fix: ensure the payload format is valid

This commit should prevent some NPE issues encountered after the
parsing of the packet.

Related:

- https://github.com/socketio/socket.io-client-java/issues/642
- https://github.com/socketio/socket.io-client-java/issues/609
- https://github.com/socketio/socket.io-client-java/issues/505

src/main/java/io/socket/client/Manager.java

@@ -326,10 +326,14 @@ public class Manager extends Emitter {
             @Override
             public void call(Object... objects) {
                 Object data = objects[0];
-                if (data instanceof String) {
-                    Manager.this.ondata((String)data);
-                } else if (data instanceof byte[]) {
-                    Manager.this.ondata((byte[])data);
+                try {
+                    if (data instanceof String) {
+                        Manager.this.decoder.add((String) data);
+                    } else if (data instanceof byte[]) {
+                        Manager.this.decoder.add((byte[]) data);
+                    }
+                } catch (DecodingException e) {
+                    logger.fine("error while decoding the packet: " + e.getMessage());
                 }
             }
         }));
@@ -353,22 +357,6 @@ public class Manager extends Emitter {
         });
     }
 
-    private void ondata(String data) {
-        try {
-            this.decoder.add(data);
-        } catch (DecodingException e) {
-            this.onerror(e);
-        }
-    }
-
-    private void ondata(byte[] data) {
-        try {
-            this.decoder.add(data);
-        } catch (DecodingException e) {
-            this.onerror(e);
-        }
-    }
-
     private void ondecoded(Packet packet) {
         this.emit(EVENT_PACKET, packet);
     }

src/main/java/io/socket/parser/IOParser.java

@@ -1,7 +1,9 @@
 package io.socket.parser;
 
 import io.socket.hasbinary.HasBinary;
+import org.json.JSONArray;
 import org.json.JSONException;
+import org.json.JSONObject;
 import org.json.JSONTokener;
 
 import java.util.ArrayList;
@@ -183,6 +185,9 @@ final public class IOParser implements Parser {
                     logger.log(Level.WARNING, "An error occured while retrieving data from JSONTokener", e);
                     throw new DecodingException("invalid payload");
                 }
+                if (!isPayloadValid(p.type, p.data)) {
+                    throw new DecodingException("invalid payload");
+                }
             }
 
             if (logger.isLoggable(Level.FINE)) {
@@ -191,6 +196,26 @@ final public class IOParser implements Parser {
             return p;
         }
 
+        private static boolean isPayloadValid(int type, Object payload) {
+            switch (type) {
+                case Parser.CONNECT:
+                case Parser.CONNECT_ERROR:
+                    return payload instanceof JSONObject;
+                case Parser.DISCONNECT:
+                    return payload == null;
+                case Parser.EVENT:
+                case Parser.BINARY_EVENT:
+                    return payload instanceof JSONArray
+                            && ((JSONArray) payload).length() > 0
+                            && !((JSONArray) payload).isNull(0);
+                case Parser.ACK:
+                case Parser.BINARY_ACK:
+                    return payload instanceof JSONArray;
+                default:
+                    return false;
+            }
+        }
+
         @Override
         public void destroy() {
             if (this.reconstructor != null) {