[Modify] Throw exceptions

websocket-sharp/WebSocket.cs

@@ -2991,14 +2991,37 @@ namespace WebSocketSharp
     /// </param>
     public void CloseAsync (CloseStatusCode code, string reason)
     {
-      string msg;
-      if (!CheckParametersForClose (code, reason, _client, out msg)) {
-        _logger.Error (msg);
-        error ("An error has occurred in closing the connection.", null);
+      if (_client && code == CloseStatusCode.ServerError) {
+        var msg = "ServerError cannot be used.";
+        throw new ArgumentException (msg, "code");
+      }
 
+      if (!_client && code == CloseStatusCode.MandatoryExtension) {
+        var msg = "MandatoryExtension cannot be used.";
+        throw new ArgumentException (msg, "code");
+      }
+
+      if (reason.IsNullOrEmpty ()) {
+        closeAsync ((ushort) code, String.Empty);
         return;
       }
 
+      if (code == CloseStatusCode.NoStatus) {
+        var msg = "NoStatus cannot be used.";
+        throw new ArgumentException (msg, "code");
+      }
+
+      byte[] bytes;
+      if (!reason.TryGetUTF8EncodedBytes (out bytes)) {
+        var msg = "It could not be UTF-8-encoded.";
+        throw new ArgumentException (msg, "reason");
+      }
+
+      if (bytes.Length > 123) {
+        var msg = "Its size is greater than 123 bytes.";
+        throw new ArgumentOutOfRangeException ("reason", msg);
+      }
+
       closeAsync ((ushort) code, reason);
     }