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#ifndef MEDIA_CAPTURE_DEVICES_DISPATCHER_H
#define MEDIA_CAPTURE_DEVICES_DISPATCHER_H

#include <deque>
#include <list>
#include <map>
#include <QtCore/qcompilerdetection.h>

#include "web_contents_adapter_client.h"

#include "base/callback.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/singleton.h"
#include "base/observer_list.h"
#include "content/public/browser/media_observer.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"
#include "content/public/browser/web_contents_delegate.h"
#include "content/public/common/media_stream_request.h"

class AudioStreamIndicator;
class DesktopStreamsRegistry;
class MediaStreamCaptureIndicator;

// This singleton is used to receive updates about media events from the content
// layer. Based on Chrome's implementation.
class MediaCaptureDevicesDispatcher : public content::MediaObserver,
                                      public content::NotificationObserver {
 public:

  static MediaCaptureDevicesDispatcher *GetInstance();

  void processMediaAccessRequest(WebContentsAdapterClient *, content::WebContents *, const content::MediaStreamRequest &, const content::MediaResponseCallback &);

  // Called back from our WebContentsAdapter to grant the requested permission.
  void handleMediaAccessPermissionResponse(content::WebContents *, const QUrl &securityOrigin, WebContentsAdapterClient::MediaRequestFlags);

  void getDefaultDevices(const std::string &audioDeviceId, const std::string &videoDeviceId, bool audio, bool video, content::MediaStreamDevices *);

  // Overridden from content::MediaObserver:
  virtual void OnAudioCaptureDevicesChanged(const content::MediaStreamDevices &) Q_DECL_OVERRIDE;
  virtual void OnVideoCaptureDevicesChanged(const content::MediaStreamDevices &) Q_DECL_OVERRIDE;
  virtual void OnMediaRequestStateChanged(int renderProcessId, int renderViewId, int pageRequestId, const content::MediaStreamDevice &device
                                          , content::MediaRequestState state) Q_DECL_OVERRIDE;
  virtual void OnAudioStreamPlayingChanged(int /*render_process_id*/, int /*render_view_id*/, int /*stream_id*/
                                           , bool /*is_playing*/, float /*power_dBFS*/, bool /*clipped*/) Q_DECL_OVERRIDE {}
  virtual void OnCreatingAudioStream(int renderProcessId, int renderViewId) Q_DECL_OVERRIDE;

  DesktopStreamsRegistry *getDesktopStreamsRegistry();

 private:
  friend struct DefaultSingletonTraits<MediaCaptureDevicesDispatcher>;

  struct PendingAccessRequest {
    PendingAccessRequest(const content::MediaStreamRequest &request,
                         const content::MediaResponseCallback &callback);
    ~PendingAccessRequest();

    content::MediaStreamRequest request;
    content::MediaResponseCallback callback;
  };
  typedef std::deque<PendingAccessRequest> RequestsQueue;
  typedef std::map<content::WebContents *, RequestsQueue> RequestsQueues;

  MediaCaptureDevicesDispatcher();
  virtual ~MediaCaptureDevicesDispatcher();

  const content::MediaStreamDevices &getAudioCaptureDevices();
  const content::MediaStreamDevices &getVideoCaptureDevices();

  // content::NotificationObserver implementation.
  virtual void Observe(int type, const content::NotificationSource &source, const content::NotificationDetails &details) Q_DECL_OVERRIDE;

  // Helpers for ProcessMediaAccessRequest().
  void processDesktopCaptureAccessRequest(content::WebContents *, const content::MediaStreamRequest &, const content::MediaResponseCallback &);
  void processScreenCaptureAccessRequest(content::WebContents *,const content::MediaStreamRequest &, const content::MediaResponseCallback &);
  void handleScreenCaptureAccessRequest(content::WebContents *, bool userAccepted, const base::string16 &/*unused callback_input*/);
  void enqueueMediaAccessRequest(content::WebContents *, const content::MediaStreamRequest &, const content::MediaResponseCallback &);
  void ProcessQueuedAccessRequest(content::WebContents *);

  // Called by the MediaObserver() functions, executed on UI thread.
  void updateAudioDevicesOnUIThread(const content::MediaStreamDevices &);
  void updateVideoDevicesOnUIThread(const content::MediaStreamDevices &);
  void updateMediaRequestStateOnUIThread(int renderProcessId, int renderViewId, int pageRequestId, const content::MediaStreamDevice &
                                         , content::MediaRequestState);

  // A list of cached audio capture devices.
  content::MediaStreamDevices m_audioDevices;

  // A list of cached video capture devices.
  content::MediaStreamDevices m_videoDevices;

  // Flag to indicate if device enumeration has been done/doing.
  // Only accessed on UI thread.
  bool m_devicesEnumerated;

  RequestsQueues m_pendingRequests;

  scoped_ptr<DesktopStreamsRegistry> m_desktopStreamsRegistry;

  content::NotificationRegistrar m_notificationsRegistrar;

  // Tracks MEDIA_DESKTOP_VIDEO_CAPTURE sessions which reach the
  // MEDIA_REQUEST_STATE_DONE state.  Sessions are remove when
  // MEDIA_REQUEST_STATE_CLOSING is encountered.
  struct DesktopCaptureSession {
    int render_process_id;
    int render_view_id;
    int page_request_id;
  };
  typedef std::list<DesktopCaptureSession> DesktopCaptureSessions;
  DesktopCaptureSessions m_desktopCaptureSessions;

  DISALLOW_COPY_AND_ASSIGN(MediaCaptureDevicesDispatcher);
};

#endif  // MEDIA_CAPTURE_DEVICES_DISPATCHER_H