MediaRecorder.h - mozsearch

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim:set ts=2 sw=2 sts=2 et cindent: */

/* 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/. */

#ifndef MediaRecorder_h

#define MediaRecorder_h

#include "mozilla/dom/MediaRecorderBinding.h"

#include "mozilla/DOMEventTargetHelper.h"

#include "mozilla/MozPromise.h"

#include "nsIDocumentActivity.h"

// Max size for allowing queue encoded data in memory

#define MAX_ALLOW_MEMORY_BUFFER 1024000

namespace mozilla {

class AudioNodeTrack;

class DOMMediaStream;

class ErrorResult;

struct MediaRecorderOptions;

class GlobalObject;

namespace dom {

class AudioNode;

class BlobImpl;

class Document;

class DOMException;

/**

 * Implementation of

 * https://w3c.github.io/mediacapture-record/MediaRecorder.html

 * The MediaRecorder accepts a MediaStream as input passed from an application.

 * When the MediaRecorder starts, a MediaEncoder will be created and accepts the

 * MediaStreamTracks in the MediaStream as input source. For each track it

 * creates a TrackEncoder.

 * The MediaEncoder automatically encodes and muxes data from the tracks by the

 * given MIME type, then it stores this data into a MutableBlobStorage object.

 * When a timeslice is set and the MediaEncoder has stored enough data to fill

 * the timeslice, it extracts a Blob from the storage and passes it to

 * MediaRecorder. On RequestData() or Stop(), the MediaEncoder extracts the blob

 * from the storage and returns it to MediaRecorder through a MozPromise.

 * Thread model: When the recorder starts, it creates a worker thread (called

 * the encoder thread) that does all the heavy lifting - encoding, time keeping,

 * muxing.

*/

class MediaRecorder final : public DOMEventTargetHelper,

                            public nsIDocumentActivity {

 public:

  class Session;

  explicit MediaRecorder(nsPIDOMWindowInner* aOwnerWindow);

  static nsTArray<RefPtr<Session>> GetSessions();

  // nsWrapperCache

  JSObject* WrapObject(JSContext* aCx,

                       JS::Handle<JSObject*> aGivenProto) override;

  NS_DECL_ISUPPORTS_INHERITED

  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(MediaRecorder, DOMEventTargetHelper)

  // WebIDL

  // Start recording.

  void Start(const Optional<uint32_t>& timeSlice, ErrorResult& aResult);

  // Stop recording.

  void Stop(ErrorResult& aResult);

  // Pause a recording.

  void Pause(ErrorResult& aResult);

  // Resume a paused recording.

  void Resume(ErrorResult& aResult);

  // Extracts buffered data and fires the dataavailable event.

  void RequestData(ErrorResult& aResult);

  // Return the The DOMMediaStream passed from UA.

  DOMMediaStream* Stream() const { return mStream; }

  // Return the current encoding MIME type selected by the MediaEncoder.

  void GetMimeType(nsString& aMimeType);

  // The current state of the MediaRecorder object.

  RecordingState State() const { return mState; }

  static bool IsTypeSupported(GlobalObject& aGlobal,

                              const nsAString& aMIMEType);

  static bool IsTypeSupported(const nsAString& aMIMEType);

  // Construct a recorder with a DOM media stream object as its source.

  static already_AddRefed<MediaRecorder> Constructor(

      const GlobalObject& aGlobal, DOMMediaStream& aStream,

      const MediaRecorderOptions& aOptions, ErrorResult& aRv);

  // Construct a recorder with a Web Audio destination node as its source.

  static already_AddRefed<MediaRecorder> Constructor(

      const GlobalObject& aGlobal, AudioNode& aAudioNode,

      uint32_t aAudioNodeOutput, const MediaRecorderOptions& aOptions,

      ErrorResult& aRv);

/*

   * Measure the size of the buffer, and heap memory in bytes occupied by

   * mAudioEncoder and mVideoEncoder.

*/

  typedef MozPromise<size_t, size_t, true> SizeOfPromise;

  RefPtr<SizeOfPromise> SizeOfExcludingThis(

      mozilla::MallocSizeOf aMallocSizeOf);

  // EventHandler

  IMPL_EVENT_HANDLER(start)

  IMPL_EVENT_HANDLER(stop)

  IMPL_EVENT_HANDLER(dataavailable)

  IMPL_EVENT_HANDLER(pause)

  IMPL_EVENT_HANDLER(resume)

  IMPL_EVENT_HANDLER(error)

  NS_DECL_NSIDOCUMENTACTIVITY

  uint32_t AudioBitsPerSecond() const { return mAudioBitsPerSecond; }

  uint32_t VideoBitsPerSecond() const { return mVideoBitsPerSecond; }

 protected:

  virtual ~MediaRecorder();

  MediaRecorder& operator=(const MediaRecorder& x) = delete;

  // Create dataavailable event with Blob data and it runs in main thread

  nsresult CreateAndDispatchBlobEvent(BlobImpl* aBlobImpl);

  // Creating a simple event to notify UA simple event.

  void DispatchSimpleEvent(const nsAString& aStr);

  // Creating a error event with message.

  void NotifyError(nsresult aRv);

  MediaRecorder(const MediaRecorder& x) = delete;  // prevent bad usage

  // Remove session pointer.

  void RemoveSession(Session* aSession);

  // Create DOMExceptions capturing the JS stack for async errors. These are

  // created ahead of time rather than on demand when firing an error as the JS

  // stack of the operation that started the async behavior will not be

  // available at the time the error event is fired. Note, depending on when

  // this is called there may not be a JS stack to capture.

  void InitializeDomExceptions();

  // Runs the "Inactivate the recorder" algorithm.

  void Inactivate();

  // Stop the recorder and its internal session. This should be used by

  // sessions that are in the process of being destroyed.

  void StopForSessionDestruction();

  // DOM wrapper for source media stream. Will be null when input is audio node.

  RefPtr<DOMMediaStream> mStream;

  // Source audio node. Will be null when input is a media stream.

  RefPtr<AudioNode> mAudioNode;

  // Source audio node's output index. Will be zero when input is a media

  // stream.

  uint32_t mAudioNodeOutput = 0;

  // The current state of the MediaRecorder object.

  RecordingState mState = RecordingState::Inactive;

  // Hold the sessions reference and clean it when the DestroyRunnable for a

  // session is running.

  nsTArray<RefPtr<Session>> mSessions;

  RefPtr<Document> mDocument;

  nsString mMimeType;

  nsString mConstrainedMimeType;

  uint32_t mAudioBitsPerSecond = 0;

  uint32_t mVideoBitsPerSecond = 0;

  Maybe<uint32_t> mConstrainedBitsPerSecond;

  // DOMExceptions that are created early and possibly thrown in NotifyError.

  // Creating them early allows us to capture the JS stack for which cannot be

  // done at the time the error event is fired.

  RefPtr<DOMException> mOtherDomException;

  RefPtr<DOMException> mSecurityDomException;

  RefPtr<DOMException> mUnknownDomException;

 private:

  // Register MediaRecorder into Document to listen the activity changes.

  void RegisterActivityObserver();

  void UnRegisterActivityObserver();

  bool CheckPermission(const nsString& aType);

};

}  // namespace dom

}  // namespace mozilla

#endif