Zijing Zhang
f56ac4eabc
* feat: garbage collection feature A new `GC()` method has been added to the `Cache` struct, which performs garbage collection by deleting expired entries from the cache.
83 lines
1.5 KiB
Go
83 lines
1.5 KiB
Go
package simple_cache
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import (
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"sync"
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"sync/atomic"
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"time"
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)
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type Cache struct {
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data sync.Map
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// when the number of entries reaches gcThold, GC will be triggered
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gcThold int
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len atomic.Int32
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}
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func New() *Cache {
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return &Cache{
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gcThold: 1000,
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len: atomic.Int32{},
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}
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}
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func NewWithGCThold(gcThold int) *Cache {
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return &Cache{
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gcThold: gcThold,
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len: atomic.Int32{},
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}
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}
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type cacheEntry struct {
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value interface{}
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expiration time.Time
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}
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func (c *Cache) Set(key string, value interface{}, expirationParam ...time.Duration) {
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defer c.GC(false)
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var expirationTime time.Time
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if len(expirationParam) > 0 && expirationParam[0] > 0 {
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expirationTime = time.Now().Add(expirationParam[0])
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}
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entry := cacheEntry{
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value: value,
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expiration: expirationTime,
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}
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c.data.Store(key, entry)
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c.len.Add(1)
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}
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func (c *Cache) Get(key string) (interface{}, bool) {
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defer c.GC(false)
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if val, found := c.data.Load(key); found {
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entry := val.(cacheEntry)
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if !isExpired(entry) {
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return entry.value, true
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}
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c.data.Delete(key)
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}
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return nil, false
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}
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func (c *Cache) Delete(key string) {
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c.data.Delete(key)
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c.len.Add(-1)
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}
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func (c* Cache) GC(force bool) {
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if int(c.len.Load()) < c.gcThold && !force {
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return
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}
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c.data.Range(func(key, value interface{}) bool {
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entry := value.(cacheEntry)
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if !isExpired(entry) {
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return true
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}
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c.Delete(key.(string))
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return true
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})
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}
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func isExpired(entry cacheEntry) bool {
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return !entry.expiration.IsZero() && entry.expiration.Before(time.Now())
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}
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