add cache module

cache/memcache.go

@@ -0,0 +1,102 @@
+package cache
+
+import (
+	"code.google.com/p/vitess/go/memcache"
+	"encoding/json"
+	"errors"
+)
+
+type MemcacheCache struct {
+	c        *memcache.Connection
+	conninfo string
+}
+
+func NewMemCache() *MemcacheCache {
+	return &MemcacheCache{}
+}
+
+func (rc *MemcacheCache) Get(key string) interface{} {
+	if rc.c == nil {
+		rc.c = rc.connectInit()
+	}
+	v, _, err := rc.c.Get(key)
+	if err != nil {
+		return nil
+	}
+	var contain interface{}
+	contain = v
+	return contain
+}
+
+func (rc *MemcacheCache) Put(key string, val interface{}, timeout int) error {
+	if rc.c == nil {
+		rc.c = rc.connectInit()
+	}
+	v, ok := val.(string)
+	if !ok {
+		return errors.New("val must string")
+	}
+	stored, err := rc.c.Set(key, 0, uint64(timeout), []byte(v))
+	if err == nil && stored == false {
+		return errors.New("stored fail")
+	}
+	return err
+}
+
+func (rc *MemcacheCache) Delete(key string) error {
+	if rc.c == nil {
+		rc.c = rc.connectInit()
+	}
+	_, err := rc.c.Delete(key)
+	return err
+}
+
+func (rc *MemcacheCache) IsExist(key string) bool {
+	if rc.c == nil {
+		rc.c = rc.connectInit()
+	}
+	v, _, err := rc.c.Get(key)
+	if err != nil {
+		return false
+	}
+	if len(v) == 0 {
+		return false
+	} else {
+		return true
+	}
+	return true
+}
+
+func (rc *MemcacheCache) ClearAll() error {
+	if rc.c == nil {
+		rc.c = rc.connectInit()
+	}
+	err := rc.c.FlushAll()
+	return err
+}
+
+func (rc *MemcacheCache) StartAndGC(config string) error {
+	var cf map[string]string
+	json.Unmarshal([]byte(config), &cf)
+	if _, ok := cf["conn"]; !ok {
+		return errors.New("config has no conn key")
+	}
+	rc.conninfo = cf["conn"]
+	rc.c = rc.connectInit()
+	if rc.c == nil {
+		return errors.New("dial tcp conn error")
+	}
+	return nil
+}
+
+func (rc *MemcacheCache) connectInit() *memcache.Connection {
+	c, err := memcache.Connect(rc.conninfo)
+	if err != nil {
+		return nil
+	}
+	return c
+}
+
+func init() {
+	Register("memcache", NewMemCache())
+}