[Spice-devel] [RFC PATCH spice-server v3 11/20] stream-channel: Support client connection/disconnection

[Jonathon Jongsma]

Depending on your opinion of my comment on the last patch, this patch
could update a 'supported-codecs' property in connect/disconnect rather
than callin a request_new_stream() callback function. The code would be
fairly similar in the end, but it seems conceptually cleaner to me.

Reviewed-by: Jonathon Jongsma <jjongsma at redhat.com>


On Wed, 2017-08-23 at 10:14 +0100, Frediano Ziglio wrote:
> When a new client is connected we must restart the stream so new
> clients can receive correct data without having to wait for the
> next full screen (which on idle screen could take ages).
> On disconnection we should tell the guest to stop streaming
> not wasting resources to stream not needed data.
> 
> Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> ---
>  server/stream-channel.c | 77
> +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 77 insertions(+)
> 
> diff --git a/server/stream-channel.c b/server/stream-channel.c
> index a89a8f8e..7e3e8f07 100644
> --- a/server/stream-channel.c
> +++ b/server/stream-channel.c
> @@ -114,8 +114,32 @@ stream_channel_client_init(StreamChannelClient
> *client)
>  }
>  
>  static void
> +request_new_stream(StreamChannel *channel, StreamMsgStartStop
> *start)
> +{
> +    if (channel->start_cb) {
> +        channel->start_cb(channel->start_opaque, start, channel);
> +    }
> +}
> +
> +static void
>  stream_channel_client_on_disconnect(RedChannelClient *rcc)
>  {
> +    RedChannel *red_channel = red_channel_client_get_channel(rcc);
> +
> +    // if there are still some client connected keep streaming
> +    // TODO, maybe would be worth sending new codecs if they are
> better
> +    if (red_channel_is_connected(red_channel)) {
> +        return;
> +    }
> +
> +    StreamChannel *channel = STREAM_CHANNEL(red_channel);
> +    channel->stream_id = -1;
> +    channel->width = 0;
> +    channel->height = 0;
> +
> +    // send stream stop to device
> +    StreamMsgStartStop stop = { 0, };
> +    request_new_stream(channel, &stop);
>  }
>  
>  static StreamChannelClient*
> @@ -251,6 +275,51 @@ stream_channel_new(RedsState *server)
>                          NULL);
>  }
>  
> +// find common codecs supported by all clients
> +static StreamMsgStartStop*
> +stream_channel_get_supported_codecs(StreamChannel *channel)
> +{
> +    RedChannelClient *rcc;
> +    int codec;
> +
> +    static const uint16_t codec2cap[] = {
> +        0, // invalid
> +        SPICE_DISPLAY_CAP_CODEC_MJPEG,
> +        SPICE_DISPLAY_CAP_CODEC_VP8,
> +        SPICE_DISPLAY_CAP_CODEC_H264,
> +        SPICE_DISPLAY_CAP_CODEC_VP9,
> +    };
> +
> +    bool supported[SPICE_N_ELEMENTS(codec2cap)];
> +
> +    for (codec = 0; codec < SPICE_N_ELEMENTS(codec2cap); ++codec) {
> +        supported[codec] = true;
> +    }
> +
> +    FOREACH_CLIENT(channel, rcc) {
> +        for (codec = 1; codec < SPICE_N_ELEMENTS(codec2cap);
> ++codec) {
> +            // if do not support codec delete from list
> +            if (!red_channel_client_test_remote_cap(rcc,
> codec2cap[codec])) {
> +                supported[codec] = false;
> +            }
> +        }
> +    }
> +
> +    // surely mjpeg is supported
> +    supported[SPICE_VIDEO_CODEC_TYPE_MJPEG] = true;
> +
> +    StreamMsgStartStop *start = spice_malloc0(sizeof(*start) +
> sizeof(start->codecs[0]) * 256);
> +    int num = 0;
> +    for (codec = 1; codec < SPICE_N_ELEMENTS(codec2cap); ++codec) {
> +        if (supported[codec]) {
> +            start->codecs[num++] = codec;
> +        }
> +    }
> +    start->num_codecs = num;
> +
> +    return start;
> +}
> +
>  static void
>  stream_channel_connect(RedChannel *red_channel, RedClient
> *red_client, RedsStream *stream,
>                         int migration, RedChannelCapabilities *caps)
> @@ -263,6 +332,14 @@ stream_channel_connect(RedChannel *red_channel,
> RedClient *red_client, RedsStrea
>      client = stream_channel_client_new(channel, red_client, stream,
> migration, caps);
>      spice_return_if_fail(client != NULL);
>  
> +    // request new stream
> +    StreamMsgStartStop* start =
> stream_channel_get_supported_codecs(channel);
> +    // send in any case, even if list is not changed
> +    // notify device about changes
> +    request_new_stream(channel, start);
> +    free(start);
> +
> +
>      // TODO set capabilities like  SPICE_DISPLAY_CAP_MONITORS_CONFIG
>      // see guest_set_client_capabilities
>      RedChannelClient *rcc = RED_CHANNEL_CLIENT(client);