NSOperation使用GCD，确保所有线程都在同一线程上 [英] NSOperation using GCD, ensure all on the same thread
问题描述
我有一个'concurrent'NSOperation，在它工作期间，它使用一些内部使用GCD的控制器类.当这些控制器类返回其完成块时，该完成块在另一个线程上.
I have a 'concurrent' NSOperation, and during it's work it uses some controller classes that internally use GCD. When these controller classes return with their completion block, the completion block is on another thread.
我知道我可以将当前线程存储在操作启动方法中并运行performSelectorOnThread:，但是理想情况下，我希望将完成内容包装在GCD块中，并分派到与操作开始时相同的线程上.使用GCD甚至可以做到这一点，因为我只能指定要分发的队列.
I know I could store the current thread in the operation start method and run performSelectorOnThread:, but ideally I would like to wrap the completion in a GCD block and dispatch onto the same thread as the operation started on. Is this even possible with GCD, as I can only specify a queue to dispatch to.
将这项工作恢复到操作开始所在的同一线程上的最佳方法是什么?除了我已经建议的以外，除非这是最好的方法.
What's the best way to bring this work back onto the same thread that the operation started on? Apart from what I already suggested... unless this is the best way.
推荐答案
我认为这真的不可能/不建议.从iOS 4开始，NSOperation使用GCD，并且随着GCD管理我的线程-我认为我不应该保留对它们的引用.
I don't think this is really possible/advisable. Since iOS 4 onwards, NSOperation is using GCD , and as GCD is managing my threads - I don't think I should be keeping references to them.
我确实找到了一些在特定线程上执行代码块的util方法.参见 Practical Blocks by Mike Ash 或本文做类似的事情.
I did find some util methods for executing blocks of code on a particular thread. See Practical Blocks by Mike Ash or this article doing similar thing.
因为我的目标是将核心数据调用保持在同一线程上，所以我选择升级代码以使用具有NSPrivateQueueConcurrencyType的父/子托管对象上下文，然后在托管对象上下文上使用performBlock:以确保所有核心数据正确执行了各个线程上的回调.
As my goal was to keep my core data calls on the same thread, instead I opted to upgrade my code to use parent/child managed object contexts with NSPrivateQueueConcurrencyType, and then used performBlock: on the managed object context to ensure all my call backs on the separate threads got executed correctly by core data.
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