renamed MaxItems to MaxSize, updated readme

cache.go

@@ -145,7 +145,7 @@ func (c *Cache) worker() {
 	for {
 		select {
 		case item := <-c.promotables:
-			if c.doPromote(item) && atomic.LoadInt64(&c.size) > c.maxItems {
+			if c.doPromote(item) && atomic.LoadInt64(&c.size) > c.maxSize {
 				c.gc()
 			}
 		case item := <-c.deletables:

cache_test.go

@@ -64,7 +64,7 @@ func (_ CacheTests) TrackerDoesNotCleanupHeldInstance() {
 }
 
 func (_ CacheTests) RemovesOldestItemWhenFull() {
-	cache := New(Configure().MaxItems(5).ItemsToPrune(1))
+	cache := New(Configure().MaxSize(5).ItemsToPrune(1))
 	for i := 0; i < 7; i++ {
 		cache.Set(strconv.Itoa(i), i, time.Minute)
 	}
@@ -75,7 +75,7 @@ func (_ CacheTests) RemovesOldestItemWhenFull() {
 }
 
 func (_ CacheTests) RemovesOldestItemWhenFullBySizer() {
-	cache := New(Configure().MaxItems(9).ItemsToPrune(2))
+	cache := New(Configure().MaxSize(9).ItemsToPrune(2))
 	for i := 0; i < 7; i++ {
 		cache.Set(strconv.Itoa(i), &SizedItem{i, 2}, time.Minute)
 	}

configuration.go

@@ -1,7 +1,7 @@
 package ccache
 
 type Configuration struct {
-	maxItems       int64
+	maxSize        int64
 	buckets        int
 	itemsToPrune   int
 	deleteBuffer   int
@@ -12,7 +12,7 @@ type Configuration struct {
 
 // Creates a configuration object with sensible defaults
 // Use this as the start of the fluent configuration:
-// e.g.: ccache.New(ccache.Configure().MaxItems(10000))
+// e.g.: ccache.New(ccache.Configure().MaxSize(10000))
 func Configure() *Configuration {
 	return &Configuration{
 		buckets:        16,
@@ -20,15 +20,15 @@ func Configure() *Configuration {
 		deleteBuffer:   1024,
 		getsPerPromote: 3,
 		promoteBuffer:  1024,
-		maxItems:       5000,
+		maxSize:        5000,
 		tracking:       false,
 	}
 }
 
-// The max number of items to store in the cache
+// The max size for the cache
 // [5000]
-func (c *Configuration) MaxItems(max int64) *Configuration {
-	c.maxItems = max
+func (c *Configuration) MaxSize(max int64) *Configuration {
+	c.maxSize = max
 	return c
 }
 

layeredcache.go

@@ -156,7 +156,7 @@ func (c *LayeredCache) worker() {
 	for {
 		select {
 		case item := <-c.promotables:
-			if c.doPromote(item) && atomic.LoadInt64(&c.size) > c.maxItems {
+			if c.doPromote(item) && atomic.LoadInt64(&c.size) > c.maxSize {
 				c.gc()
 			}
 		case item := <-c.deletables:

layeredcache_test.go

@@ -124,7 +124,7 @@ func (_ LayeredCacheTests) TrackerDoesNotCleanupHeldInstance() {
 }
 
 func (_ LayeredCacheTests) RemovesOldestItemWhenFull() {
-	cache := Layered(Configure().MaxItems(5).ItemsToPrune(1))
+	cache := Layered(Configure().MaxSize(5).ItemsToPrune(1))
 	cache.Set("xx", "a", 23, time.Minute)
 	for i := 0; i < 7; i++ {
 		cache.Set(strconv.Itoa(i), "a", i, time.Minute)
@@ -144,7 +144,7 @@ func newLayered() *LayeredCache {
 }
 
 func (_ LayeredCacheTests) RemovesOldestItemWhenFullBySizer() {
-	cache := Layered(Configure().MaxItems(9).ItemsToPrune(2))
+	cache := Layered(Configure().MaxSize(9).ItemsToPrune(2))
 	for i := 0; i < 7; i++ {
 		cache.Set("pri", strconv.Itoa(i), &SizedItem{i, 2}, time.Minute)
 	}

readme.md

@@ -28,14 +28,14 @@ var cache = ccache.New(ccache.Configure())
 `Configure` exposes a chainable API:
 
 ```go
-var cache = ccache.New(ccache.Configure().MaxItems(1000).itemsToPrune(100))
+var cache = ccache.New(ccache.Configure().MaxSize(1000).itemsToPrune(100))
 ```
 
 The most likely configuration options to tweak are:
 
-* `MaxItems(int)` - the maximum number of items to store in the cache (default: 5000)
+* `MaxSize(int)` - the maximum number size  to store in the cache (default: 5000)
 * `GetsPerPromote(int)` - the number of times an item is fetched before we promote it. For large caches with long TTLs, it normally isn't necessary to promote an item after every fetch (default: 3)
-* `ItemsToPrune(int)` - the number of items to prune when we hit `MaxItems`. Freeing up more than 1 slot at a time improved performance (default: 500)
+* `ItemsToPrune(int)` - the number of items to prune when we hit `MaxSize`. Freeing up more than 1 slot at a time improved performance (default: 500)
 
 Configurations that change the internals of the cache, which aren't as likely to need tweaking:
 
@@ -146,3 +146,7 @@ cache.Delete("/users/goku", "type:xml")
 // OR
 cache.DeleteAll("/users/goku")
 ```
+## Size
+By default, items added to a cache have a size of 1. This means that if you configure `MaxSize(10000)`, you'll be able to store 10000 items in the cache.
+
+However, if the values you set into the cache have a method `Size() int64`, this size will be used. Note that ccache has an overhead of ~350 bytes per entry, which isn't taken into account. In other words, given a filled up cache, with `MaxSize(4096000)` and items that return a `Size() int64` of 2048, we can expect to find 2000 items (4096000/2048) taking a total space of 4796000 bytes.