I am having a memory leak issue with the following code. As much as I can tell I don't see why the problem persists but it still does not release when called. I am detecting the problem in instruments and the following code is keeping its "cards" classes alive even when it should had released them.
Any help welcome.
...
...
-(id)initDeckWithCardsPicked: (NSMutableArray*)cardsPicked andColors:(NSMutableArray*)cardColors
{
self = [self init];
if (self != nil) {
int count = [cardsPicked count];
for (int i=0; i<count; i++) {
int cardNum = [[cardsPicked objectAtIndex:i] integerValue];
Card * card = [[MemoryCard alloc] initWithSerialNumber:cardNum position: CGPointZero color:[cardColors objectAtIndex:i]];
[_cards addObject: card];
[card release];
}
}
return self;
}
- (id) init
{
self = [super init];
if (self != nil) {
self.bounds = (CGRect){{0,0},[Card cardSize]};
self.cornerRadius = 8;
self.backgroundColor = kAlmostInvisibleWhiteColor;
self.borderColor = kHighlightColor;
self.cards = [NSMutableArray array];
}
return self;
}
...
...
Without looking at the rest of your code, its hard to know where the problem is, but have you tried using the static analyzer in xcode? Its can be invaluable for finding memory leaks.
To use it, select 'Build and Analyze' from the Build menu. Further details are on Apple's dev website.
When you add a Card to the _cards NSMutableArray using addObject, it is sent a retain message. Thus, as long as you keep _cards in memory, a pointer will also be kept for each of it's constituents. As long as your dealloc releases the array, or you do so elsewhere, you shoul dbe fine with what you have posted here (assuming your initWithSerialNumber method returns a retained object).
Related
I'm stumped trying to debug an issue on iOS that seems to only occur with Release builds which seems to implicate that the optimizer is doing something that isn't playing nicely with my code. The code that crashes is some code that is serializing some binary data into a NSMutableData instance as follows.
[_data increaseLengthBy:sizeof(CFSwappedFloat64)];
*((CFSwappedFloat64 *)[self pointerAtOffset]) = CFConvertFloat64HostToSwapped(value);
_offset += sizeof(CFSwappedFloat64);
_data is a NSMutableData instance. pointerAtOffset and the init method for this class is defined as follows.
- (unsigned char *)pointerAtOffset {
return ((unsigned char *)_data.mutableBytes) + _offset;
}
- (id)init {
if( self = [super init] ) {
_data = [[NSMutableData alloc] initWithCapacity:1028];
_offset = 0;
}
return self;
}
Now the strange thing is that if I add a NSLog print statement, it fixes the bug.
[_data increaseLengthBy:sizeof(CFSwappedFloat64)];
NSLog(#"%d - %d", (int)_data.mutableBytes, _offset);
*((CFSwappedFloat64 *)[self pointerAtOffset]) = CFConvertFloat64HostToSwapped(value);
_offset += sizeof(CFSwappedFloat64);
Any ideas what might be causing this? It's kind of unnerving to deploy code that works because of a NSLog statement.
This reminds me of the armv6 Thumb instruction problems. If you change your debug build settings to optimize to Fastest,Smallest and it crashes, then that is your problem.
fresh to objC and cocos2d :)
i'm following "learn cocos2d game development with iOS5", in chapter4, there is a "DoodleDrop" game.
define some variable in GameScene.h like this
#interface GameScene : CCLayer
{
CCSprite *player;
CGPoint playerVelocity;
CCArray *spiders;
CGSize screenSize;
int dropedSpidersCount;
float duration;
}
+ (CCScene *)scene;
#end
in GameScene.m the init method looks like this
- (id)init
{
if (self = [super init]) {
duration = 4.0;
[self createPlayer];
[self createSpiders]; // spiders were inited here.
[self resetSpiders];
[self schedule:#selector(chooseSpider:) interval:0.7];
}
return self;
}
while in chooseSpider, i cannot access spiders, xcode broke
in other methods, spiders or duration just behave normally, why does this happens?
gist code added
https://gist.github.com/2940466
After inspecting your code, I suggest you to try this fix:
- (void)createSpiders
{
CCSprite *tempSpider = [CCSprite spriteWithFile:#"spider.png"];
CGSize spiderSize = [tempSpider texture].contentSize;
int spiderCount = screenSize.width / spiderSize.width;
spiders = [[CCArray arrayWithCapacity:spiderCount] retain];
for (int i = 0; i < spiderCount; i++) {
CCSprite *spider = [CCSprite spriteWithFile:#"spider.png"];
[self addChild:spider];
[spiders addObject:spider];
}
}
where the only difference is in the line:
spiders = [[CCArray arrayWithCapacity:spiderCount] retain];
Indeed, if you do not retain you spiders object, it will be autoreleased at the next run loop iteration.
OLD ANSWER:
Without seeing more code it is not possible to say exactly what is happening, but it seems that in the interval between creating the spiders and the actual execution of chooseSpiders, your spiders array gets deallocated.
As a quick try, I would suggest adding:
[spiders retain];
before calling
[self schedule:#selector(chooseSpider:) interval:0.7];
and see wether the crash keeps happening.
if you provide more code, it could be possible to help you further.
is there any difference between the two methods?
```
// MACRO FUNCTION
#define SAFELY_RELEASE(__POINTER) { [__POINTER release]; __POINTER = nil; }
// C FUNCTION
void SAFELY_RELEASE(id __POINTER) {
[__POINTER release]; __POINTER = nil;
}
```
Yes. The function won't do what you expect it to, because the pointer will have been passed into it by value, rather than by reference.
Imagine this:
- (void)method {
id object = [[NSObject alloc] init];
SAFELY_RELEASE( object );
}
SAFELY_RELEASE gets object. It can send it messages, but setting it to nil will not change its value in method.
An equivalent function would be:
void SAFELY_RELEASE(id *__POINTER) {
[*__POINTER release]; *__POINTER = nil;
}
Then you'd use it by using:
SAFELY_RELEASE( &object );
The macro has another downside, though: Xcode's refactoring tools will probably not be able to change the parameter inside. For instance:
#interface Foo {
NSObject *var;
}
#implementation Foo
- (id)init {
if (( self = [super init] )) {
var = [[NSObject alloc] init];
}
return self;
}
- (void)dealloc {
SAFELY_RELEASE(var);
[super dealloc];
}
If you try to rename var using the refactor tool, you'll probably find that it won't be able to rename the var in dealloc.
Really, unless you have a really good reason to do this you should be using ARC.
void SAFELY_RELEASE(id __POINTER) is guaranted to __POINTER be an releasable object.
Both of them is wrong, because __POINTER = nil; will have no effects. You should nil it in object (controller)
I was using one of these macros, then I cam across this post.
Makes sense that you don't want to set to nil while in development as you want it to crash on a dealloc reference and not sending it to nil.
I have the following method in my app :
- (void) loadModel {
// Runs in a seperate thread so we need to create an additional NSAutoreleasePool
pool = [[NSAutoreleasePool alloc] init];
NSData *getData = [activeModelInfo getFileData];
if (getData) {
if ([activeModel loadFromFileData:daeData]) {
[activeModel reset];
[mainViewController performSelectorOnMainThread:#selector(showModelView) withObject:nil waitUntilDone:NO];
}
else {
}
}
else {
}
[pool release];
}
The loadFromFileData method calls the following code which loads data. :
- (void) loadVerticesFromSource:(NSString*)verticesSourceId meshNode:(TBXMLElement*)meshNode intoMesh: (Mesh3D*) mesh {
NSLog(#"Getting Vertices for Source %#",verticesSourceId);
FloatArray *floatArray = [self getFloatArrayFromSource: verticesSourceId meshNode: meshNode];
if (floatArray) {
[daeFloatArray addObject:floatArray];
}
if (floatArray) {
if ([floatArray.array count] % 3 != 0) {
NSLog(#"Float array length not divisible by 3!");
}
else {
mesh->verticesCount = [floatArray.array count] / 3;
mesh->vertices = malloc(sizeof(Vector3D) * mesh->verticesCount);
for (int i=0; i<mesh->verticesCount; i++) {
mesh->vertices[i].x = [[floatArray.array objectAtIndex:(i*3)] floatValue];
mesh->vertices[i].y = [[floatArray.array objectAtIndex:(i*3)+1] floatValue];
mesh->vertices[i].z = [[floatArray.array objectAtIndex:(i*3)+2] floatValue];
// update extents information
if (!extents.pointDefined || mesh->vertices[i].x < extents.minX) extents.minX = mesh->vertices[i].x;
else if (!extents.pointDefined || mesh->vertices[i].x > extents.maxX) extents.maxX = mesh->vertices[i].x;
if (!extents.pointDefined || mesh->vertices[i].y < extents.minY) extents.minY = mesh->vertices[i].y;
else if (!extents.pointDefined || mesh->vertices[i].y > extents.maxY) extents.maxY = mesh->vertices[i].y;
if (!extents.pointDefined || mesh->vertices[i].z < extents.minZ) extents.minZ = mesh->vertices[i].z;
else if (!extents.pointDefined || mesh->vertices[i].z > extents.maxZ) extents.maxZ = mesh->vertices[i].z;
if (!extents.pointDefined) extents.pointDefined = YES;
[pointerStorageArray addObject:[NSValue valueWithPointer:mesh->vertices]];
}
}
}
}
Since this method is called several times while the data loads, each time mallocing memory for the mesh->vertices struct, I have created a pointerStorage array where I store the pointer to the malloced memory.
The app then displays a 3D object using OpenGL ES. When the user presses a Main Menu button, I then free up the pointerStorageArray as follows :
- (void) freeUpMallocedMemory
for (NSValue * value in pointerStorageArray) {
free(value);
}
The problem is that the app then crashes during this process. All I get is the EXC_BAD_ACCESSS error message and a pointer to the following line of code in the loadModel method above :
[pool release];
Nothing in the stack trace. I have also tried turning on NSZombie, NSAutoreleaseTrackFreedObjectCheck and NSDebugEnabled, but I still don't get any additional information.
The odd thing is that if I put a delay on the button of 2 seconds (i.e only trigger the freeUpMallocedMemory method after 2 seconds), the app no longer crashes and works fine.
Can anyone suggest what might be causing this - really confused and have already spent a few days troubleshooting.
Thank you !
You are over-releasing... the values in pointerStorageArray are created via a convenience method and as such don't need releasing, simply removing them from the array will dispose of them.
I'm a beginner level programmer trying to make a game app for the iphone and I've encountered a possible issue with the memory management (exc_bad_access) of my program so far. I've searched and read dozens of articles regarding memory management (including apple's docs) but I still can't figure out what exactly is wrong with my codes. So I would really appreciate it if someone can help clear up the mess I made for myself.
//in the .h file
#property(nonatomic,retain) NSMutableArray *fencePoleArray;
#property(nonatomic,retain) NSMutableArray *fencePoleImageArray;
#property(nonatomic,retain) NSMutableArray *fenceImageArray;
//in the .m file
- (void)viewDidLoad {
[super viewDidLoad];
self.gameState = gameStatePaused;
fencePoleArray = [[NSMutableArray alloc] init];
fencePoleImageArray = [[NSMutableArray alloc] init];
fenceImageArray = [[NSMutableArray alloc] init];
mainField = CGRectMake(10, 35, 310, 340);
..........
[NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:#selector(gameLoop) userInfo:nil repeats:YES];
}
So basically, the player touches the screen to set up the fences/poles
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
if(.......) {
.......
}
else {
UITouch *touch = [[event allTouches] anyObject];
currentTapLoc = [touch locationInView:touch.view];
NSLog(#"%i, %i", (int)currentTapLoc.x, (int)currentTapLoc.y);
if(CGRectContainsPoint(mainField, currentTapLoc)) {
if([self checkFence]) {
onFencePole++;
//this 3 set functions adds their respective objects into the 3 NSMutableArrays using addObject:
[self setFencePole];
[self setFenceImage];
[self setFencePoleImage];
.......
}
}
else {
.......
}
}
}
}
The setFence function (setFenceImage and setFencePoleImage is similar to this)
-(void)setFencePole {
Fence *fencePole;
if (!elecFence) {
fencePole = [[Fence alloc] initFence:onFencePole fenceType:1 fencePos:currentTapLoc];
}
else {
fencePole = [[Fence alloc] initFence:onFencePole fenceType:2 fencePos:currentTapLoc];
}
[fencePoleArray addObject:fencePole];
[fencePole release];
and whenever I press a button in the game, endOpenState is called to clear away all the extra images(fence/poles) on the screen and also to remove all existing objects in the 3 NSMutableArray. Point is to remove all the objects in the NSMutableArrays but keep the array itself so it can be reused later.
-(void)endOpenState {
........
int xMax = [fencePoleArray count];
int yMax = [fenceImageArray count];
for (int x = 0; x < xMax; x++) {
[[fencePoleImageArray objectAtIndex:x] removeFromSuperview];
}
for (int y = 0; y < yMax; y++) {
[[fenceImageArray objectAtIndex:y] removeFromSuperview];
}
[fencePoleArray removeAllObjects];
[fencePoleImageArray removeAllObjects];
[fenceImageArray removeAllObjects];
........
}
The crash happens here at the checkFence function.
-(BOOL)checkFence {
if (onFencePole == 0) {
return YES;
}
else if (onFencePole >= 1 && onFencePole < currentMaxFencePole - 1) {
CGPoint tempPoint1 = currentTapLoc;
CGPoint tempPoint2 = [[fencePoleArray objectAtIndex:onFencePole-1] returnPos]; // the crash happens at this line
if ([self checkDistance:tempPoint1 point2:tempPoint2]) {
return YES;
}
else {
return NO;
}
}
else if (onFencePole == currentMaxFencePole - 1) {
......
}
else {
return NO;
}
}
So the problem here is, everything works fine until checkFence is called the 2nd time after endOpenState is called. So its like tap_screen -> tap_screen -> press_button_to_call_endOpenState -> tap screen -> tap_screen -> crash
What I'm thinking of is that fencePoleArray got messed up when I used [fencePoleArray removeAllObjects] because it doesn't crash when I comment it out. It would really be great if someone can explain to me what went wrong. And thanks in advance.
First, a couple of suggestions:
if (!elecFence) {
fencePole = [[Fence alloc] initFence:onFencePole
fenceType:1 fencePos:currentTapLoc];
}
else {
fencePole = [[Fence alloc] initFence:onFencePole
fenceType:2 fencePos:currentTapLoc];
}
You’re making this too hard, how about this:
const int fenceType = elecFence ? 2 : 1;
Fence *fencePole = [[Fence alloc] initFence:onFencePole
fenceType:fenceType fencePos:currentTapLoc];
And this:
int xMax = [fencePoleArray count];
int yMax = [fenceImageArray count];
for (int x = 0; x < xMax; x++) {
[[fencePoleImageArray objectAtIndex:x] removeFromSuperview];
}
for (int y = 0; y < yMax; y++) {
[[fenceImageArray objectAtIndex:y] removeFromSuperview];
}
Could be shortened using makeObjectsPerformSelector:
const SEL remove = #selector(removeFromSuperview);
[fencePoleImageArray makeObjectsPerformSelector:remove];
[fenceImageArray makeObjectsPerformSelector:remove];
This is shorter and safer, as the xMax bound in your code is computed from fencePoleArray and used to iterate over fencePoleImageArray. (Could be right, could be wrong.)
Now to the objectAtIndex: call. If the array is still in memory and you tried to access an object beyond the array bounds, you would get an exception. So that I guess that either the array or some of the objects in it got released without you knowing it. You could try to NSLog the array and the object on given index and try to log their retainCount. If the logging line crashes, you have found the object that’s been released and can start looking for the cause.
(And one more thing: You should split the game logic into a separate model class. This simplifies the code and makes it easier to reason about.)
If you want to use properties, you should use self.propertyName = ... instead of propertyName = ....
Hope this will help.