fix the thread stop bug, must wait when not joinable.

@@ -539,8 +539,6 @@ void SrsServer::destroy()
     }
     
     srs_freep(signal_manager);
-    
-    srs_freep(handler);
 }
 
 void SrsServer::dispose()

@@ -293,10 +293,14 @@ private:
     virtual void dispose();
 // server startup workflow, @see run_master()
 public:
+    /**
+     * initialize server with callback handler.
+     * @remark user must free the cycle handler.
+     */
     virtual int initialize(ISrsServerCycle* cycle_handler);
+    virtual int initialize_st();
     virtual int initialize_signal();
     virtual int acquire_pid_file();
-    virtual int initialize_st();
     virtual int listen();
     virtual int register_signal();
     virtual int http_handle();

@@ -129,19 +129,20 @@ namespace internal {
                 if (ret) {
                     srs_warn("core: ignore join thread failed.");
                 }
+            }
+            
+            // wait the thread actually terminated.
+            // sometimes the thread join return -1, for example,
+            // when thread use st_recvfrom, the thread join return -1.
+            // so here, we use a variable to ensure the thread stopped.
+            // @remark even the thread not joinable, we must ensure the thread stopped when stop.
+            while (!really_terminated) {
+                st_usleep(10 * 1000);
                 
-                // wait the thread actually terminated.
-                // sometimes the thread join return -1, for example,
-                // when thread use st_recvfrom, the thread join return -1.
-                // so here, we use a variable to ensure the thread stopped.
-                while (!really_terminated) {
-                    st_usleep(10 * 1000);
-                    
-                    if (really_terminated) {
-                        break;
-                    }
-                    srs_warn("core: wait thread to actually terminated");
+                if (really_terminated) {
+                    break;
                 }
+                srs_warn("core: wait thread to actually terminated");
             }
             
             tid = NULL;