从 Utility Dispatch Queue 使用 PhotoKit 的问题
Problems Using PhotoKit from Utility Dispatch Queue
我正在尝试在我的应用程序在前台运行时对资产进行后台处理，但我一直遇到主线程性能不佳和优先级反转问题。我正在使用后台 QOS_UTILITY dispatch_async 调用。似乎即使我这样做了，最终它还是在调用 requestImageDataForAsset 期间回调到主线程。
看起来与底层 PhotoKit 库中的核心数据有关。看下面的主线程，所有的工作都应该在后台完成。每个调用 "Photos." 的地方我都在实用程序线程上放入了 dispatch_async。注意线程如何从 QOS.UTILITY 反弹到 QOS.DEFAULT 然后到主队列。
在 requestImageDataForAsset 的回调中，在做了下面的清单之后，我把它放回了回调中所需的队列（第 19 行），但是 UI 性能仍然不好，因为主线程正在做太多的工作或等待。这是我最好的选择还是我可以做些什么来让 photokit 在我的后台线程上进行处理？
Thread 1 Queue : com.apple.NSURLSession-work (serial)
#0 0x0000000198b1ceb8 in semaphore_wait_trap ()
#1 0x0000000100a53214 in _dispatch_semaphore_wait_slow ()
#2 0x00000001876940b0 in -[__NSURLBackgroundSession _onqueue_uploadTaskForRequest:uploadFile:bodyData:completion:] ()
#3 0x0000000187693cd8 in __80-[__NSURLBackgroundSession uploadTaskForRequest:uploadFile:bodyData:completion:]_block_invoke ()
#4 0x00000001876932fc in __68-[__NSURLBackgroundSession performBlockOnQueueAndRethrowExceptions:]_block_invoke ()
#5 0x0000000100a44df0 in _dispatch_client_callout ()
#6 0x0000000100a4e5f4 in _dispatch_barrier_sync_f_slow ()
#7 0x0000000187693280 in -[__NSURLBackgroundSession performBlockOnQueueAndRethrowExceptions:] ()
#8 0x0000000187693c68 in -[__NSURLBackgroundSession uploadTaskForRequest:uploadFile:bodyData:completion:] ()
#9 0x00000001000f5c1c in Photos.UploadDevice.(sendUploadWithUrl in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadDevice)(ObjectiveC.NSURL, localFileUrl : ObjectiveC.NSURL) -> Swift.Bool at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:346
#10 0x00000001000f4c08 in Photos.UploadDevice.(upload in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadDevice)(Swift.String, fileName : Swift.String, baseUrl : Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURL>) -> Swift.Bool at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:330
#11 0x00000001000fa1e0 in Photos.UploadDevice.(uploadFile in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadDevice)(Swift.String, size : Swift.Int64) -> () at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:537
#12 0x00000001001136ec in Photos.UploadManager.((exportAsset in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadManager) -> (ObjectiveC.PHAsset, name : Swift.String, device : Photos.UploadDevice) -> ()).(closure #1).(closure #2) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:770
#13 0x0000000100108b24 in partial apply forwarder for Photos.UploadManager.((exportAsset in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadManager) -> (ObjectiveC.PHAsset, name : Swift.String, device : Photos.UploadDevice) -> ()).(closure #1).(closure #2) ()
#14 0x0000000100113b54 in reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) to @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<Swift.String>, C.UIImageOrientation, Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>)) -> (@out ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:757
#15 0x0000000100108ba8 in partial apply forwarder for reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) to @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<Swift.String>, C.UIImageOrientation, Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>)) -> (@out ()) ()
#16 0x0000000100113ba4 in reabstraction thunk helper from @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<Swift.String>, C.UIImageOrientation, Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>)) -> (@out ()) to @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:757
#17 0x0000000100108c60 in partial apply forwarder for reabstraction thunk helper from @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<Swift.String>, C.UIImageOrientation, Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>)) -> (@out ()) to @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) ()
#18 0x0000000100113f3c in reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) to @callee_unowned @objc_block (@unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSString>, @unowned C.UIImageOrientation, @unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSDictionary>) -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:757
#19 0x000000018bad7380 in __65-[PHImageManager requestImageDataForAsset:options:resultHandler:]_block_invoke1437 ()
#20 0x0000000100a44e30 in _dispatch_call_block_and_release ()
#21 0x0000000100a44df0 in _dispatch_client_callout ()
#22 0x0000000100a4975c in _dispatch_main_queue_callback_4CF ()
#23 0x0000000187c5dfa4 in __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ ()
#24 0x0000000187c5c04c in __CFRunLoopRun ()
#25 0x0000000187b890a4 in CFRunLoopRunSpecific ()
#26 0x0000000190d335a4 in GSEventRunModal ()
#27 0x000000018c4be3c0 in UIApplicationMain ()
#28 0x0000000100118e58 in main at /Users/possen/projects/wdp/App/main.m:14
#29 0x0000000198a1ea08 in start ()
Enqueued from com.apple.root.default-qos (Thread 19)Queue : com.apple.root.default-qos (concurrent)
#0 0x0000000100a4dc38 in _dispatch_barrier_async_f ()
#1 0x000000018bac8df0 in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke729 ()
#2 0x0000000100a44e30 in _dispatch_call_block_and_release ()
#3 0x0000000100a44df0 in _dispatch_client_callout ()
#4 0x0000000100a519a0 in _dispatch_root_queue_drain ()
#5 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#6 0x0000000198bd12e4 in _pthread_wqthread ()
#7 0x0000000198bd0fa8 in start_wqthread ()
Enqueued from NSManagedObjectContext 0x15fd29310 (Thread 19)Queue : NSManagedObjectContext 0x15fd29310 (serial)
#0 0x0000000100a4655c in dispatch_async ()
#1 0x000000018baca94c in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke_2808 ()
#2 0x000000018bacad60 in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke_2813 ()
#3 0x000000018bac499c in __226-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesPossiblyThruAssetsdAndCPLWithRequest:library:format:optimalSourcePixelSize:wantsProperties:networkAccessAllowed:networkAccessForced:trackCPLDownload:sync:completionHandler:]_block_invoke ()
#4 0x000000018bac45d0 in -[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesPossiblyThruAssetsdAndCPLWithRequest:library:format:optimalSourcePixelSize:wantsProperties:networkAccessAllowed:networkAccessForced:trackCPLDownload:sync:completionHandler:] ()
#5 0x000000018bacaa8c in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke812 ()
#6 0x000000019291b2b0 in __82-[PLPhotoLibrary _withDispatchGroup:synchronously:performBlock:completionHandler:]_block_invoke ()
#7 0x00000001879f9270 in developerSubmittedBlockToNSManagedObjectContextPerform ()
#8 0x0000000100a44df0 in _dispatch_client_callout ()
#9 0x0000000100a4f854 in _dispatch_queue_drain ()
#10 0x0000000100a48120 in _dispatch_queue_invoke ()
#11 0x0000000100a5175c in _dispatch_root_queue_drain ()
#12 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#13 0x0000000198bd12e4 in _pthread_wqthread ()
#14 0x0000000198bd0fa8 in start_wqthread ()
Enqueued from com.apple.root.default-qos (Thread 25)Queue : com.apple.root.default-qos (concurrent)
#0 0x0000000100a4dc38 in _dispatch_barrier_async_f ()
#1 0x000000019291b278 in -[PLPhotoLibrary _withDispatchGroup:synchronously:performBlock:completionHandler:] ()
#2 0x000000018baca8cc in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke807 ()
#3 0x0000000100a4da28 in _dispatch_block_async_invoke_and_release ()
#4 0x0000000100a44df0 in _dispatch_client_callout ()
#5 0x0000000100a519a0 in _dispatch_root_queue_drain ()
#6 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#7 0x0000000198bd12e4 in _pthread_wqthread ()
#8 0x0000000198bd0fa8 in start_wqthread ()
Enqueued from com.apple.root.utility-qos (Thread 24)Queue : com.apple.root.utility-qos (concurrent)
#0 0x0000000100a52b7c in _dispatch_async_f_slow ()
#1 0x000000018bac6e7c in -[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:] ()
#2 0x000000018bacf618 in -[PHCoreImageManager _processImageRequest:sync:] ()
#3 0x000000018bad3214 in -[PHImageManager requestAsynchronousImageForAsset:chainedToMasterRequest:targetSize:contentMode:options:resultHandler:] ()
#4 0x000000018bad3048 in -[PHImageManager requestAsynchronousImageForAsset:targetSize:contentMode:options:resultHandler:] ()
#5 0x000000018bad6ec4 in -[PHImageManager requestImageDataForAsset:options:resultHandler:] ()
#6 0x0000000100111cc4 in Photos.UploadManager.((exportAsset in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadManager) -> (ObjectiveC.PHAsset, name : Swift.String, device : Photos.UploadDevice) -> ()).(closure #1) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:755
#7 0x000000010009d958 in reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_unowned @objc_block () -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/CameraRollController.swift:50
#8 0x0000000100a44e30 in _dispatch_call_block_and_release ()
#9 0x0000000100a44df0 in _dispatch_client_callout ()
#10 0x0000000100a519a0 in _dispatch_root_queue_drain ()
#11 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#12 0x0000000198bd12e4 in _pthread_wqthread ()
#13 0x0000000198bd0fa8 in start_wqthread ()
Enqueued from NSOperationQueue 0x170434820 :: NSOperation 0x1742564d0 (Thread 17)Queue : NSOperationQueue 0x170434820 :: NSOperation 0x1742564d0 (serial)
#0 0x0000000100a52b7c in _dispatch_async_f_slow ()
#1 0x0000000100102ddc in Photos.UploadManager.(exportAsset in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadManager)(ObjectiveC.PHAsset, name : Swift.String, device : Photos.UploadDevice) -> () at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:739
#2 0x000000010010fc2c in Photos.UploadDevice.((processAssets in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadDevice) -> () -> ()).(closure #1).(closure #1) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:507
#3 0x000000010010ca70 in Photos.UploadDevice.(fetchRemoteDirList (Photos.UploadDevice) -> (ObjectiveC.NSURL, block : (Swift.Optional<Swift.Dictionary<Swift.String, Photos.FileEntry>>, Swift.Optional<ObjectiveC.NSError>) -> ()) -> ()).(closure #2) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:284
#4 0x000000010010b198 in reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) to @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>)) -> (@out ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:236
#5 0x00000001000f3aec in partial apply forwarder for reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) to @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>)) -> (@out ()) with unmangled suffix "52" ()
#6 0x000000010010b3ec in reabstraction thunk helper from @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>)) -> (@out ()) to @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:236
#7 0x000000010010b444 in reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) to @callee_unowned @objc_block (@unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:236
#8 0x000000018763b2d4 in __49-[__NSCFLocalSessionTask _task_onqueue_didFinish]_block_invoke ()
#9 0x0000000188b5f508 in __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ ()
#10 0x0000000188ab0c94 in -[NSBlockOperation main] ()
#11 0x0000000188aa061c in -[__NSOperationInternal _start:] ()
#12 0x0000000188b6226c in __NSOQSchedule_f ()
#13 0x0000000100a44df0 in _dispatch_client_callout ()
#14 0x0000000100a4f854 in _dispatch_queue_drain ()
#15 0x0000000100a48120 in _dispatch_queue_invoke ()
#16 0x0000000100a5175c in _dispatch_root_queue_drain ()
#17 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#18 0x0000000198bd12e4 in _pthread_wqthread ()
#19 0x0000000198bd0fa8 in start_wqthread ()
我以某种方式误解了 PHImageRequestOptions 对象上的同步标志。将此设置为 true 将在发出图像请求的同一线程上调用它，这正是我想要的。关闭它后，它将响应发送到另一个导致问题出现的线程。
我正在尝试在我的应用程序在前台运行时对资产进行后台处理，但我一直遇到主线程性能不佳和优先级反转问题。我正在使用后台 QOS_UTILITY dispatch_async 调用。似乎即使我这样做了，最终它还是在调用 requestImageDataForAsset 期间回调到主线程。
看起来与底层 PhotoKit 库中的核心数据有关。看下面的主线程，所有的工作都应该在后台完成。每个调用 "Photos." 的地方我都在实用程序线程上放入了 dispatch_async。注意线程如何从 QOS.UTILITY 反弹到 QOS.DEFAULT 然后到主队列。
在 requestImageDataForAsset 的回调中，在做了下面的清单之后，我把它放回了回调中所需的队列（第 19 行），但是 UI 性能仍然不好，因为主线程正在做太多的工作或等待。这是我最好的选择还是我可以做些什么来让 photokit 在我的后台线程上进行处理？
Thread 1 Queue : com.apple.NSURLSession-work (serial)
#0 0x0000000198b1ceb8 in semaphore_wait_trap ()
#1 0x0000000100a53214 in _dispatch_semaphore_wait_slow ()
#2 0x00000001876940b0 in -[__NSURLBackgroundSession _onqueue_uploadTaskForRequest:uploadFile:bodyData:completion:] ()
#3 0x0000000187693cd8 in __80-[__NSURLBackgroundSession uploadTaskForRequest:uploadFile:bodyData:completion:]_block_invoke ()
#4 0x00000001876932fc in __68-[__NSURLBackgroundSession performBlockOnQueueAndRethrowExceptions:]_block_invoke ()
#5 0x0000000100a44df0 in _dispatch_client_callout ()
#6 0x0000000100a4e5f4 in _dispatch_barrier_sync_f_slow ()
#7 0x0000000187693280 in -[__NSURLBackgroundSession performBlockOnQueueAndRethrowExceptions:] ()
#8 0x0000000187693c68 in -[__NSURLBackgroundSession uploadTaskForRequest:uploadFile:bodyData:completion:] ()
#9 0x00000001000f5c1c in Photos.UploadDevice.(sendUploadWithUrl in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadDevice)(ObjectiveC.NSURL, localFileUrl : ObjectiveC.NSURL) -> Swift.Bool at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:346
#10 0x00000001000f4c08 in Photos.UploadDevice.(upload in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadDevice)(Swift.String, fileName : Swift.String, baseUrl : Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURL>) -> Swift.Bool at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:330
#11 0x00000001000fa1e0 in Photos.UploadDevice.(uploadFile in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadDevice)(Swift.String, size : Swift.Int64) -> () at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:537
#12 0x00000001001136ec in Photos.UploadManager.((exportAsset in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadManager) -> (ObjectiveC.PHAsset, name : Swift.String, device : Photos.UploadDevice) -> ()).(closure #1).(closure #2) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:770
#13 0x0000000100108b24 in partial apply forwarder for Photos.UploadManager.((exportAsset in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadManager) -> (ObjectiveC.PHAsset, name : Swift.String, device : Photos.UploadDevice) -> ()).(closure #1).(closure #2) ()
#14 0x0000000100113b54 in reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) to @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<Swift.String>, C.UIImageOrientation, Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>)) -> (@out ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:757
#15 0x0000000100108ba8 in partial apply forwarder for reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) to @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<Swift.String>, C.UIImageOrientation, Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>)) -> (@out ()) ()
#16 0x0000000100113ba4 in reabstraction thunk helper from @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<Swift.String>, C.UIImageOrientation, Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>)) -> (@out ()) to @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:757
#17 0x0000000100108c60 in partial apply forwarder for reabstraction thunk helper from @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<Swift.String>, C.UIImageOrientation, Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>)) -> (@out ()) to @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) ()
#18 0x0000000100113f3c in reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<Swift.String>, @unowned C.UIImageOrientation, @owned Swift.ImplicitlyUnwrappedOptional<Swift.Dictionary<ObjectiveC.NSObject, Swift.AnyObject>>) -> (@unowned ()) to @callee_unowned @objc_block (@unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSString>, @unowned C.UIImageOrientation, @unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSDictionary>) -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:757
#19 0x000000018bad7380 in __65-[PHImageManager requestImageDataForAsset:options:resultHandler:]_block_invoke1437 ()
#20 0x0000000100a44e30 in _dispatch_call_block_and_release ()
#21 0x0000000100a44df0 in _dispatch_client_callout ()
#22 0x0000000100a4975c in _dispatch_main_queue_callback_4CF ()
#23 0x0000000187c5dfa4 in __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ ()
#24 0x0000000187c5c04c in __CFRunLoopRun ()
#25 0x0000000187b890a4 in CFRunLoopRunSpecific ()
#26 0x0000000190d335a4 in GSEventRunModal ()
#27 0x000000018c4be3c0 in UIApplicationMain ()
#28 0x0000000100118e58 in main at /Users/possen/projects/wdp/App/main.m:14
#29 0x0000000198a1ea08 in start ()
Enqueued from com.apple.root.default-qos (Thread 19)Queue : com.apple.root.default-qos (concurrent)
#0 0x0000000100a4dc38 in _dispatch_barrier_async_f ()
#1 0x000000018bac8df0 in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke729 ()
#2 0x0000000100a44e30 in _dispatch_call_block_and_release ()
#3 0x0000000100a44df0 in _dispatch_client_callout ()
#4 0x0000000100a519a0 in _dispatch_root_queue_drain ()
#5 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#6 0x0000000198bd12e4 in _pthread_wqthread ()
#7 0x0000000198bd0fa8 in start_wqthread ()
Enqueued from NSManagedObjectContext 0x15fd29310 (Thread 19)Queue : NSManagedObjectContext 0x15fd29310 (serial)
#0 0x0000000100a4655c in dispatch_async ()
#1 0x000000018baca94c in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke_2808 ()
#2 0x000000018bacad60 in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke_2813 ()
#3 0x000000018bac499c in __226-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesPossiblyThruAssetsdAndCPLWithRequest:library:format:optimalSourcePixelSize:wantsProperties:networkAccessAllowed:networkAccessForced:trackCPLDownload:sync:completionHandler:]_block_invoke ()
#4 0x000000018bac45d0 in -[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesPossiblyThruAssetsdAndCPLWithRequest:library:format:optimalSourcePixelSize:wantsProperties:networkAccessAllowed:networkAccessForced:trackCPLDownload:sync:completionHandler:] ()
#5 0x000000018bacaa8c in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke812 ()
#6 0x000000019291b2b0 in __82-[PLPhotoLibrary _withDispatchGroup:synchronously:performBlock:completionHandler:]_block_invoke ()
#7 0x00000001879f9270 in developerSubmittedBlockToNSManagedObjectContextPerform ()
#8 0x0000000100a44df0 in _dispatch_client_callout ()
#9 0x0000000100a4f854 in _dispatch_queue_drain ()
#10 0x0000000100a48120 in _dispatch_queue_invoke ()
#11 0x0000000100a5175c in _dispatch_root_queue_drain ()
#12 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#13 0x0000000198bd12e4 in _pthread_wqthread ()
#14 0x0000000198bd0fa8 in start_wqthread ()
Enqueued from com.apple.root.default-qos (Thread 25)Queue : com.apple.root.default-qos (concurrent)
#0 0x0000000100a4dc38 in _dispatch_barrier_async_f ()
#1 0x000000019291b278 in -[PLPhotoLibrary _withDispatchGroup:synchronously:performBlock:completionHandler:] ()
#2 0x000000018baca8cc in __163-[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:]_block_invoke807 ()
#3 0x0000000100a4da28 in _dispatch_block_async_invoke_and_release ()
#4 0x0000000100a44df0 in _dispatch_client_callout ()
#5 0x0000000100a519a0 in _dispatch_root_queue_drain ()
#6 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#7 0x0000000198bd12e4 in _pthread_wqthread ()
#8 0x0000000198bd0fa8 in start_wqthread ()
Enqueued from com.apple.root.utility-qos (Thread 24)Queue : com.apple.root.utility-qos (concurrent)
#0 0x0000000100a52b7c in _dispatch_async_f_slow ()
#1 0x000000018bac6e7c in -[PHCoreImageManager _fetchAnySizeImageAsNon5551BytesWithRequest:library:format:bestFormat:optimalSourcePixelSize:sync:fireAndForgetCPLDownload:completionHandler:] ()
#2 0x000000018bacf618 in -[PHCoreImageManager _processImageRequest:sync:] ()
#3 0x000000018bad3214 in -[PHImageManager requestAsynchronousImageForAsset:chainedToMasterRequest:targetSize:contentMode:options:resultHandler:] ()
#4 0x000000018bad3048 in -[PHImageManager requestAsynchronousImageForAsset:targetSize:contentMode:options:resultHandler:] ()
#5 0x000000018bad6ec4 in -[PHImageManager requestImageDataForAsset:options:resultHandler:] ()
#6 0x0000000100111cc4 in Photos.UploadManager.((exportAsset in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadManager) -> (ObjectiveC.PHAsset, name : Swift.String, device : Photos.UploadDevice) -> ()).(closure #1) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:755
#7 0x000000010009d958 in reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_unowned @objc_block () -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/CameraRollController.swift:50
#8 0x0000000100a44e30 in _dispatch_call_block_and_release ()
#9 0x0000000100a44df0 in _dispatch_client_callout ()
#10 0x0000000100a519a0 in _dispatch_root_queue_drain ()
#11 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#12 0x0000000198bd12e4 in _pthread_wqthread ()
#13 0x0000000198bd0fa8 in start_wqthread ()
Enqueued from NSOperationQueue 0x170434820 :: NSOperation 0x1742564d0 (Thread 17)Queue : NSOperationQueue 0x170434820 :: NSOperation 0x1742564d0 (serial)
#0 0x0000000100a52b7c in _dispatch_async_f_slow ()
#1 0x0000000100102ddc in Photos.UploadManager.(exportAsset in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadManager)(ObjectiveC.PHAsset, name : Swift.String, device : Photos.UploadDevice) -> () at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:739
#2 0x000000010010fc2c in Photos.UploadDevice.((processAssets in _2685BBCA4A43EF0FB41323498998E5EB) (Photos.UploadDevice) -> () -> ()).(closure #1).(closure #1) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:507
#3 0x000000010010ca70 in Photos.UploadDevice.(fetchRemoteDirList (Photos.UploadDevice) -> (ObjectiveC.NSURL, block : (Swift.Optional<Swift.Dictionary<Swift.String, Photos.FileEntry>>, Swift.Optional<ObjectiveC.NSError>) -> ()) -> ()).(closure #2) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:284
#4 0x000000010010b198 in reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) to @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>)) -> (@out ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:236
#5 0x00000001000f3aec in partial apply forwarder for reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) to @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>)) -> (@out ()) with unmangled suffix "52" ()
#6 0x000000010010b3ec in reabstraction thunk helper from @callee_owned (@in (Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>)) -> (@out ()) to @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:236
#7 0x000000010010b444 in reabstraction thunk helper from @callee_owned (@owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @owned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) to @callee_unowned @objc_block (@unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSData>, @unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSURLResponse>, @unowned Swift.ImplicitlyUnwrappedOptional<ObjectiveC.NSError>) -> (@unowned ()) at /Users/possen/projects/wdp/App/Classes/UploadManager.swift:236
#8 0x000000018763b2d4 in __49-[__NSCFLocalSessionTask _task_onqueue_didFinish]_block_invoke ()
#9 0x0000000188b5f508 in __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ ()
#10 0x0000000188ab0c94 in -[NSBlockOperation main] ()
#11 0x0000000188aa061c in -[__NSOperationInternal _start:] ()
#12 0x0000000188b6226c in __NSOQSchedule_f ()
#13 0x0000000100a44df0 in _dispatch_client_callout ()
#14 0x0000000100a4f854 in _dispatch_queue_drain ()
#15 0x0000000100a48120 in _dispatch_queue_invoke ()
#16 0x0000000100a5175c in _dispatch_root_queue_drain ()
#17 0x0000000100a52f18 in _dispatch_worker_thread3 ()
#18 0x0000000198bd12e4 in _pthread_wqthread ()
#19 0x0000000198bd0fa8 in start_wqthread ()
我以某种方式误解了 PHImageRequestOptions 对象上的同步标志。将此设置为 true 将在发出图像请求的同一线程上调用它，这正是我想要的。关闭它后，它将响应发送到另一个导致问题出现的线程。