зеркало из https://github.com/mozilla/gecko-dev.git
126 строки
4.4 KiB
C++
126 строки
4.4 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_dom_PromiseWorkerProxy_h
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#define mozilla_dom_PromiseWorkerProxy_h
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// Required for Promise::PromiseTaskSync.
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#include "mozilla/dom/Promise.h"
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#include "mozilla/dom/PromiseNativeHandler.h"
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#include "mozilla/dom/workers/bindings/WorkerFeature.h"
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#include "nsProxyRelease.h"
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namespace mozilla {
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namespace dom {
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class Promise;
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namespace workers {
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class WorkerPrivate;
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}
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// A proxy to catch the resolved/rejected Promise's result from the main thread
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// and resolve/reject that on the worker thread eventually.
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//
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// How to use:
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//
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// 1. Create a Promise on the worker thread and return it to the content
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// script:
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//
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// nsRefPtr<Promise> promise = Promise::Create(workerPrivate->GlobalScope(), aRv);
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// if (aRv.Failed()) {
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// return nullptr;
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// }
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// // Pass |promise| around to the WorkerMainThreadRunnable
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// return promise.forget();
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//
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// 2. In your WorkerMainThreadRunnable's ctor, create a PromiseWorkerProxy
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// which holds a nsRefPtr<Promise> to the Promise created at #1.
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//
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// 3. In your WorkerMainThreadRunnable::MainThreadRun(), obtain a Promise on
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// the main thread and call its AppendNativeHandler(PromiseNativeHandler*)
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// to bind the PromiseWorkerProxy created at #2.
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//
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// 4. Then the Promise results returned by ResolvedCallback/RejectedCallback
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// will be dispatched as a WorkerRunnable to the worker thread to
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// resolve/reject the Promise created at #1.
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//
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// PromiseWorkerProxy can also be used in situations where there is no main
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// thread Promise, or where special handling is required on the worker thread
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// for promise resolution. Create a PromiseWorkerProxy as in steps 1 and
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// 2 above. When the main thread is ready to resolve the worker thread promise,
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// dispatch a runnable to the worker. Use GetWorkerPrivate() to acquire the
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// worker. This might be null! In the WorkerRunnable's WorkerRun() use
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// GetWorkerPromise() to access the Promise and resolve/reject it. Then call
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// CleanUp() on the worker
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// thread.
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class PromiseWorkerProxy : public PromiseNativeHandler,
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public workers::WorkerFeature
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{
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friend class PromiseWorkerProxyRunnable;
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// This overrides the non-threadsafe refcounting in PromiseNativeHandler.
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NS_INLINE_DECL_THREADSAFE_REFCOUNTING(PromiseWorkerProxy, MOZ_OVERRIDE)
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public:
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static already_AddRefed<PromiseWorkerProxy>
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Create(workers::WorkerPrivate* aWorkerPrivate,
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Promise* aWorkerPromise,
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const JSStructuredCloneCallbacks* aCallbacks = nullptr);
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workers::WorkerPrivate* GetWorkerPrivate() const;
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Promise* GetWorkerPromise() const;
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void StoreISupports(nsISupports* aSupports);
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void CleanUp(JSContext* aCx);
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protected:
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virtual void ResolvedCallback(JSContext* aCx,
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JS::Handle<JS::Value> aValue) MOZ_OVERRIDE;
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virtual void RejectedCallback(JSContext* aCx,
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JS::Handle<JS::Value> aValue) MOZ_OVERRIDE;
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virtual bool Notify(JSContext* aCx, workers::Status aStatus) MOZ_OVERRIDE;
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private:
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PromiseWorkerProxy(workers::WorkerPrivate* aWorkerPrivate,
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Promise* aWorkerPromise,
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const JSStructuredCloneCallbacks* aCallbacks = nullptr);
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virtual ~PromiseWorkerProxy();
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// Function pointer for calling Promise::{ResolveInternal,RejectInternal}.
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typedef void (Promise::*RunCallbackFunc)(JSContext*,
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JS::Handle<JS::Value>);
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void RunCallback(JSContext* aCx,
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JS::Handle<JS::Value> aValue,
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RunCallbackFunc aFunc);
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workers::WorkerPrivate* mWorkerPrivate;
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// This lives on the worker thread.
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nsRefPtr<Promise> mWorkerPromise;
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bool mCleanedUp; // To specify if the cleanUp() has been done.
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const JSStructuredCloneCallbacks* mCallbacks;
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// Aimed to keep objects alive when doing the structured-clone read/write,
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// which can be added by calling StoreISupports() on the main thread.
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nsTArray<nsMainThreadPtrHandle<nsISupports>> mSupportsArray;
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// Ensure the worker and the main thread won't race to access |mCleanedUp|.
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Mutex mCleanUpLock;
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};
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} // namespace dom
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} // namespace mozilla
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#endif // mozilla_dom_PromiseWorkerProxy_h
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