/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ /** * DecodePool manages the threads used for decoding raster images. */ #ifndef mozilla_image_DecodePool_h #define mozilla_image_DecodePool_h #include "mozilla/Mutex.h" #include "mozilla/StaticPtr.h" #include "nsCOMArray.h" #include "nsCOMPtr.h" #include "nsIEventTarget.h" #include "nsIObserver.h" #include "mozilla/RefPtr.h" class nsIThread; class nsIThreadPool; namespace mozilla { namespace image { class Decoder; class DecodePoolImpl; class IDecodingTask; /** * DecodePool is a singleton class that manages decoding of raster images. It * owns a pool of image decoding threads that are used for asynchronous * decoding. * * DecodePool allows callers to run a decoder, handling management of the * decoder's lifecycle and whether it executes on the main thread, * off-main-thread in the image decoding thread pool, or on some combination of * the two. */ class DecodePool : public nsIObserver { public: NS_DECL_THREADSAFE_ISUPPORTS NS_DECL_NSIOBSERVER /// Initializes the singleton instance. Should be called from the main thread. static void Initialize(); /// Returns the singleton instance. static DecodePool* Singleton(); /// @return the number of processor cores we have available. This is not the /// same as the number of decoding threads we're actually using. static uint32_t NumberOfCores(); /// Ask the DecodePool to run @aTask asynchronously and return immediately. void AsyncRun(IDecodingTask* aTask); /** * Run @aTask synchronously if the task would prefer it. It's up to the task * itself to make this decision; @see IDecodingTask::ShouldPreferSyncRun(). If * @aTask doesn't prefer it, just run @aTask asynchronously and return * immediately. */ void SyncRunIfPreferred(IDecodingTask* aTask); /** * Run @aTask synchronously. This does not guarantee that @aTask will complete * synchronously. If, for example, @aTask doesn't yet have the data it needs to * run synchronously, it may recover by scheduling an async task to finish up * the work when the remaining data is available. */ void SyncRunIfPossible(IDecodingTask* aTask); /** * Returns an event target interface to the DecodePool's I/O thread. Callers * who want to deliver data to workers on the DecodePool can use this event * target. * * @return An nsIEventTarget interface to the thread pool's I/O thread. */ already_AddRefed<nsIEventTarget> GetIOEventTarget(); private: friend class DecodePoolWorker; DecodePool(); virtual ~DecodePool(); static StaticRefPtr<DecodePool> sSingleton; static uint32_t sNumCores; RefPtr<DecodePoolImpl> mImpl; // mMutex protects mThreads and mIOThread. Mutex mMutex; nsTArray<nsCOMPtr<nsIThread>> mThreads; nsCOMPtr<nsIThread> mIOThread; }; } // namespace image } // namespace mozilla #endif // mozilla_image_DecodePool_h