Function wallet_utxo_boost

wallet/wallet.c:642–711

Gather enough utxos to meet feerate, otherwise all we can. */

/* Gather enough utxos to meet feerate, otherwise all we can. */
struct utxo **wallet_utxo_boost(const tal_t *ctx,
				struct wallet *w,
				u32 blockheight,
				struct amount_sat excess_sats,
				struct amount_sat output_sats_required,
				u32 feerate_target,
				size_t *weight,
				bool *insufficient)
{
	struct utxo **all_utxos = wallet_get_unspent_utxos(tmpctx, w);
	struct utxo **utxos = tal_arr(ctx, struct utxo *, 0);
	u32 feerate;

	/* Select in random order */
	tal_arr_randomize(all_utxos, struct utxo *);

	feerate = calc_feerate(excess_sats, output_sats_required, *weight);

	for (size_t i = 0; i < tal_count(all_utxos); i++) {
		u32 new_feerate;
		size_t new_weight;
		struct amount_sat new_excess_sats;
		/* Convenience var */
		struct utxo *utxo = all_utxos[i];

		/* Are we already happy? */
		if (feerate >= feerate_target) {
			log_debug(w->log, "wallet_utxo_boost: got %zu UTXOs, excess %s (needed %s), weight %zu, feerate %u >= %u",
				  tal_count(utxos),
				  fmt_amount_sat(tmpctx, excess_sats),
				  fmt_amount_sat(tmpctx, output_sats_required),
				  *weight, feerate, feerate_target);
			if (insufficient)
				*insufficient = false;
			return utxos;
		}

		/* Don't add reserved ones */
		if (utxo_is_reserved(utxo, blockheight))
			continue;

		/* Don't add csv-locked ones */
		if (utxo_is_csv_locked(utxo, blockheight))
			continue;

		/* UTXOs must be sane amounts */
		if (!amount_sat_add(&new_excess_sats,
				    excess_sats, utxo->amount))
			abort();

		new_weight = *weight + utxo_spend_weight(utxo, 0);
		new_feerate = calc_feerate(new_excess_sats, output_sats_required,
					   new_weight);

		/* Don't add uneconomic ones! */
		if (new_feerate < feerate)
			continue;