Annotation of loncom/lonmap.pm, revision 1.9

1.1       foxr        1: # The LearningOnline Network
                      2: #
                      3: #  Read maps into a 'big hash'.
                      4: #
1.9     ! raeburn     5: # $Id: lonmap.pm,v 1.8 2012/12/20 16:10:57 raeburn Exp $
1.1       foxr        6: #
                      7: # Copyright Michigan State University Board of Trustees
                      8: #
                      9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
                     10: #
                     11: # LON-CAPA is free software; you can redistribute it and/or modify
                     12: # it under the terms of the GNU General Public License as published by
                     13: # the Free Software Foundation; either version 2 of the License, or
                     14: # (at your option) any later version.
                     15: #
                     16: # LON-CAPA is distributed in the hope that it will be useful,
                     17: # but WITHOUT ANY WARRANTY; without even the implied warranty of
                     18: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     19: # GNU General Public License for more details.
                     20: #
                     21: # You should have received a copy of the GNU General Public License
                     22: # along with LON-CAPA; if not, write to the Free Software
                     23: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
                     24: #
                     25: # /home/httpd/html/adm/gpl.txt
                     26: #
                     27: # http://www.lon-capa.org/
                     28: #
                     29: ###
                     30: 
1.3       foxr       31: package Apache::lonmap;
1.1       foxr       32: use strict;
                     33: 
                     34: #------------- Required external modules.
                     35: 
                     36: use Error qw(:try);
                     37: 
                     38: use HTML::TokeParser;
                     39: 
                     40: 
1.2       foxr       41: use LONCAPA;
1.1       foxr       42: use Apache::lonnet;
1.6       foxr       43: use Apache::lonlocal;
                     44: 
1.3       foxr       45: use Data::Dumper;
                     46: 
1.1       foxr       47: 
                     48: #------------- File scoped variables:
                     49: 
1.3       foxr       50: my $map_number = 0;		# keep track of maps within the course.
1.1       foxr       51: my $course_id;     		# Will be the id of the course being read in.
                     52: 
                     53: #
                     54: # The variables below are auxiliary hashes.  They will be tacked onto the
                     55: # big hash though currently not used by clients.. you never know about later.
                     56: #
                     57: 
                     58: my %randompick;
                     59: my %randompickseed;
                     60: my %randomorder;
                     61: my %encurl;
                     62: my %hiddenurl;
1.2       foxr       63: my %parmhash;
1.1       foxr       64: my @cond;			# Array of conditions.
1.2       foxr       65: my $retfrid;
1.1       foxr       66: #
                     67: #  Other stuff we make global (sigh) so that it does not need
                     68: #  to be passed around all the time:
                     69: #
                     70: 
                     71: my $username;			# User for whom the map is being read.
                     72: my $userdomain;  		# Domain the user lives in.
1.6       foxr       73: my $short_name;			# Course shortname.
1.1       foxr       74: my %mapalias_cache;		# Keeps track of map aliases -> resources detects duplicates.
1.3       foxr       75: my %cenv;			# Course environment.
1.1       foxr       76: 
                     77: #------------- Executable code: 
                     78: 
                     79: 
                     80: #----------------------------------------------------------------
                     81: #
                     82: #  General utilities:
                     83: 
                     84: 
                     85: #
                     86: #  I _think_ this does common sub-expression simplification and 
                     87: #  optimization for condition strings...based on common pattern matching.
                     88: # Parameters:
                     89: #    expression - the condition expression string.
                     90: # Returns:
                     91: #    The optimized expression if an optimization could be found.
                     92: #
                     93: # NOTE:
                     94: #   Added repetetive optimization..it's possible that an
                     95: #   optimization results in an expression that can be recognized further in
                     96: #   a subsequent optimization pass:
                     97: #
                     98: 
                     99: sub simplify {
                    100:     my $expression=shift;
1.4       foxr      101: 
1.1       foxr      102: # (0&1) = 1
                    103: 	$expression=~s/\(0\&([_\.\d]+)\)/$1/g;
                    104: # (8)=8
                    105: 	$expression=~s/\(([_\.\d]+)\)/$1/g;
                    106: # 8&8=8
                    107: 	$expression=~s/([^_\.\d])([_\.\d]+)\&\2([^_\.\d])/$1$2$3/g;
                    108: # 8|8=8
                    109: 	$expression=~s/([^_\.\d])([_\.\d]+)(?:\|\2)+([^_\.\d])/$1$2$3/g;
                    110: # (5&3)&4=5&3&4
                    111: 	$expression=~s/\(([_\.\d]+)((?:\&[_\.\d]+)+)\)\&([_\.\d]+[^_\.\d])/$1$2\&$3/g;
                    112: # (((5&3)|(4&6)))=((5&3)|(4&6))
                    113: 	$expression=~
                    114: 	    s/\((\(\([_\.\d]+(?:\&[_\.\d]+)*\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+\))\)/$1/g;
                    115: # ((5&3)|(4&6))|(1&2)=(5&3)|(4&6)|(1&2)
                    116: 	$expression=~
                    117: 	    s/\((\([_\.\d]+(?:\&[_\.\d]+)*\))((?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+)\)\|(\([_\.\d]+(?:\&[_\.\d]+)*\))/\($1$2\|$3\)/g;
1.4       foxr      118: 
                    119: 
1.1       foxr      120:     return $expression;
                    121: }
                    122:     
                    123: 
                    124: #
                    125: #  Merge the conditions into the big hash
                    126: #  these will result in hash entries of the form:
                    127: #   'condition.n'  where 'n' is the array index of the condition in the
                    128: #   @cond array above.
                    129: #
                    130: #  Parameters:
                    131: #    $hash - big hashthat's being built up.
                    132: #
                    133: sub merge_conditions {
                    134:     my $hash = shift;
                    135: 
1.2       foxr      136:     for (my $i = 0; $i < scalar(@cond); $i++) {
1.1       foxr      137: 	$hash->{'condition' . '.' . $i} = $cond[$i];
                    138:     }
                    139: }
                    140: 
                    141: # Merge the contents of a 'child hash' into a parent hash hanging it off another key.
                    142: # This is _not_ done by hanging a reference to the child hash as the parent may be
                    143: # bound to a GDBM file e.g. and shared by more than one process ..and references are
                    144: # pretty clearly not going to work across process boundaries.
                    145: #
                    146: # Parameters:
                    147: #   $parent  - The hash to which the child will be merged (reference)
                    148: #   $key     - The key in the parent hash on which the child elements will be hung.
                    149: #              given a key named $childkey the final parent hash entry will be
                    150: #              $parent . '.' $childkey
                    151: #  $child    - The hash whose contents we merge into the parent (reference)
                    152: #
                    153: sub merge_hash {
                    154:     my ($parent, $key, $child) = @_;
                    155: 
1.3       foxr      156:     if ($key ne '') {
                    157: 	$key .= '.';		# If we are prefixing, prefix then .
                    158:     }
                    159: 
1.1       foxr      160:     foreach my $childkey (keys (%$child)) {
1.3       foxr      161: 	$parent->{$key . $childkey} = $child->{$childkey};
1.1       foxr      162:     }
                    163: }
                    164: 
                    165: #----------------------------------------------------------------------------------
                    166: #
                    167: #   Code to keep track of map aliases and to determine if there are doubly 
                    168: #   defined aliases.
                    169: #
                    170: 
                    171: #
                    172: #  Maintains the mapalias hash.  This is a hash of arrays.  Each array
                    173: #  is indexed by the alias and contains the set of resource ids pointed to by that
                    174: #  alias.  In an ideal world, there will only be one element in each array.
                    175: #  The point of this, however is to determine which aliases might be doubley defined
                    176: #  due to map nesting e.g.
                    177: #
                    178: #  Parameters:
                    179: #    $value   - Alias name.
                    180: #    $resid   - Resource id pointed to by the alias.
                    181: #
                    182: #    
                    183: sub count_mapalias {
                    184:     my ($value,$resid) = @_;
                    185:     push(@{ $mapalias_cache{$value} }, $resid);
                    186: }
                    187: #
                    188: #  Looks at each key in the mapalias hash and, for each case where an
                    189: #  alias points to more than one value adds an error text to the
                    190: #  result string.'
                    191: #
                    192: #  Parameters:
1.2       foxr      193: #     hash - Reference to the hash we are trying t build up.
1.1       foxr      194: #  Implicit inputs
                    195: #     %mapalias - a hash that is indexed by map aliases and contains for each key
                    196: #                 an array of the resource id's the alias 'points to'.
                    197: # Returns:
                    198: #    A hopefully empty string of messages that descsribe the aliases that have more
                    199: #    than one value.  This string is formatted like an html list.
                    200: #
                    201: #
                    202: sub get_mapalias_errors {
1.2       foxr      203:     my $hash = shift;
1.1       foxr      204:     my $error_text;
                    205:     foreach my $mapalias (sort(keys(%mapalias_cache))) {
                    206: 	next if (scalar(@{ $mapalias_cache{$mapalias} } ) == 1);
                    207: 	my $count;
                    208: 	my $which =
                    209: 	    join('</li><li>', 
                    210: 		 map {
                    211: 		     my $id = $_;
1.2       foxr      212: 		     if (exists($hash->{'src_'.$id})) {
1.1       foxr      213: 			 $count++;
                    214: 		     }
                    215: 		     my ($mapid) = split(/\./,$id);
                    216: 		     &mt('Resource "[_1]" <br /> in Map "[_2]"',
1.2       foxr      217: 			 $hash->{'title_'.$id},
                    218: 			 $hash->{'title_'.$hash->{'ids_'.$hash->{'map_id_'.$mapid}}});
1.1       foxr      219: 		 } (@{ $mapalias_cache{$mapalias} }));
                    220: 	next if ($count < 2);
                    221: 	$error_text .= '<div class="LC_error">'.
                    222: 	    &mt('Error: Found the mapalias "[_1]" defined multiple times.',
                    223: 		$mapalias).
                    224: 		'</div><ul><li>'.$which.'</li></ul>';
                    225:     }
                    226:     &clear_mapalias_count();
                    227:     return $error_text;
                    228: }
                    229: #
                    230: #   Clears the map aliase hash.
                    231: #
                    232: sub clear_mapalias_count {
                    233:     undef(%mapalias_cache);
                    234: }
                    235: 
                    236: #----------------------------------------------------------------
                    237: #
                    238: #  Code dealing with resource versions.
                    239: #
                    240: 
                    241: #
1.2       foxr      242: #  Put a version into a src element of a hash or url:
                    243: #
                    244: #  Parameters:
                    245: #     uri - URI into which the version must be added.
                    246: #    hash - Reference to the hash being built up.
                    247: #    short- Short coursename.
                    248: #
                    249: 
                    250: sub putinversion {
                    251:     my ($uri, $hash, $short) = @_;
                    252:     my $key=$short.'_'.&Apache::lonnet::clutter($uri);
                    253:     if ($hash->{'version_'.$uri}) {
                    254: 	my $version=$hash->{'version_'.$uri};
                    255: 	if ($version eq 'mostrecent') { return $uri; }
                    256: 	if ($version eq &Apache::lonnet::getversion(
                    257: 			&Apache::lonnet::filelocation('',$uri))) 
                    258: 	             { return $uri; }
                    259: 	$uri=~s/\.(\w+)$/\.$version\.$1/;
                    260:     }
                    261:     &Apache::lonnet::do_cache_new('courseresversion',$key,&Apache::lonnet::declutter($uri),600);
                    262:     return $uri;
                    263: }
                    264: 
                    265: 
                    266: #
1.1       foxr      267: #  Create hash entries for each version of the course.
                    268: # Parameters:
                    269: #   $cenv    - Reference to a course environment from lonnet::coursedescription.
                    270: #   $hash    - Reference to a hash that will be populated.
                    271: 
                    272: #
                    273: sub process_versions {
                    274:     my ($cenv, $hash) = @_;
                    275: 
                    276:     
                    277:     my %versions = &Apache::lonnet::dump('resourceversions',
                    278: 					 $cenv->{'domain'},
                    279: 					 $cenv->{'num'});
                    280: 
                    281:     foreach my $ver (keys (%versions)) {
                    282: 	if ($ver =~/^error\:/) { # lonc/lond transaction failed.
                    283: 	    throw Error::Simple('lonc/lond returned error: ' . $ver);
                    284: 	}
                    285: 	$hash->{'version_'.$ver} = $versions{$ver};
                    286:     }
                    287: }
                    288: 
                    289: #
                    290: #  Generate text for a version discrepancy error:
                    291: # Parameters:
                    292: #  $uri   - URI of the resource.
                    293: #  $used  - Version used.
                    294: #  $unused - Veresion of duplicate.
                    295: #
                    296: sub versionerror {
                    297:     my ($uri, $used, $unused) = @_;
                    298:     return '<br />'.
                    299: 	&mt('Version discrepancy: resource [_1] included in both version [_2] and version [_3]. Using version [_2].',
                    300: 	    $uri,$used,$unused).'<br />';
                    301: 
                    302: }
                    303: 
                    304: #  Removes the version number from a URI and returns the resulting
                    305: #  URI (e.g. mumbly.version.stuff => mumbly.stuff).
                    306: #
                    307: #   If the URI has not been seen with a version before the
                    308: #   hash{'version_'.resultingURI} is set to the  version number.
                    309: #   If the hash has already been seen, but differs then
                    310: #   an error is raised.
                    311: #
                    312: # Parameters:
                    313: #   $uri  -  potentially with a version.
                    314: #   $hash -  reference to a hash to fill in. 
                    315: # Returns:
                    316: #   URI with the version cut out.
                    317: #
1.3       foxr      318: sub versiontrack {
1.1       foxr      319:     my ($uri, $hash) = @_;
                    320: 
                    321: 
                    322:     if ($uri=~/\.(\d+)\.\w+$/) { # URI like *.n.text it's version 'n'
                    323: 	my $version=$1;
                    324: 	$uri=~s/\.\d+\.(\w+)$/\.$1/; # elide the version.
                    325:         unless ($hash->{'version_'.$uri}) {
                    326: 	    $hash->{'version_'.$uri}=$version;
                    327: 	} elsif ($version!=$hash->{'version_'.$uri}) {
1.2       foxr      328: 	    throw Error::Simple(&versionerror($uri, $hash->{'version_'.$uri}, $version));
1.1       foxr      329:         }
                    330:     }
                    331:     return $uri;
                    332: }
                    333: #
                    334: #  Appends the version of a resource to its uri and also caches the 
                    335: #  URI (contents?) on the local server
                    336: #
                    337: #  Parameters:
                    338: #     $uri   - URI of the course (without version informatino.
                    339: #     $hash  - What we have of  the big hash.
                    340: #
                    341: # Side-Effects:
                    342: #   The URI is cached by memcached.
                    343: #
                    344: # Returns:
                    345: #    The version appended URI.
                    346: #
                    347: sub append_version {
                    348:     my ($uri, $hash) = @_;
                    349: 
                    350:     # Create the key for the cache entry.
                    351: 
                    352:     my $key = $course_id . '_' . &Apache::lonnet::clutter($uri);
                    353: 
                    354:     # If there is a version it will already be  in the hash:
                    355: 
                    356:     if ($hash->{'version_' . $uri}) {
                    357: 	my $version = $hash->{'version_' . $uri};
                    358: 	if ($version eq 'mostrecent') {
                    359: 	    return $uri;     # Most recent version does not require decoration (or caching?).
                    360: 	}
                    361: 	if ($version eq 
                    362: 	    &Apache::lonnet::getversion(&Apache::lonnet::filelocation('', $uri))) {
                    363: 	    return $uri;	# version matches the most recent file version?
                    364: 	}
                    365: 	$uri =~ s/\.(\w+)$/\.$version\.$1/; # insert the versino prior to the last .word.
                    366:     }
                    367:  
                    368:    # cache the version:
                    369: 
                    370:    &Apache::lonnet::do_cache_new('courseresversion', $key, 
                    371: 				 &Apache::lonnet::declutter($uri), 600);
                    372: 
                    373:     return $uri;
                    374: 
                    375: }
1.6       foxr      376: #------------------------------------------------------------------------------
                    377: #
                    378: #  Misc. utilities that don't fit into the other classifications.
                    379: 
                    380: # Determine if the specified user has an 'advanced' role in a course.
                    381: # Parameters:
                    382: #   cenv       - reference to a course environment.
                    383: #   username   - Name of the user we care about.
                    384: #   domain     - Domain in which the user is defined.
                    385: # Returns:
                    386: #    0  - User does not have an advanced role in the course.
                    387: #    1  - User does have an advanced role in the course.
                    388: #
                    389: sub has_advanced_role {
                    390:     my ($username, $domain) = @_;
                    391: 
                    392:     my %adv_roles = &Apache::lonnet::get_course_adv_roles($short_name);
                    393:     my $merged_username = $username . ':' . $domain;
                    394:     foreach my $user (values %adv_roles) {
                    395: 	if ($merged_username eq $user) {
                    396: 	    return 1;
                    397: 	}
                    398:     }
                    399:     return 0;
                    400: }
                    401: 
1.1       foxr      402: #--------------------------------------------------------------------------------
                    403: # Post processing subs:
                    404: sub hiddenurls {
                    405:     my $hash = shift;
                    406: 
1.3       foxr      407:     my $uname    = $hash->{'context.username'};
                    408:     my $udom     = $hash->{'context.userdom'};
                    409:     my $courseid = $hash->{'context.courseid'};
                    410: 
1.1       foxr      411:     my $randomoutentry='';
                    412:     foreach my $rid (keys %randompick) {
                    413:         my $rndpick=$randompick{$rid};
                    414:         my $mpc=$hash->{'map_pc_'.$hash->{'src_'.$rid}};
                    415: # ------------------------------------------- put existing resources into array
                    416:         my @currentrids=();
                    417:         foreach my $key (sort(keys(%$hash))) {
                    418: 	    if ($key=~/^src_($mpc\.\d+)/) {
                    419: 		if ($hash->{'src_'.$1}) { push @currentrids, $1; }
                    420:             }
                    421:         }
                    422: 	# rids are number.number and we want to numercially sort on 
                    423:         # the second number
                    424: 	@currentrids=sort {
                    425: 	    my (undef,$aid)=split(/\./,$a);
                    426: 	    my (undef,$bid)=split(/\./,$b);
                    427: 	    $aid <=> $bid;
                    428: 	} @currentrids;
                    429:         next if ($#currentrids<$rndpick);
                    430: # -------------------------------- randomly eliminate the ones that should stay
                    431: 	my (undef,$id)=split(/\./,$rid);
                    432:         if ($randompickseed{$rid}) { $id=$randompickseed{$rid}; }
1.3       foxr      433: 	my $rndseed=&Apache::lonnet::rndseed($id, $courseid, $udom, $uname, \%cenv); # use id instead of symb
1.1       foxr      434: 	&Apache::lonnet::setup_random_from_rndseed($rndseed);
                    435: 	my @whichids=&Math::Random::random_permuted_index($#currentrids+1);
                    436:         for (my $i=1;$i<=$rndpick;$i++) { $currentrids[$whichids[$i]]=''; }
1.3       foxr      437: 
1.1       foxr      438: # -------------------------------------------------------- delete the leftovers
                    439:         for (my $k=0; $k<=$#currentrids; $k++) {
                    440:             if ($currentrids[$k]) {
1.3       foxr      441: 		$hash->{'randomout_'.$currentrids[$k]}='1';
1.1       foxr      442:                 my ($mapid,$resid)=split(/\./,$currentrids[$k]);
                    443:                 $randomoutentry.='&'.
                    444: 		    &Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},
                    445: 						 $resid,
                    446: 						 $hash->{'src_'.$currentrids[$k]}
                    447: 						 ).'&';
                    448:             }
                    449:         }
                    450:     }
                    451: # ------------------------------ take care of explicitly hidden urls or folders
                    452:     foreach my $rid (keys %hiddenurl) {
1.3       foxr      453: 	$hash->{'randomout_'.$rid}='1';
1.1       foxr      454: 	my ($mapid,$resid)=split(/\./,$rid);
                    455: 	$randomoutentry.='&'.
                    456: 	    &Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},$resid,
                    457: 					 $hash->{'src_'.$rid}).'&';
                    458:     }
                    459: # --------------------------------------- add randomout to the hash.
                    460:     if ($randomoutentry) {
                    461: 	$hash->{'acc.randomout'} = $randomoutentry;
                    462: 
                    463:     }
                    464: }
                    465: 
                    466: #
                    467: # It's not so clear to me what this sub does.
                    468: #
                    469: #  Parameters
                    470: #     uri   - URI from the course description hash.
                    471: #     short - Course short name.
                    472: #     fn    - Course filename.
                    473: #     hash  - Reference to the big hash as filled in so far
                    474: #       
                    475: 
                    476: sub accinit {
1.3       foxr      477:     my ($uri, $short, $hash)=@_;
1.1       foxr      478:     my %acchash=();
                    479:     my %captured=();
                    480:     my $condcounter=0;
                    481:     $acchash{'acc.cond.'.$short.'.0'}=0;
                    482: 
                    483:     # This loop is only interested in conditions and 
                    484:     # parameters in the big hash:
                    485: 
                    486:     foreach my $key (keys(%$hash)) {
                    487: 
                    488: 	# conditions:
                    489: 
                    490: 	if ($key=~/^conditions/) {
                    491: 	    my $expr=$hash->{$key};
                    492: 
                    493: 	    # try to find and factor out common sub-expressions
                    494: 	    # Any subexpression that is found is simplified, removed from
                    495: 	    # the original condition expression and the simplified sub-expression
                    496: 	    # substituted back in to the epxression..I'm not actually convinced this
                    497: 	    # factors anything out...but instead maybe simplifies common factors(?)
                    498: 
                    499: 	    foreach my $sub ($expr=~m/(\(\([_\.\d]+(?:\&[_\.\d]+)+\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)+\))+\))/g) {
                    500: 		my $orig=$sub;
                    501: 
                    502: 		my ($factor) = ($sub=~/\(\(([_\.\d]+\&(:?[_\.\d]+\&)*)(?:[_\.\d]+\&*)+\)(?:\|\(\1(?:[_\.\d]+\&*)+\))+\)/);
                    503: 		next if (!defined($factor));
                    504: 
                    505: 		$sub=~s/\Q$factor\E//g;
                    506: 		$sub=~s/^\(/\($factor\(/;
                    507: 		$sub.=')';
                    508: 		$sub=simplify($sub);
                    509: 		$expr=~s/\Q$orig\E/$sub/;
                    510: 	    }
                    511: 	    $hash->{$key}=$expr;
                    512: 
                    513:            # If not yet seen, record in acchash and that we've seen it.
                    514: 
                    515: 	    unless (defined($captured{$expr})) {
                    516: 		$condcounter++;
                    517: 		$captured{$expr}=$condcounter;
                    518: 		$acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;
                    519: 	    } 
                    520:         # Parameters:
                    521: 
                    522: 	} elsif ($key=~/^param_(\d+)\.(\d+)/) {
                    523: 	    my $prefix=&Apache::lonnet::encode_symb($hash->{'map_id_'.$1},$2,
                    524: 						    $hash->{'src_'.$1.'.'.$2});
                    525: 	    foreach my $param (split(/\&/,$hash->{$key})) {
                    526: 		my ($typename,$value)=split(/\=/,$param);
                    527: 		my ($type,$name)=split(/\:/,$typename);
                    528: 		$parmhash{$prefix.'.'.&unescape($name)}=
                    529: 		    &unescape($value);
                    530: 		$parmhash{$prefix.'.'.&unescape($name).'.type'}=
                    531: 		    &unescape($type);
                    532: 	    }
                    533: 	}
                    534:     }
                    535:     # This loop only processes id entries in the big hash.
                    536: 
                    537:     foreach my $key (keys(%$hash)) {
                    538: 	if ($key=~/^ids/) {
                    539: 	    foreach my $resid (split(/\,/,$hash->{$key})) {
                    540: 		my $uri=$hash->{'src_'.$resid};
                    541: 		my ($uripath,$urifile) =
                    542: 		    &Apache::lonnet::split_uri_for_cond($uri);
                    543: 		if ($uripath) {
                    544: 		    my $uricond='0';
                    545: 		    if (defined($hash->{'conditions_'.$resid})) {
                    546: 			$uricond=$captured{$hash->{'conditions_'.$resid}};
                    547: 		    }
                    548: 		    if (defined($acchash{'acc.res.'.$short.'.'.$uripath})) {
                    549: 			if ($acchash{'acc.res.'.$short.'.'.$uripath}=~
                    550: 			    /(\&\Q$urifile\E\:[^\&]*)/) {
                    551: 			    my $replace=$1;
                    552: 			    my $regexp=$replace;
                    553: 			    #$regexp=~s/\|/\\\|/g;
                    554: 			    $acchash{'acc.res.'.$short.'.'.$uripath} =~
                    555: 				s/\Q$regexp\E/$replace\|$uricond/;
                    556: 			} else {
                    557: 			    $acchash{'acc.res.'.$short.'.'.$uripath}.=
                    558: 				$urifile.':'.$uricond.'&';
                    559: 			}
                    560: 		    } else {
                    561: 			$acchash{'acc.res.'.$short.'.'.$uripath}=
                    562: 			    '&'.$urifile.':'.$uricond.'&';
                    563: 		    }
                    564: 		} 
                    565: 	    }
                    566:         }
                    567:     }
                    568:     $acchash{'acc.res.'.$short.'.'}='&:0&';
                    569:     my $courseuri=$uri;
                    570:     $courseuri=~s/^\/res\///;
                    571:     my $regexp = 1;
                    572:  
                    573:     &merge_hash($hash, '', \%acchash); # there's already an acc prefix in the hash keys.
                    574: 
                    575: 
                    576: }
                    577: 
                    578: 
                    579: #
                    580: #  Traces a route recursively through the map after it has been loaded
                    581: #  (I believe this really visits each resource that is reachable fromt he
                    582: #  start top node.
                    583: #
                    584: #  - Marks hidden resources as hidden.
                    585: #  - Marks which resource URL's must be encrypted.
                    586: #  - Figures out (if necessary) the first resource in the map.
                    587: #  - Further builds the chunks of the big hash that define how 
                    588: #    conditions work
                    589: #
                    590: #  Note that the tracing strategy won't visit resources that are not linked to
                    591: #  anything or islands in the map (groups of resources that form a path but are not
                    592: #  linked in to the path that can be traced from the start resource...but that's ok
                    593: #  because by definition, those resources are not reachable by users of the course.
                    594: #
                    595: # Parameters:
                    596: #   sofar    - _URI of the prior entry or 0 if this is the top.
                    597: #   rid      - URI of the resource to visit.
                    598: #   beenhere - list of resources (each resource enclosed by &'s) that have
                    599: #              already been visited.
                    600: #   encflag  - If true the resource that resulted in a recursive call to us
                    601: #              has an encoded URL (which means contained resources should too). 
                    602: #   hdnflag  - If true,the resource that resulted in a recursive call to us
                    603: #              was hidden (which means contained resources should be hidden too).
                    604: #   hash     - Reference to the hash we are traversing.
                    605: # Returns
                    606: #    new value indicating how far the map has been traversed (the sofar).
                    607: #
                    608: sub traceroute {
1.2       foxr      609:     my ($sofar, $rid, $beenhere, $encflag, $hdnflag, $hash)=@_;
1.1       foxr      610:     my $newsofar=$sofar=simplify($sofar);
                    611: 
                    612:     unless ($beenhere=~/\&\Q$rid\E\&/) {
                    613: 	$beenhere.=$rid.'&';  
                    614: 	my ($mapid,$resid)=split(/\./,$rid);
                    615: 	my $symb=&Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},$resid,
                    616: 					      $hash->{'src_'.$rid});
                    617: 	my $hidden=&Apache::lonnet::EXT('resource.0.hiddenresource',$symb);
                    618: 
                    619: 	if ($hdnflag || lc($hidden) eq 'yes') {
                    620: 	    $hiddenurl{$rid}=1;
                    621: 	}
                    622: 	if (!$hdnflag && lc($hidden) eq 'no') {
                    623: 	    delete($hiddenurl{$rid});
                    624: 	}
                    625: 
                    626: 	my $encrypt=&Apache::lonnet::EXT('resource.0.encrypturl',$symb);
                    627: 	if ($encflag || lc($encrypt) eq 'yes') { $encurl{$rid}=1; }
                    628: 
                    629: 	if (($retfrid eq '') && ($hash->{'src_'.$rid})
                    630: 	    && ($hash->{'src_'.$rid}!~/\.sequence$/)) {
                    631: 	    $retfrid=$rid;
                    632: 	}
                    633: 
                    634: 	if (defined($hash->{'conditions_'.$rid})) {
                    635: 	    $hash->{'conditions_'.$rid}=simplify(
                    636:            '('.$hash->{'conditions_'.$rid}.')|('.$sofar.')');
                    637: 	} else {
                    638: 	    $hash->{'conditions_'.$rid}=$sofar;
                    639: 	}
                    640: 
                    641: 	# if the expression is just the 0th condition keep it
                    642: 	# otherwise leave a pointer to this condition expression
                    643: 
                    644: 	$newsofar = ($sofar eq '0') ? $sofar : '_'.$rid;
                    645: 
                    646: 	# Recurse if the resource is a map:
                    647: 
                    648: 	if (defined($hash->{'is_map_'.$rid})) {
                    649: 	    if (defined($hash->{'map_start_'.$hash->{'src_'.$rid}})) {
                    650: 		$sofar=$newsofar=
                    651: 		    &traceroute($sofar,
                    652: 				$hash->{'map_start_'.$hash->{'src_'.$rid}},
                    653: 				$beenhere,
                    654: 				$encflag || $encurl{$rid},
1.3       foxr      655: 				$hdnflag || $hiddenurl{$rid}, $hash);
1.1       foxr      656: 	    }
                    657: 	}
                    658: 
                    659: 	# Processes  links to this resource:
                    660: 	#  - verify the existence of any conditionals on the link to here.
                    661: 	#  - Recurse to any resources linked to us.
                    662: 	#
                    663: 	if (defined($hash->{'to_'.$rid})) {
                    664: 	    foreach my $id (split(/\,/,$hash->{'to_'.$rid})) {
                    665: 		my $further=$sofar;
                    666: 		#
                    667: 		# If there's a condition associated with this link be sure
                    668: 		# it's been defined else that's an error:
                    669: 		#
                    670:                 if ($hash->{'undercond_'.$id}) {
                    671: 		    if (defined($hash->{'condid_'.$hash->{'undercond_'.$id}})) {
                    672: 			$further=simplify('('.'_'.$rid.')&('.
                    673: 					  $hash->{'condid_'.$hash->{'undercond_'.$id}}.')');
                    674: 		    } else {
1.2       foxr      675: 			my $errtext.=&mt('<br />Undefined condition ID: [_1]',$hash->{'undercond_'.$id});
1.1       foxr      676: 			throw Error::Simple($errtext);
                    677: 		    }
                    678:                 }
                    679: 		#  Recurse to resoruces that have to's to us.
                    680:                 $newsofar=&traceroute($further,$hash->{'goesto_'.$id},$beenhere,
1.3       foxr      681: 				      $encflag,$hdnflag, $hash);
1.1       foxr      682: 	    }
                    683: 	}
                    684:     }
                    685:     return $newsofar;
                    686: }
                    687: 
                    688: 
                    689: #---------------------------------------------------------------------------------
                    690: #
                    691: #  Map parsing code:
                    692: #
                    693: 
                    694: # 
                    695: #  Parse the <param> tag.  for most parameters, the only action is to define/extend
                    696: #  a has entry for {'param_{refid}'} where refid is the resource the parameter is
                    697: #  attached to and the value built up is an & separated list of parameters of the form:
                    698: #  type:part.name=value
                    699: #
                    700: #   In addition there is special case code for:
                    701: #   - randompick
                    702: #   - randompickseed
                    703: #   - randomorder
                    704: #
                    705: #   - encrypturl
                    706: #   - hiddenresource
                    707: #
                    708: # Parameters:
                    709: #    token - The token array from HTML::TokeParse  we mostly care about element [2]
                    710: #            which is a hash of attribute => values supplied in the tag
                    711: #            (remember this sub is only processing start tag tokens).
                    712: #    mno   - Map number.  This is used to qualify resource ids within a map
                    713: #            to make them unique course wide (a process known as uniquifaction).
                    714: #    hash  - Reference to the hash we are building.
                    715: #
                    716: sub parse_param {
                    717:     my ($token, $mno, $hash)  = @_;
                    718: 
                    719:     # Qualify the reference and name by the map number and part number.
                    720:     # if no explicit part number is supplied, 0 is the implicit part num.
                    721: 
                    722:     my $referid=$mno.'.'.$token->[2]->{'to'}; # Resource param applies to.
                    723:     my $name=$token->[2]->{'name'};	      # Name of parameter
                    724:     my $part;
                    725: 
                    726: 
                    727:     if ($name=~/^parameter_(.*)_/) { 
                    728: 	$part=$1;
                    729:     } else {
                    730: 	$part=0;
                    731:     }
                    732: 
                    733:     # Peel the parameter_ off the parameter name.
                    734: 
                    735:     $name=~s/^.*_([^_]*)$/$1/;
                    736: 
                    737:     # The value is:
                    738:     #   type.part.name.value
                    739: 
                    740:     my $newparam=
                    741: 	&escape($token->[2]->{'type'}).':'.
                    742: 	&escape($part.'.'.$name).'='.
                    743: 	&escape($token->[2]->{'value'});
                    744: 
                    745:     # The hash key is param_resourceid.
                    746:     # Multiple parameters for a single resource are & separated in the hash.
                    747: 
                    748: 
                    749:     if (defined($hash->{'param_'.$referid})) {
                    750: 	$hash->{'param_'.$referid}.='&'.$newparam;
                    751:     } else {
                    752: 	$hash->{'param_'.$referid}=''.$newparam;
                    753:     }
                    754:     #
                    755:     #  These parameters have to do with randomly selecting
                    756:     # resources, therefore a separate hash is also created to 
                    757:     # make it easy to locate them when actually computing the resource set later on
                    758:     # See the code conditionalized by ($randomize) in read_map().
                    759: 
                    760:     if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) { # Random selection turned on
                    761: 	$randompick{$referid}=$token->[2]->{'value'};
                    762:     }
                    763:     if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) { # Randomseed provided.
                    764: 	$randompickseed{$referid}=$token->[2]->{'value'};
                    765:     }
                    766:     if ($token->[2]->{'name'}=~/^parameter_(0_)*randomorder$/) { # Random order turned on.
                    767: 	$randomorder{$referid}=$token->[2]->{'value'};
                    768:     }
                    769: 
                    770:     # These parameters have to do with how the URLs of resources are presented to
                    771:     # course members(?).  encrypturl presents encypted url's while
                    772:     # hiddenresource hides the URL.
                    773:     #
                    774: 
                    775:     if ($token->[2]->{'name'}=~/^parameter_(0_)*encrypturl$/) {
                    776: 	if ($token->[2]->{'value'}=~/^yes$/i) {
                    777: 	    $encurl{$referid}=1;
                    778: 	}
                    779:     }
                    780:     if ($token->[2]->{'name'}=~/^parameter_(0_)*hiddenresource$/) {
                    781: 	if ($token->[2]->{'value'}=~/^yes$/i) {
                    782: 	    $hiddenurl{$referid}=1;
                    783: 	}
                    784:     }
                    785: 
                    786: }
                    787: 
                    788: 
                    789: #
                    790: #  Parses a resource tag to produce the value to push into the
                    791: #  map_ids array.
                    792: # 
                    793: #
                    794: #  Information about the actual type of resource is provided by the file extension
                    795: #  of the uri (e.g. .problem, .sequence etc. etc.).
                    796: #
                    797: #  Parameters:
                    798: #    $token   - A token from HTML::TokeParser
                    799: #               This is an array that describes the most recently parsed HTML item.
                    800: #    $lpc     - Map nesting level (?)
                    801: #    $ispage  - True if this resource is encapsulated in a .page (assembled resourcde).
                    802: #    $uri     - URI of the enclosing resource.
1.7       raeburn   803: #    $code    - CODE for which resource is being parsed (CODEd assignments).
1.1       foxr      804: #    $hash    - Reference to the hash we are building.
                    805: #
                    806: # Returns:
                    807: #   Value of the id attribute of the tag.
                    808: #
                    809: # Note:
                    810: #   The token is an array that contains the following elements:
                    811: #   [0]   => 'S' indicating this is a start token
                    812: #   [1]   => 'resource'  indicating this tag is a <resource> tag.
                    813: #   [2]   => Hash of attribute =>value pairs.
                    814: #   [3]   => @(keys [2]).
                    815: #   [4]   => unused.
                    816: #
                    817: #   The attributes of the resourcde tag include:
                    818: #
                    819: #   id     - The resource id.
                    820: #   src    - The URI of the resource.
                    821: #   type   - The resource type (e.g. start and finish).
                    822: #   title  - The resource title.
                    823: #
                    824: 
                    825: sub parse_resource {
1.7       raeburn   826:     my ($token,$lpc,$ispage,$uri,$code,$hash) = @_;
1.1       foxr      827:     
                    828:     # I refuse to countenance code like this that has 
                    829:     # such a dirty side effect (and forcing this sub to be called within a loop).
                    830:     #
                    831:     #  if ($token->[2]->{'type'} eq 'zombie') { next; }
                    832:     #
                    833:     #  The original code both returns _and_ skips to the next pass of the >caller's<
                    834:     #  loop, that's just dirty.
                    835:     #
                    836: 
                    837:     # Zombie resources don't produce anything useful.
                    838: 
                    839:     if ($token->[2]->{'type'} eq 'zombie') {
                    840: 	return undef;
                    841:     }
                    842: 
                    843:     my $rid=$lpc.'.'.$token->[2]->{'id'}; # Resource id in hash is levelcounter.id-in-xml.
                    844: 
                    845:     # Save the hash element type and title:
                    846: 	    
                    847:     $hash->{'kind_'.$rid}='res';
                    848:     $hash->{'title_'.$rid}=$token->[2]->{'title'};
                    849: 
                    850:     # Get the version free URI for the resource.
                    851:     # If a 'version' attribute was supplied, and this resource's version 
                    852:     # information has not yet been stored, store it.
                    853:     #
                    854: 
                    855: 
                    856:     my $turi=&versiontrack($token->[2]->{'src'});
                    857:     if ($token->[2]->{'version'}) {
                    858: 	unless ($hash->{'version_'.$turi}) {
                    859: 
                    860: 	    #Where does the value of $1 below come from?
                    861: 	    #$1 for the regexps in versiontrack should have gone out of scope.
                    862: 	    #
                    863: 	    # I think this may be dead code since versiontrack ought to set
                    864: 	    # this hash element(?).
                    865: 	    #
                    866: 	    $hash->{'version_'.$turi}=$1;
                    867: 	}
                    868:     }
                    869:     # Pull out the title and do entity substitution on &colon
                    870:     # Q: Why no other entity substitutions?
                    871: 
                    872:     my $title=$token->[2]->{'title'};
                    873:     $title=~s/\&colon\;/\:/gs;
                    874: 
                    875: 
                    876: 
                    877:     # I think the point of all this code is to construct a final
                    878:     # URI that apache and its rewrite rules can use to
                    879:     # fetch the resource.   Thi s sonly necessary if the resource
                    880:     # is not a page.  If the resource is a page then it must be
                    881:     # assembled (at fetch time?).
                    882: 
                    883:     unless ($ispage) {
                    884: 	$turi=~/\.(\w+)$/;
                    885: 	my $embstyle=&Apache::loncommon::fileembstyle($1);
                    886: 	if ($token->[2]->{'external'} eq 'true') { # external
                    887: 	    $turi=~s/^https?\:\/\//\/adm\/wrapper\/ext\//;
                    888: 	} elsif ($turi=~/^\/*uploaded\//) { # uploaded
                    889: 	    if (($embstyle eq 'img') 
                    890: 		|| ($embstyle eq 'emb')
                    891: 		|| ($embstyle eq 'wrp')) {
                    892: 		$turi='/adm/wrapper'.$turi;
                    893: 	    } elsif ($embstyle eq 'ssi') {
                    894: 		#do nothing with these
                    895: 	    } elsif ($turi!~/\.(sequence|page)$/) {
                    896: 		$turi='/adm/coursedocs/showdoc'.$turi;
                    897: 	    }
                    898: 	} elsif ($turi=~/\S/) { # normal non-empty internal resource
                    899: 	    my $mapdir=$uri;
                    900: 	    $mapdir=~s/[^\/]+$//;
                    901: 	    $turi=&Apache::lonnet::hreflocation($mapdir,$turi);
                    902: 	    if (($embstyle eq 'img') 
                    903: 		|| ($embstyle eq 'emb')
                    904: 		|| ($embstyle eq 'wrp')) {
                    905: 		$turi='/adm/wrapper'.$turi;
                    906: 	    }
                    907: 	}
                    908:     }
                    909:     # Store reverse lookup, remove query string resource 'ids'_uri => resource id.
                    910:     # If the URI appears more than one time in the sequence, it's resourcde
                    911:     # id's are constructed as a comma spearated list.
                    912: 
                    913:     my $idsuri=$turi;
                    914:     $idsuri=~s/\?.+$//;
                    915:     if (defined($hash->{'ids_'.$idsuri})) {
                    916: 	$hash->{'ids_'.$idsuri}.=','.$rid;
                    917:     } else {
                    918: 	$hash->{'ids_'.$idsuri}=''.$rid;
                    919:     }
                    920:     
                    921: 
                    922: 
                    923:     if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard|viewclasslist)$/) {
                    924: 	$turi.='?register=1';
                    925:     }
                    926:     
                    927: 
                    928:     # resource id lookup:  'src'_resourc-di  => URI decorated with a query
                    929:     # parameter as above if necessary due to the resource type.
                    930:     
                    931:     $hash->{'src_'.$rid}=$turi;
                    932: 
                    933:     # Mark the external-ness of the resource:
                    934:     
                    935:     if ($token->[2]->{'external'} eq 'true') {
                    936: 	$hash->{'ext_'.$rid}='true:';
                    937:     } else {
                    938: 	$hash->{'ext_'.$rid}='false:';
                    939:     }
                    940: 
                    941:     # If the resource is a start/finish resource set those
                    942:     # entries in the has so that navigation knows where everything starts.
                    943:     #   If there is a malformed sequence that has no start or no finish
                    944:     # resource, should this be detected and errors thrown?  How would such a 
                    945:     # resource come into being other than being manually constructed by a person
                    946:     # and then uploaded?  Could that happen if an author decided a sequence was almost
                    947:     # right edited it by hand and then reuploaded it to 'fix it' but accidently cut the
                    948:     #  start or finish resources?
                    949:     #
                    950:     #  All resourcess also get a type_id => (start | finish | normal)    hash entr.
                    951:     #
                    952:     if ($token->[2]->{'type'}) {
                    953: 	$hash->{'type_'.$rid}=$token->[2]->{'type'};
                    954: 	if ($token->[2]->{'type'} eq 'start') {
                    955: 	    $hash->{'map_start_'.$uri}="$rid";
                    956: 	}
                    957: 	if ($token->[2]->{'type'} eq 'finish') {
                    958: 	    $hash->{'map_finish_'.$uri}="$rid";
                    959: 	}
                    960:     }  else {
                    961: 	$hash->{'type_'.$rid}='normal';
                    962:     }
                    963: 
                    964:     # Sequences end pages are constructed entities.  They require that the 
                    965:     # map that defines _them_ be loaded as well into the hash...with this resourcde
                    966:     # as the base of the nesting.
                    967:     # Resources like that are also marked with is_map_id => 1 entries.
                    968:     #
                    969:     
                    970:     if (($turi=~/\.sequence$/) ||
                    971: 	($turi=~/\.page$/)) {
1.3       foxr      972: 	$hash->{'is_map_'.$rid}='1'; # String in lonuserstate.
1.7       raeburn   973: 	&read_map($turi,$rid,$code,$hash);
1.1       foxr      974:     } 
                    975:     return $token->[2]->{'id'};
                    976: }
                    977: 
                    978: #  Links define how you are allowed to move from one resource to another.
                    979: #  They are the transition edges in the directed graph that a map is.
                    980: #  This sub takes informatino from a <link> tag and constructs the
                    981: #  navigation bits and pieces of a map.  There is no requirement that the
                    982: #  resources that are linke are already defined, however clearly the map is 
                    983: #  badly broken if they are not _eventually_ defined.
                    984: #
                    985: #  Note that links can be unconditional or conditional.
                    986: #
                    987: #  Parameters:
                    988: #     linkpc   - The link counter for this level of map nesting (this is 
                    989: #                reset to zero by read_map prior to starting to process
                    990: #                links for map).
                    991: #     lpc      - The map level ocounter (how deeply nested this map is in
                    992: #                the hierarchy of maps that are recursively read in.
                    993: #     to       - resource id (within the XML) of the target of the edge.
                    994: #     from     - resource id (within the XML) of the source of the edge.
                    995: #     condition- id of condition associated with the edge (also within the XML).
                    996: #     hash     - reference to the hash we are building.
                    997: 
                    998: #
                    999: 
                   1000: sub make_link {
                   1001:     my ($linkpc,$lpc,$to,$from,$condition, $hash) = @_;
                   1002:     
                   1003:     #  Compute fully qualified ids for the link, the 
                   1004:     # and from/to by prepending lpc.
                   1005:     #
                   1006: 
                   1007:     my $linkid=$lpc.'.'.$linkpc;
                   1008:     my $goesto=$lpc.'.'.$to;
                   1009:     my $comesfrom=$lpc.'.'.$from;
1.3       foxr     1010:     my $undercond='0';
1.1       foxr     1011: 
                   1012: 
                   1013:     # If there is a condition, qualify it with the level counter.
                   1014: 
                   1015:     if ($condition) {
                   1016: 	$undercond=$lpc.'.'.$condition;
                   1017:     }
                   1018: 
                   1019:     # Links are represnted by:
                   1020:     #  goesto_.fuullyqualifedlinkid => fully qualified to
                   1021:     #  comesfrom.fullyqualifiedlinkid => fully qualified from
                   1022:     #  undercond_.fullyqualifiedlinkid => fully qualified condition id.
                   1023: 
                   1024:     $hash->{'goesto_'.$linkid}=$goesto;
                   1025:     $hash->{'comesfrom_'.$linkid}=$comesfrom;
                   1026:     $hash->{'undercond_'.$linkid}=$undercond;
                   1027: 
                   1028:     # In addition:
                   1029:     #   to_.fully qualified from => comma separated list of 
                   1030:     #   link ids with that from.
                   1031:     # Similarly:
                   1032:     #   from_.fully qualified to => comma separated list of link ids`
                   1033:     #                               with that to.
                   1034:     #  That allows us given a resource id to know all edges that go to it
                   1035:     #  and leave from it.
                   1036:     #
                   1037: 
                   1038:     if (defined($hash->{'to_'.$comesfrom})) {
                   1039: 	$hash->{'to_'.$comesfrom}.=','.$linkid;
                   1040:     } else {
                   1041: 	$hash->{'to_'.$comesfrom}=''.$linkid;
                   1042:     }
                   1043:     if (defined($hash->{'from_'.$goesto})) {
                   1044: 	$hash->{'from_'.$goesto}.=','.$linkid;
                   1045:     } else {
                   1046: 	$hash->{'from_'.$goesto}=''.$linkid;
                   1047:     }
                   1048: }
                   1049: 
                   1050: # ------------------------------------------------------------------- Condition
                   1051: #
                   1052: #  Processes <condition> tags, storing sufficient information about them
                   1053: #  in the hash so that they can be evaluated and used to conditionalize
                   1054: #  what is presented to the student.
                   1055: #
                   1056: #  these can have the following attributes 
                   1057: #
                   1058: #    id    = A unique identifier of the condition within the map.
                   1059: #
                   1060: #    value = Is a perl script-let that, when evaluated in safe space
                   1061: #            determines whether or not the condition is true.
                   1062: #            Normally this takes the form of a test on an  Apache::lonnet::EXT call
                   1063: #            to find the value of variable associated with a resource in the
                   1064: #            map identified by a mapalias.
                   1065: #            Here's a fragment of XML code that illustrates this:
                   1066: #
                   1067: #           <param to="5" value="mainproblem" name="parameter_0_mapalias" type="string" />
                   1068: #           <resource src="" id="1" type="start" title="Start" />
                   1069: #           <resource src="/res/msu/albertel/b_and_c/p1.problem" id="5"  title="p1.problem" />
                   1070: #           <condition value="&EXT('user.resource.resource.0.tries','mainproblem')
                   1071: #           <2 " id="61" type="stop" />
                   1072: #           <link to="5" index="1" from="1" condition="61" />    
                   1073: #
                   1074: #           In this fragment:
                   1075: #             - The param tag establishes an alias to resource id 5 of 'mainproblem'.
                   1076: #             - The resource that is the start of the map is identified.
                   1077: #             - The resource tag identifies the resource associated with this tag
                   1078: #               and gives it the id 5.
                   1079: #             - The condition is true if the tries variable associated with mainproblem
                   1080: #               is less than 2 (that is the user has had more than 2 tries).
                   1081: #               The condition type is a stop condition which inhibits(?) the associated
                   1082: #               link if the condition  is false. 
                   1083: #             - The link to resource 5 from resource 1 is affected by this condition.    
                   1084: #            
                   1085: #    type  = Type of the condition. The type determines how the condition affects the
                   1086: #            link associated with it and is one of
                   1087: #            -  'force'
                   1088: #            -  'stop'
                   1089: #              anything else including not supplied..which treated as:
                   1090: #            - 'normal'.
                   1091: #            Presumably maps get created by the resource assembly tool and therefore
                   1092: #            illegal type values won't squirm their way into the XML.
                   1093: #   hash   - Reference to the hash we are trying to build up.
                   1094: #
                   1095: # Side effects:
                   1096: #   -  The kind_level-qualified-condition-id hash element is set to 'cond'.
                   1097: #   -  The condition text is pushed into the cond array and its element number is
                   1098: #      set in the condid_level-qualified-condition-id element of the hash.
                   1099: #   - The condition type is colon appneded to the cond array element for this condition.
                   1100: sub parse_condition {
                   1101:     my ($token, $lpc, $hash) = @_;
                   1102:     my $rid=$lpc.'.'.$token->[2]->{'id'};
                   1103:     
                   1104:     $hash->{'kind_'.$rid}='cond';
                   1105: 
                   1106:     my $condition = $token->[2]->{'value'};
                   1107:     $condition =~ s/[\n\r]+/ /gs;
                   1108:     push(@cond, $condition);
                   1109:     $hash->{'condid_'.$rid}=$#cond;
                   1110:     if ($token->[2]->{'type'}) {
                   1111: 	$cond[$#cond].=':'.$token->[2]->{'type'};
                   1112:     }  else {
                   1113: 	$cond[$#cond].=':normal';
                   1114:     }
                   1115: }
                   1116: 
                   1117: #
                   1118: #  Parse mapalias parameters.
                   1119: #  these are tags of the form:
                   1120: #  <param to="nn" 
                   1121: #         value="some-alias-for-resourceid-nn" 
                   1122: #         name="parameter_0_mapalias" 
                   1123: #         type="string" />
                   1124: #  A map alias is a textual name for a resource:
                   1125: #    - The to  attribute identifies the resource (this gets level qualified below)
                   1126: #    - The value attributes provides the alias string.
                   1127: #    - name must be of the regexp form: /^parameter_(0_)*mapalias$/
                   1128: #    - e.g. the string 'parameter_' followed by 0 or more "0_" strings
                   1129: #      terminating with the string 'mapalias'.
                   1130: #      Examples:
                   1131: #         'parameter_mapalias', 'parameter_0_mapalias', parameter_0_0_mapalias'
                   1132: #  Invalid to ids are silently ignored.
                   1133: #
                   1134: #  Parameters:
                   1135: #     token - The token array fromthe HMTML::TokeParser
                   1136: #     lpc   - The current map level counter.
                   1137: #     hash  - Reference to the hash that we are building.
                   1138: #
                   1139: sub parse_mapalias_param {
                   1140:     my ($token, $lpc, $hash) = @_;
                   1141: 
                   1142:     # Fully qualify the to value and ignore the alias if there is no
                   1143:     # corresponding resource.
                   1144: 
                   1145:     my $referid=$lpc.'.'.$token->[2]->{'to'};
                   1146:     return if (!exists($hash->{'src_'.$referid}));
                   1147: 
                   1148:     # If this is a valid mapalias parameter, 
                   1149:     # Append the target id to the count_mapalias element for that
                   1150:     # alias so that we can detect doubly defined aliases
                   1151:     # e.g.:
                   1152:     #  <param to="1" value="george" name="parameter_0_mapalias" type="string" />
                   1153:     #  <param to="2" value="george" name="parameter_0_mapalias" type="string" />
                   1154:     #
                   1155:     #  The example above is trivial but the case that's important has to do with
                   1156:     #  constructing a map that includes a nested map where the nested map may have
                   1157:     #  aliases that conflict with aliases established in the enclosing map.
                   1158:     #
                   1159:     # ...and create/update the hash mapalias entry to actually store the alias.
                   1160:     #
                   1161: 
                   1162:     if ($token->[2]->{'name'}=~/^parameter_(0_)*mapalias$/) {
                   1163: 	&count_mapalias($token->[2]->{'value'},$referid);
                   1164: 	$hash->{'mapalias_'.$token->[2]->{'value'}}=$referid;
                   1165:     }
                   1166: }
                   1167: 
                   1168: 
                   1169: #---------------------------------------------------------------------------------
                   1170: #
                   1171: #  Code to process the map file.
                   1172: 
                   1173: #  read a map file and add it to the hash.  Since a course map can contain resources
                   1174: #  that are themselves maps, read_map might be recursively called.
                   1175: #
                   1176: # Parameters:
                   1177: #   $uri         - URI of the course itself (not the map file).
                   1178: #   $parent_rid  - map number qualified id of the parent of the map being read.
                   1179: #                  For the top level course map this is 0.0.  For the first nested
                   1180: #                  map 1.n  where n is the id of the resource within the
1.7       raeburn  1181: #                  top level map and so on.
                   1182: #   $code        - CODE for which map is being read (CODEd assignments).
1.1       foxr     1183: #   $hash        - Reference to a hash that will become the big hash for the course
                   1184: #                  This hash is modified as per the map description.
                   1185: # Side-effects:
                   1186: #   $map_number - Will be  incremented.   This keeps track of the number of the map
                   1187: #                 we are currently working on (see parent_rid above, the number to the
                   1188: #                 left of the . in $parent_rid is the map number).
                   1189: #
                   1190: #  
                   1191: sub read_map {
1.7       raeburn  1192:     my ($uri, $parent_rid, $code, $hash) = @_;
1.1       foxr     1193: 
1.3       foxr     1194: 
1.1       foxr     1195:     # Check for duplication: A map may only be included once.
                   1196: 
                   1197:     if($hash->{'map_pc_' . $uri}) {
1.2       foxr     1198: 	throw Error::Simple('Duplicate map: ', $uri);
1.1       foxr     1199:     }
                   1200:     # count the map number and save it locally so that we don't lose it
                   1201:     # when we recurse.
                   1202: 
                   1203:     $map_number++;
                   1204:     my $lmap_no = $map_number;
                   1205: 
                   1206:     # save the map_pc and map_id elements of the hash for this map:
                   1207:     #  map_pc_uri is the map number of the map with that URI.
                   1208:     #  map_id_$lmap_no is the URI for this map level.
                   1209:     #
1.3       foxr     1210:     $hash->{'map_pc_' . $uri}     = "$lmap_no"; # string form in lonuserstate.
                   1211:     $hash->{'map_id_' . $lmap_no} = "$uri";
1.1       foxr     1212: 
                   1213:     # Create the path up to the top of the course.
                   1214:     # this is in 'map_hierarchy_mapno'  that's a comma separated path down to us
                   1215:     # in the hierarchy:
                   1216: 
                   1217:     if ($parent_rid =~/^(\d+).\d+$/) { 
                   1218: 	my $parent_no = $1;	       # Parent's map number.
                   1219: 	if (defined($hash->{'map_hierarchy_' . $parent_no})) {
                   1220: 	    $hash->{'map_hierarchy_' . $lmap_no} =
1.2       foxr     1221: 		$hash->{'map_hierarchy_' . $parent_no} . ',' . $parent_no;
1.1       foxr     1222: 	} else {
                   1223: 	    # Only 1 level deep ..nothing to append to:
                   1224: 
                   1225: 	    $hash->{'map_hierarchy_' . $lmap_no} = $parent_no;
                   1226: 	}
                   1227:     }
                   1228: 
                   1229:     # figure out the name of the map file we need to read.
                   1230:     # ensure that it is a .page or a .sequence as those are the only 
                   1231:     # sorts of files that make sense for this sub 
                   1232: 
                   1233:     my $filename = &Apache::lonnet::filelocation('', &append_version($uri, $hash));
1.3       foxr     1234: 
                   1235: 
1.1       foxr     1236:     my $ispage = ($filename =~/\.page$/);
1.2       foxr     1237:     unless ($ispage || ($filename =~ /\.sequence$/)) {
1.6       foxr     1238: 	&Apache::lonnet::logthis("invalid: $filename : $uri");
1.1       foxr     1239: 	throw Error::Simple(&mt("<br />Invalid map: <tt>[_1]</tt>", $filename));
                   1240:     }
                   1241: 
                   1242:     $filename =~ /\.(\w+)$/;
                   1243: 
1.2       foxr     1244:     $hash->{'map_type_'.$lmap_no}=$1;
1.1       foxr     1245: 
                   1246:     # Repcopy the file and get its contents...report errors if we can't
                   1247:    
1.3       foxr     1248:     my $contents = &Apache::lonnet::getfile($filename);
1.1       foxr     1249:     if($contents eq -1) {
                   1250:         throw Error::Simple(&mt('<br />Map not loaded: The file <tt>[_1]</tt> does not exist.',
                   1251: 				$filename));
                   1252:     }
                   1253:     # Now that we succesfully retrieved the file we can make our parsing passes over it:
                   1254:     # parsing is done in passes:
                   1255:     # 1. Parameters are parsed.
                   1256:     # 2. Resource, links and conditions are parsed.
                   1257:     #
                   1258:     # post processing takes care of the case where the sequence is random ordered
                   1259:     # or randomselected.
                   1260: 
                   1261:     # Parse the parameters,  This pass only cares about start tags for <param>
                   1262:     # tags.. this is because there is no body to a <param> tag.
                   1263:     #
                   1264: 
1.2       foxr     1265:     my $parser  = HTML::TokeParser->new(\$contents);
1.1       foxr     1266:     $parser->attr_encoded(1);	# Don't interpret entities in attributes (leave &xyz; alone).
                   1267: 
                   1268:     while (my $token = $parser->get_token()) {
                   1269: 	if (($token->[0] eq 'S') && ($token->[1] eq 'param')) { 
                   1270: 	    &parse_param($token, $map_number, $hash);
                   1271: 	}
                   1272:     }
                   1273: 
                   1274:     # ready for pass 2: Resource links and conditions.
                   1275:     # Note that if the map is random-ordered link tags are computed by randomizing
                   1276:     # resource order.  Furthermore, since conditions are set on links rather than
                   1277:     # resources, they are also not processed if random order is turned on.
                   1278:     #
                   1279: 
1.2       foxr     1280:     $parser = HTML::TokeParser->new(\$contents); # no way to reset the existing parser
1.1       foxr     1281:     $parser->attr_encoded(1);
                   1282: 
                   1283:     my $linkpc=0;
                   1284:     my $randomize = ($randomorder{$parent_rid} =~ /^yes$/i);
                   1285: 
                   1286:     my @map_ids;
                   1287:     while (my $token = $parser->get_token) {
                   1288: 	next if ($token->[0] ne 'S');
                   1289: 
                   1290: 	# Resource
                   1291: 
                   1292: 	if ($token->[1] eq 'resource') {
1.7       raeburn  1293: 	    my $resource_id = &parse_resource($token,$lmap_no,$ispage,$uri,$code,$hash);
1.1       foxr     1294: 	    if (defined $resource_id) {
                   1295: 		push(@map_ids, $resource_id); 
                   1296: 	    }
                   1297: 
                   1298:        # Link
                   1299: 
                   1300: 	} elsif ($token->[1] eq 'link' && !$randomize) {
1.2       foxr     1301: 	    &make_link(++$linkpc,$lmap_no,$token->[2]->{'to'},
1.1       foxr     1302: 		       $token->[2]->{'from'},
                   1303: 		       $token->[2]->{'condition'}, $hash); # note ..condition may be undefined.
                   1304: 
                   1305: 	# condition
                   1306: 
                   1307: 	} elsif ($token->[1] eq 'condition' && !$randomize) {
1.2       foxr     1308: 	    &parse_condition($token,$lmap_no, $hash);
1.1       foxr     1309: 	}
                   1310:     }
                   1311: 
                   1312:     #  This section handles random ordering by permuting the 
                   1313:     # IDs of the map according to the user's random seed.
                   1314:     # 
                   1315: 
                   1316:     if ($randomize) {
1.7       raeburn  1317: 	if (!&has_advanced_role($username, $userdomain) || $code) {
1.1       foxr     1318: 	    my $seed;
                   1319: 
                   1320: 	    # In the advanced role, the map's random seed
                   1321: 	    # parameter is used as the basis for computing the
                   1322: 	    # seed ... if it has been specified:
                   1323: 
                   1324: 	    if (defined($randompickseed{$parent_rid})) {
                   1325: 		$seed = $randompickseed{$parent_rid};
                   1326: 	    } else {
                   1327: 
                   1328: 		# Otherwise the parent's fully encoded symb is used.
                   1329: 
                   1330: 		my ($mapid,$resid)=split(/\./,$parent_rid);
                   1331: 		my $symb=
                   1332: 		    &Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},
                   1333: 						 $resid,$hash->{'src_'.$parent_rid});
                   1334: 		
                   1335: 		$seed = $symb;
                   1336: 	    }
                   1337: 
                   1338: 
1.6       foxr     1339: 	    my $rndseed=&Apache::lonnet::rndseed($seed, '', 
                   1340: 						 $userdomain, $username,
                   1341: 						 \%cenv);
                   1342: 						 
                   1343: 
1.1       foxr     1344: 	    &Apache::lonnet::setup_random_from_rndseed($rndseed);
                   1345: 
                   1346: 	    # Take the set of map ids we have decoded and permute them to a
                   1347: 	    # random order based on the seed set above. All of this is
                   1348: 	    # processing the randomorder parameter if it is set, not
                   1349: 	    # randompick.
                   1350: 
1.6       foxr     1351: 	    @map_ids=&Math::Random::random_permutation(@map_ids); 
1.1       foxr     1352: 	}
                   1353: 	my $from = shift(@map_ids);
1.2       foxr     1354: 	my $from_rid = $lmap_no.'.'.$from;
1.1       foxr     1355: 	$hash->{'map_start_'.$uri} = $from_rid;
                   1356: 	$hash->{'type_'.$from_rid}='start';
                   1357: 
                   1358: 	# Create links to reflect the random re-ordering done above.
                   1359: 	# In the code to process the map XML, we did not process links or conditions
                   1360: 	# if randomorder was set.  This means that for an instructor to choose
                   1361: 
                   1362: 	while (my $to = shift(@map_ids)) {
1.3       foxr     1363: 	    &make_link(++$linkpc,$lmap_no,$to,$from, 0, $hash);
1.2       foxr     1364: 	    my $to_rid =  $lmap_no.'.'.$to;
1.1       foxr     1365: 	    $hash->{'type_'.$to_rid}='normal';
                   1366: 	    $from = $to;
                   1367: 	    $from_rid = $to_rid;
                   1368: 	}
                   1369: 
                   1370: 	$hash->{'map_finish_'.$uri}= $from_rid;
                   1371: 	$hash->{'type_'.$from_rid}='finish';
                   1372:     }
                   1373: 
1.6       foxr     1374: 
1.1       foxr     1375:     #  The last parsing pass parses the <mapalias> tags that associate a name
                   1376:     #  with resource ids.
                   1377: 
                   1378:     $parser = HTML::TokeParser->new(\$contents);
                   1379:     $parser->attr_encoded(1);
                   1380: 
                   1381:     while (my $token = $parser->get_token) {
                   1382: 	next if ($token->[0] ne 'S');
                   1383: 	if ($token->[1] eq 'param') {
1.2       foxr     1384: 	    &parse_mapalias_param($token,$lmap_no, $hash);  
1.1       foxr     1385: 	} 
                   1386:     }
                   1387: 
                   1388: }
                   1389: 
                   1390: 
                   1391: #
                   1392: #  Load a map from file into a target hash.  This is done by first parsing the 
                   1393: #  map file into local hashes and then unrolling those hashes into the big hash.
                   1394: # 
                   1395: # Parameters:
                   1396: #
                   1397: #    $cnum       - number of course being read.
                   1398: #    $cdom       - Domain in which the course is evaluated.
                   1399: #    $uname      - Name of the user for whom the course is being read
                   1400: #    $udom       - Name of the domain of the user for whom the course is being read.
1.7       raeburn  1401: #    $code       - CODE for which course is being read (CODEd assignments)
1.1       foxr     1402: #    $target_hash- Reference to the target hash into which all of this is read.
                   1403: #                  Note tht some of the hash entries we need to build require knowledge of the
                   1404: #                  course URI.. these are expected to be filled in by the caller.
                   1405: #
                   1406: # Errors are logged to lonnet and are managed via the Perl structured exception package.
                   1407: #
                   1408: #  
                   1409: sub loadmap {
1.7       raeburn  1410:     my ($cnum, $cdom, $uname, $udom, $code, $target_hash) = @_;
1.3       foxr     1411: 
                   1412: 
1.1       foxr     1413: 
1.8       raeburn  1414:     # Clear the auxiliary hashes and the cond array.
1.1       foxr     1415: 
                   1416: 
                   1417:     %randompick     = ();
                   1418:     %randompickseed = ();
                   1419:     %encurl         = ();
                   1420:     %hiddenurl      = ();
1.2       foxr     1421:     %parmhash       = ();
1.4       foxr     1422:     @cond           = ('true:normal'); # Initial value for cond 0.
1.2       foxr     1423:     $retfrid        = '';
1.3       foxr     1424:     $username       = '';
                   1425:     $userdomain     = '';
                   1426:     %mapalias_cache = ();
                   1427:     %cenv           = ();
1.1       foxr     1428: 
1.2       foxr     1429:     
1.1       foxr     1430:     # 
                   1431: 
                   1432:     $username   = $uname;
                   1433:     $userdomain = $udom;
                   1434: 
1.6       foxr     1435:     $short_name = $cdom .'/' . $cnum;
1.3       foxr     1436:     my $retfurl;
1.1       foxr     1437: 
                   1438:     try {
                   1439: 
                   1440: 	
                   1441: 	# Get the information we need about the course.
1.6       foxr     1442:  	# Return without filling in anything if we can't get any info:
                   1443:  	
                   1444:  	%cenv = &Apache::lonnet::coursedescription($short_name,
                   1445:  						     {'freshen_cache' => 1,
                   1446:  						      'user'          => $uname}); 
                   1447:  
                   1448:  	unless ($cenv{'url'}) { 
                   1449:  	    &Apache::lonnet::logthis("lonmap::loadmap failed: $cnum/$cdom - did not get url");
                   1450:  	    return; 
                   1451:  	}
                   1452:  
                   1453:  	$course_id = $cdom . '_' . $cnum; # Long course id.
                   1454:  
                   1455:  	# Load the version information into the hash
                   1456:  
                   1457:  	
1.1       foxr     1458: 	&process_versions(\%cenv, $target_hash);
                   1459: 	
                   1460: 	
                   1461: 	# Figure out the map filename's URI, and set up some starting points for the map.
                   1462: 	
1.2       foxr     1463: 	my $course_uri = $cenv{'url'};
                   1464: 	my $map_uri    = &Apache::lonnet::clutter($course_uri);
1.1       foxr     1465: 	
                   1466: 	$target_hash->{'src_0.0'}            = &versiontrack($map_uri, $target_hash); 
                   1467: 	$target_hash->{'title_0.0'}          = &Apache::lonnet::metadata($course_uri, 'title');
1.3       foxr     1468: 	if(!defined $target_hash->{'title_0.0'}) {
                   1469: 	    $target_hash->{'title_0.0'} = '';
                   1470: 	}
1.2       foxr     1471: 	$target_hash->{'ids_'.$map_uri} = '0.0';
1.3       foxr     1472: 	$target_hash->{'is_map_0.0'}         = '1';
                   1473: 
                   1474: 	# In some places we need a username a domain and the courseid...store that
                   1475: 	# in the target hash in the context.xxxx keys:
                   1476: 
                   1477: 	$target_hash->{'context.username'} = $username;
                   1478: 	$target_hash->{'context.userdom'}  = $userdomain;
                   1479: 	$target_hash->{'context.courseid'} = $course_id;
                   1480: 
1.6       foxr     1481: 
1.7       raeburn  1482:         &read_map($course_uri, '0.0', $code, $target_hash);
1.1       foxr     1483: 
                   1484: 	# 
                   1485: 
1.2       foxr     1486: 	if (defined($target_hash->{'map_start_'.$map_uri})) {
1.1       foxr     1487: 
1.3       foxr     1488: 	    &traceroute('0',$target_hash->{'map_start_'.$course_uri},'&', 0, 0, $target_hash);
                   1489: 	    &accinit($course_uri, $short_name,  $target_hash);
1.2       foxr     1490: 	    &hiddenurls($target_hash);
                   1491: 	}
                   1492: 	my $errors = &get_mapalias_errors($target_hash);
                   1493: 	if ($errors ne "") {
                   1494: 	    throw Error::Simple("Map alias errors: ", $errors);
                   1495: 	}
                   1496: 
                   1497: 	# Put the versions in to src:
                   1498: 
                   1499: 	foreach my $key (keys(%$target_hash)) {
                   1500: 	    if ($key =~ /^src_/) {
                   1501: 		$target_hash->{$key} = 
                   1502: 		    &putinversion($target_hash->{$key}, $target_hash, $short_name);
                   1503: 	    } elsif ($key =~ /^(map_(?:start|finish|pc)_)(.*)/) {
                   1504: 		my ($type, $url) = ($1,$2);
                   1505: 		my $value = $target_hash->{$key};
                   1506: 		$target_hash->{$type.&putinversion($url, $target_hash, $short_name)}=$value;
                   1507: 	    }
1.1       foxr     1508: 	}
1.3       foxr     1509: 	#  Mark necrypted URLS.
                   1510: 
                   1511: 	foreach my $id (keys(%encurl)) {
                   1512: 	    $target_hash->{'encrypted_'.$id}=1;
                   1513: 	}
                   1514: 
                   1515: 	# Store first keys.
                   1516: 
                   1517: 	$target_hash->{'first_rid'}=$retfrid;
                   1518: 	my ($mapid,$resid)=split(/\./,$retfrid);
                   1519: 	$target_hash->{'first_mapurl'}=$target_hash->{'map_id_'.$mapid};
                   1520: 	my $symb=&Apache::lonnet::encode_symb($target_hash->{'map_id_'.$mapid},
                   1521: 					      $resid,
                   1522: 					      $target_hash->{'src_'.$retfrid});
                   1523: 	$retfurl=&add_get_param($target_hash->{'src_'.$retfrid},{ 'symb' => $symb });
                   1524: 	if ($target_hash->{'encrypted_'.$retfrid}) {
                   1525: 	    $retfurl=&Apache::lonenc::encrypted($retfurl,
                   1526: 						(&Apache::lonnet::allowed('adv') ne 'F'));
                   1527: 	}
                   1528: 	$target_hash->{'first_url'}=$retfurl;	
1.1       foxr     1529: 
                   1530: 	# Merge in the child hashes in case the caller wants that information as well.
                   1531: 
                   1532: 
1.2       foxr     1533: 	&merge_hash($target_hash, 'randompick', \%randompick);
                   1534: 	&merge_hash($target_hash, 'randompickseed', \%randompick);
                   1535: 	&merge_hash($target_hash, 'randomorder', \%randomorder);
                   1536: 	&merge_hash($target_hash, 'encurl', \%encurl);
                   1537: 	&merge_hash($target_hash, 'hiddenurl', \%hiddenurl);
                   1538: 	&merge_hash($target_hash, 'param', \%parmhash);
                   1539: 	&merge_conditions($target_hash);
1.1       foxr     1540:     }
                   1541:     otherwise {
                   1542: 	my $e = shift;
                   1543: 	&Apache::lonnet::logthis("lonmap::loadmap failed: " . $e->stringify());
                   1544:     }
                   1545: 
                   1546: }
                   1547: 
                   1548: 
                   1549: 1;
                   1550: 
                   1551: #
                   1552: #  Module initialization code:
1.3       foxr     1553: #  TODO:  Fix the pod docs below.
1.1       foxr     1554: 
                   1555: 1;
                   1556: __END__
                   1557: 
                   1558: =head1 NAME
                   1559: 
                   1560: Apache::lonmap - Construct a hash that represents a course (Big Hash).
                   1561: 
                   1562: =head1 SYNOPSIS
                   1563: 
                   1564: &Apache::lonmap::loadmap($filepath, \%target_hash);
                   1565: 
                   1566: =head1 INTRODUCTION
                   1567: 
                   1568: This module reads a course filename into a hash reference.  It's up to the caller
                   1569: to to things like decide the has should be tied to some external file and handle the locking
                   1570: if this file should be shared amongst several Apache children.
                   1571: 
                   1572: =head1 SUBROUTINES
                   1573: 
                   1574: =over
                   1575: 
                   1576: =item loadmap($filepath, $targethash)
                   1577: 
                   1578: 
                   1579: Reads the map file into a target hash.
                   1580: 
                   1581: =over
                   1582: 
                   1583: =item $filepath - The path to the map file to read.
                   1584: 
                   1585: =item $targethash - A reference to hash into which the course is read.
                   1586: 
                   1587: =back
                   1588: 
                   1589: =item process_versions($cenv, $hash)
                   1590: 
                   1591: Makes hash entries for each version of a course described by a course environment
                   1592: returned from Apache::lonnet::coursedescription.
                   1593: 
                   1594: =over
                   1595: 
                   1596: =item $cenv - Reference to the environment hash returned by Apache::lonnet::coursedescription
                   1597: 
                   1598: =item $hash - Hash to be filled in with 'version_xxx' entries as per the big hash.
                   1599: 
                   1600: =back
                   1601: 
                   1602: =back
                   1603:  
                   1604: 
                   1605: =cut

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