[Spice-devel] [PATCH spice-streaming-agent v2 3/4] Use RAII to cleanup stream in case of exception or return

[Frediano Ziglio]

> 
> From: Christophe de Dinechin <dinechin at redhat.com>
> 
> This lets us get rid of C-style 'goto done' in do_capture.
> 
> Signed-off-by: Christophe de Dinechin <dinechin at redhat.com>
> ---
>  src/spice-streaming-agent.cpp | 32 ++++++++++++++++++++------------
>  1 file changed, 20 insertions(+), 12 deletions(-)
> 
> diff --git a/src/spice-streaming-agent.cpp b/src/spice-streaming-agent.cpp
> index 1090517..8300cf2 100644
> --- a/src/spice-streaming-agent.cpp
> +++ b/src/spice-streaming-agent.cpp
> @@ -51,6 +51,23 @@ struct SpiceStreamDataMessage
>      StreamMsgData msg;
>  };
>  
> +struct Stream
> +{
> +  Stream(const char *name, int &fd): fd(fd)
> +  {
> +    fd = open(name, O_RDWR);
> +    if (fd < 0)
> +      throw std::runtime_error("failed to open streaming device");
> +  }
> +  ~Stream()
> +  {
> +    if (fd >= 0)
> +      close(fd);
> +    fd = -1;
> +  }
> +  int &fd;
> +};
> +

Maybe you want to disable copy.
Why you started indenting with 2 spaces instead of 4 ?

>  static int streaming_requested;
>  static bool quit;
>  static int streamfd = -1;
> @@ -349,17 +366,14 @@ do_capture(const char *streamport, FILE *f_log)
>      if (!capture)
>          throw std::runtime_error("cannot find a suitable capture system");
>  
> -    streamfd = open(streamport, O_RDWR);
> -    if (streamfd < 0)
> -        // TODO was syslog(LOG_ERR, "Failed to open %s: %s\n", streamport,
> strerror(errno));
> -        throw std::runtime_error("failed to open streaming device");
> +    Stream stream(streamport, streamfd);
>  
>      unsigned int frame_count = 0;
>      while (! quit) {
>          while (!quit && !streaming_requested) {
>              if (read_command(1) < 0) {
>                  syslog(LOG_ERR, "FAILED to read command\n");
> -                goto done;
> +                return;
>              }
>          }
>  
> @@ -410,19 +424,13 @@ do_capture(const char *streamport, FILE *f_log)
>              //usleep(1);
>              if (read_command(0) < 0) {
>                  syslog(LOG_ERR, "FAILED to read command\n");
> -                goto done;
> +                return;
>              }
>              if (!streaming_requested) {
>                  capture->Reset();
>              }
>          }
>      }
> -
> -done:
> -    if (streamfd >= 0) {
> -        close(streamfd);
> -        streamfd = -1;
> -    }
>  }
>  
>  #define arg_error(...) syslog(LOG_ERR, ## __VA_ARGS__);

Frediano