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#ifndef MEDIA_CAPTURE_DEVICES_DISPATCHER_H
#define MEDIA_CAPTURE_DEVICES_DISPATCHER_H

#include <deque>
#include <list>
#include <map>

#include "web_contents_adapter_client.h"

#include "base/callback.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 DesktopStreamsRegistry;

namespace QtWebEngineCore {

// 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:
  void OnAudioCaptureDevicesChanged() override { }
  void OnVideoCaptureDevicesChanged() override { }
  void OnMediaRequestStateChanged(int render_process_id,
                                  int render_frame_id,
                                  int page_request_id,
                                  const GURL& security_origin,
                                  content::MediaStreamType stream_type,
                                  content::MediaRequestState state) override;

  void OnCreatingAudioStream(int /*render_process_id*/, int /*render_frame_id*/) override { }
  void OnSetCapturingLinkSecured(int /*render_process_id*/,
                                 int /*render_frame_id*/,
                                 int /*page_request_id*/,
                                 content::MediaStreamType /*stream_type*/,
                                 bool /*is_secure*/) override { }

  DesktopStreamsRegistry *getDesktopStreamsRegistry();

 private:
  friend struct base::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();

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

  // Helpers for ProcessMediaAccessRequest().
  void processDesktopCaptureAccessRequest(content::WebContents *, const content::MediaStreamRequest &, const content::MediaResponseCallback &);
  void enqueueMediaAccessRequest(content::WebContents *, const content::MediaStreamRequest &, const content::MediaResponseCallback &);
  void ProcessQueuedAccessRequest(content::WebContents *);

  // Called by the MediaObserver() functions, executed on UI thread.
  void updateMediaRequestStateOnUIThread(int render_process_id, int render_frame_id, int page_request_id, const GURL& security_origin, content::MediaStreamType stream_type, content::MediaRequestState state);

  RequestsQueues m_pendingRequests;

  std::unique_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);
};

} // namespace QtWebEngineCore

#endif  // MEDIA_CAPTURE_DEVICES_DISPATCHER_H
