imapmemserver: add support for the recent flag

imapserver/imapmemserver/mailbox.go

@@ -76,6 +76,10 @@ func (mbox *Mailbox) statusDataLocked(options *imap.StatusOptions) *imap.StatusD
 		num := uint32(len(mbox.l))
 		data.NumMessages = &num
 	}
+	if options.NumRecent {
+		num := mbox.countByFlagLocked("\\Recent")
+		data.NumRecent = &num
+	}
 	if options.UIDNext {
 		data.UIDNext = mbox.uidNext
 	}
@@ -94,10 +98,6 @@ func (mbox *Mailbox) statusDataLocked(options *imap.StatusOptions) *imap.StatusD
 		size := mbox.sizeLocked()
 		data.Size = &size
 	}
-	if options.NumRecent {
-		num := uint32(0)
-		data.NumRecent = &num
-	}
 	return &data
 }
 
@@ -146,6 +146,7 @@ func (mbox *Mailbox) appendBytes(buf []byte, options *imap.AppendOptions) *imap.
 		msg.t = options.Time
 	}
 
+	msg.flags[canonicalFlag("\\Recent")] = struct{}{}
 	for _, flag := range options.Flags {
 		msg.flags[canonicalFlag(flag)] = struct{}{}
 	}
@@ -188,12 +189,14 @@ func (mbox *Mailbox) selectDataLocked() *imap.SelectData {
 	// TODO: skip if IMAP4rev1 is disabled by the server, or IMAP4rev2 is
 	// enabled by the client
 	firstUnseenSeqNum := mbox.firstUnseenSeqNumLocked()
+	numRecent := mbox.countByFlagLocked("\\Recent")
 
 	return &imap.SelectData{
 		Flags:             flags,
 		PermanentFlags:    permanentFlags,
 		NumMessages:       uint32(len(mbox.l)),
 		FirstUnseenSeqNum: firstUnseenSeqNum,
+		NumRecent:         numRecent,
 		UIDNext:           mbox.uidNext,
 		UIDValidity:       mbox.uidValidity,
 	}
@@ -283,10 +286,12 @@ func (mbox *Mailbox) expungeLocked(expunged map[*message]struct{}) (seqNums []ui
 // NewView creates a new view into this mailbox.
 //
 // Callers must call MailboxView.Close once they are done with the mailbox view.
-func (mbox *Mailbox) NewView() *MailboxView {
+func (mbox *Mailbox) NewView(options *imap.SelectOptions) *MailboxView {
 	return &MailboxView{
-		Mailbox: mbox,
-		tracker: mbox.tracker.NewSession(),
+		Mailbox:  mbox,
+		tracker:  mbox.tracker.NewSession(),
+		readOnly: options.ReadOnly,
+		recent:   make(map[imap.UID]struct{}),
 	}
 }
 
@@ -300,8 +305,11 @@ func (mbox *Mailbox) NewView() *MailboxView {
 // selected state.
 type MailboxView struct {
 	*Mailbox
-	tracker   *imapserver.SessionTracker
-	searchRes imap.UIDSet
+	readOnly      bool // immutable
+	tracker       *imapserver.SessionTracker
+	searchRes     imap.UIDSet
+	recent        map[imap.UID]struct{}
+	prevNumRecent uint32
 }
 
 // Close releases the resources allocated for the mailbox view.
@@ -330,7 +338,8 @@ func (mbox *MailboxView) Fetch(w *imapserver.FetchWriter, numSet imap.NumSet, op
 		}
 
 		respWriter := w.CreateMessage(mbox.tracker.EncodeSeqNum(seqNum))
-		err = msg.fetch(respWriter, options)
+		_, isRecent := mbox.recent[msg.uid]
+		err = msg.fetch(respWriter, options, isRecent)
 	})
 	return err
 }
@@ -349,7 +358,8 @@ func (mbox *MailboxView) Search(numKind imapserver.NumKind, criteria *imap.Searc
 	for i, msg := range mbox.l {
 		seqNum := mbox.tracker.EncodeSeqNum(uint32(i) + 1)
 
-		if !msg.search(seqNum, criteria) {
+		_, isRecent := mbox.recent[msg.uid]
+		if !msg.search(seqNum, criteria, isRecent) {
 			continue
 		}
 
@@ -429,7 +439,19 @@ func (mbox *MailboxView) Store(w *imapserver.FetchWriter, numSet imap.NumSet, fl
 }
 
 func (mbox *MailboxView) Poll(w *imapserver.UpdateWriter, allowExpunge bool) error {
-	return mbox.tracker.Poll(w, allowExpunge)
+	if err := mbox.tracker.Poll(w, allowExpunge); err != nil {
+		return err
+	}
+	mbox.mutex.Lock()
+	mbox.pollRecentLocked()
+	numRecent := uint32(len(mbox.recent))
+	sendNumRecent := numRecent != mbox.prevNumRecent
+	mbox.prevNumRecent = numRecent
+	mbox.mutex.Unlock()
+	if sendNumRecent {
+		w.WriteNumRecent(numRecent)
+	}
+	return nil
 }
 
 func (mbox *MailboxView) Idle(w *imapserver.UpdateWriter, stop <-chan struct{}) error {
@@ -509,3 +531,15 @@ func staticNumRange(start, stop *uint32, max uint32) {
 		*start, *stop = *stop, *start
 	}
 }
+
+func (mbox *MailboxView) pollRecentLocked() {
+	if mbox.readOnly {
+		return
+	}
+	for _, msg := range mbox.l {
+		if _, ok := msg.flags[canonicalFlag("\\Recent")]; ok {
+			mbox.recent[msg.uid] = struct{}{}
+			delete(msg.flags, canonicalFlag("\\Recent"))
+		}
+	}
+}

imapserver/imapmemserver/message.go

@@ -25,11 +25,15 @@ type message struct {
 	flags map[imap.Flag]struct{}
 }
 
-func (msg *message) fetch(w *imapserver.FetchResponseWriter, options *imap.FetchOptions) error {
+func (msg *message) fetch(w *imapserver.FetchResponseWriter, options *imap.FetchOptions, isRecent bool) error {
 	w.WriteUID(msg.uid)
 
 	if options.Flags {
-		w.WriteFlags(msg.flagList())
+		flags := msg.flagList()
+		if isRecent {
+			flags = append(flags, "\\Recent")
+		}
+		w.WriteFlags(flags)
 	}
 	if options.InternalDate {
 		w.WriteInternalDate(msg.t)
@@ -121,7 +125,7 @@ func (msg *message) reader() *gomessage.Entity {
 	return r
 }
 
-func (msg *message) search(seqNum uint32, criteria *imap.SearchCriteria) bool {
+func (msg *message) search(seqNum uint32, criteria *imap.SearchCriteria, isRecent bool) bool {
 	for _, seqSet := range criteria.SeqNum {
 		if seqNum == 0 || !seqSet.Contains(seqNum) {
 			return false
@@ -136,13 +140,20 @@ func (msg *message) search(seqNum uint32, criteria *imap.SearchCriteria) bool {
 		return false
 	}
 
+	hasFlag := func(flag imap.Flag) bool {
+		if isRecent && canonicalFlag(flag) == canonicalFlag("\\Recent") {
+			return true
+		}
+		_, ok := msg.flags[canonicalFlag(flag)]
+		return ok
+	}
 	for _, flag := range criteria.Flag {
-		if _, ok := msg.flags[canonicalFlag(flag)]; !ok {
+		if !hasFlag(flag) {
 			return false
 		}
 	}
 	for _, flag := range criteria.NotFlag {
-		if _, ok := msg.flags[canonicalFlag(flag)]; ok {
+		if hasFlag(flag) {
 			return false
 		}
 	}
@@ -183,12 +194,12 @@ func (msg *message) search(seqNum uint32, criteria *imap.SearchCriteria) bool {
 	}
 
 	for _, not := range criteria.Not {
-		if msg.search(seqNum, &not) {
+		if msg.search(seqNum, &not, isRecent) {
 			return false
 		}
 	}
 	for _, or := range criteria.Or {
-		if !msg.search(seqNum, &or[0]) && !msg.search(seqNum, &or[1]) {
+		if !msg.search(seqNum, &or[0], isRecent) && !msg.search(seqNum, &or[1], isRecent) {
 			return false
 		}
 	}

imapserver/imapmemserver/session.go

@@ -40,8 +40,13 @@ func (sess *UserSession) Select(name string, options *imap.SelectOptions) (*imap
 	}
 	mbox.mutex.Lock()
 	defer mbox.mutex.Unlock()
-	sess.mailbox = mbox.NewView()
-	return mbox.selectDataLocked(), nil
+	sess.mailbox = mbox.NewView(options)
+	data := mbox.selectDataLocked()
+	if !options.ReadOnly && data.NumRecent > 0 {
+		sess.mailbox.pollRecentLocked()
+		sess.mailbox.prevNumRecent = data.NumRecent
+	}
+	return data, nil
 }
 
 func (sess *UserSession) Unselect() error {
@@ -138,3 +143,20 @@ func (sess *UserSession) Idle(w *imapserver.UpdateWriter, stop <-chan struct{})
 	}
 	return sess.mailbox.Idle(w, stop)
 }
+
+func (sess *UserSession) Status(name string, options *imap.StatusOptions) (*imap.StatusData, error) {
+	data, err := sess.user.Status(name, options)
+	if err != nil {
+		return nil, err
+	}
+
+	if mbox := sess.mailbox; mbox != nil && data.NumRecent != nil {
+		mbox.mutex.Lock()
+		if mbox.name == name {
+			*data.NumRecent += uint32(len(mbox.recent))
+		}
+		mbox.mutex.Unlock()
+	}
+
+	return data, nil
+}