From 3f777bf16ffb019c970aee4bd550bfe3c38aa6bb Mon Sep 17 00:00:00 2001
From: Radu Ioan Fericean <radu@fericean.ro>
Date: Wed, 17 Aug 2016 14:16:11 +0300
Subject: [PATCH] cache improvements

---
 cache2go/lruttl.go | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/cache2go/lruttl.go b/cache2go/lruttl.go
index 0afa04982..d96b81776 100644
--- a/cache2go/lruttl.go
+++ b/cache2go/lruttl.go
@@ -13,10 +13,6 @@ type Cache struct {
 	// an item is evicted. Zero means no limit.
 	maxEntries int
 
-	// OnEvicted optionally specificies a callback function to be
-	// executed when an entry is purged from the cache.
-	OnEvicted func(key string, value interface{})
-
 	lruIndex   *list.List
 	ttlIndex   []*list.Element
 	cache      map[string]*list.Element
@@ -37,10 +33,10 @@ func NewLRUTTL(maxEntries int, expire time.Duration) *Cache {
 		maxEntries: maxEntries,
 		expiration: expire,
 		lruIndex:   list.New(),
-		ttlIndex:   make([]*list.Element, 0),
 		cache:      make(map[string]*list.Element),
 	}
 	if c.expiration > 0 {
+		c.ttlIndex = make([]*list.Element, 0)
 		go c.cleanExpired()
 	}
 	return c
@@ -75,7 +71,9 @@ func (c *Cache) Set(key string, value interface{}) {
 	if c.cache == nil {
 		c.cache = make(map[string]*list.Element)
 		c.lruIndex = list.New()
-		c.ttlIndex = make([]*list.Element, 0)
+		if c.expiration > 0 {
+			c.ttlIndex = make([]*list.Element, 0)
+		}
 	}
 
 	if e, ok := c.cache[key]; ok {
@@ -89,7 +87,9 @@ func (c *Cache) Set(key string, value interface{}) {
 		return
 	}
 	e := c.lruIndex.PushFront(&entry{key: key, value: value, timestamp: time.Now()})
-	c.ttlIndex = append(c.ttlIndex, e)
+	if c.expiration > 0 {
+		c.ttlIndex = append(c.ttlIndex, e)
+	}
 	c.cache[key] = e
 	c.mu.Unlock()
 
@@ -107,7 +107,7 @@ func (c *Cache) Get(key string) (value interface{}, ok bool) {
 	}
 	if e, hit := c.cache[key]; hit {
 		c.lruIndex.MoveToFront(e)
-		e.Value.(*entry).timestamp = time.Now()
+		//e.Value.(*entry).timestamp = time.Now() don't update the timestamp on get'
 		return e.Value.(*entry).value, true
 	}
 	return
@@ -153,9 +153,6 @@ func (c *Cache) removeElement(e *list.Element) {
 	}
 	kv := e.Value.(*entry)
 	delete(c.cache, kv.key)
-	if c.OnEvicted != nil {
-		c.OnEvicted(kv.key, kv.value)
-	}
 }
 
 // Len returns the number of items in the cache.
@@ -173,6 +170,8 @@ func (c *Cache) Flush() {
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	c.lruIndex = list.New()
-	c.ttlIndex = make([]*list.Element, 0)
+	if c.expiration > 0 {
+		c.ttlIndex = make([]*list.Element, 0)
+	}
 	c.cache = make(map[string]*list.Element)
 }