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package slack
import (
"sync"
"time"
"github.com/golang/groupcache/lru"
)
type ttlCache[K comparable, V any] struct {
*lru.Cache
ttl time.Duration
// We use a mutex to protect the cache from concurrent access
// as this is not handled by the lru package.
//
// See https://github.com/golang/groupcache/issues/87#issuecomment-338494548
mx sync.Mutex
}
func newTTLCache[K comparable, V any](maxEntries int, ttl time.Duration) *ttlCache[K, V] {
return &ttlCache[K, V]{
ttl: ttl,
Cache: lru.New(maxEntries),
}
}
type cacheItem[V any] struct {
expires time.Time
value V
}
func (c *ttlCache[K, V]) Add(key lru.Key, value V) {
c.mx.Lock()
defer c.mx.Unlock()
c.Cache.Add(key, cacheItem[V]{
value: value,
expires: time.Now().Add(c.ttl),
})
}
func (c *ttlCache[K, V]) Get(key K) (val V, ok bool) {
c.mx.Lock()
defer c.mx.Unlock()
item, ok := c.Cache.Get(key)
if !ok {
return val, false
}
cItem := item.(cacheItem[V])
if time.Until(cItem.expires) > 0 {
return cItem.value, true
}
return val, false
}
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