Memory leak in [NSMutableArray arrayWithContentsOfFile:path]

phil1337 · 08-13-2010, 01:35 PM

Hello

I searched the forum for this problem but did not find any solution.

Accoring to "Apple's Instruments", the following code leads to a memory leak:

Code:

NSString *path = [[WinNavAppDelegate class] pathForDocumentWithName:@"file.plist"];
	BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:path];
	if (!fileExists) {
		NSData *fileContents = [@"" dataUsingEncoding:NSUTF8StringEncoding];
		[[NSFileManager defaultManager] createFileAtPath:path
												contents:fileContents
											  attributes:nil];
		
	}
	NSMutableArray *bookDicts = [NSMutableArray arrayWithContentsOfFile:path];
	
	if (bookDicts == nil)
	{
		path = nil;
		path = [[NSBundle mainBundle] pathForResource:@"file"
											   ofType:@"plist"];
		bookDicts = [NSMutableArray arrayWithContentsOfFile:path];
	}
	
	[_displayedObjects release];
	_displayedObjects = [[NSMutableArray alloc]
						 initWithCapacity:[bookDicts count]];
	
	for (NSDictionary *currDict in bookDicts)
	{
		Book *book = [[Book alloc] initWithDictionary:currDict];
		[_displayedObjects addObject:book];
		[book release];
	}

The line which causes the problem is

Code:

NSMutableArray *bookDicts = [NSMutableArray arrayWithContentsOfFile:path];

What am I doing wrong?

Can anyone help me out of this?

Thank you

Regards

Phil

Duncan C · 08-13-2010, 05:18 PM

Quote:

Originally Posted by phil1337

Hello

I searched the forum for this problem but did not find any solution.

Accoring to "Apple's Instruments", the following code leads to a memory leak:

Code:

NSString *path = [[WinNavAppDelegate class] pathForDocumentWithName:@"file.plist"];
	BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:path];
	if (!fileExists) {
		NSData *fileContents = [@"" dataUsingEncoding:NSUTF8StringEncoding];
		[[NSFileManager defaultManager] createFileAtPath:path
												contents:fileContents
											  attributes:nil];
		
	}
	NSMutableArray *bookDicts = [NSMutableArray arrayWithContentsOfFile:path];
	
	if (bookDicts == nil)
	{
		path = nil;
		path = [[NSBundle mainBundle] pathForResource:@"file"
											   ofType:@"plist"];
		bookDicts = [NSMutableArray arrayWithContentsOfFile:path];
	}
	
	[_displayedObjects release];
	_displayedObjects = [[NSMutableArray alloc]
						 initWithCapacity:[bookDicts count]];
	
	for (NSDictionary *currDict in bookDicts)
	{
		Book *book = [[Book alloc] initWithDictionary:currDict];
		[_displayedObjects addObject:book];
		[book release];
	}

The line which causes the problem is

Code:

NSMutableArray *bookDicts = [NSMutableArray arrayWithContentsOfFile:path];

What am I doing wrong?

Can anyone help me out of this?

Thank you

Regards

Phil

The leaks instrument points to the line where an object is created, not the line where the leak occurs. You need to go look at where it's retained. The code you reference returns an autoreleased object, so it will go away on it's own unless you retain it somewhere else.

phil1337 · 08-13-2010, 06:08 PM

Quote:

Originally Posted by Duncan C

The leaks instrument points to the line where an object is created, not the line where the leak occurs. You need to go look at where it's retained. The code you reference returns an autoreleased object, so it will go away on it's own unless you retain it somewhere else.

Thank you for your answer.

I also tried this:

Code:

NSArray *bookDicts = [[NSArray alloc] initWithContentsOfFile:path];
...
[bookDicts release];

This doesn't help either.

The "path" object is returned from a static method which looks like this:

Code:

+ (NSString *)pathForDocumentWithName:(NSString *)documentName
{
	NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
	NSString *documentsDirectory = [paths objectAtIndex:0];
	NSString *tempPath = [documentsDirectory stringByAppendingPathComponent:documentName];
	    
    return tempPath;
}

Is the method correct so far?

Thank you very much

Regards

Phil