92 lines
1.5 KiB
Go
92 lines
1.5 KiB
Go
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package cache
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import (
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"runtime"
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"sync"
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"time"
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)
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// Cache store element with a expired time
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type Cache struct {
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*cache
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}
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type cache struct {
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mapping sync.Map
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janitor *janitor
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}
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type element struct {
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Expired time.Time
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Payload interface{}
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}
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// Put element in Cache with its ttl
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func (c *cache) Put(key interface{}, payload interface{}, ttl time.Duration) {
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c.mapping.Store(key, &element{
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Payload: payload,
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Expired: time.Now().Add(ttl),
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})
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}
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// Get element in Cache, and drop when it expired
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func (c *cache) Get(key interface{}) interface{} {
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item, exist := c.mapping.Load(key)
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if !exist {
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return nil
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}
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elm := item.(*element)
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// expired
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if time.Since(elm.Expired) > 0 {
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c.mapping.Delete(key)
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return nil
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}
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return elm.Payload
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}
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func (c *cache) cleanup() {
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c.mapping.Range(func(k, v interface{}) bool {
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key := k.(string)
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elm := v.(*element)
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if time.Since(elm.Expired) > 0 {
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c.mapping.Delete(key)
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}
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return true
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})
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}
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type janitor struct {
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interval time.Duration
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stop chan struct{}
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}
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func (j *janitor) process(c *cache) {
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ticker := time.NewTicker(j.interval)
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for {
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select {
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case <-ticker.C:
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c.cleanup()
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case <-j.stop:
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ticker.Stop()
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return
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}
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}
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}
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func stopJanitor(c *Cache) {
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c.janitor.stop <- struct{}{}
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}
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// New return *Cache
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func New(interval time.Duration) *Cache {
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j := &janitor{
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interval: interval,
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stop: make(chan struct{}),
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}
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c := &cache{janitor: j}
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go j.process(c)
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C := &Cache{c}
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runtime.SetFinalizer(C, stopJanitor)
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return C
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}
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