1package volatile
 2
 3import (
 4	"fmt"
 5	"time"
 6)
 7
 8type Element[V any] struct {
 9	value     *V
10	Timestamp time.Time
11}
12
13type Volatile[K comparable, V any] struct {
14	data       map[K]Element[V]
15	timeToLive time.Duration
16}
17
18func (v *Volatile[K, V]) clean() (count int) {
19	now := time.Now()
20
21	for key, value := range v.data {
22		if now.Sub(value.Timestamp) > v.timeToLive {
23			delete(v.data, key)
24			count += 1
25		}
26	}
27	return
28}
29
30func (v *Volatile[K, V]) cleanupRoutine(interval time.Duration) {
31	ticker := time.NewTicker(interval)
32	defer ticker.Stop()
33
34	for range ticker.C {
35		v.clean()
36	}
37}
38
39func NewVolatile[K comparable, V any](timeToLive time.Duration, cleanupInterval time.Duration) *Volatile[K, V] {
40	v := &Volatile[K, V]{
41		timeToLive: timeToLive,
42	}
43	v.Clear()
44	go v.cleanupRoutine(cleanupInterval)
45	return v
46}
47
48func (v *Volatile[K, V]) Has(key K) (ok bool) {
49	v.clean()
50	_, ok = v.data[key]
51	return
52}
53
54func (v *Volatile[K, V]) Get(key K) (*V, error) {
55	v.clean()
56	element, ok := v.data[key]
57
58	if !ok {
59		return nil, fmt.Errorf("not found")
60	}
61
62	return element.value, nil
63}
64
65func (v *Volatile[K, V]) Remove(key K) (*V, error) {
66	v.clean()
67	value, ok := v.data[key]
68
69	if !ok {
70		return nil, fmt.Errorf("not found")
71	}
72
73	delete(v.data, key)
74	return value.value, nil
75}
76
77func (v *Volatile[K, V]) Length() int {
78	v.clean()
79	return len(v.data)
80}
81
82func (v *Volatile[K, V]) Clear() {
83	v.data = make(map[K]Element[V])
84}
85
86func (v *Volatile[K, V]) Set(key K, value *V) {
87	v.data[key] = Element[V]{value: value, Timestamp: time.Now()}
88	v.clean()
89}