File:  [LON-CAPA] / rat / lonuserstate.pm
Revision 1.48: download - view: text, annotated - select for diffs
Thu Dec 12 18:00:24 2002 UTC (21 years, 4 months ago) by www
Branches: MAIN
CVS tags: version_0_6_2, version_0_6, HEAD
Do not jump to a sequence as first resource. This avoids two bugs:
a) part of Bug #963 - courses with /uploaded-sequence as first
   resource now work
b) jumping to a sequence which has a sequence as first resource

    1: # The LearningOnline Network with CAPA
    2: # Construct and maintain state and binary representation of course for user
    3: #
    4: # $Id: lonuserstate.pm,v 1.48 2002/12/12 18:00:24 www Exp $
    5: #
    6: # Copyright Michigan State University Board of Trustees
    7: #
    8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
    9: #
   10: # LON-CAPA is free software; you can redistribute it and/or modify
   11: # it under the terms of the GNU General Public License as published by
   12: # the Free Software Foundation; either version 2 of the License, or
   13: # (at your option) any later version.
   14: #
   15: # LON-CAPA is distributed in the hope that it will be useful,
   16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
   17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   18: # GNU General Public License for more details.
   19: #
   20: # You should have received a copy of the GNU General Public License
   21: # along with LON-CAPA; if not, write to the Free Software
   22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   23: #
   24: # /home/httpd/html/adm/gpl.txt
   25: #
   26: # http://www.lon-capa.org/
   27: #
   28: # (Server for RAT Maps
   29: #
   30: # (Edit Handler for RAT Maps
   31: # (TeX Content Handler
   32: #
   33: # YEAR=2000
   34: # 05/29/00,05/30 Gerd Kortemeyer)
   35: # 7/1 Gerd Kortemeyer)
   36: # 7/1,7/3,7/4,7/7,7/8,7/10 Gerd Kortemeyer)
   37: #
   38: # 7/15,7/17,7/18,8/1,8/2,8/4,8/5,8/21,8/22,8/23,8/30,
   39: # 9/2,9/4,9/29,9/30,10/2,10/11,10/30,10/31,
   40: # 11/1,11/2,11/14,11/16,11/22,12/28,
   41: # YEAR=2001
   42: # 07/05/01,08/30,08/31 Gerd Kortemeyer
   43: # 12/16 Scott Harrison
   44: #
   45: ###
   46: 
   47: package Apache::lonuserstate;
   48: 
   49: # ------------------------------------------------- modules used by this module
   50: use strict;
   51: use Apache::Constants qw(:common :http);
   52: use Apache::File;
   53: use HTML::TokeParser;
   54: use Apache::lonnet();
   55: use Apache::loncommon();
   56: use GDBM_File;
   57: use Apache::lonmsg;
   58: use Safe;
   59: use Safe::Hole;
   60: use Opcode;
   61: 
   62: # ---------------------------------------------------- Globals for this package
   63: 
   64: my $pc;      # Package counter
   65: my %hash;    # The big tied hash
   66: my %parmhash;# The hash with the parameters
   67: my @cond;    # Array with all of the conditions
   68: my $errtext; # variable with all errors
   69: my $retfurl; # variable with the very first URL in the course
   70: my %randompick; # randomly picked resources
   71: my %actualversion; # version of resource as loaded now
   72: my %setversion; # forced version of resource
   73: my %lastversion; # version when CC came in last
   74: my $versionmode; # how versioning is handled in this course
   75: 
   76: # --------------------------------------------------------- Loads map from disk
   77: 
   78: sub loadmap { 
   79:     my $uri=shift;
   80:     if ($hash{'map_pc_'.$uri}) { return OK; }
   81: 
   82:     $pc++;
   83:     my $lpc=$pc;
   84:     $hash{'map_pc_'.$uri}=$lpc;
   85:     $hash{'map_id_'.$lpc}=$uri;
   86: 
   87: # Determine and check filename
   88:     my $fn=&Apache::lonnet::filelocation('',$uri);
   89: 
   90:     my $ispage=($fn=~/\.page$/);
   91: 
   92:     unless (($fn=~/\.sequence$/) ||
   93:             ($fn=~/\.page$/)) { 
   94:        $errtext.="Invalid map: $fn\n";
   95:        return OK; 
   96:     }
   97: 
   98:     my $instr=&Apache::lonnet::getfile($fn);
   99: 
  100:     unless ($instr == -1) {
  101: 
  102: # Successfully got file, parse it
  103: 
  104:         my $parser = HTML::TokeParser->new(\$instr);
  105:         my $token;
  106: 
  107:         my $linkpc=0;
  108: 
  109:         $fn=~/\.(\w+)$/;
  110: 
  111:         $hash{'map_type_'.$lpc}=$1;
  112: 
  113:         while ($token = $parser->get_token) {
  114: 	    if ($token->[0] eq 'S') {
  115:                 if ($token->[1] eq 'resource') {
  116: # -------------------------------------------------------------------- Resource
  117: 
  118:                     my $rid=$lpc.'.'.$token->[2]->{'id'};
  119: 
  120:                     $hash{'kind_'.$rid}='res';
  121:                     $hash{'title_'.$rid}=$token->[2]->{'title'};
  122:                     my $turi=$token->[2]->{'src'};
  123:                     $Apache::lonnet::titlecache{
  124: 		     &Apache::lonnet::symbclean(
  125:                       &Apache::lonnet::declutter($uri).'___'.
  126:                       $token->[2]->{'id'}.'___'.
  127: 		      &Apache::lonnet::declutter($turi))}=
  128:                           $token->[2]->{'title'};
  129:                     unless ($ispage) {
  130:                         $turi=~/\.(\w+)$/;
  131:                         my $embstyle=&Apache::loncommon::fileembstyle($1);
  132:                         if ($token->[2]->{'external'} eq 'true') { # external
  133:                             $turi=~s/^http\:\/\//\/adm\/wrapper\/ext\//;
  134:                         } elsif ($turi=~/^\/*uploaded\//) { # uploaded
  135: 			    if (($embstyle eq 'img') || ($embstyle eq 'emb')
  136:                              || ($embstyle eq 'ssi')) {
  137:                                 $turi='/adm/wrapper'.$turi;
  138:                             } elsif ($turi!~/\.(sequence|page)$/) {
  139: 				$turi='/adm/coursedocs/showdoc'.$turi;
  140:                             }
  141:                         } else { # normal internal resource
  142:                            if (($embstyle eq 'img') || ($embstyle eq 'emb')
  143:              || ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard)$/)) {
  144: 			       $turi='/adm/wrapper'.$turi;
  145:                            }
  146:                         }
  147: 		    }
  148:                     $hash{'src_'.$rid}=$turi;
  149: 
  150:                     if (defined($hash{'ids_'.$turi})) {
  151:                         $hash{'ids_'.$turi}.=','.$rid;
  152:                     } else {
  153:                         $hash{'ids_'.$turi}=''.$rid;
  154:                     }
  155: 
  156:                     if ($token->[2]->{'external'} eq 'true') {
  157:                         $hash{'ext_'.$rid}='true:';
  158:                     } else {
  159:                         $hash{'ext_'.$rid}='false:';
  160:                     }
  161:                     if ($token->[2]->{'type'}) {
  162: 			$hash{'type_'.$rid}=$token->[2]->{'type'};
  163:                         if ($token->[2]->{'type'} eq 'start') {
  164: 			    $hash{'map_start_'.$uri}="$rid";
  165:                         }
  166:                         if ($token->[2]->{'type'} eq 'finish') {
  167: 			    $hash{'map_finish_'.$uri}="$rid";
  168:                         }
  169:                     }  else {
  170:                         $hash{'type_'.$rid}='normal';
  171:                     }
  172: 
  173:                     if (($turi=~/\.sequence$/) ||
  174:                         ($turi=~/\.page$/)) {
  175:                         $hash{'is_map_'.$rid}=1;
  176:                         &loadmap($turi);
  177:                     } 
  178:                     
  179:                 } elsif ($token->[1] eq 'condition') {
  180: # ------------------------------------------------------------------- Condition
  181: 
  182:                     my $rid=$lpc.'.'.$token->[2]->{'id'};
  183: 
  184:                     $hash{'kind_'.$rid}='cond';
  185:                     $cond[$#cond+1]=$token->[2]->{'value'};
  186:                     $hash{'condid_'.$rid}=$#cond;
  187:                     if ($token->[2]->{'type'}) {
  188:                         $cond[$#cond].=':'.$token->[2]->{'type'};
  189:                     }  else {
  190:                         $cond[$#cond].=':normal';
  191:                     }
  192: 
  193:                 } elsif ($token->[1] eq 'link') {
  194: # ----------------------------------------------------------------------- Links
  195: 
  196:                     $linkpc++;
  197:                     my $linkid=$lpc.'.'.$linkpc;
  198: 
  199:                     my $goesto=$lpc.'.'.$token->[2]->{'to'};
  200:                     my $comesfrom=$lpc.'.'.$token->[2]->{'from'};
  201:                     my $undercond=0;
  202: 
  203:                     if ($token->[2]->{'condition'}) {
  204: 			$undercond=$lpc.'.'.$token->[2]->{'condition'};
  205:                     }
  206: 
  207:                     $hash{'goesto_'.$linkid}=$goesto;
  208:                     $hash{'comesfrom_'.$linkid}=$comesfrom;
  209:                     $hash{'undercond_'.$linkid}=$undercond;
  210: 
  211:                     if (defined($hash{'to_'.$comesfrom})) {
  212:                         $hash{'to_'.$comesfrom}.=','.$linkid;
  213:                     } else {
  214:                         $hash{'to_'.$comesfrom}=''.$linkid;
  215:                     }
  216:                     if (defined($hash{'from_'.$goesto})) {
  217:                         $hash{'from_'.$goesto}.=','.$linkid;
  218:                     } else {
  219:                         $hash{'from_'.$goesto}=''.$linkid;
  220:                     }
  221:                 } elsif ($token->[1] eq 'param') {
  222: # ------------------------------------------------------------------- Parameter
  223: 
  224:                     my $referid=$lpc.'.'.$token->[2]->{'to'};
  225:                     my $part=$token->[2]->{'part'};
  226:                     unless ($part) { $part=0; }
  227:                     my $newparam=
  228: 			&Apache::lonnet::escape($token->[2]->{'type'}).':'.
  229: 			&Apache::lonnet::escape($part.'.'.
  230:                          $token->[2]->{'name'}).'='.
  231: 			&Apache::lonnet::escape($token->[2]->{'value'});
  232:                     if (defined($hash{'param_'.$referid})) {
  233:                         $hash{'param_'.$referid}.='&'.$newparam;
  234:                     } else {
  235:                         $hash{'param_'.$referid}=''.$newparam;
  236:                     }
  237:                     if ($token->[2]->{'name'} eq 'parameter_mapalias') {
  238: 			$hash{'mapalias_'.$token->[2]->{'value'}}=$referid;
  239:                     }
  240:                     if ($token->[2]->{'name'} eq 'parameter_randompick') {
  241: 			$randompick{$referid}=$token->[2]->{'value'};
  242:                     }
  243:                 } 
  244: 
  245:             }
  246:         }
  247: 
  248:     } else {
  249:         $errtext.='Map not loaded: The file does not exist. ';
  250:     }
  251: }
  252: 
  253: # --------------------------------------------------------- Simplify expression
  254: 
  255: sub simplify {
  256:    my $expression=shift;
  257: # (8)=8
  258:    $expression=~s/\((\d+)\)/$1/g;
  259: # 8&8=8
  260:    $expression=~s/(\D)(\d+)\&\2(\D)/$1$2$3/g;
  261: # 8|8=8
  262:    $expression=~s/(\D)(\d+)\|\2(\D)/$1$2$3/g;
  263: # (5&3)&4=5&3&4
  264:    $expression=~s/\((\d+)((?:\&\d+)+)\)\&(\d+\D)/$1$2\&$3/g;
  265: # (((5&3)|(4&6)))=((5&3)|(4&6))
  266:    $expression=~
  267:        s/\((\(\(\d+(?:\&\d+)*\)(?:\|\(\d+(?:\&\d+)*\))+\))\)/$1/g;
  268: # ((5&3)|(4&6))|(1&2)=(5&3)|(4&6)|(1&2)
  269:    $expression=~
  270:        s/\((\(\d+(?:\&\d+)*\))((?:\|\(\d+(?:\&\d+)*\))+)\)\|(\(\d+(?:\&\d+)*\))/\($1$2\|$3\)/g;
  271:    return $expression;
  272: }
  273: 
  274: # -------------------------------------------------------- Build condition hash
  275: 
  276: sub traceroute {
  277:     my ($sofar,$rid,$beenhere)=@_;
  278:     $sofar=simplify($sofar);
  279:     unless ($beenhere=~/\&$rid\&/) {
  280:        $beenhere.=$rid.'&';  
  281:        if (($retfurl eq '') && ($hash{'src_'.$rid})
  282:         && ($hash{'src_'.$rid}!~/\.sequence$/)) {
  283:            my ($mapid,$resid)=split(/\./,$rid);
  284:            $retfurl=$hash{'src_'.$rid}.
  285:            (($hash{'src_'.$rid}=~/\?/)?'&':'?').'symb='.
  286:            &Apache::lonnet::symbclean(
  287:                            &Apache::lonnet::declutter($hash{'map_id_'.$mapid}).
  288:                            '___'.$resid.'___'.
  289:                            &Apache::lonnet::declutter($hash{'src_'.$rid}));
  290:        }
  291:        if (defined($hash{'conditions_'.$rid})) {
  292: 	   $hash{'conditions_'.$rid}=simplify(
  293:            '('.$hash{'conditions_'.$rid}.')|('.$sofar.')');
  294:        } else {
  295:            $hash{'conditions_'.$rid}=$sofar;
  296:        }
  297:        if (defined($hash{'is_map_'.$rid})) {
  298:            if (defined($hash{'map_start_'.$hash{'src_'.$rid}})) {
  299: 	       &traceroute($sofar,$hash{'map_start_'.$hash{'src_'.$rid}},'&');
  300:                if (defined($hash{'map_finish_'.$hash{'src_'.$rid}})) {
  301: 		   $sofar=
  302:                   $hash{'conditions_'.$hash{'map_finish_'.$hash{'src_'.$rid}}};
  303:                }
  304:            }
  305:        }
  306:        if (defined($hash{'to_'.$rid})) {
  307:           foreach (split(/\,/,$hash{'to_'.$rid})) {
  308: 		my $further=$sofar;
  309:                 if ($hash{'undercond_'.$_}) {
  310: 		   if (defined($hash{'condid_'.$hash{'undercond_'.$_}})) {
  311:   		       $further=simplify('('.$further.')&('.
  312:                               $hash{'condid_'.$hash{'undercond_'.$_}}.')');
  313: 		   } else {
  314:                        $errtext.='Undefined condition ID: '
  315:                                  .$hash{'undercond_'.$_}.'. ';
  316:                    }
  317:                 }
  318:                 &traceroute($further,$hash{'goesto_'.$_},$beenhere);
  319:           }
  320:        }
  321:     }
  322: }
  323: 
  324: # ------------------------------ Cascading conditions, quick access, parameters
  325: 
  326: sub accinit {
  327:     my ($uri,$short,$fn)=@_;
  328:     my %acchash=();
  329:     my %captured=();
  330:     my $condcounter=0;
  331:     $acchash{'acc.cond.'.$short.'.0'}=0;
  332:     foreach (keys %hash) {
  333:        if ($_=~/^conditions/) {
  334: 	  my $expr=$hash{$_};
  335:          foreach ($expr=~m/(\(\(\d+(?:\&\d+)+\)(?:\|\(\d+(?:\&\d+)+\))+\))/g) {
  336:              my $sub=$_;
  337:              my $orig=$_;
  338:       $sub=~/\(\((\d+\&(:?\d+\&)*)(?:\d+\&*)+\)(?:\|\(\1(?:\d+\&*)+\))+\)/;
  339:              my $factor=$1;
  340:              $sub=~s/$factor//g;
  341:              $sub=~s/^\(/\($factor\(/;
  342: 	     $sub.=')';
  343:              $sub=simplify($sub);
  344:              $orig=~s/(\W)/\\$1/g;
  345:  	     $expr=~s/$orig/$sub/;
  346: 	  }
  347:           $hash{$_}=$expr;
  348:           unless (defined($captured{$expr})) {
  349: 	      $condcounter++;
  350:               $captured{$expr}=$condcounter;
  351:               $acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;
  352:           } 
  353:        } elsif ($_=~/^param_(\d+)\.(\d+)/) {
  354:           my $prefix=&Apache::lonnet::declutter($hash{'map_id_'.$1}).
  355:       '___'.$2.'___'.&Apache::lonnet::declutter($hash{'src_'.$1.'.'.$2});
  356:           foreach (split(/\&/,$hash{$_})) {
  357: 	     my ($typename,$value)=split(/\=/,$_);
  358:              my ($type,$name)=split(/\:/,$typename);
  359:              $parmhash{$prefix.'.'.&Apache::lonnet::unescape($name)}=
  360:                                    &Apache::lonnet::unescape($value);
  361: 	     $parmhash{$prefix.'.'.&Apache::lonnet::unescape($name).'.type'}=
  362:                                    &Apache::lonnet::unescape($type);
  363:           }
  364:        }
  365:     }
  366:     foreach (keys %hash) {
  367: 	if ($_=~/^ids/) {
  368: 	  foreach (split(/\,/,$hash{$_})) {
  369: 	    my $resid=$_;
  370:             my $uri=$hash{'src_'.$resid};
  371:             $uri=~s/^\/adm\/wrapper//;
  372:             my @uriparts=split(/\//,$uri);
  373:             my $urifile=$uriparts[$#uriparts];
  374:             $#uriparts--;
  375:             my $uripath=join('/',@uriparts);
  376:             $uripath=~s/^\/res\///;
  377:            if ($uripath) {
  378:             my $uricond='0';
  379:             if (defined($hash{'conditions_'.$resid})) {
  380:  		$uricond=$captured{$hash{'conditions_'.$resid}};
  381:             }
  382:             if (defined($acchash{'acc.res.'.$short.'.'.$uripath})) {
  383:                 if ($acchash{'acc.res.'.$short.'.'.$uripath}=~
  384:                    /(\&$urifile\:[^\&]*)/) {
  385: 		    my $replace=$1;
  386:                     my $regexp=$replace;
  387:                     $regexp=~s/\|/\\\|/g;
  388:                     $acchash{'acc.res.'.$short.'.'.$uripath}
  389:                      =~s/$regexp/$replace\|$uricond/;
  390:                 } else {
  391: 		   $acchash{'acc.res.'.$short.'.'.$uripath}.=
  392:                      $urifile.':'.$uricond.'&';
  393: 	        }
  394:             } else {
  395:                 $acchash{'acc.res.'.$short.'.'.$uripath}=
  396:                  '&'.$urifile.':'.$uricond.'&';
  397:             }
  398:            } 
  399:          }
  400:       }
  401:     }
  402:     $acchash{'acc.res.'.$short.'.'}='&:0&';
  403:     my $courseuri=$uri;
  404:     $courseuri=~s/^\/res\///;
  405:     &Apache::lonnet::delenv('(acc\.|httpref\.)');
  406:     &Apache::lonnet::appenv(%acchash,
  407:                             "request.course.id"  => $short,
  408:                             "request.course.fn"  => $fn,
  409:                             "request.course.uri" => $courseuri); 
  410: }
  411: 
  412: # ------------------------------------- Selectively delete from randompick maps
  413: 
  414: sub pickrandom {
  415:     my $randomoutentry='';
  416:     foreach my $rid (keys %randompick) {
  417:         my $rndpick=$randompick{$rid};
  418:         my $mpc=$hash{'map_pc_'.$hash{'src_'.$rid}};
  419: # ------------------------------------------- put existing resources into array
  420:         my @currentrids=();
  421:         foreach (keys %hash) {
  422: 	    if ($_=~/^src_($mpc\.\d+)/) {
  423: 		if ($hash{'src_'.$1}) { push @currentrids, $1; }
  424:             }
  425:         }
  426:         next if ($#currentrids<$rndpick);
  427: # -------------------------------- randomly eliminate the ones that should stay
  428: 	srand(&Apache::lonnet::rndseed($rid)); # use rid instead of symb
  429:         for (my $i=1;$i<=$rndpick;$i++) {
  430:             while (1) {
  431: 		my $randomidx=int(rand($#currentrids+1));
  432:                 if ($currentrids[$randomidx]) {
  433: 		    $currentrids[$randomidx]='';
  434:                     last;
  435:                 }
  436:             }
  437:         }
  438: # -------------------------------------------------------- delete the leftovers
  439:         for (my $k=0; $k<=$#currentrids; $k++) {
  440:             if ($currentrids[$k]) {
  441: 		$hash{'randomout_'.$currentrids[$k]}=1;
  442:                 my ($mapid,$resid)=split(/\./,$currentrids[$k]);
  443:                 $randomoutentry.='&'.
  444:                  &Apache::lonnet::symbclean(
  445: 		    &Apache::lonnet::declutter($hash{'map_id_'.$mapid}).
  446:                     '___'.$resid.'___'.
  447: 		    &Apache::lonnet::declutter($hash{'src_'.$currentrids[$k]})
  448:                  ).'&';
  449:             }
  450:         }
  451:     }
  452:     if ($randomoutentry) {
  453: 	&Apache::lonnet::appenv('acc.randomout' => $randomoutentry);
  454:     }
  455: }
  456: 
  457: # ---------------------------------------------------- Read map and all submaps
  458: 
  459: sub readmap {
  460:    my $short=shift;
  461:    $short=~s/^\///;
  462:    my %cenv=&Apache::lonnet::coursedescription($short);
  463:    my $fn=$cenv{'fn'};
  464:    my $uri;
  465:    $short=~s/\//\_/g;
  466:    unless ($uri=$cenv{'url'}) { 
  467:       &Apache::lonnet::logthis("<font color=blue>WARNING: ".
  468:                        "Could not load course $short.</font>"); 
  469:       return 'No course data available.';
  470:    }
  471:    @cond=('true:normal');
  472:    unlink($fn.'.db');
  473:    unlink($fn.'_symb.db');
  474:    unlink($fn.'.state');
  475:    unlink($fn.'parms.db');
  476:    undef %randompick;
  477:    $retfurl='';
  478:    if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) &&
  479:        (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640))) {
  480:     %hash=();
  481:     %parmhash=();
  482:     $errtext='';
  483:     $pc=0;
  484:     my $furi=&Apache::lonnet::clutter($uri);
  485:     $hash{'src_0.0'}=$furi;
  486:     $hash{'title_0.0'}=&Apache::lonnet::metadata($uri,'title');
  487:     $hash{'ids_'.$furi}='0.0';
  488:     $hash{'is_map_0.0'}=1;
  489:     loadmap($uri);
  490:     if (defined($hash{'map_start_'.$uri})) {
  491:         &traceroute('0',$hash{'map_start_'.$uri},'&');
  492:         &accinit($uri,$short,$fn);
  493:         &pickrandom();
  494:     }
  495: # ------------------------------------------------------------ Version tracking
  496: #    if (&Apache::lonnet::allowed('srm',$ENV{'request.course.id'})) {
  497: #	&Apache::lonnet::logthis('Will be version tracking');
  498: #    }
  499:     unless ((untie(%hash)) && (untie(%parmhash))) {
  500:       &Apache::lonnet::logthis("<font color=blue>WARNING: ".
  501:                        "Could not untie coursemap $fn for $uri.</font>"); 
  502:     }
  503:     {
  504:      my $cfh;
  505:      if ($cfh=Apache::File->new(">$fn.state")) {
  506:         print $cfh join("\n",@cond);
  507:      } else {
  508:       &Apache::lonnet::logthis("<font color=blue>WARNING: ".
  509:                        "Could not write statemap $fn for $uri.</font>"); 
  510:      }
  511:     }  
  512:    } else {
  513:       &Apache::lonnet::logthis("<font color=blue>WARNING: ".
  514:                        "Could not tie coursemap $fn for $uri.</font>"); 
  515:    }
  516:    &Apache::lonmsg::author_res_msg($ENV{'request.course.uri'},$errtext);
  517: # ------------------------------------------------- Check for critical messages
  518: 
  519:     my @what=&Apache::lonnet::dump('critical',$ENV{'user.domain'},
  520:                                               $ENV{'user.name'});
  521:     if ($what[0]) {
  522: 	if (($what[0] ne 'con_lost') && ($what[0]!~/^error\:/)) {
  523: 	    $retfurl='/adm/email?critical=display';
  524:         }
  525:     }
  526:    return ($retfurl,$errtext);
  527: }
  528: 
  529: # ------------------------------------------------------- Evaluate state string
  530: 
  531: sub evalstate {
  532: 
  533:     my $fn=$ENV{'request.course.fn'}.'.state';
  534:     my $state='2';
  535:     if (-e $fn) {
  536:        my @conditions=();
  537:        {
  538:         my $fh=Apache::File->new($fn);
  539:         @conditions=<$fh>;
  540:        }  
  541:        my $safeeval = new Safe;
  542:        my $safehole = new Safe::Hole;
  543:        $safeeval->permit("entereval");
  544:        $safeeval->permit(":base_math");
  545:        $safeeval->deny(":base_io");
  546:        $safehole->wrap(\&Apache::lonnet::EXT,$safeeval,'&EXT');
  547:        foreach (@conditions) {
  548: 	   my $line=$_;
  549:            chomp($line);
  550: 	   my ($condition,$weight)=split(/\:/,$_);
  551:            if ($safeeval->reval($condition)) {
  552: 	       if ($weight eq 'force') {
  553: 		   $state.='3';
  554:                } else {
  555:                    $state.='2';
  556:                }
  557:            } else {
  558:                if ($weight eq 'stop') {
  559: 		   $state.='0';
  560:                } else {
  561:                    $state.='1';
  562:                }
  563:            }
  564:        }
  565:     }
  566:     &Apache::lonnet::appenv('user.state.'.$ENV{'request.course.id'} => $state);
  567:     return $state;
  568: }
  569: 
  570: 1;
  571: __END__
  572: 
  573: =head1 NAME
  574: 
  575: Apache::lonuserstate - Construct and maintain state and binary representation
  576: of course for user
  577: 
  578: =head1 SYNOPSIS
  579: 
  580: Invoked by lonroles.pm.
  581: 
  582: &Apache::lonuserstate::readmap($cdom.'/'.$cnum);
  583: 
  584: =head1 INTRODUCTION
  585: 
  586: This module constructs and maintains state and binary representation
  587: of course for user.
  588: 
  589: This is part of the LearningOnline Network with CAPA project
  590: described at http://www.lon-capa.org.
  591: 
  592: =head1 HANDLER SUBROUTINE
  593: 
  594: There is no handler subroutine.
  595: 
  596: =head1 OTHER SUBROUTINES
  597: 
  598: =over 4
  599: 
  600: =item *
  601: 
  602: loadmap() : Loads map from disk
  603: 
  604: =item *
  605: 
  606: simplify() : Simplify expression
  607: 
  608: =item *
  609: 
  610: traceroute() : Build condition hash
  611: 
  612: =item *
  613: 
  614: accinit() : Cascading conditions, quick access, parameters
  615: 
  616: =item *
  617: 
  618: readmap() : Read map and all submaps
  619: 
  620: =item *
  621: 
  622: evalstate() : Evaluate state string
  623: 
  624: =back
  625: 
  626: =cut

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