从NSJSONSerialization处理Foundation Object时发生内存泄漏

debugcn 发表于 Dev

戴维·P

我正在努力解决我做的辅助函数中的内存泄漏。辅助函数的结果为

+ (id)JSONObjectWithData:(NSData *)data options:(NSJSONReadingOptions)opt error:(NSError * _Nullable *)error

并将所有叶子元素转换为NSString（如果它们是NSNumbers）。

方法如下：

-(NSArray *) stringisizeObjects:(NSArray *)inputArray{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSMutableArray *mutable = [[NSMutableArray alloc] initWithCapacity:[inputArray count]];

    for (int i = 0; i < [inputArray count]; i++) {
        NSArray *keys = [inputArray[i] allKeys];

        NSMutableDictionary *addDictionary = [[NSMutableDictionary alloc] initWithCapacity:[keys count]];

        for (int j = 0; j < [keys count]; j++) {

            id theObject = [[inputArray[i] objectForKey:keys[j]]autorelease];

            if ([theObject isKindOfClass:[NSNumber class]]) {

                [addDictionary setObject:[theObject stringValue] forKey:keys[j]];
                [theObject release];

            }else if ([theObject isKindOfClass:[NSString class]]){
                [addDictionary setObject:[inputArray[i] objectForKey:keys[j]] forKey:keys[j]];
            }

        }
        [mutable addObject:addDictionary];
    }
    NSArray *returnArray = [mutable copy];

    [mutable removeAllObjects];
    [mutable release];
    [pool drain];
    return returnArray;
}

这是我获取输入数组的方法。

id parsedThingy = [NSJSONSerialization JSONObjectWithData:resultJSONData options:1 error:&jsonDecodeError];

在将结果传递给stringisize方法之前，必须确保我拥有一个带有匹配键的NSDictionaries NSArray。

NSArray *resultArray = [self stringisizeObjects:parsedThingy];

X代码内存泄漏工具已将我指出此方法是导致问题的原因。

仪器显示泄漏

如您所见，我已经尝试将内容包装在自动释放池中，自动释放和释放。我只是在这里看不到任何前进的方向。

这是一个运行24/7的非ARC项目。

编辑：我接受了Droppy的建议，并尝试使用mutableCopy重新编写该方法。泄漏仍然存在。在这一点上，我唯一的解决方法可能是将JSON的源更改为仅发送字符串。:(

-(NSArray *) stringisizeObjects2:(NSArray *)inputArray{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSMutableArray *mutableArray = [inputArray mutableCopy];

    for (int i = 0; i < [mutableArray count]; i++) {
        NSMutableDictionary *mutableDict = [mutableArray[i] mutableCopy];
        NSArray *keys = [mutableDict allKeys];

        for (int j = 0; j < [keys count]; j++) {
            if ([[mutableDict objectForKey:keys[j]] isKindOfClass:[NSNumber class]]) {
                NSString *stringValue = [[mutableDict objectForKey:keys[j]] stringValue];

                [mutableDict removeObjectForKey:keys[j]];
                [mutableDict setObject:stringValue  forKey:keys[j]];
            }
        }
        mutableArray[i] = [mutableDict copy];
        [mutableDict release];
    }

    NSArray *returnArray = [mutableArray copy];

    [mutableArray release];
    [pool drain];
    return returnArray;
}

幼虫

问题：

addDictionary致电alloc但未致电release或autorelease
returnArray = [可变副本]; //确实增加了retainCount +1，需要autorelease在这里
id theObject = [inputArray[i] objectForKey:keys[j]]; //不需要自动释放或释放您不拥有的对象
将NSAutoreleasePool添加到此处的顶部只是什么都不做

解决方案：

-(NSArray *) stringisizeObjects:(NSArray *)inputArray{
    NSMutableArray *mutable = [[NSMutableArray alloc] initWithCapacity:[inputArray count]];

    for (int i = 0; i < [inputArray count]; i++) {
        NSArray *keys = [inputArray[i] allKeys];

        NSMutableDictionary *addDictionary = [[NSMutableDictionary alloc] initWithCapacity:[keys count]];

        for (int j = 0; j < [keys count]; j++) {

            id theObject = [inputArray[i] objectForKey:keys[j]]; // not need autorelease

            if ([theObject isKindOfClass:[NSNumber class]]) {

                [addDictionary setObject:[theObject stringValue] forKey:keys[j]];
                //[theObject release]; // not need release value here

            }else if ([theObject isKindOfClass:[NSString class]]){
                [addDictionary setObject:[inputArray[i] objectForKey:keys[j]] forKey:keys[j]];
            }

        }
        [mutable addObject:addDictionary];
        [addDictionary release]; // release after not use
    }
    NSArray *returnArray = [[[NSArray alloc] initWithArray:mutable] autorelease]; // auto release for return value

    [mutable removeAllObjects];
    [mutable release];
    return returnArray;
}

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