From a03fa0fb736ece41b6be2c30b1c3f92d88e07414 Mon Sep 17 00:00:00 2001
From: astaxie <xiemengjun@gmail.com>
Date: Mon, 4 Jan 2016 10:50:04 +0800
Subject: [PATCH] improve cache modules. support mulit instances

---
 cache/cache.go             | 11 +++++++----
 cache/file.go              | 10 +++++-----
 cache/memcache/memcache.go |  4 ++--
 cache/memory.go            |  4 ++--
 cache/redis/redis.go       |  4 ++--
 5 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/cache/cache.go b/cache/cache.go
index 6413e210..c9904444 100644
--- a/cache/cache.go
+++ b/cache/cache.go
@@ -37,7 +37,7 @@ import (
 
 // Cache interface contains all behaviors for cache adapter.
 // usage:
-//	cache.Register("file",cache.NewFileCache()) // this operation is run in init method of file.go.
+//	cache.Register("file",cache.NewFileCache) // this operation is run in init method of file.go.
 //	c,err := cache.NewCache("file","{....}")
 //	c.Put("key",value,3600)
 //	v := c.Get("key")
@@ -66,12 +66,14 @@ type Cache interface {
 	StartAndGC(config string) error
 }
 
-var adapters = make(map[string]Cache)
+type CacheInstance func() Cache
+
+var adapters = make(map[string]CacheInstance)
 
 // Register makes a cache adapter available by the adapter name.
 // If Register is called twice with the same name or if driver is nil,
 // it panics.
-func Register(name string, adapter Cache) {
+func Register(name string, adapter CacheInstance) {
 	if adapter == nil {
 		panic("cache: Register adapter is nil")
 	}
@@ -85,11 +87,12 @@ func Register(name string, adapter Cache) {
 // config need to be correct JSON as string: {"interval":360}.
 // it will start gc automatically.
 func NewCache(adapterName, config string) (adapter Cache, err error) {
-	adapter, ok := adapters[adapterName]
+	instanceFunc, ok := adapters[adapterName]
 	if !ok {
 		err = fmt.Errorf("cache: unknown adapter name %q (forgot to import?)", adapterName)
 		return
 	}
+	adapter = instanceFunc()
 	err = adapter.StartAndGC(config)
 	if err != nil {
 		adapter = nil
diff --git a/cache/file.go b/cache/file.go
index 9233a852..2d77b567 100644
--- a/cache/file.go
+++ b/cache/file.go
@@ -29,10 +29,6 @@ import (
 	"time"
 )
 
-func init() {
-	Register("file", NewFileCache())
-}
-
 // FileCacheItem is basic unit of file cache adapter.
 // it contains data and expire time.
 type FileCacheItem struct {
@@ -59,7 +55,7 @@ type FileCache struct {
 
 // NewFileCache Create new file cache with no config.
 // the level and expiry need set in method StartAndGC as config string.
-func NewFileCache() *FileCache {
+func NewFileCache() Cache {
 	//    return &FileCache{CachePath:FileCachePath, FileSuffix:FileCacheFileSuffix}
 	return &FileCache{}
 }
@@ -272,3 +268,7 @@ func GobDecode(data []byte, to *FileCacheItem) error {
 	dec := gob.NewDecoder(buf)
 	return dec.Decode(&to)
 }
+
+func init() {
+	Register("file", NewFileCache)
+}
diff --git a/cache/memcache/memcache.go b/cache/memcache/memcache.go
index 643fb130..272124da 100644
--- a/cache/memcache/memcache.go
+++ b/cache/memcache/memcache.go
@@ -46,7 +46,7 @@ type Cache struct {
 }
 
 // NewMemCache create new memcache adapter.
-func NewMemCache() *Cache {
+func NewMemCache() cache.Cache {
 	return &Cache{}
 }
 
@@ -184,5 +184,5 @@ func (rc *Cache) connectInit() error {
 }
 
 func init() {
-	cache.Register("memcache", NewMemCache())
+	cache.Register("memcache", NewMemCache)
 }
diff --git a/cache/memory.go b/cache/memory.go
index ce1afa5f..5cc0ab52 100644
--- a/cache/memory.go
+++ b/cache/memory.go
@@ -44,7 +44,7 @@ type MemoryCache struct {
 }
 
 // NewMemoryCache returns a new MemoryCache.
-func NewMemoryCache() *MemoryCache {
+func NewMemoryCache() Cache {
 	cache := MemoryCache{items: make(map[string]*MemoryItem)}
 	return &cache
 }
@@ -234,5 +234,5 @@ func (bc *MemoryCache) itemExpired(name string) bool {
 }
 
 func init() {
-	Register("memory", NewMemoryCache())
+	Register("memory", NewMemoryCache)
 }
diff --git a/cache/redis/redis.go b/cache/redis/redis.go
index ed12cf26..60c1702a 100644
--- a/cache/redis/redis.go
+++ b/cache/redis/redis.go
@@ -55,7 +55,7 @@ type Cache struct {
 }
 
 // NewRedisCache create new redis cache with default collection name.
-func NewRedisCache() *Cache {
+func NewRedisCache() cache.Cache {
 	return &Cache{key: DefaultKey}
 }
 
@@ -236,5 +236,5 @@ func (rc *Cache) connectInit() {
 }
 
 func init() {
-	cache.Register("redis", NewRedisCache())
+	cache.Register("redis", NewRedisCache)
 }