objective-c - XML 解析类在重新运行时泄漏字符串

Question

我已经处理这个问题两天了，无论我做什么，我都无法让它停止泄漏字符串。

该类是一个 XML 解析器(使用 TouchXML)，旨在在应用程序的整个生命周期内重复运行。第一次运行时，没有泄漏，一切都完美清理。在第二次运行时，它开始泄漏，几乎总是在字符串所在的位置。

Instruments 中的一些图片:

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

我已尽我所能解决泄漏问题。我已经阅读了 Apple 内存管理指南，以及关于 iPhoneDevSDK 的优秀指南，这帮助我减少了 90% 的泄漏(只要调用一次，该类就不会泄漏)。也许我已经盯着这个看太久了，或者我错过了一些明显的东西。

我很感激!

Answer 1

首先，是否应该保留delegate？我不确定你为什么需要它作为实例变量。但是由于它被保留了(而且您似乎没有释放它)，您的 RSS 对象将保留对其自身的循环引用并且永远不会被释放。

其次，您是否需要将日期格式化程序保存在一个实例变量中？看起来您正在以相同的方法分配和释放它们。请注意，它们保留在 RSS 实例中并且永远不会释放。