WiFi: Properly guard socket.close()

Author: facchinm

libraries/WiFi/src/WiFiClient.cpp

@@ -118,9 +118,11 @@ void arduino::WiFiClient::flush() {
 }
 
 void arduino::WiFiClient::stop() {
-	sock->close();
-	delete sock;
-	sock = NULL;
+	if (sock != NULL) {
+		sock->close();
+		//delete[] sock;
+		sock = NULL;
+	}
 }
 
 uint8_t arduino::WiFiClient::connected() {

libraries/WiFi/src/WiFiClient.h

@@ -33,6 +33,9 @@ class WiFiClient : public arduino::Client {
 
 public:
   WiFiClient();
+  ~WiFiClient() {
+    stop();
+  }
 
   uint8_t status();
   int connect(IPAddress ip, uint16_t port);

libraries/WiFi/src/WiFiServer.cpp

@@ -34,7 +34,12 @@ size_t arduino::WiFiServer::write(const uint8_t *buf, size_t size) {
 
 arduino::WiFiClient arduino::WiFiServer::available(uint8_t* status) {
 	WiFiClient ret;
-	TCPSocket* client = sock->accept();
-	ret.setSocket(client);
+	nsapi_error_t error;
+	TCPSocket* client = sock->accept(&error);
+	if (error != 0) {
+		ret.setSocket(NULL);
+	} else {
+		ret.setSocket(client);
+	}
 	return ret;
 }