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Ramanpreet Nara
2c473e1a38
Summary: ## Problems: In my investigation of T65656635, I realized that the TurboModule system has a number of problems: - In TurboModules, we use 1 lock to create n TurboModules. We should change this setup to n locks for n TurboModules. This way, two threads creating two different NativeModules don't compete for the same lock. Also, this is how it's done in Android (TurboModules & NativeModules), and iOS (NativeModules). - In TurboModules, we don't calculate "requires main queue setup" faithfully. In the legacy system, if a NativeModule has a custom `init` method or a custom `constantsToExport` method, it "requires main queue setup" with a warning. - In TurboModules, we don't create the NativeModule on the main queue, if "requires main queue setup" is true. Instead, the NativeModule is always created on the thread that requires it. - In TurboModules, we don't perform any concurrency control around `id<RCTTurboModule>` setup. We should. ## What this diff does In this diff, I fixed all the aforementioned issues by re-implementing `provideRCTTurboModule:`. **Algorithm Notes:** - **Gist:** When `n` threads race to create NativeModule `x`, only the first thread creates and sets up `x`. All others are told to wait. Once the creator thread finishes its job, it notifies all other waiting threads, which then wake up and return the newly created NativeModule. This algorithm was initially implemented in NativeModules for Android inside (ModuleHolder.java). I modified and implemented it for TurboModules for Android, and now this diff implements it for TurboModules for iOS. - The TurboModule cache is replace with a TurboModuleHolder map. A TurboModuleHolder manages the creation lifecycle of a TurboModule, and holds a condition variable and mutex for doing concurrency control around it. When the bridge invalidates, in TurboModuleManager, we set the `invalidating` flag to true, which prevents the insertion of new entries into the TurboModuleHolder map. - I added a `std::mutex` to serialize calls into the TurboModuleManagerDelegate, so we don't get races if the delegate isn't thread-safe. Changelog: [iOS][Fixed] - Re-implement RCTTurboModuleManager provideRCTTurboModule: Reviewed By: shergin Differential Revision: D21170099 fbshipit-source-id: 8792812c2237d3bfc80c9834c818e011de85b0ea