[added] async.lua

async.lua

@@ -0,0 +1,63 @@
+--[[
+	simple kernel for async tasks running in the background
+]]
+
+local async = class()
+
+function async:new()
+	return self:init({
+		tasks = {},
+	})
+end
+
+--add a task to the kernel
+function async:run(f, args, cb, error_cb)
+	table.insert(self.tasks, {
+		coroutine.create(f),
+		args,
+		cb,
+		error_cb,
+	})
+end
+
+--update some task in the kernel
+function async:update()
+	--grab task definition
+	local td = table.remove(self.tasks, 1)
+	if not td then
+		return false
+	end
+	--run a step
+	local co, args, cb, error_cb = td[1], td[2], td[3], td[4]
+	local success, a, b, c, d, e, f, g, h = coroutine.resume(co, unpack(args))
+	--error?
+	if not success then
+		if error_cb then
+			error_cb(a)
+		else
+			error("failure in async task: "..a)
+		end
+	end
+	--check done
+	if coroutine.status(task) == "dead" then
+		--done? run callback with result
+		cb(a, b, c, d, e, f, g, h)
+	else
+		--if not done, re-add
+		table.insert(self.tasks, taskdef)
+	end
+
+	return true
+end
+
+--update tasks for some amount of time
+function async:update_for_time(t)
+	local now = love.timer.getTime()
+	while love.timer.getTime() - now < t do
+		if not self:update() then
+			break
+		end
+	end
+end
+
+return async