Potential leaks in iOS project - ios

Question

Hello i have this function, that gets dummy data from file in project:
Issues are shown in those lines:
NSString *path = [[NSBundle mainBundle] pathForResource: #"StatisticsDataJSON" ofType: #"TXT"]; - potential leak of an object.
NSMutableDictionary *statisticsResponse = [jsonParser objectWithString:data]; - potential leak of an object stored into 'jsonParser'
for (id key in statisticsResponse) { - potential leak of an object stored into 'statisticArray'
for (int i = 0; i < statsForDate.count; i++) { - potential leak of an object stored into 's'
if (self.statistics==nil)
{
self.statistics = [[NSMutableDictionary alloc]init];
NSString *path = [[NSBundle mainBundle] pathForResource: #"StatisticsDataJSON" ofType: #"TXT"];
NSError *error = nil;
NSString *data = [NSString stringWithContentsOfFile: path
encoding: NSUTF8StringEncoding
error: &error];
//NSLog(#"%#",data);
SBJsonParser *jsonParser = [[SBJsonParser alloc] init];
NSMutableDictionary *statisticsResponse = [jsonParser objectWithString:data];
for (id key in statisticsResponse) {
NSArray *statsForDate = [statisticsResponse objectForKey:key];
NSMutableArray *statisticArray = [[NSMutableArray alloc]init];
for (int i = 0; i < statsForDate.count; i++) {
Statistic *s = [[Statistic alloc]init];
s.locationId = [[statsForDate objectAtIndex:i] objectForKey:#"locationId"];
int value =[[[statsForDate objectAtIndex:i] objectForKey:#"visits"] integerValue];
s.visits = value;
value =[[[statsForDate objectAtIndex:i] objectForKey:#"totalUsers"] integerValue];
s.totalUsers = value;
value= [[[statsForDate objectAtIndex:i] objectForKey:#"uploads"] integerValue];
s.uploads = value;
value = [[[statsForDate objectAtIndex:i] objectForKey:#"downloads"] integerValue];
s.downloads = value;
value = [[[statsForDate objectAtIndex:i] objectForKey:#"apps"] integerValue];
s.apps = value;
[statisticArray addObject:s];
}
[self.statistics setObject:statisticArray forKey:key];
};
}
I have found that autorelease in ststisticsResponse - resolves the problem:
NSMutableDictionary *statisticsResponse = [[jsonParser objectWithString:data]autorelease];
But then something fails in SBJsonStreamParserAccumulator.m in dealoc function.
What is the problem?

Answer 1

Note that the warnings about potential leaks come on the line after the potential leak, because that's the first point at which the referenced object is technically "leaked". So your current fixes are probably over-releasing and causing crashes.
The first statement in your question actually refers to a leak in this line, immediately before:
self.statistics = [[NSMutableDictionary alloc]init];
You've got no further reference to that allocated dictionary, and it's a retained property, so you have a leak.
self.statistics = [[[NSMutableDictionary alloc]init] autorelease];
Will fix that one. The next one, you have to release the jsonParser when you've finished with it (after the parsing is done):
[jsonParser release];
I'm not going to go through all of them but you should get the idea. Basically you need to read the memory management guide, or update to ARC.
Pay attention to the variable names in the warnings. They tell you where the leak is.