From 13f73be25b7e157863ed399727f9a3ccd054cfa2 Mon Sep 17 00:00:00 2001
From: Frederic Massart <fred@moodle.com>
Date: Fri, 31 May 2013 14:25:21 +0800
Subject: [PATCH] MDL-39536 completion: Prevent DB call when fetching
 activities

---
 lib/completionlib.php   | 44 +++++++++++++++++++----------------------
 report/progress/lib.php |  2 +-
 2 files changed, 21 insertions(+), 25 deletions(-)

diff --git a/lib/completionlib.php b/lib/completionlib.php
index 389312f601d..78f9eb8b62a 100644
--- a/lib/completionlib.php
+++ b/lib/completionlib.php
@@ -1045,40 +1045,36 @@ class completion_info {
         }
     }
 
+     /**
+     * Return whether or not the course has activities with completion enabled.
+     *
+     * @return boolean true when there is at least one activity with completion enabled.
+     */
+    public function has_activities() {
+        $modinfo = get_fast_modinfo($this->course);
+        foreach ($modinfo->get_cms() as $cm) {
+            if ($cm->completion != COMPLETION_TRACKING_NONE) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * Obtains a list of activities for which completion is enabled on the
      * course. The list is ordered by the section order of those activities.
      *
-     * @param array $modinfo For unit testing only, supply the value
-     *   here. Otherwise the method calls get_fast_modinfo
      * @return array Array from $cmid => $cm of all activities with completion enabled,
      *   empty array if none
      */
-    public function get_activities($modinfo=null) {
-        global $DB;
-
-        // Obtain those activities which have completion turned on
-        $withcompletion = $DB->get_records_select('course_modules', 'course='.$this->course->id.
-          ' AND completion<>'.COMPLETION_TRACKING_NONE);
-        if (!$withcompletion) {
-            return array();
-        }
-
-        // Use modinfo to get section order and also add in names
-        if (empty($modinfo)) {
-            $modinfo = get_fast_modinfo($this->course);
-        }
+    public function get_activities() {
+        $modinfo = get_fast_modinfo($this->course);
         $result = array();
-        foreach ($modinfo->sections as $sectioncms) {
-            foreach ($sectioncms as $cmid) {
-                if (array_key_exists($cmid, $withcompletion)) {
-                    $result[$cmid] = $withcompletion[$cmid];
-                    $result[$cmid]->modname = $modinfo->cms[$cmid]->modname;
-                    $result[$cmid]->name    = $modinfo->cms[$cmid]->name;
-                }
+        foreach ($modinfo->get_cms() as $cm) {
+            if ($cm->completion != COMPLETION_TRACKING_NONE) {
+                $result[$cm->id] = $cm;
             }
         }
-
         return $result;
     }
 
diff --git a/report/progress/lib.php b/report/progress/lib.php
index c8ec1e43e61..3931e714b3b 100644
--- a/report/progress/lib.php
+++ b/report/progress/lib.php
@@ -44,7 +44,7 @@ function report_progress_extend_navigation_course($navigation, $course, $context
     }
 
     $completion = new completion_info($course);
-    $showonnavigation = ($showonnavigation && $completion->is_enabled() && count($completion->get_activities())>0);
+    $showonnavigation = ($showonnavigation && $completion->is_enabled() && $completion->has_activities());
     if ($showonnavigation) {
         $url = new moodle_url('/report/progress/index.php', array('course'=>$course->id));
         $navigation->add(get_string('pluginname','report_progress'), $url, navigation_node::TYPE_SETTING, null, null, new pix_icon('i/report', ''));