Function closing_tx_weight_estimate

closingd/closingd.c:570–595

Figure out what weight we actually expect for this closing tx (using zero fees * gives the largest possible tx: larger values might omit outputs). */

/* Figure out what weight we actually expect for this closing tx (using zero fees
 * gives the largest possible tx: larger values might omit outputs). */
static size_t closing_tx_weight_estimate(u8 *scriptpubkey[NUM_SIDES],
					 const u8 *funding_wscript,
					 const struct amount_sat *out,
					 struct amount_sat funding_sats,
					 struct amount_sat dust_limit,
					 u32 *local_wallet_index,
					 const struct ext_key *local_wallet_ext_key)
{
	/* We create a dummy close */
	struct bitcoin_tx *tx;
	struct bitcoin_outpoint dummy_funding;

	memset(&dummy_funding, 0, sizeof(dummy_funding));
	tx = create_close_tx(tmpctx, chainparams,
			     local_wallet_index, local_wallet_ext_key,
			     scriptpubkey[LOCAL], scriptpubkey[REMOTE],
			     funding_wscript,
			     &dummy_funding,
			     funding_sats,
			     out[LOCAL],
			     out[REMOTE],
			     dust_limit);

	/* We will have to append the witness */
	return bitcoin_tx_weight(tx) + bitcoin_tx_2of2_input_witness_weight();
}

/* Get the minimum and desired fees */
static void calc_fee_bounds(size_t expected_weight,