[evolution] Bug #540269 - Do not crash in em_format_is_attachment

[Milan Crha <mcrha src gnome org>]

commit b9149e4e89d6fc56505b75de1e3e0c13dada4b3e
Author: Milan Crha <mcrha redhat com>
Date:   Wed May 27 15:15:28 2009 +0200

    Bug #540269 - Do not crash in em_format_is_attachment
    
    Check if part contains data wrapper before accessing its members.
---
 mail/em-format.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/mail/em-format.c b/mail/em-format.c
index b2360bb..83f0d4a 100644
--- a/mail/em-format.c
+++ b/mail/em-format.c
@@ -991,6 +991,9 @@ int em_format_is_attachment(EMFormat *emf, CamelMimePart *part)
 	/*CamelContentType *ct = camel_mime_part_get_content_type(part);*/
 	CamelDataWrapper *dw = camel_medium_get_content_object((CamelMedium *)part);
 
+	if (!dw)
+		return 0;
+
 	/*printf("checking is attachment %s/%s\n", ct->type, ct->subtype);*/
 	return !(camel_content_type_is (dw->mime_type, "multipart", "*")
 		 || camel_content_type_is(dw->mime_type, "application", "x-pkcs7-mime")