MDL-29548 allow message plugins to control message

defaults.

At the moment, each message_provider can specify defaults for
each message output, to say whether that message output should be
used for this type of message:
http://docs.moodle.org/dev/Messaging_2.0#Adding_new_message_type.

If the message provider does not set a default, this change allows
the message output to set the default.

message/lib.php

@@ -2308,6 +2308,34 @@ function get_message_processors($ready = false) {
     return $processors;
 }
 
+/**
+ * Get an instance of the message_output class for one of the output plugins.
+ * @param string $type the message output type. E.g. 'email' or 'jabber'.
+ * @return message_output message_output the requested class.
+ */
+function get_message_processor($type) {
+    global $CFG;
+
+    // Note, we cannot use the get_message_processors function here, becaues this
+    // code is called during install after installing each messaging plugin, and
+    // get_message_processors caches the list of installed plugins.
+
+    $processorfile = $CFG->dirroot . "/message/output/{$type}/message_output_{$type}.php";
+    if (!is_readable($processorfile)) {
+        throw new coding_exception('Unknown message processor type ' . $type);
+    }
+
+    include_once($processorfile);
+
+    $processclass = 'message_output_' . $type;
+    if (!class_exists($processclass)) {
+        throw new coding_exception('Message processor ' . $type .
+                ' does not define the right class');
+    }
+
+    return new $processclass();
+}
+
 /**
  * Get messaging outputs default (site) preferences
  *
@@ -2345,11 +2373,8 @@ function translate_message_default_setting($plugindefault, $processorname) {
     );
 
     // define the default setting
-    if ($processorname == 'email') {
-        $default = MESSAGE_PERMITTED + MESSAGE_DEFAULT_LOGGEDIN + MESSAGE_DEFAULT_LOGGEDOFF;
-    } else {
-        $default = MESSAGE_PERMITTED;
-    }
+    $processor = get_message_processor($processorname);
+    $default = $processor->get_default_messaging_settings();
 
     // Validate the value. It should not exceed the maximum size
     if (!is_int($plugindefault) || ($plugindefault > 0x0f)) {

message/output/email/message_output_email.php

@@ -88,6 +88,15 @@ class message_output_email extends message_output {
         }
     }
 
+    /**
+     * @return int the Default message output settings for this output, for
+     * message providers that do not specify what the settings should be for
+     * this output in the messages.php file.
+     */
+    public function get_default_messaging_settings() {
+        return MESSAGE_PERMITTED + MESSAGE_DEFAULT_LOGGEDIN + MESSAGE_DEFAULT_LOGGEDOFF;
+    }
+
     /**
      * Loads the config data from database to put on the form (initial load)
      * @param array $preferences preferences array

message/output/lib.php

@@ -55,6 +55,14 @@ abstract class message_output {
         return true;
     }
 
+    /**
+     * @return int the Default message output settings for this output, for
+     * message providers that do not specify what the settings should be for
+     * this output in the messages.php file.
+     */
+    public function get_default_messaging_settings() {
+        return MESSAGE_PERMITTED;
+    }
 }