[PATCH libevdev] Store the abs value after handling mt events

[Peter Hutterer]

This way any ABS_MT_ event value that comes in will also be stored in abs_info.
That always corresponds to "current slot", so if a user calls
libevdev_set_event_value() or libevdev_get_event_value() they're actually
modifying the current slot value.

When the current slot changes, sync the state back into the absinfo values.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
follow-up to patch 3/7, this brings the expected behaviour and symmetry for
libevdev_get/set_event_value.

 libevdev/libevdev.c         |  9 +++++++-
 libevdev/libevdev.h         |  8 +++++++
 test/test-libevdev-events.c | 54 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/libevdev/libevdev.c b/libevdev/libevdev.c
index 4dc3ccc..cea33e6 100644
--- a/libevdev/libevdev.c
+++ b/libevdev/libevdev.c
@@ -507,7 +507,14 @@ static int
 update_mt_state(struct libevdev *dev, const struct input_event *e)
 {
 	if (e->code == ABS_MT_SLOT) {
+		int i;
 		dev->current_slot = e->value;
+		/* sync abs_info with the current slot values */
+		for (i = ABS_MT_SLOT + 1; i <= ABS_MT_MAX; i++) {
+			if (libevdev_has_event_code(dev, EV_ABS, i))
+				dev->abs_info[i].value = dev->mt_slot_vals[dev->current_slot][i - ABS_MT_MIN];
+		}
+
 		return 0;
 	} else if (dev->current_slot == -1)
 		return 1;
@@ -527,7 +534,7 @@ update_abs_state(struct libevdev *dev, const struct input_event *e)
 		return 1;
 
 	if (e->code >= ABS_MT_MIN && e->code <= ABS_MT_MAX)
-		return update_mt_state(dev, e);
+		update_mt_state(dev, e);
 
 	dev->abs_info[e->code].value = e->value;
 
diff --git a/libevdev/libevdev.h b/libevdev/libevdev.h
index de7182a..9864292 100644
--- a/libevdev/libevdev.h
+++ b/libevdev/libevdev.h
@@ -799,6 +799,10 @@ const struct input_absinfo* libevdev_get_abs_info(const struct libevdev *dev, un
  * Behaviour of this function is undefined if the device does not provide
  * the event.
  *
+ * If the device supports ABS_MT_SLOT, the value returned for any ABS_MT_*
+ * event code is the value of the currently active slot. You should use
+ * libevdev_get_slot_value() instead.
+ *
  * @param dev The evdev device, already initialized with libevdev_set_fd()
  * @param type The event type for the code to query (EV_SYN, EV_REL, etc.)
  * @param code The event code to query for, one of ABS_X, REL_X, etc.
@@ -823,6 +827,10 @@ int libevdev_get_event_value(const struct libevdev *dev, unsigned int type, unsi
  * this device. A future call to libevdev_get_event_value() will return this
  * value, unless the value was overwritten by an event.
  *
+ * If the device supports ABS_MT_SLOT, the value set for any ABS_MT_*
+ * event code is the value of the currently active slot. You should use
+ * libevdev_set_slot_value() instead.
+ *
  * @param dev The evdev device, already initialized with libevdev_set_fd()
  * @param type The event type for the code to query (EV_SYN, EV_REL, etc.)
  * @param code The event code to set the value for, one of ABS_X, LED_NUML, etc.
diff --git a/test/test-libevdev-events.c b/test/test-libevdev-events.c
index afa426d..669de12 100644
--- a/test/test-libevdev-events.c
+++ b/test/test-libevdev-events.c
@@ -1033,6 +1033,59 @@ START_TEST(test_event_mt_value_setters_invalid)
 }
 END_TEST
 
+START_TEST(test_event_mt_value_setters_current_slot)
+{
+	struct uinput_device* uidev;
+	struct libevdev *dev;
+	int rc;
+	struct input_absinfo abs[5];
+
+	memset(abs, 0, sizeof(abs));
+	abs[0].value = ABS_X;
+	abs[0].maximum = 1000;
+	abs[1].value = ABS_MT_POSITION_X;
+	abs[1].maximum = 1000;
+
+	abs[2].value = ABS_Y;
+	abs[2].maximum = 1000;
+	abs[3].value = ABS_MT_POSITION_Y;
+	abs[3].maximum = 1000;
+
+	abs[4].value = ABS_MT_SLOT;
+	abs[4].maximum = 2;
+
+	rc = test_create_abs_device(&uidev, &dev,
+				    5, abs,
+				    EV_SYN, SYN_REPORT,
+				    -1);
+	ck_assert_msg(rc == 0, "Failed to create device: %s", strerror(-rc));
+
+	/* set_event_value/get_event_value works on the current slot */
+
+	ck_assert_int_eq(libevdev_get_current_slot(dev), 0);
+	ck_assert_int_eq(libevdev_set_event_value(dev, EV_ABS, ABS_MT_POSITION_X, 1), 0);
+	ck_assert_int_eq(libevdev_get_event_value(dev, EV_ABS, ABS_MT_POSITION_X), 1);
+	ck_assert_int_eq(libevdev_get_slot_value(dev, 0, ABS_MT_POSITION_X), 1);
+
+	ck_assert_int_eq(libevdev_set_event_value(dev, EV_ABS, ABS_MT_SLOT, 1), 0);
+	ck_assert_int_eq(libevdev_get_current_slot(dev), 1);
+	ck_assert_int_eq(libevdev_set_event_value(dev, EV_ABS, ABS_MT_POSITION_X, 2), 0);
+	ck_assert_int_eq(libevdev_get_event_value(dev, EV_ABS, ABS_MT_POSITION_X), 2);
+	ck_assert_int_eq(libevdev_get_slot_value(dev, 1, ABS_MT_POSITION_X), 2);
+
+	/* set slot 0, but current is still slot 1 */
+	ck_assert_int_eq(libevdev_set_slot_value(dev, 0, ABS_MT_POSITION_X, 3), 0);
+	ck_assert_int_eq(libevdev_get_event_value(dev, EV_ABS, ABS_MT_POSITION_X), 2);
+
+	ck_assert_int_eq(libevdev_set_event_value(dev, EV_ABS, ABS_MT_SLOT, 0), 0);
+	ck_assert_int_eq(libevdev_get_current_slot(dev), 0);
+	ck_assert_int_eq(libevdev_get_event_value(dev, EV_ABS, ABS_MT_POSITION_X), 3);
+
+	uinput_device_free(uidev);
+	libevdev_free(dev);
+}
+END_TEST
+
 Suite *
 libevdev_events(void)
 {
@@ -1071,6 +1124,7 @@ libevdev_events(void)
 	tcase_add_test(tc, test_event_value_setters_invalid);
 	tcase_add_test(tc, test_event_mt_value_setters);
 	tcase_add_test(tc, test_event_mt_value_setters_invalid);
+	tcase_add_test(tc, test_event_mt_value_setters_current_slot);
 	suite_add_tcase(s, tc);
 
 	return s;
-- 
1.8.2.1