Diff for /rat/lonuserstate.pm between versions 1.68 and 1.151

version 1.68, 2003/12/12 16:38:53 version 1.151, 2017/05/08 14:20:32
Line 31  package Apache::lonuserstate; Line 31  package Apache::lonuserstate;
   
 # ------------------------------------------------- modules used by this module  # ------------------------------------------------- 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 Apache::loncommon();
 use GDBM_File;  use GDBM_File;
 use Apache::lonmsg;  use Apache::lonmsg;
 use Safe;  use Safe;
 use Safe::Hole;  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 %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 $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 %randompick; # randomly picked resources
 my %randompickseed; # optional seed for randomly picking 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
   
 # ----------------------------------- Remove version from URL and store in hash  # ----------------------------------- 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 />';
   }
   
   #  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 versiontrack {  sub versiontrack {
     my $uri=shift;      my $uri=shift;
     if ($uri=~/\.(\d+)\.\w+$/) {      if ($uri=~/\.(\d+)\.\w+$/) {
Line 62  sub versiontrack { Line 93  sub versiontrack {
  $uri=~s/\.\d+\.(\w+)$/\.$1/;   $uri=~s/\.\d+\.(\w+)$/\.$1/;
         unless ($hash{'version_'.$uri}) {          unless ($hash{'version_'.$uri}) {
     $hash{'version_'.$uri}=$version;      $hash{'version_'.$uri}=$version;
  }   } elsif ($version!=$hash{'version_'.$uri}) {
               $errtext.=&versionerror($uri,$hash{'version_'.$uri},$version);
           }
     }      }
     return $uri;      return $uri;
 }  }
Line 71  sub versiontrack { Line 104  sub versiontrack {
   
 sub putinversion {  sub putinversion {
     my $uri=shift;      my $uri=shift;
       my $key=$env{'request.course.id'}.'_'.&Apache::lonnet::clutter($uri);
     if ($hash{'version_'.$uri}) {      if ($hash{'version_'.$uri}) {
  my $version=$hash{'version_'.$uri};   my $version=$hash{'version_'.$uri};
  if ($version eq 'mostrecent') { return $uri; }   if ($version eq 'mostrecent') { return $uri; }
Line 79  sub putinversion { Line 113  sub putinversion {
              { return $uri; }               { return $uri; }
  $uri=~s/\.(\w+)$/\.$version\.$1/;   $uri=~s/\.(\w+)$/\.$version\.$1/;
     }      }
       &Apache::lonnet::do_cache_new('courseresversion',$key,&Apache::lonnet::declutter($uri),600);
     return $uri;      return $uri;
 }  }
   
Line 89  sub processversionfile { Line 124  sub processversionfile {
     my %versions=&Apache::lonnet::dump('resourceversions',      my %versions=&Apache::lonnet::dump('resourceversions',
        $cenv{'domain'},         $cenv{'domain'},
        $cenv{'num'});         $cenv{'num'});
     foreach (keys %versions) {      foreach my $ver (keys(%versions)) {
  if ($_=~/^error\:/) { return; }   if ($ver=~/^error\:/) { return; }
  $hash{'version_'.$_}=$versions{$_};   $hash{'version_'.$ver}=$versions{$ver};
     }      }
 }  }
   
 # --------------------------------------------------------- Loads map from disk  # --------------------------------------------------------- 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 {   sub loadmap { 
     my $uri=shift;      my ($uri,$parent_rid,$courseid)=@_;
     if ($hash{'map_pc_'.$uri}) { return OK; }  
       # 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;
   
 # Determine and check filename      # If the parent is of the form n.m hang this map underneath it in the
       # map hierarchy.
   
       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 of the sequence we need to read:
   
     my $fn=&Apache::lonnet::filelocation('',&putinversion($uri));      my $fn=&Apache::lonnet::filelocation('',&putinversion($uri));
   
     my $ispage=($fn=~/\.page$/);      my $ispage=($fn=~/\.page$/);
   
     unless (($fn=~/\.sequence$/) ||      # We can only nest sequences or pages.  Anything else is an illegal nest.
             ($fn=~/\.page$/)) {   
        $errtext.="Invalid map: $fn\n";      unless (($fn=~/\.sequence$/) || $ispage) { 
        return OK;    $errtext.='<br />'.&mt('Invalid map: [_1]',"<tt>$fn</tt>");
    return; 
     }      }
   
       # Read the XML that constitutes the file.
   
     my $instr=&Apache::lonnet::getfile($fn);      my $instr=&Apache::lonnet::getfile($fn);
   
     unless ($instr eq -1) {      if ($instr eq -1) {
           $errtext.= '<br />'
                     .&mt('Map not loaded: The file [_1] does not exist.',
                          "<tt>$fn</tt>");
    return;
       }
   
 # Successfully got file, parse it      # Successfully got file, parse it
   
         my $parser = HTML::TokeParser->new(\$instr);      # parse for parameter processing.
         my $token;      # Note that these are <param... / > tags
       # so we only care about 'S' (tag start) nodes.
   
         my $linkpc=0;  
   
         $fn=~/\.(\w+)$/;      my $parser = HTML::TokeParser->new(\$instr);
       $parser->attr_encoded(1);
   
         $hash{'map_type_'.$lpc}=$1;      # first get all parameters
   
         while ($token = $parser->get_token) {  
     if ($token->[0] eq 'S') {  
                 if ($token->[1] eq 'resource') {  
 # -------------------------------------------------------------------- Resource  
   
                     my $rid=$lpc.'.'.$token->[2]->{'id'};      while (my $token = $parser->get_token) {
    next if ($token->[0] ne 'S');
    if ($token->[1] eq 'param') {
       &parse_param($token,$lpc);
    } 
       }
   
                     $hash{'kind_'.$rid}='res';      # Get set to take another pass through the XML:
                     $hash{'title_'.$rid}=$token->[2]->{'title'};      # for resources and links.
                     my $turi=&versiontrack($token->[2]->{'src'});  
                     if ($token->[2]->{'version'}) {  
  unless ($hash{'version_'.$turi}) {  
     $hash{'version_'.$turi}=$1;  
  }  
     }  
     &Apache::lonnet::do_cache(\%Apache::lonnet::titlecache,  
        &Apache::lonnet::encode_symb($uri,$token->[2]->{'id'},  
     $turi),  
       $token->[2]->{'title'},'title');  
                     unless ($ispage) {  
                         $turi=~/\.(\w+)$/;  
                         my $embstyle=&Apache::loncommon::fileembstyle($1);  
                         if ($token->[2]->{'external'} eq 'true') { # external  
                             $turi=~s/^http\:\/\//\/adm\/wrapper\/ext\//;  
                         } elsif ($turi=~/^\/*uploaded\//) { # uploaded  
     if (($embstyle eq 'img') || ($embstyle eq 'emb')  
                              || ($embstyle eq 'ssi')) {  
                                 $turi='/adm/wrapper'.$turi;  
                             } elsif ($turi!~/\.(sequence|page)$/) {  
  $turi='/adm/coursedocs/showdoc'.$turi;  
                             }  
                         } else { # normal internal resource  
     my $mapdir=$uri;  
     $mapdir=~s/[^\/]+$//;  
     $turi=&Apache::lonnet::hreflocation($mapdir,$turi);  
     if (($embstyle eq 'img') || ($embstyle eq 'emb')) {  
  $turi='/adm/wrapper'.$turi;  
     }  
                         }  
     }  
   
                     if (defined($hash{'ids_'.$turi})) {      $parser = HTML::TokeParser->new(\$instr);
                         $hash{'ids_'.$turi}.=','.$rid;      $parser->attr_encoded(1);
                     } else {  
                         $hash{'ids_'.$turi}=''.$rid;  
                     }  
                  
                     if  
         ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard)$/) {  
  $turi.='?register=1';  
     }  
   
                     $hash{'src_'.$rid}=$turi;      my $linkpc=0;
   
                     if ($token->[2]->{'external'} eq 'true') {      $fn=~/\.(\w+)$/;
                         $hash{'ext_'.$rid}='true:';  
                     } else {      $hash{'map_type_'.$lpc}=$1;
                         $hash{'ext_'.$rid}='false:';  
                     }      my $randomize = ($randomorder{$parent_rid} =~ /^yes$/i);
                     if ($token->[2]->{'type'}) {  
  $hash{'type_'.$rid}=$token->[2]->{'type'};      # Parse the resources, link and condition tags.
                         if ($token->[2]->{'type'} eq 'start') {      # Note that if randomorder or random select is chosen the links and
     $hash{'map_start_'.$uri}="$rid";      # conditions are meaningless but are determined by the randomization.
                         }      # This is handled in the next chunk of code.
                         if ($token->[2]->{'type'} eq 'finish') {  
     $hash{'map_finish_'.$uri}="$rid";      my @map_ids;
                         }      my $codechecked;
                     }  else {      while (my $token = $parser->get_token) {
                         $hash{'type_'.$rid}='normal';   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, $resource_id);
                   unless ($codechecked) {
                       my $startsymb =
                          &Apache::lonnet::encode_symb($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; 
                   }
       }
   
                     if (($turi=~/\.sequence$/) ||         # Link
                         ($turi=~/\.page$/)) {  
                         $hash{'is_map_'.$rid}=1;  
                         &loadmap($turi);  
                     }   
                       
                 } elsif ($token->[1] eq 'condition') {  
 # ------------------------------------------------------------------- Condition  
   
                     my $rid=$lpc.'.'.$token->[2]->{'id'};   } elsif ($token->[1] eq 'link' && !$randomize) {
       &make_link(++$linkpc,$lpc,$token->[2]->{'to'},
          $token->[2]->{'from'},
          $token->[2]->{'condition'}); # note ..condition may be undefined.
   
                     $hash{'kind_'.$rid}='cond';   # condition
                     $cond[$#cond+1]=$token->[2]->{'value'};  
                     $hash{'condid_'.$rid}=$#cond;   } elsif ($token->[1] eq 'condition' && !$randomize) {
                     if ($token->[2]->{'type'}) {      &parse_condition($token,$lpc);
                         $cond[$#cond].=':'.$token->[2]->{'type'};   }
                     }  else {      }
                         $cond[$#cond].=':normal';      undef($codechecked);
                     }  
   
                 } elsif ($token->[1] eq 'link') {  
 # ----------------------------------------------------------------------- Links  
   
                     $linkpc++;      # Handle randomization and random selection
                     my $linkid=$lpc.'.'.$linkpc;  
   
                     my $goesto=$lpc.'.'.$token->[2]->{'to'};      if ($randomize) {
                     my $comesfrom=$lpc.'.'.$token->[2]->{'from'};          my $advanced;
                     my $undercond=0;          if ($env{'request.course.id'}) {
               $advanced = (&Apache::lonnet::allowed('adv') eq 'F');
           } else {
               $env{'request.course.id'} = $courseid;
               $advanced = (&Apache::lonnet::allowed('adv') eq 'F');
               $env{'request.course.id'} = '';
           }
           unless ($advanced) {
               # 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;
                   }
               }
   
                     if ($token->[2]->{'condition'}) {      my $rndseed=&Apache::lonnet::rndseed($seed);
  $undercond=$lpc.'.'.$token->[2]->{'condition'};      &Apache::lonnet::setup_random_from_rndseed($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.  Thes 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);
    } 
       }
   }
   
   
   # -------------------------------------------------------------------- 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?).
   
       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 ($turi=~ m{^/adm/$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 {
    $hash{'ext_'.$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;
    &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';
       }
   }
   
                     $hash{'goesto_'.$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  # ------------------------------------------------------------------- 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 ofr 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;
   
                     my $referid=$lpc.'.'.$token->[2]->{'to'};  
     my $name=$token->[2]->{'name'};  
     my $part;  
     if ($name=~/^parameter_(.*)_/) {  
  $part=$1;  
     } else {  
  $part=0;  
     }  
     $name=~s/^.*_([^_]*)$/$1/;  
                     my $newparam=  
  &Apache::lonnet::escape($token->[2]->{'type'}).':'.  
  &Apache::lonnet::escape($part.'.'.$name).'='.  
  &Apache::lonnet::escape($token->[2]->{'value'});  
                     if (defined($hash{'param_'.$referid})) {  
                         $hash{'param_'.$referid}.='&'.$newparam;  
                     } else {  
                         $hash{'param_'.$referid}=''.$newparam;  
                     }  
                     if ($token->[2]->{'name'} eq 'parameter_mapalias') {  
  $hash{'mapalias_'.$token->[2]->{'value'}}=$referid;  
                     }  
                     if ($token->[2]->{'name'} eq 'parameter_randompick') {  
  $randompick{$referid}=$token->[2]->{'value'};  
                     }  
                     if ($token->[2]->{'name'} eq 'parameter_randompickseed') {  
  $randompick{$referid}=$token->[2]->{'value'};  
                     }  
                 }   
   
             }      if ($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 {      } else {
         $errtext.='Map not loaded: The file does not exist. ';   $hash{'param_'.$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 (($retfurl eq '') && ($hash{'src_'.$rid})   $beenhere.=$rid.'&';  
         && ($hash{'src_'.$rid}!~/\.sequence$/)) {   my ($mapid,$resid)=split(/\./,$rid);
            my ($mapid,$resid)=split(/\./,$rid);   my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,$hash{'src_'.$rid});
            $retfurl=$hash{'src_'.$rid}.   my $hidden=&Apache::lonnet::EXT('resource.0.hiddenresource',$symb);
            (($hash{'src_'.$rid}=~/\?/)?'&':'?').'symb='.  
            &Apache::lonnet::symbclean(   if ($hdnflag || lc($hidden) eq 'yes') {
                            &Apache::lonnet::declutter($hash{'map_id_'.$mapid}).      $hiddenurl{$rid}=1;
                            '___'.$resid.'___'.   }
                            &Apache::lonnet::declutter($hash{'src_'.$rid}));   if (!$hdnflag && lc($hidden) eq 'no') {
        }      delete($hiddenurl{$rid});
        if (defined($hash{'conditions_'.$rid})) {   }
    $hash{'conditions_'.$rid}=simplify(  
    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;
    }
   
    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_'.$rid}})) {
           foreach (split(/\,/,$hash{'to_'.$rid})) {   $sofar=$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 />'.
           }                                     &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, parameters  # ------------------------------ 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)=@_;
     my %acchash=();      my %acchash=();
     my %captured=();      my %captured=();
     my $condcounter=0;      my $condcounter=0;
     $acchash{'acc.cond.'.$short.'.0'}=0;      $acchash{'acc.cond.'.$short.'.0'}=0;
     foreach (keys %hash) {  
        if ($_=~/^conditions/) {      # This loop is only interested in conditions and 
   my $expr=$hash{$_};      # parameters in the big hash:
          foreach ($expr=~m/(\(\(\d+(?:\&\d+)+\)(?:\|\(\d+(?:\&\d+)+\))+\))/g) {  
              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
   }      # 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=~/\(\(([_\.\d]+\&(:?[_\.\d]+\&)*)(?:[_\.\d]+\&*)+\)(?:\|\(\1(?:[_\.\d]+\&*)+\))+\)/);
        } elsif ($_=~/^param_(\d+)\.(\d+)/) {   next if (!defined($factor));
           my $prefix=&Apache::lonnet::declutter($hash{'map_id_'.$1}).  
       '___'.$2.'___'.&Apache::lonnet::declutter($hash{'src_'.$1.'.'.$2});   $sub=~s/\Q$factor\E//g;
           foreach (split(/\&/,$hash{$_})) {   $sub=~s/^\(/\($factor\(/;
      my ($typename,$value)=split(/\=/,$_);   $sub.=')';
              my ($type,$name)=split(/\:/,$typename);   $sub=simplify($sub);
              $parmhash{$prefix.'.'.&Apache::lonnet::unescape($name)}=   $expr=~s/\Q$orig\E/$sub/;
                                    &Apache::lonnet::unescape($value);      }
      $parmhash{$prefix.'.'.&Apache::lonnet::unescape($name).'.type'}=      $hash{$key}=$expr;
                                    &Apache::lonnet::unescape($type);  
           }             # If not yet seen, record in acchash and that we've seen it.
        }  
     }      unless (defined($captured{$expr})) {
     foreach (keys %hash) {   $condcounter++;
  if ($_=~/^ids/) {   $captured{$expr}=$condcounter;
   foreach (split(/\,/,$hash{$_})) {   $acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;
     my $resid=$_;      } 
             my $uri=$hash{'src_'.$resid};          # Parameters:
             $uri=~s/^\/adm\/wrapper//;  
             $uri=&Apache::lonnet::declutter($uri);   } elsif ($key=~/^param_(\d+)\.(\d+)/) {
             my @uriparts=split(/\//,$uri);      my $prefix=&Apache::lonnet::encode_symb($hash{'map_id_'.$1},$2,
             my $urifile=$uriparts[$#uriparts];      $hash{'src_'.$1.'.'.$2});
             $#uriparts--;      foreach my $param (split(/\&/,$hash{$key})) {
             my $uripath=join('/',@uriparts);   my ($typename,$value)=split(/\=/,$param);
            if ($uripath) {   my ($type,$name)=split(/\:/,$typename);
             my $uricond='0';   $parmhash{$prefix.'.'.&unescape($name)}=
             if (defined($hash{'conditions_'.$resid})) {      &unescape($value);
   $uricond=$captured{$hash{'conditions_'.$resid}};   $parmhash{$prefix.'.'.&unescape($name).'.type'}=
             }      &unescape($type);
             if (defined($acchash{'acc.res.'.$short.'.'.$uripath})) {      }
                 if ($acchash{'acc.res.'.$short.'.'.$uripath}=~   }
                    /(\&\Q$urifile\E\:[^\&]*)/) {      }
     my $replace=$1;      # This loop only processes id entries in the big hash.
                     my $regexp=$replace;  
                     $regexp=~s/\|/\\\|/g;      foreach my $key (keys(%hash)) {
                     $acchash{'acc.res.'.$short.'.'.$uripath}   if ($key=~/^ids/) {
                      =~s/$regexp/$replace\|$uricond/;      foreach my $resid (split(/\,/,$hash{$key})) {
                 } else {   my $uri=$hash{'src_'.$resid};
    $acchash{'acc.res.'.$short.'.'.$uripath}.=   my ($uripath,$urifile) =
                      $urifile.':'.$uricond.'&';      &Apache::lonnet::split_uri_for_cond($uri);
         }   if ($uripath) {
             } else {      my $uricond='0';
                 $acchash{'acc.res.'.$short.'.'.$uripath}=      if (defined($hash{'conditions_'.$resid})) {
                  '&'.$urifile.':'.$uricond.'&';   $uricond=$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&';      $acchash{'acc.res.'.$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  # ---------------- Selectively delete from randompick maps and hidden url parms
   
 sub pickrandom {  sub hiddenurls {
     my $randomoutentry='';      my $randomoutentry='';
     foreach my $rid (keys %randompick) {      foreach my $rid (keys(%randompick)) {
         my $rndpick=$randompick{$rid};          my $rndpick=$randompick{$rid};
         my $mpc=$hash{'map_pc_'.$hash{'src_'.$rid}};          my $mpc=$hash{'map_pc_'.$hash{'src_'.$rid}};
 # ------------------------------------------- put existing resources into array  # ------------------------------------------- put existing resources into array
         my @currentrids=();          my @currentrids=();
         foreach (sort(keys(%hash))) {          foreach my $key (sort(keys(%hash))) {
     if ($_=~/^src_($mpc\.\d+)/) {      if ($key=~/^src_($mpc\.\d+)/) {
  if ($hash{'src_'.$1}) { push @currentrids, $1; }   if ($hash{'src_'.$1}) { push @currentrids, $1; }
             }              }
         }          }
Line 475  sub pickrandom { Line 1095  sub pickrandom {
 # -------------------------------- randomly eliminate the ones that should stay  # -------------------------------- randomly eliminate the ones that should stay
  my (undef,$id)=split(/\./,$rid);   my (undef,$id)=split(/\./,$rid);
         if ($randompickseed{$rid}) { $id=$randompickseed{$rid}; }          if ($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   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);   &Apache::lonnet::setup_random_from_rndseed($rndseed);
  my @whichids=&Math::Random::random_permuted_index($#currentrids+1);   my @whichids=&Math::Random::random_permuted_index($#currentrids+1);
         for (my $i=1;$i<=$rndpick;$i++) { $currentrids[$whichids[$i]]=''; }          for (my $i=1;$i<=$rndpick;$i++) { $currentrids[$whichids[$i]]=''; }
Line 486  sub pickrandom { Line 1117  sub pickrandom {
  $hash{'randomout_'.$currentrids[$k]}=1;   $hash{'randomout_'.$currentrids[$k]}=1;
                 my ($mapid,$resid)=split(/\./,$currentrids[$k]);                  my ($mapid,$resid)=split(/\./,$currentrids[$k]);
                 $randomoutentry.='&'.                  $randomoutentry.='&'.
                  &Apache::lonnet::symbclean(      &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
     &Apache::lonnet::declutter($hash{'map_id_'.$mapid}).   $resid,
                     '___'.$resid.'___'.   $hash{'src_'.$currentrids[$k]}
     &Apache::lonnet::declutter($hash{'src_'.$currentrids[$k]})   ).'&';
                  ).'&';  
             }              }
         }          }
     }      }
   # ------------------------------ take care of explicitly hidden urls or folders
       foreach my $rid (keys(%hiddenurl)) {
    $hash{'randomout_'.$rid}=1;
    my ($mapid,$resid)=split(/\./,$rid);
    $randomoutentry.='&'.
       &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,
    $hash{'src_'.$rid}).'&';
       }
   # --------------------------------------- append randomout entry to environment
     if ($randomoutentry) {      if ($randomoutentry) {
  &Apache::lonnet::appenv('acc.randomout' => $randomoutentry);   &Apache::lonnet::appenv({'acc.randomout' => $randomoutentry});
     }      }
 }  }
   
 # ---------------------------------------------------- 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($fn.'.state');      }
    unlink($fn.'parms.db');      @cond=('true:normal');
    undef %randompick;  
    $retfurl='';      unless (open(LOCKFILE,">$fn.db.lock")) {
    if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) &&   # 
        (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640))) {   # Most likely a permissions problem on the lockfile or its directory.
     %hash=();   #
     %parmhash=();          $retfurl = '';
           return ($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 %hiddenurl;
       undef %encurl;
       $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 %hiddenurl;
           undef %encurl;
           $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;
       &clear_mapalias_count();
     &processversionfile(%cenv);      &processversionfile(%cenv);
   
       # URI Of the map file.
   
     my $furi=&Apache::lonnet::clutter($uri);      my $furi=&Apache::lonnet::clutter($uri);
       #
       #  the map staring points.
       #
     $hash{'src_0.0'}=&versiontrack($furi);      $hash{'src_0.0'}=&versiontrack($furi);
     $hash{'title_0.0'}=&Apache::lonnet::metadata($uri,'title');      $hash{'title_0.0'}=&Apache::lonnet::metadata($uri,'title');
     $hash{'ids_'.$furi}='0.0';      $hash{'ids_'.$furi}='0.0';
     $hash{'is_map_0.0'}=1;      $hash{'is_map_0.0'}=1;
     loadmap($uri);  
       # 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);
         &pickrandom();          &hiddenurls();
     }      }
       $errtext .= &get_mapalias_errors();
 # ------------------------------------------------------- Put versions into src  # ------------------------------------------------------- Put versions into src
     foreach (keys %hash) {      foreach my $key (keys(%hash)) {
  if ($_=~/^src\_/) {          if ($key=~/^src_/) {
     $hash{$_}=&putinversion($hash{$_});              $hash{$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)) && (untie(%parmhash))) {  # ---------------------------------------------------------------- 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;
     }      }
   # ----------------------------------------------- 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);  
 # ------------------------------------------------- Check for critical messages  
   
     my @what=&Apache::lonnet::dump('critical',$ENV{'user.domain'},  sub unlink_tmpfiles {
                                               $ENV{'user.name'});      my ($fn) = @_;
     if ($what[0]) {      my $file_dir = dirname($fn);
  if (($what[0] ne 'con_lost') && ($what[0]!~/^error\:/)) {  
     $retfurl='/adm/email?critical=display';      if ("$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 ($retfurl,$errtext);      return;
 }  }
   
 # ------------------------------------------------------- Evaluate state string  # ------------------------------------------------------- Evaluate state string
   
 sub evalstate {  sub evalstate {
       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);
        my $safeeval = new Safe;   }  
        my $safehole = new Safe::Hole;   my $safeeval = new Safe;
        $safeeval->permit("entereval");   my $safehole = new Safe::Hole;
        $safeeval->permit(":base_math");   $safeeval->permit("entereval");
        $safeeval->deny(":base_io");   $safeeval->permit(":base_math");
        $safehole->wrap(\&Apache::lonnet::EXT,$safeeval,'&EXT');   $safeeval->deny(":base_io");
        foreach (@conditions) {   $safehole->wrap(\&Apache::lonnet::EXT,$safeeval,'&EXT');
    my $line=$_;   foreach my $line (@conditions) {
            chomp($line);      chomp($line);
    my ($condition,$weight)=split(/\:/,$_);      my ($condition,$weight)=split(/\:/,$line);
            if ($safeeval->reval($condition)) {      if ($safeeval->reval($condition)) {
        if ($weight eq 'force') {   if ($weight eq 'force') {
    $state.='3';      $state.='3';
                } else {   } else {
                    $state.='2';      $state.='2';
                }   }
            } else {      } else {
                if ($weight eq 'stop') {   if ($weight eq 'stop') {
    $state.='0';      $state.='0';
                } else {   } else {
                    $state.='1';      $state.='1';
                }   }
            }      }
        }   }
     }      }
     &Apache::lonnet::appenv('user.state.'.$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__
   
Line 637  of course for user. Line 1601  of course for user.
 This is part of the LearningOnline Network with CAPA project  This is part of the LearningOnline Network with CAPA project
 described at http://www.lon-capa.org.  described at http://www.lon-capa.org.
   
 =head1 HANDLER SUBROUTINE  =head1 SUBROUTINES
   
 There is no handler subroutine.  
   
 =head1 OTHER 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  =back
   

Removed from v.1.68  
changed lines
  Added in v.1.151


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