
       unless (open(LOCKFILE,">","$fn.db.lock")) {
    # 
    # Most likely a permissions problem on the lockfile or its directory.
    #
           $retfurl = '';
           return ($retfurl,'<br />'.&mt('Map not loaded - Lock file could not be opened when reading map:').' <tt>'.$fn.'</tt>.');
       }
       my $lock=0;
       my $gotstate=0;
       
       # If we can get the lock without delay any files there are idle
       # and from some prior request.  We'll kill them off and regenerate them:
   
       if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) {
    $lock=1; # Remember that we hold the lock.
           &unlink_tmpfiles($fn);
       }
       undef %randompick;
       undef %randompickseed;
       undef %randomorder;
       undef %randomizationcode;
       undef %hiddenurl;
       undef %encurl;
       undef %deeplinkonly;
       undef %rescount;
       undef %mapcount;
       $retfrid='';
     $errtext='';      $errtext='';
       my ($untiedhash,$untiedparmhash,$tiedhash,$tiedparmhash); # More state flags.
   
       # if we got the lock, regenerate course regnerate empty files and tie them.
   
       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,
         $short,
         \%cenv); # TODO: Need to provide requested user@dom
                   unless ($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); # RF: this is what I don't get unless there are other
                            # unlocked places the remainder happens..seems like if we
                                    # just kept the lock here the rest of the code would have
                                    # been much easier? 
       }
       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
    #
    # RF: I'm not seeing the case where the ties/unties can fail in a way
    #     that can be remedied by this.  Since we owned the lock seems
    #     Tie/untie failures are a result of something like a permissions problem instead?
    #
   
    #  In any vent, undo what we did manage to do above first:
    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);
               }
           }
    # Log our failure:
   
    &Apache::lonnet::logthis('<font color="blue">WARNING: '.
    "Could not tie coursemap $fn for $uri.</font>");
           $tiedhash = '';
           $tiedparmhash = '';
    my $i=0;
   
    # Keep on retrying the lock for 90 sec until we succeed.
   
    while($i<90) {
       $i++;
       sleep(1);
       if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) {
   
    # Got the lock, tie the hashes...the assumption in this code is
    # that some other worker thread has created the db files quite recently
    # so no load is needed:
   
                   $lock = 1;
    if (tie(%hash,'GDBM_File',"$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';
   
       # BUG BUG: Side effect!
       # Should conditionalize on something so that we can use this
       # to load maps for courses that are not current?
       #
               &Apache::lonnet::appenv({"request.course.id"  => $short,
                  "request.course.fn"  => $fn,
                "request.course.uri" => $uri,
                                                        "request.course.tied" => time});
                               
               $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 '.$uri.'.</font>');
                   }
               }
           }
       }
       # I think this branch of code is all about what happens if we just did the stuff above, 
       # but found that the  state file did not exist...again if we'd just held the lock
       # would that have made this logic simpler..as generating all the files would be
       # an atomic operation with respect to the lock.
       #
       unless ($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 %randompickseed;
           undef %randomorder;
           undef %randomizationcode;
           undef %hiddenurl;
           undef %encurl;
           undef %deeplinkonly;
           undef %rescount;
           undef %mapcount;
           $errtext='';
           $retfrid='';
    #
    # Once more through the routine of tying and loading and so on.
    #
           if ($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); # TODO: User dependent?
                       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 {
       # Failed to get the immediate lock.
   
               &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); # TODO: User dependent?
       }
   # ------------------------------------------------- Check for critical messages
   
   #  Depends on user must parameterize this as well..or separate as this is:
   #  more part of determining what someone sees on entering a course?
   
       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);
   }
   
   #
   #  This sub is called when the course hash and the param hash have been tied and
   #  their lock file is held.
   #  Parameters:
   #     $uri      -  URI that identifies the course.
   #     $fn       -  The base path/filename of the files that make up the context
   #                  being built.
   #     $short    -  Short course name.
   #     $cenvref  -  Reference to the course environment hash returned by 
   #                  Apache::lonnet::coursedescription
   #
   #  Assumptions:
   #    The globals
   #    %hash, %paramhash are tied to their gdbm files and we hold the lock on them.
   #
   sub build_tmp_hashes {
       my ($uri,$fn,$short,$cenvref) = @_;
       
       unless(ref($cenvref) eq 'HASH') {
           return;
       }
       my %cenv = %{$cenvref};
       my $gotstate = 0;
       %hash=(); # empty the global course and  parameter hashes.
       %parmhash=();
       $errtext=''; # No error messages yet.
     $pc=0;      $pc=0;
     loadmap($uri);      &clear_mapalias_count();
       &processversionfile(%cenv);
   
       # URI Of the map file.
   
       my $furi=&Apache::lonnet::clutter($uri);
       #
       #  the map staring points.
       #
       $hash{'src_0.0'}=&versiontrack($furi);
       $hash{'title_0.0'}=&Apache::lonnet::metadata($uri,'title');
       $hash{'ids_'.$furi}='0.0';
       $hash{'is_map_0.0'}=1;
   
       # Load the map.. note that loadmap may implicitly recurse if the map contains 
       # sub-maps.
   
   
       &loadmap($uri,'0.0',$short);
   
       #  The code below only executes if there is a starting point for the map>
       #  Q/BUG??? If there is no start resource for the map should that be an error?
       #
   
     if (defined($hash{'map_start_'.$uri})) {      if (defined($hash{'map_start_'.$uri})) {
           &Apache::lonnet::appenv({"request.course.id"  => $short,
                                    "request.course.fn"  => $fn,
                                    "request.course.uri" => $uri,
                                    "request.course.tied" => time});
           $env{'request.course.id'}=$short;
         &traceroute('0',$hash{'map_start_'.$uri},'&');          &traceroute('0',$hash{'map_start_'.$uri},'&');
         &accinit($uri,$short,$fn);          &accinit($uri,$short,$fn);
           &hiddenurls();
           &mapcrumbs();
       }
       $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;
           }
     }      }
     unless (untie(%hash)) {  # ---------------------------------------------------------------- Encrypt URLs
       &Apache::lonnet::logthis("<font color=blue>WARNING: ".      foreach my $id (keys(%encurl)) {
                        "Could not untie coursemap $fn for $uri.</font>");   #           $hash{'src_'.$id}=&Apache::lonenc::encrypted($hash{'src_'.$id});
           $hash{'encrypted_'.$id}=1;
     }      }
   # ------------------------------------------------------------ Deep-linked URLs
       foreach my $id (keys(%deeplinkonly)) {
           $hash{'deeplinkonly_'.$id}=$deeplinkonly{$id};
       }
   # ----------------------------------------------- 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;          my $cfh;
      if ($cfh=Apache::File->new(">$fn.state")) {          if (open($cfh,">","$fn.state")) {
         print $cfh join("\n",@cond);              print $cfh join("\n",@cond);
      } else {              $gotstate = 1;
       &Apache::lonnet::logthis("<font color=blue>WARNING: ".          } else {
                        "Could not write statemap $fn for $uri.</font>");               &Apache::lonnet::logthis("<font color=blue>WARNING: ".
      }                                       "Could not write statemap $fn for $uri.</font>");
     }            }
    } else {      }
       &Apache::lonnet::logthis("<font color=blue>WARNING: ".      return $gotstate;
                        "Could not tie coursemap $fn for $uri.</font>");   }
    }  
    &Apache::lonmsg::author_res_msg($ENV{'request.course.uri'},$errtext);  sub unlink_tmpfiles {
    return $errtext;      my ($fn) = @_;
       my $file_dir = dirname($fn);
   
       if ("$file_dir/" eq LONCAPA::tempdir()) {
           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  # ------------------------------------------------------- Evaluate state string
   
 sub evalstate {  sub evalstate {
     my $safeeval = new Safe;      my $fn=$env{'request.course.fn'}.'.state';
     my $fn=$ENV{'request.course.fn'}.'.state';      my $state='';
     my $state='2';  
     if (-e $fn) {      if (-e $fn) {
        my @conditions=();   my @conditions=();
        {   {
         my $fh=Apache::File->new($fn);      open(my $fh,"<",$fn);
         @conditions=<$fh>;      @conditions=<$fh>;
        }                close($fh);
        $safeeval->permit("entereval");   }  
        $safeeval->permit(":base_math");   my $safeeval = new Safe;
        $safeeval->deny(":base_io");   my $safehole = new Safe::Hole;
        $safeeval->share_from('Apache::lonnet',['&varval']);   $safeeval->permit("entereval");
        map {   $safeeval->permit(":base_math");
    my $line=$_;   $safeeval->deny(":base_io");
            chomp($line);   $safehole->wrap(\&Apache::lonnet::EXT,$safeeval,'&EXT');
    my ($condition,$weight)=split(/\:/,$_);   foreach my $line (@conditions) {
            $condition=~s/\[([\w\.]+)\]/\&varval\(\'$1\'\)/g;      chomp($line);
            if ($safeeval->reval($condition)) {      my ($condition,$weight)=split(/\:/,$line);
        if ($weight eq 'force') {      if ($safeeval->reval($condition)) {
    $state.='3';   if ($weight eq 'force') {
                } else {      $state.='3';
                    $state.='2';   } else {
                }      $state.='2';
            } else {   }
                if ($weight eq 'stop') {      } else {
    $state.='0';   if ($weight eq 'stop') {
                } else {      $state.='0';
                    $state.='1';   } else {
                }      $state.='1';
            }   }
        } @conditions;      }
    }
     }      }
     &Apache::lonnet::appenv('user.state.'.$ENV{'request.course.id'} => $state);      &Apache::lonnet::appenv({'user.state.'.$env{'request.course.id'} => $state});
     return $state;      return $state;
 }  }
   
   #  This block seems to have code to manage/detect doubly defined
   #  aliases in maps.
   
   {
       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][_2]in Map [_3]',
        $hash{'title_'.$id},'<br />',
        $hash{'title_'.$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;  1;
 __END__  __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 SUBROUTINES
   
   =over
   
   =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

Removed from v.1.16  
changed lines
  Added in v.1.159


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