Fix problem with subscribing to multiple topics

app/modules/mqtt.c

@@ -1154,51 +1154,49 @@ static int mqtt_socket_subscribe( lua_State* L ) {
     NODE_DBG("subscribe table\n");
     lua_pushnil( L ); /* first key */
 
-    uint8_t temp_buf[MQTT_BUF_SIZE];
-    uint32_t temp_pos = 0;
+    int topic_count = 0;
     uint8_t overflow = 0;
 
     while( lua_next( L, stack ) != 0 ) {
       topic = luaL_checkstring( L, -2 );
       qos = luaL_checkinteger( L, -1 );
 
-      temp_msg = mqtt_msg_subscribe( &mud->mqtt_state.mqtt_connection, topic, qos, &msg_id );
+      if (topic_count == 0) {
+	temp_msg = mqtt_msg_subscribe_init( &mud->mqtt_state.mqtt_connection, &msg_id );
+      }
+      temp_msg = mqtt_msg_subscribe_topic( &mud->mqtt_state.mqtt_connection, topic, qos );
+      topic_count++;
+
       NODE_DBG("topic: %s - qos: %d, length: %d\n", topic, qos, temp_msg->length);
 
-      if (temp_pos + temp_msg->length > MQTT_BUF_SIZE){
+      if (temp_msg->length == 0) {
         lua_pop(L, 1);
         overflow = 1;
         break;  // too long message for the outbuffer.
       }
-      c_memcpy( temp_buf + temp_pos, temp_msg->data, temp_msg->length );
-      temp_pos += temp_msg->length;
 
       lua_pop( L, 1 );
     }
 
-    if (temp_pos == 0){
-      luaL_error( L, "invalid data" );
-      lua_pushboolean(L, 0);
-      return 1;
+    if (topic_count == 0){
+      return luaL_error( L, "no topics found" );
     }
     if (overflow != 0){
-      luaL_error( L, "buffer overflow, can't enqueue all subscriptions" );
-      lua_pushboolean(L, 0);
-      return 1;
+      return luaL_error( L, "buffer overflow, can't enqueue all subscriptions" );
+    }
+
+    temp_msg = mqtt_msg_subscribe_fini( &mud->mqtt_state.mqtt_connection );
+    if (temp_msg->length == 0) {
+      return luaL_error( L, "buffer overflow, can't enqueue all subscriptions" );
     }
 
-    c_memcpy( temp_buffer, temp_buf, temp_pos );
-    temp_msg->data = temp_buffer;
-    temp_msg->length = temp_pos;
     stack++;
   } else {
     NODE_DBG("subscribe string\n");
     topic = luaL_checklstring( L, stack, &il );
     stack++;
     if( topic == NULL ){
-      luaL_error( L, "need topic name" );
-      lua_pushboolean(L, 0);
-      return 1;
+      return luaL_error( L, "need topic name" );
     }
     qos = luaL_checkinteger( L, stack );
     temp_msg = mqtt_msg_subscribe( &mud->mqtt_state.mqtt_connection, topic, qos, &msg_id );
@@ -1257,17 +1255,13 @@ static int mqtt_socket_publish( lua_State* L )
   }
 
   if(!mud->connected){
-    luaL_error( L, "not connected" );
-    lua_pushboolean(L, 0);
-    return 1;
+    return luaL_error( L, "not connected" );
   }
 
   const char *topic = luaL_checklstring( L, stack, &l );
   stack ++;
   if (topic == NULL){
-    luaL_error( L, "need topic" );
-    lua_pushboolean(L, 0);
-    return 1;
+    return luaL_error( L, "need topic" );
   }
 
   const char *payload = luaL_checklstring( L, stack, &l );

app/mqtt/mqtt_msg.c

@@ -402,14 +402,19 @@ mqtt_message_t* mqtt_msg_pubcomp(mqtt_connection_t* connection, uint16_t message
   return fini_message(connection, MQTT_MSG_TYPE_PUBCOMP, 0, 0, 0);
 }
 
-mqtt_message_t* mqtt_msg_subscribe(mqtt_connection_t* connection, const char* topic, int qos, uint16_t* message_id)
+mqtt_message_t* mqtt_msg_subscribe_init(mqtt_connection_t* connection, uint16_t *message_id)
 {
   init_message(connection);
 
-  if(topic == NULL || topic[0] == '\0')
+  if((*message_id = append_message_id(connection, 0)) == 0)
     return fail_message(connection);
 
-  if((*message_id = append_message_id(connection, 0)) == 0)
+  return &connection->message;
+}
+
+mqtt_message_t* mqtt_msg_subscribe_topic(mqtt_connection_t* connection, const char* topic, int qos)
+{
+  if(topic == NULL || topic[0] == '\0')
     return fail_message(connection);
 
   if(append_string(connection, topic, c_strlen(topic)) < 0)
@@ -419,9 +424,29 @@ mqtt_message_t* mqtt_msg_subscribe(mqtt_connection_t* connection, const char* to
     return fail_message(connection);
   connection->buffer[connection->message.length++] = qos;
 
+  return &connection->message;
+}
+
+mqtt_message_t* mqtt_msg_subscribe_fini(mqtt_connection_t* connection)
+{
   return fini_message(connection, MQTT_MSG_TYPE_SUBSCRIBE, 0, 1, 0);
 }
 
+mqtt_message_t* mqtt_msg_subscribe(mqtt_connection_t* connection, const char* topic, int qos, uint16_t* message_id)
+{
+  mqtt_message_t* result;
+  
+  result = mqtt_msg_subscribe_init(connection, message_id);
+  if (result->length != 0) {
+    result = mqtt_msg_subscribe_topic(connection, topic, qos);
+  }
+  if (result->length != 0) {
+    result = mqtt_msg_subscribe_fini(connection);
+  }
+
+  return result;
+}
+
 mqtt_message_t* mqtt_msg_unsubscribe(mqtt_connection_t* connection, const char* topic, uint16_t* message_id)
 {
   init_message(connection);

app/mqtt/mqtt_msg.h

@@ -120,6 +120,10 @@ 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);
 
+mqtt_message_t* mqtt_msg_subscribe_init(mqtt_connection_t* connection, uint16_t* message_id);
+mqtt_message_t* mqtt_msg_subscribe_topic(mqtt_connection_t* connection, const char* topic, int qos);
+mqtt_message_t* mqtt_msg_subscribe_fini(mqtt_connection_t* connection);
+
 
 #ifdef	__cplusplus
 }