From c66e8ae2fdab0176f987d0057204b58fc926f488 Mon Sep 17 00:00:00 2001
From: Steve Clay <steve@mrclay.org>
Date: Thu, 29 Sep 2011 12:22:05 -0400
Subject: [PATCH] converted CVS patch from
 http://tracker.moodle.org/browse/MDL-21427

---
 course/lib.php  |   46 ++++++++++++++-
 lib/datalib.php |  168 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 206 insertions(+), 8 deletions(-)

diff --git a/course/lib.php b/course/lib.php
index 80494ee..cd4139f 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -2144,16 +2144,46 @@ function print_my_moodle() {
         error("It shouldn't be possible to see My Moodle without being logged in.");
     }
 
-    $courses  = get_my_courses($USER->id, 'visible DESC,sortorder ASC', array('summary'));
+    $coursepage = optional_param('coursepage', 0, PARAM_INT);
+    $courses  = get_my_courses($USER->id, 'visible DESC,sortorder ASC', array('summary'), false, 0, $coursepage);
     $rhosts   = array();
     $rcourses = array();
+
+    // calculate the pagination variables without remote courses
+    $totalcourses = count_my_courses();
+    $totalpages = (int) ceil($totalcourses / $CFG->coursesperpage);
     if (!empty($CFG->mnet_dispatcher_mode) && $CFG->mnet_dispatcher_mode==='strict') {
-        $rcourses = get_my_remotecourses($USER->id);
-        $rhosts   = get_my_remotehosts();
+
+        // calculate pagination variables with remote courses
+        $remotecoursepage = ($coursepage - $totalpages) + 1;
+        $remotepageoffset = $totalcourses % $CFG->coursesperpage;
+        if ($remotepageoffset == 0) {
+            $remotepageoffset = $CFG->coursesperpage;
+        }
+        $totalcourses = $totalcourses + count_my_remote_courses($USER->id);
+        $totalpages = ceil($totalcourses / $CFG->coursesperpage);
+
+        // only ask for the remote host course if this is a page that contains them
+        if ($remotecoursepage >= 0) {
+            $rcourses = get_my_remotecourses($USER->id,
+                                             $remotecoursepage,
+                                             $remotepageoffset);
+        }
+        $rhosts = get_my_remotehosts();
     }
 
     if (!empty($courses) || !empty($rcourses) || !empty($rhosts)) {
 
+        // build the HTML navigation tool to browse between the pages
+        $paginationhtml = print_paging_bar($totalcourses, $coursepage,
+            $CFG->coursesperpage, $CFG->wwwroot.'/index.php?',
+           'coursepage', false, true);
+
+        if ($totalpages > 1) {
+            // put the page navigation above the list of courses
+            echo $paginationhtml;
+        }
+
         if (!empty($courses)) {
             echo '<ul class="unlist">';
             foreach ($courses as $course) {
@@ -2173,7 +2203,15 @@ function print_my_moodle() {
             foreach ($rcourses as $course) {
                 print_remote_course($course, "100%");
             }
-        } elseif (!empty($rhosts)) {
+        }
+
+        if ($totalpages > 1) {
+            // Also put a page navigation bar below the list of courses
+            echo $paginationhtml;
+        }
+
+        // MNET remote hosts
+        if (empty($rcourses) && (!empty($rhosts))) {
             // non-IDP, we know of all the remote servers, but not courses
             foreach ($rhosts as $host) {
                 print_remote_host($host, "100%");
diff --git a/lib/datalib.php b/lib/datalib.php
index 2a96bae..2d8507c 100644
--- a/lib/datalib.php
+++ b/lib/datalib.php
@@ -773,6 +773,23 @@ function get_courses_wmanagers($categoryid=0, $sort="c.sortorder ASC", $fields=a
 }
 
 /**
+ * Calculates and returns the number of courses accessible to the logged in user
+ * This is the same as the number of records returned by get_my_courses($USER->id)
+ * @return int number of courses the user has access to
+ */
+function count_my_courses() {
+    global $USER;
+
+    if (!isset($USER->mycoursescount) || !is_int($USER->mycoursescount)) {
+        // $USER->mycoursescount is set by get_my_courses
+        unset($USER->mycoursescount);
+        get_my_courses($USER->id);
+    }
+
+    return $USER->mycoursescount;
+}
+
+/**
  * Convenience function - lists courses that a user has access to view.
  *
  * For admins and others with access to "every" course in the system, we should
@@ -803,9 +820,13 @@ function get_courses_wmanagers($categoryid=0, $sort="c.sortorder ASC", $fields=a
  * @param array $fields - names of _additional_ fields to return (also accepts a string)
  * @param bool $doanything True if using the doanything flag
  * @param int $limit Maximum number of records to return, or 0 for unlimited
+ * @param int $page (optional) Get only the courses which appear on this page of courses.
+ *                  The number of courses per page is determined by $CFG->coursesperpage
+ *                  Note that the first page is page 0! (not 1)
+ *                  Default is all courses are returned
  * @return array {@link $COURSE} of course objects
  */
-function get_my_courses($userid, $sort='visible DESC,sortorder ASC', $fields=NULL, $doanything=false,$limit=0) {
+function get_my_courses($userid, $sort='visible DESC,sortorder ASC', $fields=NULL, $doanything=false,$limit=0,$page=NULL) {
 
     global $CFG,$USER;
 
@@ -815,6 +836,10 @@ function get_my_courses($userid, $sort='visible DESC,sortorder ASC', $fields=NUL
         return(array());
     }
 
+    if (!is_null($page) && $page < 0) {
+        $page = 0;
+    }
+
     $basefields = array('id', 'category', 'sortorder',
                         'shortname', 'fullname', 'idnumber',
                         'teacher', 'teachers', 'student', 'students',
@@ -886,6 +911,25 @@ function get_my_courses($userid, $sort='visible DESC,sortorder ASC', $fields=NUL
             }
         }
         if (isset($courseids)) {
+
+            // if using pagination, cut the page out of the list of all courses
+            if (!is_null($page)) {
+                // convert back to array to operate on (could use PCRE?)
+                $visiblecoursearray = explode(',', $courseids);
+                $firstcoursetoreturn = $page * (int) $CFG->coursesperpage;
+
+                // if there are no courses on this page, return nothing
+                if ($firstcoursetoreturn >= count($visiblecoursearray)) {
+                    return array();
+                }
+
+                // copy the necessary courses and convert to a string
+                $pagedcoursearray = array_slice($visiblecoursearray,
+                                                $firstcoursetoreturn,
+                                                (int) $CFG->coursesperpage);
+                $courseids = implode(',', $pagedcoursearray);
+            }
+
             // The data massaging here MUST be kept in sync with
             // get_user_courses_bycap() so we return
             // the same...
@@ -970,6 +1014,15 @@ function get_my_courses($userid, $sort='visible DESC,sortorder ASC', $fields=NUL
     $courses_count = count($courses);
     $cacheids = NULL;
     $vcatpaths = array();
+    $visiblecoursescount = 0;
+    $firstcoursetoreturn = 0;
+    $lastcoursetoreturn = 0;
+
+    if (!is_null($page)) {
+        $firstcoursetoreturn = $page * (int) $CFG->coursesperpage;
+        $lastcoursetoreturn = $firstcoursetoreturn + (int) $CFG->coursesperpage;
+    }
+
     if ($userid === $USER->id && $courses_count < 500) {
         $cacheids = array();
     }
@@ -1043,9 +1096,28 @@ function get_my_courses($userid, $sort='visible DESC,sortorder ASC', $fields=NUL
             }
         }
         if ($cansee === true) {
-            $kcourses[$courses[$n]->id] = $courses[$n];
+            // increment the counter which is counting courses that could appear
+            // on a page (courses visible to the user)
+            $visiblecoursescount++;
+
+            // if this is a course within the page, (or pages not used) include it
+            if (is_null($page) || $visiblecoursescount >= $firstcoursetoreturn
+                && $visiblecoursescount <= $lastcoursetoreturn) {
+                $kcourses[$courses[$n]->id] = $courses[$n];
+            }
+
+            // cache this as a visible course for this user
             if (is_array($cacheids)) {
                 $cacheids[] = $courses[$n]->id;
+            } else if (!is_null($page)
+                && isset($USER->mycoursescount)
+                && count($kcourses) == $CFG->coursesperpage) {
+                // if we're not caching and are using pagination, stop looking
+                // at further courses if the total number of courses which can
+                // appear on the page has been reached
+                // unless we have not worked out how many courses the user can
+                // see in total yet ($USER->mycoursescount)
+                break;
             }
         }
     }
@@ -1060,6 +1132,11 @@ function get_my_courses($userid, $sort='visible DESC,sortorder ASC', $fields=NUL
         unset($USER->mycourses);
     }
 
+    // cache the total number of courses the user can see
+    if ($userid === $USER->id && !isset($USER->mycoursescount)) {
+        $USER->mycoursescount = $visiblecoursescount;
+    }
+
     return $kcourses;
 }
 
@@ -1460,26 +1537,109 @@ function fix_coursecategory_orphans() {
 }
 
 /**
+ * Number of courses the user is assigned to on remote hosts
+ * This is the total number of courses returned by the get_my_remotecourses()
+ * function.
+ * The result (for logged in user) is cached in $USER->myremotecoursescount.
+ * @param int $userid - the user id to count remove courses of
+ * @return int - number of remote courses
+ */
+function count_my_remote_courses($userid) {
+    global $CFG, $USER;
+
+    // return cached value for the logged in user
+    if ($USER->id == $userid && isset($USER->myremotecoursescount)) {
+        return $USER->myremotecoursescount;
+    }
+
+    $sql = "SELECT COUNT(*)
+            FROM   {$CFG->prefix}mnet_enrol_course c
+            JOIN   {$CFG->prefix}mnet_enrol_assignments a ON c.id=a.courseid
+            JOIN   {$CFG->prefix}mnet_host h        ON c.hostid=h.id
+            WHERE  a.userid={$userid}";
+
+    $countremotecourses = count_records_sql($sql);
+
+    // cache this result for the logged in user
+    if ($USER->id == $userid) {
+        $USER->myremotecoursescount = $countremotecourses;
+    }
+
+    return $countremotecourses;
+}
+
+/**
  * List of remote courses that a user has access to via MNET.
  * Works only on the IDP
  *
  * @uses $CFG, $USER
+ * @param $userid int (optional) userid to get the remote courses of default is logged in user
+ * @param $page int (optional) page, page of results clustered by $CFG->coursesperpage
+ *              default is to get all users remote courses
+ * @param $page_offset int (optional) the first page to display $CFG->coursesperpage
+ *              courses minus this value. Subsequent pages offset by this value.
  * @return array {@link $COURSE} of course objects
  */
-function get_my_remotecourses($userid=0) {
+function get_my_remotecourses($userid=0, $page=NULL, $pageoffset=NULL) {
     global $CFG, $USER;
 
     if (empty($userid)) {
         $userid = $USER->id;
     }
 
+    $limitclause = "";
+
+    // set default behaviour in the event of a bad $page to return everything
+    if (!is_null($page) && $page < 0) {
+        $page = null;
+    }
+
+    // limit the return from the query to only get the courses for the current page
+    if (!is_null($page)) {
+
+        if ($USER->id == $userid) {
+
+            // see if any remote courses exist for the logged in user
+            $countremotecourses = count_my_remote_courses($userid);
+
+            // if this user has no remote courses, quickly return an empty array
+            if ($countremotecourses < 1) {
+                return array();
+            }
+        }
+
+        if (is_null($pageoffset) || $pageoffset < 0) {
+            $pageoffset = 0;
+        }
+        if ($pageoffset > $CFG->coursesperpage) {
+            debugging("page_offset ({$pageoffset}) is set larger than coursesperpage ({$CFG->coursesperpage})");
+            $pageoffset = 0;
+        }
+
+        $limitstart = $page * $CFG->coursesperpage;
+        $limitlength = $CFG->coursesperpage;
+
+        if ($pageoffset > 0) {
+            if ($page == 0) {
+                // the first page of results is shrunk by $pageoffset
+                $limitlength = $limitlength - $pageoffset;
+            } else {
+                // subsequent pages are offset by $pageoffset
+                $limitstart = $limitstart - $pageoffset;
+            }
+        }
+
+        $limitclause = "LIMIT {$limitstart},{$limitlength}";
+    }
+
     $sql = "SELECT c.id, c.remoteid, c.shortname, c.fullname,
                    c.hostid, c.summary, c.cat_name,
                    h.name AS hostname
             FROM   {$CFG->prefix}mnet_enrol_course c
             JOIN   {$CFG->prefix}mnet_enrol_assignments a ON c.id=a.courseid
             JOIN   {$CFG->prefix}mnet_host h        ON c.hostid=h.id
-            WHERE  a.userid={$userid}";
+            WHERE  a.userid={$userid}
+            {$limitclause}";
 
     return get_records_sql($sql);
 }
-- 
1.7.5.4