From 9dc01fba7c4f659e89a36427321fcf8c613bbd1a Mon Sep 17 00:00:00 2001
From: Gareth Barnard <1058419+gjb2048@users.noreply.github.com>
Date: Fri, 12 Nov 2021 21:09:24 +0000
Subject: [PATCH] Purge the caches and lock protection - #114.

---
 classes/activity.php       | 11 +++++++++++
 lang/en/format_topcoll.php |  4 ++--
 settings.php               |  8 ++++++--
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/classes/activity.php b/classes/activity.php
index 4ee93254..e3b718f1 100644
--- a/classes/activity.php
+++ b/classes/activity.php
@@ -595,8 +595,11 @@ protected static function course_participant_count($courseid, $mod) {
         // New users?
         $usercreatedcache = \cache::make('format_topcoll', 'activityusercreatedcache');
         $createdusers = $usercreatedcache->get($courseid);
+        $lock = null;
         $newstudents = array();
         if (!empty($createdusers)) {
+            $lock = self::lockcaches($courseid);
+
             $studentrolescache = \cache::make('format_topcoll', 'activitystudentrolescache');
             $studentroles = $studentrolescache->get('roles');
             $context = \context_course::instance($courseid);
@@ -653,9 +656,17 @@ protected static function course_participant_count($courseid, $mod) {
                 $modulecountcache->set($courseid, $modulecountcourse);
             }
 
+            if (!is_null($lock)) {
+                $lock->release();
+            }
+
             return $modulecountcourse[$mod->id][0];
         }
 
+        if (!is_null($lock)) {
+            $lock->release();
+        }
+
         return 0;
     }
 
diff --git a/lang/en/format_topcoll.php b/lang/en/format_topcoll.php
index f3ae6229..1a534015 100644
--- a/lang/en/format_topcoll.php
+++ b/lang/en/format_topcoll.php
@@ -118,7 +118,7 @@
 
 // Coursesetting - Show addtional data for modules.
 $string['enableadditionalmoddata'] = 'Enable additional information';
-$string['enableadditionalmoddatadesc'] = 'This is a \'Site level\' switch to turn the activity information on or off.  It needs to be \'on\' for the related settings that operate at a course level to take effect.  As this functionality can be computationally expensive, then it is strongly suggested that you undertake full testing before using on a production system.';
+$string['enableadditionalmoddatadesc'] = 'This is a \'Site level\' switch to turn the activity information on or off.  It needs to be \'on\' for the related settings that operate at a course level to take effect.  As this functionality can be computationally expensive, then it is strongly suggested that you undertake full testing before using on a production system.  Note: Purges the cache caches when changed.';
 
 $string['showadditionalmoddata'] = 'Show additional information for: {$a} in the course';
 $string['showadditionalmoddata_help'] = 'Allow all users to see the activity deadline and users with grading permission to see the number of submissions on the course page for activities.';
@@ -130,7 +130,7 @@
 $string['resetallactivitymeta_help'] = 'Resets all the additional module information to follow the site default value.';
 
 $string['courseadditionalmoddatamaxstudents'] = 'Set the maximum number of students on a course that \'Show additional information\' will apply to';
-$string['courseadditionalmoddatamaxstudentsdesc'] = 'Additional information can take time to calculate, especially on large courses, so here you can set the maximum number of students that a couse can have for the functionality to show on that course.  Above that value, the \'Additional information\' will NOT be calculated or show regardless of the course settings!  A value of \'0\' means \'unlimited\'.';
+$string['courseadditionalmoddatamaxstudentsdesc'] = 'Additional information can take time to calculate, especially on large courses, so here you can set the maximum number of students that a couse can have for the functionality to show on that course.  Above that value, the \'Additional information\' will NOT be calculated or show regardless of the course settings!  A value of \'0\' means \'unlimited\'.  Note: Purges the cache caches when changed.';
 
 $string['courseadditionalmoddatastudentsinfo'] = 'Additional information status:';
 $string['courseadditionalmoddatastudentsinfounlimited'] = 'Additional information will show for the enabled activities for {$a} students.';
diff --git a/settings.php b/settings.php
index 77c1c76d..934778a2 100644
--- a/settings.php
+++ b/settings.php
@@ -516,13 +516,17 @@
         1 => new lang_string('no'),
         2 => new lang_string('yes')
     );
-    $settings->add(new admin_setting_configselect($name, $title, $description, $default, $choices));
+    $setting = new admin_setting_configselect($name, $title, $description, $default, $choices);
+    $setting->set_updatedcallback('cache_helper::purge_all');
+    $settings->add($setting);
 
     $name = 'format_topcoll/courseadditionalmoddatamaxstudents';
     $title = get_string('courseadditionalmoddatamaxstudents', 'format_topcoll');
     $description = get_string('courseadditionalmoddatamaxstudentsdesc', 'format_topcoll');
     $default = 0;
-    $settings->add(new admin_setting_configtext($name, $title, $description, $default, PARAM_INT));
+    $setting = new admin_setting_configtext($name, $title, $description, $default, PARAM_INT);
+    $setting->set_updatedcallback('cache_helper::purge_all');
+    $settings->add($setting);
 
     $name = 'format_topcoll/defaultshowadditionalmoddata';
     $title = get_string('defaultshowadditionalmoddata', 'format_topcoll');