fixup! added Mqtt client Interface definition

Author: andreagilardoni

src/MqttInterface.h

@@ -1,32 +1,34 @@
 #pragma once
 #include <functional>
-#include <memory>
-
-// https://github.com/arduino-libraries/ArduinoMqttClient/
+#include <Client.h>
 
 // The Idea for this section of the library is to allow the usage of different implementation for Mqtt Clients
 // while preserving the possibility of having an Arduino standardized interface for Mqtt protocol
 // One should implement MqttClientInterface and provide a way to instantiate the implementation
 
 // namespace arduino { // namespace net { namespace mqtt {
+typedef int error_t; // TODO move this to be generally available
 
 class IStream {
 public:
     virtual ~IStream() = default;
 
     virtual int available() = 0;
     virtual int read() = 0;
-    virtual int peek() = 0;
+    // virtual int peek() = 0;
     virtual size_t readBytes(uint8_t *buffer, size_t length) = 0; // read chars from stream into buffer
 };
 
-class OStream {
+class MqttOStream { // if OStream becomes available in arduino core api, we still need to extend its definition
 public:
-    virtual ~OStream() = default;
+    MqttOStream(error_t rc=0): rc(rc) {}
+    virtual ~MqttOStream() = default;
 
     virtual size_t write(uint8_t) = 0;
     virtual size_t write(const uint8_t *buffer, size_t size) = 0;
     virtual int availableForWrite() = 0;
+
+    const error_t rc;
 };
 
 using Topic = const char* const;
@@ -38,34 +40,34 @@ using MqttReceiveCallback = std::function<void(Topic, IStream&)>;
 
 // TODO define callback for mqtt events. one should be the default, but the user can always change it
 
-typedef int error_t; // TODO move this to be generally available
-
 // copied from zephyr
-enum mqtt_conn_return_code {
-	/** Connection accepted. */
-	MQTT_CONNECTION_ACCEPTED                = 0x00,
-
-	/** The Server does not support the level of the MQTT protocol
-	 * requested by the Client.
-	 */
-	MQTT_UNACCEPTABLE_PROTOCOL_VERSION      = 0x01,
-
-	/** The Client identifier is correct UTF-8 but not allowed by the
-	 *  Server.
-	 */
-	MQTT_IDENTIFIER_REJECTED                = 0x02,
-
-	/** The Network Connection has been made but the MQTT service is
-	 *  unavailable.
-	 */
-	MQTT_SERVER_UNAVAILABLE                 = 0x03,
-
-	/** The data in the user name or password is malformed. */
-	MQTT_BAD_USER_NAME_OR_PASSWORD          = 0x04,
-
-	/** The Client is not authorized to connect. */
-	MQTT_NOT_AUTHORIZED                     = 0x05
-};
+// enum mqtt_conn_return_code: error_t {
+// 	/** Connection accepted. */
+// 	MQTT_CONNECTION_ACCEPTED                = 0x00,
+
+// 	/** The Server does not support the level of the MQTT protocol
+// 	 * requested by the Client.
+// 	 */
+// 	MQTT_UNACCEPTABLE_PROTOCOL_VERSION      = 0x01,
+
+// 	/** The Client identifier is correct UTF-8 but not allowed by the
+// 	 *  Server.
+// 	 */
+// 	MQTT_IDENTIFIER_REJECTED                = 0x02,
+
+// 	/** The Network Connection has been made but the MQTT service is
+// 	 *  unavailable.
+// 	 */
+// 	MQTT_SERVER_UNAVAILABLE                 = 0x03,
+
+// 	/** The data in the user name or password is malformed. */
+// 	MQTT_BAD_USER_NAME_OR_PASSWORD          = 0x04,
+
+// 	/** The Client is not authorized to connect. */
+// 	MQTT_NOT_AUTHORIZED                     = 0x05
+// };
+
+constexpr error_t NotImplementedError= -0x100; // TODO define a proper value
 
 enum MqttQos: uint8_t {
     MqttQos0 = 0, // At Most once
@@ -74,8 +76,8 @@ enum MqttQos: uint8_t {
 };
 
 typedef uint8_t MqttPublishFlag;
-enum class MqttPublishFlags: MqttPublishFlag {
-    None            = 0;
+enum MqttPublishFlags: MqttPublishFlag {
+    None            = 0,
     RetainEnabled   = 1,
     DupEnabled      = 2,
 };
@@ -93,6 +95,7 @@ class MqttClientInterface {
 
     virtual error_t connect(IPAddress ip, uint16_t port) = 0;
     virtual error_t connect(const char *host, uint16_t port) = 0; // TODO should host be string instead of c-string?
+    virtual void disconnect() = 0;
 
     virtual error_t subscribe(Topic t, MqttQos qos = QosDefault) = 0;
 
@@ -107,7 +110,7 @@ class MqttClientInterface {
      * an mqtt Message, from the opening header to its termaination.
      * The concrete OStream is defined by the implementation
      */
-    virtual OStream& publish( // TODO should OStream keep publish error information?
+    virtual MqttOStream&& publish(
         Topic t, MqttQos qos = QosDefault,
         MqttPublishFlag flags = MqttPublishFlags::None) = 0;
 
@@ -121,16 +124,16 @@ class MqttClientInterface {
     virtual void setId(const char* client_id = nullptr) = 0;
 
     // password may be null, if username is null password won't be used
-    virtual void setAuth(const char* username, const char* password=nullptr) = 0;
+    virtual void setUsernamePassword(const char* username, const char* password=nullptr) = 0;
 
     virtual void setWill(
         Topic willTopic, const uint8_t* will_message,
         size_t will_size, MqttQos qos=QosDefault,
         MqttPublishFlag flags = MqttPublishFlags::None) = 0;
 
-    virtual void setClient(Client*) = 0;
+    virtual void setClient(arduino::Client*) = 0;
 
-    // may cause errors since one can easily pass a context dependent object
+    // FIXME the following definition may cause errors since one can easily pass a context dependent object
     // virtual void setClient(Client&) = 0;
     // Could this be a better solution?
     // virtual void setClient(Client&&) = 0;