start mqtt client (based on paho.mqtt.c), basically works

libs/main/mqtt_common/pimqtttypes.h

@@ -0,0 +1,68 @@
+//! \~\file pimqtttypes.h
+//! \~\ingroup MQTT
+//! \~\brief
+//! \~english
+//! \~russian
+/*
+	PIP - Platform Independent Primitives
+	MQTT common types
+	Ivan Pelipenko peri4ko@yandex.ru
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Lesser General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Lesser General Public License for more details.
+
+	You should have received a copy of the GNU Lesser General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef pimqtttypes_h
+#define pimqtttypes_h
+
+#include "pip_export.h"
+#include "pistring.h"
+
+
+//! \~english Namespace with shared MQTT data types.
+//! \~russian Пространство имен с общими MQTT-типами данных.
+namespace PIMQTT {
+
+
+//! \~english MQTT QoS type.
+//! \~russian MQTT тип QoS.
+enum class QoS {
+	Level0 = 0 /** \~english Fire and forget - the message may not be delivered.  */,
+	Level1 = 1 /** \~english At least once - the message will be delivered, but may be delivered more than once in some circumstances.  */,
+	Level2 = 2 /** \~english Once and one only - the message will be delivered exactly once.  */,
+};
+
+enum class Error {
+	Unknown                     = 0 /** */,
+	UnacceptableProtocolVersion = 1 /** */,
+	IdentifierRejected          = 2 /** */,
+	ServerUnavailable           = 3 /** */,
+	BadUsernameOrPassword       = 4 /** */,
+	NotAuthorized               = 5 /** */,
+};
+
+struct PIP_EXPORT Message {
+	bool isValid() const { return topic.isNotEmpty(); }
+	PIString topic;
+	PIByteArray payload;
+	PIMap<int, PIString> properties; // for v5
+	QoS qos           = QoS::Level0;
+	int msg_id        = 0;
+	bool is_duplicate = false;
+};
+
+
+}; // namespace PIMQTT
+
+
+#endif