From 5e43eea080228c86370fb19ae4e767497243d5e4 Mon Sep 17 00:00:00 2001
From: Michael Aherne <michael.aherne@strath.ac.uk>
Date: Fri, 8 Jan 2016 11:09:29 +0000
Subject: [PATCH] MDL-52702 plagiarism: Improvements to base plugin class

---
 lang/en/admin.php      |  2 +-
 lib/plagiarismlib.php  |  8 +++++---
 plagiarism/lib.php     | 24 +++++++++++++++++++-----
 plagiarism/upgrade.txt |  6 ++++++
 4 files changed, 31 insertions(+), 9 deletions(-)
 create mode 100644 plagiarism/upgrade.txt

diff --git a/lang/en/admin.php b/lang/en/admin.php
index 1ecd467767c..2d2c16cc76a 100644
--- a/lang/en/admin.php
+++ b/lang/en/admin.php
@@ -1032,7 +1032,7 @@ $string['taskgradecron'] = 'Background processing for gradebook';
 $string['tasklegacycron'] = 'Legacy cron processing for plugins';
 $string['taskmessagingcleanup'] = 'Background processing for messaging';
 $string['taskpasswordresetcleanup'] = 'Cleanup password reset attempts';
-$string['taskplagiarismcron'] = 'Background processing for plagiarism plugins';
+$string['taskplagiarismcron'] = 'Background processing for legacy cron in plagiarism plugins';
 $string['taskportfoliocron'] = 'Background processing for portfolio plugins';
 $string['taskquestioncron'] = 'Background processing for question engine';
 $string['taskregistrationcron'] = 'Site registration';
diff --git a/lib/plagiarismlib.php b/lib/plagiarismlib.php
index 1c28f17b301..0492ad1aafa 100644
--- a/lib/plagiarismlib.php
+++ b/lib/plagiarismlib.php
@@ -171,12 +171,14 @@ function plagiarism_cron() {
     }
     $plagiarismplugins = plagiarism_load_available_plugins();
     foreach($plagiarismplugins as $plugin => $dir) {
-        mtrace('Processing cron function for plagiarism_plugin_' . $plugin . '...', '');
-        cron_trace_time_and_memory();
         require_once($dir.'/lib.php');
         $plagiarismclass = "plagiarism_plugin_$plugin";
         $plagiarismplugin = new $plagiarismclass;
-        $plagiarismplugin->cron();
+        if (method_exists($plagiarismplugin, 'cron')) {
+            mtrace('Processing cron function for plagiarism_plugin_' . $plugin . '...', '');
+            cron_trace_time_and_memory();
+            $plagiarismplugin->cron();
+        }
     }
 }
 /**
diff --git a/plagiarism/lib.php b/plagiarism/lib.php
index 003961a34c3..9cfd91d0bc7 100644
--- a/plagiarism/lib.php
+++ b/plagiarism/lib.php
@@ -19,8 +19,7 @@
  * lib.php - Contains Plagiarism base class used by plugins.
  *
  * @since Moodle 2.0
- * @package    moodlecore
- * @subpackage plagiarism
+ * @package    core_plagiarism
  * @copyright  2010 Dan Marsden http://danmarsden.com
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
@@ -29,8 +28,16 @@ if (!defined('MOODLE_INTERNAL')) {
     die('Direct access to this script is forbidden.');    ///  It must be included from a Moodle page
 }
 
-//dummy class - all plugins should be based off this.
-class plagiarism_plugin {
+
+/**
+ * Plagiarism base class used by plugins.
+ *
+ * @since Moodle 2.0
+ * @package    core_plagiarism
+ * @copyright  2010 Dan Marsden http://danmarsden.com
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+abstract class plagiarism_plugin {
 
     /**
      * Return the list of form element names.
@@ -90,10 +97,17 @@ class plagiarism_plugin {
      */
     public function update_status($course, $cm) {
     }
+
     /**
-     * hook for cron
+     * Deprecated cron method.
+     *
+     * This method was added by mistake in the previous versions of Moodle, do not override it since it is never called.
+     * To implement cron you need to register a scheduled task, see https://docs.moodle.org/dev/Task_API.
+     * For backward compatibility with the old cron API the method cron() from this class can also be used.
      *
+     * @deprecated since Moodle 3.1 MDL-52702 - please use scheduled tasks instead.
      */
     public function plagiarism_cron() {
+        debugging('plagiarism_plugin::plagiarism_cron() is deprecated. Please use scheduled tasks instead', DEBUG_DEVELOPER);
     }
 }
diff --git a/plagiarism/upgrade.txt b/plagiarism/upgrade.txt
new file mode 100644
index 00000000000..bc7d8a1aaa1
--- /dev/null
+++ b/plagiarism/upgrade.txt
@@ -0,0 +1,6 @@
+This files describes API changes for code that uses the plagiarism API.
+
+=== 3.1 ===
+
+1) The plagiarism_plugin::plagiarism_cron() and plagiarism_plugin::cron() methods have been deprecated.
+   Plugins should now use scheduled tasks.
\ No newline at end of file
-- 
2.17.1