refactor: cache

bucket.go

@@ -1,56 +1,49 @@
 package roc
 
 import (
-	"container/list"
 	"sync"
 	"time"
 )
 
+// Bucket is a piece of cache.
 type Bucket struct {
-	guard sync.Mutex
-	objs  *list.List
-	coll  map[string]*list.Element
+	coll sync.Map
 }
 
+// NewBucket returns a bucket.
 func NewBucket() (*Bucket, error) {
 	b := new(Bucket)
 	return b, nil
 }
 
+// Get returns a corresponding value.
 func (b *Bucket) Get(key string) (interface{}, error) {
-	b.guard.Lock()
-	defer b.guard.Unlock()
-	element, hit := b.coll[key]
+	value, hit := b.coll.Load(key)
 	if !hit {
 		return nil, ErrMiss
 	}
-	u, ok := element.Value.(*Unit)
+	u, ok := value.(*Unit)
 	if !ok {
 		return nil, ErrMiss
 	}
-
 	if u.Expire() {
 		return nil, ErrMiss
 	}
-	b.objs.MoveToFront(element)
 	return u.Data, nil
 }
 
+// Set sets a value for a key.
 func (b *Bucket) Set(key string, data interface{}, d time.Duration) error {
-	b.guard.Lock()
-	defer b.guard.Unlock()
-	element, hit := b.coll[key]
+	value, hit := b.coll.Load(key)
 	if !hit {
 		unit := new(Unit)
 		unit.Key = key
 		unit.Data = data
 		unit.ExpirationTime = time.Now().UTC().Add(d)
-		e := b.objs.PushFront(unit)
-		b.coll[key] = e
+		b.coll.Store(key, unit)
 		return nil
 	}
-	b.objs.MoveToFront(element)
-	unit, ok := element.Value.(*Unit)
+	unit, ok := value.(*Unit)
 	if !ok {
 		return nil
 	}
@@ -59,29 +52,22 @@ func (b *Bucket) Set(key string, data interface{}, d time.Duration) error {
 	return nil
 }
 
+// Del deletes a key.
 func (b *Bucket) Del(key string) {
-	b.guard.Lock()
-	defer b.guard.Unlock()
-	element, hit := b.coll[key]
-	if !hit {
-		return
-	}
-	b.del(key, element)
-}
-
-func (b *Bucket) del(key string, e *list.Element) {
-	b.objs.Remove(e)
-	delete(b.coll, key)
+	b.coll.Delete(key)
 }
 
 func (b *Bucket) gc() {
-	b.guard.Lock()
-	defer b.guard.Unlock()
-
-	for e := b.objs.Front(); e != nil; e = e.Next() {
-		unit, ok := e.Value.(*Unit)
-		if ok && unit.Expire() {
-			b.del(unit.Key, e)
+	b.coll.Range(func(key, value interface{}) (keep bool) {
+		keep = true
+		unit, ok := value.(*Unit)
+		if !ok {
+			return
 		}
-	}
+		if !unit.Expire() {
+			return
+		}
+		b.Del(key.(string))
+		return
+	})
 }

cache.go

@@ -1,13 +1,13 @@
 package roc
 
 import (
-	"container/list"
 	"context"
 	"time"
 
 	"github.com/xiaojiaoyu100/curlew"
 )
 
+// Cache is a store.
 type Cache struct {
 	GCInterval time.Duration
 	BucketNum  int
@@ -16,28 +16,24 @@ type Cache struct {
 	close      chan struct{}
 }
 
+// New returns a new cache.
 func New(setters ...Setter) (*Cache, error) {
 	c := new(Cache)
-	c.GCInterval = 60 * time.Second
-	c.BucketNum = 16
+	c.GCInterval = 120 * time.Second
+	c.BucketNum = 1024
 
 	for _, setter := range setters {
 		if err := setter(c); err != nil {
 			return nil, err
 		}
 	}
 
-	if !isPowerOfTwo(c.BucketNum) {
-		return nil, ErrorBucketNum
-	}
 	c.buckets = make([]*Bucket, 0, c.BucketNum)
 	for idx := 0; idx < c.BucketNum; idx++ {
 		bucket, err := NewBucket()
 		if err != nil {
 			return nil, err
 		}
-		bucket.coll = make(map[string]*list.Element)
-		bucket.objs = list.New()
 		c.buckets = append(c.buckets, bucket)
 	}
 
@@ -78,6 +74,7 @@ func (c *Cache) gc() {
 	}()
 }
 
+// Get returns a value.
 func (c *Cache) Get(key string) (interface{}, error) {
 	idx, err := c.hashIndex(key)
 	if err != nil {
@@ -86,6 +83,7 @@ func (c *Cache) Get(key string) (interface{}, error) {
 	return c.buckets[idx].Get(key)
 }
 
+// Set sets a value.
 func (c *Cache) Set(key string, value interface{}, duration time.Duration) error {
 	idx, err := c.hashIndex(key)
 	if err != nil {
@@ -94,6 +92,7 @@ func (c *Cache) Set(key string, value interface{}, duration time.Duration) error
 	return c.buckets[idx].Set(key, value, duration)
 }
 
+// Del deletes a key.
 func (c *Cache) Del(key string) error {
 	idx, err := c.hashIndex(key)
 	if err != nil {

cache_test.go

@@ -0,0 +1,18 @@
+package roc
+
+import (
+	"testing"
+	"time"
+)
+
+func TestCache_Set(t *testing.T) {
+	c, err := New()
+	if err != nil {
+		t.Fatalf("new cache failed")
+	}
+	err = c.Set("one", "two", time.Second)
+	if err != nil {
+		t.Fatalf("set failed")
+	}
+	t.Log(c.Get("one"))
+}

error.go

@@ -1,12 +1,14 @@
 package roc
 
+// Error implements an error interface.
 type Error string
 
+// Error returns a error string.
 func (e Error) Error() string {
 	return string(e)
 }
 
 const (
-	ErrMiss        = Error("cache miss")
-	ErrorBucketNum = Error("bucket num must be the power of two")
+	// ErrMiss represents a cache miss.
+	ErrMiss = Error("cache miss")
 )

go.mod

@@ -1,6 +1,6 @@
 module github.com/xiaojiaoyu100/roc
 
-go 1.12
+go 1.14
 
 require (
 	github.com/xiaojiaoyu100/curlew v0.2.1

go.sum

@@ -1,18 +1,47 @@
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hash.go

@@ -8,5 +8,5 @@ func (c *Cache) hashIndex(key string) (int, error) {
 	if err != nil {
 		return 0, err
 	}
-	return int(hash.Sum64() & uint64(c.BucketNum - 1)), nil
+	return int(hash.Sum64() & uint64(c.BucketNum-1)), nil
 }

setter.go

@@ -4,12 +4,9 @@ import (
 	"time"
 )
 
+// Setter configures a cache.
 type Setter func(c *Cache) error
 
-func isPowerOfTwo(num int) bool {
-	return (num != 0) && ((num & (num - 1)) == 0)
-}
-
 // WithBucketNum set the number of buckets
 func WithBucketNum(num int) Setter {
 	return func(c *Cache) error {