[Resolved] Is this code by any way leaking?

Solar2D General Questions/Discussion
#1

Feel free to copy it and test it in corona.
What i am trying to do here is to create a module that creates objects with event listeners.

Memory usage seems to go up a bit, but i am not sure how that is calculated. Sometimes it just falls back. Texture memory is not leaking though.

My main concern is whether i removed the listener for the object when i call myObj:removeSelf().
To test this:

  • Try touching screen once to create a red square randomly on screen
  • Then wait 5 seconds for it to be remove, notice the memory used (not texture)
  • After that, touch the screen 3 times to create 3 red squares.
  • Then wait 5 seconds for it to be remove, the memory used increased ]:

Code:

-- main.lua  
local oc = require "oc"  
  
local function garbagePrinting()  
 collectgarbage("collect")  
 local memUsage\_str = string.format( "memUsage = %.3f KB", collectgarbage( "count" ) )  
 print( memUsage\_str )  
 local texMemUsage\_str = system.getInfo( "textureMemoryUsed" )  
 texMemUsage\_str = texMemUsage\_str/1000  
 texMemUsage\_str = string.format( "texMemUsage = %.3f MB", texMemUsage\_str )  
 print( texMemUsage\_str )  
end  
  
local function test( event )  
 if event.phase == "ended" then  
  
 print( "========================" )  
 print( "Before creating object:" )  
 garbagePrinting()  
 print( "========================" )  
  
  
 local myObj = oc.createObject( "redsquare" )  
  
 print( myObj.actions[1] )  
  
 myObj.x = math.random( 32, display.contentWidth - 32 )  
 myObj.y = math.random( 32, display.contentHeight - 32 )  
  
 print( "========================" )  
 print( "After creating object:" )  
 garbagePrinting()  
 print( "========================" )  
  
  
 local function removeObj()  
 myObj:removeSelf()  
 print( "========================" )  
 print( "After removing object:" )  
 garbagePrinting()  
 print( "========================" )  
 end  
  
 timer.performWithDelay( 5000, removeObj )  
 end  
  
 return true  
end  
  
Runtime:addEventListener( "touch", test )  
-- object creator (oc.lua)  
local OC = {}  
  
--private  
local function testTouch( event )  
 if event.phase == "ended" then  
 print( "touched" )  
 end  
  
 return true  
end  
  
--public  
local function createObj( objName )  
 local obj = display.newGroup()  
 local image = display.newImage( objName .. ".png" )  
  
 obj:insert( image )  
  
 obj.actions = { "collect", "eat", "cancel" }  
  
 obj:addEventListener( "touch", testTouch )  
  
 return obj  
end  
  
OC.createObject = createObj  
return OC

If i am leaking any where please let me know as i want to convert this to handle something huge.

Thanks for your time. [import]uid: 74723 topic_id: 26215 reply_id: 326215[/import]

#2

Nil out the image variable after inserting it into the obj group. [import]uid: 9840 topic_id: 26215 reply_id: 106254[/import]

#3

Aside from that am i missing anything else? What happens if i didn’t set the image to nil? [import]uid: 74723 topic_id: 26215 reply_id: 106269[/import]

#4

Maybe a small memory leak. Once its in the group and not referenced its best to nil it out. [import]uid: 9840 topic_id: 26215 reply_id: 106302[/import]

#5

Since you are attaching an event listener to each object created, a small leak exists if you don’t remove them as well when you remove each object. See:

http://www.ludicroussoftware.com/blog/2011/08/24/remove-all-listeners/

I added these two lines after line 37 in main.lua:

 myObj.\_functionListeners = nil  
 myObj.\_tableListeners = nil

and got a small reduction in the memory left over. [import]uid: 23636 topic_id: 26215 reply_id: 106349[/import]

#6

Thanks guys, much appreciated [: Time to clean up some memory leaks! [import]uid: 74723 topic_id: 26215 reply_id: 106358[/import]