initial commit for process scheduler

code/controllers/ProcessScheduler/core/updateQueueWorker.dm

@@ -0,0 +1,83 @@
+datum/updateQueueWorker
+	var/tmp/list/objects
+	var/tmp/killed
+	var/tmp/finished
+	var/tmp/procName
+	var/tmp/list/arguments
+	var/tmp/lastStart
+	var/tmp/cpuThreshold
+
+datum/updateQueueWorker/New(var/list/objects, var/procName, var/list/arguments, var/cpuThreshold = 90)
+	..()
+	uq_dbg("updateQueueWorker created.")
+
+	init(objects, procName, arguments, cpuThreshold)
+
+datum/updateQueueWorker/proc/init(var/list/objects, var/procName, var/list/arguments, var/cpuThreshold = 90)
+	src.objects = objects
+	src.procName = procName
+	src.arguments = arguments
+	src.cpuThreshold = cpuThreshold
+
+	killed = 0
+	finished = 0
+
+datum/updateQueueWorker/proc/doWork()
+	// If there's nothing left to execute or we were killed, mark finished and return.
+	if (!objects || !objects.len) return finished()
+
+	lastStart = world.timeofday // Absolute number of ticks since the world started up
+
+	var/datum/object = objects[objects.len] // Pull out the object
+	objects.len-- // Remove the object from the list
+
+	if (istype(object) && !isturf(object) && !object.disposed && isnull(object.gcDestroyed)) // We only work with real objects
+		call(object, procName)(arglist(arguments))
+
+	// If there's nothing left to execute
+	// or we were killed while running the above code, mark finished and return.
+	if (!objects || !objects.len) return finished()
+
+	if (world.cpu > cpuThreshold)
+		// We don't want to force a tick into overtime!
+		// If the tick is about to go overtime, spawn the next update to go
+		// in the next tick.
+		uq_dbg("tick went into overtime with world.cpu = [world.cpu], deferred next update to next tick [1+(world.time / world.tick_lag)]")
+
+		spawn(1)
+			doWork()
+	else
+		spawn(0) // Execute anonymous function immediately as if we were in a while loop...
+			doWork()
+
+datum/updateQueueWorker/proc/finished()
+	uq_dbg("updateQueueWorker finished.")
+	/**
+	 * If the worker was killed while it was working on something, it
+	 * should delete itself when it finally finishes working on it.
+	 * Meanwhile, the updateQueue will have proceeded on with the rest of
+	 * the queue. This will also terminate the spawned function that was
+	 * created in the kill() proc.
+	 */
+	if(killed)
+		del(src)
+
+	finished = 1
+
+datum/updateQueueWorker/proc/kill()
+	uq_dbg("updateQueueWorker killed.")
+	killed = 1
+	objects = null
+
+	/**
+	 * If the worker is not done in 30 seconds after it's killed,
+	 * we'll forcibly delete it, causing the anonymous function it was
+	 * running to be terminated. Hasta la vista, baby.
+	 */
+	spawn(300)
+		del(src)
+
+datum/updateQueueWorker/proc/start()
+	uq_dbg("updateQueueWorker started.")
+	spawn(0)
+		doWork()