# Small patch to Cyrus IMAP 2.2.12 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.
#
# This patch is a 2.2.12 port from the patch found here:
# http://www-uxsup.csx.cam.ac.uk/~dpc22/cyrus/patches/2.1.16/seenstate.patch
#
diff -Naur cyrus-imapd-2.2.12.orig/imap/imapd.c cyrus-imapd-2.2.12/imap/imapd.c
--- cyrus-imapd-2.2.12.orig/imap/imapd.c	2005-02-14 07:39:55.000000000 +0100
+++ cyrus-imapd-2.2.12/imap/imapd.c	2006-01-04 07:41:45.000000000 +0100
@@ -3095,6 +3095,10 @@
     snprintf(mytime, sizeof(mytime), "%2.3f", 
 	     (clock() - start) / (double) CLOCKS_PER_SEC);
 
+    /* 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 (r) {
 	prot_printf(imapd_out, "%s NO %s (%s sec)\r\n", tag,
 		    error_message(r), mytime);
@@ -3219,7 +3223,8 @@
 
     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,
@@ -3352,7 +3357,9 @@
 		    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 -Naur cyrus-imapd-2.2.12.orig/imap/imapd.h cyrus-imapd-2.2.12/imap/imapd.h
--- cyrus-imapd-2.2.12.orig/imap/imapd.h	2004-06-22 23:36:18.000000000 +0200
+++ cyrus-imapd-2.2.12/imap/imapd.h	2006-01-04 07:41:45.000000000 +0100
@@ -232,6 +232,8 @@
 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 -Naur cyrus-imapd-2.2.12.orig/imap/index.c cyrus-imapd-2.2.12/imap/index.c
--- cyrus-imapd-2.2.12.orig/imap/index.c	2005-02-14 17:42:08.000000000 +0100
+++ cyrus-imapd-2.2.12/imap/index.c	2006-01-04 08:08:51.000000000 +0100
@@ -425,6 +425,53 @@
     }
 }
 
+/* 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)
+{
+    struct stat sbuf;
+    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
  *
@@ -458,6 +505,7 @@
     char *saveseenuids, *save;
     int savealloced;
     unsigned start, newallseen, inrange, usecomma;
+    mailbox_notifyproc_t *updatenotifier;
 
     if (!keepingseen || !seendb) return;
     if (imapd_exists == 0) {
@@ -731,6 +779,9 @@
 
     free(newseenuids);
     seenuids = saveseenuids;
+
+    updatenotifier = mailbox_get_updatenotifier();
+    if (updatenotifier) updatenotifier(mailbox);
 }
 
 
diff -Naur cyrus-imapd-2.2.12.orig/imap/mailbox.c cyrus-imapd-2.2.12/imap/mailbox.c
--- cyrus-imapd-2.2.12.orig/imap/mailbox.c	2005-02-14 07:39:57.000000000 +0100
+++ cyrus-imapd-2.2.12/imap/mailbox.c	2006-01-04 07:41:45.000000000 +0100
@@ -230,6 +230,14 @@
 }
 
 /*
+ * Get the updatenotifier function
+ */
+mailbox_notifyproc_t *mailbox_get_updatenotifier(void)
+{
+    return updatenotifier;
+}
+
+/*
  * Create connection to acappush (obsolete)
  */
 int mailbox_initialize(void)
diff -Naur cyrus-imapd-2.2.12.orig/imap/mailbox.h cyrus-imapd-2.2.12/imap/mailbox.h
--- cyrus-imapd-2.2.12.orig/imap/mailbox.h	2004-01-22 22:17:09.000000000 +0100
+++ cyrus-imapd-2.2.12/imap/mailbox.h	2006-01-04 07:41:45.000000000 +0100
@@ -224,6 +224,8 @@
 
 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,