[Spice-devel] [PATCH 07/17] Get rid of C-style memset initializations, use C++ style aggregates

[Lukáš Hrázký]

On Fri, 2018-02-16 at 17:15 +0100, Christophe de Dinechin wrote:
> From: Christophe de Dinechin <dinechin at redhat.com>
> 
> Signed-off-by: Christophe de Dinechin <dinechin at redhat.com>
> ---
>  src/spice-streaming-agent.cpp | 47 ++++++++++++++++++++++++++-----------------
>  1 file changed, 28 insertions(+), 19 deletions(-)
> 
> diff --git a/src/spice-streaming-agent.cpp b/src/spice-streaming-agent.cpp
> index 69c27a3..1e19e43 100644
> --- a/src/spice-streaming-agent.cpp
> +++ b/src/spice-streaming-agent.cpp
> @@ -181,19 +181,24 @@ write_all(int fd, const void *buf, const size_t len)
>      return written;
>  }
>  
> -static int spice_stream_send_format(int streamfd, unsigned w, unsigned h, unsigned c)
> +static int spice_stream_send_format(int streamfd, unsigned w, unsigned h, uint8_t c)
>  {
> -
> -    SpiceStreamFormatMessage msg;
> -    const size_t msgsize = sizeof(msg);
> -    const size_t hdrsize  = sizeof(msg.hdr);
> -    memset(&msg, 0, msgsize);
> -    msg.hdr.protocol_version = STREAM_DEVICE_PROTOCOL;
> -    msg.hdr.type = STREAM_TYPE_FORMAT;
> -    msg.hdr.size = msgsize - hdrsize; /* includes only the body? */
> -    msg.msg.width = w;
> -    msg.msg.height = h;
> -    msg.msg.codec = c;
> +    const size_t msgsize = sizeof(SpiceStreamFormatMessage);
> +    const size_t hdrsize  = sizeof(StreamDevHeader);
> +    SpiceStreamFormatMessage msg = {
> +        .hdr = {
> +            .protocol_version = STREAM_DEVICE_PROTOCOL,
> +            .padding = 0,       // Workaround GCC "not implemented" bug
> +            .type = STREAM_TYPE_FORMAT,
> +            .size = msgsize - hdrsize
> +        },
> +        .msg = {
> +            .width = w,
> +            .height = h,
> +            .codec = c,
> +            .padding1 = { }
> +        }
> +    };
>      syslog(LOG_DEBUG, "writing format\n");
>      std::lock_guard<std::mutex> stream_guard(stream_mtx);
>      if (write_all(streamfd, &msg, msgsize) != msgsize) {
> @@ -204,14 +209,18 @@ static int spice_stream_send_format(int streamfd, unsigned w, unsigned h, unsign
>  
>  static int spice_stream_send_frame(int streamfd, const void *buf, const unsigned size)
>  {
> -    SpiceStreamDataMessage msg;
> -    const size_t msgsize = sizeof(msg);
>      ssize_t n;
> +    const size_t msgsize = sizeof(SpiceStreamFormatMessage);
> +    SpiceStreamDataMessage msg = {
> +        .hdr = {
> +            .protocol_version = STREAM_DEVICE_PROTOCOL,
> +            .padding = 0,       // Workaround GCC "not implemented" bug
> +            .type = STREAM_TYPE_DATA,
> +            .size = size  /* includes only the body? */
> +        },
> +        .msg = {}
> +    };

So, someone should find out if we can use the designated initializers,
I suppose it depends on the compilers on all platforms we care about
supporting them?

I wasn't able to find much useful information so far. Anyone knows in
which version of gcc it was introduced?

Lukas

> -    memset(&msg, 0, msgsize);
> -    msg.hdr.protocol_version = STREAM_DEVICE_PROTOCOL;
> -    msg.hdr.type = STREAM_TYPE_DATA;
> -    msg.hdr.size = size; /* includes only the body? */
>      std::lock_guard<std::mutex> stream_guard(stream_mtx);
>      n = write_all(streamfd, &msg, msgsize);
>      syslog(LOG_DEBUG,
> @@ -379,7 +388,7 @@ do_capture(int streamfd, const char *streamport, FILE *f_log)
>  
>              if (frame.stream_start) {
>                  unsigned width, height;
> -                unsigned char codec;
> +                uint8_t codec;
>  
>                  width = frame.size.width;
>                  height = frame.size.height;