qmi-codegen: don't mark missing optional TLVs as set

In the optional TLV case, 'tlv_error' was never set to TRUE
when the optional TLV was missing, because the return value of
qmi_message_tlv_read_init() was ignored.  This caused
"self->arg_*_set" to always be TRUE and NULL strings to be
returned to callers requesting the TLV value later.

Also prevent incorrect "Left X bytes unread when getting..."
messages caused when the TLV is missing.

This bug was found when probing a modem that does not return
an MEID TLV to DMSGetIds (because it is GSM/UMTS/LTE only),
but qmi_message_dms_get_ids_output_get_meid() returned TRUE
and a NULL 'str':

    if (qmi_message_dms_get_ids_output_get_meid (output, &str, NULL) &&
-->     str[0] != '\0' && str[0] != '0') {

Bug introduced in b143b7f6 (qmi-codegen: use the new TLV reader API).

Before:
=======

    gsize offset = 0;
    gsize init_offset;
    gboolean tlv_error = FALSE;

    init_offset = qmi_message_tlv_read_init (message, QMI_INDICATION_DMS_EVENT_REPORT_OUTPUT_TLV_POWER_STATE, NULL, NULL);
    <<<snip>>>

    /* The remaining size of the buffer needs to be 0 if we successfully read the TLV */
    if ((offset = __qmi_message_tlv_read_remaining_size (message, init_offset, offset)) > 0) {
        g_warning ("Left '%" G_GSIZE_FORMAT "' bytes unread when getting the 'Power State' TLV", offset);
    }

qmi_indication_dms_event_report_output_power_state_out:
    if (!tlv_error)
        self->arg_power_state_set = TRUE;

After:
======

    gsize offset = 0;
    gsize init_offset;

    if ((init_offset = qmi_message_tlv_read_init (message, QMI_INDICATION_DMS_EVENT_REPORT_OUTPUT_TLV_POWER_STATE, NULL, NULL)) == 0) {
        goto qmi_indication_dms_event_report_output_power_state_out;
    }
    <<<snip>>>

    /* The remaining size of the buffer needs to be 0 if we successfully read the TLV */
    if ((offset = __qmi_message_tlv_read_remaining_size (message, init_offset, offset)) > 0) {
        g_warning ("Left '%" G_GSIZE_FORMAT "' bytes unread when getting the 'Power State' TLV", offset);
    }

    self->arg_power_state_set = TRUE;

qmi_indication_dms_event_report_output_power_state_out:
    ;

0 files changed, 0 insertions, 0 deletions