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The Tor Browser
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DecoderAgent.h (4155B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef DOM_MEDIA_WEBCODECS_DECODERAGENT_H
      8 #define DOM_MEDIA_WEBCODECS_DECODERAGENT_H
      9 
     10 #include "MediaResult.h"
     11 #include "PlatformDecoderModule.h"
     12 #include "mozilla/DefineEnum.h"
     13 #include "mozilla/RefPtr.h"
     14 #include "mozilla/TaskQueue.h"
     15 #include "mozilla/UniquePtr.h"
     16 
     17 class nsISerialEventTarget;
     18 
     19 namespace mozilla {
     20 
     21 class PDMFactory;
     22 class TrackInfo;
     23 
     24 namespace layers {
     25 class ImageContainer;
     26 }  // namespace layers
     27 
     28 // DecoderAgent is a wrapper that contains a MediaDataDecoder. It adapts the
     29 // MediaDataDecoder APIs for use in WebCodecs.
     30 //
     31 // If Configure() is called, Shutdown() must be called to release the resources
     32 // gracefully. Except Shutdown(), all the methods can't be called concurrently,
     33 // meaning a method can only be called when the previous API call has completed.
     34 // The responsability of arranging the method calls is on the caller.
     35 //
     36 // When Shutdown() is called, all the operations in flight are canceled and the
     37 // MediaDataDecoder is shut down. On the other hand, errors are final. A new
     38 // DecoderAgent must be created when an error is encountered.
     39 //
     40 // All the methods need to be called on the DecoderAgent's owner thread. In
     41 // WebCodecs, it's either on the main thread or worker thread.
     42 class DecoderAgent final {
     43 public:
     44  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(DecoderAgent);
     45 
     46  using Id = uint32_t;
     47  DecoderAgent(Id aId, UniquePtr<TrackInfo>&& aInfo);
     48 
     49  // The following APIs are owner thread only.
     50 
     51  using ConfigurePromise = MozPromise<bool, MediaResult, true /* exclusive */>;
     52  RefPtr<ConfigurePromise> Configure(bool aPreferSoftwareDecoder,
     53                                     bool aLowLatency);
     54  RefPtr<ShutdownPromise> Shutdown();
     55  using DecodePromise = MediaDataDecoder::DecodePromise;
     56  RefPtr<DecodePromise> Decode(MediaRawData* aSample);
     57  // WebCodecs's flush() flushes out all the pending decoded data in the
     58  // MediaDataDecoder so it is a combination of Drain and Flush. To distinguish
     59  // the term from MediaDataDecoder's one, we call it DrainAndFlush() here.
     60  RefPtr<DecodePromise> DrainAndFlush();
     61 
     62  const Id mId;  // A unique id.
     63  const UniquePtr<TrackInfo> mInfo;
     64 
     65 private:
     66  ~DecoderAgent();
     67 
     68  // Push out all the data in the MediaDataDecoder's pipeline.
     69  // TODO: MediaDataDecoder should implement this, instead of asking call site
     70  // to run `Drain` multiple times.
     71  RefPtr<DecodePromise> Dry();
     72  void DrainUntilDry();
     73 
     74  MOZ_DEFINE_ENUM_CLASS_WITH_TOSTRING_AT_CLASS_SCOPE(
     75      State, (Unconfigured, Configuring, Configured, Decoding, Flushing,
     76              ShuttingDown, Error));
     77  void SetState(State aState);
     78 
     79  const RefPtr<nsISerialEventTarget> mOwnerThread;
     80  const RefPtr<PDMFactory> mPDMFactory;
     81  const RefPtr<layers::ImageContainer> mImageContainer;
     82  RefPtr<MediaDataDecoder> mDecoder;
     83  State mState;
     84 
     85  // Configure
     86  MozPromiseHolder<ConfigurePromise> mConfigurePromise;
     87  using CreateDecoderPromise = PlatformDecoderModule::CreateDecoderPromise;
     88  MozPromiseRequestHolder<CreateDecoderPromise> mCreateRequest;
     89  using InitPromise = MediaDataDecoder::InitPromise;
     90  MozPromiseRequestHolder<InitPromise> mInitRequest;
     91 
     92  // Shutdown
     93  MozPromiseHolder<ShutdownPromise> mShutdownWhileCreationPromise;
     94 
     95  // Decode
     96  MozPromiseHolder<DecodePromise> mDecodePromise;
     97  MozPromiseRequestHolder<DecodePromise> mDecodeRequest;
     98 
     99  // DrainAndFlush
    100  MozPromiseHolder<DecodePromise> mDrainAndFlushPromise;
    101  MediaDataDecoder::DecodedData mDrainAndFlushData;
    102  MozPromiseRequestHolder<DecodePromise> mDryRequest;
    103  MozPromiseHolder<DecodePromise> mDryPromise;
    104  MediaDataDecoder::DecodedData mDryData;
    105  MozPromiseRequestHolder<DecodePromise> mDrainRequest;
    106  using FlushPromise = MediaDataDecoder::FlushPromise;
    107  MozPromiseRequestHolder<FlushPromise> mFlushRequest;
    108 };
    109 
    110 }  // namespace mozilla
    111 
    112 #endif  // DOM_MEDIA_WEBCODECS_DECODERAGENT_H