aerc/worker/imap/seqmap.go

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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 {
m := make(map[uint32]uint32)
for s, u := range s.m {
if s > seqnum {
// All sequence numbers greater than the removed one must be decremented by one
// https://datatracker.ietf.org/doc/html/rfc3501#section-7.4.1
m[s-1] = u
} else if s < seqnum {
m[s] = u
}
}
s.m = m
}
s.lock.Unlock()
return uid, found
}
func (s *SeqMap) Clear() {
s.lock.Lock()
s.m = make(map[uint32]uint32)
s.lock.Unlock()
}