move timedValue -> cachevalue package (#19114)

cmd/utils.go

@@ -926,102 +926,6 @@ func iamPolicyClaimNameSA() string {
 	return "sa-policy"
 }
 
-// timedValue contains a synchronized value that is considered valid
-// for a specific amount of time.
-// An Update function must be set to provide an updated value when needed.
-type timedValue[I any] struct {
-	// Update must return an updated value.
-	// If an error is returned the cached value is not set.
-	// Only one caller will call this function at any time, others will be blocking.
-	// The returned value can no longer be modified once returned.
-	// Should be set before calling Get().
-	Update func() (item I, err error)
-
-	// TTL for a cached value.
-	// If not set 1 second TTL is assumed.
-	// Should be set before calling Get().
-	TTL time.Duration
-
-	// When set to true, return the last cached value
-	// even if updating the value errors out
-	Relax bool
-
-	// Once can be used to initialize values for lazy initialization.
-	// Should be set before calling Get().
-	Once sync.Once
-
-	// Managed values.
-	value      I
-	valueSet   bool
-	lastUpdate time.Time
-	mu         sync.RWMutex
-}
-
-// newTimedValue
-func newTimedValue[I any]() *timedValue[I] {
-	return &timedValue[I]{}
-}
-
-// Get will return a cached value or fetch a new one.
-// If the Update function returns an error the value is forwarded as is and not cached.
-func (t *timedValue[I]) Get() (item I, err error) {
-	item, ok := t.get(t.ttl())
-	if ok {
-		return item, nil
-	}
-
-	item, err = t.Update()
-	if err != nil {
-		if t.Relax {
-			// if update fails, return current
-			// cached value along with error.
-			//
-			// Let the caller decide if they want
-			// to use the returned value based
-			// on error.
-			item, ok = t.get(0)
-			if ok {
-				return item, err
-			}
-		}
-		return item, err
-	}
-
-	t.update(item)
-	return item, nil
-}
-
-func (t *timedValue[_]) ttl() time.Duration {
-	ttl := t.TTL
-	if ttl <= 0 {
-		ttl = time.Second
-	}
-	return ttl
-}
-
-func (t *timedValue[I]) get(ttl time.Duration) (item I, ok bool) {
-	t.mu.RLock()
-	defer t.mu.RUnlock()
-	if t.valueSet {
-		item = t.value
-		if ttl <= 0 {
-			return item, true
-		}
-		if time.Since(t.lastUpdate) < ttl {
-			return item, true
-		}
-	}
-	return item, false
-}
-
-func (t *timedValue[I]) update(item I) {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-	t.value = item
-	t.valueSet = true
-	t.lastUpdate = time.Now()
-}
-
 // On MinIO a directory object is stored as a regular object with "__XLDIR__" suffix.
 // For ex. "prefix/" is stored as "prefix__XLDIR__"
 func encodeDirObject(object string) string {