Method Push

internal/data/list.go:164–204

(key string, r *core.Record, isLeft bool)

}

func (l *List) Push(key string, r *core.Record, isLeft bool) error {
	// key is seq + user_key
	userKey, curSeq := utils.DecodeListKey([]byte(key))
	userKeyStr := string(userKey)
	if l.IsExpire(userKeyStr) {
		return ErrListNotFound
	}

	list, ok := l.Items[userKeyStr]
	if !ok {
		l.Items[userKeyStr] = l.CreateListStructure()
		list = l.Items[userKeyStr]
	}

	// Initialize seq if not exists
	if _, ok := l.Seq[userKeyStr]; !ok {
		l.Seq[userKeyStr] = &HeadTailSeq{Head: InitialListSeq, Tail: InitialListSeq + 1}
	}

	list.InsertRecord(utils.ConvertUint64ToBigEndianBytes(curSeq), r)

	// Update seq boundaries to track the next insertion positions
	// This is important for recovery scenarios where we rebuild the index
	// Head and Tail should always represent the next available positions for insertion
	seq := l.Seq[userKeyStr]
	if isLeft {
		// LPush: Head should be the next available position on the left
		// If current seq is the actual head, set Head to current seq - 1
		if curSeq <= seq.Head {
			seq.Head = curSeq - 1
		}
	} else {
		// RPush: Tail should be the next available position on the right
		// If current seq is at or beyond current tail, update Tail accordingly
		if curSeq >= seq.Tail {
			seq.Tail = curSeq + 1
		}
	}

	return nil
}

func (l *List) LPop(key string) (*core.Record, error) {
	if l.IsExpire(key) {