Function psbt_elements_normalize_fees

bitcoin/psbt.c:524–572

}

void psbt_elements_normalize_fees(struct wally_psbt *psbt)
{
	size_t fee_output_idx = psbt->num_outputs;

	if (!is_elements(chainparams))
		return;

	/* Elements requires that every input value is accounted for,
	 * including the fees */
	struct amount_sat total_fee = AMOUNT_SAT(0), val;
	for (size_t i = 0; i < psbt->num_inputs; i++) {
		val = psbt_input_get_amount(psbt, i);
		if (!amount_sat_add(&total_fee, total_fee, val))
			return;
	}
	for (size_t i = 0; i < psbt->num_outputs; i++) {
		struct amount_asset output_amount = wally_psbt_output_get_amount(&psbt->outputs[i]);
		if (elements_psbt_output_is_fee(psbt, i)) {
			if (fee_output_idx == psbt->num_outputs) {
				fee_output_idx = i;
				continue;
			}
			/* We already have at least one fee output,
			 * remove this one */
			psbt_rm_output(psbt, i--);
			continue;
		}
		if (!amount_asset_is_main(&output_amount))
			continue;

		if (!amount_sat_sub(&total_fee, total_fee,
				    amount_asset_to_sat(&output_amount)))
			return;
	}

	if (amount_sat_eq(total_fee, AMOUNT_SAT(0)))
		return;

	/* We need to add a fee output */
	if (fee_output_idx == psbt->num_outputs) {
		psbt_append_output(psbt, NULL, total_fee);
	} else {
		int ret;
		u64 sats = total_fee.satoshis; /* Raw: wally API */
		struct wally_psbt_output *out = &psbt->outputs[fee_output_idx];
		ret = wally_psbt_output_set_amount(out, sats);
		assert(ret == WALLY_OK);
	}
}

void wally_psbt_input_get_txid(const struct wally_psbt_input *in,
			       struct bitcoin_txid *txid)