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我在这里坐了至少半个小时才发现我的代码中存在内存泄漏。我刚刚使用 NSOperationQueue 用异步方法替换了对（触摸）方法的同步调用。在我对代码进行更改后，Leak Inspector 报告了内存泄漏。使用 NSOperationQueue 的版本有什么问题？

没有 MemoryLeak 的版本

-(NSData *)dataForKey:(NSString*)ressourceId_
{
   NSString *cacheKey = [self cacheKeyForRessource:ressourceId_]; // returns an autoreleased NSString*
   NSString *path = [self cachePathForKey:cacheKey]; // returns an autoreleased NSString*

   NSData *data = [[self memoryCache] objectForKey:cacheKey];
   if (!data)
   {
      data = [self loadData:path]; // returns an autoreleased NSData* 
      if (data)
      {
         [[self memoryCache] setObject:data forKey:cacheKey];
      }
   }
   [[self touch:path];
   return data;
}

带有 MemoryLeak 的版本（我没有看到任何内容）

-(NSData *)dataForKey:(NSString*)ressourceId_
{
   NSString *cacheKey = [self cacheKeyForRessource:ressourceId_]; // returns an autoreleased NSString*
   NSString *path = [self cachePathForKey:cacheKey]; // returns an autoreleased NSString*

   NSData *data = [[self memoryCache] objectForKey:cacheKey];
   if (!data)
   {
      data = [self loadData:path]; // returns an autoreleased NSData* 
      if (data)
      {
         [[self memoryCache] setObject:data forKey:cacheKey];
      }
   }
   NSInvocationOperation *touchOp = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(touch:) object:path];
   [[self operationQueue] addOperation:touchOp];
   [touchOp release];
   return data;
}

当然，触摸方法也没有什么特别之处。只需更改文件的日期。

-(void)touch:(id)path_
{
   NSString *path = (NSString *)path_;
   NSFileManager *fm = [NSFileManager defaultManager];
   if ([fm fileExistsAtPath:path])
   {
      NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:[NSDate date], NSFileModificationDate, nil];
      [fm setAttributes: attributes ofItemAtPath:path error:nil];
   }
}
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