xml解析期间的内存泄漏问题？

Question

我遇到了奇怪的内存泄漏问题，

现在我的代码是，

-(NSMutableDictionary *)getParsedWallpaperData{
NSMutableDictionary *dataDictionary = [NSMutableDictionary dictionary];

NSData *xmlData = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Wallpaper" ofType:@"xml"]];
TBXML *tbXml = [[TBXML alloc] initWithXMLData:xmlData error:nil];

//TBXML *tbXml = [[TBXML tbxmlWithXMLData:xmlData error:nil] autorelease];

@synchronized(self){
    TBXMLElement *rootXMLElement = tbXml.rootXMLElement;

    if(rootXMLElement)
    {
        TBXMLElement *paging = [TBXML childElementNamed:kPaging parentElement:rootXMLElement];
        NSMutableDictionary *pagingData = [[NSMutableDictionary alloc] init];
        if(paging){
            TBXMLElement *totalPages = [TBXML childElementNamed:kTotalPages parentElement:paging];
            NSString *totalPagesString = [TBXML textForElement:totalPages];
            [pagingData setObject:totalPagesString forKey:@"TotalPages"];

            TBXMLElement *currentPage = [TBXML childElementNamed:kCurrentPage parentElement:paging];
            NSString *currentPageString = [TBXML textForElement:currentPage];
            [pagingData setObject:currentPageString forKey:@"CurrentPage"];

            TBXMLElement *prevPage = [TBXML childElementNamed:kPerviousPage parentElement:paging];
            NSString *prevPageString = [TBXML textForElement:prevPage];
            [pagingData setObject:prevPageString forKey:@"PreviousPage"];

            TBXMLElement *nextPage = [TBXML childElementNamed:kNextPage parentElement:paging];
            NSString *nextPageString = [TBXML textForElement:nextPage];
            [pagingData setObject:nextPageString forKey:@"NextPage"];
        }
        [dataDictionary setObject:pagingData forKey:@"PagingInfo"];
        [pagingData release];
        pagingData = nil;

        TBXMLElement *totalItems = [TBXML childElementNamed:kTotalItems parentElement:rootXMLElement];
        NSString *totalItemsString = [TBXML textForElement:totalItems];
        [dataDictionary setObject:totalItemsString forKey:@"TotalItems"];

        NSMutableArray *itemArray = [[NSMutableArray alloc] initWithCapacity:[totalItemsString intValue]]; 

        TBXMLElement *items = [TBXML childElementNamed:kItems parentElement:rootXMLElement];
        if(items){
            TBXMLElement *item = [TBXML childElementNamed:kItem parentElement:items];
            while (item) {
                NSMutableDictionary *itemInfoDict = [[NSMutableDictionary alloc] init];
                TBXMLElement *title = [TBXML childElementNamed:kTitle parentElement:item];
                NSString *titleString = [TBXML textForElement:title];
                [itemInfoDict setObject:titleString forKey:@"Title"];

                TBXMLElement *image1 = [TBXML childElementNamed:kImage1 parentElement:item];
                NSString *image1String = [TBXML textForElement:image1];
                [itemInfoDict setObject:image1String forKey:@"Image1"];

                TBXMLElement *image2 = [TBXML childElementNamed:kImage2 parentElement:item];
                NSString *image2String = [TBXML textForElement:image2];
                [itemInfoDict setObject:image2String forKey:@"Image2"];

                TBXMLElement *image3 = [TBXML childElementNamed:kImage3 parentElement:item];
                NSString *image3String = [TBXML textForElement:image3];
                [itemInfoDict setObject:image3String forKey:@"Image3"];

                TBXMLElement *thumbnail = [TBXML childElementNamed:kThumbnail parentElement:item];
                NSString *thumbnailString = [TBXML textForElement:thumbnail];
                [itemInfoDict setObject:thumbnailString forKey:@"Thumbnail"];

                [itemArray addObject:itemInfoDict];
                [itemInfoDict release];
                itemInfoDict = nil;
                item = item -> nextSibling;
            }
        }
        [dataDictionary setObject:itemArray forKey:@"ImagesInfo"];
        [itemArray release];
        itemArray = nil;
    }
}

[tbXml release];
tbXml = nil; 
return dataDictionary;
 }

我发现只有内存泄漏 TBXML *tbXml = [[TBXML alloc] initWithXMLData:xmlData error:nil];在这条线上，即使我手动释放 tbXml 对象，

请告诉我这发生了什么？

谢谢，

Answer 1

好吧，如果它是显示为泄漏的根元素，我想知道是否有像 childElementNamed 这样的访问器之一导致它（通过返回类似于 NSString 但实际上也存储了优化指针的东西到根元素）。可以看看childElementNamed的实现吗？更改代码以确保它不是这样的相对快速的方法是使用[NSString stringWithFormat:@"%@", [TBXML textForElement:fooTitle]] 调用将要存储在dataDictionary 中的任何NSString 结果包装起来。

此外，如果 TBXML 正在创建大量自动释放对象，您可以将此函数包装在 @nsautoreleasepool 宏中。

作为最后的建议，如果可以的话，您应该查看 ARC（即，如果您要部署到 iOS 4+）。

Answer 2

在函数顶部添加这一行：

NSAutoreleasePool *Pool=[[NSAutoreleasePool alloc]init];

并在函数底部的“return”语句之前添加这一行：

[Pool drain];

希望这会对你有所帮助。