v76a Unsafe call!!!!!

Monkey Forums/Monkey Programming/v76a Unsafe call!!!!!

Skn3	(Posted 2013) [#1]

Just messing around with creating a very simple lock/unlock mutex mechanism.

On unsupported devices I want to fake the mutex system so I just added a Mutex class that handles this. For native code I will eventually use native locking calls to handle the locks.

Strict

Import mojo

Function Main:Int()
	New MyApp
	Return 0
End

Class Mutex
	Field lockTicket:Int = 0
	Field unlockTicket:Int = 0
	
	Method Lock:Void()
		' --- fake lock the mutex ---
		'get a new lock ticket
		Local myTicket:= lockTicket
		lockTicket += 1
		
		'can we return yet
		While unlockTicket <> myTicket
		Wend
	End
	
	Method Unlock:Void()
		' --- fake unlock mutex ---
		'increase unlock ticket
		unlockTicket += 1
	End
End

Global mutex:= New Mutex()
Global sharedIndex:Int

Class Task1 Extends Thread
	Method Run__UNSAFE__:Void()
		' --- run task ---
		Print "task1:start"
		mutex.Lock()
			Local timestamp:Int = Millisecs()
			Local ms:Int
			
			For sharedIndex = 0 Until 10
				Print "task1:sharedindex = '" + sharedIndex + "'"
				
				'wait for some time
				Repeat
					ms = Millisecs()
					If ms >= timestamp + 500
						timestamp = ms
						Exit
					EndIf
				Forever
			Next
		mutex.Unlock()
		Print "task1:end"
	End
End

Class Task2 Extends Thread
	Method Run__UNSAFE__:Void()
		' --- run task ---
		Print "task2:start"
		mutex.Lock()
			Local timestamp:Int = Millisecs()
			Local ms:Int
			
			For sharedIndex = 11 Until 20
				Print "task2:sharedindex = '" + sharedIndex + "'"
				
				'wait for some time
				Repeat
					ms = Millisecs()
					If ms >= timestamp + 250
						timestamp = ms
						Exit
					EndIf
				Forever
			Next
		mutex.Unlock()
		Print "task2:end"
	End
End

Class MyApp Extends App
	'monkey events
	Method OnCreate:Int()
		' --- setup the game ---
		SetUpdateRate(60)

		'create some tasks
		Local task1:= New Task1
		Local task2:= New Task2
		
		'start them together
		'they will bother be running at the same time but hopefully task2 will happen after :)
		task1.Start()
		task2.Start()
		
		Return 0
	End
	
	Method OnUpdate:Int()
		' --- update the game ---
		'basic app update
		If KeyHit(KEY_ESCAPE) Error("")

		'weird return
		Return 0
	End
	
	Method OnRender:Int()
		' --- render the game ---
		'clear screen
		Cls(Rnd(0, 255), Rnd(0, 255), Rnd(0, 255))
		
		'weird return
		Return 0
	End
End

This works fine on android, but if I compile for glfw I get:

ATTENTION: Compilation error reported by Trans: Unsafe call!!!!!

marksibly

(Posted 2013) [#2]

brl.thread is really meant for internal use only - in particular, gc is single threaded so calling Monkey functions on a thread can be decidedly deadly if gc ends up being invoked.

To that end, there's some fudge in there that means method/function names with __UNSAFE__ in them can only other __UNSAFE__ methods/functions - or, native methods/functions.

Skn3	(Posted 2013) [#3]

Ah ok cheers for the clarification. Any plans on improving the threading support to make it more robust?

Some basic block control and signalling would be helpful.

Samah

(Posted 2013) [#4]

I suppose I could finish off Diddy's threading side-project...
There's a couple of unimplemented targets, but other than that it's essentially a simplified posix-thread implementation.

https://code.google.com/p/diddy/source/browse/#hg%2Fsrc%2Fthreading