seat/pointer: handle duplicate presses/releases correctly

backend/libinput/pointer.c

@@ -61,22 +61,12 @@ void handle_pointer_button(struct libinput_event *event,
 		.time_msec = usec_to_msec(libinput_event_pointer_get_time_usec(pevent)),
 		.button = libinput_event_pointer_get_button(pevent),
 	};
-	// Ignore events which aren't a seat-wide state change. For instance, if
-	// the same button is pressed twice on the same seat, ignore the second
-	// press.
-	uint32_t seat_count = libinput_event_pointer_get_seat_button_count(pevent);
 	switch (libinput_event_pointer_get_button_state(pevent)) {
 	case LIBINPUT_BUTTON_STATE_PRESSED:
 		wlr_event.state = WL_POINTER_BUTTON_STATE_PRESSED;
-		if (seat_count != 1) {
-			return;
-		}
 		break;
 	case LIBINPUT_BUTTON_STATE_RELEASED:
 		wlr_event.state = WL_POINTER_BUTTON_STATE_RELEASED;
-		if (seat_count != 0) {
-			return;
-		}
 		break;
 	}
 	wl_signal_emit_mutable(&pointer->events.button, &wlr_event);

include/wlr/types/wlr_seat.h

@@ -172,6 +172,11 @@ struct wlr_seat_pointer_grab {
 
 #define WLR_POINTER_BUTTONS_CAP 16
 
+struct wlr_seat_pointer_button {
+	uint32_t button;
+	size_t n_pressed;
+};
+
 struct wlr_seat_pointer_state {
 	struct wlr_seat *seat;
 	struct wlr_seat_client *focused_client;
@@ -184,8 +189,9 @@ struct wlr_seat_pointer_state {
 	bool sent_axis_source;
 	enum wl_pointer_axis_source cached_axis_source;
 
-	uint32_t buttons[WLR_POINTER_BUTTONS_CAP];
+	struct wlr_seat_pointer_button buttons[WLR_POINTER_BUTTONS_CAP];
 	size_t button_count;
+
 	uint32_t grab_button;
 	uint32_t grab_serial;
 	uint32_t grab_time;

types/seat/wlr_seat_pointer.c

@@ -6,7 +6,6 @@
 #include <wlr/types/wlr_compositor.h>
 #include <wlr/util/log.h>
 #include "types/wlr_seat.h"
-#include "util/set.h"
 
 static void default_pointer_enter(struct wlr_seat_pointer_grab *grab,
 		struct wlr_surface *surface, double sx, double sy) {
@@ -463,13 +462,37 @@ uint32_t wlr_seat_pointer_notify_button(struct wlr_seat *wlr_seat,
 			pointer_state->grab_button = button;
 			pointer_state->grab_time = time;
 		}
-		set_add(pointer_state->buttons, &pointer_state->button_count,
-			WLR_POINTER_BUTTONS_CAP, button);
+		for (size_t i = 0; i < pointer_state->button_count; i++) {
+			struct wlr_seat_pointer_button *pointer_button = &pointer_state->buttons[i];
+			if (pointer_button->button == button) {
+				++pointer_button->n_pressed;
+				return 0;
+			}
+		}
+		if (pointer_state->button_count == WLR_POINTER_BUTTONS_CAP) {
+			return 0;
+		}
+		pointer_state->buttons[pointer_state->button_count++] = (struct wlr_seat_pointer_button){
+			.button = button,
+			.n_pressed = 1,
+		};
 	} else {
-		set_remove(pointer_state->buttons, &pointer_state->button_count,
-			WLR_POINTER_BUTTONS_CAP, button);
+		bool found = false;
+		for (size_t i = 0; i < pointer_state->button_count; i++) {
+			struct wlr_seat_pointer_button *pointer_button = &pointer_state->buttons[i];
+			if (pointer_button->button == button) {
+				if (--pointer_button->n_pressed > 0) {
+					return 0;
+				}
+				*pointer_button = pointer_state->buttons[--pointer_state->button_count];
+				found = true;
+				break;
+			}
+		}
+		if (!found) {
+			return 0;
+		}
 	}
-
 
 	struct wlr_seat_pointer_grab *grab = pointer_state->grab;
 	uint32_t serial = grab->interface->button(grab, time, button, state);