Rewrite sharde cache to generic one

sharded.go

@@ -8,6 +8,8 @@ import (
 	"os"
 	"runtime"
 	"time"
+
+	"golang.org/x/exp/constraints"
 )
 
 // This is an experimental and unexported (for now) attempt at making a cache
@@ -19,15 +21,15 @@ import (
 //
 // See cache_test.go for a few benchmarks.
 
-type unexportedShardedCache struct {
+type unexportedShardedCache[V constraints.Ordered] struct {
-	*shardedCache
+	*shardedCache[V]
 }
 
-type shardedCache struct {
+type shardedCache[V constraints.Ordered] struct {
 	seed    uint32
 	m       uint32
-	cs      []*cache
+	cs      []*orderedCache[string, V]
-	janitor *shardedJanitor
+	janitor *shardedJanitor[V]
 }
 
 // djb2 with better shuffling. 5x faster than FNV with the hash.Hash overhead.
@@ -62,43 +64,36 @@ func djb33(seed uint32, k string) uint32 {
 	return d ^ (d >> 16)
 }
 
-func (sc *shardedCache) bucket(k string) *cache {
+func (sc *shardedCache[V]) bucket(k string) *orderedCache[string, V] {
 	return sc.cs[djb33(sc.seed, k)%sc.m]
 }
 
-func (sc *shardedCache) Set(k string, x interface{}, d time.Duration) {
+func (sc *shardedCache[V]) Set(k string, x V, d time.Duration) {
 	sc.bucket(k).Set(k, x, d)
 }
 
-func (sc *shardedCache) Add(k string, x interface{}, d time.Duration) error {
+func (sc *shardedCache[V]) Add(k string, x V, d time.Duration) error {
 	return sc.bucket(k).Add(k, x, d)
 }
 
-func (sc *shardedCache) Replace(k string, x interface{}, d time.Duration) error {
+func (sc *shardedCache[V]) Replace(k string, x V, d time.Duration) error {
 	return sc.bucket(k).Replace(k, x, d)
 }
 
-func (sc *shardedCache) Get(k string) (interface{}, bool) {
+func (sc *shardedCache[V]) Get(k string) (*V, bool) {
 	return sc.bucket(k).Get(k)
 }
 
-func (sc *shardedCache) Increment(k string, n int64) error {
+func (sc *shardedCache[V]) Increment(k string, n V) error {
-	return sc.bucket(k).Increment(k, n)
+	_, err := sc.bucket(k).Increment(k, n)
+	return err
 }
 
-func (sc *shardedCache) IncrementFloat(k string, n float64) error {
+func (sc *shardedCache[V]) Delete(k string) {
-	return sc.bucket(k).IncrementFloat(k, n)
-}
-
-func (sc *shardedCache) Decrement(k string, n int64) error {
-	return sc.bucket(k).Decrement(k, n)
-}
-
-func (sc *shardedCache) Delete(k string) {
 	sc.bucket(k).Delete(k)
 }
 
-func (sc *shardedCache) DeleteExpired() {
+func (sc *shardedCache[V]) DeleteExpired() {
 	for _, v := range sc.cs {
 		v.DeleteExpired()
 	}
@@ -109,26 +104,26 @@ func (sc *shardedCache) DeleteExpired() {
 // fields of the items should be checked. Note that explicit synchronization
 // is needed to use a cache and its corresponding Items() return values at
 // the same time, as the maps are shared.
-func (sc *shardedCache) Items() []map[string]Item {
+func (sc *shardedCache[V]) Items() []map[string]Item[V] {
-	res := make([]map[string]Item, len(sc.cs))
+	res := make([]map[string]Item[V], len(sc.cs))
 	for i, v := range sc.cs {
 		res[i] = v.Items()
 	}
 	return res
 }
 
-func (sc *shardedCache) Flush() {
+func (sc *shardedCache[V]) Flush() {
 	for _, v := range sc.cs {
 		v.Flush()
 	}
 }
 
-type shardedJanitor struct {
+type shardedJanitor[V constraints.Ordered] struct {
 	Interval time.Duration
 	stop     chan bool
 }
 
-func (j *shardedJanitor) Run(sc *shardedCache) {
+func (j *shardedJanitor[V]) Run(sc *shardedCache[V]) {
 	j.stop = make(chan bool)
 	tick := time.Tick(j.Interval)
 	for {
@@ -141,19 +136,19 @@ func (j *shardedJanitor) Run(sc *shardedCache) {
 	}
 }
 
-func stopShardedJanitor(sc *unexportedShardedCache) {
+func stopShardedJanitor[V constraints.Ordered](sc *unexportedShardedCache[V]) {
 	sc.janitor.stop <- true
 }
 
-func runShardedJanitor(sc *shardedCache, ci time.Duration) {
+func runShardedJanitor[V constraints.Ordered](sc *shardedCache[V], ci time.Duration) {
-	j := &shardedJanitor{
+	j := &shardedJanitor[V]{
 		Interval: ci,
 	}
 	sc.janitor = j
 	go j.Run(sc)
 }
 
-func newShardedCache(n int, de time.Duration) *shardedCache {
+func newShardedCache[V constraints.Ordered](n int, de time.Duration) *shardedCache[V] {
 	max := big.NewInt(0).SetUint64(uint64(math.MaxUint32))
 	rnd, err := rand.Int(rand.Reader, max)
 	var seed uint32
@@ -163,30 +158,34 @@ func newShardedCache(n int, de time.Duration) *shardedCache {
 	} else {
 		seed = uint32(rnd.Uint64())
 	}
-	sc := &shardedCache{
+	sc := &shardedCache[V]{
 		seed: seed,
 		m:    uint32(n),
-		cs:   make([]*cache, n),
+		cs:   make([]*orderedCache[string, V], n),
 	}
 	for i := 0; i < n; i++ {
-		c := &cache{
+		c := &orderedCache[string, V]{
-			defaultExpiration: de,
+			Cache: &Cache[string, V]{
-			items:             map[string]Item{},
+				cache: &cache[string, V]{
+					defaultExpiration: de,
+					items:             map[string]Item[V]{},
+				},
+			},
 		}
 		sc.cs[i] = c
 	}
 	return sc
 }
 
-func unexportedNewSharded(defaultExpiration, cleanupInterval time.Duration, shards int) *unexportedShardedCache {
+func unexportedNewSharded[V constraints.Ordered](defaultExpiration, cleanupInterval time.Duration, shards int) *unexportedShardedCache[V] {
 	if defaultExpiration == 0 {
 		defaultExpiration = -1
 	}
-	sc := newShardedCache(shards, defaultExpiration)
+	sc := newShardedCache[V](shards, defaultExpiration)
-	SC := &unexportedShardedCache{sc}
+	SC := &unexportedShardedCache[V]{sc}
 	if cleanupInterval > 0 {
 		runShardedJanitor(sc, cleanupInterval)
-		runtime.SetFinalizer(SC, stopShardedJanitor)
+		runtime.SetFinalizer(SC, stopShardedJanitor[V])
 	}
 	return SC
 }

sharded_test.go

@@ -27,7 +27,7 @@ var shardedKeys = []string{
 }
 
 func TestShardedCache(t *testing.T) {
-	tc := unexportedNewSharded(DefaultExpiration, 0, 13)
+	tc := unexportedNewSharded[string](DefaultExpiration, 0, 13)
 	for _, v := range shardedKeys {
 		tc.Set(v, "value", DefaultExpiration)
 	}
@@ -43,7 +43,7 @@ func BenchmarkShardedCacheGetNotExpiring(b *testing.B) {
 
 func benchmarkShardedCacheGet(b *testing.B, exp time.Duration) {
 	b.StopTimer()
-	tc := unexportedNewSharded(exp, 0, 10)
+	tc := unexportedNewSharded[string](exp, 0, 10)
 	tc.Set("foobarba", "zquux", DefaultExpiration)
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
@@ -62,7 +62,7 @@ func BenchmarkShardedCacheGetManyConcurrentNotExpiring(b *testing.B) {
 func benchmarkShardedCacheGetManyConcurrent(b *testing.B, exp time.Duration) {
 	b.StopTimer()
 	n := 10000
-	tsc := unexportedNewSharded(exp, 0, 20)
+	tsc := unexportedNewSharded[string](exp, 0, 20)
 	keys := make([]string, n)
 	for i := 0; i < n; i++ {
 		k := "foo" + strconv.Itoa(i)