111 lines
2.6 KiB
Go
111 lines
2.6 KiB
Go
|
package lru
|
||
|
|
|
||
|
|
import (
|
||
|
|
"sync"
|
||
|
|
|
||
|
|
"github.com/hashicorp/golang-lru/simplelru"
|
||
|
|
)
|
||
|
|
|
||
|
|
// Cache is a thread-safe fixed size LRU cache.
|
||
|
|
type Cache struct {
|
||
|
|
lru simplelru.LRUCache
|
||
|
|
lock sync.RWMutex
|
||
|
|
}
|
||
|
|
|
||
|
|
// New creates an LRU of the given size.
|
||
|
|
func New(size int) (*Cache, error) {
|
||
|
|
return NewWithEvict(size, nil)
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewWithEvict constructs a fixed size cache with the given eviction
|
||
|
|
// callback.
|
||
|
|
func NewWithEvict(size int, onEvicted func(key interface{}, value interface{})) (*Cache, error) {
|
||
|
|
lru, err := simplelru.NewLRU(size, simplelru.EvictCallback(onEvicted))
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
c := &Cache{
|
||
|
|
lru: lru,
|
||
|
|
}
|
||
|
|
return c, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Purge is used to completely clear the cache.
|
||
|
|
func (c *Cache) Purge() {
|
||
|
|
c.lock.Lock()
|
||
|
|
c.lru.Purge()
|
||
|
|
c.lock.Unlock()
|
||
|
|
}
|
||
|
|
|
||
|
|
// Add adds a value to the cache. Returns true if an eviction occurred.
|
||
|
|
func (c *Cache) Add(key, value interface{}) (evicted bool) {
|
||
|
|
c.lock.Lock()
|
||
|
|
defer c.lock.Unlock()
|
||
|
|
return c.lru.Add(key, value)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Get looks up a key's value from the cache.
|
||
|
|
func (c *Cache) Get(key interface{}) (value interface{}, ok bool) {
|
||
|
|
c.lock.Lock()
|
||
|
|
defer c.lock.Unlock()
|
||
|
|
return c.lru.Get(key)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Contains checks if a key is in the cache, without updating the
|
||
|
|
// recent-ness or deleting it for being stale.
|
||
|
|
func (c *Cache) Contains(key interface{}) bool {
|
||
|
|
c.lock.RLock()
|
||
|
|
defer c.lock.RUnlock()
|
||
|
|
return c.lru.Contains(key)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Peek returns the key value (or undefined if not found) without updating
|
||
|
|
// the "recently used"-ness of the key.
|
||
|
|
func (c *Cache) Peek(key interface{}) (value interface{}, ok bool) {
|
||
|
|
c.lock.RLock()
|
||
|
|
defer c.lock.RUnlock()
|
||
|
|
return c.lru.Peek(key)
|
||
|
|
}
|
||
|
|
|
||
|
|
// ContainsOrAdd checks if a key is in the cache without updating the
|
||
|
|
// recent-ness or deleting it for being stale, and if not, adds the value.
|
||
|
|
// Returns whether found and whether an eviction occurred.
|
||
|
|
func (c *Cache) ContainsOrAdd(key, value interface{}) (ok, evicted bool) {
|
||
|
|
c.lock.Lock()
|
||
|
|
defer c.lock.Unlock()
|
||
|
|
|
||
|
|
if c.lru.Contains(key) {
|
||
|
|
return true, false
|
||
|
|
}
|
||
|
|
evicted = c.lru.Add(key, value)
|
||
|
|
return false, evicted
|
||
|
|
}
|
||
|
|
|
||
|
|
// Remove removes the provided key from the cache.
|
||
|
|
func (c *Cache) Remove(key interface{}) {
|
||
|
|
c.lock.Lock()
|
||
|
|
c.lru.Remove(key)
|
||
|
|
c.lock.Unlock()
|
||
|
|
}
|
||
|
|
|
||
|
|
// RemoveOldest removes the oldest item from the cache.
|
||
|
|
func (c *Cache) RemoveOldest() {
|
||
|
|
c.lock.Lock()
|
||
|
|
c.lru.RemoveOldest()
|
||
|
|
c.lock.Unlock()
|
||
|
|
}
|
||
|
|
|
||
|
|
// Keys returns a slice of the keys in the cache, from oldest to newest.
|
||
|
|
func (c *Cache) Keys() []interface{} {
|
||
|
|
c.lock.RLock()
|
||
|
|
defer c.lock.RUnlock()
|
||
|
|
return c.lru.Keys()
|
||
|
|
}
|
||
|
|
|
||
|
|
// Len returns the number of items in the cache.
|
||
|
|
func (c *Cache) Len() int {
|
||
|
|
c.lock.RLock()
|
||
|
|
defer c.lock.RUnlock()
|
||
|
|
return c.lru.Len()
|
||
|
|
}
|