On Fri, 2018-02-16 at 17:59 +0100, Christophe de Dinechin wrote:
> > On 16 Feb 2018, at 17:40, Frediano Ziglio <fzig...@redhat.com> wrote:
> >
> > >
> > > From: Christophe de Dinechin <dinec...@redhat.com>
> > >
> > > Get rid of C-style 'goto done' in do_capture.
> > > Get rid of global streamfd, pass it around (cleaned up in later patch)
> > > Fixes a race condition, make sure we only use stream after opening
> > >
> > > Signed-off-by: Christophe de Dinechin <dinec...@redhat.com>
> > > ---
> > > src/spice-streaming-agent.cpp | 79
> > > +++++++++++++++++++++++++------------------
> > > 1 file changed, 47 insertions(+), 32 deletions(-)
> > >
> > > diff --git a/src/spice-streaming-agent.cpp b/src/spice-streaming-agent.cpp
> > > index 646d15b..9b8fd45 100644
> > > --- a/src/spice-streaming-agent.cpp
> > > +++ b/src/spice-streaming-agent.cpp
> > > @@ -53,14 +53,38 @@ struct SpiceStreamDataMessage
> > > StreamMsgData msg;
> > > };
> > >
> > > +struct SpiceStreamCursorMessage
> > > +{
> > > + StreamDevHeader hdr;
> > > + StreamMsgCursorSet msg;
> > > +};
> > > +
> >
> > This is weird in this patch
>
> Yes. I may have merged two patches. Will check.
>
> >
> > > +class Stream
> > > +{
> > > +public:
> > > + Stream(const char *name)
> > > + {
> > > + fd = open(name, O_RDWR);
> > > + if (fd < 0)
> > > + throw std::runtime_error("failed to open streaming device");
Braces around if body (according to the coding style). Repeated a few
times below.
> > > + }
> > > + ~Stream()
> > > + {
> > > + close(fd);
> >
> > You probably what to check for -1 to avoid calling close(-1)
>
> I think this cannot happen, since in that case you’d have thrown from the
> ctor.
>
> >
> > > + }
> > > + operator int() { return fd; }
> >
> > Sure you want this? I think is safer to avoid implicit cast
> > also considering stuff like
> >
> > Stream s;
> > if (s) …
>
> It is removed in a later patch once it’s no longer needed. The objective here
> is to minimize noisy changes at each step.
I'd also rather not see it, but if it's removed later, no big deal.
> >
> > > +
> > > +private:
> > > + int fd = -1;
> >
> > So with a default constructor you want a class with
> > an invalid state?
> > Or just disable default constructor.
>
> It’s disabled, there’s a ctor with args.
>
> > I would disable also copy.
>
> Also implicitly disabled.
It is not, actually, disabled here. It gets disabled later when you add
the mutex member, as that is a non-copyable type.
It might be a good idea to explicitly delete the copy ctr/ao anyway...
In case someone ever removes the mutex and doesn't realize this.
> >
> > > +};
> > > +
> > > static bool streaming_requested = false;
> > > static bool quit_requested = false;
> > > static bool log_binary = false;
> > > static std::set<SpiceVideoCodecType> client_codecs;
> > > -static int streamfd = -1;
> > > static std::mutex stream_mtx;
> > >
> > > -static int have_something_to_read(int timeout)
> > > +static int have_something_to_read(int streamfd, int timeout)
> >
> > maybe would be better to use the "fd" name here, is no more
> > bound to stream.
>
> Kept to minimize changes
>
> > > {
> > > struct pollfd pollfd = {streamfd, POLLIN, 0};
> > >
> > > @@ -76,7 +100,7 @@ static int have_something_to_read(int timeout)
> > > return 0;
> > > }
> > >
> > > -static int read_command_from_device(void)
> > > +static int read_command_from_device(int streamfd)
> >
> > Have you considered Stream::read_command?
>
> For that specific case, I liked the “from_device”. But…
>
> > Ok, mostly in a following patch
>
>
> >
> > > {
> > > StreamDevHeader hdr;
> > > uint8_t msg[64];
> > > @@ -121,18 +145,18 @@ static int read_command_from_device(void)
> > > return 1;
> > > }
> > >
> > > -static int read_command(bool blocking)
> > > +static int read_command(int streamfd, bool blocking)
> > > {
> > > int timeout = blocking?-1:0;
> > > while (!quit_requested) {
> > > - if (!have_something_to_read(timeout)) {
> > > + if (!have_something_to_read(streamfd, timeout)) {
> > > if (!blocking) {
> > > return 0;
> > > }
> > > sleep(1);
> > > continue;
> > > }
> > > - return read_command_from_device();
> > > + return read_command_from_device(streamfd);
> > > }
> > >
> > > return 1;
> > > @@ -157,7 +181,7 @@ write_all(int fd, const void *buf, const size_t len)
> > > return written;
> > > }
> > >
> > > -static int spice_stream_send_format(unsigned w, unsigned h, unsigned c)
> > > +static int spice_stream_send_format(int streamfd, unsigned w, unsigned h,
> > > unsigned c)
> > > {
> > >
> > > SpiceStreamFormatMessage msg;
> > > @@ -178,7 +202,7 @@ static int spice_stream_send_format(unsigned w,
> > > unsigned
> > > h, unsigned c)
> > > return EXIT_SUCCESS;
> > > }
> > >
> > > -static int spice_stream_send_frame(const void *buf, const unsigned size)
> > > +static int spice_stream_send_frame(int streamfd, const void *buf, const
> > > unsigned size)
> > > {
> > > SpiceStreamDataMessage msg;
> > > const size_t msgsize = sizeof(msg);
> > > @@ -254,7 +278,7 @@ static void usage(const char *progname)
> > > }
> > >
> > > static void
> > > -send_cursor(unsigned width, unsigned height, int hotspot_x, int
> > > hotspot_y,
> > > +send_cursor(int streamfd, unsigned width, unsigned height, int hotspot_x,
> > > int hotspot_y,
> > > std::function<void(uint32_t *)> fill_cursor)
> > > {
> > > if (width >= STREAM_MSG_CURSOR_SET_MAX_WIDTH ||
> > > @@ -288,7 +312,7 @@ send_cursor(unsigned width, unsigned height, int
> > > hotspot_x, int hotspot_y,
> > > write_all(streamfd, msg.get(), cursor_size);
> > > }
> > >
> > > -static void cursor_changes(Display *display, int event_base)
> > > +static void cursor_changes(int streamfd, Display *display, int
> > > event_base)
> > > {
> > > unsigned long last_serial = 0;
> > >
> > > @@ -310,25 +334,20 @@ static void cursor_changes(Display *display, int
> > > event_base)
> > > for (unsigned i = 0; i < cursor->width * cursor->height; ++i)
> > > pixels[i] = cursor->pixels[i];
> > > };
> > > - send_cursor(cursor->width, cursor->height, cursor->xhot,
> > > cursor->yhot, fill_cursor);
> > > + send_cursor(streamfd,
> > > + cursor->width, cursor->height, cursor->xhot,
> > > cursor->yhot, fill_cursor);
> > > }
> > > }
> > >
> > > static void
> > > -do_capture(const char *streamport, FILE *f_log)
> > > +do_capture(int streamfd, const char *streamport, FILE *f_log)
> > > {
> > > - streamfd = open(streamport, O_RDWR);
> > > - if (streamfd < 0)
> > > - throw std::runtime_error("failed to open the streaming device ("
> > > +
> > > - std::string(streamport) + "): "
> > > - + strerror(errno));
> > > -
> > > unsigned int frame_count = 0;
> > > while (!quit_requested) {
> > > while (!quit_requested && !streaming_requested) {
> > > - if (read_command(true) < 0) {
> > > + if (read_command(streamfd, true) < 0) {
> > > syslog(LOG_ERR, "FAILED to read command\n");
> > > - goto done;
> > > + return;
> > > }
> > > }
> > >
> > > @@ -370,7 +389,7 @@ do_capture(const char *streamport, FILE *f_log)
> > >
> > > syslog(LOG_DEBUG, "wXh %uX%u codec=%u\n", width, height,
> > > codec);
> > >
> > > - if (spice_stream_send_format(width, height, codec) ==
> > > EXIT_FAILURE)
> > > + if (spice_stream_send_format(streamfd, width, height,
> > > codec)
> > > == EXIT_FAILURE)
> > > throw std::runtime_error("FAILED to send format
> > > message");
> > > }
> > > if (f_log) {
> > > @@ -382,23 +401,18 @@ do_capture(const char *streamport, FILE *f_log)
> > > hexdump(frame.buffer, frame.buffer_size, f_log);
> > > }
> > > }
> > > - if (spice_stream_send_frame(frame.buffer, frame.buffer_size)
> > > ==
> > > EXIT_FAILURE) {
> > > + if (spice_stream_send_frame(streamfd,
> > > + frame.buffer, frame.buffer_size)
> > > ==
> > > EXIT_FAILURE) {
> > > syslog(LOG_ERR, "FAILED to send a frame\n");
> > > break;
> > > }
> > > //usleep(1);
> > > - if (read_command(false) < 0) {
> > > + if (read_command(streamfd, 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__);
> > > @@ -481,12 +495,13 @@ int main(int argc, char* argv[])
> > > Window rootwindow = DefaultRootWindow(display);
> > > XFixesSelectCursorInput(display, rootwindow,
> > > XFixesDisplayCursorNotifyMask);
> > >
> > > - std::thread cursor_th(cursor_changes, display, event_base);
> > > + Stream streamfd(streamport);
Better call it 'stream', it's not just a fd anymore. Along with the
implicit conversion, this is quite confusing.
Lukas
> > > + std::thread cursor_th(cursor_changes, (int) streamfd, display,
> > > event_base);
> > > cursor_th.detach();
> > >
> > > int ret = EXIT_SUCCESS;
> > > try {
> > > - do_capture(streamport, f_log);
> > > + do_capture(streamfd, streamport, f_log);
> >
> > Not a fun of this implicit conversion
>
> Well, we can make it explicitl. But this is temporary, and is suppressed by
> the end of the series.
>
> > .
> >
> > > }
> > > catch (std::runtime_error &err) {
> > > syslog(LOG_ERR, "%s\n", err.what());
> >
> > Frediano
>
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