imapc: Filter out X-Message-Flag: header from incoming mails.

This is only added by MS Exchange when \Flagged flag is set, so it could be
made optional, but it probably doesn't really hurt to just make it
unconditional to ease the configuration.

diff --git a/src/lib-storage/index/imapc/imapc-mail-fetch.c b/src/lib-storage/index/imapc/imapc-mail-fetch.c
index 1958d848c7eff2ec39c7c67f09f1ecd08bd110d1..a33c8085a1ade29295624a5452e5f7a59163c6be 100644 (file)
--- a/src/lib-storage/index/imapc/imapc-mail-fetch.c
+++ b/src/lib-storage/index/imapc/imapc-mail-fetch.c
@@ -3,6 +3,7 @@
 #include "lib.h"
 #include "str.h"
 #include "istream.h"
+#include "istream-header-filter.h"
 #include "imap-arg.h"
 #include "imap-date.h"
 #include "imapc-client.h"
@@ -182,6 +183,23 @@ static bool imapc_find_lfile_arg(const struct imapc_untagged_reply *reply,
        return FALSE;
 }
 
+static void imapc_stream_filter(struct istream **input)
+{
+       static const char *imapc_hide_headers[] = {
+               /* Added by MS Exchange 2010 when \Flagged flag is set.
+                  This violates IMAP guarantee of messages being immutable. */
+               "X-Message-Flag"
+       };
+       struct istream *filter_input;
+
+       filter_input = i_stream_create_header_filter(*input,
+               HEADER_FILTER_EXCLUDE,
+               imapc_hide_headers, N_ELEMENTS(imapc_hide_headers),
+               null_header_filter_callback, NULL);
+       i_stream_unref(input);
+       *input = filter_input;
+}
+
 static void
 imapc_fetch_stream(struct imapc_mail *mail,
                   const struct imapc_untagged_reply *reply,
@@ -230,6 +248,7 @@ imapc_fetch_stream(struct imapc_mail *mail,
                          t_strdup_printf("imapc mail uid=%u", _mail->uid));
        index_mail_set_read_buffer_size(_mail, imail->data.stream);
 
+       imapc_stream_filter(&imail->data.stream);
        if (imail->mail.v.istream_opened != NULL) {
                if (imail->mail.v.istream_opened(_mail,
                                                 &imail->data.stream) < 0) {