cache

type Cache interface {
	// GetIfPresent returns value associated with Key or (nil, false)
	// if there is no cached value for Key.
	GetIfPresent(Key) (Value, bool)

	// Put associates value with Key. If a value is already associated
	// with Key, the old one will be replaced with Value.
	Put(Key, Value)

	// Invalidate discards cached value of the given Key.
	Invalidate(Key)

	// InvalidateAll discards all entries.
	InvalidateAll()

	// Stats copies cache statistics to given Stats pointer.
	Stats(*Stats)

	// Close implements io.Closer for cleaning up all resources.
	// Users must ensure the cache is not being used before closing or
	// after closed.
	Close() error
}

type Func func(Key, Value)

type Hash interface {
	Sum64() uint64
}

type Key interface{}

type LoaderFunc func(Key) (Value, error)

type LoadingCache interface {
	Cache

	// Get returns value associated with Key or call underlying LoaderFunc
	// to load value if it is not present.
	Get(Key) (Value, error)

	// Refresh loads new value for Key. If the Key already existed, the previous value
	// will continue to be returned by Get while the new value is loading.
	// If Key does not exist, this function will block until the value is loaded.
	Refresh(Key)
}

type Option func(c *localCache)

type Reloader interface {
	// Reload should reload the value asynchronously.
	// Application must call setFunc to set new value or error.
	Reload(key Key, oldValue Value, setFunc func(Value, error))
	// Close shuts down all running tasks. Currently, the error returned is not being used.
	Close() error
}

type Stats struct {
	HitCount         uint64
	MissCount        uint64
	LoadSuccessCount uint64
	LoadErrorCount   uint64
	TotalLoadTime    time.Duration
	EvictionCount    uint64
}

type StatsCounter interface {
	// RecordHits records cache hits.
	RecordHits(count uint64)

	// RecordMisses records cache misses.
	RecordMisses(count uint64)

	// RecordLoadSuccess records successful load of a new entry.
	RecordLoadSuccess(loadTime time.Duration)

	// RecordLoadError records failed load of a new entry.
	RecordLoadError(loadTime time.Duration)

	// RecordEviction records eviction of an entry from the cache.
	RecordEviction()

	// Snapshot writes snapshot of this counter values to the given Stats pointer.
	Snapshot(*Stats)
}

type Value interface{}