Add vl_scheduler.after() that acts like after() except it takes a priority as param 2, add tests for background tests, fix appending to existing list for next timestep

mods/CORE/vl_scheduler/init.lua

@@ -144,11 +144,13 @@ local function globalstep(dtime)
 	-- Launch asynchronous tasks that may be issued any time (background-async)
 	local next_background_async_task = run_queue[3]
 	local last_background_async_task = next_background_async_task and next_background_async_task.last
-	while next_background_async_task and (core.get_us_time() - start) < BUDGET do
+	local now = core.get_us_time()
+	while next_background_async_task and (now - start) < BUDGET do
 		next_background_async_task:func()
 		local task = next_background_async_task
 		next_background_async_task = next_background_async_task.next
 		free_task(task)
+		now = core.get_us_time()
 	end
 	if next_background_async_task then
 		next_background_async_task.last = last_background_async_task
@@ -158,11 +160,13 @@ local function globalstep(dtime)
 	-- Run tasks that may be run on any timestep (background-main)
 	local next_background_task = run_queue[4]
 	local last_background_task = next_background_task and next_background_task.last
-	while next_background_task and (core.get_us_time() - start) < BUDGET do
+	local now = core.get_us_time()
+	while next_background_task and (now - start) < BUDGET do
 		next_background_task:func()
 		local task = next_background_task
 		next_background_task = next_background_task.next
 		free_task(task)
+		now = core.get_us_time()
 	end
 	if next_background_task then
 		next_background_task.last = last_background_task
@@ -191,6 +195,7 @@ local function queue_task(when, priority, task)
 		task.next = nil
 		if queue then
 			queue.last.next = task
+			queue.last = task
 		else
 			task.last = task
 			run_queue[priority] = task
@@ -215,15 +220,20 @@ local function queue_task(when, priority, task)
 end
 vl_scheduler.queue_task = queue_task
 
--- Hijack core.after and redirect to this scheduler
-function core.after(time, func, ...)
+local function vl_scheduler_after(time, priority, func, ...)
 	local task = new_task()
 	task.args = {...}
 	task.next = nil
 	task.real_func = func
 	task.func = function(task) task.real_func(unpack(task.args)) end
 	local timesteps = math.round(time / 0.05)
-	queue_task(timesteps, 2, task)
+	queue_task(timesteps, priority, task)
+end
+vl_scheduler.after = vl_scheduler_after
+
+-- Hijack core.after and redirect to this scheduler
+function core.after(time, func, ...)
+	vl_scheduler_after(time, 2, func, ...)
 end
 
 return vl_scheduler

mods/CORE/vl_scheduler/unit-test.lua

@@ -1,6 +1,8 @@
 local posix = require 'posix'
 
 _G.core = {}
+_G.dump = dump
+dofile("../../../tests/lib/misc_helpers.lua")
 local mod_paths = {
 	vl_scheduler = "./",
 }
@@ -8,6 +10,11 @@ local mod_paths = {
 local on_mods_loaded
 local globalsteps = 0
 local last_fake_globalstep_dtime
+local time_offset = 0
+
+local function fastforward(amount)
+	time_offset = time_offset + amount
+end
 
 local function init_core()
 	return {
@@ -22,7 +29,7 @@ local function init_core()
 		register_on_mods_loaded = function(func) on_mods_loaded = func end,
 		get_us_time = function()
 			local sec, nsec = posix.clock_gettime(0)
-			return sec * 1e6 + nsec // 1000
+			return sec * 1e6 + nsec // 1000 + time_offset
 		end,
 	}
 end
@@ -121,5 +128,67 @@ describe('vl_scheduler',function()
 		call_globalstep(0.05)
 		assert.is_same(20, num_run)
 	end)
+	it('will not run background tasks if over budget with priority = 3',function()
+		local num_run = 0
+		local vl_scheduler = _G.vl_scheduler
+		vl_scheduler.after(0, 2, function()
+			fastforward(40000)
+		end)
+		for i = 1,50 do
+			vl_scheduler.after(0, 3, function()
+				fastforward(1000)
+				num_run = num_run + 1
+			end)
+		end
+		call_globalstep(0.05)
+		assert.is_same(10, num_run)
+		while(num_run < 50) do
+			call_globalstep(0.05)
+		end
+	end)
+	it('will not run background tasks if over budget with priority = 4',function()
+		local num_run = 0
+		local vl_scheduler = _G.vl_scheduler
+		vl_scheduler.after(0, 2, function()
+			fastforward(40000)
+		end)
+		for i = 1,50 do
+			vl_scheduler.after(0, 4, function()
+				fastforward(1000)
+				num_run = num_run + 1
+			end)
+		end
+		call_globalstep(0.05)
+		assert.is_same(10, num_run)
+		while(num_run < 50) do
+			call_globalstep(0.05)
+		end
+	end)
+	it('will not run background tasks if over budget with mixed priority',function()
+		local num_3_run = 0
+		local num_4_run = 0
+		local vl_scheduler = _G.vl_scheduler
+		vl_scheduler.after(0, 2, function()
+			fastforward(40000)
+		end)
+		for i = 1,10 do
+			vl_scheduler.after(0, 3, function()
+				fastforward(500)
+				num_3_run = num_3_run + 1
+			end)
+		end
+		for i = 1,20 do
+			vl_scheduler.after(0, 4, function()
+				fastforward(500)
+				num_4_run = num_4_run + 1
+			end)
+		end
+		call_globalstep(0.05)
+		assert.is_same(10, num_3_run)
+		assert.is_same(10, num_4_run)
+		while(num_4_run < 20) do
+			call_globalstep(0.05)
+		end
+	end)
 end)