*: fix data race in the cache (#294)

* *: fix data race in the cache

Signed-off-by: Weizhen Wang <[email protected]>

* fix

cache.go

@@ -26,6 +26,7 @@ import (
 	"unsafe"
 
 	"github.com/dgraph-io/ristretto/z"
+	"go.uber.org/atomic"
 )
 
 var (
@@ -64,7 +65,7 @@ type Cache struct {
 	// stop is used to stop the processItems goroutine.
 	stop chan struct{}
 	// indicates whether cache is closed.
-	isClosed bool
+	isClosed atomic.Bool
 	// cost calculates cost from a value.
 	cost func(value interface{}) int64
 	// ignoreInternalCost dictates whether to ignore the cost of internally storing
@@ -214,7 +215,7 @@ func NewCache(config *Config) (*Cache, error) {
 }
 
 func (c *Cache) Wait() {
-	if c == nil || c.isClosed {
+	if c == nil || c.isClosed.Load() {
 		return
 	}
 	wg := &sync.WaitGroup{}
@@ -227,7 +228,7 @@ func (c *Cache) Wait() {
 // value was found or not. The value can be nil and the boolean can be true at
 // the same time.
 func (c *Cache) Get(key interface{}) (interface{}, bool) {
-	if c == nil || c.isClosed || key == nil {
+	if c == nil || c.isClosed.Load() || key == nil {
 		return nil, false
 	}
 	keyHash, conflictHash := c.keyToHash(key)
@@ -270,7 +271,7 @@ func (c *Cache) SetIfPresent(key, value interface{}, cost int64) bool {
 
 func (c *Cache) setInternal(key, value interface{},
 	cost int64, ttl time.Duration, onlyUpdate bool) bool {
-	if c == nil || c.isClosed || key == nil {
+	if c == nil || c.isClosed.Load() || key == nil {
 		return false
 	}
 
@@ -326,7 +327,7 @@ func (c *Cache) setInternal(key, value interface{},
 
 // Del deletes the key-value item from the cache if it exists.
 func (c *Cache) Del(key interface{}) {
-	if c == nil || c.isClosed || key == nil {
+	if c == nil || c.isClosed.Load() || key == nil {
 		return
 	}
 	keyHash, conflictHash := c.keyToHash(key)
@@ -373,7 +374,7 @@ func (c *Cache) GetTTL(key interface{}) (time.Duration, bool) {
 
 // Close stops all goroutines and closes all channels.
 func (c *Cache) Close() {
-	if c == nil || c.isClosed {
+	if c == nil || c.isClosed.Load() {
 		return
 	}
 	c.Clear()
@@ -383,14 +384,14 @@ func (c *Cache) Close() {
 	close(c.stop)
 	close(c.setBuf)
 	c.policy.Close()
-	c.isClosed = true
+	c.isClosed.Store(true)
 }
 
 // Clear empties the hashmap and zeroes all policy counters. Note that this is
 // not an atomic operation (but that shouldn't be a problem as it's assumed that
 // Set/Get calls won't be occurring until after this).
 func (c *Cache) Clear() {
-	if c == nil || c.isClosed {
+	if c == nil || c.isClosed.Load() {
 		return
 	}
 	// Block until processItems goroutine is returned.

go.mod

@@ -4,11 +4,11 @@ go 1.12
 
 require (
 	github.com/cespare/xxhash/v2 v2.1.1
-	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/dgryski/go-farm v0.0.0-20190423205320-6a90982ecee2
 	github.com/dustin/go-humanize v1.0.0
 	github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b
 	github.com/pkg/errors v0.9.1
 	github.com/stretchr/testify v1.4.0
+	go.uber.org/atomic v1.9.0
 	golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f
 )

go.sum

@@ -14,8 +14,11 @@ github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+go.uber.org/atomic v1.9.0 h1:ECmE8Bn/WFTYwEW/bpKD3M8VtR/zQVbavAoalC1PYyE=
+go.uber.org/atomic v1.9.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f h1:+Nyd8tzPX9R7BWHguqsrbFdRx3WQ/1ib8I44HXV5yTA=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=