[Spice-devel] [RFC PATCH spice-server v2 10/19] stream-channel: Allows to register callback to get new stream request

[Jonathon Jongsma]

On Wed, 2017-06-14 at 16:40 +0100, Frediano Ziglio wrote:
> The channel needs to communicate when it receive a new
> stream request from the guest.

I find it pretty odd to have a patch that introduces a callback that
can be registered without the callback ever being executed. It makes it
hard to know exactly how it's supposed to be used. Maybe this could be
combined with a later commit?

> 
> Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> ---
>  server/stream-channel.c | 12 ++++++++++++
>  server/stream-channel.h |  6 ++++++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/server/stream-channel.c b/server/stream-channel.c
> index 698a740..ae44f59 100644
> --- a/server/stream-channel.c
> +++ b/server/stream-channel.c
> @@ -67,6 +67,10 @@ struct StreamChannel {
>      int stream_id;
>      /* size of the current video stream */
>      unsigned width, height;
> +
> +    /* callback to notify when a stream should be started or stopped
> */
> +    stream_channel_start_proc start_cb;
> +    void *start_opaque;
>  };
>  
>  struct StreamChannelClass {
> @@ -379,3 +383,11 @@ stream_channel_send_data(StreamChannel *channel,
> const void *data, size_t size)
>      red_channel_pipes_new_add(red_channel, pipe_item_new_ref, item);
>      red_pipe_item_unref(&item->base);
>  }
> +
> +void
> +stream_channel_register_start_cb(StreamChannel *channel,
> +                                 stream_channel_start_proc cb, void
> *opaque)
> +{
> +    channel->start_cb = cb;
> +    channel->start_opaque = opaque;
> +}

For completeness, it would probably be good to include a 'free'
function for the opaque variable, but presumably for your use case,
none is needed.


> diff --git a/server/stream-channel.h b/server/stream-channel.h
> index b771082..d48c3c8 100644
> --- a/server/stream-channel.h
> +++ b/server/stream-channel.h
> @@ -49,11 +49,17 @@ GType stream_channel_get_type(void) G_GNUC_CONST;
>  StreamChannel* stream_channel_new(RedsState *server);
>  
>  struct StreamMsgFormat;
> +struct StreamMsgStartStop;
>  
>  void stream_channel_change_format(StreamChannel *channel,
>                                    const struct StreamMsgFormat
> *fmt);
>  void stream_channel_send_data(StreamChannel *channel, const void
> *data, size_t size);
>  
> +typedef void (*stream_channel_start_proc)(void *opaque, struct
> StreamMsgStartStop *start,
> +                                          StreamChannel *channel);
> +void stream_channel_register_start_cb(StreamChannel *channel,
> +                                      stream_channel_start_proc cb,
> void *opaque);
> +
>  G_END_DECLS
>  
>  #endif /* STREAM_CHANNEL_H_ */