[evolution-ews] Bug 771370 - Exchange 2016 returns broken MIME content for events with detached instances

[Milan Crha <mcrha src gnome org>]

commit 4940e4c24783d393aafc2dd0b02eb78a1924d8c2
Author: Milan Crha <mcrha redhat com>
Date:   Mon Sep 19 16:59:47 2016 +0200

    Bug 771370 - Exchange 2016 returns broken MIME content for events with detached instances

 src/calendar/e-cal-backend-ews.c |   32 ++++++++++++++++++++++++++++++++
 1 files changed, 32 insertions(+), 0 deletions(-)
---
diff --git a/src/calendar/e-cal-backend-ews.c b/src/calendar/e-cal-backend-ews.c
index 65430a0..ded9c57 100644
--- a/src/calendar/e-cal-backend-ews.c
+++ b/src/calendar/e-cal-backend-ews.c
@@ -3209,6 +3209,38 @@ add_item_to_cache (ECalBackendEws *cbews,
                mime_content = e_ews_item_get_mime_content (item);
                vcomp = icalparser_parse_string (mime_content);
 
+               if (!vcomp && mime_content) {
+                       const gchar *begin_vcalendar, *end_vcalendar;
+
+                       /* Workaround Exchange 2016 error, which returns invalid iCalendar object (without 
'END:VCALENDAR'),
+                          when the event has at least one detached instance. */
+                       begin_vcalendar = camel_strstrcase (mime_content, "BEGIN:VCALENDAR");
+                       end_vcalendar = camel_strstrcase (mime_content, "END:VCALENDAR");
+
+                       /* If it exists, then it should be alone on a separate line */
+                       if (!(begin_vcalendar && (begin_vcalendar == mime_content || begin_vcalendar[-1] == 
'\n') &&
+                           (begin_vcalendar[15 /* strlen ("BEGIN:VCALENDAR") */] == '\r' || 
begin_vcalendar[15] == '\n')))
+                               begin_vcalendar = NULL;
+
+                       /* If it exists, then it should be alone on a separate line and not at the very 
beginning of the mime_content */
+                       if (!(end_vcalendar && end_vcalendar > mime_content && end_vcalendar[-1] == '\n' &&
+                           (end_vcalendar[13 /* strlen ("END:VCALENDAR") */] == '\r' || end_vcalendar[13] == 
'\n' || end_vcalendar[13] == '\0')))
+                               end_vcalendar = NULL;
+
+                       if (begin_vcalendar && !end_vcalendar) {
+                               gchar *str;
+
+                               str = g_strconcat (mime_content, "\r\n", "END:VCALENDAR", "\r\n", NULL);
+                               vcomp = icalparser_parse_string (str);
+                               g_free (str);
+                       }
+               }
+
+               if (!vcomp) {
+                       g_warn_if_reached ();
+                       return;
+               }
+
                tzid = e_ews_item_get_tzid (item);
                if (tzid == NULL) {
                        /*