Events: Add new event to report deleted messages from outbox

include/mqtt_client.h

@@ -57,6 +57,13 @@ typedef enum {
                                         and current data offset updating.
                                          */
     MQTT_EVENT_BEFORE_CONNECT,     /*!< The event occurs before connecting */
+    MQTT_EVENT_DELETED,            /*!< Notification on delete of one message from the internal outbox,
+                                        if the message couldn't have been sent and acknowledged before expiring
+                                        defined in OUTBOX_EXPIRED_TIMEOUT_MS.
+                                        (events are not posted upon deletion of successfully acknowledged messages)
+                                        - This event id is posted only if MQTT_REPORT_DELETED_MESSAGES==1
+                                        - Additional context: msg_id (id of the deleted message).
+                                        */
 } esp_mqtt_event_id_t;
 
 /**

lib/include/mqtt_config.h

@@ -19,6 +19,8 @@
 
 #define MQTT_SKIP_PUBLISH_IF_DISCONNECTED CONFIG_MQTT_SKIP_PUBLISH_IF_DISCONNECTED
 
+#define MQTT_REPORT_DELETED_MESSAGES CONFIG_MQTT_REPORT_DELETED_MESSAGES
+
 #if CONFIG_MQTT_BUFFER_SIZE
 #define MQTT_BUFFER_SIZE_BYTE       CONFIG_MQTT_BUFFER_SIZE
 #else

lib/include/mqtt_outbox.h

@@ -44,6 +44,12 @@ esp_err_t outbox_delete(outbox_handle_t outbox, int msg_id, int msg_type);
 esp_err_t outbox_delete_msgid(outbox_handle_t outbox, int msg_id);
 esp_err_t outbox_delete_msgtype(outbox_handle_t outbox, int msg_type);
 int outbox_delete_expired(outbox_handle_t outbox, outbox_tick_t current_tick, outbox_tick_t timeout);
+/**
+ * @brief Deletes single expired message returning it's message id
+ *
+ * @return msg id of the deleted message, -1 if no expired message in the outbox
+ */
+int outbox_delete_single_expired(outbox_handle_t outbox, outbox_tick_t current_tick, outbox_tick_t timeout);
 
 esp_err_t outbox_set_pending(outbox_handle_t outbox, int msg_id, pending_state_t pending);
 esp_err_t outbox_set_tick(outbox_handle_t outbox, int msg_id, outbox_tick_t tick);

lib/mqtt_outbox.c

@@ -153,6 +153,22 @@ esp_err_t outbox_delete_msgtype(outbox_handle_t outbox, int msg_type)
     }
     return ESP_OK;
 }
+int outbox_delete_single_expired(outbox_handle_t outbox, outbox_tick_t current_tick, outbox_tick_t timeout)
+{
+    int msg_id = -1;
+    outbox_item_handle_t item, tmp;
+    STAILQ_FOREACH_SAFE(item, outbox, next, tmp) {
+        if (current_tick - item->tick > timeout) {
+            STAILQ_REMOVE(outbox, item, outbox_item, next);
+            free(item->buffer);
+            msg_id = item->msg_id;
+            free(item);
+            return msg_id;
+        }
+
+    }
+    return msg_id;
+}
 
 int outbox_delete_expired(outbox_handle_t outbox, outbox_tick_t current_tick, outbox_tick_t timeout)
 {

mqtt_client.c

@@ -1282,6 +1282,31 @@ static esp_err_t mqtt_resend_queued(esp_mqtt_client_handle_t client, outbox_item
     return ESP_OK;
 }
 
+static void mqtt_delete_expired_messages(esp_mqtt_client_handle_t client)
+{
+    // Delete message after OUTBOX_EXPIRED_TIMEOUT_MS milliseconds
+#if MQTT_REPORT_DELETED_MESSAGES
+    // also report the deleted items as MQTT_EVENT_DELETED events if enabled
+    int deleted_items = 0;
+    int msg_id = 0;
+    while ((msg_id = outbox_delete_single_expired(client->outbox, platform_tick_get_ms(), OUTBOX_EXPIRED_TIMEOUT_MS)) > 0) {
+        client->event.event_id = MQTT_EVENT_DELETED;
+        client->event.msg_id = msg_id;
+        if (esp_mqtt_dispatch_event(client) != ESP_OK) {
+            ESP_LOGE(TAG, "Failed to post event on deleting message id=%d", msg_id);
+        }
+        deleted_items ++;
+    }
+#else
+    int deleted_items = outbox_delete_expired(client->outbox, platform_tick_get_ms(), OUTBOX_EXPIRED_TIMEOUT_MS);
+#endif
+    client->mqtt_state.pending_msg_count -= deleted_items;
+
+    if (client->mqtt_state.pending_msg_count < 0) {
+        client->mqtt_state.pending_msg_count = 0;
+    }
+}
+
 static void esp_mqtt_task(void *pv)
 {
     esp_mqtt_client_handle_t client = (esp_mqtt_client_handle_t) pv;
@@ -1353,13 +1378,8 @@ static void esp_mqtt_task(void *pv)
                 break;
             }
 
-            //Delete message after OUTBOX_EXPIRED_TIMEOUT_MS miliseconds
+            // delete long pending messages
-            int deleted = outbox_delete_expired(client->outbox, platform_tick_get_ms(), OUTBOX_EXPIRED_TIMEOUT_MS);
+            mqtt_delete_expired_messages(client);
-            client->mqtt_state.pending_msg_count -= deleted;
-
-            if (client->mqtt_state.pending_msg_count < 0) {
-                client->mqtt_state.pending_msg_count = 0;
-            }
 
             // resend all non-transmitted messages first
             outbox_item_handle_t item = outbox_dequeue(client->outbox, QUEUED, NULL);
@@ -1674,13 +1694,8 @@ int esp_mqtt_client_publish(esp_mqtt_client_handle_t client, const char *topic,
             ret = pending_msg_id;
         }
 
-        // Delete message after OUTBOX_EXPIRED_TIMEOUT_MS milliseconds
+        // delete long pending messages
-        int deleted = outbox_delete_expired(client->outbox, platform_tick_get_ms(), OUTBOX_EXPIRED_TIMEOUT_MS);
+        mqtt_delete_expired_messages(client);
-        client->mqtt_state.pending_msg_count -= deleted;
-
-        if (client->mqtt_state.pending_msg_count < 0) {
-            client->mqtt_state.pending_msg_count = 0;
-        }
 
         goto cannot_publish;
     }