[PATCH libinput] touchpad: don't check clickfinger distance for three fingers

[Peter Hutterer]

It's reasonable to expect a thumb (or the other hand's index finger) to click
a button while a finger is down for movement. It's less reasonable to expect
this when two fingers are interacting with the touchpad, or when two fingers
click the touchpad (even on a large touchpad that's an awkward position).

Simplify the clickfinger detection mechanism - if we have three touches down,
it's always a three-finger click. Two fingers may be a right click or a index
+ thumb click.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/evdev-mt-touchpad-buttons.c | 23 ++++---------
 test/touchpad-buttons.c         | 74 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+), 17 deletions(-)

diff --git a/src/evdev-mt-touchpad-buttons.c b/src/evdev-mt-touchpad-buttons.c
index a2fb4b4..0e6426c 100644
--- a/src/evdev-mt-touchpad-buttons.c
+++ b/src/evdev-mt-touchpad-buttons.c
@@ -856,11 +856,9 @@ tp_clickfinger_set_button(struct tp_dispatch *tp)
 	unsigned int nfingers = tp->nfingers_down;
 	struct tp_touch *t;
 	struct tp_touch *first = NULL,
-			*second = NULL,
-			*third = NULL;
-	uint32_t close_touches = 0;
+			*second = NULL;
 
-	if (nfingers < 2 || nfingers > 3)
+	if (nfingers < 2 || nfingers >= 3)
 		goto out;
 
 	/* two or three fingers down on the touchpad. Check for distance
@@ -873,10 +871,6 @@ tp_clickfinger_set_button(struct tp_dispatch *tp)
 			first = t;
 		else if (!second)
 			second = t;
-		else if (!third) {
-			third = t;
-			break;
-		}
 	}
 
 	if (!first || !second) {
@@ -884,15 +878,10 @@ tp_clickfinger_set_button(struct tp_dispatch *tp)
 		goto out;
 	}
 
-	close_touches |= tp_check_clickfinger_distance(tp, first, second) << 0;
-	close_touches |= tp_check_clickfinger_distance(tp, second, third) << 1;
-	close_touches |= tp_check_clickfinger_distance(tp, first, third) << 2;
-
-	switch(__builtin_popcount(close_touches)) {
-	case 0: nfingers = 1; break;
-	case 1: nfingers = 2; break;
-	default: nfingers = 3; break;
-	}
+	if (tp_check_clickfinger_distance(tp, first, second))
+		nfingers = 2;
+	else
+		nfingers = 1;
 
 out:
 	switch (nfingers) {
diff --git a/test/touchpad-buttons.c b/test/touchpad-buttons.c
index ccc3b88..5767114 100644
--- a/test/touchpad-buttons.c
+++ b/test/touchpad-buttons.c
@@ -444,6 +444,78 @@ START_TEST(touchpad_2fg_clickfinger_distance)
 }
 END_TEST
 
+START_TEST(touchpad_3fg_clickfinger_distance)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+
+	if (libevdev_get_num_slots(dev->evdev) < 3)
+		return;
+
+	enable_clickfinger(dev);
+
+	litest_drain_events(li);
+
+	litest_touch_down(dev, 0, 90, 90);
+	litest_touch_down(dev, 1, 10, 15);
+	litest_touch_down(dev, 2, 10, 15);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+	litest_event(dev, EV_KEY, BTN_LEFT, 1);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+	litest_event(dev, EV_KEY, BTN_LEFT, 0);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+	litest_touch_up(dev, 0);
+	litest_touch_up(dev, 1);
+	litest_touch_up(dev, 2);
+
+	litest_assert_button_event(li,
+				   BTN_MIDDLE,
+				   LIBINPUT_BUTTON_STATE_PRESSED);
+	litest_assert_button_event(li,
+				   BTN_MIDDLE,
+				   LIBINPUT_BUTTON_STATE_RELEASED);
+}
+END_TEST
+
+START_TEST(touchpad_3fg_clickfinger_distance_btntool)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+
+	if (libevdev_get_num_slots(dev->evdev) > 2)
+		return;
+
+	enable_clickfinger(dev);
+
+	litest_drain_events(li);
+
+	litest_touch_down(dev, 0, 90, 90);
+	litest_touch_down(dev, 1, 10, 15);
+	libinput_dispatch(li);
+	litest_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, 0);
+	litest_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, 1);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+	libinput_dispatch(li);
+	litest_event(dev, EV_KEY, BTN_LEFT, 1);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+	litest_event(dev, EV_KEY, BTN_LEFT, 0);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+	litest_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, 1);
+	litest_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, 0);
+	litest_event(dev, EV_SYN, SYN_REPORT, 0);
+	litest_touch_up(dev, 0);
+	litest_touch_up(dev, 1);
+
+	litest_assert_button_event(li,
+				   BTN_MIDDLE,
+				   LIBINPUT_BUTTON_STATE_PRESSED);
+	litest_assert_button_event(li,
+				   BTN_MIDDLE,
+				   LIBINPUT_BUTTON_STATE_RELEASED);
+}
+END_TEST
+
 START_TEST(touchpad_2fg_clickfinger_bottom)
 {
 	struct litest_device *dev = litest_current_device();
@@ -1415,6 +1487,8 @@ litest_setup_tests(void)
 	litest_add("touchpad:clickfinger", touchpad_4fg_clickfinger_btntool_2slots, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:clickfinger", touchpad_4fg_clickfinger_btntool_3slots, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:clickfinger", touchpad_2fg_clickfinger_distance, LITEST_CLICKPAD, LITEST_ANY);
+	litest_add("touchpad:clickfinger", touchpad_3fg_clickfinger_distance, LITEST_CLICKPAD, LITEST_ANY);
+	litest_add("touchpad:clickfinger", touchpad_3fg_clickfinger_distance_btntool, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add_for_device("touchpad:clickfinger", touchpad_2fg_clickfinger_bottom, LITEST_SYNAPTICS_TOPBUTTONPAD);
 	litest_add("touchpad:clickfinger", touchpad_clickfinger_to_area_method, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:clickfinger",
-- 
2.4.3