DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (d1ed7de67f5a)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634
/* 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/. */

#include "MediaEngine.h"
#include "mozilla/Services.h"
#include "mozilla/unused.h"
#include "nsIMediaManager.h"

#include "nsHashKeys.h"
#include "nsGlobalWindow.h"
#include "nsClassHashtable.h"
#include "nsRefPtrHashtable.h"
#include "nsIObserver.h"
#include "nsIPrefService.h"
#include "nsIPrefBranch.h"

#include "nsPIDOMWindow.h"
#include "nsIDOMNavigatorUserMedia.h"
#include "nsXULAppAPI.h"
#include "mozilla/Attributes.h"
#include "mozilla/Preferences.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/dom/MediaStreamBinding.h"
#include "mozilla/dom/MediaStreamTrackBinding.h"
#include "prlog.h"
#include "DOMMediaStream.h"

#ifdef MOZ_WEBRTC
#include "mtransport/runnable_utils.h"
#endif

// Note, these suck in Windows headers, unfortunately.
#include "base/thread.h"
#include "base/task.h"

#ifdef MOZ_WIDGET_GONK
#include "DOMCameraManager.h"
#endif

namespace mozilla {
namespace dom {
struct MediaStreamConstraints;
class NavigatorUserMediaSuccessCallback;
class NavigatorUserMediaErrorCallback;
}

#ifdef PR_LOGGING
extern PRLogModuleInfo* GetMediaManagerLog();
#define MM_LOG(msg) PR_LOG(GetMediaManagerLog(), PR_LOG_DEBUG, msg)
#else
#define MM_LOG(msg)
#endif

/**
 * This class is an implementation of MediaStreamListener. This is used
 * to Start() and Stop() the underlying MediaEngineSource when MediaStreams
 * are assigned and deassigned in content.
 */
class GetUserMediaCallbackMediaStreamListener : public MediaStreamListener
{
public:
  // Create in an inactive state
  GetUserMediaCallbackMediaStreamListener(base::Thread *aThread,
    uint64_t aWindowID)
    : mMediaThread(aThread)
    , mWindowID(aWindowID)
    , mStopped(false)
    , mFinished(false)
    , mLock("mozilla::GUMCMSL")
    , mRemoved(false) {}

  ~GetUserMediaCallbackMediaStreamListener()
  {
    // It's OK to release mStream on any thread; they have thread-safe
    // refcounts.
  }

  void Activate(already_AddRefed<SourceMediaStream> aStream,
    MediaEngineSource* aAudioSource,
    MediaEngineSource* aVideoSource)
  {
    NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
    mStream = aStream;
    mAudioSource = aAudioSource;
    mVideoSource = aVideoSource;
    mLastEndTimeAudio = 0;
    mLastEndTimeVideo = 0;

    mStream->AddListener(this);
  }

  MediaStream *Stream() // Can be used to test if Activate was called
  {
    return mStream;
  }
  SourceMediaStream *GetSourceStream()
  {
    NS_ASSERTION(mStream,"Getting stream from never-activated GUMCMSListener");
    if (!mStream) {
      return nullptr;
    }
    return mStream->AsSourceStream();
  }

  void StopScreenWindowSharing();

  void StopTrack(TrackID aID, bool aIsAudio);

  // mVideo/AudioSource are set by Activate(), so we assume they're capturing
  // if set and represent a real capture device.
  bool CapturingVideo()
  {
    NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
    return mVideoSource && !mStopped &&
           mVideoSource->GetMediaSource() == MediaSourceType::Camera &&
           (!mVideoSource->IsFake() ||
            Preferences::GetBool("media.navigator.permission.fake"));
  }
  bool CapturingAudio()
  {
    NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
    return mAudioSource && !mStopped &&
           (!mAudioSource->IsFake() ||
            Preferences::GetBool("media.navigator.permission.fake"));
  }
  bool CapturingScreen()
  {
    NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
    return mVideoSource && !mStopped && !mVideoSource->IsAvailable() &&
           mVideoSource->GetMediaSource() == MediaSourceType::Screen;
  }
  bool CapturingWindow()
  {
    NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
    return mVideoSource && !mStopped && !mVideoSource->IsAvailable() &&
           mVideoSource->GetMediaSource() == MediaSourceType::Window;
  }
  bool CapturingApplication()
  {
    NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
    return mVideoSource && !mStopped && !mVideoSource->IsAvailable() &&
           mVideoSource->GetMediaSource() == MediaSourceType::Application;
  }

  void SetStopped()
  {
    mStopped = true;
  }

  // implement in .cpp to avoid circular dependency with MediaOperationTask
  // Can be invoked from EITHER MainThread or MSG thread
  void Invalidate();

  void
  AudioConfig(bool aEchoOn, uint32_t aEcho,
              bool aAgcOn, uint32_t aAGC,
              bool aNoiseOn, uint32_t aNoise,
              int32_t aPlayoutDelay);

  void
  Remove()
  {
    NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
    // allow calling even if inactive (!mStream) for easier cleanup
    // Caller holds strong reference to us, so no death grip required
    MutexAutoLock lock(mLock); // protect access to mRemoved
    if (mStream && !mRemoved) {
      MM_LOG(("Listener removed on purpose, mFinished = %d", (int) mFinished));
      mRemoved = true; // RemoveListener is async, avoid races
      // If it's destroyed, don't call - listener will be removed and we'll be notified!
      if (!mStream->IsDestroyed()) {
        mStream->RemoveListener(this);
      }
    }
  }

  // Proxy NotifyPull() to sources
  virtual void
  NotifyPull(MediaStreamGraph* aGraph, StreamTime aDesiredTime) MOZ_OVERRIDE
  {
    // Currently audio sources ignore NotifyPull, but they could
    // watch it especially for fake audio.
    if (mAudioSource) {
      mAudioSource->NotifyPull(aGraph, mStream, kAudioTrack, aDesiredTime, mLastEndTimeAudio);
    }
    if (mVideoSource) {
      mVideoSource->NotifyPull(aGraph, mStream, kVideoTrack, aDesiredTime, mLastEndTimeVideo);
    }
  }

  virtual void
  NotifyEvent(MediaStreamGraph* aGraph,
              MediaStreamListener::MediaStreamGraphEvent aEvent) MOZ_OVERRIDE
  {
    switch (aEvent) {
      case EVENT_FINISHED:
        NotifyFinished(aGraph);
        break;
      case EVENT_REMOVED:
        NotifyRemoved(aGraph);
        break;
      case EVENT_HAS_DIRECT_LISTENERS:
        NotifyDirectListeners(aGraph, true);
        break;
      case EVENT_HAS_NO_DIRECT_LISTENERS:
        NotifyDirectListeners(aGraph, false);
        break;
      default:
        break;
    }
  }

  virtual void
  NotifyFinished(MediaStreamGraph* aGraph);

  virtual void
  NotifyRemoved(MediaStreamGraph* aGraph);

  virtual void
  NotifyDirectListeners(MediaStreamGraph* aGraph, bool aHasListeners);

private:
  // Set at construction
  base::Thread* mMediaThread;
  uint64_t mWindowID;

  bool mStopped; // MainThread only

  // Set at Activate on MainThread

  // Accessed from MediaStreamGraph thread, MediaManager thread, and MainThread
  // No locking needed as they're only addrefed except on the MediaManager thread
  nsRefPtr<MediaEngineSource> mAudioSource; // threadsafe refcnt
  nsRefPtr<MediaEngineSource> mVideoSource; // threadsafe refcnt
  nsRefPtr<SourceMediaStream> mStream; // threadsafe refcnt
  TrackTicks mLastEndTimeAudio;
  TrackTicks mLastEndTimeVideo;
  bool mFinished;

  // Accessed from MainThread and MSG thread
  Mutex mLock; // protects mRemoved access from MainThread
  bool mRemoved;
};

class GetUserMediaNotificationEvent: public nsRunnable
{
  public:
    enum GetUserMediaStatus {
      STARTING,
      STOPPING,
      STOPPED_TRACK
    };
    GetUserMediaNotificationEvent(GetUserMediaCallbackMediaStreamListener* aListener,
                                  GetUserMediaStatus aStatus,
                                  bool aIsAudio, bool aIsVideo, uint64_t aWindowID)
    : mListener(aListener) , mStatus(aStatus) , mIsAudio(aIsAudio)
    , mIsVideo(aIsVideo), mWindowID(aWindowID) {}

    GetUserMediaNotificationEvent(GetUserMediaStatus aStatus,
                                  already_AddRefed<DOMMediaStream> aStream,
                                  DOMMediaStream::OnTracksAvailableCallback* aOnTracksAvailableCallback,
                                  bool aIsAudio, bool aIsVideo, uint64_t aWindowID,
                                  already_AddRefed<nsIDOMGetUserMediaErrorCallback> aError)
    : mStream(aStream), mOnTracksAvailableCallback(aOnTracksAvailableCallback),
      mStatus(aStatus), mIsAudio(aIsAudio), mIsVideo(aIsVideo), mWindowID(aWindowID),
      mError(aError) {}
    virtual ~GetUserMediaNotificationEvent()
    {

    }

    NS_IMETHOD Run() MOZ_OVERRIDE;

  protected:
    nsRefPtr<GetUserMediaCallbackMediaStreamListener> mListener; // threadsafe
    nsRefPtr<DOMMediaStream> mStream;
    nsAutoPtr<DOMMediaStream::OnTracksAvailableCallback> mOnTracksAvailableCallback;
    GetUserMediaStatus mStatus;
    bool mIsAudio;
    bool mIsVideo;
    uint64_t mWindowID;
    nsRefPtr<nsIDOMGetUserMediaErrorCallback> mError;
};

typedef enum {
  MEDIA_START,
  MEDIA_STOP,
  MEDIA_STOP_TRACK,
  MEDIA_DIRECT_LISTENERS
} MediaOperation;

class MediaManager;
class GetUserMediaTask;

/**
 * Send an error back to content. The error is the form a string.
 * Do this only on the main thread. The success callback is also passed here
 * so it can be released correctly.
 */
class ErrorCallbackRunnable : public nsRunnable
{
public:
  ErrorCallbackRunnable(
    nsCOMPtr<nsIDOMGetUserMediaSuccessCallback>& aSuccess,
    nsCOMPtr<nsIDOMGetUserMediaErrorCallback>& aError,
    const nsAString& aErrorMsg, uint64_t aWindowID);
  NS_IMETHOD Run();
private:
  ~ErrorCallbackRunnable();

  nsCOMPtr<nsIDOMGetUserMediaSuccessCallback> mSuccess;
  nsCOMPtr<nsIDOMGetUserMediaErrorCallback> mError;
  const nsString mErrorMsg;
  uint64_t mWindowID;
  nsRefPtr<MediaManager> mManager; // get ref to this when creating the runnable
};

class ReleaseMediaOperationResource : public nsRunnable
{
public:
  ReleaseMediaOperationResource(already_AddRefed<DOMMediaStream> aStream,
    DOMMediaStream::OnTracksAvailableCallback* aOnTracksAvailableCallback):
    mStream(aStream),
    mOnTracksAvailableCallback(aOnTracksAvailableCallback) {}
  NS_IMETHOD Run() MOZ_OVERRIDE {return NS_OK;}
private:
  nsRefPtr<DOMMediaStream> mStream;
  nsAutoPtr<DOMMediaStream::OnTracksAvailableCallback> mOnTracksAvailableCallback;
};

// Generic class for running long media operations like Start off the main
// thread, and then (because nsDOMMediaStreams aren't threadsafe),
// ProxyReleases mStream since it's cycle collected.
class MediaOperationTask : public Task
{
public:
  // so we can send Stop without AddRef()ing from the MSG thread
  MediaOperationTask(MediaOperation aType,
    GetUserMediaCallbackMediaStreamListener* aListener,
    DOMMediaStream* aStream,
    DOMMediaStream::OnTracksAvailableCallback* aOnTracksAvailableCallback,
    MediaEngineSource* aAudioSource,
    MediaEngineSource* aVideoSource,
    bool aBool,
    uint64_t aWindowID,
    already_AddRefed<nsIDOMGetUserMediaErrorCallback> aError)
    : mType(aType)
    , mStream(aStream)
    , mOnTracksAvailableCallback(aOnTracksAvailableCallback)
    , mAudioSource(aAudioSource)
    , mVideoSource(aVideoSource)
    , mListener(aListener)
    , mBool(aBool)
    , mWindowID(aWindowID)
    , mError(aError)
  {}

  ~MediaOperationTask()
  {
    // MediaStreams can be released on any thread.
  }

  void
  ReturnCallbackError(nsresult rv, const char* errorLog)
  {
    MM_LOG(("%s , rv=%d", errorLog, rv));
    NS_DispatchToMainThread(new ReleaseMediaOperationResource(mStream.forget(),
          mOnTracksAvailableCallback.forget()));
    nsString log;

    log.AssignASCII(errorLog, strlen(errorLog));
    nsCOMPtr<nsIDOMGetUserMediaSuccessCallback> success;
    NS_DispatchToMainThread(new ErrorCallbackRunnable(success, mError,
      log, mWindowID));
  }

  void
  Run()
  {
    SourceMediaStream *source = mListener->GetSourceStream();
    // No locking between these is required as all the callbacks for the
    // same MediaStream will occur on the same thread.
    if (!source) // means the stream was never Activated()
      return;

    switch (mType) {
      case MEDIA_START:
        {
          NS_ASSERTION(!NS_IsMainThread(), "Never call on main thread");
          nsresult rv;

          source->SetPullEnabled(true);

          DOMMediaStream::TrackTypeHints expectedTracks = 0;
          if (mAudioSource) {
            rv = mAudioSource->Start(source, kAudioTrack);
            if (NS_SUCCEEDED(rv)) {
              expectedTracks |= DOMMediaStream::HINT_CONTENTS_AUDIO;
            } else {
              ReturnCallbackError(rv, "Starting audio failed");
              return;
            }
          }
          if (mVideoSource) {
            rv = mVideoSource->Start(source, kVideoTrack);
            if (NS_SUCCEEDED(rv)) {
              expectedTracks |= DOMMediaStream::HINT_CONTENTS_VIDEO;
            } else {
              ReturnCallbackError(rv, "Starting video failed");
              return;
            }
          }

          mOnTracksAvailableCallback->SetExpectedTracks(expectedTracks);

          MM_LOG(("started all sources"));
          // Forward mOnTracksAvailableCallback to GetUserMediaNotificationEvent,
          // because mOnTracksAvailableCallback needs to be added to mStream
          // on the main thread.
          nsIRunnable *event =
            new GetUserMediaNotificationEvent(GetUserMediaNotificationEvent::STARTING,
                                              mStream.forget(),
                                              mOnTracksAvailableCallback.forget(),
                                              mAudioSource != nullptr,
                                              mVideoSource != nullptr,
                                              mWindowID, mError.forget());
          // event must always be released on mainthread due to the JS callbacks
          // in the TracksAvailableCallback
          NS_DispatchToMainThread(event);
        }
        break;

      case MEDIA_STOP:
      case MEDIA_STOP_TRACK:
        {
          NS_ASSERTION(!NS_IsMainThread(), "Never call on main thread");
          if (mAudioSource) {
            mAudioSource->Stop(source, kAudioTrack);
            mAudioSource->Deallocate();
          }
          if (mVideoSource) {
            mVideoSource->Stop(source, kVideoTrack);
            mVideoSource->Deallocate();
          }
          // Do this after stopping all tracks with EndTrack()
          if (mBool) {
            source->Finish();
          }

          nsIRunnable *event =
            new GetUserMediaNotificationEvent(mListener,
                                              mType == MEDIA_STOP ?
                                              GetUserMediaNotificationEvent::STOPPING :
                                              GetUserMediaNotificationEvent::STOPPED_TRACK,
                                              mAudioSource != nullptr,
                                              mVideoSource != nullptr,
                                              mWindowID);
          // event must always be released on mainthread due to the JS callbacks
          // in the TracksAvailableCallback
          NS_DispatchToMainThread(event);
        }
        break;

      case MEDIA_DIRECT_LISTENERS:
        {
          NS_ASSERTION(!NS_IsMainThread(), "Never call on main thread");
          if (mVideoSource) {
            mVideoSource->SetDirectListeners(mBool);
          }
        }
        break;

      default:
        MOZ_ASSERT(false,"invalid MediaManager operation");
        break;
    }
  }

private:
  MediaOperation mType;
  nsRefPtr<DOMMediaStream> mStream;
  nsAutoPtr<DOMMediaStream::OnTracksAvailableCallback> mOnTracksAvailableCallback;
  nsRefPtr<MediaEngineSource> mAudioSource; // threadsafe
  nsRefPtr<MediaEngineSource> mVideoSource; // threadsafe
  nsRefPtr<GetUserMediaCallbackMediaStreamListener> mListener; // threadsafe
  bool mBool;
  uint64_t mWindowID;
  nsCOMPtr<nsIDOMGetUserMediaErrorCallback> mError;
};

typedef nsTArray<nsRefPtr<GetUserMediaCallbackMediaStreamListener> > StreamListeners;
typedef nsClassHashtable<nsUint64HashKey, StreamListeners> WindowTable;

class MediaDevice : public nsIMediaDevice
{
public:
  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIMEDIADEVICE

  static MediaDevice* Create(MediaEngineVideoSource* source);
  static MediaDevice* Create(MediaEngineAudioSource* source);

protected:
  virtual ~MediaDevice() {}
  explicit MediaDevice(MediaEngineSource* aSource);
  nsString mName;
  nsString mID;
  bool mHasFacingMode;
  dom::VideoFacingModeEnum mFacingMode;
  MediaSourceType mMediaSource;
  nsRefPtr<MediaEngineSource> mSource;
};

class VideoDevice : public MediaDevice
{
public:
  explicit VideoDevice(MediaEngineVideoSource* aSource);
  NS_IMETHOD GetType(nsAString& aType);
  MediaEngineVideoSource* GetSource();
};

class AudioDevice : public MediaDevice
{
public:
  explicit AudioDevice(MediaEngineAudioSource* aSource);
  NS_IMETHOD GetType(nsAString& aType);
  MediaEngineAudioSource* GetSource();
};

// we could add MediaManager if needed
typedef void (*WindowListenerCallback)(MediaManager *aThis,
                                       uint64_t aWindowID,
                                       StreamListeners *aListeners,
                                       void *aData);

class MediaManager MOZ_FINAL : public nsIMediaManagerService,
                               public nsIObserver
{
public:
  static already_AddRefed<MediaManager> GetInstance();

  // NOTE: never Dispatch(....,NS_DISPATCH_SYNC) to the MediaManager
  // thread from the MainThread, as we NS_DISPATCH_SYNC to MainThread
  // from MediaManager thread.
  static MediaManager* Get();
  static MessageLoop* GetMessageLoop();

  static bool Exists()
  {
    return !!sSingleton;
  }

  static nsresult NotifyRecordingStatusChange(nsPIDOMWindow* aWindow,
                                              const nsString& aMsg,
                                              const bool& aIsAudio,
                                              const bool& aIsVideo);

  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIOBSERVER
  NS_DECL_NSIMEDIAMANAGERSERVICE

  MediaEngine* GetBackend(uint64_t aWindowId = 0);
  StreamListeners *GetWindowListeners(uint64_t aWindowId) {
    NS_ASSERTION(NS_IsMainThread(), "Only access windowlist on main thread");

    return mActiveWindows.Get(aWindowId);
  }
  void RemoveWindowID(uint64_t aWindowId);
  bool IsWindowStillActive(uint64_t aWindowId) {
    return !!GetWindowListeners(aWindowId);
  }
  // Note: also calls aListener->Remove(), even if inactive
  void RemoveFromWindowList(uint64_t aWindowID,
    GetUserMediaCallbackMediaStreamListener *aListener);

  nsresult GetUserMedia(bool aPrivileged,
    nsPIDOMWindow* aWindow,
    const dom::MediaStreamConstraints& aRawConstraints,
    nsIDOMGetUserMediaSuccessCallback* onSuccess,
    nsIDOMGetUserMediaErrorCallback* onError);

  nsresult GetUserMediaDevices(nsPIDOMWindow* aWindow,
    const dom::MediaStreamConstraints& aConstraints,
    nsIGetUserMediaDevicesSuccessCallback* onSuccess,
    nsIDOMGetUserMediaErrorCallback* onError,
    uint64_t aInnerWindowID = 0);
  void OnNavigation(uint64_t aWindowID);

  MediaEnginePrefs mPrefs;

private:
  WindowTable *GetActiveWindows() {
    NS_ASSERTION(NS_IsMainThread(), "Only access windowlist on main thread");
    return &mActiveWindows;
  }

  void GetPref(nsIPrefBranch *aBranch, const char *aPref,
               const char *aData, int32_t *aVal);
  void GetPrefBool(nsIPrefBranch *aBranch, const char *aPref,
                   const char *aData, bool *aVal);
  void GetPrefs(nsIPrefBranch *aBranch, const char *aData);

  // Make private because we want only one instance of this class
  MediaManager();

  ~MediaManager() {}

  void StopScreensharing(uint64_t aWindowID);
  void IterateWindowListeners(nsPIDOMWindow *aWindow,
                              WindowListenerCallback aCallback,
                              void *aData);

  void StopMediaStreams();

  // ONLY access from MainThread so we don't need to lock
  WindowTable mActiveWindows;
  nsClassHashtable<nsStringHashKey, GetUserMediaTask> mActiveCallbacks;
  nsClassHashtable<nsUint64HashKey, nsTArray<nsString>> mCallIds;
  // Always exists
  nsAutoPtr<base::Thread> mMediaThread;

  Mutex mMutex;
  // protected with mMutex:
  RefPtr<MediaEngine> mBackend;

  static StaticRefPtr<MediaManager> sSingleton;

#ifdef MOZ_B2G_CAMERA
  nsRefPtr<nsDOMCameraManager> mCameraManager;
#endif
};

} // namespace mozilla