From 71bfe9e7093f718514cd9ed7fccbbd096bdbade8 Mon Sep 17 00:00:00 2001
From: Pranjal Pandit <pranjal5215@gmail.com>
Date: Thu, 15 Sep 2016 18:47:54 +0530
Subject: [PATCH] cache changes for evictBulk

---
 cache.go | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/cache.go b/cache.go
index f214480..512e61d 100644
--- a/cache.go
+++ b/cache.go
@@ -42,6 +42,7 @@ type cache struct {
 	items             map[string]Item
 	mu                sync.RWMutex
 	onEvicted         func(string, interface{})
+	onEvictedBulk     func([]KeyAndValue)
 	janitor           *janitor
 }
 
@@ -902,14 +903,14 @@ func (c *cache) delete(k string) (interface{}, bool) {
 	return nil, false
 }
 
-type keyAndValue struct {
-	key   string
-	value interface{}
+type KeyAndValue struct {
+	Key   string
+	Value interface{}
 }
 
 // Delete all expired items from the cache.
 func (c *cache) DeleteExpired() {
-	var evictedItems []keyAndValue
+	var evictedItems []KeyAndValue
 	now := time.Now().UnixNano()
 	c.mu.Lock()
 	for k, v := range c.items {
@@ -917,13 +918,20 @@ func (c *cache) DeleteExpired() {
 		if v.Expiration > 0 && now > v.Expiration {
 			ov, evicted := c.delete(k)
 			if evicted {
-				evictedItems = append(evictedItems, keyAndValue{k, ov})
+				evictedItems = append(evictedItems, KeyAndValue{k, ov})
 			}
 		}
 	}
 	c.mu.Unlock()
-	for _, v := range evictedItems {
-		c.onEvicted(v.key, v.value)
+	// Call evict functions only when
+	// their respective functions exist.
+	if c.onEvictedBulk != nil{
+		c.onEvictedBulk(evictedItems)
+	}else if c.onEvicted != nil{
+		for _, v := range evictedItems {
+			c.onEvicted(v.Key, v.Value)
+		}
+	}else{
 	}
 }
 
@@ -936,6 +944,15 @@ func (c *cache) OnEvicted(f func(string, interface{})) {
 	c.mu.Unlock()
 }
 
+// Set an optional OnEvictedBulk which will be used to evict keys in bulk
+// This is used when eviction happens in bulk when expiry is checked at
+// regular intervals, we dont want to call onEvict multiple times
+func (c *cache) OnEvictedBulk(f func([]KeyAndValue)) {
+	c.mu.Lock()
+	c.onEvictedBulk = f
+	c.mu.Unlock()
+}
+
 // Write the cache's items (using Gob) to an io.Writer.
 //
 // NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the