抽取 now 和 hash 到缓存级别

FUTURE.md

@@ -13,9 +13,10 @@
 * [x] 检查 pkg 代码，完善单元测试，提高覆盖率
 * [x] 清理废话注释，完善 examples 和性能测试
 * [x] 增加 report 机制用于监控缓存的情况
+* [x] 提取 now 和 hash 到缓存级别配置
+* [ ] 提供定时缓存时间的机制，可选快速时钟
 * [ ] 增加对不存在的数据做防穿透的机制
 * [ ] 提供一个清空并设置全量值的方法，方便定时数据的全量替换
-* [ ] 提供定时缓存时间的 Clock 功能，可选标准库和快速两种
 
 ### v0.3.x
 

entry.go

@@ -20,12 +20,15 @@ type entry struct {
 	key        string
 	value      interface{}
 	expiration int64 // Time in nanosecond, valid util 2262 year (enough, uh?)
+	now        func() int64
 }
 
-func newEntry(key string, value interface{}, ttl time.Duration) *entry {
-	e := new(entry)
-	e.setup(key, value, ttl)
+func newEntry(key string, value interface{}, ttl time.Duration, now func() int64) *entry {
+	e := &entry{
+		now: now,
+	}
 
+	e.setup(key, value, ttl)
 	return e
 }
 
@@ -35,7 +38,7 @@ func (e *entry) setup(key string, value interface{}, ttl time.Duration) {
 	e.expiration = 0
 
 	if ttl > 0 {
-		e.expiration = Now() + ttl.Nanoseconds()
+		e.expiration = e.now() + ttl.Nanoseconds()
 	}
 }
 
@@ -44,5 +47,5 @@ func (e *entry) expired(now int64) bool {
 		return e.expiration > 0 && e.expiration < now
 	}
 
-	return e.expiration > 0 && e.expiration < Now()
+	return e.expiration > 0 && e.expiration < e.now()
 }

entry_test.go

@@ -15,13 +15,14 @@
 package cachego
 
 import (
+	"fmt"
 	"testing"
 	"time"
 )
 
 // go test -v -cover -run=^TestNewEntry$
 func TestNewEntry(t *testing.T) {
-	e := newEntry("key", "value", 0)
+	e := newEntry("key", "value", 0, now)
 
 	if e.key != "key" {
 		t.Errorf("e.key %s is wrong", e.key)
@@ -35,7 +36,11 @@ func TestNewEntry(t *testing.T) {
 		t.Errorf("e.expiration %+v != 0", e.expiration)
 	}
 
-	e = newEntry("k", "v", time.Second)
+	if fmt.Sprintf("%p", e.now) != fmt.Sprintf("%p", now) {
+		t.Errorf("e.now %p is wrong", e.now)
+	}
+
+	e = newEntry("k", "v", time.Second, now)
 	expiration := time.Now().Add(time.Second).UnixNano()
 
 	if e.key != "k" {
@@ -50,6 +55,10 @@ func TestNewEntry(t *testing.T) {
 		t.Error("e.expiration == 0")
 	}
 
+	if fmt.Sprintf("%p", e.now) != fmt.Sprintf("%p", now) {
+		t.Errorf("e.now %p is wrong", e.now)
+	}
+
 	// Keep one us for code running.
 	if expiration < e.expiration || e.expiration < expiration-time.Microsecond.Nanoseconds() {
 		t.Errorf("e.expiration %d != expiration %d", e.expiration, expiration)
@@ -58,7 +67,7 @@ func TestNewEntry(t *testing.T) {
 
 // go test -v -cover -run=^TestEntrySetup$
 func TestEntrySetup(t *testing.T) {
-	e := newEntry("key", "value", 0)
+	e := newEntry("key", "value", 0, now)
 
 	if e.key != "key" {
 		t.Errorf("e.key %s is wrong", e.key)
@@ -100,7 +109,7 @@ func TestEntrySetup(t *testing.T) {
 
 // go test -cover -run=^TestEntryExpired$
 func TestEntryExpired(t *testing.T) {
-	e := newEntry("", nil, time.Millisecond)
+	e := newEntry("", nil, time.Millisecond, now)
 
 	if e.expired(0) {
 		t.Error("e should be unexpired!")

global.go

@@ -17,19 +17,8 @@ package cachego
 import "time"
 
 var (
-	// MapInitialCap is the initial capacity of map.
-	MapInitialCap = 64
-
-	// SliceInitialCap is the initial capacity of slice.
-	SliceInitialCap = 64
-)
-
-var (
-	// Hash returns the hash code of one key.
-	Hash = hash
-
-	// Now returns the current time in nanosecond.
-	Now = now
+	mapInitialCap   = 64
+	sliceInitialCap = 64
 )
 
 func hash(key string) int {
@@ -46,3 +35,17 @@ func hash(key string) int {
 func now() int64 {
 	return time.Now().UnixNano()
 }
+
+// SetMapInitialCap sets the initial capacity of map.
+func SetMapInitialCap(initialCap int) {
+	if initialCap > 0 {
+		mapInitialCap = initialCap
+	}
+}
+
+// SetSliceInitialCap sets the initial capacity of slice.
+func SetSliceInitialCap(initialCap int) {
+	if initialCap > 0 {
+		sliceInitialCap = initialCap
+	}
+}

global_test.go

@@ -25,24 +25,64 @@ func BenchmarkHash(b *testing.B) {
 	b.ResetTimer()
 
 	for i := 0; i < b.N; i++ {
-		Hash("key")
+		hash("key")
 	}
 }
 
 // go test -v -cover -run=^TestHash$
 func TestHash(t *testing.T) {
-	hash := Hash("test")
-	if hash <= 0 {
+	hash := hash("test")
+	if hash < 0 {
 		t.Errorf("hash %d <= 0", hash)
 	}
 }
 
 // go test -v -cover -run=^TestNow$
 func TestNow(t *testing.T) {
-	got := Now()
+	got := now()
 	expect := time.Now().UnixNano()
 
 	if got > expect || got < expect-time.Microsecond.Nanoseconds() {
 		t.Errorf("got %d != expect %d", got, expect)
 	}
 }
+
+// go test -v -cover -run=^TestSetMapInitialCap$
+func TestSetMapInitialCap(t *testing.T) {
+	oldInitialCap := mapInitialCap
+
+	SetMapInitialCap(-2)
+	if mapInitialCap != oldInitialCap {
+		t.Errorf("mapInitialCap %d is wrong", mapInitialCap)
+	}
+
+	SetMapInitialCap(0)
+	if mapInitialCap != oldInitialCap {
+		t.Errorf("mapInitialCap %d is wrong", mapInitialCap)
+	}
+
+	SetMapInitialCap(2)
+	if mapInitialCap != 2 {
+		t.Errorf("mapInitialCap %d is wrong", mapInitialCap)
+	}
+}
+
+// go test -v -cover -run=^TestSetSliceInitialCap$
+func TestSetSliceInitialCap(t *testing.T) {
+	oldInitialCap := sliceInitialCap
+
+	SetSliceInitialCap(-2)
+	if sliceInitialCap != oldInitialCap {
+		t.Errorf("sliceInitialCap %d is wrong", sliceInitialCap)
+	}
+
+	SetSliceInitialCap(0)
+	if sliceInitialCap != oldInitialCap {
+		t.Errorf("sliceInitialCap %d is wrong", sliceInitialCap)
+	}
+
+	SetSliceInitialCap(2)
+	if sliceInitialCap != 2 {
+		t.Errorf("sliceInitialCap %d is wrong", sliceInitialCap)
+	}
+}

lfu.go

@@ -33,8 +33,8 @@ func newLFUCache(conf *config) Cache {
 	}
 
 	cache := &lfuCache{
-		itemMap:  make(map[string]*heap.Item, MapInitialCap),
-		itemHeap: heap.New(SliceInitialCap),
+		itemMap:  make(map[string]*heap.Item, mapInitialCap),
+		itemHeap: heap.New(sliceInitialCap),
 	}
 
 	cache.setup(conf, cache)
@@ -87,7 +87,7 @@ func (lc *lfuCache) set(key string, value interface{}, ttl time.Duration) (evict
 		evictedValue = lc.evict()
 	}
 
-	item = lc.itemHeap.Push(0, newEntry(key, value, ttl))
+	item = lc.itemHeap.Push(0, newEntry(key, value, ttl, lc.now))
 	lc.itemMap[key] = item
 
 	return evictedValue
@@ -115,7 +115,7 @@ func (lc *lfuCache) size() (size int) {
 }
 
 func (lc *lfuCache) gc() (cleans int) {
-	now := Now()
+	now := lc.now()
 	scans := 0
 
 	for _, item := range lc.itemMap {
@@ -135,8 +135,8 @@ func (lc *lfuCache) gc() (cleans int) {
 }
 
 func (lc *lfuCache) reset() {
-	lc.itemMap = make(map[string]*heap.Item, MapInitialCap)
-	lc.itemHeap = heap.New(SliceInitialCap)
+	lc.itemMap = make(map[string]*heap.Item, mapInitialCap)
+	lc.itemHeap = heap.New(sliceInitialCap)
 	lc.Loader.Reset()
 }
 

load.go

@@ -47,7 +47,7 @@ func NewLoader(cache Cache, enableSingleflight bool) Loader {
 	}
 
 	if enableSingleflight {
-		loader.group = singleflight.NewGroup(MapInitialCap)
+		loader.group = singleflight.NewGroup(mapInitialCap)
 	}
 
 	return loader

lru.go

@@ -32,7 +32,7 @@ func newLRUCache(conf *config) Cache {
 	}
 
 	cache := &lruCache{
-		elementMap:  make(map[string]*list.Element, MapInitialCap),
+		elementMap:  make(map[string]*list.Element, mapInitialCap),
 		elementList: list.New(),
 	}
 
@@ -86,7 +86,7 @@ func (lc *lruCache) set(key string, value interface{}, ttl time.Duration) (evict
 		evictedValue = lc.evict()
 	}
 
-	element = lc.elementList.PushFront(newEntry(key, value, ttl))
+	element = lc.elementList.PushFront(newEntry(key, value, ttl, lc.now))
 	lc.elementMap[key] = element
 
 	return evictedValue
@@ -114,7 +114,7 @@ func (lc *lruCache) size() (size int) {
 }
 
 func (lc *lruCache) gc() (cleans int) {
-	now := Now()
+	now := lc.now()
 	scans := 0
 
 	for _, element := range lc.elementMap {
@@ -134,7 +134,7 @@ func (lc *lruCache) gc() (cleans int) {
 }
 
 func (lc *lruCache) reset() {
-	lc.elementMap = make(map[string]*list.Element, MapInitialCap)
+	lc.elementMap = make(map[string]*list.Element, mapInitialCap)
 	lc.elementList = list.New()
 	lc.Loader.Reset()
 }

option.go

@@ -27,6 +27,9 @@ type config struct {
 	maxScans   int
 	maxEntries int
 
+	now  func() int64
+	hash func(key string) int
+
 	reportMissed func(key string)
 	reportHit    func(key string, value interface{})
 	reportGC     func(cost time.Duration, cleans int)
@@ -41,6 +44,8 @@ func newDefaultConfig() *config {
 		gcDuration:   0,
 		maxScans:     10000,
 		maxEntries:   0,
+		now:          now,
+		hash:         hash,
 	}
 }
 
@@ -122,6 +127,26 @@ func WithMaxEntries(maxEntries int) Option {
 	}
 }
 
+// WithNow returns an option setting the now function of cache.
+// A now function should return a nanosecond unix time.
+func WithNow(now func() int64) Option {
+	return func(conf *config) {
+		if now != nil {
+			conf.now = now
+		}
+	}
+}
+
+// WithHash returns an option setting the hash function of cache.
+// A hash function should return the hash code of key.
+func WithHash(hash func(key string) int) Option {
+	return func(conf *config) {
+		if hash != nil {
+			conf.hash = hash
+		}
+	}
+}
+
 // WithReportMissed returns an option setting the reportMissed of cache.
 func WithReportMissed(reportMissed func(key string)) Option {
 	return func(conf *config) {

option_test.go

@@ -45,6 +45,14 @@ func isConfigEquals(conf1 *config, conf2 *config) bool {
 		return false
 	}
 
+	if fmt.Sprintf("%p", conf1.now) != fmt.Sprintf("%p", conf2.now) {
+		return false
+	}
+
+	if fmt.Sprintf("%p", conf1.hash) != fmt.Sprintf("%p", conf2.hash) {
+		return false
+	}
+
 	if fmt.Sprintf("%p", conf1.reportMissed) != fmt.Sprintf("%p", conf2.reportMissed) {
 		return false
 	}
@@ -172,6 +180,36 @@ func TestWithMaxEntries(t *testing.T) {
 	}
 }
 
+// go test -v -cover -run=^TestWithNow$
+func TestWithNow(t *testing.T) {
+	now := func() int64 {
+		return 0
+	}
+
+	got := &config{now: nil}
+	expect := &config{now: now}
+
+	WithNow(now).applyTo(got)
+	if !isConfigEquals(got, expect) {
+		t.Errorf("got %+v != expect %+v", got, expect)
+	}
+}
+
+// go test -v -cover -run=^TestWithHash$
+func TestWithHash(t *testing.T) {
+	hash := func(key string) int {
+		return 0
+	}
+
+	got := &config{hash: nil}
+	expect := &config{hash: hash}
+
+	WithHash(hash).applyTo(got)
+	if !isConfigEquals(got, expect) {
+		t.Errorf("got %+v != expect %+v", got, expect)
+	}
+}
+
 // go test -v -cover -run=^TestWithReportMissed$
 func TestWithReportMissed(t *testing.T) {
 	reportMissed := func(key string) {}