aerc/worker/imap/seqmap.go

77 lines
1.5 KiB
Go

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 = 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) {
if int(seqnum) > s.Size() || seqnum < 1 {
return 0, false
}
s.lock.Lock()
uid := s.m[seqnum-1]
s.m = append(s.m[:seqnum-1], s.m[seqnum:]...)
s.lock.Unlock()
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]
})
}