[Fix] Check if can register a context

websocket-sharp/Net/HttpConnection.cs

@@ -303,7 +303,12 @@ namespace WebSocketSharp.Net
           }
 
           conn._contextBound = true;
-          lsnr.RegisterContext (conn._context);
+          if (!lsnr.RegisterContext (conn._context)) {
+            conn._contextBound = false;
+            conn.close ();
+
+            return;
+          }
 
           return;
         }

websocket-sharp/Net/HttpListener.cs

@@ -581,12 +581,17 @@ namespace WebSocketSharp.Net
         throw new ObjectDisposedException (GetType ().ToString ());
     }
 
-    internal void RegisterContext (HttpListenerContext context)
+    internal bool RegisterContext (HttpListenerContext context)
     {
-      lock (_ctxRegistrySync)
-        _ctxRegistry[context] = context;
+      if (!_listening)
+        return false;
 
       HttpListenerAsyncResult ares = null;
+      lock (_ctxRegistrySync) {
+        if (!_listening)
+          return false;
+
+        _ctxRegistry[context] = context;
         lock (_waitQueueSync) {
           if (_waitQueue.Count == 0) {
             lock (_ctxQueueSync)
@@ -597,9 +602,12 @@ namespace WebSocketSharp.Net
             _waitQueue.RemoveAt (0);
           }
         }
+      }
 
       if (ares != null)
         ares.Complete (context);
+
+      return true;
     }
 
     internal void RemoveConnection (HttpConnection connection)