Return to lonuserstate.pm CVS log

Up to [LON-CAPA] / rat

grppg replaces with smppg for group homepages.  Context determined from course domain and course number in URL.

# The LearningOnline Network with CAPA
# Construct and maintain state and binary representation of course for user
#
# $Id: lonuserstate.pm,v 1.118 2006/07/07 22:01:25 raeburn Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
###

package Apache::lonuserstate;

# ------------------------------------------------- modules used by this module
use strict;
use HTML::TokeParser;
use Apache::lonnet;
use Apache::lonlocal;
use Apache::loncommon();
use GDBM_File;
use Apache::lonmsg;
use Safe;
use Safe::Hole;
use Opcode;
use Apache::lonenc;
use Fcntl qw(:flock);
use LONCAPA;
 

# ---------------------------------------------------- Globals for this package

my $pc;      # Package counter
my %hash;    # The big tied hash
my %parmhash;# The hash with the parameters
my @cond;    # Array with all of the conditions
my $errtext; # variable with all errors
my $retfrid; # variable with the very first RID in the course
my $retfurl; # first URL
my %randompick; # randomly picked resources
my %randompickseed; # optional seed for randomly picking resources
my %encurl; # URLs in this folder are supposed to be encrypted
my %hiddenurl; # this URL (or complete folder) is supposed to be hidden

# ----------------------------------- Remove version from URL and store in hash

sub versiontrack {
    my $uri=shift;
    if ($uri=~/\.(\d+)\.\w+$/) {
	my $version=$1;
	$uri=~s/\.\d+\.(\w+)$/\.$1/;
        unless ($hash{'version_'.$uri}) {
	    $hash{'version_'.$uri}=$version;
	}
    }
    return $uri;
}

# -------------------------------------------------------------- Put in version

sub putinversion {
    my $uri=shift;
    my $key=$env{'request.course.id'}.'_'.&Apache::lonnet::clutter($uri);
    if ($hash{'version_'.$uri}) {
	my $version=$hash{'version_'.$uri};
	if ($version eq 'mostrecent') { return $uri; }
	if ($version eq &Apache::lonnet::getversion(
			&Apache::lonnet::filelocation('',$uri))) 
	             { return $uri; }
	$uri=~s/\.(\w+)$/\.$version\.$1/;
    }
    &Apache::lonnet::do_cache_new('courseresversion',$key,&Apache::lonnet::declutter($uri),600);
    return $uri;
}

# ----------------------------------------- Processing versions file for course

sub processversionfile {
    my %cenv=@_;
    my %versions=&Apache::lonnet::dump('resourceversions',
				       $cenv{'domain'},
				       $cenv{'num'});
    foreach my $ver (keys(%versions)) {
	if ($ver=~/^error\:/) { return; }
	$hash{'version_'.$ver}=$versions{$ver};
    }
}

# --------------------------------------------------------- Loads map from disk

sub loadmap { 
    my $uri=shift;
    if ($hash{'map_pc_'.$uri}) { 
	$errtext.=&mt('<br />Multiple use of sequence/page <tt>[_1]</tt>! The course will not function properly.',$uri);
	return; 
    }
    $pc++;
    my $lpc=$pc;
    $hash{'map_pc_'.$uri}=$lpc;
    $hash{'map_id_'.$lpc}=$uri;

# Determine and check filename
    my $fn=&Apache::lonnet::filelocation('',&putinversion($uri));

    my $ispage=($fn=~/\.page$/);

    unless (($fn=~/\.sequence$/) ||
            ($fn=~/\.page$/)) { 
	$errtext.=&mt("<br />Invalid map: <tt>[_1]</tt>",$fn);
	return; 
    }

    my $instr=&Apache::lonnet::getfile($fn);

    unless ($instr eq -1) {

# Successfully got file, parse it

        my $parser = HTML::TokeParser->new(\$instr);
	$parser->attr_encoded(1);
        my $token;

        my $linkpc=0;

        $fn=~/\.(\w+)$/;

        $hash{'map_type_'.$lpc}=$1;

        while ($token = $parser->get_token) {
	    if ($token->[0] eq 'S') {
                if ($token->[1] eq 'resource') {
# -------------------------------------------------------------------- Resource
                    if ($token->[2]->{'type'} eq 'zombie') { next; }
                    my $rid=$lpc.'.'.$token->[2]->{'id'};

                    $hash{'kind_'.$rid}='res';
                    $hash{'title_'.$rid}=$token->[2]->{'title'};
                    my $turi=&versiontrack($token->[2]->{'src'});
                    if ($token->[2]->{'version'}) {
			unless ($hash{'version_'.$turi}) {
			    $hash{'version_'.$turi}=$1;
			}
		    }
		    my $title=$token->[2]->{'title'};
		    $title=~s/\&colon\;/\:/gs;
#		    my $symb=&Apache::lonnet::encode_symb($uri,
#							  $token->[2]->{'id'},
#							  $turi);
#		    &Apache::lonnet::do_cache_new('title',$symb,$title);
                    unless ($ispage) {
                        $turi=~/\.(\w+)$/;
                        my $embstyle=&Apache::loncommon::fileembstyle($1);
                        if ($token->[2]->{'external'} eq 'true') { # external
                            $turi=~s/^http\:\/\//\/adm\/wrapper\/ext\//;
                        } elsif ($turi=~/^\/*uploaded\//) { # uploaded
			    if (($embstyle eq 'img') 
				|| ($embstyle eq 'emb')
				|| ($embstyle eq 'wrp')) {
                                $turi='/adm/wrapper'.$turi;
			    } elsif ($embstyle eq 'ssi') {
				#do nothing with these
			    } elsif ($turi!~/\.(sequence|page)$/) {
				$turi='/adm/coursedocs/showdoc'.$turi;
                            }
                        } elsif ($turi=~/\S/) { # normal non-empty internal resource
			    my $mapdir=$uri;
			    $mapdir=~s/[^\/]+$//;
			    $turi=&Apache::lonnet::hreflocation($mapdir,$turi);
			    if (($embstyle eq 'img') 
				|| ($embstyle eq 'emb')
				|| ($embstyle eq 'wrp')) {
				$turi='/adm/wrapper'.$turi;
			    }
                        }
		    }
# Store reverse lookup, remove query string
		    my $idsuri=$turi;
		    $idsuri=~s/\?.+$//;
                    if (defined($hash{'ids_'.$idsuri})) {
                        $hash{'ids_'.$idsuri}.=','.$rid;
                    } else {
                        $hash{'ids_'.$idsuri}=''.$rid;
                    }
               
                    if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard)$/) {
			$turi.='?register=1';
		    }

                    $hash{'src_'.$rid}=$turi;

                    if ($token->[2]->{'external'} eq 'true') {
                        $hash{'ext_'.$rid}='true:';
                    } else {
                        $hash{'ext_'.$rid}='false:';
                    }
                    if ($token->[2]->{'type'}) {
			$hash{'type_'.$rid}=$token->[2]->{'type'};
                        if ($token->[2]->{'type'} eq 'start') {
			    $hash{'map_start_'.$uri}="$rid";
                        }
                        if ($token->[2]->{'type'} eq 'finish') {
			    $hash{'map_finish_'.$uri}="$rid";
                        }
                    }  else {
                        $hash{'type_'.$rid}='normal';
                    }

                    if (($turi=~/\.sequence$/) ||
                        ($turi=~/\.page$/)) {
                        $hash{'is_map_'.$rid}=1;
                        &loadmap($turi);
                    } 
                    
                } elsif ($token->[1] eq 'condition') {
# ------------------------------------------------------------------- Condition

                    my $rid=$lpc.'.'.$token->[2]->{'id'};

                    $hash{'kind_'.$rid}='cond';
                    $cond[$#cond+1]=$token->[2]->{'value'};
                    $hash{'condid_'.$rid}=$#cond;
                    if ($token->[2]->{'type'}) {
                        $cond[$#cond].=':'.$token->[2]->{'type'};
                    }  else {
                        $cond[$#cond].=':normal';
                    }

                } elsif ($token->[1] eq 'link') {
# ----------------------------------------------------------------------- Links

                    $linkpc++;
                    my $linkid=$lpc.'.'.$linkpc;

                    my $goesto=$lpc.'.'.$token->[2]->{'to'};
                    my $comesfrom=$lpc.'.'.$token->[2]->{'from'};
                    my $undercond=0;

                    if ($token->[2]->{'condition'}) {
			$undercond=$lpc.'.'.$token->[2]->{'condition'};
                    }

                    $hash{'goesto_'.$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

                    my $referid=$lpc.'.'.$token->[2]->{'to'};
		    my $name=$token->[2]->{'name'};
		    my $part;
		    if ($name=~/^parameter_(.*)_/) {
			$part=$1;
		    } else {
			$part=0;
		    }
		    $name=~s/^.*_([^_]*)$/$1/;
                    my $newparam=
			&escape($token->[2]->{'type'}).':'.
			&escape($part.'.'.$name).'='.
			&escape($token->[2]->{'value'});
                    if (defined($hash{'param_'.$referid})) {
                        $hash{'param_'.$referid}.='&'.$newparam;
                    } else {
                        $hash{'param_'.$referid}=''.$newparam;
                    }
                    if ($token->[2]->{'name'}=~/^parameter_(0_)*mapalias$/) {
			$hash{'mapalias_'.$token->[2]->{'value'}}=$referid;
                    }
                    if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) {
			$randompick{$referid}=$token->[2]->{'value'};
                    }
                    if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) {
			$randompick{$referid}=$token->[2]->{'value'};
                    }
                    if ($token->[2]->{'name'}=~/^parameter_(0_)*encrypturl$/) {
			if ($token->[2]->{'value'}=~/^yes$/i) {
			    $encurl{$referid}=1;
			}
                    }
                    if ($token->[2]->{'name'}=~/^parameter_(0_)*hiddenresource$/) {
			if ($token->[2]->{'value'}=~/^yes$/i) {
			    $hiddenurl{$referid}=1;
			}
                    }
                } 
		
            }
        }

    } else {
        $errtext.=&mt('<br />Map not loaded: The file <tt>[_1]</tt> does not exist.',$fn);
    }
}

# --------------------------------------------------------- Simplify expression

sub simplify {
    my $expression=shift;
# (0&1) = 1
    $expression=~s/\(0\&([_\.\d]+)\)/$1/g;
# (8)=8
    $expression=~s/\(([_\.\d]+)\)/$1/g;
# 8&8=8
    $expression=~s/([^_\.\d])([_\.\d]+)\&\2([^_\.\d])/$1$2$3/g;
# 8|8=8
    $expression=~s/([^_\.\d])([_\.\d]+)\|\2([^_\.\d])/$1$2$3/g;
# (5&3)&4=5&3&4
    $expression=~s/\(([_\.\d]+)((?:\&[_\.\d]+)+)\)\&([_\.\d]+[^_\.\d])/$1$2\&$3/g;
# (((5&3)|(4&6)))=((5&3)|(4&6))
    $expression=~
	s/\((\(\([_\.\d]+(?:\&[_\.\d]+)*\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+\))\)/$1/g;
# ((5&3)|(4&6))|(1&2)=(5&3)|(4&6)|(1&2)
    $expression=~
	s/\((\([_\.\d]+(?:\&[_\.\d]+)*\))((?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+)\)\|(\([_\.\d]+(?:\&[_\.\d]+)*\))/\($1$2\|$3\)/g;
    return $expression;
}

# -------------------------------------------------------- Build condition hash

sub traceroute {
    my ($sofar,$rid,$beenhere,$encflag,$hdnflag)=@_;
    my $newsofar=$sofar=simplify($sofar);
    unless ($beenhere=~/\&$rid\&/) {
	$beenhere.=$rid.'&';  
	my ($mapid,$resid)=split(/\./,$rid);
	my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,$hash{'src_'.$rid});
	my $hidden=&Apache::lonnet::EXT('resource.0.hiddenresource',$symb);

	if ($hdnflag || lc($hidden) eq 'yes') {
	    $hiddenurl{$rid}=1;
	}
	if (!$hdnflag && lc($hidden) eq 'no') {
	    delete($hiddenurl{$rid});
	}

	my $encrypt=&Apache::lonnet::EXT('resource.0.encrypturl',$symb);
	if ($encflag || lc($encrypt) eq 'yes') { $encurl{$rid}=1; }
	if (($retfrid eq '') && ($hash{'src_'.$rid})
	    && ($hash{'src_'.$rid}!~/\.sequence$/)) {
	    $retfrid=$rid;
	}
	if (defined($hash{'conditions_'.$rid})) {
	    $hash{'conditions_'.$rid}=simplify(
           '('.$hash{'conditions_'.$rid}.')|('.$sofar.')');
	} else {
	    $hash{'conditions_'.$rid}=$sofar;
	}

	# if the expression is just the 0th condition keep it
	# otherwise leave a pointer to this condition expression
	$newsofar = ($sofar eq '0') ? $sofar : '_'.$rid;

	if (defined($hash{'is_map_'.$rid})) {
	    if (defined($hash{'map_start_'.$hash{'src_'.$rid}})) {
		$sofar=$newsofar=
		    &traceroute($sofar,
				$hash{'map_start_'.$hash{'src_'.$rid}},'&',
				$encflag || $encurl{$rid},
				$hdnflag || $hiddenurl{$rid});
	    }
	}
	if (defined($hash{'to_'.$rid})) {
	    foreach my $id (split(/\,/,$hash{'to_'.$rid})) {
		my $further=$sofar;
                if ($hash{'undercond_'.$id}) {
		    if (defined($hash{'condid_'.$hash{'undercond_'.$id}})) {
			$further=simplify('('.'_'.$rid.')&('.
					  $hash{'condid_'.$hash{'undercond_'.$id}}.')');
		    } else {
			$errtext.=&mt('<br />Undefined condition ID: [_1]',$hash{'undercond_'.$id});
		    }
                }
                $newsofar=&traceroute($further,$hash{'goesto_'.$id},$beenhere,
				      $encflag,$hdnflag);
	    }
	}
    }
    return $newsofar;
}

# ------------------------------ Cascading conditions, quick access, parameters

sub accinit {
    my ($uri,$short,$fn)=@_;
    my %acchash=();
    my %captured=();
    my $condcounter=0;
    $acchash{'acc.cond.'.$short.'.0'}=0;
    foreach my $key (keys(%hash)) {
	if ($key=~/^conditions/) {
	    my $expr=$hash{$key};
	    # try to find and factor out common sub-expressions
	    foreach my $sub ($expr=~m/(\(\([_\.\d]+(?:\&[_\.\d]+)+\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)+\))+\))/g) {
		my $orig=$sub;

		my ($factor) = ($sub=~/\(\(([_\.\d]+\&(:?[_\.\d]+\&)*)(?:[_\.\d]+\&*)+\)(?:\|\(\1(?:[_\.\d]+\&*)+\))+\)/);
		next if (!defined($factor));

		$sub=~s/\Q$factor\E//g;
		$sub=~s/^\(/\($factor\(/;
		$sub.=')';
		$sub=simplify($sub);
		$expr=~s/\Q$orig\E/$sub/;
	    }
	    $hash{$key}=$expr;
	    unless (defined($captured{$expr})) {
		$condcounter++;
		$captured{$expr}=$condcounter;
		$acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;
	    } 
	} elsif ($key=~/^param_(\d+)\.(\d+)/) {
	    my $prefix=&Apache::lonnet::encode_symb($hash{'map_id_'.$1},$2,
						    $hash{'src_'.$1.'.'.$2});
	    foreach my $param (split(/\&/,$hash{$key})) {
		my ($typename,$value)=split(/\=/,$param);
		my ($type,$name)=split(/\:/,$typename);
		$parmhash{$prefix.'.'.&unescape($name)}=
		    &unescape($value);
		$parmhash{$prefix.'.'.&unescape($name).'.type'}=
		    &unescape($type);
	    }
	}
    }
    foreach my $key (keys(%hash)) {
	if ($key=~/^ids/) {
	    foreach my $resid (split(/\,/,$hash{$key})) {
		my $uri=$hash{'src_'.$resid};
		my ($uripath,$urifile) =
		    &Apache::lonnet::split_uri_for_cond($uri);
		if ($uripath) {
		    my $uricond='0';
		    if (defined($hash{'conditions_'.$resid})) {
			$uricond=$captured{$hash{'conditions_'.$resid}};
		    }
		    if (defined($acchash{'acc.res.'.$short.'.'.$uripath})) {
			if ($acchash{'acc.res.'.$short.'.'.$uripath}=~
			    /(\&\Q$urifile\E\:[^\&]*)/) {
			    my $replace=$1;
			    my $regexp=$replace;
			    #$regexp=~s/\|/\\\|/g;
			    $acchash{'acc.res.'.$short.'.'.$uripath} =~
				s/\Q$regexp\E/$replace\|$uricond/;
			} else {
			    $acchash{'acc.res.'.$short.'.'.$uripath}.=
				$urifile.':'.$uricond.'&';
			}
		    } else {
			$acchash{'acc.res.'.$short.'.'.$uripath}=
			    '&'.$urifile.':'.$uricond.'&';
		    }
		} 
	    }
	}
    }
    $acchash{'acc.res.'.$short.'.'}='&:0&';
    my $courseuri=$uri;
    $courseuri=~s/^\/res\///;
    &Apache::lonnet::delenv('(acc\.|httpref\.)');
    &Apache::lonnet::appenv(%acchash);
}

# ---------------- Selectively delete from randompick maps and hidden url parms

sub hiddenurls {
    my $randomoutentry='';
    foreach my $rid (keys %randompick) {
        my $rndpick=$randompick{$rid};
        my $mpc=$hash{'map_pc_'.$hash{'src_'.$rid}};
# ------------------------------------------- put existing resources into array
        my @currentrids=();
        foreach my $key (sort(keys(%hash))) {
	    if ($key=~/^src_($mpc\.\d+)/) {
		if ($hash{'src_'.$1}) { push @currentrids, $1; }
            }
        }
	# rids are number.number and we want to numercially sort on 
        # the second number
	@currentrids=sort {
	    my (undef,$aid)=split(/\./,$a);
	    my (undef,$bid)=split(/\./,$b);
	    $aid <=> $bid;
	} @currentrids;
        next if ($#currentrids<$rndpick);
# -------------------------------- randomly eliminate the ones that should stay
	my (undef,$id)=split(/\./,$rid);
        if ($randompickseed{$rid}) { $id=$randompickseed{$rid}; }
	my $rndseed=&Apache::lonnet::rndseed($id); # use id instead of symb
	&Apache::lonnet::setup_random_from_rndseed($rndseed);
	my @whichids=&Math::Random::random_permuted_index($#currentrids+1);
        for (my $i=1;$i<=$rndpick;$i++) { $currentrids[$whichids[$i]]=''; }
	#&Apache::lonnet::logthis("$id,$rndseed,".join(':',@whichids));
# -------------------------------------------------------- delete the leftovers
        for (my $k=0; $k<=$#currentrids; $k++) {
            if ($currentrids[$k]) {
		$hash{'randomout_'.$currentrids[$k]}=1;
                my ($mapid,$resid)=split(/\./,$currentrids[$k]);
                $randomoutentry.='&'.
		    &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},
						 $resid,
						 $hash{'src_'.$currentrids[$k]}
						 ).'&';
            }
        }
    }
# ------------------------------ take care of explicitly hidden urls or folders
    foreach my $rid (keys %hiddenurl) {
	$hash{'randomout_'.$rid}=1;
	my ($mapid,$resid)=split(/\./,$rid);
	$randomoutentry.='&'.
	    &Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,
					 $hash{'src_'.$rid}).'&';
    }
# --------------------------------------- append randomout entry to environment
    if ($randomoutentry) {
	&Apache::lonnet::appenv('acc.randomout' => $randomoutentry);
    }
}

# ---------------------------------------------------- Read map and all submaps

sub readmap {
    my $short=shift;
    $short=~s/^\///;
    my %cenv=&Apache::lonnet::coursedescription($short,{'freshen_cache'=>1});
    my $fn=$cenv{'fn'};
    my $uri;
    $short=~s/\//\_/g;
    unless ($uri=$cenv{'url'}) { 
	&Apache::lonnet::logthis("<font color=blue>WARNING: ".
				 "Could not load course $short.</font>"); 
	return ('',&mt('No course data available.'));;
    }
    @cond=('true:normal');

    open(LOCKFILE,">$fn.db.lock");
    my $lock=0;
    if (flock(LOCKFILE,LOCK_EX|LOCK_NB)) {
	$lock=1;
	unlink($fn.'.db');
	unlink($fn.'_symb.db');
	unlink($fn.'.state');
	unlink($fn.'parms.db');
    }
    undef %randompick;
    undef %hiddenurl;
    undef %encurl;
    $retfrid='';
    if ($lock && (tie(%hash,'GDBM_File',"$fn.db",&GDBM_WRCREAT(),0640)) &&
	(tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_WRCREAT(),0640))) {
	%hash=();
	%parmhash=();
	$errtext='';
	$pc=0;
	&processversionfile(%cenv);
	my $furi=&Apache::lonnet::clutter($uri);
	$hash{'src_0.0'}=&versiontrack($furi);
	$hash{'title_0.0'}=&Apache::lonnet::metadata($uri,'title');
	$hash{'ids_'.$furi}='0.0';
	$hash{'is_map_0.0'}=1;
	loadmap($uri);
	if (defined($hash{'map_start_'.$uri})) {
	    &Apache::lonnet::appenv("request.course.id"  => $short,
				    "request.course.fn"  => $fn,
				    "request.course.uri" => $uri);
	    $env{'request.course.id'}=$short;
	    &traceroute('0',$hash{'map_start_'.$uri},'&');
	    &accinit($uri,$short,$fn);
	    &hiddenurls();
	}
# ------------------------------------------------------- Put versions into src
	foreach my $key (keys(%hash)) {
	    if ($key=~/^src_/) {
		$hash{$key}=&putinversion($hash{$key});
	    } elsif ($key =~ /^(map_(?:start|finish|pc)_)(.*)/) {
		my ($type, $url) = ($1,$2);
		my $value = $hash{$key};
		$hash{$type.&putinversion($url)}=$value;
	    }
	}
# ---------------------------------------------------------------- Encrypt URLs
	foreach my $id (keys(%encurl)) {
#	    $hash{'src_'.$id}=&Apache::lonenc::encrypted($hash{'src_'.$id});
	    $hash{'encrypted_'.$id}=1;
	}
# ----------------------------------------------- Close hashes to finally store
# --------------------------------- Routine must pass this point, no early outs
	$hash{'first_rid'}=$retfrid;
	my ($mapid,$resid)=split(/\./,$retfrid);
	$hash{'first_mapurl'}=$hash{'map_id_'.$mapid};
	my $symb=&Apache::lonnet::encode_symb($hash{'map_id_'.$mapid},$resid,$hash{'src_'.$retfrid});
	$retfurl=&add_get_param($hash{'src_'.$retfrid},{ 'symb' => $symb });
	if ($hash{'encrypted_'.$retfrid}) {
	    $retfurl=&Apache::lonenc::encrypted($retfurl,(&Apache::lonnet::allowed('adv') ne 'F'));
	}
	$hash{'first_url'}=$retfurl;
	unless ((untie(%hash)) && (untie(%parmhash))) {
	    &Apache::lonnet::logthis("<font color=blue>WARNING: ".
				     "Could not untie coursemap $fn for $uri.</font>"); 
	}
# ---------------------------------------------------- Store away initial state
	{
	    my $cfh;
	    if (open($cfh,">$fn.state")) {
		print $cfh join("\n",@cond);
	    } else {
		&Apache::lonnet::logthis("<font color=blue>WARNING: ".
					 "Could not write statemap $fn for $uri.</font>"); 
	    }
	}
	flock(LOCKFILE,LOCK_UN);
	close(LOCKFILE);
    } else {
	# if we are here it is likely because we are already trying to 
	# initialize the course in another child, busy wait trying to 
	# tie the hashes for the next 90 seconds, if we succeed forward 
	# them on to navmaps, if we fail, throw up the Could not init 
	# course screen
	if ($lock) {
	    # Got the lock but not the DB files
	    flock(LOCKFILE,LOCK_UN);
	}
	untie(%hash);
	untie(%parmhash);
	&Apache::lonnet::logthis("<font color=blue>WARNING: ".
				 "Could not tie coursemap $fn for $uri.</font>"); 
	my $i=0;
	while($i<90) {
	    $i++;
	    sleep(1);
	    if (flock(LOCKFILE,LOCK_EX|LOCK_NB) &&
		(tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640))) {
		if (tie(%parmhash,'GDBM_File',$fn.'_parms.db',&GDBM_READER(),0640)) {
		    $retfurl='/adm/navmaps';
		    &Apache::lonnet::appenv("request.course.id"  => $short,
					    "request.course.fn"  => $fn,
					    "request.course.uri" => $uri);
		    untie(%hash);
		    untie(%parmhash);
		    last;
		}
	    }
	    untie(%hash);
	    untie(%parmhash);
	}
	flock(LOCKFILE,LOCK_UN);
	close(LOCKFILE);
    }
    &Apache::lonmsg::author_res_msg($env{'request.course.uri'},$errtext);
# ------------------------------------------------- Check for critical messages

    my @what=&Apache::lonnet::dump('critical',$env{'user.domain'},
				   $env{'user.name'});
    if ($what[0]) {
	if (($what[0] ne 'con_lost') && ($what[0]!~/^error\:/)) {
	    $retfurl='/adm/email?critical=display';
        }
    }
    return ($retfurl,$errtext);
}

# ------------------------------------------------------- Evaluate state string

sub evalstate {
    my $fn=$env{'request.course.fn'}.'.state';
    my $state='';
    if (-e $fn) {
	my @conditions=();
	{
	    open(my $fh,"<$fn");
	    @conditions=<$fh>;
            close($fh);
	}  
	my $safeeval = new Safe;
	my $safehole = new Safe::Hole;
	$safeeval->permit("entereval");
	$safeeval->permit(":base_math");
	$safeeval->deny(":base_io");
	$safehole->wrap(\&Apache::lonnet::EXT,$safeeval,'&EXT');
	foreach my $line (@conditions) {
	    chomp($line);
	    my ($condition,$weight)=split(/\:/,$line);
	    if ($safeeval->reval($condition)) {
		if ($weight eq 'force') {
		    $state.='3';
		} else {
		    $state.='2';
		}
	    } else {
		if ($weight eq 'stop') {
		    $state.='0';
		} else {
		    $state.='1';
		}
	    }
	}
    }
    &Apache::lonnet::appenv('user.state.'.$env{'request.course.id'} => $state);
    return $state;
}

1;
__END__

=head1 NAME

Apache::lonuserstate - Construct and maintain state and binary representation
of course for user

=head1 SYNOPSIS

Invoked by lonroles.pm.

&Apache::lonuserstate::readmap($cdom.'/'.$cnum);

=head1 INTRODUCTION

This module constructs and maintains state and binary representation
of course for user.

This is part of the LearningOnline Network with CAPA project
described at http://www.lon-capa.org.

=head1 HANDLER SUBROUTINE

There is no handler subroutine.

=head1 OTHER SUBROUTINES

=over 4

=item *

loadmap() : Loads map from disk

=item *

simplify() : Simplify expression

=item *

traceroute() : Build condition hash

=item *

accinit() : Cascading conditions, quick access, parameters

=item *

readmap() : Read map and all submaps

=item *

evalstate() : Evaluate state string

=back

=cut

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator at root@localhost to inform them of the time this error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.