AtomicInt: wrap sync/atomic.Int64 w/ go 1.19

Leverage sync/atomic.Int64 with go 1.19 (and keep the same code for
earlier versions)

Use build tags as appropriate.

atomic_int.go

@@ -0,0 +1,42 @@
+//go:build !go1.19
+
+/*
+Copyright 2012 Google Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package galaxycache
+
+import (
+	"strconv"
+	"sync/atomic"
+)
+
+// An AtomicInt is an int64 to be accessed atomically.
+// It thinly wraps atomic.Int64 with go1.19+
+type AtomicInt int64
+
+// Add atomically adds n to i.
+func (i *AtomicInt) Add(n int64) {
+	atomic.AddInt64((*int64)(i), n)
+}
+
+// Get atomically gets the value of i.
+func (i *AtomicInt) Get() int64 {
+	return atomic.LoadInt64((*int64)(i))
+}
+
+func (i *AtomicInt) String() string {
+	return strconv.FormatInt(i.Get(), 10)
+}

atomic_int_go1.19.go

@@ -0,0 +1,44 @@
+//go:build go1.19
+
+/*
+Copyright 2022 Vimeo Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package galaxycache
+
+import (
+	"strconv"
+	"sync/atomic"
+)
+
+// An AtomicInt is an int64 to be accessed atomically.
+// It thinly wraps atomic.Int64 with go1.19+
+type AtomicInt struct {
+	v atomic.Int64
+}
+
+// Add atomically adds n to i.
+func (i *AtomicInt) Add(n int64) {
+	i.v.Add(n)
+}
+
+// Get atomically gets the value of i.
+func (i *AtomicInt) Get() int64 {
+	return i.v.Load()
+}
+
+func (i *AtomicInt) String() string {
+	return strconv.FormatInt(i.Get(), 10)
+}

galaxycache.go

@@ -28,9 +28,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"strconv"
 	"sync"
-	"sync/atomic"
 	"time"
 	"unsafe"
 
@@ -765,23 +763,6 @@ func (c *cache) itemsLocked() int64 {
 	return int64(c.lru.Len())
 }
 
-// An AtomicInt is an int64 to be accessed atomically.
-type AtomicInt int64
-
-// Add atomically adds n to i.
-func (i *AtomicInt) Add(n int64) {
-	atomic.AddInt64((*int64)(i), n)
-}
-
-// Get atomically gets the value of i.
-func (i *AtomicInt) Get() int64 {
-	return atomic.LoadInt64((*int64)(i))
-}
-
-func (i *AtomicInt) String() string {
-	return strconv.FormatInt(i.Get(), 10)
-}
-
 // CacheStats are returned by stats accessors on Galaxy.
 type CacheStats struct {
 	Bytes     int64