[PATCH libinput 2/2] Hook up event processing to libevdev

[Jonas Ådahl]

On Tue, Feb 18, 2014 at 04:09:10PM +1000, Peter Hutterer wrote:
> This gives us the ability to handle SYN_DROPPED transparently to the caller.
> 
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> ---
>  src/evdev.c | 90 +++++++++++++++++++++++++++++++++++++++----------------------
>  1 file changed, 58 insertions(+), 32 deletions(-)
> 
> diff --git a/src/evdev.c b/src/evdev.c
> index ba28fc6..836d0af 100644
> --- a/src/evdev.c
> +++ b/src/evdev.c
> @@ -29,7 +29,7 @@
>  #include <linux/input.h>
>  #include <unistd.h>
>  #include <fcntl.h>
> -#include <mtdev.h>
> +#include <mtdev-plumbing.h>
>  #include <assert.h>
>  
>  #include "libinput.h"
> @@ -436,56 +436,82 @@ fallback_dispatch_create(void)
>  	return dispatch;
>  }
>  
> -static void
> -evdev_process_events(struct evdev_device *device,
> -		     struct input_event *ev, int count)
> +static inline void
> +evdev_process_event(struct evdev_device *device, struct input_event *e)
>  {
>  	struct evdev_dispatch *dispatch = device->dispatch;
> -	struct input_event *e, *end;
> -	uint32_t time = 0;
> +	uint32_t time = e->time.tv_sec * 1000 + e->time.tv_usec / 1000;
>  
> -	e = ev;
> -	end = e + count;
> -	for (e = ev; e < end; e++) {
> -		time = e->time.tv_sec * 1000 + e->time.tv_usec / 1000;
> +	dispatch->interface->process(dispatch, device, e, time);
> +}
>  
> -		dispatch->interface->process(dispatch, device, e, time);
> +static inline void
> +evdev_device_dispatch_one(struct evdev_device *device,
> +			  struct input_event *ev)
> +{
> +	if (!device->mtdev) {
> +		evdev_process_event(device, ev);
> +	} else {
> +		mtdev_put_event(device->mtdev, ev);
> +		if (libevdev_event_is_code(ev, EV_SYN, SYN_REPORT)) {
> +			while(!mtdev_empty(device->mtdev)) {
> +				struct input_event e;
> +				mtdev_get_event(device->mtdev, &e);
> +				evdev_process_event(device, &e);
> +			}
> +		}
>  	}
>  }
>  
> +static int
> +evdev_sync_device(struct evdev_device *device)
> +{
> +	struct input_event ev;
> +	int rc;
> +
> +	do {
> +		rc = libevdev_next_event(device->evdev,
> +					 LIBEVDEV_READ_FLAG_SYNC, &ev);
> +		if (rc < 0)
> +			break;
> +		evdev_device_dispatch_one(device, &ev);
> +	} while (rc == LIBEVDEV_READ_STATUS_SYNC);
> +
> +	return rc == -EAGAIN ? 0 : rc;
> +}
> +
>  static void
>  evdev_device_dispatch(void *data)
>  {
>  	struct evdev_device *device = data;
>  	struct libinput *libinput = device->base.seat->libinput;
> -	int fd = device->fd;
> -	struct input_event ev[32];
> -	int len;
> +	struct input_event ev;
> +	int rc;
>  
>  	/* If the compositor is repainting, this function is called only once
>  	 * per frame and we have to process all the events available on the
>  	 * fd, otherwise there will be input lag. */
>  	do {
> -		if (device->mtdev)
> -			len = mtdev_get(device->mtdev, fd, ev,
> -					ARRAY_LENGTH(ev)) *
> -				sizeof (struct input_event);
> -		else
> -			len = read(fd, &ev, sizeof ev);
> +		rc = libevdev_next_event(device->evdev,
> +					 LIBEVDEV_READ_FLAG_NORMAL, &ev);
> +		if (rc == LIBEVDEV_READ_STATUS_SYNC) {
> +			/* send one more sync event so we handle all
> +			   currently pending events before we sync up
> +			   to the current state */
> +			ev.code = SYN_REPORT;
> +			evdev_device_dispatch_one(device, &ev);

Is this really correct? Shouldn't calling libevdev_next_event() in SYNC
mode return a SYN_REPORT event as part of the synchronization? If we do
like this it looks like we might "cut" one series of events that would
otherwise be grouped using SYN_REPORT in half.

>  
> -		if (len < 0 || len % sizeof ev[0] != 0) {
> -			if (len < 0 && errno != EAGAIN && errno != EINTR) {
> -				libinput_remove_source(libinput,
> -						       device->source);
> -				device->source = NULL;
> -			}
> +			rc = evdev_sync_device(device);
> +			if (rc == 0)
> +				rc = LIBEVDEV_READ_STATUS_SUCCESS;
> +		} else if (rc == LIBEVDEV_READ_STATUS_SUCCESS)
> +			evdev_device_dispatch_one(device, &ev);

nit: if any branch of an if have braces, all should.

> +	} while (rc == LIBEVDEV_READ_STATUS_SUCCESS);
>  
> -			return;
> -		}
> -
> -		evdev_process_events(device, ev, len / sizeof ev[0]);
> -
> -	} while (len > 0);
> +	if (rc != -EAGAIN && rc != -EINTR) {
> +		libinput_remove_source(libinput, device->source);
> +		device->source = NULL;
> +	}
>  }
>  
>  static int
> -- 
> 1.8.4.2


Jonas