imapserver: add SelectData.FirstUnseenSeqNum

Author: emersion

imapserver/select.go

@@ -45,6 +45,11 @@ func (c *Conn) handleSelect(tag string, dec *imapwire.Decoder, readOnly bool) er
 		if err := c.writeObsoleteRecent(data.NumRecent); err != nil {
 			return err
 		}
+		if data.FirstUnseenSeqNum != 0 {
+			if err := c.writeObsoleteUnseen(data.FirstUnseenSeqNum); err != nil {
+				return err
+			}
+		}
 	}
 	if err := c.writeUIDValidity(data.UIDValidity); err != nil {
 		return err
@@ -121,6 +126,15 @@ func (c *Conn) writeObsoleteRecent(n uint32) error {
 	return enc.Atom("*").SP().Number(n).SP().Atom("RECENT").CRLF()
 }
 
+func (c *Conn) writeObsoleteUnseen(n uint32) error {
+	enc := newResponseEncoder(c)
+	defer enc.end()
+	enc.Atom("*").SP().Atom("OK").SP()
+	enc.Special('[').Atom("UNSEEN").SP().Number(n).Special(']')
+	enc.SP().Text("First unseen message")
+	return enc.CRLF()
+}
+
 func (c *Conn) writeUIDValidity(uidValidity uint32) error {
 	enc := newResponseEncoder(c)
 	defer enc.end()

select.go

@@ -16,7 +16,10 @@ type SelectData struct {
 	PermanentFlags []Flag
 	// Number of messages in this mailbox (aka. "EXISTS")
 	NumMessages uint32
-	// Number of recent messages in this mailbox ("RECENT") (Obsolete, IMAP4rev1 only).
+	// Sequence number of the first unseen message. Obsolete, IMAP4rev1 only.
+	// Server-only, not supported in imapclient.
+	FirstUnseenSeqNum uint32
+	// Number of recent messages in this mailbox. Obsolete, IMAP4rev1 only.
 	// Server-only, not supported in imapclient.
 	NumRecent   uint32
 	UIDNext     UID