fix: SyncClient memory leak, handling connect() errors (#31)

* fix: SyncClient memory leak, handling connect() errors

SyncClient didn't delete the _client object when an error occurred in
connect(), before _onConnect(). Also, _client was not properly deleted
in such case.

* fix: SyncClient memory leak, handling connect() errors ...also for the connect(ip)

Author: michalfapso

src/SyncClient.cpp

@@ -62,6 +62,7 @@ int SyncClient::connect(IPAddress ip, uint16_t port){
     return 0;
   _client = new AsyncClient();
   _client->onConnect([](void *obj, AsyncClient *c){ ((SyncClient*)(obj))->_onConnect(c); }, this);
+  _attachCallbacks_Disconnect();
 #if ASYNC_TCP_SSL_ENABLED
   if(_client->connect(ip, port, secure)){
 #else
@@ -83,6 +84,7 @@ int SyncClient::connect(const char *host, uint16_t port){
     return 0;
   _client = new AsyncClient();
   _client->onConnect([](void *obj, AsyncClient *c){ ((SyncClient*)(obj))->_onConnect(c); }, this);
+  _attachCallbacks_Disconnect();
 #if ASYNC_TCP_SSL_ENABLED
   if(_client->connect(host, port, secure)){
 #else
@@ -191,16 +193,24 @@ void SyncClient::_onConnect(AsyncClient *c){
     delete b;
   }
   _tx_buffer = new cbuf(_tx_buffer_size);
-  _attachCallbacks();
+  _attachCallbacks_AfterConnected();
 }
 
 void SyncClient::_attachCallbacks(){
+  _attachCallbacks_Disconnect();
+  _attachCallbacks_AfterConnected();
+}
+
+void SyncClient::_attachCallbacks_AfterConnected(){
   _client->onAck([](void *obj, AsyncClient* c, size_t len, uint32_t time){ ((SyncClient*)(obj))->_sendBuffer(); }, this);
-  _client->onDisconnect([](void *obj, AsyncClient* c){ ((SyncClient*)(obj))->_onDisconnect(); delete c; }, this);
   _client->onData([](void *obj, AsyncClient* c, void *data, size_t len){ ((SyncClient*)(obj))->_onData(data, len); }, this);
   _client->onTimeout([](void *obj, AsyncClient* c, uint32_t time){ c->close(); }, this);
 }
 
+void SyncClient::_attachCallbacks_Disconnect(){
+  _client->onDisconnect([](void *obj, AsyncClient* c){ ((SyncClient*)(obj))->_onDisconnect(); delete c; }, this);
+}
+
 size_t SyncClient::write(uint8_t data){
   return write(&data, 1);
 }

src/SyncClient.h

@@ -39,6 +39,8 @@ class SyncClient: public Client {
     void _onConnect(AsyncClient *c);
     void _onDisconnect();
     void _attachCallbacks();
+    void _attachCallbacks_Disconnect();
+    void _attachCallbacks_AfterConnected();
 
   public:
     SyncClient(size_t txBufLen = 1460);