Question

我注意到@autoreleasepool的一个非常奇怪的行为。

我有一个这个方法，主线程上的计时器每隔“n”秒调用一次。该方法 - 简单地说 - 创建一个大型NSDictionary的副本并将其保存到给定路径的plist中。

所以，问题是在每次调用[snapshot writeToFile:pathname atomically:YES];之后，我的应用程序的内存占用量增加了大约5-6 MB，即使在退出@autorelease块之后也不会减少。

我无法理解问题是GCD，@ autoreleasepool，还是writeToFileName：atomically：，或者try / catch或者我是否犯了一些错误......

......我疯了。

有什么建议吗？

提前谢谢

罗布

-(void)serializeIndexDictionary
{
    if (_indexDictionary != nil && _needsToSerialize == YES)
    {
        // save index dictionary
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
            @autoreleasepool
            {
                @try
                {
                    NSDate *start = [NSDate date];
                    NSString *pathname = [NSString stringWithFormat:@"%@/%@", _cacheBasePath, _cacheFilename];
                    // Per fare una copia ci mette zero-virgola mentre per salvare su file ci mette qualche secondo...
                    // In questo modo la sezione critica dura molto meno...
                    // ...e considerato che l'accesso all'indice blocca qualunque operazione, non mi pare cosa da poco.
                    NSDictionary *snapshot = nil;
                    @synchronized (self)
                    {
                        snapshot = [_indexDictionary copy];
                        _needsToSerialize = NO;
                    }
                    /*
                     * If flag is YES, the dictionary is written to an auxiliary file, and then the auxiliary file is renamed to path. 
                     * If flag is NO, the dictionary is written directly to path. The YES option guarantees that path, if it exists at all, 
                     * --> won’t be corrupted even if the system should crash during writing. <--
                     */
                    [snapshot writeToFile:pathname atomically:YES];
                    snapshot = nil;
                    NSFileManager *fileManager = [NSFileManager defaultManager];
                    [fileManager addSkipBackupAttributeToItemAtPath:pathname];
                    NSDictionary *attributes = [fileManager attributesOfItemAtPath:pathname error:nil];
                    unsigned long long fileSize = [attributes fileSize];
                    NSLog(@"%@: Index serialized (%lld bytes in %g seconds)", self, fileSize, [[NSDate date] timeIntervalSinceDate:start]);
                }
                @catch (NSException *exception)
                {
                    NSString *message = [NSString stringWithFormat:@"%@: EXCEPTION CAUGHT\nDebug info:\n%@ (%@) [userInfo=%@]\n\nStack trace:\n%@",
                                         NSStringFromSelector(_cmd), exception.name, exception.reason, exception.userInfo, [exception callStackSymbols]];
                    NSLog(@"%@", message);
                }
                @finally
                {
                    // noop
                }
            }
        });
    }
}

@autoreleasepool似乎无法正常工作

0 个答案: