Function mw_load_outputs

plugins/spender/multiwithdraw.c:564–615

mw_sign_and_send(struct multiwithdraw_command *mw);

static struct command_result *
mw_load_outputs(struct multiwithdraw_command *mw)
{
	/* Insert outputs at random locations.  */
	for (size_t i = 0; i < tal_count(mw->outputs); ++i) {
		struct wally_psbt_output *out;
		/* There are already `i` outputs at this point,
		 * select from 0 to `i` inclusive, with 0 meaning
		 * "before first output" and `i` meaning "after
		 * last output".  */
		size_t point = pseudorand(i + 1);
		out = psbt_insert_output(mw->psbt,
					 mw->outputs[i].script,
					 mw->outputs[i].amount,
					 point);
		if (mw->outputs[i].is_to_external)
			psbt_output_mark_as_external(mw->psbt, out);
	}

	if (chainparams->is_elements) {
		struct amount_sat sum = AMOUNT_SAT(0);
		/* Elements transactions have a fee output.
		 * Bitcoin assumes fee = inputs - outputs, so just
		 * do that here.  */
		for (size_t i = 0; i < mw->psbt->num_inputs; ++i)
			if (!amount_sat_add(&sum, sum,
					    psbt_input_get_amount(mw->psbt,
								  i)))
				plugin_err(mw->cmd->plugin,
					   "Overflow in summing inputs.");
		for (size_t i = 0; i < mw->psbt->num_outputs; ++i)
			if (!amount_sat_sub(&sum, sum,
					    psbt_output_get_amount(mw->psbt,
								   i))) {
				/* Not enough already.  */
				sum = AMOUNT_SAT(0);
				break;
			}

		/* We always add this at the end.
		 * The fee output is fairly obvious --- it is
		 * the one without a SCRIPT --- so it is actually
		 * pointless to shuffle it with the rest of the
		 * outputs, since it will never fool chain analysis.  */
		if (!amount_sat_eq(sum, AMOUNT_SAT(0)))
			psbt_append_output(mw->psbt,
					   NULL,
					   sum);
	}

	return mw_sign_and_send(mw);
}

/*-----------------------------------------------------------------------------
Sign and Send PSBT