[Spice-devel] [PATCH 08/14] Use RAII to cleanup stream in case of exception or return
Frediano Ziglio
fziglio at redhat.com
Thu Feb 15 10:04:02 UTC 2018
>
> 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>
I honestly prefer the "defer" style way.
Beside that you correctly pointed out that there's a race condition
on cursor thread which could lead the cursor thread to attempt writing
the cursor shape before the device is open and you proposed some fixes
in a different series.
I think would be a better fix for this.
> ---
> 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 25a38a6..e9ef310 100644
> --- a/src/spice-streaming-agent.cpp
> +++ b/src/spice-streaming-agent.cpp
> @@ -53,6 +53,23 @@ 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;
> +};
> +
> static bool streaming_requested = false;
> static bool quit_requested = false;
> static bool log_binary = false;
> @@ -354,17 +371,14 @@ static void cursor_changes(Display *display, int
> event_base)
> static void
> do_capture(const char *streamport, FILE *f_log)
> {
> - streamfd = open(streamport.c_str(), O_RDWR);
> - if (streamfd < 0)
> - throw std::runtime_error("failed to open the streaming device (" +
> - streamport + "): " + strerror(errno));
> + Stream stream(streamport, streamfd);
>
> unsigned int frame_count = 0;
> while (!quit_requested) {
> while (!quit_requested && !streaming_requested) {
> if (read_command(true) < 0) {
> syslog(LOG_ERR, "FAILED to read command\n");
> - goto done;
> + return;
> }
> }
>
> @@ -422,16 +436,10 @@ do_capture(const char *streamport, FILE *f_log)
> //usleep(1);
> if (read_command(false) < 0) {
> syslog(LOG_ERR, "FAILED to read command\n");
> - goto done;
> + return;
> }
> }
> }
> -
> -done:
> - if (streamfd >= 0) {
> - close(streamfd);
> - streamfd = -1;
> - }
> }
>
> #define arg_error(...) syslog(LOG_ERR, ## __VA_ARGS__);
Frediano
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