init: pristine aerc 0.20.0 source

worker/imap/seqmap.go

@@ -0,0 +1,77 @@
+package imap
+
+import (
+	"sort"
+	"sync"
+)
+
+type SeqMap struct {
+	lock sync.Mutex
+	// map of IMAP sequence numbers to message UIDs
+	m []uint32
+}
+
+// Initialize sets the initial seqmap of the mailbox
+func (s *SeqMap) Initialize(uids []uint32) {
+	s.lock.Lock()
+	s.m = make([]uint32, len(uids))
+	copy(s.m, uids)
+	s.sort()
+	s.lock.Unlock()
+}
+
+func (s *SeqMap) Size() int {
+	s.lock.Lock()
+	size := len(s.m)
+	s.lock.Unlock()
+	return size
+}
+
+// Get returns the UID of the given seqnum
+func (s *SeqMap) Get(seqnum uint32) (uint32, bool) {
+	if int(seqnum) > s.Size() || seqnum < 1 {
+		return 0, false
+	}
+	s.lock.Lock()
+	uid := s.m[seqnum-1]
+	s.lock.Unlock()
+	return uid, true
+}
+
+// Put adds a UID to the slice. Put should only be used to add new messages
+// into the slice
+func (s *SeqMap) Put(uid uint32) {
+	s.lock.Lock()
+	for _, n := range s.m {
+		if n == uid {
+			// We already have this UID, don't insert it.
+			s.lock.Unlock()
+			return
+		}
+	}
+	s.m = append(s.m, uid)
+	s.sort()
+	s.lock.Unlock()
+}
+
+// Pop removes seqnum from the SeqMap. seqnum must be a valid seqnum, ie
+// [1:size of mailbox]
+func (s *SeqMap) Pop(seqnum uint32) (uint32, bool) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	if int(seqnum) > len(s.m) || seqnum < 1 {
+		return 0, false
+	}
+	uid := s.m[seqnum-1]
+	s.m = append(s.m[:seqnum-1], s.m[seqnum:]...)
+	return uid, true
+}
+
+// sort sorts the slice in ascending UID order. See:
+// https://datatracker.ietf.org/doc/html/rfc3501#section-2.3.1.2
+func (s *SeqMap) sort() {
+	// Always be sure the SeqMap is sorted
+	sort.Slice(s.m, func(i, j int) bool {
+		return s.m[i] < s.m[j]
+	})
+}