XML Parsing Class Leaking Strings on Rerun - objective-c

Question

I've been at this issue for two days, and no matter what I do, I cannot get it to stop leaking strings.
The class is a XML parser (using TouchXML), that is designed to run repeatedly throughout the life time of the application. The first time it runs, there are no leaks, everything cleans up perfectly. On the second run, it begins to leaks, almost always where ever strings are.
Some images from Instruments:
http://www.producerstudio.net/1.png
http://www.producerstudio.net/2.png
.h
#import <Foundation/Foundation.h>
#import "TouchXML.h"
#protocol RSSParsingComplete
-(void)parsingFinished;
#end
#interface RSS : NSObject<NSXMLParserDelegate>{
NSArray *rssURLArray;
NSMutableData *xmlData;
NSMutableArray *articles;
NSMutableArray *arrayOfArticles;
int numberOfFeeds;
NSDateFormatter *inputFormatter;
NSDateFormatter *outputFormatter;
id<RSSParsingComplete> delegate;
}
#property (nonatomic, retain) NSArray *rssURLArray;
#property (nonatomic, retain) NSMutableData *xmlData;
#property (nonatomic, retain) id<RSSParsingComplete> delegate;
#property (nonatomic, retain) NSMutableArray *articles;
#property (nonatomic, retain) NSMutableArray *arrayOfArticles;
#property (nonatomic, retain) NSDateFormatter *inputFormatter;
#property (nonatomic, retain) NSDateFormatter *outputFormatter;
-(id)initWithRSSArray:(NSArray *)inputURLArray;
-(void)connect;
-(NSArray *)feedArticles;
#end
.m
#import "RSS.h"
#implementation RSS
#synthesize xmlData, rssURLArray, articles, arrayOfArticles, delegate, inputFormatter, outputFormatter;
-(void)connect{
self.xmlData = [[[NSMutableData alloc] init] autorelease];
NSURL *rssURL = [[NSURL alloc] initWithString:[self.rssURLArray objectAtIndex:numberOfFeeds-1]];
NSURLConnection *urlConnection = [[NSURLConnection alloc] initWithRequest:[NSURLRequest requestWithURL:rssURL] delegate:self];
[urlConnection release];
[rssURL release];
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
[self.xmlData setLength:0];
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
[self.xmlData appendData:data];
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{
[xmlData release];
[connection release];
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection{
CXMLDocument *xmlDoc = [[[CXMLDocument alloc] initWithData:xmlData options:0 error:nil] autorelease];
self.articles = [[[NSMutableArray alloc] init] autorelease];
self.inputFormatter = [[[NSDateFormatter alloc] init] autorelease];
self.outputFormatter = [[[NSDateFormatter alloc] init] autorelease];
[self.inputFormatter setDateFormat:#"EEE, dd MMM yyyy HH:mm:ss zzz"];
[self.inputFormatter setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"] autorelease]];
[self.inputFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:#"UTC"]];
[self.outputFormatter setDateFormat:#"dd.MM.yyyy HH:mm:ss"];
[self.outputFormatter setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"] autorelease]];
[self.outputFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:#"UTC"]];
NSArray *itemNodes = [xmlDoc nodesForXPath:#"//item" error:nil];
for(CXMLElement *node in itemNodes){
NSMutableDictionary *article = [[NSMutableDictionary alloc] init];
for(int counter = 0; counter < [node childCount]; counter++){
if([[[node childAtIndex:counter] name] isEqualToString:#"title"]){
[article setObject:[[node childAtIndex:counter] stringValue] forKey:#"title"];
}
if([[[node childAtIndex:counter] name] isEqualToString:#"link"]){
[article setObject:[[node childAtIndex:counter] stringValue] forKey:#"url"];
}
if([[[node childAtIndex:counter] name] isEqualToString:#"description"]){
[article setObject:[[node childAtIndex:counter] stringValue] forKey:#"description"];
}
if([[[node childAtIndex:counter] name] isEqualToString:#"pubDate"]){
NSDate *tempDate = [self.inputFormatter dateFromString:[[node childAtIndex:counter] stringValue]];
[article setObject:[self.outputFormatter stringFromDate:tempDate] forKey:#"name"];
}
}
[self.articles addObject:article];
[article release];
}
NSArray *feedTitleNode = [xmlDoc nodesForXPath:#"//title" error:nil];
NSString *feedTitle = [[NSString alloc] initWithString:[[[feedTitleNode objectAtIndex:0] childAtIndex:0] stringValue]];
[self.articles addObject:feedTitle];
[feedTitle release];
[self.arrayOfArticles addObject:[articles copy]];
[self.articles removeAllObjects];
[inputFormatter release];
[outputFormatter release];
numberOfFeeds--;
if(numberOfFeeds > 0){
[self connect];
}else{
[delegate parsingFinished];
}
}
-(NSArray *)feedArticles{
NSLog(#"Array of Articles: %#", self.arrayOfArticles);
return self.arrayOfArticles;
}
-(id)initWithRSSArray:(NSArray *)inputURLArray{
self = [super init];
if (self) {
self.arrayOfArticles = [[[NSMutableArray alloc] init] autorelease];
self.rssURLArray = [[[NSArray alloc] initWithArray:inputURLArray] autorelease];
numberOfFeeds = [self.rssURLArray count];
[self connect];
}
return self;
}
-(void)dealloc{
[rssURLArray release];
[xmlData release];
[articles release];
[arrayOfArticles release];
[super dealloc];
}
- (id)init
{
self = [super init];
return self;
}
#end
I've done everything I can think of to resolve the leaks. I've read the Apple Memory Management guides, as well as the excellent guide on iPhoneDevSDK and that has helped me cut down on 90% of the leaks I originally had (the class doesn't leak so long as you call it once). Maybe i've been staring at this for too long, or maybe i'm missing something obvious.
I appreciate it!

Answer 1

First, should delegate be retained? I'm not sure why you need it as an instance variable at all. But since it's retained (and you don't seem to release it), your RSS object will retain a circular reference to itself and won't ever be released.
Second, do you need to keep the date formatters in an instance variable? It looks like you're allocating them and releasing them in the same method. Note that they're retained in the RSS instance and never released.