--- loncom/interface/loncommon.pm	2014/12/11 01:16:33	1.1202
+++ loncom/interface/loncommon.pm	2015/03/09 19:09:34	1.1209
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # a pile of common routines
 #
-# $Id: loncommon.pm,v 1.1202 2014/12/11 01:16:33 raeburn Exp $
+# $Id: loncommon.pm,v 1.1209 2015/03/09 19:09:34 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -1757,6 +1757,241 @@ RESIZE
 
 }
 
+sub colorfuleditor_js {
+    return <<"COLORFULEDIT"
+<script type="text/javascript">
+// <![CDATA[>
+    function fold_box(curDepth, lastresource){
+
+    // we need a list because there can be several blocks you need to fold in one tag
+        var block = document.getElementsByName('foldblock_'+curDepth);
+    // but there is only one folding button per tag
+        var foldbutton = document.getElementById('folding_btn_'+curDepth);
+
+        if(block.item(0).style.display == 'none'){
+
+            foldbutton.value = '@{[&mt("Hide")]}';
+            for (i = 0; i < block.length; i++){
+                block.item(i).style.display = '';
+            }
+        }else{
+
+            foldbutton.value = '@{[&mt("Show")]}';
+            for (i = 0; i < block.length; i++){
+                // block.item(i).style.visibility = 'collapse';
+                block.item(i).style.display = 'none';
+            }
+        };
+        saveState(lastresource);
+    }
+
+    function saveState (lastresource) {
+
+        var tag_list = getTagList();
+        if(tag_list != null){
+            var timestamp = new Date().getTime();
+            var key = lastresource;
+
+            // the value pattern is: 'time;key1,value1;key2,value2; ... '
+            // starting with timestamp
+            var value = timestamp+';';
+
+            // building the list of key-value pairs
+            for(var i = 0; i < tag_list.length; i++){
+                value += tag_list[i]+',';
+                value += document.getElementsByName(tag_list[i])[0].style.display+';';
+            }
+
+            // only iterate whole storage if nothing to override
+            if(localStorage.getItem(key) == null){        
+
+                // prevent storage from growing large
+                if(localStorage.length > 50){
+                    var regex_getTimestamp = /^(?:\d)+;/;
+                    var oldest_timestamp = regex_getTimestamp.exec(localStorage.key(0));
+                    var oldest_key;
+                    
+                    for(var i = 1; i < localStorage.length; i++){
+                        if (regex_getTimestamp.exec(localStorage.key(i)) < oldest_timestamp) {
+                            oldest_key = localStorage.key(i);
+                            oldest_timestamp = regex_getTimestamp.exec(oldest_key);
+                        }
+                    }
+                    localStorage.removeItem(oldest_key);
+                }
+            }
+            localStorage.setItem(key,value);
+        }
+    }
+
+    // restore folding status of blocks (on page load)
+    function restoreState (lastresource) {
+        if(localStorage.getItem(lastresource) != null){
+            var key = lastresource;
+            var value = localStorage.getItem(key);
+            var regex_delTimestamp = /^\d+;/;
+
+            value.replace(regex_delTimestamp, '');
+
+            var valueArr = value.split(';');
+            var pairs;
+            var elements;
+            for (var i = 0; i < valueArr.length; i++){
+                pairs = valueArr[i].split(',');
+                elements = document.getElementsByName(pairs[0]);
+
+                for (var j = 0; j < elements.length; j++){  
+                    elements[j].style.display = pairs[1];
+                    if (pairs[1] == "none"){
+                        var regex_id = /([_\\d]+)\$/;
+                        regex_id.exec(pairs[0]);
+                        document.getElementById("folding_btn"+RegExp.\$1).value = "Show";
+                    }
+                }
+            }
+        }
+    }
+
+    function getTagList () {
+        
+        var stringToSearch = document.lonhomework.innerHTML;
+
+        var ret = new Array();
+        var regex_findBlock = /(foldblock_.*?)"/g;
+        var tag_list = stringToSearch.match(regex_findBlock);
+
+        if(tag_list != null){
+            for(var i = 0; i < tag_list.length; i++){            
+                ret.push(tag_list[i].replace(/"/, ''));
+            }
+        }
+        return ret;
+    }
+
+    function saveScrollPosition (resource) {
+        var tag_list = getTagList();
+
+        // we dont always want to jump to the first block
+        // 170 is roughly above the "Problem Editing" header. we just want to save if the user scrolled down further than this
+        if(\$(window).scrollTop() > 170){
+            if(tag_list != null){
+                var result;
+                for(var i = 0; i < tag_list.length; i++){
+                    if(isElementInViewport(tag_list[i])){
+                        result += tag_list[i]+';';
+                    }
+                }
+                sessionStorage.setItem('anchor_'+resource, result);
+            }
+        } else {
+            // we dont need to save zero, just delete the item to leave everything tidy
+            sessionStorage.removeItem('anchor_'+resource);
+        }
+    }
+
+    function restoreScrollPosition(resource){
+
+        var elem = sessionStorage.getItem('anchor_'+resource);
+        if(elem != null){
+            var tag_list = elem.split(';');
+            var elem_list;
+
+            for(var i = 0; i < tag_list.length; i++){
+                elem_list = document.getElementsByName(tag_list[i]);
+                
+                if(elem_list.length > 0){
+                    elem = elem_list[0];
+                    break;
+                }
+            }
+            elem.scrollIntoView();
+        }
+    }
+
+    function isElementInViewport(el) {
+
+        // change to last element instead of first
+        var elem = document.getElementsByName(el);
+        var rect = elem[0].getBoundingClientRect();
+
+        return (
+            rect.top >= 0 &&
+            rect.left >= 0 &&
+            rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) && /*or $(window).height() */
+            rect.right <= (window.innerWidth || document.documentElement.clientWidth) /*or $(window).width() */
+        );
+    }
+    
+    function autosize(depth){
+        var cmInst = window['cm'+depth];
+        var fitsizeButton = document.getElementById('fitsize'+depth);
+
+        // is fixed size, switching to dynamic
+        if (sessionStorage.getItem("autosized_"+depth) == null) {
+            cmInst.setSize("","auto");
+            fitsizeButton.value = "@{[&mt('Fixed size')]}";
+            sessionStorage.setItem("autosized_"+depth, "yes");
+
+        // is dynamic size, switching to fixed
+        } else {
+            cmInst.setSize("","300px");
+            fitsizeButton.value = "@{[&mt('Dynamic size')]}";
+            sessionStorage.removeItem("autosized_"+depth);
+        }
+    }
+
+
+
+// ]]>
+</script>
+COLORFULEDIT
+}
+
+sub xmleditor_js {
+    return <<XMLEDIT
+<script type="text/javascript" src="/adm/jQuery/addons/jquery-scrolltofixed.js"></script>
+<script type="text/javascript">
+// <![CDATA[>
+
+    function saveScrollPosition (resource) {
+
+        var scrollPos = \$(window).scrollTop();
+        sessionStorage.setItem(resource,scrollPos);
+    }
+
+    function restoreScrollPosition(resource){
+
+        var scrollPos = sessionStorage.getItem(resource);
+        \$(window).scrollTop(scrollPos);
+    }
+
+    // unless internet explorer
+    if (!(window.navigator.appName == "Microsoft Internet Explorer" && (document.documentMode || document.compatMode))){
+
+        \$(document).ready(function() {
+             \$(".LC_edit_actionbar").scrollToFixed(\{zIndex: 100\});
+        });
+    }
+
+    // inserts text at cursor position into codemirror (xml editor only)
+    function insertText(text){
+        cm.focus();
+        var curPos = cm.getCursor();
+        cm.replaceRange(text.replace(/ESCAPEDSCRIPT/g,'script'), {line: curPos.line,ch: curPos.ch});
+    }
+// ]]>
+</script>
+XMLEDIT
+}
+
+sub insert_folding_button {
+    my $curDepth = $Apache::lonxml::curdepth;
+    my $lastresource = $env{'request.ambiguous'};
+
+    return "<input type=\"button\" id=\"folding_btn_$curDepth\" 
+            value=\"".&mt('Hide')."\" onclick=\"fold_box('$curDepth','$lastresource')\">";
+}
+
 =pod
 
 =head1 Excel and CSV file utility routines
@@ -4841,23 +5076,29 @@ sub get_domainconf {
             if (keys(%{$domconfig{'login'}})) {
                 foreach my $key (keys(%{$domconfig{'login'}})) {
                     if (ref($domconfig{'login'}{$key}) eq 'HASH') {
-                        if ($key eq 'loginvia') {
-                            if (ref($domconfig{'login'}{'loginvia'}) eq 'HASH') {
-                                foreach my $hostname (keys(%{$domconfig{'login'}{'loginvia'}})) {
-                                    if (ref($domconfig{'login'}{'loginvia'}{$hostname}) eq 'HASH') {
-                                        if ($domconfig{'login'}{'loginvia'}{$hostname}{'server'}) {
-                                            my $server = $domconfig{'login'}{'loginvia'}{$hostname}{'server'};
-                                            $designhash{$udom.'.login.loginvia'} = $server;
-                                            if ($domconfig{'login'}{'loginvia'}{$hostname}{'serverpath'} eq 'custom') {
-
-                                                $designhash{$udom.'.login.loginvia_'.$hostname} = $server.':'.$domconfig{'login'}{'loginvia'}{$hostname}{'custompath'};
-                                            } else {
-                                                $designhash{$udom.'.login.loginvia_'.$hostname} = $server.':'.$domconfig{'login'}{'loginvia'}{$hostname}{'serverpath'};
+                        if (($key eq 'loginvia') || ($key eq 'headtag')) {
+                            if (ref($domconfig{'login'}{$key}) eq 'HASH') {
+                                foreach my $hostname (keys(%{$domconfig{'login'}{$key}})) {
+                                    if (ref($domconfig{'login'}{$key}{$hostname}) eq 'HASH') {
+                                        if ($key eq 'loginvia') {
+                                            if ($domconfig{'login'}{'loginvia'}{$hostname}{'server'}) {
+                                                my $server = $domconfig{'login'}{'loginvia'}{$hostname}{'server'};
+                                                $designhash{$udom.'.login.loginvia'} = $server;
+                                                if ($domconfig{'login'}{'loginvia'}{$hostname}{'serverpath'} eq 'custom') {
+
+                                                    $designhash{$udom.'.login.loginvia_'.$hostname} = $server.':'.$domconfig{'login'}{'loginvia'}{$hostname}{'custompath'};
+                                                } else {
+                                                    $designhash{$udom.'.login.loginvia_'.$hostname} = $server.':'.$domconfig{'login'}{'loginvia'}{$hostname}{'serverpath'};
+                                                }
                                             }
-                                            if ($domconfig{'login'}{'loginvia'}{$hostname}{'exempt'}) {
-                                                $designhash{$udom.'.login.loginvia_exempt_'.$hostname} = $domconfig{'login'}{'loginvia'}{$hostname}{'exempt'};
+                                        } elsif ($key eq 'headtag') {
+                                            if ($domconfig{'login'}{'headtag'}{$hostname}{'url'}) {
+                                                $designhash{$udom.'.login.headtag_'.$hostname} = $domconfig{'login'}{'headtag'}{$hostname}{'url'};
                                             }
                                         }
+                                        if ($domconfig{'login'}{$key}{$hostname}{'exempt'}) {
+                                            $designhash{$udom.'.login.'.$key.'_exempt_'.$hostname} = $domconfig{'login'}{$key}{$hostname}{'exempt'};
+                                        }
                                     }
                                 }
                             }
@@ -6555,6 +6796,7 @@ div.LC_edit_problem_footer div,
 div.LC_edit_problem_editxml_header,
 div.LC_edit_problem_editxml_header div {
   margin-top: 5px;
+  z-index: 100;
 }
 
 div.LC_edit_problem_header_title {
@@ -6572,7 +6814,12 @@ table.LC_edit_problem_header_title {
 
 div.LC_edit_problem_discards {
   float: left;
-  padding-bottom: 5px;
+}
+
+div.LC_edit_actionbar {
+    margin: -5px 0px 0px 0px !important;
+    background-color: $sidebg;
+    height: 31px;
 }
 
 div.LC_edit_problem_saves {
@@ -6593,6 +6840,10 @@ div.LC_edit_problem_saves {
     margin-left: 40px;
 }
 
+#LC_edit_problem_codemirror div{
+    margin-left: 0px;
+}
+
 img.stift {
   border-width: 0;
   vertical-align: middle;
@@ -6707,7 +6958,6 @@ fieldset > legend {
 ol.LC_primary_menu {
   margin: 0;
   padding: 0;
-  background-color: $pgbg_or_bgcolor;
 }
 
 ol#LC_PathBreadcrumbs {
@@ -6719,23 +6969,48 @@ ol.LC_primary_menu li {
   vertical-align: middle;
   text-align: left;
   list-style: none;
+  position: relative;
   float: left;
+  z-index: 100; /* will be displayed above codemirror and underneath the help-layer */
+  line-height: 1.5em;
 }
 
-ol.LC_primary_menu li a {
+ol.LC_primary_menu li a,
+ol.LC_primary_menu li p {
   display: block;
   margin: 0;
   padding: 0 5px 0 10px;
   text-decoration: none;
 }
 
-ol.LC_primary_menu li ul {
+ol.LC_primary_menu li p span.LC_primary_menu_innertitle {
+  display: inline-block;
+  width: 95%;
+  text-align: left;
+}
+
+ol.LC_primary_menu li p span.LC_primary_menu_innerarrow {
+  display: inline-block;	
+  width: 5%;
+  float: right;
+  text-align: right;
+  font-size: 70%;
+}
+
+ol.LC_primary_menu ul {
   display: none;
-  width: 10em;
+  width: 15em;
   background-color: $data_table_light;
+  position: absolute;
+  top: 100%;
+}
+
+ol.LC_primary_menu ul ul {
+  left: 100%;
+  top: 0;
 }
 
-ol.LC_primary_menu li:hover ul, ol.LC_primary_menu li.hover ul {
+ol.LC_primary_menu li:hover > ul, ol.LC_primary_menu li.hover > ul {
   display: block;
   position: absolute;
   margin: 0;
@@ -6744,15 +7019,21 @@ ol.LC_primary_menu li:hover ul, ol.LC_pr
 }
 
 ol.LC_primary_menu li:hover li, ol.LC_primary_menu li.hover li {
+/* First Submenu -> size should be smaller than the menu title of the whole menu */
   font-size: 90%;
   vertical-align: top;
   float: none;
   border-left: 1px solid black;
   border-right: 1px solid black;
+/* A dark bottom border to visualize different menu options; 
+overwritten in the create_submenu routine for the last border-bottom of the menu */
+  border-bottom: 1px solid $data_table_dark; 
 }
 
-ol.LC_primary_menu li:hover li a, ol.LC_primary_menu li.hover li a {
-  background-color:$data_table_light;
+ol.LC_primary_menu li li p:hover {
+  color:$button_hover;
+  text-decoration:none;
+  background-color:$data_table_dark;
 }
 
 ol.LC_primary_menu li li a:hover {
@@ -6760,6 +7041,11 @@ ol.LC_primary_menu li li a:hover {
    background-color:$data_table_dark;
 }
 
+/* Font-size equal to the size of the predecessors*/
+ol.LC_primary_menu li:hover li li {
+  font-size: 100%;
+}
+
 ol.LC_primary_menu li img {
   vertical-align: bottom;
   height: 1.1em;
@@ -7733,10 +8019,12 @@ function set_wishlistlink(title, path) {
         title = title.replace(/^LON-CAPA /,'');
     }
     title = encodeURIComponent(title);
+    title = title.replace("'","\\\'");
     if (!path) {
         path = location.pathname;
     }
     path = encodeURIComponent(path);
+    path = path.replace("'","\\\'");
     Win = window.open('/adm/wishlist?mode=newLink&setTitle='+title+'&setPath='+path,
                       'wishlistNewLink','width=560,height=350,scrollbars=0');
 }
@@ -7779,12 +8067,13 @@ var modalWindow = {
 };
 	var openMyModal = function(source,width,height,scrolling,transparency,style)
 	{
+                source = source.replace("'","&#39;");
 		modalWindow.windowId = "myModal";
 		modalWindow.width = width;
 		modalWindow.height = height;
 		modalWindow.content = "<iframe width='"+width+"' height='"+height+"' frameborder='0' scrolling='"+scrolling+"' allowtransparency='"+transparency+"' src='" + source + "' style='"+style+"'></iframe>";
 		modalWindow.open();
-	};	
+	};
 // END LON-CAPA Internal -->
 // ]]>
 </script>
@@ -11198,7 +11487,6 @@ function camtasiaToggle() {
     for (var i=0; i<document.uploaded_decompress.autoextract_camtasia.length; i++) {
         if (document.uploaded_decompress.autoextract_camtasia[i].checked) {
             if (document.uploaded_decompress.autoextract_camtasia[i].value == $is_camtasia) {
-
                 document.getElementById('camtasia_titles').style.display='block';
             } else {
                 document.getElementById('camtasia_titles').style.display='none';
@@ -14552,7 +14840,7 @@ sub escape_url {
     my ($url)   = @_;
     my @urlslices = split(/\//, $url,-1);
     my $lastitem = &escape(pop(@urlslices));
-    return join('/',@urlslices).'/'.$lastitem;
+    return &HTML::Entities::encode(join('/',@urlslices),"'").'/'.$lastitem;
 }
 
 sub compare_arrays {
@@ -14610,6 +14898,17 @@ sub init_user_environment {
 		}
 	    }
 	    closedir(DIR);
+# If there is a undeleted lockfile for the user's paste buffer remove it.
+            my $namespace = 'nohist_courseeditor';
+            my $lockingkey = 'paste'."\0".'locked_num';
+            my %lockhash = &Apache::lonnet::get($namespace,[$lockingkey],
+                                                $domain,$username);
+            if (exists($lockhash{$lockingkey})) {
+                my $delresult = &Apache::lonnet::del($namespace,[$lockingkey],$domain,$username);
+                unless ($delresult eq 'ok') {
+                    &Apache::lonnet::logthis("Failed to delete paste buffer locking key in $namespace for ".$username.":".$domain." Result was: $delresult");
+                }
+            }
 	}
 # Give them a new cookie
 	my $id = ($args->{'robot'} ? 'robot'.$args->{'robot'}
@@ -15330,8 +15629,206 @@ sub search_courses {
 
 =back
 
+=head1 Routines for version requirements for current course.
+
+=over 4
+
+=item * &check_release_required()
+
+Compares required LON-CAPA version with version on server, and
+if required version is newer looks for a server with the required version.
+
+Looks first at servers in user's owen domain; if none suitable, looks at
+servers in course's domain are permitted to host sessions for user's domain.
+
+Inputs:
+
+$loncaparev - Version on current server (format: Major.Minor.Subrelease-datestamp)
+
+$courseid - Course ID of current course
+
+$rolecode - User's current role in course (for switchserver query string).
+
+$required - LON-CAPA version needed by course (format: Major.Minor).
+
+
+Returns:
+
+$switchserver - query string tp append to /adm/switchserver call (if 
+                current server's LON-CAPA version is too old. 
+
+$warning - Message is displayed if no suitable server could be found.
+
+=cut
+
+sub check_release_required {
+    my ($loncaparev,$courseid,$rolecode,$required) = @_;
+    my ($switchserver,$warning);
+    if ($required ne '') {
+        my ($reqdmajor,$reqdminor) = ($required =~ /^(\d+)\.(\d+)$/);
+        my ($major,$minor) = ($loncaparev =~ /^\'?(\d+)\.(\d+)\.[\w.\-]+\'?$/);
+        if ($reqdmajor ne '' && $reqdminor ne '') {
+            my $otherserver;
+            if (($major eq '' && $minor eq '') ||
+                (($reqdmajor > $major) || (($reqdmajor == $major) && ($reqdminor > $minor)))) {
+                my ($userdomserver) = &Apache::lonnet::choose_server($env{'user.domain'},undef,$required,1);
+                my $switchlcrev =
+                    &Apache::lonnet::get_server_loncaparev($env{'user.domain'},
+                                                           $userdomserver);
+                my ($swmajor,$swminor) = ($switchlcrev =~ /^\'?(\d+)\.(\d+)\.[\w.\-]+\'?$/);
+                if (($swmajor eq '' && $swminor eq '') || ($reqdmajor > $swmajor) ||
+                    (($reqdmajor == $swmajor) && ($reqdminor > $swminor))) {
+                    my $cdom = $env{'course.'.$courseid.'.domain'};
+                    if ($cdom ne $env{'user.domain'}) {
+                        my ($coursedomserver,$coursehostname) = &Apache::lonnet::choose_server($cdom,undef,$required,1);
+                        my $serverhomeID = &Apache::lonnet::get_server_homeID($coursehostname);
+                        my $serverhomedom = &Apache::lonnet::host_domain($serverhomeID);
+                        my %defdomdefaults = &Apache::lonnet::get_domain_defaults($serverhomedom);
+                        my %udomdefaults = &Apache::lonnet::get_domain_defaults($env{'user.domain'});
+                        my $remoterev = &Apache::lonnet::get_server_loncaparev($serverhomedom,$coursedomserver);
+                        my $canhost =
+                            &Apache::lonnet::can_host_session($env{'user.domain'},
+                                                              $coursedomserver,
+                                                              $remoterev,
+                                                              $udomdefaults{'remotesessions'},
+                                                              $defdomdefaults{'hostedsessions'});
+
+                        if ($canhost) {
+                            $otherserver = $coursedomserver;
+                        } else {
+                            $warning = &mt('Requires LON-CAPA version [_1].',$env{'course.'.$courseid.'.internal.releaserequired'}).'<br />'. &mt("No suitable server could be found amongst servers in either your own domain or in the course's domain.");
+                        }
+                    } else {
+                        $warning = &mt('Requires LON-CAPA version [_1].',$env{'course.'.$courseid.'.internal.releaserequired'}).'<br />'.&mt("No suitable server could be found amongst servers in your own domain (which is also the course's domain).");
+                    }
+                } else {
+                    $otherserver = $userdomserver;
+                }
+            }
+            if ($otherserver ne '') {
+                $switchserver = 'otherserver='.$otherserver.'&amp;role='.$rolecode;
+            }
+        }
+    }
+    return ($switchserver,$warning);
+}
+
+=pod
+
+=item * &check_release_result()
+
+Inputs:
+
+$switchwarning - Warning message if no suitable server found to host session.
+
+$switchserver - query string to append to /adm/switchserver containing lonHostID
+                and current role.
+
+Returns: HTML to display with information about requirement to switch server.
+         Either displaying warning with link to Roles/Courses screen or
+         display link to switchserver.
+
+=cut
+
+sub check_release_result {
+    my ($switchwarning,$switchserver) = @_;
+    my $output = &start_page('Selected course unavailable on this server').
+                 '<p class="LC_warning">';
+    if ($switchwarning) {
+        $output .= $switchwarning.'<br /><a href="/adm/roles">';
+        if (&show_course()) {
+            $output .= &mt('Display courses');
+        } else {
+            $output .= &mt('Display roles');
+        }
+        $output .= '</a>';
+    } elsif ($switchserver) {
+        $output .= &mt('This course requires a newer version of LON-CAPA than is installed on this server.').
+                   '<br />'.
+                   '<a href="/adm/switchserver?'.$switchserver.'">'.
+                   &mt('Switch Server').
+                   '</a>';
+    }
+    $output .= '</p>'.&end_page();
+    return $output;
+}
+
+=pod
+
+=item * &needs_coursereinit()
+
+Determine if course contents stored for user's session needs to be
+refreshed, because content has changed since "Big Hash" last tied.
+
+Check for change is made if time last checked is more than 10 minutes ago
+(by default).
+
+Inputs:
+
+$loncaparev - Version on current server (format: Major.Minor.Subrelease-datestamp)
+
+$interval (optional) - Time which may elapse (in s) between last check for content
+                       change in current course. (default: 600 s).  
+
+Returns: an array; first element is:
+
+=over 4
+
+'switch' - if content updates mean user's session
+           needs to be switched to a server running a newer LON-CAPA version
+ 
+'update' - if course session needs to be refreshed (i.e., Big Hash needs to be reloaded)
+           on current server hosting user's session                
+
+''       - if no action required.
+
+=back
+
+If first item element is 'switch':
+
+second item is $switchwarning - Warning message if no suitable server found to host session. 
+
+third item is $switchserver - query string to append to /adm/switchserver containing lonHostID
+                              and current role. 
+
+otherwise: no other elements returned.
+
+=back
+
 =cut
 
+sub needs_coursereinit {
+    my ($loncaparev,$interval) = @_;
+    return() unless ($env{'request.course.id'} && $env{'request.course.tied'});
+    my $cdom = $env{'course.'.$env{'request.course.id'}.'.domain'};
+    my $cnum = $env{'course.'.$env{'request.course.id'}.'.num'};
+    my $now = time;
+    if ($interval eq '') {
+        $interval = 600;
+    }
+    if (($now-$env{'request.course.timechecked'})>$interval) {
+        my $lastchange = &Apache::lonnet::get_coursechange($cdom,$cnum);
+        &Apache::lonnet::appenv({'request.course.timechecked'=>$now});
+        if ($lastchange > $env{'request.course.tied'}) {
+            my %curr_reqd_hash = &Apache::lonnet::userenvironment($cdom,$cnum,'internal.releaserequired');
+            if ($curr_reqd_hash{'internal.releaserequired'} ne '') {
+                my $required = $env{'course.'.$cdom.'_'.$cnum.'.internal.releaserequired'};
+                if ($curr_reqd_hash{'internal.releaserequired'} ne $required) {
+                    &Apache::lonnet::appenv({'course.'.$cdom.'_'.$cnum.'.internal.releaserequired' =>
+                                             $curr_reqd_hash{'internal.releaserequired'}});
+                    my ($switchserver,$switchwarning) =
+                        &check_release_required($loncaparev,$cdom.'_'.$cnum,$env{'request.role'},
+                                                $curr_reqd_hash{'internal.releaserequired'});
+                    if ($switchwarning ne '' || $switchserver ne '') {
+                        return ('switch',$switchwarning,$switchserver);
+                    }
+                }
+            }
+            return ('update');
+        }
+    }
+    return ();
+}
 
 sub update_content_constraints {
     my ($cdom,$cnum,$chome,$cid) = @_;