Documentation
¶
Index ¶
- type EvictCallback
- type LRU
- func (c *LRU[K, V]) Add(key K, value V) (evicted bool)
- func (c *LRU[K, V]) Contains(key K) (ok bool)
- func (c *LRU[K, V]) Get(key K) (value V, ok bool)
- func (c *LRU[K, V]) GetOldest() (key K, value V, ok bool)
- func (c *LRU[K, V]) Keys() []K
- func (c *LRU[K, V]) Len() int
- func (c *LRU[K, V]) Peek(key K) (value V, ok bool)
- func (c *LRU[K, V]) Purge()
- func (c *LRU[K, V]) Remove(key K) bool
- func (c *LRU[K, V]) RemoveOldest() (key K, value V, ok bool)
- func (c *LRU[K, V]) Resize(size int) (evicted int)
- func (c *LRU[K, V]) Values() []V
Examples ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type EvictCallback ¶
type EvictCallback[K comparable, V any] func(key K, value V)
EvictCallback is used to get a callback when a cache entry is evicted
type LRU ¶
type LRU[K comparable, V any] struct { // contains filtered or unexported fields }
LRU implements a thread-safe LRU with expirable entries.
Example ¶
// make cache with 10ms TTL and 5 max keys
cache := NewLRU[string, string](5, nil, time.Millisecond*10)
// set value under key1.
cache.Add("key1", "val1")
// get value under key1
r, ok := cache.Get("key1")
// check for OK value
if ok {
fmt.Printf("value before expiration is found: %v, value: %q\n", ok, r)
}
// wait for cache to expire
time.Sleep(time.Millisecond * 100)
// get value under key1 after key expiration
r, ok = cache.Get("key1")
fmt.Printf("value after expiration is found: %v, value: %q\n", ok, r)
// set value under key2, would evict old entry because it is already expired.
cache.Add("key2", "val2")
fmt.Printf("Cache len: %d\n", cache.Len())
Output: value before expiration is found: true, value: "val1" value after expiration is found: false, value: "" Cache len: 1
func NewLRU ¶
func NewLRU[K comparable, V any](size int, onEvict EvictCallback[K, V], ttl time.Duration) *LRU[K, V]
NewLRU returns a new thread-safe cache with expirable entries.
Size parameter set to 0 makes cache of unlimited size, e.g. turns LRU mechanism off.
Providing 0 TTL turns expiring off.
Delete expired entries every 1/100th of ttl value. Goroutine which deletes expired entries runs indefinitely.
func (*LRU[K, V]) Add ¶
Add adds a value to the cache. Returns true if an eviction occurred. Returns false if there was no eviction: the item was already in the cache, or the size was not exceeded.
func (*LRU[K, V]) Contains ¶
Contains checks if a key is in the cache, without updating the recent-ness or deleting it for being stale.
func (*LRU[K, V]) Keys ¶
func (c *LRU[K, V]) Keys() []K
Keys returns a slice of the keys in the cache, from oldest to newest.
func (*LRU[K, V]) Peek ¶
Peek returns the key value (or undefined if not found) without updating the "recently used"-ness of the key.
func (*LRU[K, V]) Purge ¶
func (c *LRU[K, V]) Purge()
Purge clears the cache completely. onEvict is called for each evicted key.
func (*LRU[K, V]) Remove ¶
Remove removes the provided key from the cache, returning if the key was contained.
func (*LRU[K, V]) RemoveOldest ¶
RemoveOldest removes the oldest item from the cache.
Source Files