Annotation of loncom/lonmap.pm, revision 1.2

1.1       foxr        1: # The LearningOnline Network
                      2: #
                      3: #  Read maps into a 'big hash'.
                      4: #
1.2     ! foxr        5: # $Id: lonmap.pm,v 1.1 2011/09/07 10:58:36 foxr 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: 
                     31: package lonmap;
                     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;
                     43: 
                     44: #------------- File scoped variables:
                     45: 
                     46: my $map_number = 1;		# keep track of maps within the course.
                     47: my $course_id;     		# Will be the id of the course being read in.
                     48: 
                     49: #
                     50: # The variables below are auxiliary hashes.  They will be tacked onto the
                     51: # big hash though currently not used by clients.. you never know about later.
                     52: #
                     53: 
                     54: my %randompick;
                     55: my %randompickseed;
                     56: my %randomorder;
                     57: my %encurl;
                     58: my %hiddenurl;
1.2     ! foxr       59: my %parmhash;
1.1       foxr       60: my @cond;			# Array of conditions.
1.2     ! foxr       61: my $retfrid;
1.1       foxr       62: #
                     63: #  Other stuff we make global (sigh) so that it does not need
                     64: #  to be passed around all the time:
                     65: #
                     66: 
                     67: my $username;			# User for whom the map is being read.
                     68: my $userdomain;  		# Domain the user lives in.
                     69: my %mapalias_cache;		# Keeps track of map aliases -> resources detects duplicates.
                     70: 
                     71: #------------- Executable code: 
                     72: 
                     73: 
                     74: #----------------------------------------------------------------
                     75: #
                     76: #  General utilities:
                     77: 
                     78: 
                     79: #
                     80: #  I _think_ this does common sub-expression simplification and 
                     81: #  optimization for condition strings...based on common pattern matching.
                     82: # Parameters:
                     83: #    expression - the condition expression string.
                     84: # Returns:
                     85: #    The optimized expression if an optimization could be found.
                     86: #
                     87: # NOTE:
                     88: #   Added repetetive optimization..it's possible that an
                     89: #   optimization results in an expression that can be recognized further in
                     90: #   a subsequent optimization pass:
                     91: #
                     92: 
                     93: sub simplify {
                     94:     my $expression=shift;
                     95:     my $prior = '';		# This is safe as a null expression is pretty optimal.
                     96:     
                     97:     while ($prior ne $expression) {
                     98: 	$prior = $expression;	# Stop when the substitutions below do nothing.
                     99: # (0&1) = 1
                    100: 	$expression=~s/\(0\&([_\.\d]+)\)/$1/g;
                    101: # (8)=8
                    102: 	$expression=~s/\(([_\.\d]+)\)/$1/g;
                    103: # 8&8=8
                    104: 	$expression=~s/([^_\.\d])([_\.\d]+)\&\2([^_\.\d])/$1$2$3/g;
                    105: # 8|8=8
                    106: 	$expression=~s/([^_\.\d])([_\.\d]+)(?:\|\2)+([^_\.\d])/$1$2$3/g;
                    107: # (5&3)&4=5&3&4
                    108: 	$expression=~s/\(([_\.\d]+)((?:\&[_\.\d]+)+)\)\&([_\.\d]+[^_\.\d])/$1$2\&$3/g;
                    109: # (((5&3)|(4&6)))=((5&3)|(4&6))
                    110: 	$expression=~
                    111: 	    s/\((\(\([_\.\d]+(?:\&[_\.\d]+)*\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+\))\)/$1/g;
                    112: # ((5&3)|(4&6))|(1&2)=(5&3)|(4&6)|(1&2)
                    113: 	$expression=~
                    114: 	    s/\((\([_\.\d]+(?:\&[_\.\d]+)*\))((?:\|\([_\.\d]+(?:\&[_\.\d]+)*\))+)\)\|(\([_\.\d]+(?:\&[_\.\d]+)*\))/\($1$2\|$3\)/g;
                    115:     }
                    116:     return $expression;
                    117: }
                    118:     
                    119: 
                    120: #
                    121: #  Merge the conditions into the big hash
                    122: #  these will result in hash entries of the form:
                    123: #   'condition.n'  where 'n' is the array index of the condition in the
                    124: #   @cond array above.
                    125: #
                    126: #  Parameters:
                    127: #    $hash - big hashthat's being built up.
                    128: #
                    129: sub merge_conditions {
                    130:     my $hash = shift;
                    131: 
1.2     ! foxr      132:     for (my $i = 0; $i < scalar(@cond); $i++) {
1.1       foxr      133: 	$hash->{'condition' . '.' . $i} = $cond[$i];
                    134:     }
                    135: }
                    136: 
                    137: # Merge the contents of a 'child hash' into a parent hash hanging it off another key.
                    138: # This is _not_ done by hanging a reference to the child hash as the parent may be
                    139: # bound to a GDBM file e.g. and shared by more than one process ..and references are
                    140: # pretty clearly not going to work across process boundaries.
                    141: #
                    142: # Parameters:
                    143: #   $parent  - The hash to which the child will be merged (reference)
                    144: #   $key     - The key in the parent hash on which the child elements will be hung.
                    145: #              given a key named $childkey the final parent hash entry will be
                    146: #              $parent . '.' $childkey
                    147: #  $child    - The hash whose contents we merge into the parent (reference)
                    148: #
                    149: sub merge_hash {
                    150:     my ($parent, $key, $child) = @_;
                    151: 
                    152:     foreach my $childkey (keys (%$child)) {
                    153: 	$parent->{$key . '.' . $childkey} = $child->{$childkey};
                    154:     }
                    155: }
                    156: 
                    157: #----------------------------------------------------------------------------------
                    158: #
                    159: #   Code to keep track of map aliases and to determine if there are doubly 
                    160: #   defined aliases.
                    161: #
                    162: 
                    163: #
                    164: #  Maintains the mapalias hash.  This is a hash of arrays.  Each array
                    165: #  is indexed by the alias and contains the set of resource ids pointed to by that
                    166: #  alias.  In an ideal world, there will only be one element in each array.
                    167: #  The point of this, however is to determine which aliases might be doubley defined
                    168: #  due to map nesting e.g.
                    169: #
                    170: #  Parameters:
                    171: #    $value   - Alias name.
                    172: #    $resid   - Resource id pointed to by the alias.
                    173: #
                    174: #    
                    175: sub count_mapalias {
                    176:     my ($value,$resid) = @_;
                    177:     push(@{ $mapalias_cache{$value} }, $resid);
                    178: }
                    179: #
                    180: #  Looks at each key in the mapalias hash and, for each case where an
                    181: #  alias points to more than one value adds an error text to the
                    182: #  result string.'
                    183: #
                    184: #  Parameters:
1.2     ! foxr      185: #     hash - Reference to the hash we are trying t build up.
1.1       foxr      186: #  Implicit inputs
                    187: #     %mapalias - a hash that is indexed by map aliases and contains for each key
                    188: #                 an array of the resource id's the alias 'points to'.
                    189: # Returns:
                    190: #    A hopefully empty string of messages that descsribe the aliases that have more
                    191: #    than one value.  This string is formatted like an html list.
                    192: #
                    193: #
                    194: sub get_mapalias_errors {
1.2     ! foxr      195:     my $hash = shift;
1.1       foxr      196:     my $error_text;
                    197:     foreach my $mapalias (sort(keys(%mapalias_cache))) {
                    198: 	next if (scalar(@{ $mapalias_cache{$mapalias} } ) == 1);
                    199: 	my $count;
                    200: 	my $which =
                    201: 	    join('</li><li>', 
                    202: 		 map {
                    203: 		     my $id = $_;
1.2     ! foxr      204: 		     if (exists($hash->{'src_'.$id})) {
1.1       foxr      205: 			 $count++;
                    206: 		     }
                    207: 		     my ($mapid) = split(/\./,$id);
                    208: 		     &mt('Resource "[_1]" <br /> in Map "[_2]"',
1.2     ! foxr      209: 			 $hash->{'title_'.$id},
        !           210: 			 $hash->{'title_'.$hash->{'ids_'.$hash->{'map_id_'.$mapid}}});
1.1       foxr      211: 		 } (@{ $mapalias_cache{$mapalias} }));
                    212: 	next if ($count < 2);
                    213: 	$error_text .= '<div class="LC_error">'.
                    214: 	    &mt('Error: Found the mapalias "[_1]" defined multiple times.',
                    215: 		$mapalias).
                    216: 		'</div><ul><li>'.$which.'</li></ul>';
                    217:     }
                    218:     &clear_mapalias_count();
                    219:     return $error_text;
                    220: }
                    221: #
                    222: #   Clears the map aliase hash.
                    223: #
                    224: sub clear_mapalias_count {
                    225:     undef(%mapalias_cache);
                    226: }
                    227: 
                    228: #----------------------------------------------------------------
                    229: #
                    230: #  Code dealing with resource versions.
                    231: #
                    232: 
                    233: #
1.2     ! foxr      234: #  Put a version into a src element of a hash or url:
        !           235: #
        !           236: #  Parameters:
        !           237: #     uri - URI into which the version must be added.
        !           238: #    hash - Reference to the hash being built up.
        !           239: #    short- Short coursename.
        !           240: #
        !           241: 
        !           242: sub putinversion {
        !           243:     my ($uri, $hash, $short) = @_;
        !           244:     my $key=$short.'_'.&Apache::lonnet::clutter($uri);
        !           245:     if ($hash->{'version_'.$uri}) {
        !           246: 	my $version=$hash->{'version_'.$uri};
        !           247: 	if ($version eq 'mostrecent') { return $uri; }
        !           248: 	if ($version eq &Apache::lonnet::getversion(
        !           249: 			&Apache::lonnet::filelocation('',$uri))) 
        !           250: 	             { return $uri; }
        !           251: 	$uri=~s/\.(\w+)$/\.$version\.$1/;
        !           252:     }
        !           253:     &Apache::lonnet::do_cache_new('courseresversion',$key,&Apache::lonnet::declutter($uri),600);
        !           254:     return $uri;
        !           255: }
        !           256: 
        !           257: 
        !           258: #
1.1       foxr      259: #  Create hash entries for each version of the course.
                    260: # Parameters:
                    261: #   $cenv    - Reference to a course environment from lonnet::coursedescription.
                    262: #   $hash    - Reference to a hash that will be populated.
                    263: 
                    264: #
                    265: sub process_versions {
                    266:     my ($cenv, $hash) = @_;
                    267: 
                    268:     
                    269:     my %versions = &Apache::lonnet::dump('resourceversions',
                    270: 					 $cenv->{'domain'},
                    271: 					 $cenv->{'num'});
                    272: 
                    273:     foreach my $ver (keys (%versions)) {
                    274: 	if ($ver =~/^error\:/) { # lonc/lond transaction failed.
                    275: 	    throw Error::Simple('lonc/lond returned error: ' . $ver);
                    276: 	}
                    277: 	$hash->{'version_'.$ver} = $versions{$ver};
                    278:     }
                    279: }
                    280: 
                    281: #
                    282: #  Generate text for a version discrepancy error:
                    283: # Parameters:
                    284: #  $uri   - URI of the resource.
                    285: #  $used  - Version used.
                    286: #  $unused - Veresion of duplicate.
                    287: #
                    288: sub versionerror {
                    289:     my ($uri, $used, $unused) = @_;
                    290:     my ($uri,$usedversion,$unusedversion)=@_;
                    291:     return '<br />'.
                    292: 	&mt('Version discrepancy: resource [_1] included in both version [_2] and version [_3]. Using version [_2].',
                    293: 	    $uri,$used,$unused).'<br />';
                    294: 
                    295: }
                    296: 
                    297: #  Removes the version number from a URI and returns the resulting
                    298: #  URI (e.g. mumbly.version.stuff => mumbly.stuff).
                    299: #
                    300: #   If the URI has not been seen with a version before the
                    301: #   hash{'version_'.resultingURI} is set to the  version number.
                    302: #   If the hash has already been seen, but differs then
                    303: #   an error is raised.
                    304: #
                    305: # Parameters:
                    306: #   $uri  -  potentially with a version.
                    307: #   $hash -  reference to a hash to fill in. 
                    308: # Returns:
                    309: #   URI with the version cut out.
                    310: #
                    311: sub vesiontrack {
                    312:     my ($uri, $hash) = @_;
                    313: 
                    314: 
                    315:     if ($uri=~/\.(\d+)\.\w+$/) { # URI like *.n.text it's version 'n'
                    316: 	my $version=$1;
                    317: 	$uri=~s/\.\d+\.(\w+)$/\.$1/; # elide the version.
                    318:         unless ($hash->{'version_'.$uri}) {
                    319: 	    $hash->{'version_'.$uri}=$version;
                    320: 	} elsif ($version!=$hash->{'version_'.$uri}) {
1.2     ! foxr      321: 	    throw Error::Simple(&versionerror($uri, $hash->{'version_'.$uri}, $version));
1.1       foxr      322:         }
                    323:     }
                    324:     return $uri;
                    325: }
                    326: #
                    327: #  Appends the version of a resource to its uri and also caches the 
                    328: #  URI (contents?) on the local server
                    329: #
                    330: #  Parameters:
                    331: #     $uri   - URI of the course (without version informatino.
                    332: #     $hash  - What we have of  the big hash.
                    333: #
                    334: # Side-Effects:
                    335: #   The URI is cached by memcached.
                    336: #
                    337: # Returns:
                    338: #    The version appended URI.
                    339: #
                    340: sub append_version {
                    341:     my ($uri, $hash) = @_;
                    342: 
                    343:     # Create the key for the cache entry.
                    344: 
                    345:     my $key = $course_id . '_' . &Apache::lonnet::clutter($uri);
                    346: 
                    347:     # If there is a version it will already be  in the hash:
                    348: 
                    349:     if ($hash->{'version_' . $uri}) {
                    350: 	my $version = $hash->{'version_' . $uri};
                    351: 	if ($version eq 'mostrecent') {
                    352: 	    return $uri;     # Most recent version does not require decoration (or caching?).
                    353: 	}
                    354: 	if ($version eq 
                    355: 	    &Apache::lonnet::getversion(&Apache::lonnet::filelocation('', $uri))) {
                    356: 	    return $uri;	# version matches the most recent file version?
                    357: 	}
                    358: 	$uri =~ s/\.(\w+)$/\.$version\.$1/; # insert the versino prior to the last .word.
                    359:     }
                    360:  
                    361:    # cache the version:
                    362: 
                    363:    &Apache::lonnet::do_cache_new('courseresversion', $key, 
                    364: 				 &Apache::lonnet::declutter($uri), 600);
                    365: 
                    366:     return $uri;
                    367: 
                    368: }
                    369: #--------------------------------------------------------------------------------
                    370: # Post processing subs:
                    371: sub hiddenurls {
                    372:     my $hash = shift;
                    373: 
                    374:     my $randomoutentry='';
                    375:     foreach my $rid (keys %randompick) {
                    376:         my $rndpick=$randompick{$rid};
                    377:         my $mpc=$hash->{'map_pc_'.$hash->{'src_'.$rid}};
                    378: # ------------------------------------------- put existing resources into array
                    379:         my @currentrids=();
                    380:         foreach my $key (sort(keys(%$hash))) {
                    381: 	    if ($key=~/^src_($mpc\.\d+)/) {
                    382: 		if ($hash->{'src_'.$1}) { push @currentrids, $1; }
                    383:             }
                    384:         }
                    385: 	# rids are number.number and we want to numercially sort on 
                    386:         # the second number
                    387: 	@currentrids=sort {
                    388: 	    my (undef,$aid)=split(/\./,$a);
                    389: 	    my (undef,$bid)=split(/\./,$b);
                    390: 	    $aid <=> $bid;
                    391: 	} @currentrids;
                    392:         next if ($#currentrids<$rndpick);
                    393: # -------------------------------- randomly eliminate the ones that should stay
                    394: 	my (undef,$id)=split(/\./,$rid);
                    395:         if ($randompickseed{$rid}) { $id=$randompickseed{$rid}; }
                    396: 	my $rndseed=&Apache::lonnet::rndseed($id); # use id instead of symb
                    397: 	&Apache::lonnet::setup_random_from_rndseed($rndseed);
                    398: 	my @whichids=&Math::Random::random_permuted_index($#currentrids+1);
                    399:         for (my $i=1;$i<=$rndpick;$i++) { $currentrids[$whichids[$i]]=''; }
                    400: 	#&Apache::lonnet::logthis("$id,$rndseed,".join(':',@whichids));
                    401: # -------------------------------------------------------- delete the leftovers
                    402:         for (my $k=0; $k<=$#currentrids; $k++) {
                    403:             if ($currentrids[$k]) {
                    404: 		$hash->{'randomout_'.$currentrids[$k]}=1;
                    405:                 my ($mapid,$resid)=split(/\./,$currentrids[$k]);
                    406:                 $randomoutentry.='&'.
                    407: 		    &Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},
                    408: 						 $resid,
                    409: 						 $hash->{'src_'.$currentrids[$k]}
                    410: 						 ).'&';
                    411:             }
                    412:         }
                    413:     }
                    414: # ------------------------------ take care of explicitly hidden urls or folders
                    415:     foreach my $rid (keys %hiddenurl) {
                    416: 	$hash->{'randomout_'.$rid}=1;
                    417: 	my ($mapid,$resid)=split(/\./,$rid);
                    418: 	$randomoutentry.='&'.
                    419: 	    &Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},$resid,
                    420: 					 $hash->{'src_'.$rid}).'&';
                    421:     }
                    422: # --------------------------------------- add randomout to the hash.
                    423:     if ($randomoutentry) {
                    424: 	$hash->{'acc.randomout'} = $randomoutentry;
                    425: 
                    426:     }
                    427: }
                    428: 
                    429: #
                    430: # It's not so clear to me what this sub does.
                    431: #
                    432: #  Parameters
                    433: #     uri   - URI from the course description hash.
                    434: #     short - Course short name.
                    435: #     fn    - Course filename.
                    436: #     hash  - Reference to the big hash as filled in so far
                    437: #       
                    438: 
                    439: sub accinit {
1.2     ! foxr      440:     my ($uri, $short, $fn, $hash)=@_;
1.1       foxr      441:     my %acchash=();
                    442:     my %captured=();
                    443:     my $condcounter=0;
                    444:     $acchash{'acc.cond.'.$short.'.0'}=0;
                    445: 
                    446:     # This loop is only interested in conditions and 
                    447:     # parameters in the big hash:
                    448: 
                    449:     foreach my $key (keys(%$hash)) {
                    450: 
                    451: 	# conditions:
                    452: 
                    453: 	if ($key=~/^conditions/) {
                    454: 	    my $expr=$hash->{$key};
                    455: 
                    456: 	    # try to find and factor out common sub-expressions
                    457: 	    # Any subexpression that is found is simplified, removed from
                    458: 	    # the original condition expression and the simplified sub-expression
                    459: 	    # substituted back in to the epxression..I'm not actually convinced this
                    460: 	    # factors anything out...but instead maybe simplifies common factors(?)
                    461: 
                    462: 	    foreach my $sub ($expr=~m/(\(\([_\.\d]+(?:\&[_\.\d]+)+\)(?:\|\([_\.\d]+(?:\&[_\.\d]+)+\))+\))/g) {
                    463: 		my $orig=$sub;
                    464: 
                    465: 		my ($factor) = ($sub=~/\(\(([_\.\d]+\&(:?[_\.\d]+\&)*)(?:[_\.\d]+\&*)+\)(?:\|\(\1(?:[_\.\d]+\&*)+\))+\)/);
                    466: 		next if (!defined($factor));
                    467: 
                    468: 		$sub=~s/\Q$factor\E//g;
                    469: 		$sub=~s/^\(/\($factor\(/;
                    470: 		$sub.=')';
                    471: 		$sub=simplify($sub);
                    472: 		$expr=~s/\Q$orig\E/$sub/;
                    473: 	    }
                    474: 	    $hash->{$key}=$expr;
                    475: 
                    476:            # If not yet seen, record in acchash and that we've seen it.
                    477: 
                    478: 	    unless (defined($captured{$expr})) {
                    479: 		$condcounter++;
                    480: 		$captured{$expr}=$condcounter;
                    481: 		$acchash{'acc.cond.'.$short.'.'.$condcounter}=$expr;
                    482: 	    } 
                    483:         # Parameters:
                    484: 
                    485: 	} elsif ($key=~/^param_(\d+)\.(\d+)/) {
                    486: 	    my $prefix=&Apache::lonnet::encode_symb($hash->{'map_id_'.$1},$2,
                    487: 						    $hash->{'src_'.$1.'.'.$2});
                    488: 	    foreach my $param (split(/\&/,$hash->{$key})) {
                    489: 		my ($typename,$value)=split(/\=/,$param);
                    490: 		my ($type,$name)=split(/\:/,$typename);
                    491: 		$parmhash{$prefix.'.'.&unescape($name)}=
                    492: 		    &unescape($value);
                    493: 		$parmhash{$prefix.'.'.&unescape($name).'.type'}=
                    494: 		    &unescape($type);
                    495: 	    }
                    496: 	}
                    497:     }
                    498:     # This loop only processes id entries in the big hash.
                    499: 
                    500:     foreach my $key (keys(%$hash)) {
                    501: 	if ($key=~/^ids/) {
                    502: 	    foreach my $resid (split(/\,/,$hash->{$key})) {
                    503: 		my $uri=$hash->{'src_'.$resid};
                    504: 		my ($uripath,$urifile) =
                    505: 		    &Apache::lonnet::split_uri_for_cond($uri);
                    506: 		if ($uripath) {
                    507: 		    my $uricond='0';
                    508: 		    if (defined($hash->{'conditions_'.$resid})) {
                    509: 			$uricond=$captured{$hash->{'conditions_'.$resid}};
                    510: 		    }
                    511: 		    if (defined($acchash{'acc.res.'.$short.'.'.$uripath})) {
                    512: 			if ($acchash{'acc.res.'.$short.'.'.$uripath}=~
                    513: 			    /(\&\Q$urifile\E\:[^\&]*)/) {
                    514: 			    my $replace=$1;
                    515: 			    my $regexp=$replace;
                    516: 			    #$regexp=~s/\|/\\\|/g;
                    517: 			    $acchash{'acc.res.'.$short.'.'.$uripath} =~
                    518: 				s/\Q$regexp\E/$replace\|$uricond/;
                    519: 			} else {
                    520: 			    $acchash{'acc.res.'.$short.'.'.$uripath}.=
                    521: 				$urifile.':'.$uricond.'&';
                    522: 			}
                    523: 		    } else {
                    524: 			$acchash{'acc.res.'.$short.'.'.$uripath}=
                    525: 			    '&'.$urifile.':'.$uricond.'&';
                    526: 		    }
                    527: 		} 
                    528: 	    }
                    529:         }
                    530:     }
                    531:     $acchash{'acc.res.'.$short.'.'}='&:0&';
                    532:     my $courseuri=$uri;
                    533:     $courseuri=~s/^\/res\///;
                    534:     my $regexp = 1;
                    535:  
                    536:     &merge_hash($hash, '', \%acchash); # there's already an acc prefix in the hash keys.
                    537: 
                    538: 
                    539: }
                    540: 
                    541: 
                    542: #
                    543: #  Traces a route recursively through the map after it has been loaded
                    544: #  (I believe this really visits each resource that is reachable fromt he
                    545: #  start top node.
                    546: #
                    547: #  - Marks hidden resources as hidden.
                    548: #  - Marks which resource URL's must be encrypted.
                    549: #  - Figures out (if necessary) the first resource in the map.
                    550: #  - Further builds the chunks of the big hash that define how 
                    551: #    conditions work
                    552: #
                    553: #  Note that the tracing strategy won't visit resources that are not linked to
                    554: #  anything or islands in the map (groups of resources that form a path but are not
                    555: #  linked in to the path that can be traced from the start resource...but that's ok
                    556: #  because by definition, those resources are not reachable by users of the course.
                    557: #
                    558: # Parameters:
                    559: #   sofar    - _URI of the prior entry or 0 if this is the top.
                    560: #   rid      - URI of the resource to visit.
                    561: #   beenhere - list of resources (each resource enclosed by &'s) that have
                    562: #              already been visited.
                    563: #   encflag  - If true the resource that resulted in a recursive call to us
                    564: #              has an encoded URL (which means contained resources should too). 
                    565: #   hdnflag  - If true,the resource that resulted in a recursive call to us
                    566: #              was hidden (which means contained resources should be hidden too).
                    567: #   hash     - Reference to the hash we are traversing.
                    568: # Returns
                    569: #    new value indicating how far the map has been traversed (the sofar).
                    570: #
                    571: sub traceroute {
1.2     ! foxr      572:     my ($sofar, $rid, $beenhere, $encflag, $hdnflag, $hash)=@_;
1.1       foxr      573:     my $newsofar=$sofar=simplify($sofar);
                    574: 
                    575:     unless ($beenhere=~/\&\Q$rid\E\&/) {
                    576: 	$beenhere.=$rid.'&';  
                    577: 	my ($mapid,$resid)=split(/\./,$rid);
                    578: 	my $symb=&Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},$resid,
                    579: 					      $hash->{'src_'.$rid});
                    580: 	my $hidden=&Apache::lonnet::EXT('resource.0.hiddenresource',$symb);
                    581: 
                    582: 	if ($hdnflag || lc($hidden) eq 'yes') {
                    583: 	    $hiddenurl{$rid}=1;
                    584: 	}
                    585: 	if (!$hdnflag && lc($hidden) eq 'no') {
                    586: 	    delete($hiddenurl{$rid});
                    587: 	}
                    588: 
                    589: 	my $encrypt=&Apache::lonnet::EXT('resource.0.encrypturl',$symb);
                    590: 	if ($encflag || lc($encrypt) eq 'yes') { $encurl{$rid}=1; }
                    591: 
                    592: 	if (($retfrid eq '') && ($hash->{'src_'.$rid})
                    593: 	    && ($hash->{'src_'.$rid}!~/\.sequence$/)) {
                    594: 	    $retfrid=$rid;
                    595: 	}
                    596: 
                    597: 	if (defined($hash->{'conditions_'.$rid})) {
                    598: 	    $hash->{'conditions_'.$rid}=simplify(
                    599:            '('.$hash->{'conditions_'.$rid}.')|('.$sofar.')');
                    600: 	} else {
                    601: 	    $hash->{'conditions_'.$rid}=$sofar;
                    602: 	}
                    603: 
                    604: 	# if the expression is just the 0th condition keep it
                    605: 	# otherwise leave a pointer to this condition expression
                    606: 
                    607: 	$newsofar = ($sofar eq '0') ? $sofar : '_'.$rid;
                    608: 
                    609: 	# Recurse if the resource is a map:
                    610: 
                    611: 	if (defined($hash->{'is_map_'.$rid})) {
                    612: 	    if (defined($hash->{'map_start_'.$hash->{'src_'.$rid}})) {
                    613: 		$sofar=$newsofar=
                    614: 		    &traceroute($sofar,
                    615: 				$hash->{'map_start_'.$hash->{'src_'.$rid}},
                    616: 				$beenhere,
                    617: 				$encflag || $encurl{$rid},
                    618: 				$hdnflag || $hiddenurl{$rid});
                    619: 	    }
                    620: 	}
                    621: 
                    622: 	# Processes  links to this resource:
                    623: 	#  - verify the existence of any conditionals on the link to here.
                    624: 	#  - Recurse to any resources linked to us.
                    625: 	#
                    626: 	if (defined($hash->{'to_'.$rid})) {
                    627: 	    foreach my $id (split(/\,/,$hash->{'to_'.$rid})) {
                    628: 		my $further=$sofar;
                    629: 		#
                    630: 		# If there's a condition associated with this link be sure
                    631: 		# it's been defined else that's an error:
                    632: 		#
                    633:                 if ($hash->{'undercond_'.$id}) {
                    634: 		    if (defined($hash->{'condid_'.$hash->{'undercond_'.$id}})) {
                    635: 			$further=simplify('('.'_'.$rid.')&('.
                    636: 					  $hash->{'condid_'.$hash->{'undercond_'.$id}}.')');
                    637: 		    } else {
1.2     ! foxr      638: 			my $errtext.=&mt('<br />Undefined condition ID: [_1]',$hash->{'undercond_'.$id});
1.1       foxr      639: 			throw Error::Simple($errtext);
                    640: 		    }
                    641:                 }
                    642: 		#  Recurse to resoruces that have to's to us.
                    643:                 $newsofar=&traceroute($further,$hash->{'goesto_'.$id},$beenhere,
                    644: 				      $encflag,$hdnflag);
                    645: 	    }
                    646: 	}
                    647:     }
                    648:     return $newsofar;
                    649: }
                    650: 
                    651: 
                    652: #---------------------------------------------------------------------------------
                    653: #
                    654: #  Map parsing code:
                    655: #
                    656: 
                    657: # 
                    658: #  Parse the <param> tag.  for most parameters, the only action is to define/extend
                    659: #  a has entry for {'param_{refid}'} where refid is the resource the parameter is
                    660: #  attached to and the value built up is an & separated list of parameters of the form:
                    661: #  type:part.name=value
                    662: #
                    663: #   In addition there is special case code for:
                    664: #   - randompick
                    665: #   - randompickseed
                    666: #   - randomorder
                    667: #
                    668: #   - encrypturl
                    669: #   - hiddenresource
                    670: #
                    671: # Parameters:
                    672: #    token - The token array from HTML::TokeParse  we mostly care about element [2]
                    673: #            which is a hash of attribute => values supplied in the tag
                    674: #            (remember this sub is only processing start tag tokens).
                    675: #    mno   - Map number.  This is used to qualify resource ids within a map
                    676: #            to make them unique course wide (a process known as uniquifaction).
                    677: #    hash  - Reference to the hash we are building.
                    678: #
                    679: sub parse_param {
                    680:     my ($token, $mno, $hash)  = @_;
                    681: 
                    682:     # Qualify the reference and name by the map number and part number.
                    683:     # if no explicit part number is supplied, 0 is the implicit part num.
                    684: 
                    685:     my $referid=$mno.'.'.$token->[2]->{'to'}; # Resource param applies to.
                    686:     my $name=$token->[2]->{'name'};	      # Name of parameter
                    687:     my $part;
                    688: 
                    689: 
                    690:     if ($name=~/^parameter_(.*)_/) { 
                    691: 	$part=$1;
                    692:     } else {
                    693: 	$part=0;
                    694:     }
                    695: 
                    696:     # Peel the parameter_ off the parameter name.
                    697: 
                    698:     $name=~s/^.*_([^_]*)$/$1/;
                    699: 
                    700:     # The value is:
                    701:     #   type.part.name.value
                    702: 
                    703:     my $newparam=
                    704: 	&escape($token->[2]->{'type'}).':'.
                    705: 	&escape($part.'.'.$name).'='.
                    706: 	&escape($token->[2]->{'value'});
                    707: 
                    708:     # The hash key is param_resourceid.
                    709:     # Multiple parameters for a single resource are & separated in the hash.
                    710: 
                    711: 
                    712:     if (defined($hash->{'param_'.$referid})) {
                    713: 	$hash->{'param_'.$referid}.='&'.$newparam;
                    714:     } else {
                    715: 	$hash->{'param_'.$referid}=''.$newparam;
                    716:     }
                    717:     #
                    718:     #  These parameters have to do with randomly selecting
                    719:     # resources, therefore a separate hash is also created to 
                    720:     # make it easy to locate them when actually computing the resource set later on
                    721:     # See the code conditionalized by ($randomize) in read_map().
                    722: 
                    723:     if ($token->[2]->{'name'}=~/^parameter_(0_)*randompick$/) { # Random selection turned on
                    724: 	$randompick{$referid}=$token->[2]->{'value'};
                    725:     }
                    726:     if ($token->[2]->{'name'}=~/^parameter_(0_)*randompickseed$/) { # Randomseed provided.
                    727: 	$randompickseed{$referid}=$token->[2]->{'value'};
                    728:     }
                    729:     if ($token->[2]->{'name'}=~/^parameter_(0_)*randomorder$/) { # Random order turned on.
                    730: 	$randomorder{$referid}=$token->[2]->{'value'};
                    731:     }
                    732: 
                    733:     # These parameters have to do with how the URLs of resources are presented to
                    734:     # course members(?).  encrypturl presents encypted url's while
                    735:     # hiddenresource hides the URL.
                    736:     #
                    737: 
                    738:     if ($token->[2]->{'name'}=~/^parameter_(0_)*encrypturl$/) {
                    739: 	if ($token->[2]->{'value'}=~/^yes$/i) {
                    740: 	    $encurl{$referid}=1;
                    741: 	}
                    742:     }
                    743:     if ($token->[2]->{'name'}=~/^parameter_(0_)*hiddenresource$/) {
                    744: 	if ($token->[2]->{'value'}=~/^yes$/i) {
                    745: 	    $hiddenurl{$referid}=1;
                    746: 	}
                    747:     }
                    748: 
                    749: }
                    750: 
                    751: 
                    752: #
                    753: #  Parses a resource tag to produce the value to push into the
                    754: #  map_ids array.
                    755: # 
                    756: #
                    757: #  Information about the actual type of resource is provided by the file extension
                    758: #  of the uri (e.g. .problem, .sequence etc. etc.).
                    759: #
                    760: #  Parameters:
                    761: #    $token   - A token from HTML::TokeParser
                    762: #               This is an array that describes the most recently parsed HTML item.
                    763: #    $lpc     - Map nesting level (?)
                    764: #    $ispage  - True if this resource is encapsulated in a .page (assembled resourcde).
                    765: #    $uri     - URI of the enclosing resource.
                    766: #    $hash    - Reference to the hash we are building.
                    767: #
                    768: # Returns:
                    769: #   Value of the id attribute of the tag.
                    770: #
                    771: # Note:
                    772: #   The token is an array that contains the following elements:
                    773: #   [0]   => 'S' indicating this is a start token
                    774: #   [1]   => 'resource'  indicating this tag is a <resource> tag.
                    775: #   [2]   => Hash of attribute =>value pairs.
                    776: #   [3]   => @(keys [2]).
                    777: #   [4]   => unused.
                    778: #
                    779: #   The attributes of the resourcde tag include:
                    780: #
                    781: #   id     - The resource id.
                    782: #   src    - The URI of the resource.
                    783: #   type   - The resource type (e.g. start and finish).
                    784: #   title  - The resource title.
                    785: #
                    786: 
                    787: sub parse_resource {
                    788:     my ($token,$lpc,$ispage,$uri, $hash) = @_;
                    789:     
                    790:     # I refuse to countenance code like this that has 
                    791:     # such a dirty side effect (and forcing this sub to be called within a loop).
                    792:     #
                    793:     #  if ($token->[2]->{'type'} eq 'zombie') { next; }
                    794:     #
                    795:     #  The original code both returns _and_ skips to the next pass of the >caller's<
                    796:     #  loop, that's just dirty.
                    797:     #
                    798: 
                    799:     # Zombie resources don't produce anything useful.
                    800: 
                    801:     if ($token->[2]->{'type'} eq 'zombie') {
                    802: 	return undef;
                    803:     }
                    804: 
                    805:     my $rid=$lpc.'.'.$token->[2]->{'id'}; # Resource id in hash is levelcounter.id-in-xml.
                    806: 
                    807:     # Save the hash element type and title:
                    808: 	    
                    809:     $hash->{'kind_'.$rid}='res';
                    810:     $hash->{'title_'.$rid}=$token->[2]->{'title'};
                    811: 
                    812:     # Get the version free URI for the resource.
                    813:     # If a 'version' attribute was supplied, and this resource's version 
                    814:     # information has not yet been stored, store it.
                    815:     #
                    816: 
                    817: 
                    818:     my $turi=&versiontrack($token->[2]->{'src'});
                    819:     if ($token->[2]->{'version'}) {
                    820: 	unless ($hash->{'version_'.$turi}) {
                    821: 
                    822: 	    #Where does the value of $1 below come from?
                    823: 	    #$1 for the regexps in versiontrack should have gone out of scope.
                    824: 	    #
                    825: 	    # I think this may be dead code since versiontrack ought to set
                    826: 	    # this hash element(?).
                    827: 	    #
                    828: 	    $hash->{'version_'.$turi}=$1;
                    829: 	}
                    830:     }
                    831:     # Pull out the title and do entity substitution on &colon
                    832:     # Q: Why no other entity substitutions?
                    833: 
                    834:     my $title=$token->[2]->{'title'};
                    835:     $title=~s/\&colon\;/\:/gs;
                    836: 
                    837: 
                    838: 
                    839:     # I think the point of all this code is to construct a final
                    840:     # URI that apache and its rewrite rules can use to
                    841:     # fetch the resource.   Thi s sonly necessary if the resource
                    842:     # is not a page.  If the resource is a page then it must be
                    843:     # assembled (at fetch time?).
                    844: 
                    845:     unless ($ispage) {
                    846: 	$turi=~/\.(\w+)$/;
                    847: 	my $embstyle=&Apache::loncommon::fileembstyle($1);
                    848: 	if ($token->[2]->{'external'} eq 'true') { # external
                    849: 	    $turi=~s/^https?\:\/\//\/adm\/wrapper\/ext\//;
                    850: 	} elsif ($turi=~/^\/*uploaded\//) { # uploaded
                    851: 	    if (($embstyle eq 'img') 
                    852: 		|| ($embstyle eq 'emb')
                    853: 		|| ($embstyle eq 'wrp')) {
                    854: 		$turi='/adm/wrapper'.$turi;
                    855: 	    } elsif ($embstyle eq 'ssi') {
                    856: 		#do nothing with these
                    857: 	    } elsif ($turi!~/\.(sequence|page)$/) {
                    858: 		$turi='/adm/coursedocs/showdoc'.$turi;
                    859: 	    }
                    860: 	} elsif ($turi=~/\S/) { # normal non-empty internal resource
                    861: 	    my $mapdir=$uri;
                    862: 	    $mapdir=~s/[^\/]+$//;
                    863: 	    $turi=&Apache::lonnet::hreflocation($mapdir,$turi);
                    864: 	    if (($embstyle eq 'img') 
                    865: 		|| ($embstyle eq 'emb')
                    866: 		|| ($embstyle eq 'wrp')) {
                    867: 		$turi='/adm/wrapper'.$turi;
                    868: 	    }
                    869: 	}
                    870:     }
                    871:     # Store reverse lookup, remove query string resource 'ids'_uri => resource id.
                    872:     # If the URI appears more than one time in the sequence, it's resourcde
                    873:     # id's are constructed as a comma spearated list.
                    874: 
                    875:     my $idsuri=$turi;
                    876:     $idsuri=~s/\?.+$//;
                    877:     if (defined($hash->{'ids_'.$idsuri})) {
                    878: 	$hash->{'ids_'.$idsuri}.=','.$rid;
                    879:     } else {
                    880: 	$hash->{'ids_'.$idsuri}=''.$rid;
                    881:     }
                    882:     
                    883: 
                    884: 
                    885:     if ($turi=~/\/(syllabus|aboutme|navmaps|smppg|bulletinboard|viewclasslist)$/) {
                    886: 	$turi.='?register=1';
                    887:     }
                    888:     
                    889: 
                    890:     # resource id lookup:  'src'_resourc-di  => URI decorated with a query
                    891:     # parameter as above if necessary due to the resource type.
                    892:     
                    893:     $hash->{'src_'.$rid}=$turi;
                    894: 
                    895:     # Mark the external-ness of the resource:
                    896:     
                    897:     if ($token->[2]->{'external'} eq 'true') {
                    898: 	$hash->{'ext_'.$rid}='true:';
                    899:     } else {
                    900: 	$hash->{'ext_'.$rid}='false:';
                    901:     }
                    902: 
                    903:     # If the resource is a start/finish resource set those
                    904:     # entries in the has so that navigation knows where everything starts.
                    905:     #   If there is a malformed sequence that has no start or no finish
                    906:     # resource, should this be detected and errors thrown?  How would such a 
                    907:     # resource come into being other than being manually constructed by a person
                    908:     # and then uploaded?  Could that happen if an author decided a sequence was almost
                    909:     # right edited it by hand and then reuploaded it to 'fix it' but accidently cut the
                    910:     #  start or finish resources?
                    911:     #
                    912:     #  All resourcess also get a type_id => (start | finish | normal)    hash entr.
                    913:     #
                    914:     if ($token->[2]->{'type'}) {
                    915: 	$hash->{'type_'.$rid}=$token->[2]->{'type'};
                    916: 	if ($token->[2]->{'type'} eq 'start') {
                    917: 	    $hash->{'map_start_'.$uri}="$rid";
                    918: 	}
                    919: 	if ($token->[2]->{'type'} eq 'finish') {
                    920: 	    $hash->{'map_finish_'.$uri}="$rid";
                    921: 	}
                    922:     }  else {
                    923: 	$hash->{'type_'.$rid}='normal';
                    924:     }
                    925: 
                    926:     # Sequences end pages are constructed entities.  They require that the 
                    927:     # map that defines _them_ be loaded as well into the hash...with this resourcde
                    928:     # as the base of the nesting.
                    929:     # Resources like that are also marked with is_map_id => 1 entries.
                    930:     #
                    931:     
                    932:     if (($turi=~/\.sequence$/) ||
                    933: 	($turi=~/\.page$/)) {
                    934: 	$hash->{'is_map_'.$rid}=1;
                    935: 	&read_map($turi,$rid, $hash);
                    936:     } 
                    937:     return $token->[2]->{'id'};
                    938: }
                    939: 
                    940: #  Links define how you are allowed to move from one resource to another.
                    941: #  They are the transition edges in the directed graph that a map is.
                    942: #  This sub takes informatino from a <link> tag and constructs the
                    943: #  navigation bits and pieces of a map.  There is no requirement that the
                    944: #  resources that are linke are already defined, however clearly the map is 
                    945: #  badly broken if they are not _eventually_ defined.
                    946: #
                    947: #  Note that links can be unconditional or conditional.
                    948: #
                    949: #  Parameters:
                    950: #     linkpc   - The link counter for this level of map nesting (this is 
                    951: #                reset to zero by read_map prior to starting to process
                    952: #                links for map).
                    953: #     lpc      - The map level ocounter (how deeply nested this map is in
                    954: #                the hierarchy of maps that are recursively read in.
                    955: #     to       - resource id (within the XML) of the target of the edge.
                    956: #     from     - resource id (within the XML) of the source of the edge.
                    957: #     condition- id of condition associated with the edge (also within the XML).
                    958: #     hash     - reference to the hash we are building.
                    959: 
                    960: #
                    961: 
                    962: sub make_link {
                    963:     my ($linkpc,$lpc,$to,$from,$condition, $hash) = @_;
                    964:     
                    965:     #  Compute fully qualified ids for the link, the 
                    966:     # and from/to by prepending lpc.
                    967:     #
                    968: 
                    969:     my $linkid=$lpc.'.'.$linkpc;
                    970:     my $goesto=$lpc.'.'.$to;
                    971:     my $comesfrom=$lpc.'.'.$from;
                    972:     my $undercond=0;
                    973: 
                    974: 
                    975:     # If there is a condition, qualify it with the level counter.
                    976: 
                    977:     if ($condition) {
                    978: 	$undercond=$lpc.'.'.$condition;
                    979:     }
                    980: 
                    981:     # Links are represnted by:
                    982:     #  goesto_.fuullyqualifedlinkid => fully qualified to
                    983:     #  comesfrom.fullyqualifiedlinkid => fully qualified from
                    984:     #  undercond_.fullyqualifiedlinkid => fully qualified condition id.
                    985: 
                    986:     $hash->{'goesto_'.$linkid}=$goesto;
                    987:     $hash->{'comesfrom_'.$linkid}=$comesfrom;
                    988:     $hash->{'undercond_'.$linkid}=$undercond;
                    989: 
                    990:     # In addition:
                    991:     #   to_.fully qualified from => comma separated list of 
                    992:     #   link ids with that from.
                    993:     # Similarly:
                    994:     #   from_.fully qualified to => comma separated list of link ids`
                    995:     #                               with that to.
                    996:     #  That allows us given a resource id to know all edges that go to it
                    997:     #  and leave from it.
                    998:     #
                    999: 
                   1000:     if (defined($hash->{'to_'.$comesfrom})) {
                   1001: 	$hash->{'to_'.$comesfrom}.=','.$linkid;
                   1002:     } else {
                   1003: 	$hash->{'to_'.$comesfrom}=''.$linkid;
                   1004:     }
                   1005:     if (defined($hash->{'from_'.$goesto})) {
                   1006: 	$hash->{'from_'.$goesto}.=','.$linkid;
                   1007:     } else {
                   1008: 	$hash->{'from_'.$goesto}=''.$linkid;
                   1009:     }
                   1010: }
                   1011: 
                   1012: # ------------------------------------------------------------------- Condition
                   1013: #
                   1014: #  Processes <condition> tags, storing sufficient information about them
                   1015: #  in the hash so that they can be evaluated and used to conditionalize
                   1016: #  what is presented to the student.
                   1017: #
                   1018: #  these can have the following attributes 
                   1019: #
                   1020: #    id    = A unique identifier of the condition within the map.
                   1021: #
                   1022: #    value = Is a perl script-let that, when evaluated in safe space
                   1023: #            determines whether or not the condition is true.
                   1024: #            Normally this takes the form of a test on an  Apache::lonnet::EXT call
                   1025: #            to find the value of variable associated with a resource in the
                   1026: #            map identified by a mapalias.
                   1027: #            Here's a fragment of XML code that illustrates this:
                   1028: #
                   1029: #           <param to="5" value="mainproblem" name="parameter_0_mapalias" type="string" />
                   1030: #           <resource src="" id="1" type="start" title="Start" />
                   1031: #           <resource src="/res/msu/albertel/b_and_c/p1.problem" id="5"  title="p1.problem" />
                   1032: #           <condition value="&EXT('user.resource.resource.0.tries','mainproblem')
                   1033: #           <2 " id="61" type="stop" />
                   1034: #           <link to="5" index="1" from="1" condition="61" />    
                   1035: #
                   1036: #           In this fragment:
                   1037: #             - The param tag establishes an alias to resource id 5 of 'mainproblem'.
                   1038: #             - The resource that is the start of the map is identified.
                   1039: #             - The resource tag identifies the resource associated with this tag
                   1040: #               and gives it the id 5.
                   1041: #             - The condition is true if the tries variable associated with mainproblem
                   1042: #               is less than 2 (that is the user has had more than 2 tries).
                   1043: #               The condition type is a stop condition which inhibits(?) the associated
                   1044: #               link if the condition  is false. 
                   1045: #             - The link to resource 5 from resource 1 is affected by this condition.    
                   1046: #            
                   1047: #    type  = Type of the condition. The type determines how the condition affects the
                   1048: #            link associated with it and is one of
                   1049: #            -  'force'
                   1050: #            -  'stop'
                   1051: #              anything else including not supplied..which treated as:
                   1052: #            - 'normal'.
                   1053: #            Presumably maps get created by the resource assembly tool and therefore
                   1054: #            illegal type values won't squirm their way into the XML.
                   1055: #   hash   - Reference to the hash we are trying to build up.
                   1056: #
                   1057: # Side effects:
                   1058: #   -  The kind_level-qualified-condition-id hash element is set to 'cond'.
                   1059: #   -  The condition text is pushed into the cond array and its element number is
                   1060: #      set in the condid_level-qualified-condition-id element of the hash.
                   1061: #   - The condition type is colon appneded to the cond array element for this condition.
                   1062: sub parse_condition {
                   1063:     my ($token, $lpc, $hash) = @_;
                   1064:     my $rid=$lpc.'.'.$token->[2]->{'id'};
                   1065:     
                   1066:     $hash->{'kind_'.$rid}='cond';
                   1067: 
                   1068:     my $condition = $token->[2]->{'value'};
                   1069:     $condition =~ s/[\n\r]+/ /gs;
                   1070:     push(@cond, $condition);
                   1071:     $hash->{'condid_'.$rid}=$#cond;
                   1072:     if ($token->[2]->{'type'}) {
                   1073: 	$cond[$#cond].=':'.$token->[2]->{'type'};
                   1074:     }  else {
                   1075: 	$cond[$#cond].=':normal';
                   1076:     }
                   1077: }
                   1078: 
                   1079: #
                   1080: #  Parse mapalias parameters.
                   1081: #  these are tags of the form:
                   1082: #  <param to="nn" 
                   1083: #         value="some-alias-for-resourceid-nn" 
                   1084: #         name="parameter_0_mapalias" 
                   1085: #         type="string" />
                   1086: #  A map alias is a textual name for a resource:
                   1087: #    - The to  attribute identifies the resource (this gets level qualified below)
                   1088: #    - The value attributes provides the alias string.
                   1089: #    - name must be of the regexp form: /^parameter_(0_)*mapalias$/
                   1090: #    - e.g. the string 'parameter_' followed by 0 or more "0_" strings
                   1091: #      terminating with the string 'mapalias'.
                   1092: #      Examples:
                   1093: #         'parameter_mapalias', 'parameter_0_mapalias', parameter_0_0_mapalias'
                   1094: #  Invalid to ids are silently ignored.
                   1095: #
                   1096: #  Parameters:
                   1097: #     token - The token array fromthe HMTML::TokeParser
                   1098: #     lpc   - The current map level counter.
                   1099: #     hash  - Reference to the hash that we are building.
                   1100: #
                   1101: sub parse_mapalias_param {
                   1102:     my ($token, $lpc, $hash) = @_;
                   1103: 
                   1104:     # Fully qualify the to value and ignore the alias if there is no
                   1105:     # corresponding resource.
                   1106: 
                   1107:     my $referid=$lpc.'.'.$token->[2]->{'to'};
                   1108:     return if (!exists($hash->{'src_'.$referid}));
                   1109: 
                   1110:     # If this is a valid mapalias parameter, 
                   1111:     # Append the target id to the count_mapalias element for that
                   1112:     # alias so that we can detect doubly defined aliases
                   1113:     # e.g.:
                   1114:     #  <param to="1" value="george" name="parameter_0_mapalias" type="string" />
                   1115:     #  <param to="2" value="george" name="parameter_0_mapalias" type="string" />
                   1116:     #
                   1117:     #  The example above is trivial but the case that's important has to do with
                   1118:     #  constructing a map that includes a nested map where the nested map may have
                   1119:     #  aliases that conflict with aliases established in the enclosing map.
                   1120:     #
                   1121:     # ...and create/update the hash mapalias entry to actually store the alias.
                   1122:     #
                   1123: 
                   1124:     if ($token->[2]->{'name'}=~/^parameter_(0_)*mapalias$/) {
                   1125: 	&count_mapalias($token->[2]->{'value'},$referid);
                   1126: 	$hash->{'mapalias_'.$token->[2]->{'value'}}=$referid;
                   1127:     }
                   1128: }
                   1129: 
                   1130: 
                   1131: #---------------------------------------------------------------------------------
                   1132: #
                   1133: #  Code to process the map file.
                   1134: 
                   1135: #  read a map file and add it to the hash.  Since a course map can contain resources
                   1136: #  that are themselves maps, read_map might be recursively called.
                   1137: #
                   1138: # Parameters:
                   1139: #   $uri         - URI of the course itself (not the map file).
                   1140: #   $parent_rid  - map number qualified id of the parent of the map being read.
                   1141: #                  For the top level course map this is 0.0.  For the first nested
                   1142: #                  map 1.n  where n is the id of the resource within the
                   1143: #                  top level map and so on.  
                   1144: #   $hash        - Reference to a hash that will become the big hash for the course
                   1145: #                  This hash is modified as per the map description.
                   1146: # Side-effects:
                   1147: #   $map_number - Will be  incremented.   This keeps track of the number of the map
                   1148: #                 we are currently working on (see parent_rid above, the number to the
                   1149: #                 left of the . in $parent_rid is the map number).
                   1150: #
                   1151: #  
                   1152: sub read_map {
                   1153:     my ($uri, $parent_rid, $hash) = @_;
                   1154: 
                   1155:     # Check for duplication: A map may only be included once.
                   1156: 
                   1157:     if($hash->{'map_pc_' . $uri}) {
1.2     ! foxr     1158: 	throw Error::Simple('Duplicate map: ', $uri);
1.1       foxr     1159:     }
                   1160:     # count the map number and save it locally so that we don't lose it
                   1161:     # when we recurse.
                   1162: 
                   1163:     $map_number++;
                   1164:     my $lmap_no = $map_number;
                   1165: 
                   1166:     # save the map_pc and map_id elements of the hash for this map:
                   1167:     #  map_pc_uri is the map number of the map with that URI.
                   1168:     #  map_id_$lmap_no is the URI for this map level.
                   1169:     #
                   1170:     $hash->{'map_pc_' . $uri}     = $lmap_no;
                   1171:     $hash->{'map_id_' . $lmap_no} = $uri;
                   1172: 
                   1173:     # Create the path up to the top of the course.
                   1174:     # this is in 'map_hierarchy_mapno'  that's a comma separated path down to us
                   1175:     # in the hierarchy:
                   1176: 
                   1177:     if ($parent_rid =~/^(\d+).\d+$/) { 
                   1178: 	my $parent_no = $1;	       # Parent's map number.
                   1179: 	if (defined($hash->{'map_hierarchy_' . $parent_no})) {
                   1180: 	    $hash->{'map_hierarchy_' . $lmap_no} =
1.2     ! foxr     1181: 		$hash->{'map_hierarchy_' . $parent_no} . ',' . $parent_no;
1.1       foxr     1182: 	} else {
                   1183: 	    # Only 1 level deep ..nothing to append to:
                   1184: 
                   1185: 	    $hash->{'map_hierarchy_' . $lmap_no} = $parent_no;
                   1186: 	}
                   1187:     }
                   1188: 
                   1189:     # figure out the name of the map file we need to read.
                   1190:     # ensure that it is a .page or a .sequence as those are the only 
                   1191:     # sorts of files that make sense for this sub 
                   1192: 
                   1193:     my $filename = &Apache::lonnet::filelocation('', &append_version($uri, $hash));
                   1194:     my $ispage = ($filename =~/\.page$/);
1.2     ! foxr     1195:     unless ($ispage || ($filename =~ /\.sequence$/)) {
1.1       foxr     1196: 	throw Error::Simple(&mt("<br />Invalid map: <tt>[_1]</tt>", $filename));
                   1197:     }
                   1198: 
                   1199:     $filename =~ /\.(\w+)$/;
                   1200: 
1.2     ! foxr     1201:     $hash->{'map_type_'.$lmap_no}=$1;
1.1       foxr     1202: 
                   1203:     # Repcopy the file and get its contents...report errors if we can't
                   1204:    
                   1205:     my $contents = &Apache::lonet::getfile($filename);
                   1206:     if($contents eq -1) {
                   1207:         throw Error::Simple(&mt('<br />Map not loaded: The file <tt>[_1]</tt> does not exist.',
                   1208: 				$filename));
                   1209:     }
                   1210:     # Now that we succesfully retrieved the file we can make our parsing passes over it:
                   1211:     # parsing is done in passes:
                   1212:     # 1. Parameters are parsed.
                   1213:     # 2. Resource, links and conditions are parsed.
                   1214:     #
                   1215:     # post processing takes care of the case where the sequence is random ordered
                   1216:     # or randomselected.
                   1217: 
                   1218:     # Parse the parameters,  This pass only cares about start tags for <param>
                   1219:     # tags.. this is because there is no body to a <param> tag.
                   1220:     #
                   1221: 
1.2     ! foxr     1222:     my $parser  = HTML::TokeParser->new(\$contents);
1.1       foxr     1223:     $parser->attr_encoded(1);	# Don't interpret entities in attributes (leave &xyz; alone).
                   1224: 
                   1225:     while (my $token = $parser->get_token()) {
                   1226: 	if (($token->[0] eq 'S') && ($token->[1] eq 'param')) { 
                   1227: 	    &parse_param($token, $map_number, $hash);
                   1228: 	}
                   1229:     }
                   1230: 
                   1231:     # ready for pass 2: Resource links and conditions.
                   1232:     # Note that if the map is random-ordered link tags are computed by randomizing
                   1233:     # resource order.  Furthermore, since conditions are set on links rather than
                   1234:     # resources, they are also not processed if random order is turned on.
                   1235:     #
                   1236: 
1.2     ! foxr     1237:     $parser = HTML::TokeParser->new(\$contents); # no way to reset the existing parser
1.1       foxr     1238:     $parser->attr_encoded(1);
                   1239: 
                   1240:     my $linkpc=0;
                   1241:     my $randomize = ($randomorder{$parent_rid} =~ /^yes$/i);
                   1242: 
                   1243:     my @map_ids;
                   1244:     while (my $token = $parser->get_token) {
                   1245: 	next if ($token->[0] ne 'S');
                   1246: 
                   1247: 	# Resource
                   1248: 
                   1249: 	if ($token->[1] eq 'resource') {
1.2     ! foxr     1250: 	    my $resource_id = &parse_resource($token,$lmap_no,$ispage,$uri, $hash);
1.1       foxr     1251: 	    if (defined $resource_id) {
                   1252: 		push(@map_ids, $resource_id); 
                   1253: 	    }
                   1254: 
                   1255:        # Link
                   1256: 
                   1257: 	} elsif ($token->[1] eq 'link' && !$randomize) {
1.2     ! foxr     1258: 	    &make_link(++$linkpc,$lmap_no,$token->[2]->{'to'},
1.1       foxr     1259: 		       $token->[2]->{'from'},
                   1260: 		       $token->[2]->{'condition'}, $hash); # note ..condition may be undefined.
                   1261: 
                   1262: 	# condition
                   1263: 
                   1264: 	} elsif ($token->[1] eq 'condition' && !$randomize) {
1.2     ! foxr     1265: 	    &parse_condition($token,$lmap_no, $hash);
1.1       foxr     1266: 	}
                   1267:     }
                   1268: 
                   1269:     #  This section handles random ordering by permuting the 
                   1270:     # IDs of the map according to the user's random seed.
                   1271:     # 
                   1272: 
                   1273:     if ($randomize) {
                   1274: 	if (!$env{'request.role.adv'}) {
                   1275: 	    my $seed;
                   1276: 
                   1277: 	    # In the advanced role, the map's random seed
                   1278: 	    # parameter is used as the basis for computing the
                   1279: 	    # seed ... if it has been specified:
                   1280: 
                   1281: 	    if (defined($randompickseed{$parent_rid})) {
                   1282: 		$seed = $randompickseed{$parent_rid};
                   1283: 	    } else {
                   1284: 
                   1285: 		# Otherwise the parent's fully encoded symb is used.
                   1286: 
                   1287: 		my ($mapid,$resid)=split(/\./,$parent_rid);
                   1288: 		my $symb=
                   1289: 		    &Apache::lonnet::encode_symb($hash->{'map_id_'.$mapid},
                   1290: 						 $resid,$hash->{'src_'.$parent_rid});
                   1291: 		
                   1292: 		$seed = $symb;
                   1293: 	    }
                   1294: 
                   1295: 
                   1296: 	    my $rndseed=&Apache::lonnet::rndseed($seed, $username, $userdomain);
                   1297: 	    &Apache::lonnet::setup_random_from_rndseed($rndseed);
                   1298: 
                   1299: 	    # Take the set of map ids we have decoded and permute them to a
                   1300: 	    # random order based on the seed set above. All of this is
                   1301: 	    # processing the randomorder parameter if it is set, not
                   1302: 	    # randompick.
                   1303: 
                   1304: 	    @map_ids=&math::Random::random_permutation(@map_ids); 
                   1305: 	}
                   1306: 
                   1307: 
                   1308: 	my $from = shift(@map_ids);
1.2     ! foxr     1309: 	my $from_rid = $lmap_no.'.'.$from;
1.1       foxr     1310: 	$hash->{'map_start_'.$uri} = $from_rid;
                   1311: 	$hash->{'type_'.$from_rid}='start';
                   1312: 
                   1313: 	# Create links to reflect the random re-ordering done above.
                   1314: 	# In the code to process the map XML, we did not process links or conditions
                   1315: 	# if randomorder was set.  This means that for an instructor to choose
                   1316: 
                   1317: 	while (my $to = shift(@map_ids)) {
1.2     ! foxr     1318: 	    &make_link(++$linkpc,$lmap_no,$to,$from);
        !          1319: 	    my $to_rid =  $lmap_no.'.'.$to;
1.1       foxr     1320: 	    $hash->{'type_'.$to_rid}='normal';
                   1321: 	    $from = $to;
                   1322: 	    $from_rid = $to_rid;
                   1323: 	}
                   1324: 
                   1325: 	$hash->{'map_finish_'.$uri}= $from_rid;
                   1326: 	$hash->{'type_'.$from_rid}='finish';
                   1327:     }
                   1328: 
                   1329:     #  The last parsing pass parses the <mapalias> tags that associate a name
                   1330:     #  with resource ids.
                   1331: 
                   1332:     $parser = HTML::TokeParser->new(\$contents);
                   1333:     $parser->attr_encoded(1);
                   1334: 
                   1335:     while (my $token = $parser->get_token) {
                   1336: 	next if ($token->[0] ne 'S');
                   1337: 	if ($token->[1] eq 'param') {
1.2     ! foxr     1338: 	    &parse_mapalias_param($token,$lmap_no, $hash);  
1.1       foxr     1339: 	} 
                   1340:     }
                   1341: 
                   1342: }
                   1343: 
                   1344: 
                   1345: #
                   1346: #  Load a map from file into a target hash.  This is done by first parsing the 
                   1347: #  map file into local hashes and then unrolling those hashes into the big hash.
                   1348: # 
                   1349: # Parameters:
                   1350: #
                   1351: #    $cnum       - number of course being read.
                   1352: #    $cdom       - Domain in which the course is evaluated.
                   1353: #    $uname      - Name of the user for whom the course is being read
                   1354: #    $udom       - Name of the domain of the user for whom the course is being read.
                   1355: #    $target_hash- Reference to the target hash into which all of this is read.
                   1356: #                  Note tht some of the hash entries we need to build require knowledge of the
                   1357: #                  course URI.. these are expected to be filled in by the caller.
                   1358: #
                   1359: # Errors are logged to lonnet and are managed via the Perl structured exception package.
                   1360: #
                   1361: #  
                   1362: sub loadmap {
                   1363:     my ($cnum, $cdom, $uname, $udom, $filepath, $target_hash) = @_;
                   1364: 
                   1365:     # Clear the auxillary hashes and the cond array.
                   1366: 
                   1367: 
                   1368:     %randompick     = ();
                   1369:     %randompickseed = ();
                   1370:     %encurl         = ();
                   1371:     %hiddenurl      = ();
1.2     ! foxr     1372:     %parmhash       = ();
1.1       foxr     1373:     @cond           = ();
1.2     ! foxr     1374:     $retfrid        = '';
1.1       foxr     1375: 
1.2     ! foxr     1376:     
1.1       foxr     1377:     # 
                   1378: 
                   1379:     $username   = $uname;
                   1380:     $userdomain = $udom;
                   1381: 
                   1382:     my $short_name = $cdom . $cnum;
                   1383: 
                   1384:     try {
                   1385: 
                   1386: 	
                   1387: 	# Get the information we need about the course.
                   1388: 	# Return without filling in anything if we can't get any info:
                   1389: 	
1.2     ! foxr     1390: 	my %cenv = &Apache::lonnet::coursedescription($short_name,
1.1       foxr     1391: 						     {'freshen_cache' => 1,
                   1392: 						      'user'          => $uname}); 
                   1393: 	unless ($cenv{'url'}) { 
                   1394: 	    &Apache::lonnet::logthis("lonmap::loadmap failed: $cnum/$cdom - did not get url");
                   1395: 	    return; 
                   1396: 	}
                   1397: 	$course_id = $cdom . '.' . $cnum; # Long course id.
                   1398: 
                   1399: 	# Load the version information into the hash
                   1400: 
                   1401: 	
                   1402: 	&process_versions(\%cenv, $target_hash);
                   1403: 	
                   1404: 	
                   1405: 	# Figure out the map filename's URI, and set up some starting points for the map.
                   1406: 	
1.2     ! foxr     1407: 	my $course_uri = $cenv{'url'};
        !          1408: 	my $map_uri    = &Apache::lonnet::clutter($course_uri);
1.1       foxr     1409: 	
                   1410: 	$target_hash->{'src_0.0'}            = &versiontrack($map_uri, $target_hash); 
                   1411: 	$target_hash->{'title_0.0'}          = &Apache::lonnet::metadata($course_uri, 'title');
1.2     ! foxr     1412: 	$target_hash->{'ids_'.$map_uri} = '0.0';
1.1       foxr     1413: 	$target_hash->{'is_map_0.0'}         = 1;
                   1414:         &read_map($course_uri, '0.0', &hash);
                   1415: 
                   1416: 	# 
                   1417: 
1.2     ! foxr     1418: 	if (defined($target_hash->{'map_start_'.$map_uri})) {
1.1       foxr     1419: 
1.2     ! foxr     1420: 	    &traceroute('0',$target_hash->{'map_start_'.$course_uri},'&', $target_hash);
        !          1421: 	    &accinit($course_uri, $short_name, $filepath, $target_hash);
        !          1422: 	    &hiddenurls($target_hash);
        !          1423: 	}
        !          1424: 	my $errors = &get_mapalias_errors($target_hash);
        !          1425: 	if ($errors ne "") {
        !          1426: 	    throw Error::Simple("Map alias errors: ", $errors);
        !          1427: 	}
        !          1428: 
        !          1429: 	# Put the versions in to src:
        !          1430: 
        !          1431: 	foreach my $key (keys(%$target_hash)) {
        !          1432: 	    if ($key =~ /^src_/) {
        !          1433: 		$target_hash->{$key} = 
        !          1434: 		    &putinversion($target_hash->{$key}, $target_hash, $short_name);
        !          1435: 	    } elsif ($key =~ /^(map_(?:start|finish|pc)_)(.*)/) {
        !          1436: 		my ($type, $url) = ($1,$2);
        !          1437: 		my $value = $target_hash->{$key};
        !          1438: 		$target_hash->{$type.&putinversion($url, $target_hash, $short_name)}=$value;
        !          1439: 	    }
1.1       foxr     1440: 	}
                   1441: 
                   1442: 	# Merge in the child hashes in case the caller wants that information as well.
                   1443: 
                   1444: 
1.2     ! foxr     1445: 	&merge_hash($target_hash, 'randompick', \%randompick);
        !          1446: 	&merge_hash($target_hash, 'randompickseed', \%randompick);
        !          1447: 	&merge_hash($target_hash, 'randomorder', \%randomorder);
        !          1448: 	&merge_hash($target_hash, 'encurl', \%encurl);
        !          1449: 	&merge_hash($target_hash, 'hiddenurl', \%hiddenurl);
        !          1450: 	&merge_hash($target_hash, 'param', \%parmhash);
        !          1451: 	&merge_conditions($target_hash);
1.1       foxr     1452:     }
                   1453:     otherwise {
                   1454: 	my $e = shift;
                   1455: 	&Apache::lonnet::logthis("lonmap::loadmap failed: " . $e->stringify());
                   1456:     }
                   1457: 
                   1458: }
                   1459: 
                   1460: 
                   1461: 1;
                   1462: 
                   1463: #
                   1464: #  Module initialization code:
                   1465: #
                   1466: 
                   1467: 1;
                   1468: __END__
                   1469: 
                   1470: =head1 NAME
                   1471: 
                   1472: Apache::lonmap - Construct a hash that represents a course (Big Hash).
                   1473: 
                   1474: =head1 SYNOPSIS
                   1475: 
                   1476: &Apache::lonmap::loadmap($filepath, \%target_hash);
                   1477: 
                   1478: =head1 INTRODUCTION
                   1479: 
                   1480: This module reads a course filename into a hash reference.  It's up to the caller
                   1481: to to things like decide the has should be tied to some external file and handle the locking
                   1482: if this file should be shared amongst several Apache children.
                   1483: 
                   1484: =head1 SUBROUTINES
                   1485: 
                   1486: =over
                   1487: 
                   1488: =item loadmap($filepath, $targethash)
                   1489: 
                   1490: 
                   1491: Reads the map file into a target hash.
                   1492: 
                   1493: =over
                   1494: 
                   1495: =item $filepath - The path to the map file to read.
                   1496: 
                   1497: =item $targethash - A reference to hash into which the course is read.
                   1498: 
                   1499: =back
                   1500: 
                   1501: =item process_versions($cenv, $hash)
                   1502: 
                   1503: Makes hash entries for each version of a course described by a course environment
                   1504: returned from Apache::lonnet::coursedescription.
                   1505: 
                   1506: =over
                   1507: 
                   1508: =item $cenv - Reference to the environment hash returned by Apache::lonnet::coursedescription
                   1509: 
                   1510: =item $hash - Hash to be filled in with 'version_xxx' entries as per the big hash.
                   1511: 
                   1512: =back
                   1513: 
                   1514: =back
                   1515:  
                   1516: 
                   1517: =cut

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