1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
package cache
import (
"errors"
"io"
"os"
"sync"
"time"
"github.com/vmihailenco/msgpack"
)
type DB[K any, V any] struct {
file io.WriteSeeker
Store Store
snapshotTicker *pauseTimer
cleanupTicker *pauseTimer
stop chan struct{}
wg sync.WaitGroup
}
func OpenFile[K any, V any](filename string) (*DB[K, V], error) {
ret := OpenMem[K, V]()
file, err := os.OpenFile(filename, os.O_RDWR, 0)
if errors.Is(err, os.ErrNotExist) {
file, err := os.Create(filename)
if err != nil {
return nil, err
}
ret.file = file
ret.Flush()
} else if err == nil {
ret.Store.LoadSnapshot(file)
ret.file = file
} else {
return nil, err
}
return ret, nil
}
func OpenMem[K any, V any]() *DB[K, V] {
ret := &DB[K, V]{
snapshotTicker: newPauseTimer(0),
}
ret.snapshotTicker.Stop()
ret.Clear()
ret.Store.strategy.evict = &ret.Store.evict
ret.SetStratergy(StrategyNone)
return ret
}
func (d *DB[K, V]) Start() {
d.stop = make(chan struct{})
d.wg.Add(1)
go d.backgroundWorker()
}
func (d *DB[K, V]) SetStratergy(e EvictionPolicyType) error {
return d.Store.strategy.SetPolicy(e)
}
func (d *DB[K, V]) SetMaxCost(e EvictionPolicyType) {
d.Store.maxCost = d.Store.maxCost
}
func (d *DB[K, V]) SetSnapshotTime(t time.Duration) {
d.snapshotTicker.Reset(t)
}
func (d *DB[K, V]) backgroundWorker() {
defer d.wg.Done()
d.snapshotTicker.Resume()
defer d.snapshotTicker.Stop()
for {
select {
case <-d.stop:
return
case <-d.snapshotTicker.C:
d.Flush()
case <-d.snapshotTicker.C:
d.Flush()
}
}
}
func (d *DB[K, V]) Close() {
close(d.stop)
d.wg.Wait()
d.Flush()
d.Clear()
if d.file != nil {
closer, ok := d.file.(io.Closer)
if ok {
closer.Close()
}
}
}
func (d *DB[K, V]) Flush() error {
if d.file != nil {
return d.Store.Snapshot(d.file)
}
return nil
}
func (d *DB[K, V]) Clear() {
d.Store.Clear()
}
var ErrKeyNotFound = errors.New("key not found")
func (h *DB[K, V]) Get(key K) (V, time.Duration, error) {
keyData, err := msgpack.Marshal(key)
if err != nil {
return zero[V](), 0, err
}
v, ttl, ok := h.Store.Get(keyData)
if !ok {
return zero[V](), 0, ErrKeyNotFound
}
var ret V
if err = msgpack.Unmarshal(v, &ret); err != nil {
return zero[V](), 0, err
}
return ret, ttl, err
}
func (h *DB[K, V]) Set(key K, value V, ttl time.Duration) error {
keyData, err := msgpack.Marshal(key)
if err != nil {
return err
}
valueData, err := msgpack.Marshal(value)
if err != nil {
return err
}
h.Store.Set(keyData, valueData, ttl)
return nil
}
func (h *DB[K, V]) Delete(key K) error {
keyData, err := msgpack.Marshal(key)
if err != nil {
return err
}
ok := h.Store.Delete(keyData)
if !ok {
return ErrKeyNotFound
}
return nil
}
|
