mqtt_client.h

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/******************************************************************************
 * # License
 * <b>Copyright 2021 Silicon Laboratories Inc. www.silabs.com</b>
 ******************************************************************************
 * The licensor of this software is Silicon Laboratories Inc. Your use of this
 * software is governed by the terms of Silicon Labs Master Software License
 * Agreement (MSLA) available at
 * www.silabs.com/about-us/legal/master-software-license-agreement. This
 * software is distributed to you in Source Code format and is governed by the
 * sections of the MSLA applicable to Source Code.
 *
 *****************************************************************************/
 
#ifndef MQTT_CLIENT_H
#define MQTT_CLIENT_H
 
// Standard library
#include <stdbool.h>
#include <unistd.h>
#include <inttypes.h>
 
// Unify components
#include "sl_status.h"
 
#ifndef MQTT_CLIENT_POLL_TIMER_MILLISECONDS
#define MQTT_CLIENT_POLL_TIMER_MILLISECONDS 2000
#endif
 
#ifndef MQTT_CLIENT_KEEP_ALIVE_INTERVAL_MILLISECONDS
#define MQTT_CLIENT_KEEP_ALIVE_INTERVAL_MILLISECONDS 60000
#endif
 
#ifndef MQTT_CLIENT_MINIMUM_RECONNECT_BACKOFF_MILLISECONDS
#define MQTT_CLIENT_MINIMUM_RECONNECT_BACKOFF_MILLISECONDS 1000
#endif
 
#ifndef MQTT_CLIENT_MAXIMUM_RECONNECT_BACKOFF_MILLISECONDS
#define MQTT_CLIENT_MAXIMUM_RECONNECT_BACKOFF_MILLISECONDS 60000
#endif
 
#ifndef MQTT_CLIENT_QoS
#define MQTT_CLIENT_QoS 0
#endif
 
#ifdef __cplusplus
extern "C" {
#endif  // __cplusplus
 
typedef enum {
  MQTT_EVENT_CONNECT,      
  MQTT_EVENT_DISCONNECT,   
  MQTT_EVENT_PUBLISH,      
  MQTT_EVENT_SUBSCRIBE,    
  MQTT_EVENT_UNSUBSCRIBE,  
  MQTT_TRANSITION_DISCONNECTED,  
  MQTT_TRANSITION_CONNECTING,  
  MQTT_TRANSITION_CONNECTED,  
} mqtt_event_t;
// This is really hackish, but I couldn't figure out a way to do this with
// preprocessor-magic but still be able to properly Doxygen-document the
// members of the enum.
__attribute__((unused)) static const char *event_names[]
  = {"MQTT_EVENT_CONNECT",
     "MQTT_EVENT_DISCONNECT",
     "MQTT_EVENT_PUBLISH",
     "MQTT_EVENT_SUBSCRIBE",
     "MQTT_EVENT_UNSUBSCRIBE",
     "MQTT_TRANSITION_DISCONNECTED",
     "MQTT_TRANSITION_CONNECTING",
     "MQTT_TRANSITION_CONNECTED"};
 
struct mqtt_client;
 
typedef struct mqtt_client
  *mqtt_client_t;  
 
typedef void (*message_callback_t)(const char *topic,
                                   const char *message,
                                   const size_t message_length);
 
typedef void (*message_callback_ex_t)(const char *topic,
                                      const char *message,
                                      const size_t message_length,
                                      void *user);
typedef void (*mqtt_connection_callback_t)(mqtt_client_t instance,
                                           const int file_descriptor);
 
typedef void (*mqtt_simple_callback_t)();
 
// C-wrappers. All of those functions have a C++ counterpart within mqtt_client
// or a C++ specific functionality that needs to be bridged to C-land (e.g. new).
 
sl_status_t mqtt_client_setup(mqtt_client_t instance);
 
sl_status_t mqtt_client_teardown(mqtt_client_t instance);
 
int mqtt_client_file_descriptor(mqtt_client_t instance);
 
void mqtt_client_poll(mqtt_client_t instance);
 
void mqtt_client_disconnect(mqtt_client_t instance);
 
void mqtt_client_event(mqtt_client_t instance, const int incoming_event);
 
void mqtt_client_publish(mqtt_client_t instance,
                         const char *topic,
                         const char *message,
                         const size_t message_length,
                         bool retain);
 
void mqtt_client_unretain(mqtt_client_t instance, const char *prefix_pattern);
 
int mqtt_client_count_topics(mqtt_client_t instance,
                             const char *prefix_pattern);
 
void mqtt_client_unretain_by_regex(mqtt_client_t instance, const char *regex);
 
void mqtt_client_subscribe(mqtt_client_t instance,
                           const char *topic,
                           message_callback_t callback);
 
void mqtt_client_subscribe_ex(mqtt_client_t instance,
                              const char *topic,
                              message_callback_ex_t callback,
                              void *user);
 
void mqtt_client_unsubscribe(mqtt_client_t instance,
                             const char *topic,
                             message_callback_t callback);
 
void mqtt_client_unsubscribe_ex(mqtt_client_t instance,
                                const char *topic,
                                message_callback_ex_t callback,
                                void *user);
 
mqtt_client_t mqtt_client_new(
  const char *hostname,
  const uint32_t port,
  const char *client_id,
  const char *cafile,
  const char *certfile,
  const char *keyfile,
  int (*event_sender)(const int event, void *procdata),
  void (*delayed_event_sender)(const int event,
                               const unsigned long milliseconds),
  int (*event_counter)(const int event, void *procdata));
 
void mqtt_client_delete(mqtt_client_t instance);
 
void mqtt_client_on_connect_callback_set(mqtt_client_t instance,
                                         mqtt_connection_callback_t on_connect);
 
void mqtt_client_on_disconnect_callback_set(
  mqtt_client_t instance, mqtt_connection_callback_t on_disconnect);
 
void mqtt_client_before_disconnect_callback_set(
  mqtt_client_t instance, mqtt_simple_callback_t before_disconnect);
 
void mqtt_client_after_connect_callback_set(
  mqtt_client_t instance, mqtt_simple_callback_t after_connect);
 
const char *mqtt_client_get_client_id(const mqtt_client_t client_instance);
 
bool mqtt_client_is_connected_to_broker(const mqtt_client_t instance);
 
#ifdef __cplusplus
}  // extern "C"
#endif  // __cplusplus
 
#endif  // MQTT_CLIENT_H