Add DeleteFunc

This shares DeletePrefixs's implementation.

bucket.go

@@ -54,13 +54,13 @@ func (b *bucket) delete(key string) *Item {
 // the item from the map. I'm pretty sure this is 100% fine, but it is unique.
 // (We do this so that the write to the channel is under the read lock and not the
 // write lock)
-func (b *bucket) deletePrefix(prefix string, deletables chan *Item) int {
+func (b *bucket) deleteFunc(matches func(key string, item interface{}) bool, deletables chan *Item) int {
 	lookup := b.lookup
 	items := make([]*Item, 0, len(lookup)/10)
 
 	b.RLock()
 	for key, item := range lookup {
-		if strings.HasPrefix(key, prefix) {
+		if matches(key, item) {
 			deletables <- item
 			items = append(items, item)
 		}
@@ -80,6 +80,12 @@ func (b *bucket) deletePrefix(prefix string, deletables chan *Item) int {
 	return len(items)
 }
 
+func (b *bucket) deletePrefix(prefix string, deletables chan *Item) int {
+	return b.deleteFunc(func(key string, item interface{}) bool {
+		return strings.HasPrefix(key, prefix)
+	}, deletables)
+}
+
 func (b *bucket) clear() {
 	b.Lock()
 	b.lookup = make(map[string]*Item)

cache.go

@@ -63,6 +63,15 @@ func (c *Cache) DeletePrefix(prefix string) int {
 	return count
 }
 
+// Deletes all items that the matches func evaluates to true.
+func (c *Cache) DeleteFunc(matches func(key string, item interface{}) bool) int {
+	count := 0
+	for _, b := range c.buckets {
+		count += b.deleteFunc(matches, c.deletables)
+	}
+	return count
+}
+
 // Get an item from the cache. Returns nil if the item wasn't found.
 // This can return an expired item. Use item.Expired() to see if the item
 // is expired and item.TTL() to see how long until the item expires (which

cache_test.go

@@ -51,6 +51,35 @@ func (_ CacheTests) DeletesAPrefix() {
 	Expect(cache.ItemCount()).To.Equal(2)
 }
 
+func (_ CacheTests) DeletesAFunc() {
+	cache := New(Configure())
+	Expect(cache.ItemCount()).To.Equal(0)
+
+	cache.Set("a", 1, time.Minute)
+	cache.Set("b", 2, time.Minute)
+	cache.Set("c", 3, time.Minute)
+	cache.Set("d", 4, time.Minute)
+	cache.Set("e", 5, time.Minute)
+	cache.Set("f", 6, time.Minute)
+	Expect(cache.ItemCount()).To.Equal(6)
+
+	Expect(cache.DeleteFunc(func(key string, item interface{}) bool {
+		return false
+	})).To.Equal(0)
+	Expect(cache.ItemCount()).To.Equal(6)
+
+	Expect(cache.DeleteFunc(func(key string, item interface{}) bool {
+		return item.(*Item).Value().(int) < 4
+	})).To.Equal(3)
+	Expect(cache.ItemCount()).To.Equal(3)
+
+	Expect(cache.DeleteFunc(func(key string, item interface{}) bool {
+		return key == "d"
+	})).To.Equal(1)
+	Expect(cache.ItemCount()).To.Equal(2)
+
+}
+
 func (_ CacheTests) OnDeleteCallbackCalled() {
 	onDeleteFnCalled := false
 	onDeleteFn := func(item *Item) {

layeredbucket.go

@@ -71,6 +71,16 @@ func (b *layeredBucket) deletePrefix(primary, prefix string, deletables chan *It
 	return bucket.deletePrefix(prefix, deletables)
 }
 
+func (b *layeredBucket) deleteFunc(primary string, matches func(key string, item interface{}) bool, deletables chan *Item) int {
+	b.RLock()
+	bucket, exists := b.buckets[primary]
+	b.RUnlock()
+	if exists == false {
+		return 0
+	}
+	return bucket.deleteFunc(matches, deletables)
+}
+
 func (b *layeredBucket) deleteAll(primary string, deletables chan *Item) bool {
 	b.RLock()
 	bucket, exists := b.buckets[primary]

layeredcache.go

@@ -154,6 +154,11 @@ func (c *LayeredCache) DeletePrefix(primary, prefix string) int {
 	return c.bucket(primary).deletePrefix(primary, prefix, c.deletables)
 }
 
+// Deletes all items that share the same primary key and where the matches func evaluates to true.
+func (c *LayeredCache) DeleteFunc(primary string, matches func(key string, item interface{}) bool) int {
+	return c.bucket(primary).deleteFunc(primary, matches, c.deletables)
+}
+
 //this isn't thread safe. It's meant to be called from non-concurrent tests
 func (c *LayeredCache) Clear() {
 	for _, bucket := range c.buckets {

layeredcache_test.go

@@ -95,6 +95,35 @@ func (_ *LayeredCacheTests) DeletesAPrefix() {
 	Expect(cache.ItemCount()).To.Equal(3)
 }
 
+func (_ *LayeredCacheTests) DeletesAFunc() {
+	cache := newLayered()
+	Expect(cache.ItemCount()).To.Equal(0)
+
+	cache.Set("spice", "a", 1, time.Minute)
+	cache.Set("leto", "b", 2, time.Minute)
+	cache.Set("spice", "c", 3, time.Minute)
+	cache.Set("spice", "d", 4, time.Minute)
+	cache.Set("spice", "e", 5, time.Minute)
+	cache.Set("spice", "f", 6, time.Minute)
+	Expect(cache.ItemCount()).To.Equal(6)
+
+	Expect(cache.DeleteFunc("spice", func(key string, item interface{}) bool {
+		return false
+	})).To.Equal(0)
+	Expect(cache.ItemCount()).To.Equal(6)
+
+	Expect(cache.DeleteFunc("spice", func(key string, item interface{}) bool {
+		return item.(*Item).Value().(int) < 4
+	})).To.Equal(2)
+	Expect(cache.ItemCount()).To.Equal(4)
+
+	Expect(cache.DeleteFunc("spice", func(key string, item interface{}) bool {
+		return key == "d"
+	})).To.Equal(1)
+	Expect(cache.ItemCount()).To.Equal(3)
+
+}
+
 func (_ *LayeredCacheTests) OnDeleteCallbackCalled() {
 
 	onDeleteFnCalled := false