# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1569775355 -7200
# Node ID 7b48b620164c5ef41caf4bc9e8f94323f398af9a
# Parent  b2ce3300f26a6291b1abd26d4b7611ecbe02f3c9
util.async: Add function for waiting on promises and unpacking the results

diff -r b2ce3300f26a -r 7b48b620164c util/async.lua
--- a/util/async.lua	Sun Sep 29 17:34:47 2019 +0200
+++ b/util/async.lua	Sun Sep 29 18:42:35 2019 +0200
@@ -246,9 +246,25 @@
 	return pcall(checkthread);
 end
 
+local function wait(promise)
+	local async_wait, async_done = waiter();
+	local ret, err = nil, nil;
+	promise:next(
+		function (r) ret = r; end,
+		function (e) err = e; end)
+		:finally(async_done);
+	async_wait();
+	if ret then
+		return ret;
+	else
+		return nil, err;
+	end
+end
+
 return {
 	ready = ready;
 	waiter = waiter;
 	guarder = guarder;
 	runner = runner;
+	wait = wait;
 };