feat: 封装lru、byte数据、缓存组&添加测试用例

byte_value.go

@@ -0,0 +1,25 @@
+package thqcache
+
+//ByteValue 数据格式封装
+type ByteValue struct {
+	b []byte
+}
+
+func (v ByteValue) Len() int {
+	return len(v.b)
+}
+
+func (v ByteValue) ByteSlice() []byte {
+	return cloneBytes(v.b)
+}
+
+func (v ByteValue) String() string {
+	return string(v.b)
+}
+
+//cloneBytes 深拷贝防止修改b
+func cloneBytes(b []byte) []byte {
+	c := make([]byte, len(b))
+	copy(c, b)
+	return c
+}

cache.go

@@ -0,0 +1,35 @@
+package thqcache
+
+import (
+	"github.com/ithaiq/thqcache/lru"
+	"sync"
+)
+
+//cache lru Cache封装 + 锁并发控制
+type cache struct {
+	lru      *lru.Cache
+	mu       sync.Mutex
+	maxBytes int64
+}
+
+func (this *cache) add(key string, value ByteValue) {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+	//懒加载 性能考虑
+	if this.lru == nil {
+		this.lru = lru.NewCache(this.maxBytes, nil)
+	}
+	this.lru.Add(key, value)
+}
+
+func (this *cache) get(key string) (value ByteValue, ok bool) {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+	if this.lru == nil {
+		return
+	}
+	if v, ok := this.lru.Get(key); ok {
+		return v.(ByteValue), true
+	}
+	return
+}

thqcache.go

@@ -0,0 +1,76 @@
+package thqcache
+
+import (
+	"fmt"
+	"sync"
+)
+
+type Getter interface {
+	Get(key string) ([]byte, error)
+}
+
+//接口型函数
+//方便使用者在调用时既能够传入函数作为参数，也能够传入实现了该接口的结构体作为参数。
+
+type GetterFunc func(key string) ([]byte, error)
+
+func (f GetterFunc) Get(key string) ([]byte, error) {
+	return f(key)
+}
+
+type Group struct {
+	name   string
+	getter Getter
+	c      cache
+}
+
+var (
+	mu     sync.RWMutex
+	groups = make(map[string]*Group)
+)
+
+func NewGroup(name string, maxBytes int64, getter Getter) *Group {
+	if getter == nil {
+		panic("nil Getter")
+	}
+	mu.Lock()
+	defer mu.Unlock()
+	g := &Group{
+		name:   name,
+		getter: getter,
+		c:      cache{maxBytes: maxBytes},
+	}
+	groups[name] = g
+	return g
+}
+
+func GetGroup(name string) *Group {
+	mu.RLock()
+	defer mu.RUnlock()
+	return groups[name]
+}
+
+func (this *Group) Add(key string, value ByteValue) {
+	this.c.add(key, value)
+}
+
+func (this *Group) Get(key string) (ByteValue, error) {
+	if key == "" {
+		return ByteValue{}, fmt.Errorf("key is empty")
+	}
+	if v, ok := this.c.get(key); ok {
+		return v, nil
+	}
+	return this.loadLocal(key)
+}
+
+//loadLocal 加载本地数据到缓存
+func (this *Group) loadLocal(key string) (ByteValue, error) {
+	bytes, err := this.getter.Get(key)
+	if err != nil {
+		return ByteValue{}, err
+	}
+	value := ByteValue{b: cloneBytes(bytes)}
+	this.Add(key, value)
+	return value, nil
+}

thqcache_test.go

@@ -0,0 +1,40 @@
+package thqcache
+
+import (
+	"fmt"
+	"github.com/stretchr/testify/require"
+	"testing"
+)
+
+var db = map[string]string{
+	"thq1": "1",
+	"thq2": "2",
+	"thq3": "3",
+}
+
+func TestGroup_Get(t *testing.T) {
+	loadCount := make(map[string]int, len(db))
+	getter := func(key string) ([]byte, error) {
+		if v, ok := db[key]; ok {
+			if _, ok := loadCount[key]; !ok {
+				loadCount[key] = 0
+			}
+			loadCount[key]++
+			return []byte(v), nil
+		}
+		return nil, fmt.Errorf("%s not exist", key)
+	}
+
+	g := NewGroup("test", 2<<10, GetterFunc(getter))
+
+	for k, v := range db {
+		value, err := g.Get(k)
+		require.NoError(t, err)
+		require.Equal(t, value.String(), v)
+		_, err = g.Get(k)
+		require.NoError(t, err)
+		require.True(t, loadCount[k] == 1)
+	}
+	_, err := g.Get("no")
+	require.True(t, err != nil)
+}