refactor: Group access to output buffer in mqtt_connection_t

  - Moves mqtt_connect_info to mqtt_connection_t.
  - Removes outbound_message in favor of accessing it trough connection.

lib/include/mqtt_client_priv.h

@@ -48,13 +48,10 @@ extern "C" {
 
 typedef struct mqtt_state {
     uint8_t *in_buffer;
-    uint8_t *out_buffer;
     int in_buffer_length;
-    int out_buffer_length;
     size_t message_length;
     size_t in_buffer_read_len;
-    mqtt_message_t *outbound_message;
-    mqtt_connection_t mqtt_connection;
+    mqtt_connection_t connection;
     uint16_t pending_msg_id;
     int pending_msg_type;
     int pending_publish_qos;
@@ -106,7 +103,6 @@ struct esp_mqtt_client {
     esp_transport_handle_t transport;
     mqtt_config_storage_t *config;
     mqtt_state_t  mqtt_state;
-    mqtt_connect_info_t connect_info;
     mqtt_client_state_t state;
     uint64_t refresh_connection_tick;
     int64_t keepalive_tick;

lib/include/mqtt_msg.h

@@ -68,16 +68,6 @@ typedef struct mqtt_message {
     size_t fragmented_msg_data_offset;        /*!< data offset of fragmented messages (zero for all other messages) */
 } mqtt_message_t;
 
-typedef struct mqtt_connection {
-    mqtt_message_t message;
-#if MQTT_MSG_ID_INCREMENTAL
-    uint16_t last_message_id;   /*!< last used id if incremental message id configured */
-#endif
-    uint8_t *buffer;
-    size_t buffer_length;
-
-} mqtt_connection_t;
-
 typedef struct mqtt_connect_info {
     char *client_id;
     char *username;
@@ -90,9 +80,18 @@ typedef struct mqtt_connect_info {
     int will_retain;
     int clean_session;
     esp_mqtt_protocol_ver_t protocol_ver;
-
 } mqtt_connect_info_t;
 
+typedef struct mqtt_connection {
+    mqtt_message_t outbound_message;
+#if MQTT_MSG_ID_INCREMENTAL
+    uint16_t last_message_id;   /*!< last used id if incremental message id configured */
+#endif
+    uint8_t *buffer;
+    size_t buffer_length;
+    mqtt_connect_info_t information;
+
+} mqtt_connection_t;
 
 static inline int mqtt_get_type(const uint8_t *buffer)
 {
@@ -123,7 +122,6 @@ static inline int mqtt_get_retain(const uint8_t *buffer)
     return (buffer[0] & 0x01);
 }
 
-void mqtt_msg_init(mqtt_connection_t *connection, uint8_t *buffer, size_t buffer_length);
 bool mqtt_header_complete(uint8_t *buffer, size_t buffer_length);
 size_t mqtt_get_total_length(const uint8_t *buffer, size_t length, int *fixed_size_len);
 char *mqtt_get_publish_topic(uint8_t *buffer, size_t *length);
@@ -132,6 +130,9 @@ char *mqtt_get_suback_data(uint8_t *buffer, size_t *length);
 uint16_t mqtt_get_id(uint8_t *buffer, size_t length);
 int mqtt_has_valid_msg_hdr(uint8_t *buffer, size_t length);
 
+esp_err_t mqtt_connection_init(mqtt_connection_t *connection, int buffer_size);
+void mqtt_connection_destroy(mqtt_connection_t *connection);
+
 mqtt_message_t *mqtt_msg_connect(mqtt_connection_t *connection, mqtt_connect_info_t *info);
 mqtt_message_t *mqtt_msg_publish(mqtt_connection_t *connection, const char *topic, const char *data, int data_length, int qos, int retain, uint16_t *message_id);
 mqtt_message_t *mqtt_msg_puback(mqtt_connection_t *connection, uint16_t message_id);
@@ -143,8 +144,6 @@ mqtt_message_t *mqtt_msg_unsubscribe(mqtt_connection_t *connection, const char *
 mqtt_message_t *mqtt_msg_pingreq(mqtt_connection_t *connection);
 mqtt_message_t *mqtt_msg_pingresp(mqtt_connection_t *connection);
 mqtt_message_t *mqtt_msg_disconnect(mqtt_connection_t *connection);
-
-
 #ifdef  __cplusplus
 }
 #endif