add once for done

README.md

@@ -4,41 +4,42 @@
 
 ## introdction ##
 ---
-> DESC       : a asynchronous network I/O library in golang   
-  LICENCE    : Apache License 2.0   
-  AUTHOR     : https://github.com/sanbit   
-  MAINTAINER : Alex Stocks   
+> DESC       : a asynchronous network I/O library in golang
+  LICENCE    : Apache License 2.0
+  AUTHOR     : https://github.com/sanbit
+  MAINTAINER : Alex Stocks
   EMAIL      : alexstocks@foxmail.com
 
 ## develop history ##
 ---
 
 - 2016/08/24
-	> delete session.go:Session:wg(atomic.WaitGroup). Add session.go:Session:grNum instead to prevent from (Session)Close() block on session.go:Session:wg.Wait()   
-	> version: 0.2.05      
-    
+	> delete session.go:Session:wg(atomic.WaitGroup). Add session.go:Session:grNum instead to prevent from (Session)Close() block on session.go:Session:wg.Wait()
+	> add once for session.go:Session:done(chan struct{})
+	> version: 0.2.05
+
 - 2016/08/23
-	> do not consider empty package as a error in (Session)handlePackage   
-	> version: 0.2.04   
-    
+	> do not consider empty package as a error in (Session)handlePackage
+	> version: 0.2.04
+
 - 2016/08/22
-	> rename (Session)OnIdle to (Session)OnCron   
-	> rewrite server.go: add Server{done, wg}   
-	> add utils.go   
-	> version: 0.2.03   
+	> rename (Session)OnIdle to (Session)OnCron
+	> rewrite server.go: add Server{done, wg}
+	> add utils.go
+	> version: 0.2.03
 
 - 2016/08/21
-	> add name for Session   
-	> add OnError for Codec   
+	> add name for Session
+	> add OnError for Codec
 
 - 2016/08/18
-	> delete last clause of handleRead   
-	> add reqQ handle case in last clause of handleLoop   
-	> add conditon check in (*Session)RunEventLoop()   
-	> version: 0.2.02   
+	> delete last clause of handleRead
+	> add reqQ handle case in last clause of handleLoop
+	> add conditon check in (*Session)RunEventLoop()
+	> version: 0.2.02
 
 - 2016/08/16
-	> rename all structs   
-	> add getty connection   
-	> rewrite (Session)handleRead & (Session)handleEventLoop   
-	> version: 0.2.01   
+	> rename all structs
+	> add getty connection
+	> rewrite (Session)handleRead & (Session)handleEventLoop
+	> version: 0.2.01

session.go

@@ -84,6 +84,7 @@ type Session struct {
 	*gettyConn
 	pkgHandler ReadWriter
 	listener   EventListener
+	once       sync.Once
 	done       chan struct{}
 	readerDone chan struct{} // end reader
 
@@ -98,7 +99,7 @@ type Session struct {
 	attrs map[string]interface{}
 	// goroutines sync
 	grNum int32
-	lock sync.RWMutex
+	lock  sync.RWMutex
 }
 
 func NewSession(conn net.Conn) *Session {
@@ -239,7 +240,8 @@ func (this *Session) stop() {
 	case <-this.done:
 		return
 	default:
-		close(this.done)
+		// defeat "panic: close of closed channel"
+		this.once.Do(func() { close(this.done) })
 	}
 }