add Values() method to get cache values (#94)

* add Values() method to get cache values

* Update against generics

---------

Co-authored-by: Jeff Mitchell <jeffrey.mitchell@gmail.com>

2q.go

@@ -181,6 +181,16 @@ func (c *TwoQueueCache[K, V]) Keys() []K {
 	return append(k1, k2...)
 }
 
+// Values returns a slice of the values in the cache.
+// The frequently used values are first in the returned slice.
+func (c *TwoQueueCache[K, V]) Values() []V {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	v1 := c.frequent.Values()
+	v2 := c.recent.Values()
+	return append(v1, v2...)
+}
+
 // Remove removes the provided key from the cache.
 func (c *TwoQueueCache[K, V]) Remove(key K) {
 	c.lock.Lock()

2q_test.go

@@ -236,6 +236,11 @@ func Test2Q(t *testing.T) {
 			t.Fatalf("bad key: %v", k)
 		}
 	}
+	for i, v := range l.Values() {
+		if v != i+128 {
+			t.Fatalf("bad key: %v", v)
+		}
+	}
 	for i := 0; i < 128; i++ {
 		if _, ok := l.Get(i); ok {
 			t.Fatalf("should be evicted")

arc.go

@@ -211,6 +211,15 @@ func (c *ARCCache[K, V]) Keys() []K {
 	return append(k1, k2...)
 }
 
+// Values returns all the cached values
+func (c *ARCCache[K, V]) Values() []V {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	v1 := c.t1.Values()
+	v2 := c.t2.Values()
+	return append(v1, v2...)
+}
+
 // Remove is used to purge a key from the cache
 func (c *ARCCache[K, V]) Remove(key K) {
 	c.lock.Lock()

arc_test.go

@@ -308,6 +308,11 @@ func TestARC(t *testing.T) {
 			t.Fatalf("bad key: %v", k)
 		}
 	}
+	for i, v := range l.Values() {
+		if v != i+128 {
+			t.Fatalf("bad value: %v", v)
+		}
+	}
 	for i := 0; i < 128; i++ {
 		if _, ok := l.Get(i); ok {
 			t.Fatalf("should be evicted")

lru.go

@@ -233,6 +233,14 @@ func (c *Cache[K, V]) Keys() []K {
 	return keys
 }
 
+// Values returns a slice of the values in the cache, from oldest to newest.
+func (c *Cache[K, V]) Values() []V {
+	c.lock.RLock()
+	values := c.lru.Values()
+	c.lock.RUnlock()
+	return values
+}
+
 // Len returns the number of items in the cache.
 func (c *Cache[K, V]) Len() int {
 	c.lock.RLock()

lru_test.go

@@ -95,6 +95,11 @@ func TestLRU(t *testing.T) {
 			t.Fatalf("bad key: %v", k)
 		}
 	}
+	for i, v := range l.Values() {
+		if v != i+128 {
+			t.Fatalf("bad value: %v", v)
+		}
+	}
 	for i := 0; i < 128; i++ {
 		if _, ok := l.Get(i); ok {
 			t.Fatalf("should be evicted")

simplelru/lru.go

@@ -129,6 +129,17 @@ func (c *LRU[K, V]) Keys() []K {
 	return keys
 }
 
+// Values returns a slice of the values in the cache, from oldest to newest.
+func (c *LRU[K, V]) Values() []V {
+	values := make([]V, len(c.items))
+	i := 0
+	for ent := c.evictList.back(); ent != nil; ent = ent.prevEntry() {
+		values[i] = ent.value
+		i++
+	}
+	return values
+}
+
 // Len returns the number of items in the cache.
 func (c *LRU[K, V]) Len() int {
 	return c.evictList.length()

simplelru/lru_interface.go

@@ -32,6 +32,9 @@ type LRUCache[K comparable, V any] interface {
 	// Returns a slice of the keys in the cache, from oldest to newest.
 	Keys() []K
 
+	// Values returns a slice of the values in the cache, from oldest to newest.
+	Values() []V
+
 	// Returns the number of items in the cache.
 	Len() int
 

simplelru/lru_test.go

@@ -34,6 +34,11 @@ func TestLRU(t *testing.T) {
 			t.Fatalf("bad key: %v", k)
 		}
 	}
+	for i, v := range l.Values() {
+		if v != i+128 {
+			t.Fatalf("bad value: %v", v)
+		}
+	}
 	for i := 0; i < 128; i++ {
 		if _, ok := l.Get(i); ok {
 			t.Fatalf("should be evicted")