# Small patch to Cyrus IMAP 2.1.16 which modifies \Seen state handling to
# make it compatible with Outlook Express. OE makes two connections to a
# given mailfolder: one generates indexes while the other fetches messages.
# Unfortunately it gets confused if \Seen updates caused by the message
# stream aren't immediately flushed and picked up by the index stream.
#
# Apparently Mozilla Thunderbird has the same problem.
#
diff -ur cyrus-imapd-2.1.16-DIST/imap/imapd.c cyrus-imapd-2.1.16/imap/imapd.c
--- cyrus-imapd-2.1.16-DIST/imap/imapd.c	2003-09-24 15:16:02.000000000 +0100
+++ cyrus-imapd-2.1.16/imap/imapd.c	2005-04-04 10:26:46.399575348 +0100
@@ -2991,6 +2991,10 @@
     index_fetch(imapd_mailbox, sequence, usinguid, &fetchargs,
 		&fetchedsomething);
 
+    /* Checkpoint \Seen immediately after each FETCH completes. Checks for
+     * changes from other processes at the same time */
+    index_check_existing(imapd_mailbox, usinguid, 1);  
+
     if (fetchedsomething || usinguid) {
 	prot_printf(imapd_out, "%s OK %s\r\n", tag,
 		    error_message(IMAP_OK_COMPLETED));
@@ -3108,7 +3112,8 @@
 
     index_fetch(imapd_mailbox, msgno, 0, &fetchargs, &fetchedsomething);
 
-    index_check(imapd_mailbox, 0, 0);
+    /* Vanilla index_check() can generate illegal EXPUNGE events */
+    index_check_existing(imapd_mailbox, 0, 1);
 
     if (fetchedsomething) {
 	prot_printf(imapd_out, "%s OK %s\r\n", tag,
@@ -3245,7 +3250,9 @@
 		    flag, nflags);
 
     if (usinguid) {
-	index_check(imapd_mailbox, 1, 0);
+	index_check(imapd_mailbox, 1, 1);   /* Check \Seen too */
+    } else {
+        index_check_existing(imapd_mailbox, 0, 1);
     }
 
     if (r) {
diff -ur cyrus-imapd-2.1.16-DIST/imap/imapd.h cyrus-imapd-2.1.16/imap/imapd.h
--- cyrus-imapd-2.1.16-DIST/imap/imapd.h	2003-02-13 20:15:25.000000000 +0000
+++ cyrus-imapd-2.1.16/imap/imapd.h	2005-04-04 11:10:13.482298858 +0100
@@ -240,6 +240,8 @@
 extern void index_operatemailbox(struct mailbox *mailbox);
 extern void index_check(struct mailbox *mailbox, int usinguid,
 			   int checkseen);
+extern void
+index_check_existing(struct mailbox *mailbox, int usinguid, int checkseen);
 extern void index_checkseen(struct mailbox *mailbox, int quiet,
 			       int usinguid, int oldexists);
 
diff -ur cyrus-imapd-2.1.16-DIST/imap/index.c cyrus-imapd-2.1.16/imap/index.c
--- cyrus-imapd-2.1.16-DIST/imap/index.c	2003-08-14 17:20:32.000000000 +0100
+++ cyrus-imapd-2.1.16/imap/index.c	2005-04-04 10:28:20.764246213 +0100
@@ -422,6 +422,45 @@
     }
 }
 
+/* Nasty hack to report system + user flags updates without checking for
+ * new mail or expunge (relies on index atomic rewrite+rename for expunge).
+ *
+ * Needed to keep Outlook Express happy without breaking IMAP concurrent
+ * access regime which (quite correctly) prohibits unsolicited EXPUNGE and
+ * EXIST responses for non-UID versions of FETCH and STORE. Otherwise you
+ * can end up with hilarous situations such as:
+ *
+ *   . FETCH 2 fast
+ *   * EXPUNGE 1          <-- from concurrent session.
+ *   . FETCH (data relating to previous message _3_, if it exists)
+ *
+ */
+
+void
+index_check_existing(struct mailbox *mailbox, int usinguid, int checkseen)
+{
+    int msgno, i;
+    bit32 user_flags[MAX_USER_FLAGS/32];
+
+    if (imapd_exists == -1)
+        return;
+
+    /* Bail out if the mailbox was rotated under our feet */
+    if ((index_len > 0) &&
+        ((stat(FNAME_INDEX+1, &sbuf) != 0) ||
+         (sbuf.st_ino != mailbox->index_ino) ||
+	 (index_ino != mailbox->index_ino)))
+        return;
+
+    if (checkseen)
+        index_checkseen(mailbox, 0, usinguid, imapd_exists);
+
+    for (msgno = 1; msgno <= imapd_exists; msgno++) {
+	if (flagreport[msgno] < LAST_UPDATED(msgno)) {
+	    for (i = 0; i < VECTOR_SIZE(user_flags); i++) {
+		user_flags[i] = USER_FLAGS(msgno, i);
+	    }
+	    index_fetchflags(mailbox, msgno, SYSTEM_FLAGS(msgno), user_flags,
+			     LAST_UPDATED(msgno));
+	    if (usinguid) prot_printf(imapd_out, " UID %u", UID(msgno));
+	    prot_printf(imapd_out, ")\r\n");
+	}
+    }
+}
+
 /*
  * Checkpoint the user's \Seen state
  *
@@ -455,6 +494,7 @@
     char *saveseenuids, *save;
     int savealloced;
     unsigned start, newallseen, inrange, usecomma;
+    mailbox_notifyproc_t *updatenotifier;
 
     if (!keepingseen || !seendb) return;
     if (imapd_exists == 0) {
@@ -728,6 +768,9 @@
 
     free(newseenuids);
     seenuids = saveseenuids;
+
+    updatenotifier = mailbox_get_updatenotifier();
+    if (updatenotifier) updatenotifier(mailbox);
 }
 
 
diff -ur cyrus-imapd-2.1.16-DIST/imap/mailbox.c cyrus-imapd-2.1.16/imap/mailbox.c
--- cyrus-imapd-2.1.16-DIST/imap/mailbox.c	2003-11-04 21:43:00.000000000 +0000
+++ cyrus-imapd-2.1.16/imap/mailbox.c	2005-04-04 10:28:46.831392889 +0100
@@ -143,6 +143,14 @@
 }
 
 /*
+ * Get the updatenotifier function
+ */
+mailbox_notifyproc_t *mailbox_get_updatenotifier(void)
+{
+    return updatenotifier;
+}
+
+/*
  * Create connection to acappush
  */
 int mailbox_initialize(void)
diff -ur cyrus-imapd-2.1.16-DIST/imap/mailbox.h cyrus-imapd-2.1.16/imap/mailbox.h
--- cyrus-imapd-2.1.16-DIST/imap/mailbox.h	2003-03-31 21:15:05.000000000 +0100
+++ cyrus-imapd-2.1.16/imap/mailbox.h	2005-04-04 10:24:00.889693737 +0100
@@ -218,6 +218,8 @@
 
 extern void mailbox_set_updatenotifier(mailbox_notifyproc_t *notifyproc);
 
+extern mailbox_notifyproc_t *mailbox_get_updatenotifier(void);
+
 extern int mailbox_initialize(void);
 
 extern char *mailbox_message_fname(struct mailbox *mailbox,