Plugin API: Call message_part_structure hook for sub-parts of multipart/alternative message (#5678)

CHANGELOG

@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Plugin API: Call message_part_structure hook for sub-parts of multipart/alternative message (#5678)
 - Enigma: Always use detached signatures (#5624)
 - Enigma: Fix handling of messages with nested PGP encrypted parts (#5634)
 - Minimize unwanted message loading in preview frame on drag (#5616)

program/lib/Roundcube/rcube_message.php

@@ -679,9 +679,10 @@ class rcube_message
                 $this->parse_alternative = false;
 
                 // if plain part was found, we should unset it if html is preferred
-                if ($this->opt['prefer_html'] && count($this->parts))
+                if ($this->opt['prefer_html'] && count($this->parts)) {
                     $plain_part = null;
                 }
+            }
 
             // choose html/plain part to print
             if ($html_part !== null && $this->opt['prefer_html']) {
@@ -697,8 +698,16 @@ class rcube_message
             // add the right message body
             if (is_object($print_part)) {
                 $print_part->type = 'content';
+
+                // Allow plugins to handle also this part
+                $plugin = $this->app->plugins->exec_hook('message_part_structure',
+                    array('object' => $this, 'structure' => $print_part,
+                        'mimetype' => $print_part->mimetype, 'recursive' => true));
+
+                if (!$plugin['abort']) {
                     $this->add_part($print_part);
                 }
+            }
             // show plaintext warning
             else if ($html_part !== null && empty($this->parts)) {
                 $c = new stdClass;