/// <summary>
/// Callback invoked after the native transceiver has been destroyed, for clean-up.
/// This is called by the peer connection when it closes, just before the C# transceiver
/// object instance is destroyed.
///
/// This replaces an hypothetical TransceiverRemoved callback, which doesn't exist to
/// prevent confusion and underline the fact transceiver cannot be removed after being
/// added to a peer connection, until that peer connection is closed and destroys them.
/// </summary>
internal void CleanUpAfterNativeDestroyed()
{
// The native peer connection was destroyed, therefore all its transceivers and remote
// tracks too, since it was owning them. However local tracks are owned by the user, so
// are possibly still alive.
Debug.Assert(!_nativeHandle.IsClosed);
Debug.Assert(_remoteTrack == null);
if (_localTrack != null)
{
Debug.Assert(_localTrack.Transceiver == this);
_localTrack.Transceiver = null;
_localTrack = null;
}
_nativeHandle.Dispose();
// No need (and can't) unregister callbacks, the native transceiver is already destroyed
Utils.ReleaseWrapperRef(_argsRef);
_argsRef = IntPtr.Zero;
}
/// <summary>
/// Change the local audio track sending data to the remote peer.
///
/// This detaches the previous local audio track if any, and attaches the new one instead.
/// Note that the transceiver will only send some audio data to the remote peer if its
/// negotiated direction includes sending some data and it has an attached local track to
/// produce this data.
///
/// This change is transparent to the session, and does not trigger any renegotiation.
/// </summary>
/// <param name="track">The new local audio track attached to the transceiver, and used to
/// produce audio data to send to the remote peer if the transceiver is sending.
/// Passing <c>null</c> is allowed, and will detach the current track if any.</param>
private void SetLocalTrackImpl(LocalMediaTrack track)
{
if (track == _localTrack)
{
return;
}
var audioTrack = (track as LocalAudioTrack);
var videoTrack = (track as LocalVideoTrack);
if ((audioTrack != null) && (MediaKind != MediaKind.Audio))
{
throw new ArgumentException("Cannot set local audio track as local track of video transceiver");
}
if ((videoTrack != null) && (MediaKind != MediaKind.Video))
{
throw new ArgumentException("Cannot set local video track as local track of audio transceiver");
}
if (track != null)
{
if ((track.PeerConnection != null) && (track.PeerConnection != PeerConnection))
{
throw new InvalidOperationException($"Cannot set track {track} of peer connection {track.PeerConnection} on transceiver {this} of different peer connection {PeerConnection}.");
}
uint res = Utils.MRS_E_UNKNOWN;
if (audioTrack != null)
{
res = TransceiverInterop.Transceiver_SetLocalAudioTrack(_nativeHandle, audioTrack._nativeHandle);
}
else if (videoTrack != null)
{
res = TransceiverInterop.Transceiver_SetLocalVideoTrack(_nativeHandle, videoTrack._nativeHandle);
}
Utils.ThrowOnErrorCode(res);
}
else
{
// Note: Cannot pass null for SafeHandle parameter value (ArgumentNullException)
uint res = Utils.MRS_E_UNKNOWN;
if (MediaKind == MediaKind.Audio)
{
res = TransceiverInterop.Transceiver_SetLocalAudioTrack(_nativeHandle, new LocalAudioTrackHandle());
}
else if (MediaKind == MediaKind.Video)
{
res = TransceiverInterop.Transceiver_SetLocalVideoTrack(_nativeHandle, new LocalVideoTrackHandle());
}
Utils.ThrowOnErrorCode(res);
}
// Remove old track
if (_localTrack != null)
{
Debug.Assert(_localTrack.Transceiver == this);
Debug.Assert(_localTrack.PeerConnection == PeerConnection);
_localTrack.Transceiver = null;
_localTrack.PeerConnection = null;
_localTrack = null;
}
// Add new track
if (track != null)
{
Debug.Assert(track.Transceiver == null);
Debug.Assert(track.PeerConnection == null);
_localTrack = track;
_localTrack.Transceiver = this;
_localTrack.PeerConnection = PeerConnection;
}
}