[evolution] I#645 - Prefer-Plain: Hide vendor-specific subparts of multipart/alternative

[Milan Crha <mcrha src gnome org>]

commit 79f83564b7a76f0284b69b44a42d74cc86a1ce49
Author: Milan Crha <mcrha redhat com>
Date:   Mon Sep 30 15:56:26 2019 +0200

    I#645 - Prefer-Plain: Hide vendor-specific subparts of multipart/alternative
    
    Closes https://gitlab.gnome.org/GNOME/evolution/issues/645

 src/modules/prefer-plain/e-mail-parser-prefer-plain.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)
---
diff --git a/src/modules/prefer-plain/e-mail-parser-prefer-plain.c 
b/src/modules/prefer-plain/e-mail-parser-prefer-plain.c
index bce556235d..af84ef9af6 100644
--- a/src/modules/prefer-plain/e-mail-parser-prefer-plain.c
+++ b/src/modules/prefer-plain/e-mail-parser-prefer-plain.c
@@ -213,6 +213,7 @@ empe_prefer_plain_parse (EMailParserExtension *extension,
        gboolean prefer_html;
        GQueue plain_text_parts = G_QUEUE_INIT;
        GQueue work_queue = G_QUEUE_INIT;
+       GQueue attachments_queue = G_QUEUE_INIT;
 
        emp_pp = (EMailParserPreferPlain *) extension;
        prefer_html = (emp_pp->mode == PREFER_HTML);
@@ -352,17 +353,13 @@ empe_prefer_plain_parse (EMailParserExtension *extension,
 
                        has_html |= multipart_has_html;
 
-               /* Parse everything else as an attachment */
-               } else {
-                       GQueue inner_queue = G_QUEUE_INIT;
-
+               /* Parse other than 'X' (those are custom types) as an attachment */
+               } else if (ct && ct->subtype && ct->subtype[0] && ct->subtype[0] != 'x' && ct->subtype[0] != 
'X') {
                        e_mail_parser_parse_part (
                                parser, sp, part_id,
-                               cancellable, &inner_queue);
+                               cancellable, &attachments_queue);
                        e_mail_parser_wrap_as_attachment (
-                               parser, sp, part_id, &inner_queue);
-
-                       e_queue_transfer (&inner_queue, &work_queue);
+                               parser, sp, part_id, &attachments_queue);
                }
        }
 
@@ -391,6 +388,7 @@ empe_prefer_plain_parse (EMailParserExtension *extension,
        /* plain_text parts should be always first */
        e_queue_transfer (&plain_text_parts, out_mail_parts);
        e_queue_transfer (&work_queue, out_mail_parts);
+       e_queue_transfer (&attachments_queue, out_mail_parts);
 
        g_string_truncate (part_id, partidlen);