[PATCH libinput 1/4] evdev: Ignore key/button release events if key was never pressed
Jonas Ådahl
jadahl at gmail.com
Mon Jul 28 01:04:35 PDT 2014
On Mon, Jul 28, 2014 at 09:48:05AM +0300, Ran Benita wrote:
> Hi Jonas,
>
> On Sun, Jul 27, 2014 at 11:28:28PM +0200, Jonas Ådahl wrote:
> > The kernel may send a 'release' event without ever having sent a key
> > 'pressed' event in case the key was pressed before libinput was
> > initiated. Ignore these events so that we always guarantee a release
> > event always comes after a pressed event for any given key or button.
>
> Would it be possible to describe in the docs the invariants that
> libinput is keeping w.r.t. key press/release ordering and count?
> If the user can rely on such invariants, it can simplify how he
> interfaces with e.g. libxkbcommon, which expects a coherent key event
> stream (things like modifier press with a missed release can cause some
> fun).
Yea, I will send another patch documenting it. My plan is that libinput
will guarantee that for any device, 'pressed' always predates a
'released' and ever only one 'pressed' or 'released' in a row for any
given key, including when devices are plugged in or out, or when
suspending and resuming a libinput context. That should play along well
with libxkbcommon without any extra button/key state tracking in between
libinput and libxkbcommon.
Note that the user still needs to multiplex multiple devices into a
virtual per seat "core" device, but libinput helps with tracking that
state for us as well by also counting button presses per seat.
Jonas
>
> Ran
>
> > Signed-off-by: Jonas Ådahl <jadahl at gmail.com>
> > ---
> > src/evdev.c | 33 ++++++++++++++++++++++++++++++++-
> > src/evdev.h | 2 ++
> > src/libinput-util.h | 29 +++++++++++++++++++++++++++++
> > test/keyboard.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 115 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/evdev.c b/src/evdev.c
> > index 5872856..0f4874c 100644
> > --- a/src/evdev.c
> > +++ b/src/evdev.c
> > @@ -47,6 +47,18 @@ enum evdev_key_type {
> > EVDEV_KEY_TYPE_BUTTON,
> > };
> >
> > +static void
> > +set_key_pressed(struct evdev_device *device, int code, int pressed)
> > +{
> > + long_set_bit_state(device->key_mask, code, pressed);
> > +}
> > +
> > +static int
> > +is_key_pressed(struct evdev_device *device, int code)
> > +{
> > + return long_bit_is_set(device->key_mask, code);
> > +}
> > +
> > void
> > evdev_device_led_update(struct evdev_device *device, enum libinput_led leds)
> > {
> > @@ -294,6 +306,8 @@ static inline void
> > evdev_process_key(struct evdev_device *device,
> > struct input_event *e, uint64_t time)
> > {
> > + enum evdev_key_type type;
> > +
> > /* ignore kernel key repeat */
> > if (e->value == 2)
> > return;
> > @@ -306,7 +320,24 @@ evdev_process_key(struct evdev_device *device,
> >
> > evdev_flush_pending_event(device, time);
> >
> > - switch (get_key_type(e->code)) {
> > + type = get_key_type(e->code);
> > +
> > + /* Ignore key release events from the kernel for keys that libinput
> > + * never got a pressed event for. */
> > + if (e->value == 0) {
> > + switch (type) {
> > + case EVDEV_KEY_TYPE_NONE:
> > + break;
> > + case EVDEV_KEY_TYPE_KEY:
> > + case EVDEV_KEY_TYPE_BUTTON:
> > + if (!is_key_pressed(device, e->code))
> > + return;
> > + }
> > + }
> > +
> > + set_key_pressed(device, e->code, e->value);
> > +
> > + switch (type) {
> > case EVDEV_KEY_TYPE_NONE:
> > break;
> > case EVDEV_KEY_TYPE_KEY:
> > diff --git a/src/evdev.h b/src/evdev.h
> > index fad1f84..f71d387 100644
> > --- a/src/evdev.h
> > +++ b/src/evdev.h
> > @@ -94,6 +94,8 @@ struct evdev_device {
> > struct {
> > struct motion_filter *filter;
> > } pointer;
> > +
> > + unsigned long key_mask[NLONGS(KEY_CNT)];
> > };
> >
> > #define EVDEV_UNHANDLED_DEVICE ((struct evdev_device *) 1)
> > diff --git a/src/libinput-util.h b/src/libinput-util.h
> > index c0235ef..2f1a1db 100644
> > --- a/src/libinput-util.h
> > +++ b/src/libinput-util.h
> > @@ -72,6 +72,8 @@ int list_empty(const struct list *list);
> > pos = tmp, \
> > tmp = container_of(pos->member.next, tmp, member))
> >
> > +#define LONG_BITS (sizeof(long) * 8)
> > +#define NLONGS(x) (((x) + LONG_BITS - 1) / LONG_BITS)
> > #define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
> > #define ARRAY_FOR_EACH(_arr, _elem) \
> > for (size_t _i = 0; (_elem = &_arr[_i]) && _i < ARRAY_LENGTH(_arr); _i++)
> > @@ -150,4 +152,31 @@ vector_get_direction(int dx, int dy)
> > return dir;
> > }
> >
> > +static inline int
> > +long_bit_is_set(const unsigned long *array, int bit)
> > +{
> > + return !!(array[bit / LONG_BITS] & (1LL << (bit % LONG_BITS)));
> > +}
> > +
> > +static inline void
> > +long_set_bit(unsigned long *array, int bit)
> > +{
> > + array[bit / LONG_BITS] |= (1LL << (bit % LONG_BITS));
> > +}
> > +
> > +static inline void
> > +long_clear_bit(unsigned long *array, int bit)
> > +{
> > + array[bit / LONG_BITS] &= ~(1LL << (bit % LONG_BITS));
> > +}
> > +
> > +static inline void
> > +long_set_bit_state(unsigned long *array, int bit, int state)
> > +{
> > + if (state)
> > + long_set_bit(array, bit);
> > + else
> > + long_clear_bit(array, bit);
> > +}
> > +
> > #endif /* LIBINPUT_UTIL_H */
> > diff --git a/test/keyboard.c b/test/keyboard.c
> > index a55405c..a7f500c 100644
> > --- a/test/keyboard.c
> > +++ b/test/keyboard.c
> > @@ -112,10 +112,62 @@ START_TEST(keyboard_seat_key_count)
> > }
> > END_TEST
> >
> > +START_TEST(keyboard_ignore_no_pressed_release)
> > +{
> > + struct litest_device *dev;
> > + struct libinput *libinput;
> > + struct libinput_event *event;
> > + struct libinput_event_keyboard *kevent;
> > + int events[] = {
> > + EV_KEY, KEY_A,
> > + -1, -1,
> > + };
> > + enum libinput_key_state *state;
> > + enum libinput_key_state expected_states[] = {
> > + LIBINPUT_KEY_STATE_PRESSED,
> > + LIBINPUT_KEY_STATE_RELEASED,
> > + };
> > +
> > +
> > + libinput = litest_create_context();
> > + dev = litest_add_device_with_overrides(libinput,
> > + LITEST_KEYBOARD,
> > + "Generic keyboard",
> > + NULL, NULL, events);
> > +
> > + litest_drain_events(libinput);
> > +
> > + litest_keyboard_key(dev, KEY_A, false);
> > + litest_keyboard_key(dev, KEY_A, true);
> > + litest_keyboard_key(dev, KEY_A, false);
> > +
> > + libinput_dispatch(libinput);
> > +
> > + ARRAY_FOR_EACH(expected_states, state) {
> > + event = libinput_get_event(libinput);
> > + ck_assert_notnull(event);
> > + ck_assert_int_eq(libinput_event_get_type(event),
> > + LIBINPUT_EVENT_KEYBOARD_KEY);
> > + kevent = libinput_event_get_keyboard_event(event);
> > + ck_assert_int_eq(libinput_event_keyboard_get_key(kevent),
> > + KEY_A);
> > + ck_assert_int_eq(libinput_event_keyboard_get_key_state(kevent),
> > + *state);
> > + libinput_event_destroy(event);
> > + libinput_dispatch(libinput);
> > + }
> > +
> > + litest_assert_empty_queue(libinput);
> > + litest_delete_device(dev);
> > + libinput_unref(libinput);
> > +}
> > +END_TEST
> > +
> > int
> > main(int argc, char **argv)
> > {
> > litest_add_no_device("keyboard:seat key count", keyboard_seat_key_count);
> > + litest_add_no_device("keyboard:ignore no pressed release", keyboard_ignore_no_pressed_release);
> >
> > return litest_run(argc, argv);
> > }
> > --
> > 1.8.5.1
> >
> > _______________________________________________
> > wayland-devel mailing list
> > wayland-devel at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/wayland-devel
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