--- loncom/interface/lonnavmaps.pm 2002/02/14 22:13:36 1.26 +++ loncom/interface/lonnavmaps.pm 2002/12/12 18:24:05 1.122 @@ -1,7 +1,8 @@ + # The LearningOnline Network with CAPA # Navigate Maps Handler # -# $Id: lonnavmaps.pm,v 1.26 2002/02/14 22:13:36 harris41 Exp $ +# $Id: lonnavmaps.pm,v 1.122 2002/12/12 18:24:05 www Exp $ # # Copyright Michigan State University Board of Trustees # @@ -36,62 +37,1207 @@ # 3/1/1,6/1,17/1,29/1,30/1,2/8,9/21,9/24,9/25 Gerd Kortemeyer # YEAR=2002 # 1/1 Gerd Kortemeyer -# +# Oct-Nov Jeremy Bowers package Apache::lonnavmaps; use strict; use Apache::Constants qw(:common :http); -use Apache::lonnet(); use Apache::loncommon(); -use HTML::TokeParser; +use POSIX qw (floor strftime); + +sub handler { + my $r = shift; + real_handler($r); +} + +sub real_handler { + my $r = shift; + + &Apache::loncommon::get_unprocessed_cgi($ENV{QUERY_STRING}); + + # Handle header-only request + if ($r->header_only) { + if ($ENV{'browser.mathml'}) { + $r->content_type('text/xml'); + } else { + $r->content_type('text/html'); + } + $r->send_http_header; + return OK; + } + + # Send header, don't cache this page + if ($ENV{'browser.mathml'}) { + $r->content_type('text/xml'); + } else { + $r->content_type('text/html'); + } + &Apache::loncommon::no_cache($r); + $r->send_http_header; + + # Create the nav map + my $navmap = Apache::lonnavmaps::navmap->new( + $ENV{"request.course.fn"}.".db", + $ENV{"request.course.fn"}."_parms.db", 1, 1); + + + if (!defined($navmap)) { + my $requrl = $r->uri; + $ENV{'user.error.msg'} = "$requrl:bre:0:0:Course not initialized"; + return HTTP_NOT_ACCEPTABLE; + } + + $r->print("\n"); + $r->print("Navigate Course Contents"); + + # Header + $r->print(&Apache::loncommon::bodytag('Navigate Course Contents','', + '')); + $r->print(''); + + $r->print(''); + my $date=localtime; + $r->print(''); + + # Print discussions and feedback header + if ($navmap->{LAST_CHECK}) { + $r->print(''); + } else { + $r->print(''); + } + $r->print('
Key:    '. + ' New discussion since '. + strftime("%A, %b %e at %I:%M %P", localtime($navmap->{LAST_CHECK})). + '  '. + ' New message (click to open)

'. + '

  '. + ' Discussions'. + '   New message (click to open)'. + '
'); + + my $condition = 0; + if ($ENV{'form.condition'}) { + $condition = 1; + } + + # Determine where the "here" marker is and where the screen jumps to. + my $SYMB = 1; my $URL = 2; my $NOTHING = 3; # symbolic constants + my $hereType; # the type of marker, $SYMB, $URL, or $NOTHING + my $here; # the actual URL or SYMB for the here marker + my $jumpType; # The type of the thing we have a jump for, $SYMB or $URL + my $jump; # the SYMB/URL of the resource we need to jump to + + if ( $ENV{'form.alreadyHere'} ) { # we came from a user's manipulation of the nav page + # If this is a click on a folder or something, we want to preserve the "here" + # from the querystring, and get the new "jump" marker + $hereType = $ENV{'form.hereType'}; + $here = $ENV{'form.here'}; + $jumpType = $ENV{'form.jumpType'} || $NOTHING; + $jump = $ENV{'form.jump'}; + } else { # the user is visiting the nav map from the remote + # We're coming from the remote. We have either a url, a symb, or nothing, + # and we need to figure out what. + # Preference: Symb + + if ($ENV{'form.symb'}) { + $hereType = $jumpType = $SYMB; + $here = $jump = $ENV{'form.symb'}; + } elsif ($ENV{'form.postdata'}) { + # couldn't find a symb, is there a URL? + my $currenturl = $ENV{'form.postdata'}; + $currenturl=~s/^http\:\/\///; + $currenturl=~s/^[^\/]+//; + + $hereType = $jumpType = $URL; + $here = $jump = $currenturl; + } else { + # Nothing + $hereType = $jumpType = $NOTHING; + } + } + + + # alreadyHere allows us to only open the maps necessary to view + # the current location once, while at the same time remembering + # the current location. Without that check, the user would never + # be able to close those maps; the user would close it, and the + # currenturl scan would re-open it. + my $queryAdd = "&alreadyHere=1"; + + if ($condition) { + $r->print("Close All Folders"); + } else { + $r->print("Open All Folders"); + } + + $r->print('
 '); + $r->rflush(); + + # Now that we've displayed some stuff to the user, init the navmap + $navmap->init(); + + # Check that it's defined + if (!($navmap->courseMapDefined())) { + $r->print('Coursemap undefined.' . + ''); + return OK; + } + + # Grab a resource object so we have access to the constants; this + # is technically not proper, but should be harmless + my $res = $navmap->firstResource(); + + # These are some data tables, which make it easy to change some of + # of the specific visualization parameters if desired. + + # Defines a status->color mapping, null string means don't color + my %colormap = + ( $res->NETWORK_FAILURE => '', + $res->CORRECT => '', + $res->EXCUSED => '#3333FF', + $res->PAST_DUE_ANSWER_LATER => '', + $res->PAST_DUE_NO_ANSWER => '', + $res->ANSWER_OPEN => '#006600', + $res->OPEN_LATER => '', + $res->TRIES_LEFT => '', + $res->INCORRECT => '', + $res->OPEN => '', + $res->NOTHING_SET => '' ); + # And a special case in the nav map; what to do when the assignment + # is not yet done and due in less then 24 hours + my $hurryUpColor = "#FF0000"; + + # Keep these mappings in sync with lonquickgrades, which uses the colors + # instead of the icons. + my %statusIconMap = + ( $res->NETWORK_FAILURE => '', + $res->NOTHING_SET => '', + $res->CORRECT => 'navmap.correct.gif', + $res->EXCUSED => 'navmap.correct.gif', + $res->PAST_DUE_NO_ANSWER => 'navmap.wrong.gif', + $res->PAST_DUE_ANSWER_LATER => 'navmap.wrong.gif', + $res->ANSWER_OPEN => 'navmap.wrong.gif', + $res->OPEN_LATER => '', + $res->TRIES_LEFT => 'navmap.open.gif', + $res->INCORRECT => 'navmap.wrong.gif', + $res->OPEN => 'navmap.open.gif', + $res->ATTEMPTED => 'navmap.open.gif' ); + + my %iconAltTags = + ( 'navmap.correct.gif' => 'Correct', + 'navmap.wrong.gif' => 'Incorrect', + 'navmap.open.gif' => 'Open' ); + + my %condenseStatuses = + ( $res->NETWORK_FAILURE => 1, + $res->NOTHING_SET => 1, + $res->CORRECT => 1 ); + + my %filterHash; + # Figure out what we're not displaying + foreach (split(/\,/, $ENV{"form.filter"})) { + if ($_) { + $filterHash{$_} = "1"; + } + } + + # Is this a new-style course? If so, we want to suppress showing the top-level + # maps in their own folders, in favor of "inlining" them. + my $topResource = $navmap->getById("0.0"); + + # Begin the HTML table + # four cols: resource + indent, chat+feedback, icon, text string + $r->print('' ."\n"); + + # This needs to be updated to use symbs from the remote, + # instead of uris. The changes to this and the main rendering + # loop should be obvious. + # Here's a simple example of the iterator. + # Preprocess the map: Look for current URL, force inlined maps to display + + my $mapIterator = $navmap->getIterator(undef, undef, undef, 1); + my $found = 0; + my $depth = 1; + my $currentJumpIndex = 0; # keeps track of when the current resource is found, + # so we can back up a few and put the anchor above the + # current resource + my $currentJumpDelta = 2; # change this to change how many resources are displayed + # before the current resource when using #current + $mapIterator->next(); # discard the first BEGIN_MAP + my $curRes = $mapIterator->next(); + my $counter = 0; + my $foundJump = ($jumpType == $NOTHING); # look for jump point if we have one + my $looped = 0; + + # We only need to do this if we need to open the maps to show the + # current position. This will change the counter so we can't count + # for the jump marker with this loop. + while ($depth > 0 && !$ENV{'form.alreadyHere'}) { + if ($curRes == $mapIterator->BEGIN_MAP()) { $depth++; } + if ($curRes == $mapIterator->END_MAP()) { $depth--; } + + if (ref($curRes) && !$ENV{'form.alreadyHere'} && + ($hereType == $SYMB && $curRes->symb() eq $here) || + (ref($curRes) && $hereType == $URL && $curRes->src() eq $here)) { + my $mapStack = $mapIterator->getStack(); + + # Ensure the parent maps are open + for my $map (@{$mapStack}) { + if ($condition) { + undef $filterHash{$map->map_pc()}; + } else { + $filterHash{$map->map_pc()} = 1; + } + } + $ENV{'form.alreadyHere'} = 1; + } + $looped = 1; + + $curRes = $mapIterator->next(); + } + + $mapIterator = $navmap->getIterator(undef, undef, \%filterHash, 0); + $depth = 1; + $mapIterator->next(); + $curRes = $mapIterator->next(); + + while ($depth > 0 && !$foundJump) { + if ($curRes == $mapIterator->BEGIN_MAP()) { $depth++; } + if ($curRes == $mapIterator->END_MAP()) { $depth--; } + if (ref($curRes)) { $counter++; } + + if (ref($curRes) && + (($jumpType == $SYMB && $curRes->symb() eq $jump) || + ($jumpType == $URL && $curRes->src() eq $jump))) { + # If this is the correct resource, be sure to + # show it by making sure the containing maps + # are open. + + # This is why we have to use the main iterator instead of the + # potentially faster DFS: The count has to be the same, so + # the order has to be the same, which DFS won't give us. + $currentJumpIndex = $counter; + $foundJump = 1; + } + + $curRes = $mapIterator->next(); + } + + undef $res; # so we don't accidentally use it later + my $indentLevel = 0; + my $indentString = "\"\""; + + my $isNewBranch = 0; + my $now = time(); + my $in24Hours = $now + 24 * 60 * 60; + my $displayedHereMarker = 0; + my $displayedJumpMarker = 0; + + # We know the first thing is a BEGIN_MAP (see "$self->{STARTED}" + # code in iterator->next), so ignore the first one + $mapIterator = $navmap->getIterator(undef, undef, \%filterHash, + $condition); + $mapIterator->next(); + $curRes = $mapIterator->next(); + $depth = 1; + + my @backgroundColors = ("#FFFFFF", "#F6F6F6"); + my $rowNum = 0; + + $counter = 0; + + while ($depth > 0) { + if ($curRes == $mapIterator->BEGIN_MAP() || + $curRes == $mapIterator->BEGIN_BRANCH()) { + $indentLevel++; + } + if ($curRes == $mapIterator->END_MAP() || + $curRes == $mapIterator->END_BRANCH()) { + $indentLevel--; + } + if ($curRes == $mapIterator->BEGIN_BRANCH()) { + $isNewBranch = 1; + } + if ($curRes == $mapIterator->BEGIN_MAP()) { $depth++; } + if ($curRes == $mapIterator->END_MAP()) { $depth--; } + + if (ref($curRes)) { $counter++; } + + # Is this resource being ignored because it is in a random-out + # map and it was not selected? + if (ref($curRes) && !advancedUser() && $curRes->randomout()) { + $curRes = $mapIterator->next(); + next; # if yes, then just ignore this resource + } + + if (ref($curRes)) { + + my $deltalevel = $isNewBranch? 1 : 0; # reserves space for branch icon + + if ($indentLevel - $deltalevel < 0) { + # If this would be at a negative depth (top-level maps in + # new-style courses, we want to suppress their title display) + # then ignore it. + $curRes = $mapIterator->next(); + next; + } + + # Step one: Decide which parts to show + my @parts = @{$curRes->parts()}; + my $multipart = scalar(@parts) > 1; + my $condensed = 0; + + if ($curRes->is_problem()) { + + # Is it multipart? + if ($multipart) { + # If it's multipart, see if part 0 is "open" + # if it is, display all parts, if it isn't, + # just display first + if (!$curRes->opendate("0")) { + # no parts are open, display as one part + @parts = ("0"); + $condensed = 1; + } else { + # Otherwise, only display part 0 if we want to + # attach feedback or email information to it + if ($curRes->hasDiscussion() || $curRes->getFeedback()) { + shift @parts; + } else { + # Now, we decide whether to condense the + # parts due to similarity + my $status = $curRes->status($parts[1]); + my $due = $curRes->duedate($parts[1]); + my $open = $curRes->opendate($parts[1]); + my $statusAllSame = 1; + my $dueAllSame = 1; + my $openAllSame = 1; + for (my $i = 2; $i < scalar(@parts); $i++) { + if ($curRes->status($parts[$i]) != $status){ + $statusAllSame = 0; + } + if ($curRes->duedate($parts[$i]) != $due ) { + $dueAllSame = 0; + } + if ($curRes->opendate($parts[$i]) != $open) { + $openAllSame = 0; + } + } + + # $allSame is true if all the statuses were + # the same. Now, if they are all the same and + # match one of the statuses to condense, or they + # are all open with the same due date, or they are + # all OPEN_LATER with the same open date, display the + # status of the first non-zero part (to get the 'correct' + # status right, since 0 is never 'correct' or 'open'). + if (($statusAllSame && defined($condenseStatuses{$status})) || + ($dueAllSame && $status == $curRes->OPEN && $statusAllSame)|| + ($openAllSame && $status == $curRes->OPEN_LATER && $statusAllSame) ){ + @parts = ($parts[1]); + $condensed = 1; + } + } + } + } + + } else { + $parts[0] = "0"; # this is to get past foreach loop below + # you can consider a non-problem resource as a resource + # with only one part without loss, and it simplifies the looping + } + + # Is it a multipart problem with a single part, now in + # @parts with "0" filtered out? If so, 'forget' it's a multi-part + # problem and treat it like a single-part problem. + if ( scalar(@parts) == 1 ) { + $multipart = 0; + } + + # Display one part, in event of network error. + # If this is a single part, we can at least show the correct + # status, but if it's multipart, we're lost, since we can't + # retreive the metadata to count the parts + if ($curRes->{RESOURCE_ERROR}) { + @parts = ("0"); + } + + # Step Two: Print the actual data. + + # For each part we intend to display... + foreach my $part (@parts) { + + my $nonLinkedText = ""; # unlinked stuff after title + + my $stack = $mapIterator->getStack(); + my $src = getLinkForResource($stack); + + # Pass the correct symb on the querystring, so the + # remote will figure out where we are if we click a link + my $srcHasQuestion = $src =~ /\?/; + my $link = $src. + ($srcHasQuestion?'&':'?') . + 'symb='.&Apache::lonnet::escape($curRes->symb()). + '"'; + + my $title = $curRes->compTitle(); + if ($src=~/^\/uploaded\//) { + $nonLinkedText=$title; + $title=''; + } + my $partLabel = ""; + my $newBranchText = ""; + + # If this is a new branch, label it so + if ($isNewBranch) { + $newBranchText = ""; + $isNewBranch = 0; + } + + # links to open and close the folders + my $linkopen = ""; + my $linkclose = ""; + + my $icon = "\"\""; + if ($curRes->is_problem()) { + if ($part eq "0" || $condensed) { + $icon = ''; + } else { + $icon = $indentString; + } + } + + # Display the correct icon, link to open or shut map + if ($curRes->is_map()) { + my $mapId = $curRes->map_pc(); + my $nowOpen = (!defined($filterHash{$mapId})); + if ($condition) {$nowOpen = !$nowOpen;} + $icon = $nowOpen ? + "navmap.folder.closed.gif" : "navmap.folder.open.gif"; + $icon = "\"\""; + $linkopen = ""; + $linkclose = ""; + + } + + my $colorizer = ""; + my $color; + if ($curRes->is_problem()) { + $color = $colormap{$curRes->status}; + + if (dueInLessThen24Hours($curRes, $part) || + lastTry($curRes, $part)) { + $color = $hurryUpColor; + } + + if ($color ne "") { + $colorizer = "bgcolor=\"$color\""; + } + } + + if ($curRes->randomout()) { + $nonLinkedText .= ' (hidden) '; + } + + $rowNum++; + my $backgroundColor = $backgroundColors[$rowNum % scalar(@backgroundColors)]; + + # FIRST COL: The resource indentation, branch icon, name, and anchor + $r->print(" \n"); + + # SECOND COL: Is there text, feedback, errors?? + my $discussionHTML = ""; my $feedbackHTML = ""; + + if ($curRes->hasDiscussion()) { + $discussionHTML = $linkopen . + '' . + $linkclose; + } + + if ($curRes->getFeedback()) { + my $feedback = $curRes->getFeedback(); + foreach (split(/\,/, $feedback)) { + if ($_) { + $feedbackHTML .= ' ' + . ''; + } + } + } + + $r->print(""); + + # Is this the first displayed part of a multi-part problem + # that has not been condensed, so we should suppress these two + # columns so we don't display useless status info about part + # "0"? + my $firstDisplayed = !$condensed && $multipart && $part eq "0"; + + # THIRD COL: Problem status icon + if ($curRes->is_problem() && + !$firstDisplayed) { + my $icon = $statusIconMap{$curRes->status($part)}; + my $alt = $iconAltTags{$icon}; + if ($icon) { + $r->print("\n"); + } else { + $r->print("\n"); + } + } else { # not problem, no icon + $r->print("\n"); + } + + # FOURTH COL: Text description + $r->print("\n"); + + if (!($counter % 20)) { $r->rflush(); } + if ($counter == 2) { $r->rflush(); } + } + } + $curRes = $mapIterator->next(); + } + + $r->print("
\n"); + + # Print the anchor if necessary + if ($counter == $currentJumpIndex - $currentJumpDelta ) { + $r->print(''); + $displayedJumpMarker = 1; + } + + # print indentation + for (my $i = 0; $i < $indentLevel - $deltalevel; $i++) { + $r->print($indentString); + } + + $r->print(" ${newBranchText}${linkopen}$icon${linkclose}\n"); + + my $curMarkerBegin = ""; + my $curMarkerEnd = ""; + + # Is this the current resource? + if (!$displayedHereMarker && + (($hereType == $SYMB && $curRes->symb eq $here) || + ($hereType == $URL && $curRes->src eq $here))) { + $curMarkerBegin = '> '; + $curMarkerEnd = ' <'; + $displayedHereMarker = 1; + } + + if ($curRes->is_problem() && $part ne "0" && !$condensed) { + $partLabel = " (Part $part)"; + $title = ""; + } + if ($multipart && $condensed) { + $nonLinkedText .= ' (' . $curRes->countParts() . ' parts)'; + } + + $r->print(" $curMarkerBegin$title$partLabel $curMarkerEnd $nonLinkedText"); + + #if ($curRes->{RESOURCE_ERROR}) { + # $r->print(&Apache::loncommon::help_open_topic ("Navmap_Host_Down", + # 'Host down')); + # } + + $r->print("$discussionHTML$feedbackHTML $linkopen\"$alt\"$linkclose  \n"); + + if ($curRes->kind() eq "res" && + $curRes->is_problem() && + !$firstDisplayed) { + $r->print ("") if ($color); + $r->print (getDescription($curRes, $part)); + $r->print ("") if ($color); + } + if ($curRes->is_map() && advancedUser() && $curRes->randompick()) { + $r->print('(randomly select ' . $curRes->randompick() .')'); + } + + $r->print(" 
"); + + # Print out the part that jumps to #curloc if it exists + if ($displayedJumpMarker) { + $r->print(''); + } + + $r->print(""); + + $navmap->untieHashes(); + + return OK; +} + +# Convenience functions: Returns a string that adds or subtracts +# the second argument from the first hash, appropriate for the +# query string that determines which folders to recurse on +sub addToFilter { + my $hashIn = shift; + my $addition = shift; + my %hash = %$hashIn; + $hash{$addition} = 1; + + return join (",", keys(%hash)); +} + +sub removeFromFilter { + my $hashIn = shift; + my $subtraction = shift; + my %hash = %$hashIn; + + delete $hash{$subtraction}; + return join(",", keys(%hash)); +} + +# Convenience function: Given a stack returned from getStack on the iterator, +# return the correct src() value. +# Later, this should add an anchor when we start putting anchors in pages. +sub getLinkForResource { + my $stack = shift; + my $res; + + # Check to see if there are any pages in the stack + foreach $res (@$stack) { + if (defined($res) && $res->is_page()) { + return $res->src(); + } + } + + # Failing that, return the src of the last resource that is defined + # (when we first recurse on a map, it puts an undefined resource + # on the bottom because $self->{HERE} isn't defined yet, and we + # want the src for the map anyhow) + foreach (@$stack) { + if (defined($_)) { $res = $_; } + } + + return $res->src(); +} + +# Convenience function: This seperates the logic of how to create +# the problem text strings ("Due: DATE", "Open: DATE", "Not yet assigned", +# etc.) into a seperate function. It takes a resource object as the +# first parameter, and the part number of the resource as the second. +# It's basically a big switch statement on the status of the resource. + +sub getDescription { + my $res = shift; + my $part = shift; + my $status = $res->status($part); + + if ($status == $res->NETWORK_FAILURE) { return ""; } + if ($status == $res->NOTHING_SET) { + return "Not currently assigned."; + } + if ($status == $res->OPEN_LATER) { + return "Open " . timeToHumanString($res->opendate($part)); + } + if ($status == $res->OPEN) { + if ($res->duedate($part)) { + return "Due " . timeToHumanString($res->duedate($part)); + } else { + return "Open, no due date"; + } + } + if ($status == $res->PAST_DUE_ANSWER_LATER) { + return "Answer open " . timeToHumanString($res->answerdate($part)); + } + if ($status == $res->PAST_DUE_NO_ANSWER) { + return "Was due " . timeToHumanString($res->duedate($part)); + } + if ($status == $res->ANSWER_OPEN) { + return "Answer available"; + } + if ($status == $res->EXCUSED) { + return "Excused by instructor"; + } + if ($status == $res->ATTEMPTED) { + return "Not yet graded."; + } + if ($status == $res->TRIES_LEFT) { + my $tries = $res->tries($part); + my $maxtries = $res->maxtries($part); + my $triesString = ""; + if ($tries && $maxtries) { + $triesString = "($tries of $maxtries tries used)"; + if ($maxtries > 1 && $maxtries - $tries == 1) { + $triesString = "$triesString"; + } + } + if ($res->duedate()) { + return "Due " . timeToHumanString($res->duedate($part)) . + " $triesString"; + } else { + return "No due date $triesString"; + } + } +} + +# Convenience function, so others can use it: Is the problem due in less then +# 24 hours, and still can be done? + +sub dueInLessThen24Hours { + my $res = shift; + my $part = shift; + my $status = $res->status($part); + + return ($status == $res->OPEN() || $status == $res->ATTEMPTED() || + $status == $res->TRIES_LEFT()) && + $res->duedate() && $res->duedate() < time()+(24*60*60) && + $res->duedate() > time(); +} + +# Convenience function, so others can use it: Is there only one try remaining for the +# part, with more then one try to begin with, not due yet and still can be done? +sub lastTry { + my $res = shift; + my $part = shift; + + my $tries = $res->tries($part); + my $maxtries = $res->maxtries($part); + return $tries && $maxtries && $maxtries > 1 && + $maxtries - $tries == 1 && $res->duedate() && + $res->duedate() > time(); +} + +# This puts a human-readable name on the ENV variable. +sub advancedUser { + return $ENV{'user.adv'}; +} + + +# timeToHumanString takes a time number and converts it to a +# human-readable representation, meant to be used in the following +# manner: +# print "Due $timestring" +# print "Open $timestring" +# print "Answer available $timestring" +# Very, very, very, VERY English-only... goodness help a localizer on +# this func... +sub timeToHumanString { + my ($time) = @_; + # zero, '0' and blank are bad times + if (!$time) { + return 'never'; + } + + my $now = time(); + + my @time = localtime($time); + my @now = localtime($now); + + # Positive = future + my $delta = $time - $now; + + my $minute = 60; + my $hour = 60 * $minute; + my $day = 24 * $hour; + my $week = 7 * $day; + my $inPast = 0; + + # Logic in comments: + # Is it now? (extremely unlikely) + if ( $delta == 0 ) { + return "this instant"; + } + + if ($delta < 0) { + $inPast = 1; + $delta = -$delta; + } + + if ( $delta > 0 ) { + + my $tense = $inPast ? " ago" : ""; + my $prefix = $inPast ? "" : "in "; + + # Less then a minute + if ( $delta < $minute ) { + if ($delta == 1) { return "${prefix}1 second$tense"; } + return "$prefix$delta seconds$tense"; + } + + # Less then an hour + if ( $delta < $hour ) { + # If so, use minutes + my $minutes = floor($delta / 60); + if ($minutes == 1) { return "${prefix}1 minute$tense"; } + return "$prefix$minutes minutes$tense"; + } + + # Is it less then 24 hours away? If so, + # display hours + minutes + if ( $delta < $hour * 24) { + my $hours = floor($delta / $hour); + my $minutes = floor(($delta % $hour) / $minute); + my $hourString = "$hours hours"; + my $minuteString = ", $minutes minutes"; + if ($hours == 1) { + $hourString = "1 hour"; + } + if ($minutes == 1) { + $minuteString = ", 1 minute"; + } + if ($minutes == 0) { + $minuteString = ""; + } + return "$prefix$hourString$minuteString$tense"; + } + + # Less then 5 days away, display day of the week and + # HH:MM + if ( $delta < $day * 5 ) { + my $timeStr = strftime("%A, %b %e at %I:%M %P", localtime($time)); + $timeStr =~ s/12:00 am/midnight/; + $timeStr =~ s/12:00 pm/noon/; + return ($inPast ? "last " : "next ") . + $timeStr; + } + + # Is it this year? + if ( $time[5] == $now[5]) { + # Return on Month Day, HH:MM meridian + my $timeStr = strftime("on %A, %b %e at %I:%M %P", localtime($time)); + $timeStr =~ s/12:00 am/midnight/; + $timeStr =~ s/12:00 pm/noon/; + return $timeStr; + } + + # Not this year, so show the year + my $timeStr = strftime("on %A, %b %e %G at %I:%M %P", localtime($time)); + $timeStr =~ s/12:00 am/midnight/; + $timeStr =~ s/12:00 pm/noon/; + return $timeStr; + } +} + +1; + +package Apache::lonnavmaps::navmap; + +=pod + +lonnavmaps provides functions and objects for dealing with the compiled course hashes generated when a user enters the course, and also provides the Apache handler for the "Navigation Map" button. + +=head1 navmap object: Encapsulating the compiled nav map + +navmap is an object that encapsulates a compiled course map and provides a reasonable interface to it. + +Most notably it provides a way to navigate the map sensibly and a flexible iterator that makes it easy to write various renderers based on nav maps. + +You must obtain resource objects through the navmap object. + +=head2 Methods + +=over 4 + +=item * B(navHashFile, parmHashFile, genCourseAndUserOptions, genMailDiscussStatus): Binds a new navmap object to the compiled nav map hash and parm hash given as filenames. genCourseAndUserOptions is a flag saying whether the course options and user options hash should be generated. This is for when you are using the parameters of the resources that require them; see documentation in resource object documentation. genMailDiscussStatus causes the nav map to retreive information about the email and discussion status of resources. Returns the navmap object if this is successful, or B if not. You must check for undef; errors will occur when you try to use the other methods otherwise. + +=item * B(first, finish, filter, condition): See iterator documentation below. + +=cut + +use strict; use GDBM_File; -# -------------------------------------------------------------- Module Globals -my %hash; -my @rows; +sub new { + # magic invocation to create a class instance + my $proto = shift; + my $class = ref($proto) || $proto; + my $self = {}; + + $self->{NAV_HASH_FILE} = shift; + $self->{PARM_HASH_FILE} = shift; + $self->{GENERATE_COURSE_USER_OPT} = shift; + $self->{GENERATE_EMAIL_DISCUSS_STATUS} = shift; + + # Resource cache stores navmap resources as we reference them. We generate + # them on-demand so we don't pay for creating resources unless we use them. + $self->{RESOURCE_CACHE} = {}; + + # Network failure flag, if we accessed the course or user opt and + # failed + $self->{NETWORK_FAILURE} = 0; + + # tie the nav hash + my %navmaphash; + if (!(tie(%navmaphash, 'GDBM_File', $self->{NAV_HASH_FILE}, + &GDBM_READER(), 0640))) { + return undef; + } + + my %parmhash; + if (!(tie(%parmhash, 'GDBM_File', $self->{PARM_HASH_FILE}, + &GDBM_READER(), 0640))) + { + untie $self->{PARM_HASH}; + return undef; + } -# -# These cache hashes need to be independent of user, resource and course -# (user and course can/should be in the keys) -# + # Now copy the hashes for speed (?) + my %realnav; my %realparm; + foreach (%navmaphash) { $realnav{$_} = $navmaphash{$_}; } + foreach (%parmhash) { $realparm{$_} = $navmaphash{$_}; } + $self->{NAV_HASH} = \%realnav; + $self->{PARM_HASH} = \%realparm; + + bless($self); + $self->untieHashes(); + + return $self; +} -my %courserdatas; -my %userrdatas; +sub init { + my $self = shift; -# -# These global hashes are dependent on user, course and resource, -# and need to be initialized every time when a sheet is calculated -# -my %courseopt; -my %useropt; -my %parmhash; + # If the course opt hash and the user opt hash should be generated, + # generate them + if ($self->{GENERATE_COURSE_USER_OPT}) { + my $uname=$ENV{'user.name'}; + my $udom=$ENV{'user.domain'}; + my $uhome=$ENV{'user.home'}; + my $cid=$ENV{'request.course.id'}; + my $chome=$ENV{'course.'.$cid.'.home'}; + my ($cdom,$cnum)=split(/\_/,$cid); + + my $userprefix=$uname.'_'.$udom.'_'; + + my %courserdatas; my %useropt; my %courseopt; my %userrdatas; + unless ($uhome eq 'no_host') { +# ------------------------------------------------- Get coursedata (if present) + unless ((time-$courserdatas{$cid.'.last_cache'})<240) { + my $reply=&Apache::lonnet::reply('dump:'.$cdom.':'.$cnum. + ':resourcedata',$chome); + if ($reply!~/^error\:/) { + $courserdatas{$cid}=$reply; + $courserdatas{$cid.'.last_cache'}=time; + } + # check to see if network failed + elsif ( $reply=~/no.such.host/i || $reply=~/con.*lost/i ) + { + $self->{NETWORK_FAILURE} = 1; + } + } + foreach (split(/\&/,$courserdatas{$cid})) { + my ($name,$value)=split(/\=/,$_); + $courseopt{$userprefix.&Apache::lonnet::unescape($name)}= + &Apache::lonnet::unescape($value); + } +# --------------------------------------------------- Get userdata (if present) + unless ((time-$userrdatas{$uname.'___'.$udom.'.last_cache'})<240) { + my $reply=&Apache::lonnet::reply('dump:'.$udom.':'.$uname.':resourcedata',$uhome); + if ($reply!~/^error\:/) { + $userrdatas{$uname.'___'.$udom}=$reply; + $userrdatas{$uname.'___'.$udom.'.last_cache'}=time; + } + # check to see if network failed + elsif ( $reply=~/no.such.host/i || $reply=~/con.*lost/i ) + { + $self->{NETWORK_FAILURE} = 1; + } + } + foreach (split(/\&/,$userrdatas{$uname.'___'.$udom})) { + my ($name,$value)=split(/\=/,$_); + $useropt{$userprefix.&Apache::lonnet::unescape($name)}= + &Apache::lonnet::unescape($value); + } + $self->{COURSE_OPT} = \%courseopt; + $self->{USER_OPT} = \%useropt; + } + } + + if ($self->{GENERATE_EMAIL_DISCUSS_STATUS}) { + my $cid=$ENV{'request.course.id'}; + my ($cdom,$cnum)=split(/\_/,$cid); + + my %emailstatus = &Apache::lonnet::dump('email_status'); + my $logoutTime = $emailstatus{'logout'}; + my $courseLeaveTime = $emailstatus{'logout_'.$ENV{'request.course.id'}}; + $self->{LAST_CHECK} = ($courseLeaveTime > $logoutTime ? + $courseLeaveTime : $logoutTime); + my %discussiontime = &Apache::lonnet::dump('discussiontimes', + $cdom, $cnum); + my %feedback=(); + my %error=(); + my $keys = &Apache::lonnet::reply('keys:'. + $ENV{'user.domain'}.':'. + $ENV{'user.name'}.':nohist_email', + $ENV{'user.home'}); + + foreach my $msgid (split(/\&/, $keys)) { + $msgid=&Apache::lonnet::unescape($msgid); + my $plain=&Apache::lonnet::unescape(&Apache::lonnet::unescape($msgid)); + if ($plain=~/(Error|Feedback) \[([^\]]+)\]/) { + my ($what,$url)=($1,$2); + my %status= + &Apache::lonnet::get('email_status',[$msgid]); + if ($status{$msgid}=~/^error\:/) { + $status{$msgid}=''; + } + + if (($status{$msgid} eq 'new') || + (!$status{$msgid})) { + if ($what eq 'Error') { + $error{$url}.=','.$msgid; + } else { + $feedback{$url}.=','.$msgid; + } + } + } + } + + $self->{FEEDBACK} = \%feedback; + $self->{ERROR_MSG} = \%error; # what is this? JB + $self->{DISCUSSION_TIME} = \%discussiontime; + $self->{EMAIL_STATUS} = \%emailstatus; + + } + + $self->{PARM_CACHE} = {}; +} + +# Internal function: Takes a key to look up in the nav hash and implements internal +# memory caching of that key. +sub navhash { + my $self = shift; my $key = shift; + return $self->{NAV_HASH}->{$key}; +} + +# Checks to see if coursemap is defined, matching test in old lonnavmaps +sub courseMapDefined { + my $self = shift; + my $uri = &Apache::lonnet::clutter($ENV{'request.course.uri'}); + + my $firstres = $self->navhash("map_start_$uri"); + my $lastres = $self->navhash("map_finish_$uri"); + return $firstres && $lastres; +} + +sub getIterator { + my $self = shift; + my $iterator = Apache::lonnavmaps::iterator->new($self, shift, shift, + shift, undef, shift); + return $iterator; +} + +# unties the hash when done +sub untieHashes { + my $self = shift; + untie %{$self->{NAV_HASH}} if ($self->{HASH_TIED}); + untie %{$self->{PARM_HASH}} if ($self->{HASH_TIED}); + $self->{HASH_TIED} = 0; +} + +# when the object is destroyed, be sure to untie all the hashes we tied. +sub DESTROY { + my $self = shift; + $self->untieHashes(); +} + +# Private function: Does the given resource (as a symb string) have +# current discussion? Returns 0 if chat/mail data not extracted. +sub hasDiscussion { + my $self = shift; + my $symb = shift; + if (!defined($self->{DISCUSSION_TIME})) { return 0; } + + return $self->{DISCUSSION_TIME}->{$symb} > + $self->{LAST_CHECK}; +} + +# Private function: Does the given resource (as a symb string) have +# current feedback? Returns the string in the feedback hash, which +# will be false if it does not exist. +sub getFeedback { + my $self = shift; + my $symb = shift; + + if (!defined($self->{FEEDBACK})) { return ""; } + + return $self->{FEEDBACK}->{$symb}; +} -# ------------------------------------------------------------------ Euclid gcd +=pod -sub euclid { - my ($e,$f)=@_; - my $a; my $b; my $r; - if ($e>$f) { $b=$e; $r=$f; } else { $r=$e; $b=$f; } - while ($r!=0) { - $a=$b; $b=$r; - $r=$a%$b; +=item * B(id): Based on the ID of the resource (1.1, 3.2, etc.), get a resource object for that resource. This method, or other methods that use it (as in the resource object) is the only proper way to obtain a resource object. + +=cut + +# The strategy here is to cache the resource objects, and only construct them +# as we use them. The real point is to prevent reading any more from the tied +# hash then we have to, which should hopefully alleviate speed problems. +# Caching is just an incidental detail I throw in because it makes sense. + +sub getById { + my $self = shift; + my $id = shift; + + if (defined ($self->{RESOURCE_CACHE}->{$id})) + { + return $self->{RESOURCE_CACHE}->{$id}; } - return $b; + + # resource handles inserting itself into cache. + return Apache::lonnavmaps::resource->new($self, $id); } -# --------------------------------------------------------------------- Parmval +=pod -# -------------------------------------------- Figure out a cascading parameter -# -# For this function to work -# -# * parmhash needs to be tied -# * courseopt and useropt need to be initialized for this user and course -# +=item * B(): Returns a resource object reference corresponding to the first resource in the navmap. + +=cut +sub firstResource { + my $self = shift; + my $firstResource = $self->navhash('map_start_' . + &Apache::lonnet::clutter($ENV{'request.course.uri'})); + return $self->getById($firstResource); +} + +=pod + +=item * B(): Returns a resource object reference corresponding to the last resource in the navmap. + +=cut + +sub finishResource { + my $self = shift; + my $firstResource = $self->navhash('map_finish_' . + &Apache::lonnet::clutter($ENV{'request.course.uri'})); + return $self->getById($firstResource); +} + +# Parmval reads the parm hash and cascades the lookups. parmval_real does +# the actual lookup; parmval caches the results. sub parmval { + my $self = shift; my ($what,$symb)=@_; + my $hashkey = $what."|||".$symb; + + if (defined($self->{PARM_CACHE}->{$hashkey})) { + return $self->{PARM_CACHE}->{$hashkey}; + } + + my $result = $self->parmval_real($what, $symb); + $self->{PARM_CACHE}->{$hashkey} = $result; + return $result; +} + +sub parmval_real { + my $self = shift; + my ($what,$symb) = @_; + my $cid=$ENV{'request.course.id'}; my $csec=$ENV{'request.course.sec'}; my $uname=$ENV{'user.name'}; @@ -119,585 +1265,1375 @@ sub parmval { my $courselevelr=$usercourseprefix.'.'.$symbparm; my $courselevelm=$usercourseprefix.'.'.$mapparm; + my $useropt = $self->{USER_OPT}; + my $courseopt = $self->{COURSE_OPT}; + my $parmhash = $self->{PARM_HASH}; + # ---------------------------------------------------------- first, check user - if ($uname) { - if ($useropt{$courselevelr}) { return $useropt{$courselevelr}; } - if ($useropt{$courselevelm}) { return $useropt{$courselevelm}; } - if ($useropt{$courselevel}) { return $useropt{$courselevel}; } + if ($uname and defined($useropt)) { + if (defined($$useropt{$courselevelr})) { return $$useropt{$courselevelr}; } + if (defined($$useropt{$courselevelm})) { return $$useropt{$courselevelm}; } + if (defined($$useropt{$courselevel})) { return $$useropt{$courselevel}; } } # ------------------------------------------------------- second, check course - if ($csec) { - if ($courseopt{$seclevelr}) { return $courseopt{$seclevelr}; } - if ($courseopt{$seclevelm}) { return $courseopt{$seclevelm}; } - if ($courseopt{$seclevel}) { return $courseopt{$seclevel}; } + if ($csec and defined($courseopt)) { + if (defined($$courseopt{$seclevelr})) { return $$courseopt{$seclevelr}; } + if (defined($$courseopt{$seclevelm})) { return $$courseopt{$seclevelm}; } + if (defined($$courseopt{$seclevel})) { return $$courseopt{$seclevel}; } } - if ($courseopt{$courselevelr}) { return $courseopt{$courselevelr}; } - if ($courseopt{$courselevelm}) { return $courseopt{$courselevelm}; } - if ($courseopt{$courselevel}) { return $courseopt{$courselevel}; } + if (defined($courseopt)) { + if (defined($$courseopt{$courselevelr})) { return $$courseopt{$courselevelr}; } + if (defined($$courseopt{$courselevelm})) { return $$courseopt{$courselevelm}; } + if (defined($$courseopt{$courselevel})) { return $$courseopt{$courselevel}; } + } # ----------------------------------------------------- third, check map parms - my $thisparm=$parmhash{$symbparm}; - if ($thisparm) { return $thisparm; } + my $thisparm=$$parmhash{$symbparm}; + if (defined($thisparm)) { return $thisparm; } # ----------------------------------------------------- fourth , check default my $default=&Apache::lonnet::metadata($fn,$rwhat.'.default'); - if ($default) { return $default} + if (defined($default)) { return $default} # --------------------------------------------------- fifth , cascade up parts my ($space,@qualifier)=split(/\./,$rwhat); my $qualifier=join('.',@qualifier); unless ($space eq '0') { - my ($part,$id)=split(/\_/,$space); - if ($id) { - my $partgeneral=&parmval($part.".$qualifier",$symb); - if ($partgeneral) { return $partgeneral; } - } else { - my $resourcegeneral=&parmval("0.$qualifier",$symb); - if ($resourcegeneral) { return $resourcegeneral; } - } + my ($part,$id)=split(/\_/,$space); + if ($id) { + my $partgeneral=$self->parmval($part.".$qualifier",$symb); + if (defined($partgeneral)) { return $partgeneral; } + } else { + my $resourcegeneral=$self->parmval("0.$qualifier",$symb); + if (defined($resourcegeneral)) { return $resourcegeneral; } + } } return ''; } +1; + +package Apache::lonnavmaps::iterator; + +=pod + +=back + +=head1 navmap Iterator + +An I encapsulates the logic required to traverse a data structure. navmap uses an iterator to traverse the course map according to the criteria you wish to use. + +To obtain an iterator, call the B() function of a B object. (Do not instantiate Apache::lonnavmaps::iterator directly.) This will return a reference to the iterator: + +CgetIterator();> + +To get the next thing from the iterator, call B: + +Cnext()> + +getIterator behaves as follows: -# ------------------------------------------------------------- Find out status -# return codes -# tcode (timecode) -# 1: will open later -# 2: is open and not past due yet -# 3: is past due date -# 4: due in the next 24 hours -# -# code (curent solved status) -# 1: not attempted -# 2: attempted but wrong, or incorrect by instructor -# 3: solved or correct by instructor -# "excused" needs to be supported, but is not yet. Could be code=4. -sub astatus { - my $rid=shift; - my $code=1; - my $ctext=''; - $rid=~/(\d+)\.(\d+)/; - my $symb=&Apache::lonnet::declutter($hash{'map_id_'.$1}).'___'.$2.'___'. - &Apache::lonnet::declutter($hash{'src_'.$rid}); - $Apache::lonxml::debug=1; - my %duedate=(); - my %opendate=(); - my %answerdate=(); - # need to always check part 0's open/due/answer status - foreach (sort(split(/\,/,&Apache::lonnet::metadata($hash{'src_'.$rid},'keys')))) { - if ($_=~/^parameter\_(.*)\_opendate$/) { - my $part=$1; - $duedate{$part}=&parmval($part.'.duedate',$symb); - $opendate{$part}=&parmval($part.'.opendate',$symb); - $answerdate{$part}=&parmval($part.'.answerdate',$symb); - } - } - my $now=time; - my $tcode=0; - - my %returnhash=&Apache::lonnet::restore($symb); - - foreach (sort(keys(%opendate))) { - my $duedate=$duedate{$_}; - my $opendate=$opendate{$_}; - my $answerdate=$answerdate{$_}; - my $preface=''; - unless ($_ eq '0') { $preface=' Part: '.$_.' '; } - if ($opendate) { - if ($now<$duedate || (!$duedate)) { - unless ($tcode==4) { $tcode=2; } - if ($duedate) { - $ctext.=$preface.'Due: '.localtime($duedate); - } else { - $ctext.=$preface.'No Due Date'; - } - if ($now<$opendate) { - unless ($tcode) { $tcode=1; } - $ctext.=$preface.'Open: '.localtime($opendate); - } - if ($duedate && $duedate-$now<86400) { - $tcode=4; - $ctext.=$preface.'Due: '.localtime($duedate); - } - } else { - unless (($tcode==4) || ($tcode eq 2)) { $tcode=3; } - if ($now<$answerdate) { - $ctext.='Answer: '.localtime($duedate); - } - } - } else { - unless (($tcode==2) || ($tcode==4)) { $tcode=1; } - } - - my $status=$returnhash{'resource.'.$_.'.solved'}; - - if ($status eq 'correct_by_student') { - unless ($code==2) { $code=3; } - $ctext.=' solved'; - } elsif ($status eq 'correct_by_override') { - unless ($code==2) { $code=3; } - $ctext.=' override'; - } elsif ($status eq 'incorrect_attempted') { - $code=2; - $ctext.=' ('. - ($returnhash{'resource.'.$_.'.tries'}? - $returnhash{'resource.'.$_.'.tries'}:'0'); - my $numtries = &parmval($_.'.maxtries',$symb); - if ($numtries) { $ctext.='/'.$numtries.' tries'; } - $ctext.=')'; - } elsif ($status eq 'incorrect_by_override') { - $code=2; - $ctext.=' override'; - } elsif ($status eq 'excused') { - unless ($code==2) { $code=3; } - $ctext.=' excused'; - } - } - - return 'p'.$code.$tcode.'"'.$ctext.'"'; -} - -# ------------------------------------------------------------ Build page table - -sub tracetable { - my ($sofar,$rid,$beenhere)=@_; - my $further=$sofar; - unless ($beenhere=~/\&$rid\&/) { - $beenhere.=$rid.'&'; - - if (defined($hash{'is_map_'.$rid})) { - $sofar++; - my $tprefix=''; - if ($hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$rid}}} - eq 'sequence') { - $tprefix='h'; - } - if (defined($rows[$sofar])) { - $rows[$sofar].='&'.$tprefix.$rid; - } else { - $rows[$sofar]=$tprefix.$rid; - } - if ((defined($hash{'map_start_'.$hash{'src_'.$rid}})) && - (defined($hash{'map_finish_'.$hash{'src_'.$rid}})) && - ($tprefix eq 'h')) { - my $frid=$hash{'map_finish_'.$hash{'src_'.$rid}}; - $sofar= - &tracetable($sofar,$hash{'map_start_'.$hash{'src_'.$rid}}, - '&'.$frid.'&'); - $sofar++; - if ($hash{'src_'.$frid}) { - my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$frid}); - if (($brepriv eq '2') || ($brepriv eq 'F')) { - my $pprefix=''; - if ($hash{'src_'.$frid}=~ - /\.(problem|exam|quiz|assess|survey|form)$/) { - $pprefix=&astatus($frid); - - } - if (defined($rows[$sofar])) { - $rows[$sofar].='&'.$pprefix.$frid; - } else { - $rows[$sofar]=$pprefix.$frid; - } - } - } - } - } else { - $sofar++; - if ($hash{'src_'.$rid}) { - my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$rid}); - if (($brepriv eq '2') || ($brepriv eq 'F')) { - my $pprefix=''; - if ($hash{'src_'.$rid}=~ - /\.(problem|exam|quiz|assess|survey|form)$/) { - $pprefix=&astatus($rid); - } - if (defined($rows[$sofar])) { - $rows[$sofar].='&'.$pprefix.$rid; - } else { - $rows[$sofar]=$pprefix.$rid; - } - } - } - } - - if (defined($hash{'to_'.$rid})) { - my $mincond=1; - my $next=''; - foreach (split(/\,/,$hash{'to_'.$rid})) { - my $thiscond= - &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}}); - if ($thiscond>=$mincond) { - if ($next) { - $next.=','.$_.':'.$thiscond; - } else { - $next=$_.':'.$thiscond; - } - if ($thiscond>$mincond) { $mincond=$thiscond; } - } - } - foreach (split(/\,/,$next)) { - my ($linkid,$condval)=split(/\:/,$_); - if ($condval>=$mincond) { - my $now=&tracetable($sofar,$hash{'goesto_'.$linkid},$beenhere); - if ($now>$further) { $further=$now; } - } - } +=over 4 + +=item * B(firstResource, finishResource, filterHash, condition, forceTop): All parameters are optional. firstResource is a resource reference corresponding to where the iterator should start. It defaults to navmap->firstResource() for the corresponding nav map. finishResource corresponds to where you want the iterator to end, defaulting to navmap->finishResource(). filterHash is a hash used as a set containing strings representing the resource IDs, defaulting to empty. Condition is a 1 or 0 that sets what to do with the filter hash: If a 0, then only resource that exist IN the filterHash will be recursed on. If it is a 1, only resources NOT in the filterHash will be recursed on. Defaults to 0. forceTop is a boolean value. If it is false (default), the iterator will only return the first level of map that is not just a single, 'redirecting' map. If true, the iterator will return all information, starting with the top-level map, regardless of content. + +Thus, by default, only top-level resources will be shown. Change the condition to a 1 without changing the hash, and all resources will be shown. Changing the condition to 1 and including some values in the hash will allow you to selectively suppress parts of the navmap, while leaving it on 0 and adding things to the hash will allow you to selectively add parts of the nav map. See the handler code for examples. + +The iterator will return either a reference to a resource object, or a token representing something in the map, such as the beginning of a new branch. The possible tokens are: + +=over 4 + +=item * BEGIN_MAP: A new map is being recursed into. This is returned I the map resource itself is returned. + +=item * END_MAP: The map is now done. + +=item * BEGIN_BRANCH: A branch is now starting. The next resource returned will be the first in that branch. + +=item * END_BRANCH: The branch is now done. + +=back + +The tokens are retreivable via methods on the iterator object, i.e., $iterator->END_MAP. + +Maps can contain empty resources. The iterator will automatically skip over such resources, but will still treat the structure correctly. Thus, a complicated map with several branches, but consisting entirely of empty resources except for one beginning or ending resource, will cause a lot of BRANCH_STARTs and BRANCH_ENDs, but only one resource will be returned. + +=back + +=cut + +# Here are the tokens for the iterator: + +sub BEGIN_MAP { return 1; } # begining of a new map +sub END_MAP { return 2; } # end of the map +sub BEGIN_BRANCH { return 3; } # beginning of a branch +sub END_BRANCH { return 4; } # end of a branch +sub FORWARD { return 1; } # go forward +sub BACKWARD { return 2; } + +sub min { + (my $a, my $b) = @_; + if ($a < $b) { return $a; } else { return $b; } +} - } +# In the CVS repository, documentation of this algorithm is included +# in /doc/lonnavdocs, as a PDF and .tex source. Markers like **1** +# will reference the same location in the text as the part of the +# algorithm is running through. + +sub new { + # magic invocation to create a class instance + my $proto = shift; + my $class = ref($proto) || $proto; + my $self = {}; + + $self->{NAV_MAP} = shift; + return undef unless ($self->{NAV_MAP}); + + # Handle the parameters + $self->{FIRST_RESOURCE} = shift || $self->{NAV_MAP}->firstResource(); + $self->{FINISH_RESOURCE} = shift || $self->{NAV_MAP}->finishResource(); + + # If the given resources are just the ID of the resource, get the + # objects + if (!ref($self->{FIRST_RESOURCE})) { $self->{FIRST_RESOURCE} = + $self->{NAV_MAP}->getById($self->{FIRST_RESOURCE}); } + if (!ref($self->{FINISH_RESOURCE})) { $self->{FINISH_RESOURCE} = + $self->{NAV_MAP}->getById($self->{FINISH_RESOURCE}); } + + $self->{FILTER} = shift; + + # A hash, used as a set, of resource already seen + $self->{ALREADY_SEEN} = shift; + if (!defined($self->{ALREADY_SEEN})) { $self->{ALREADY_SEEN} = {} }; + $self->{CONDITION} = shift; + + # Do we want to automatically follow "redirection" maps? + $self->{FORCE_TOP} = shift; + + # Now, we need to pre-process the map, by walking forward and backward + # over the parts of the map we're going to look at. + + # The processing steps are exactly the same, except for a few small + # changes, so I bundle those up in the following list of two elements: + # (direction_to_iterate, VAL_name, next_resource_method_to_call, + # first_resource). + # This prevents writing nearly-identical code twice. + my @iterations = ( [FORWARD(), 'TOP_DOWN_VAL', 'getNext', + 'FIRST_RESOURCE'], + [BACKWARD(), 'BOT_UP_VAL', 'getPrevious', + 'FINISH_RESOURCE'] ); + + my $maxDepth = 0; # tracks max depth + + # If there is only one resource in this map, and it's a map, we + # want to remember that, so the user can ask for the first map + # that isn't just a redirector. + my $resource; my $resourceCount = 0; + + # **1** + + foreach my $pass (@iterations) { + my $direction = $pass->[0]; + my $valName = $pass->[1]; + my $nextResourceMethod = $pass->[2]; + my $firstResourceName = $pass->[3]; + + my $iterator = Apache::lonnavmaps::DFSiterator->new($self->{NAV_MAP}, + $self->{FIRST_RESOURCE}, + $self->{FINISH_RESOURCE}, + {}, undef, 0, $direction); + + # prime the recursion + $self->{$firstResourceName}->{DATA}->{$valName} = 0; + my $depth = 0; + $iterator->next(); + my $curRes = $iterator->next(); + while ($depth > -1) { + if ($curRes == $iterator->BEGIN_MAP()) { $depth++; } + if ($curRes == $iterator->END_MAP()) { $depth--; } + + if (ref($curRes)) { + # If there's only one resource, this will save it + # we have to filter empty resources from consideration here, + # or even "empty", redirecting maps have two (start & finish) + # or three (start, finish, plus redirector) + if($direction == FORWARD && $curRes->src()) { + $resource = $curRes; $resourceCount++; + } + my $resultingVal = $curRes->{DATA}->{$valName}; + my $nextResources = $curRes->$nextResourceMethod(); + my $nextCount = scalar(@{$nextResources}); + + if ($nextCount == 1) { # **3** + my $current = $nextResources->[0]->{DATA}->{$valName} || 999999999; + $nextResources->[0]->{DATA}->{$valName} = min($resultingVal, $current); + } + + if ($nextCount > 1) { # **4** + foreach my $res (@{$nextResources}) { + my $current = $res->{DATA}->{$valName} || 999999999; + $res->{DATA}->{$valName} = min($current, $resultingVal + 1); + } + } + } + + # Assign the final val (**2**) + if (ref($curRes) && $direction == BACKWARD()) { + my $finalDepth = min($curRes->{DATA}->{TOP_DOWN_VAL}, + $curRes->{DATA}->{BOT_UP_VAL}); + + $curRes->{DATA}->{DISPLAY_DEPTH} = $finalDepth; + if ($finalDepth > $maxDepth) {$maxDepth = $finalDepth;} + } + $curRes = $iterator->next(); + } + } + + # Check: Was this only one resource, a map? + if ($resourceCount == 1 && $resource->is_map() && !$self->{FORCE_TOP}) { + my $firstResource = $resource->map_start(); + my $finishResource = $resource->map_finish(); + return + Apache::lonnavmaps::iterator->new($self->{NAV_MAP}, $firstResource, + $finishResource, $self->{FILTER}, + $self->{ALREADY_SEEN}, + $self->{CONDITION}, 0); + } - return $further; + + # Set up some bookkeeping information. + $self->{CURRENT_DEPTH} = 0; + $self->{MAX_DEPTH} = $maxDepth; + $self->{STACK} = []; + $self->{RECURSIVE_ITERATOR_FLAG} = 0; + + for (my $i = 0; $i <= $self->{MAX_DEPTH}; $i++) { + push @{$self->{STACK}}, []; + } + + # Prime the recursion w/ the first resource **5** + push @{$self->{STACK}->[0]}, $self->{FIRST_RESOURCE}; + $self->{ALREADY_SEEN}->{$self->{FIRST_RESOURCE}->{ID}} = 1; + + bless ($self); + + return $self; } -# ================================================================ Main Handler +sub next { + my $self = shift; -sub handler { - my $r=shift; + if ($self->{RECURSIVE_ITERATOR_FLAG}) { + # grab the next from the recursive iterator + my $next = $self->{RECURSIVE_ITERATOR}->next(); + + # is it a begin or end map? If so, update the depth + if ($next == BEGIN_MAP() ) { $self->{RECURSIVE_DEPTH}++; } + if ($next == END_MAP() ) { $self->{RECURSIVE_DEPTH}--; } + + # Are we back at depth 0? If so, stop recursing + if ($self->{RECURSIVE_DEPTH} == 0) { + $self->{RECURSIVE_ITERATOR_FLAG} = 0; + } + return $next; + } -# ------------------------------------------- Set document type for header only + if (defined($self->{FORCE_NEXT})) { + my $tmp = $self->{FORCE_NEXT}; + $self->{FORCE_NEXT} = undef; + return $tmp; + } - if ($r->header_only) { - if ($ENV{'browser.mathml'}) { - $r->content_type('text/xml'); - } else { - $r->content_type('text/html'); - } - $r->send_http_header; - return OK; - } - my $requrl=$r->uri; -# ----------------------------------------------------------------- Tie db file - if ($ENV{'request.course.fn'}) { - my $fn=$ENV{'request.course.fn'}; - if (-e "$fn.db") { - if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER,0640)) && - (tie(%parmhash,'GDBM_File', - $ENV{'request.course.fn'}.'_parms.db',&GDBM_READER,0640))) { -# ------------------------------------------------------------------- Hash tied - my $firstres=$hash{'map_start_/res/'.$ENV{'request.course.uri'}}; - my $lastres=$hash{'map_finish_/res/'.$ENV{'request.course.uri'}}; - if (($firstres) && ($lastres)) { -# ----------------------------------------------------------------- Render page -# -------------------------------------------------------------- Set parameters - - -# ---------------------------- initialize coursedata and userdata for this user - undef %courseopt; - undef %useropt; + # Have we not yet begun? If not, return BEGIN_MAP and + # remember we've started. + if ( !$self->{STARTED} ) { + $self->{STARTED} = 1; + return $self->BEGIN_MAP(); + } - my $uname=$ENV{'user.name'}; - my $udom=$ENV{'user.domain'}; - my $uhome=$ENV{'user.home'}; - my $cid=$ENV{'request.course.id'}; - my $chome=$ENV{'course.'.$cid.'.home'}; - my ($cdom,$cnum)=split(/\_/,$cid); + # Here's the guts of the iterator. + + # Find the next resource, if any. + my $found = 0; + my $i = $self->{MAX_DEPTH}; + my $newDepth; + my $here; + while ( $i >= 0 && !$found ) { + if ( scalar(@{$self->{STACK}->[$i]}) > 0 ) { # **6** + $here = pop @{$self->{STACK}->[$i]}; # **7** + $found = 1; + $newDepth = $i; + } + $i--; + } - my $userprefix=$uname.'_'.$udom.'_'; + # If we still didn't find anything, we're done. + if ( !$found ) { + # We need to get back down to the correct branch depth + if ( $self->{CURRENT_DEPTH} > 0 ) { + $self->{CURRENT_DEPTH}--; + return END_BRANCH(); + } else { + return END_MAP(); + } + } - unless ($uhome eq 'no_host') { -# -------------------------------------------------------------- Get coursedata - unless - ((time-$courserdatas{$cid.'.last_cache'})<240) { - my $reply=&Apache::lonnet::reply('dump:'.$cdom.':'.$cnum. - ':resourcedata',$chome); - if ($reply!~/^error\:/) { - $courserdatas{$cid}=$reply; - $courserdatas{$cid.'.last_cache'}=time; - } - } - foreach (split(/\&/,$courserdatas{$cid})) { - my ($name,$value)=split(/\=/,$_); - $courseopt{$userprefix.&Apache::lonnet::unescape($name)}= - &Apache::lonnet::unescape($value); - } -# --------------------------------------------------- Get userdata (if present) - unless - ((time-$userrdatas{$uname.'___'.$udom.'.last_cache'})<240) { - my $reply= - &Apache::lonnet::reply('dump:'.$udom.':'.$uname.':resourcedata',$uhome); - if ($reply!~/^error\:/) { - $userrdatas{$uname.'___'.$udom}=$reply; - $userrdatas{$uname.'___'.$udom.'.last_cache'}=time; - } - } - foreach (split(/\&/,$userrdatas{$uname.'___'.$udom})) { - my ($name,$value)=split(/\=/,$_); - $useropt{$userprefix.&Apache::lonnet::unescape($name)}= - &Apache::lonnet::unescape($value); - } - } - - @rows=(); - - &tracetable(0,$firstres,'&'.$lastres.'&'); - if ($hash{'src_'.$lastres}) { - my $brepriv= - &Apache::lonnet::allowed('bre',$hash{'src_'.$lastres}); - if (($brepriv eq '2') || ($brepriv eq 'F')) { - $rows[$#rows+1]=''.$lastres; - } - } - -# ------------------------------------------------------------------ Page parms - - my $j; - my $i; - my $lcm=1; - my $contents=0; - -# ---------------------------------------------- Go through table to get layout - - for ($i=0;$i<=$#rows;$i++) { - if ($rows[$i]) { - $contents++; - my @colcont=split(/\&/,$rows[$i]); - $lcm*=($#colcont+1)/euclid($lcm,($#colcont+1)); - } - } - - - unless ($contents) { - $r->content_type('text/html'); - $r->send_http_header; - $r->print('Empty Map.'); - } else { - -# ------------------------------------------------------------------ Build page - - my $currenturl=$ENV{'form.postdata'}; - $currenturl=~s/^http\:\/\///; - $currenturl=~s/^[^\/]+//; - -# ---------------------------------------------------------------- Send headers - - $r->content_type('text/html'); - &Apache::loncommon::no_cache($r); - $r->send_http_header; - - my $date=localtime; - my $now=time; -# ----------------------------------------- Get email status and discussiontime - - my %emailstatus=&Apache::lonnet::dump('email_status'); - my $logouttime=$emailstatus{'logout'}; - my $courseleave= - $emailstatus{'logout_'.$ENV{'request.course.id'}}; - my $lastcheck= - ($courseleave>$logouttime?$courseleave:$logouttime); - - my %discussiontimes=&Apache::lonnet::dump( - 'discussiontimes', - $ENV{'course.'.$ENV{'request.course.id'}.'.domain'}, - $ENV{'course.'.$ENV{'request.course.id'}.'.num'}); - - my %feedback=(); - my %error=(); - foreach my $msgid ( - split(/\&/,&Apache::lonnet::reply('keys:'. - $ENV{'user.domain'}.':'. - $ENV{'user.name'}.':nohist_email', - $ENV{'user.home'}))) { - $msgid=&Apache::lonnet::unescape($msgid); - my $plain=&Apache::lonnet::unescape( - &Apache::lonnet::unescape($msgid)); - if ($plain=~/(Error|Feedback) \[([^\]]+)\]/) { - my ($what,$url)=($1,$2); - my %status= - &Apache::lonnet::get('email_status',[$msgid]); - if ($status{$msgid}=~/^error\:/) { - $status{$msgid}=''; - } - - if (($status{$msgid} eq 'new') || - (!$status{$msgid})) { - if ($what eq 'Error') { - $error{$url}.=','.$msgid; - } else { - $feedback{$url}.=','.$msgid; - } - } - } - } -# ----------------------------------------------------------- Start Page Output - $r->print( - 'Navigate LON-CAPA Maps'); - $r->print('print(' onLoad="window.location.hash='. - "'curloc'".'"'); - } - $r->print('>'. - ''. - '

Navigate Course Map

'. - "

$date

"); - $r->rflush(); - $r->print( - ' New discussion since '. - localtime($lastcheck). - '
New message (click to open)

'); - if (($currenturl=~/^\/res/) && - ($currenturl!~/^\/res\/adm/)) { - $r->print('Current Location

'); - } -# ----------------------------------------------------- The little content list - for ($i=0;$i<=$#rows;$i++) { - if ($rows[$i]) { - my @colcont=split(/\&/,$rows[$i]); - my $avespan=$lcm/($#colcont+1); - for ($j=0;$j<=$#colcont;$j++) { - my $rid=$colcont[$j]; - if ($rid=~/^h(.+)/) { - $rid=$1; - $r->print( - '   '.$hash{'title_'.$rid}.'
'); - } - } - } - } -# ----------------------------------------------------------------- Start table - $r->print('

'); - for ($i=0;$i<=$#rows;$i++) { - if ($rows[$i]) { - $r->print("\n"); - my @colcont=split(/\&/,$rows[$i]); - my $avespan=$lcm/($#colcont+1); - for ($j=0;$j<=$#colcont;$j++) { - my $rid=$colcont[$j]; - my $add=''; - my $hwk=''; - my $hwke=''; - if ($rid=~/^h(.+)/) { - $rid=$1; - $add= - ''; - } - if ($rid=~/^p(\d)(\d)\"([\w\: \(\)\/\,]*)\"(.+)/) { - # sub astatus describes what code/tcode mean - my $code=$1; - my $tcode=$2; - my $ctext=$3; - $rid=$4; - if ($tcode eq '1') { - $add=''; - } - } - $hwk=''; - $hwke=''; - if ($code eq '1') { - $hwke=' ('.$ctext.')'; - } - if ($code eq '2') { - $hwk=''; - $hwke=' ('.$ctext.')'; - } - if ($code eq '3') { - $hwk=''; - $hwke=' ('.$ctext.')'; - } - } - if ($hash{'src_'.$rid} eq $currenturl) { - $add=$add.''. - '> '; - $adde= - ' <'.$adde; - } - my $src= - &Apache::lonnet::declutter($hash{'src_'.$rid}); - $rid=~/^(\d+)\.(\d+)$/; - my $symb= - &Apache::lonnet::declutter($hash{'map_id_'.$1}).'___'.$2.'___'.$src; - if ($discussiontimes{$symb}>$lastcheck) { - $adde= - ''. - $adde; - } - if ($error{$src}) { - foreach (split(/\,/,$error{$src})) { - if ($_) { - $adde= - ' ' - .$adde; - } - } - } - if ($feedback{$src}) { - foreach (split(/\,/,$feedback{$src})) { - if ($_) { - $adde= - ' ' - .$adde; - } - } - } - $r->print($add.''.$hwk. - $hash{'title_'.$rid}.$hwke.''.$adde); - } - $r->print(''); - } - } - $r->print("\n
  '; - my $adde=''; - $adde=''; - } - if ($code eq '3') { - $add=''; - } else { - $add=''; - if ($tcode eq '2') { - $add=''; - } - if ($tcode eq '4') { - $add=''; - $adde='
"); - $r->print(''); -# -------------------------------------------------------------------- End page - } -# ------------------------------------------------------------- End render page - } else { - $r->content_type('text/html'); - $r->send_http_header; - $r->print('Coursemap undefined.'); - } -# ------------------------------------------------------------------ Untie hash - unless (untie(%hash)) { - &Apache::lonnet::logthis("WARNING: ". - "Could not untie coursemap $fn (browse)."); - } - unless (untie(%parmhash)) { - &Apache::lonnet::logthis("WARNING: ". - "Could not untie parmhash (browse)."); - } -# -------------------------------------------------------------------- All done - return OK; -# ----------------------------------------------- Errors, hash could no be tied - } - } - } + # If this is not a resource, it must be an END_BRANCH marker we want + # to return directly. + if (!ref($here)) { # **8** + if ($here == END_BRANCH()) { # paranoia, in case of later extension + $self->{CURRENT_DEPTH}--; + return $here; + } + } + + # Otherwise, it is a resource and it's safe to store in $self->{HERE} + $self->{HERE} = $here; + + # Get to the right level + if ( $self->{CURRENT_DEPTH} > $newDepth ) { + push @{$self->{STACK}->[$newDepth]}, $here; + $self->{CURRENT_DEPTH}--; + return END_BRANCH(); + } + if ( $self->{CURRENT_DEPTH} < $newDepth) { + push @{$self->{STACK}->[$newDepth]}, $here; + $self->{CURRENT_DEPTH}++; + return BEGIN_BRANCH(); + } + + # If we made it here, we have the next resource, and we're at the + # right branch level. So let's examine the resource for where + # we can get to from here. + + # So we need to look at all the resources we can get to from here, + # categorize them if we haven't seen them, remember if we have a new + my $nextUnfiltered = $here->getNext(); + my $maxDepthAdded = -1; + + for (@$nextUnfiltered) { + if (!defined($self->{ALREADY_SEEN}->{$_->{ID}})) { + my $depth = $_->{DATA}->{DISPLAY_DEPTH}; + push @{$self->{STACK}->[$depth]}, $_; + $self->{ALREADY_SEEN}->{$_->{ID}} = 1; + if ($maxDepthAdded < $depth) { $maxDepthAdded = $depth; } + } + } + + # Is this the end of a branch? If so, all of the resources examined above + # led to lower levels then the one we are currently at, so we push a END_BRANCH + # marker onto the stack so we don't forget. + # Example: For the usual A(BC)(DE)F case, when the iterator goes down the + # BC branch and gets to C, it will see F as the only next resource, but it's + # one level lower. Thus, this is the end of the branch, since there are no + # more resources added to this level or above. + # We don't do this if the examined resource is the finish resource, + # because the condition given above is true, but the "END_MAP" will + # take care of things and we should already be at depth 0. + my $isEndOfBranch = $maxDepthAdded < $self->{CURRENT_DEPTH}; + if ($isEndOfBranch && $here != $self->{FINISH_RESOURCE}) { # **9** + push @{$self->{STACK}->[$self->{CURRENT_DEPTH}]}, END_BRANCH(); + } + + # That ends the main iterator logic. Now, do we want to recurse + # down this map (if this resource is a map)? + if ($self->{HERE}->is_map() && + (defined($self->{FILTER}->{$self->{HERE}->map_pc()}) xor $self->{CONDITION})) { + $self->{RECURSIVE_ITERATOR_FLAG} = 1; + my $firstResource = $self->{HERE}->map_start(); + my $finishResource = $self->{HERE}->map_finish(); + + $self->{RECURSIVE_ITERATOR} = + Apache::lonnavmaps::iterator->new($self->{NAV_MAP}, $firstResource, + $finishResource, $self->{FILTER}, + $self->{ALREADY_SEEN}, $self->{CONDITION}); + } + + # If this is a blank resource, don't actually return it. + # Should you ever find you need it, make sure to add an option to the code + # that you can use; other things depend on this behavior. + if (!$self->{HERE}->src()) { + return $self->next(); + } + + return $self->{HERE}; + +} + +=pod + +The other method available on the iterator is B, which returns an array populated with the current 'stack' of maps, as references to the resource objects. Example: This is useful when making the navigation map, as we need to check whether we are under a page map to see if we need to link directly to the resource, or to the page. The first elements in the array will correspond to the top of the stack (most inclusive map). + +=cut - $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized"; - return HTTP_NOT_ACCEPTABLE; +sub getStack { + my $self=shift; + + my @stack; + + $self->populateStack(\@stack); + + return \@stack; +} + +# Private method: Calls the iterators recursively to populate the stack. +sub populateStack { + my $self=shift; + my $stack = shift; + + push @$stack, $self->{HERE} if ($self->{HERE}); + + if ($self->{RECURSIVE_ITERATOR_FLAG}) { + $self->{RECURSIVE_ITERATOR}->populateStack($stack); + } } 1; -__END__ +package Apache::lonnavmaps::DFSiterator; +# Not documented in the perldoc: This is a simple iterator that just walks +# through the nav map and presents the resources in a depth-first search +# fashion, ignorant of conditionals, randomized resources, etc. It presents +# BEGIN_MAP and END_MAP, but does not understand branches at all. It is +# useful for pre-processing of some kind, and is in fact used by the main +# iterator that way, but that's about it. +# One could imagine merging this into the init routine of the main iterator, +# but this might as well be left seperate, since it is possible some other +# use might be found for it. - Jeremy + +# Unlike the main iterator, this DOES return all resources, even blank ones. +# The main iterator needs them to correctly preprocess the map. + +sub BEGIN_MAP { return 1; } # begining of a new map +sub END_MAP { return 2; } # end of the map +sub FORWARD { return 1; } # go forward +sub BACKWARD { return 2; } + +# Params: Nav map ref, first resource id/ref, finish resource id/ref, +# filter hash ref (or undef), already seen hash or undef, condition +# (as in main iterator), direction FORWARD or BACKWARD (undef->forward). +sub new { + # magic invocation to create a class instance + my $proto = shift; + my $class = ref($proto) || $proto; + my $self = {}; + + $self->{NAV_MAP} = shift; + return undef unless ($self->{NAV_MAP}); + + $self->{FIRST_RESOURCE} = shift || $self->{NAV_MAP}->firstResource(); + $self->{FINISH_RESOURCE} = shift || $self->{NAV_MAP}->finishResource(); + + # If the given resources are just the ID of the resource, get the + # objects + if (!ref($self->{FIRST_RESOURCE})) { $self->{FIRST_RESOURCE} = + $self->{NAV_MAP}->getById($self->{FIRST_RESOURCE}); } + if (!ref($self->{FINISH_RESOURCE})) { $self->{FINISH_RESOURCE} = + $self->{NAV_MAP}->getById($self->{FINISH_RESOURCE}); } + + $self->{FILTER} = shift; + + # A hash, used as a set, of resource already seen + $self->{ALREADY_SEEN} = shift; + if (!defined($self->{ALREADY_SEEN})) { $self->{ALREADY_SEEN} = {} }; + $self->{CONDITION} = shift; + $self->{DIRECTION} = shift || FORWARD(); + + # Flag: Have we started yet? + $self->{STARTED} = 0; + + # Should we continue calling the recursive iterator, if any? + $self->{RECURSIVE_ITERATOR_FLAG} = 0; + # The recursive iterator, if any + $self->{RECURSIVE_ITERATOR} = undef; + # Are we recursing on a map, or a branch? + $self->{RECURSIVE_MAP} = 1; # we'll manually unset this when recursing on branches + # And the count of how deep it is, so that this iterator can keep track of + # when to pick back up again. + $self->{RECURSIVE_DEPTH} = 0; + + # For keeping track of our branches, we maintain our own stack + $self->{STACK} = []; + + # Start with the first resource + if ($self->{DIRECTION} == FORWARD) { + push @{$self->{STACK}}, $self->{FIRST_RESOURCE}; + } else { + push @{$self->{STACK}}, $self->{FINISH_RESOURCE}; + } + + bless($self); + return $self; +} +sub next { + my $self = shift; + + # Are we using a recursive iterator? If so, pull from that and + # watch the depth; we want to resume our level at the correct time. + if ($self->{RECURSIVE_ITERATOR_FLAG}) { + # grab the next from the recursive iterator + my $next = $self->{RECURSIVE_ITERATOR}->next(); + + # is it a begin or end map? Update depth if so + if ($next == BEGIN_MAP() ) { $self->{RECURSIVE_DEPTH}++; } + if ($next == END_MAP() ) { $self->{RECURSIVE_DEPTH}--; } + + # Are we back at depth 0? If so, stop recursing. + if ($self->{RECURSIVE_DEPTH} == 0) { + $self->{RECURSIVE_ITERATOR_FLAG} = 0; + } + + return $next; + } + + # Is there a current resource to grab? If not, then return + # END_MAP, which will end the iterator. + if (scalar(@{$self->{STACK}}) == 0) { + return $self->END_MAP(); + } + + # Have we not yet begun? If not, return BEGIN_MAP and + # remember that we've started. + if ( !$self->{STARTED} ) { + $self->{STARTED} = 1; + return $self->BEGIN_MAP; + } + # Get the next resource in the branch + $self->{HERE} = pop @{$self->{STACK}}; + # remember that we've seen this, so we don't return it again later + $self->{ALREADY_SEEN}->{$self->{HERE}->{ID}} = 1; + + # Get the next possible resources + my $nextUnfiltered; + if ($self->{DIRECTION} == FORWARD()) { + $nextUnfiltered = $self->{HERE}->getNext(); + } else { + $nextUnfiltered = $self->{HERE}->getPrevious(); + } + my $next = []; + + # filter the next possibilities to remove things we've + # already seen. + foreach (@$nextUnfiltered) { + if (!defined($self->{ALREADY_SEEN}->{$_->{ID}})) { + push @$next, $_; + } + } + + while (@$next) { + # copy the next possibilities over to the stack + push @{$self->{STACK}}, shift @$next; + } + + # If this is a map and we want to recurse down it... (not filtered out) + if ($self->{HERE}->is_map() && + (defined($self->{FILTER}->{$self->{HERE}->map_pc()}) xor $self->{CONDITION})) { + $self->{RECURSIVE_ITERATOR_FLAG} = 1; + my $firstResource = $self->{HERE}->map_start(); + my $finishResource = $self->{HERE}->map_finish(); + + $self->{RECURSIVE_ITERATOR} = + Apache::lonnavmaps::DFSiterator->new ($self->{NAV_MAP}, $firstResource, + $finishResource, $self->{FILTER}, $self->{ALREADY_SEEN}, + $self->{CONDITION}, $self->{DIRECTION}); + } + + return $self->{HERE}; +} + +1; + +package Apache::lonnavmaps::resource; + +use Apache::lonnet; + +=pod + +=head1 Object: resource + +A resource object encapsulates a resource in a resource map, allowing easy manipulation of the resource, querying the properties of the resource (including user properties), and represents a reference that can be used as the canonical representation of the resource by lonnavmap clients like renderers. + +A resource only makes sense in the context of a navmap, as some of the data is stored in the navmap object. + +You will probably never need to instantiate this object directly. Use Apache::lonnavmap::navmap, and use the "start" method to obtain the starting resource. + +=head2 Public Members + +resource objects have a hash called DATA ($resourceRef->{DATA}) that you can store whatever you want in. This allows you to easily do two-pass algorithms without worrying about managing your own resource->data hash. + +=head2 Methods + +=over 4 + +=item * B($navmapRef, $idString): The first arg is a reference to the parent navmap object. The second is the idString of the resource itself. Very rarely, if ever, called directly. Use the nav map->getByID() method. + +=back + +=cut + +sub new { + # magic invocation to create a class instance + my $proto = shift; + my $class = ref($proto) || $proto; + my $self = {}; + + $self->{NAV_MAP} = shift; + $self->{ID} = shift; + + # Store this new resource in the parent nav map's cache. + $self->{NAV_MAP}->{RESOURCE_CACHE}->{$self->{ID}} = $self; + $self->{RESOURCE_ERROR} = 0; + + # A hash that can be used by two-pass algorithms to store data + # about this resource in. Not used by the resource object + # directly. + $self->{DATA} = {}; + + bless($self); + + return $self; +} + +# private function: simplify the NAV_HASH lookups we keep doing +# pass the name, and to automatically append my ID, pass a true val on the +# second param +sub navHash { + my $self = shift; + my $param = shift; + my $id = shift; + return $self->{NAV_MAP}->navhash($param . ($id?$self->{ID}:"")); +} + +=pod + +B + +These are methods that help you retrieve metadata about the resource: Method names are based on the fields in the compiled course representation. + +=over 4 + +=item * B: Returns a "composite title", that is equal to $res->title() if the resource has a title, and is otherwise the last part of the URL (e.g., "problem.problem"). + +=item * B: Returns true if the resource is external. + +=item * B: Returns the "goesto" value from the compiled nav map. (It is likely you want to use B instead.) + +=item * B: Returns the kind of the resource from the compiled nav map. + +=item * B: Returns true if this resource was chosen to NOT be shown to the user by the random map selection feature. In other words, this is usually false. + +=item * B: Returns true for a map if the randompick feature is being used on the map. (?) + +=item * B: Returns the source for the resource. + +=item * B: Returns the symb for the resource. + +=item * B: Returns the title of the resource. + +=item * B<to>: Returns the "to" value from the compiled nav map. (It is likely you want to use B<getNext> instead.) + +=back + +=cut + +# These info functions can be used directly, as they don't return +# resource information. +sub comesfrom { my $self=shift; return $self->navHash("comesfrom_", 1); } +sub ext { my $self=shift; return $self->navHash("ext_", 1) eq 'true:'; } +sub from { my $self=shift; return $self->navHash("from_", 1); } +sub goesto { my $self=shift; return $self->navHash("goesto_", 1); } +sub kind { my $self=shift; return $self->navHash("kind_", 1); } +sub randomout { my $self=shift; return $self->navHash("randomout_", 1); } +sub randompick { + my $self = shift; + return $self->{NAV_MAP}->{PARM_HASH}->{$self->symb . + '.0.parameter_randompick'}; +} +sub src { + my $self=shift; + return $self->navHash("src_", 1); +} +sub symb { + my $self=shift; + (my $first, my $second) = $self->{ID} =~ /(\d+).(\d+)/; + my $symbSrc = &Apache::lonnet::declutter($self->src()); + return &Apache::lonnet::declutter( + $self->navHash('map_id_'.$first)) + . '___' . $second . '___' . $symbSrc; +} +sub title { my $self=shift; return $self->navHash("title_", 1); } +sub to { my $self=shift; return $self->navHash("to_", 1); } +sub compTitle { + my $self = shift; + my $title = $self->title(); + if (!$title) { + $title = $self->src(); + $title = substr($title, rindex($title, '/') + 1); + } + return $title; +} +=pod + +B<Predicate Testing the Resource> + +These methods are shortcuts to deciding if a given resource has a given property. + +=over 4 + +=item * B<is_map>: Returns true if the resource is a map type. + +=item * B<is_problem>: Returns true if the resource is a problem type, false otherwise. (Looks at the extension on the src field; might need more to work correctly.) + +=item * B<is_page>: Returns true if the resource is a page. + +=item * B<is_problem>: Returns true if the resource is a problem. + +=item * B<is_sequence>: Returns true if the resource is a sequence. + +=back + +=cut + + +sub is_html { + my $self=shift; + my $src = $self->src(); + return ($src =~ /html$/); +} +sub is_map { my $self=shift; return defined($self->navHash("is_map_", 1)); } +sub is_page { + my $self=shift; + my $src = $self->src(); + return ($src =~ /page$/); +} +sub is_problem { + my $self=shift; + my $src = $self->src(); + return ($src =~ /problem$/); +} +sub is_sequence { + my $self=shift; + my $src = $self->src(); + return ($src =~ /sequence$/); +} + +# Private method: Shells out to the parmval in the nav map, handler parts. +sub parmval { + my $self = shift; + my $what = shift; + my $part = shift || "0"; + return $self->{NAV_MAP}->parmval($part.'.'.$what, $self->symb()); +} + +=pod + +B<Map Methods> + +These methods are useful for getting information about the map properties of the resource, if the resource is a map (B<is_map>). + +=over 4 + +=item * B<map_finish>: Returns a reference to a resource object corresponding to the finish resource of the map. + +=item * B<map_pc>: Returns the pc value of the map, which is the first number that appears in the resource ID of the resources in the map, and is the number that appears around the middle of the symbs of the resources in that map. + +=item * B<map_start>: Returns a reference to a resource object corresponding to the start resource of the map. + +=item * B<map_type>: Returns a string with the type of the map in it. + +=back + +=cut + +sub map_finish { + my $self = shift; + my $src = $self->src(); + my $res = $self->navHash("map_finish_$src", 0); + $res = $self->{NAV_MAP}->getById($res); + return $res; +} +sub map_pc { + my $self = shift; + my $src = $self->src(); + return $self->navHash("map_pc_$src", 0); +} +sub map_start { + my $self = shift; + my $src = $self->src(); + my $res = $self->navHash("map_start_$src", 0); + $res = $self->{NAV_MAP}->getById($res); + return $res; +} +sub map_type { + my $self = shift; + my $pc = $self->map_pc(); + return $self->navHash("map_type_$pc", 0); +} + + + +##### +# Property queries +##### + +# These functions will be responsible for returning the CORRECT +# VALUE for the parameter, no matter what. So while they may look +# like direct calls to parmval, they can be more then that. +# So, for instance, the duedate function should use the "duedatetype" +# information, rather then the resource object user. + +=pod + +=head2 Resource Parameters + +In order to use the resource parameters correctly, the nav map must have been instantiated with genCourseAndUserOptions set to true, so the courseopt and useropt is read correctly. Then, you can call these functions to get the relevant parameters for the resource. Each function defaults to part "0", but can be directed to another part by passing the part as the parameter. + +These methods are responsible for getting the parameter correct, not merely reflecting the contents of the GDBM hashes. As we move towards dates relative to other dates, these methods should be updated to reflect that. (Then, anybody using these methods won't have to update their code.) + +=over 4 + +=item * B<acc>: Get the Client IP/Name Access Control information. + +=item * B<answerdate>: Get the answer-reveal date for the problem. + +=item * B<duedate>: Get the due date for the problem. + +=item * B<tries>: Get the number of tries the student has used on the problem. + +=item * B<maxtries>: Get the number of max tries allowed. + +=item * B<opendate>: Get the open date for the problem. + +=item * B<sig>: Get the significant figures setting. + +=item * B<tol>: Get the tolerance for the problem. + +=item * B<tries>: Get the number of tries the user has already used on the problem. + +=item * B<type>: Get the question type for the problem. + +=item * B<weight>: Get the weight for the problem. + +=back + +=cut + +sub acc { + (my $self, my $part) = @_; + return $self->parmval("acc", $part); +} +sub answerdate { + (my $self, my $part) = @_; + # Handle intervals + if ($self->parmval("answerdate.type", $part) eq 'date_interval') { + return $self->duedate($part) + + $self->parmval("answerdate", $part); + } + return $self->parmval("answerdate", $part); +} +sub awarded { my $self = shift; return $self->queryRestoreHash('awarded', shift); } +sub duedate { + (my $self, my $part) = @_; + return $self->parmval("duedate", $part); +} +sub maxtries { + (my $self, my $part) = @_; + return $self->parmval("maxtries", $part); +} +sub opendate { + (my $self, my $part) = @_; + if ($self->parmval("opendate.type", $part) eq 'date_interval') { + return $self->duedate($part) - + $self->parmval("opendate", $part); + } + return $self->parmval("opendate"); +} +sub sig { + (my $self, my $part) = @_; + return $self->parmval("sig", $part); +} +sub tol { + (my $self, my $part) = @_; + return $self->parmval("tol", $part); +} +sub tries { + my $self = shift; + my $tries = $self->queryRestoreHash('tries', shift); + if (!defined($tries)) { return '0';} + return $tries; +} +sub type { + (my $self, my $part) = @_; + return $self->parmval("type", $part); +} +sub weight { + my $self = shift; my $part = shift; + return $self->parmval("weight", $part); +} + +# Multiple things need this +sub getReturnHash { + my $self = shift; + + if (!defined($self->{RETURN_HASH})) { + my %tmpHash = &Apache::lonnet::restore($self->symb()); + $self->{RETURN_HASH} = \%tmpHash; + } +} + +###### +# Status queries +###### + +# These methods query the status of problems. + +# If we need to count parts, this function determines the number of +# parts from the metadata. When called, it returns a reference to a list +# of strings corresponding to the parts. (Thus, using it in a scalar context +# tells you how many parts you have in the problem: +# $partcount = scalar($resource->countParts()); +# Don't use $self->{PARTS} directly because you don't know if it's been +# computed yet. + +=pod + +=head2 Resource misc + +Misc. functions for the resource. + +=over 4 + +=item * B<hasDiscussion>: Returns a false value if there has been discussion since the user last logged in, true if there has. Always returns false if the discussion data was not extracted when the nav map was constructed. + +=item * B<getFeedback>: Gets the feedback for the resource and returns the raw feedback string for the resource, or the null string if there is no feedback or the email data was not extracted when the nav map was constructed. Usually used like this: + + for (split(/\,/, $res->getFeedback())) { + my $link = &Apache::lonnet::escape($_); + ... + +and use the link as appropriate. + +=cut + +sub hasDiscussion { + my $self = shift; + return $self->{NAV_MAP}->hasDiscussion($self->symb()); +} + +sub getFeedback { + my $self = shift; + return $self->{NAV_MAP}->getFeedback($self->src()); +} + +=pod + +=item * B<parts>(): Returns a list reference containing sorted strings corresponding to each part of the problem. To count the number of parts, use the list in a scalar context, and subtract one if greater then two. (One part problems have a part 0. Multi-parts have a part 0, plus a part for each part. Filtering part 0 if you want it is up to you.) + +=item * B<countParts>(): Returns the number of parts of the problem a student can answer. Thus, for single part problems, returns 1. For multipart, it returns the number of parts in the problem, not including psuedo-part 0. Thus, B<parts> may return an array with fewer parts in it then countParts might lead you to believe. + +=back + +=cut + +sub parts { + my $self = shift; + + if ($self->ext) { return ['0']; } + + $self->extractParts(); + return $self->{PARTS}; +} + +sub countParts { + my $self = shift; + + my $parts = $self->parts(); + + if ($self->{RESOURCE_ERROR}) { + return 0; + } + + if (scalar(@{$parts}) < 2) { return 1;} + + return scalar(@{$parts}) - 1; +} + +# Private function: Extracts the parts information and saves it +sub extractParts { + my $self = shift; + + return if ($self->{PARTS}); + return if ($self->ext); + + $self->{PARTS} = []; + + # Retrieve part count, if this is a problem + if ($self->is_problem()) { + my $metadata = &Apache::lonnet::metadata($self->src(), 'allpossiblekeys'); + if (!$metadata) { + $self->{RESOURCE_ERROR} = 1; + $self->{PARTS} = []; + return; + } + + foreach (split(/\,/,$metadata)) { + if ($_ =~ /^parameter\_(.*)\_opendate$/) { + push @{$self->{PARTS}}, $1; + } + } + + + # Is this possible to do in one line? - Jeremy + my @sortedParts = sort @{$self->{PARTS}}; + $self->{PARTS} = \@sortedParts; + } + + return; +} + +=pod + +=head2 Resource Status + +Problem resources have status information, reflecting their various dates and completion statuses. + +There are two aspects to the status: the date-related information and the completion information. + +Idiomatic usage of these two methods would probably look something like + + foreach ($resource->parts()) { + my $dateStatus = $resource->getDateStatus($_); + my $completionStatus = $resource->getCompletionStatus($_); + + or + + my $status = $resource->status($_); + + ... use it here ... + } + +Which you use depends on exactly what you are looking for. The status() function has been optimized for the nav maps display and may not precisely match what you need elsewhere. + +The symbolic constants shown below can be accessed through the resource object: $res->OPEN. + +=over 4 + +=item * B<getDateStatus>($part): ($part defaults to 0). A convenience function that returns a symbolic constant telling you about the date status of the part. The possible return values are: + +=back + +B<Date Codes> + +=over 4 + +=item * B<OPEN_LATER>: The problem will be opened later. + +=item * B<OPEN>: Open and not yet due. + + +=item * B<PAST_DUE_ANSWER_LATER>: The due date has passed, but the answer date has not yet arrived. + +=item * B<PAST_DUE_NO_ANSWER>: The due date has passed and there is no answer opening date set. + +=item * B<ANSWER_OPEN>: The answer date is here. + +=item * B<NETWORK_FAILURE>: The information is unknown due to network failure. + +=back + +=cut + +# Apparently the compiler optimizes these into constants automatically +sub OPEN_LATER { return 0; } +sub OPEN { return 1; } +sub PAST_DUE_NO_ANSWER { return 2; } +sub PAST_DUE_ANSWER_LATER { return 3; } +sub ANSWER_OPEN { return 4; } +sub NOTHING_SET { return 5; } +sub NETWORK_FAILURE { return 100; } + +# getDateStatus gets the date status for a given problem part. +# Because answer date, due date, and open date are fully independent +# (i.e., it is perfectly possible to *only* have an answer date), +# we have to completely cover the 3x3 maxtrix of (answer, due, open) x +# (past, future, none given). This function handles this with a decision +# tree. Read the comments to follow the decision tree. + +sub getDateStatus { + my $self = shift; + my $part = shift; + $part = "0" if (!defined($part)); + + # Always return network failure if there was one. + return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE}); + + my $now = time(); + + my $open = $self->opendate($part); + my $due = $self->duedate($part); + my $answer = $self->answerdate($part); + + if (!$open && !$due && !$answer) { + # no data on the problem at all + # should this be the same as "open later"? think multipart. + return $self->NOTHING_SET; + } + if (!$open || $now < $open) {return $self->OPEN_LATER} + if (!$due || $now < $due) {return $self->OPEN} + if ($answer && $now < $answer) {return $self->PAST_DUE_ANSWER_LATER} + if ($answer) { return $self->ANSWER_OPEN; } + return PAST_DUE_NO_ANSWER; +} + +=pod + +B<> + +=over 4 + +=item * B<getCompletionStatus>($part): ($part defaults to 0.) A convenience function that returns a symbolic constant telling you about the completion status of the part, with the following possible results: + +=back + +B<Completion Codes> + +=over 4 + +=item * B<NOT_ATTEMPTED>: Has not been attempted at all. + +=item * B<INCORRECT>: Attempted, but wrong by student. + +=item * B<INCORRECT_BY_OVERRIDE>: Attempted, but wrong by instructor override. + +=item * B<CORRECT>: Correct or correct by instructor. + +=item * B<CORRECT_BY_OVERRIDE>: Correct by instructor override. + +=item * B<EXCUSED>: Excused. Not yet implemented. + +=item * B<NETWORK_FAILURE>: Information not available due to network failure. + +=item * B<ATTEMPTED>: Attempted, and not yet graded. + +=back + +=cut + +sub NOT_ATTEMPTED { return 10; } +sub INCORRECT { return 11; } +sub INCORRECT_BY_OVERRIDE { return 12; } +sub CORRECT { return 13; } +sub CORRECT_BY_OVERRIDE { return 14; } +sub EXCUSED { return 15; } +sub ATTEMPTED { return 16; } + +sub getCompletionStatus { + my $self = shift; + return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE}); + + my $status = $self->queryRestoreHash('solved', shift); + + # Left as seperate if statements in case we ever do more with this + if ($status eq 'correct_by_student') {return $self->CORRECT;} + if ($status eq 'correct_by_override') {return $self->CORRECT_BY_OVERRIDE; } + if ($status eq 'incorrect_attempted') {return $self->INCORRECT; } + if ($status eq 'incorrect_by_override') {return $self->INCORRECT_BY_OVERRIDE; } + if ($status eq 'excused') {return $self->EXCUSED; } + if ($status eq 'ungraded_attempted') {return $self->ATTEMPTED; } + return $self->NOT_ATTEMPTED; +} + +sub queryRestoreHash { + my $self = shift; + my $hashentry = shift; + my $part = shift; + $part = "0" if (!defined($part)); + return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE}); + + $self->getReturnHash(); + + return $self->{RETURN_HASH}->{'resource.'.$part.'.'.$hashentry}; +} + +=pod + +B<Composite Status> + +Along with directly returning the date or completion status, the resource object includes a convenience function B<status>() that will combine the two status tidbits into one composite status that can represent the status of the resource as a whole. The precise logic is documented in the comments of the status method. The following results may be returned, all available as methods on the resource object ($res->NETWORK_FAILURE): + +=over 4 + +=item * B<NETWORK_FAILURE>: The network has failed and the information is not available. + +=item * B<NOTHING_SET>: No dates have been set for this problem (part) at all. (Because only certain parts of a multi-part problem may be assigned, this can not be collapsed into "open later", as we don't know a given part will EVER be opened. For single part, this is the same as "OPEN_LATER".) + +=item * B<CORRECT>: For any reason at all, the part is considered correct. + +=item * B<EXCUSED>: For any reason at all, the problem is excused. + +=item * B<PAST_DUE_NO_ANSWER>: The problem is past due, not considered correct, and no answer date is set. + +=item * B<PAST_DUE_ANSWER_LATER>: The problem is past due, not considered correct, and an answer date in the future is set. + +=item * B<ANSWER_OPEN>: The problem is past due, not correct, and the answer is now available. + +=item * B<OPEN_LATER>: The problem is not yet open. + +=item * B<TRIES_LEFT>: The problem is open, has been tried, is not correct, but there are tries left. + +=item * B<INCORRECT>: The problem is open, and all tries have been used without getting the correct answer. + +=item * B<OPEN>: The item is open and not yet tried. + +=item * B<ATTEMPTED>: The problem has been attempted. + +=back + +=cut + +sub TRIES_LEFT { return 10; } + +sub status { + my $self = shift; + my $part = shift; + if (!defined($part)) { $part = "0"; } + my $completionStatus = $self->getCompletionStatus($part); + my $dateStatus = $self->getDateStatus($part); + + # What we have is a two-dimensional matrix with 4 entries on one + # dimension and 5 entries on the other, which we want to colorize, + # plus network failure and "no date data at all". + + if ($completionStatus == NETWORK_FAILURE) { return NETWORK_FAILURE; } + + # There are a few whole rows we can dispose of: + if ($completionStatus == CORRECT || + $completionStatus == CORRECT_BY_OVERRIDE ) { + return CORRECT; + } + + if ($completionStatus == ATTEMPTED) { + return ATTEMPTED; + } + + # If it's EXCUSED, then return that no matter what + if ($completionStatus == EXCUSED) { + return EXCUSED; + } + + if ($dateStatus == NOTHING_SET) { + return NOTHING_SET; + } + + # Now we're down to a 4 (incorrect, incorrect_override, not_attempted) + # by 4 matrix (date statuses). + + if ($dateStatus == PAST_DUE_ANSWER_LATER || + $dateStatus == PAST_DUE_NO_ANSWER ) { + return $dateStatus; + } + + if ($dateStatus == ANSWER_OPEN) { + return ANSWER_OPEN; + } + + # Now: (incorrect, incorrect_override, not_attempted) x + # (open_later), (open) + + if ($dateStatus == OPEN_LATER) { + return OPEN_LATER; + } + + # If it's WRONG... + if ($completionStatus == INCORRECT || $completionStatus == INCORRECT_BY_OVERRIDE) { + # and there are TRIES LEFT: + if ($self->tries($part) < $self->maxtries($part) || !$self->maxtries($part)) { + return TRIES_LEFT; + } + return INCORRECT; # otherwise, return orange; student can't fix this + } + + # Otherwise, it's untried and open + return OPEN; +} + +=pod + +=head2 Resource/Nav Map Navigation + +=over 4 + +=item * B<getNext>(): Retreive an array of the possible next resources after this one. Always returns an array, even in the one- or zero-element case. + +=item * B<getPrevious>(): Retreive an array of the possible previous resources from this one. Always returns an array, even in the one- or zero-element case. + +=cut + +sub getNext { + my $self = shift; + my @branches; + my $to = $self->to(); + foreach my $branch ( split(/,/, $to) ) { + my $choice = $self->{NAV_MAP}->getById($branch); + my $next = $choice->goesto(); + $next = $self->{NAV_MAP}->getById($next); + + # Don't remember it if the student doesn't have browse priviledges + # future note: this may properly belong in the client of the resource + my $browsePriv = $self->{BROWSE_PRIV}; + if (!defined($browsePriv)) { + $browsePriv = &Apache::lonnet::allowed('bre', $self->src); + $self->{BROWSE_PRIV} = $browsePriv; + } + if (!($browsePriv ne '2' && $browsePriv ne 'F')) { + push @branches, $next; + } + } + return \@branches; +} + +sub getPrevious { + my $self = shift; + my @branches; + my $from = $self->from(); + foreach my $branch ( split /,/, $from) { + my $choice = $self->{NAV_MAP}->getById($branch); + my $prev = $choice->comesfrom(); + $prev = $self->{NAV_MAP}->getById($prev); + + # Don't remember it if the student doesn't have browse priviledges + # future note: this may properly belong in the client of the resource + my $browsePriv = $self->{BROWSE_PRIV}; + if (!defined($browsePriv)) { + $browsePriv = &Apache::lonnet::allowed('bre', $self->src); + $self->{BROWSE_PRIV} = $browsePriv; + } + if (!($browsePriv ne '2' && $browsePriv ne 'F')) { + push @branches, $prev; + } + } + return \@branches; +} + +=pod + +=back + +=cut + +1; + +__END__