int aws_mqtt_packet_connect_encode()

in source/packets.c [206:284]

• 47 lines of code
• 16 McCabe index (conditional complexity)

int aws_mqtt_packet_connect_encode(struct aws_byte_buf *buf, const struct aws_mqtt_packet_connect *packet) {

    AWS_PRECONDITION(buf);
    AWS_PRECONDITION(packet);

    /* Do validation */
    if (packet->has_password && !packet->has_username) {

        return aws_raise_error(AWS_ERROR_MQTT_INVALID_CREDENTIALS);
    }

    /*************************************************************************/
    /* Fixed Header */

    if (aws_mqtt_fixed_header_encode(buf, &packet->fixed_header)) {
        return AWS_OP_ERR;
    }

    /*************************************************************************/
    /* Variable Header                                                       */

    /* Write protocol name */
    if (s_encode_buffer(buf, s_protocol_name)) {
        return aws_raise_error(AWS_ERROR_SHORT_BUFFER);
    }

    /* Write protocol level */
    if (!aws_byte_buf_write_u8(buf, S_PROTOCOL_LEVEL)) {
        return aws_raise_error(AWS_ERROR_SHORT_BUFFER);
    }

    /* Write connect flags [MQTT-3.1.2.3] */
    uint8_t connect_flags = (uint8_t)(
        packet->clean_session << 1 | packet->has_will << 2 | packet->will_qos << 3 | packet->will_retain << 5 |
        packet->has_password << 6 | packet->has_username << 7);

    if (!aws_byte_buf_write_u8(buf, connect_flags)) {
        return aws_raise_error(AWS_ERROR_SHORT_BUFFER);
    }

    /* Write keep alive */
    if (!aws_byte_buf_write_be16(buf, packet->keep_alive_timeout)) {
        return aws_raise_error(AWS_ERROR_SHORT_BUFFER);
    }

    /*************************************************************************/
    /* Payload                                                               */

    /* Client identifier is required, write it */
    if (s_encode_buffer(buf, packet->client_identifier)) {
        return AWS_OP_ERR;
    }

    /* Write will */
    if (packet->has_will) {
        if (s_encode_buffer(buf, packet->will_topic)) {
            return AWS_OP_ERR;
        }
        if (s_encode_buffer(buf, packet->will_message)) {
            return AWS_OP_ERR;
        }
    }

    /* Write username */
    if (packet->has_username) {
        if (s_encode_buffer(buf, packet->username)) {
            return AWS_OP_ERR;
        }
    }

    /* Write password */
    if (packet->has_password) {
        if (s_encode_buffer(buf, packet->password)) {
            return AWS_OP_ERR;
        }
    }

    return AWS_OP_SUCCESS;
}