Question

I am using TouchXML to parse XML. While i am running the same in “Profile” Mode. I can able to see the memory leak. How can I fix this issue?

-(NSMutableArray *) grabXML:(NSData *)xmlData andQuery:(NSString *)query {  
    NSMutableArray *blogEntries = [[[NSMutableArray alloc] init] autorelease];  
    CXMLDocument *rssParser = [[[CXMLDocument alloc] initWithData:xmlData options:0 error:nil] autorelease];
    NSArray *resultNodes = [rssParser nodesForXPath:query error:nil];
    for (CXMLElement *resultElement in resultNodes) {
        NSMutableDictionary *blogItem = [[NSMutableDictionary alloc] init];
        int counter;
        for(counter = 0; counter < [resultElement childCount]; counter++) {
            [blogItem setObject:[[resultElement childAtIndex:counter] stringValue] forKey:[[resultElement childAtIndex:counter] name]];
        }
        for( int i = 0; i < [[resultElement attributes] count]; i++) {
            CXMLNode *node = [[resultElement attributes] objectAtIndex:i];
            [blogItem setObject:[[resultElement attributeForName:[node name]] stringValue] forKey:[node name]];
        }
        [blogEntries addObject:[blogItem copy]];
        [blogItem release];
    }
    return [blogEntries copy];
}

I am calling the above method in the below mentioned format.

NSMutableArray *arr = [[self grabXML:responseData andQuery:@"//wsCheneliereResult"] autorelease];

Answer 1

[blogEntries addObject:[blogItem copy]];

Here is your mistake : you do not need to copy the blogItem, addObject: will actually retain its argument so that you can safely call [blogItem release]; afterward.

And you most probably should not do return [blogEntries copy] either, and return just blogEntries : this is common programming habit that methods whose name does not contain ‘copy’ or ‘create’ return autoreleased values, such as you do not need to release them when you are done with them.

To sum up, I would go with :

-(NSMutableArray *) grabXML:(NSData *)xmlData andQuery:(NSString *)query {  
    NSMutableArray *blogEntries = [[[NSMutableArray alloc] init] autorelease];  
    CXMLDocument *rssParser = [[[CXMLDocument alloc] initWithData:xmlData options:0 error:nil] autorelease];
    NSArray *resultNodes = [rssParser nodesForXPath:query error:nil];
    for (CXMLElement *resultElement in resultNodes) {
        NSMutableDictionary *blogItem = [[NSMutableDictionary alloc] init];
        int counter;
        for(counter = 0; counter < [resultElement childCount]; counter++) {
            [blogItem setObject:[[resultElement childAtIndex:counter] stringValue] forKey:[[resultElement childAtIndex:counter] name]];
        }
        for( int i = 0; i < [[resultElement attributes] count]; i++) {
            CXMLNode *node = [[resultElement attributes] objectAtIndex:i];
            [blogItem setObject:[[resultElement attributeForName:[node name]] stringValue] forKey:[node name]];
        }
        [blogEntries addObject:blogItem];
        [blogItem release];
    }
    return blogEntries;
}

and

NSMutableArray *arr = [self grabXML:responseData andQuery:@"//wsCheneliereResult"];