1 files changed, 48 insertions, 0 deletions
diff --git a/worker/imap/seqmap.go b/worker/imap/seqmap.go
new file mode 100644
index 00000000..2752cc87
--- /dev/null
+++ b/worker/imap/seqmap.go
@@ -0,0 +1,48 @@
+package imap
+
+import "sync"
+
+type SeqMap struct {
+	lock sync.Mutex
+	// map of IMAP sequence numbers to message UIDs
+	m map[uint32]uint32
+}
+
+func (s *SeqMap) Size() int {
+	s.lock.Lock()
+	size := len(s.m)
+	s.lock.Unlock()
+	return size
+}
+
+func (s *SeqMap) Get(seqnum uint32) (uint32, bool) {
+	s.lock.Lock()
+	uid, found := s.m[seqnum]
+	s.lock.Unlock()
+	return uid, found
+}
+
+func (s *SeqMap) Put(seqnum, uid uint32) {
+	s.lock.Lock()
+	if s.m == nil {
+		s.m = make(map[uint32]uint32)
+	}
+	s.m[seqnum] = uid
+	s.lock.Unlock()
+}
+
+func (s *SeqMap) Pop(seqnum uint32) (uint32, bool) {
+	s.lock.Lock()
+	uid, found := s.m[seqnum]
+	if found {
+		delete(s.m, seqnum)
+	}
+	s.lock.Unlock()
+	return uid, found
+}
+
+func (s *SeqMap) Clear() {
+	s.lock.Lock()
+	s.m = make(map[uint32]uint32)
+	s.lock.Unlock()
+}