wlr-seat: pointer grab interface

include/wlr/types/wlr_seat.h

@@ -24,6 +24,30 @@ struct wlr_seat_handle {
 	struct wl_list link;
 };
 
+struct wlr_seat_pointer_grab;
+
+struct wlr_pointer_grab_interface {
+	void (*enter)(struct wlr_seat_pointer_grab *grab,
+			struct wlr_surface *surface, double sx, double sy);
+	void (*motion)(struct wlr_seat_pointer_grab *grab, uint32_t time,
+			double sx, double sy);
+	uint32_t (*button)(struct wlr_seat_pointer_grab *grab, uint32_t time,
+			uint32_t button, uint32_t state);
+	void (*axis)(struct wlr_seat_pointer_grab *grab, uint32_t time,
+			enum wlr_axis_orientation orientation, double value);
+	void (*cancel)(struct wlr_seat_pointer_grab *grab);
+};
+
+/**
+ * Passed to `wlr_seat_pointer_start_grab()` to start a grab of the pointer. The
+ * grabber is responsible for handling pointer events for the seat.
+ */
+struct wlr_seat_pointer_grab {
+	const struct wlr_pointer_grab_interface *interface;
+	struct wlr_seat *seat;
+	void *data;
+};
+
 struct wlr_seat_pointer_state {
 	struct wlr_seat *wlr_seat;
 	struct wlr_seat_handle *focused_handle;
@@ -31,6 +55,9 @@ struct wlr_seat_pointer_state {
 
 	struct wl_listener surface_destroy;
 	struct wl_listener resource_destroy;
+
+	struct wlr_seat_pointer_grab *grab;
+	struct wlr_seat_pointer_grab *default_grab;
 };
 
 struct wlr_seat_keyboard {
@@ -109,6 +136,8 @@ bool wlr_seat_pointer_surface_has_focus(struct wlr_seat *wlr_seat,
  * Send a pointer enter event to the given surface and consider it to be the
  * focused surface for the pointer. This will send a leave event to the last
  * surface that was entered. Coordinates for the enter event are surface-local.
+ * Compositor should use `wlr_seat_pointer_notify_enter()` to change pointer
+ * focus to respect pointer grabs.
  */
 void wlr_seat_pointer_enter(struct wlr_seat *wlr_seat,
 		struct wlr_surface *surface, double sx, double sy);
@@ -120,21 +149,71 @@ void wlr_seat_pointer_clear_focus(struct wlr_seat *wlr_seat);
 
 /**
  * Send a motion event to the surface with pointer focus. Coordinates for the
- * motion event are surface-local.
+ * motion event are surface-local. Compositors should use
+ * `wlr_seat_pointer_notify_motion()` to send motion events to respect pointer
+ * grabs.
  */
 void wlr_seat_pointer_send_motion(struct wlr_seat *wlr_seat, uint32_t time,
 		double sx, double sy);
 
 /**
  * Send a button event to the surface with pointer focus. Coordinates for the
- * button event are surface-local. Returns the serial.
+ * button event are surface-local. Returns the serial. Compositors should use
+ * `wlr_seat_pointer_notify_button()` to send button events to respect pointer
+ * grabs.
  */
 uint32_t wlr_seat_pointer_send_button(struct wlr_seat *wlr_seat, uint32_t time,
 		uint32_t button, uint32_t state);
 
+/**
+ * Send an axis event to the surface with pointer focus. Compositors should use
+ * `wlr_seat_pointer_notify_axis()` to send axis events to respect pointer
+ * grabs.
+ **/
 void wlr_seat_pointer_send_axis(struct wlr_seat *wlr_seat, uint32_t time,
 		enum wlr_axis_orientation orientation, double value);
 
+/**
+ * Start a grab of the pointer of this seat. The grabber is responsible for
+ * handling all pointer events until the grab ends.
+ */
+void wlr_seat_pointer_start_grab(struct wlr_seat *wlr_seat,
+		struct wlr_seat_pointer_grab *grab);
+
+/**
+ * End the grab of the pointer of this seat. This reverts the grab back to the
+ * default grab for the pointer.
+ */
+void wlr_seat_pointer_end_grab(struct wlr_seat *wlr_seat);
+
+/**
+ * Notify the seat of a pointer enter event to the given surface and request it to be the
+ * focused surface for the pointer. Pass surface-local coordinates where the
+ * enter occurred.
+ */
+void wlr_seat_pointer_notify_enter(struct wlr_seat *wlr_seat,
+		struct wlr_surface *surface, double sx, double sy);
+
+/**
+ * Notify the seat of motion over the given surface. Pass surface-local
+ * coordinates where the pointer motion occurred.
+ */
+void wlr_seat_pointer_notify_motion(struct wlr_seat *wlr_seat, uint32_t time,
+		double sx, double sy);
+
+/**
+ * Notify the seat that a button has been pressed. Returns the serial of the
+ * button press or zero if no button press was sent.
+ */
+uint32_t wlr_seat_pointer_notify_button(struct wlr_seat *wlr_seat,
+		uint32_t time, uint32_t button, uint32_t state);
+
+/**
+ * Notify the seat of an axis event.
+ */
+void wlr_seat_pointer_notify_axis(struct wlr_seat *wlr_seat, uint32_t time,
+		enum wlr_axis_orientation orientation, double value);
+
 /**
  * Attaches this keyboard to the seat. Key events from this keyboard will be
  * propegated to the focused client.

rootston/cursor.c

@@ -55,8 +55,8 @@ void cursor_update_position(struct roots_input *input, uint32_t time) {
 		view = view_at(desktop, input->cursor->x, input->cursor->y, &surface,
 			&sx, &sy);
 		if (view) {
-			wlr_seat_pointer_enter(input->wl_seat, surface, sx, sy);
+			wlr_seat_pointer_notify_enter(input->wl_seat, surface, sx, sy);
-			wlr_seat_pointer_send_motion(input->wl_seat, time, sx, sy);
+			wlr_seat_pointer_notify_motion(input->wl_seat, time, sx, sy);
 		} else {
 			wlr_seat_pointer_clear_focus(input->wl_seat);
 		}
@@ -137,7 +137,7 @@ static void handle_cursor_axis(struct wl_listener *listener, void *data) {
 	struct roots_input *input =
 		wl_container_of(listener, input, cursor_axis);
 	struct wlr_event_pointer_axis *event = data;
-	wlr_seat_pointer_send_axis(input->wl_seat, event->time_sec,
+	wlr_seat_pointer_notify_axis(input->wl_seat, event->time_sec,
 		event->orientation, event->delta);
 }
 
@@ -149,7 +149,7 @@ static void do_cursor_button_press(struct roots_input *input,
 	double sx, sy;
 	struct roots_view *view = view_at(desktop,
 			input->cursor->x, input->cursor->y, &surface, &sx, &sy);
-	uint32_t serial = wlr_seat_pointer_send_button(
+	uint32_t serial = wlr_seat_pointer_notify_button(
 			input->wl_seat, time, button, state);
 	int i;
 	switch (state) {

types/wlr_seat.c

@@ -173,6 +173,38 @@ static void wl_seat_bind(struct wl_client *wl_client, void *_wlr_seat,
 	wl_signal_emit(&wlr_seat->events.client_bound, handle);
 }
 
+static void default_pointer_enter(struct wlr_seat_pointer_grab *grab,
+			struct wlr_surface *surface, double sx, double sy) {
+	wlr_seat_pointer_enter(grab->seat, surface, sx, sy);
+}
+
+static void default_pointer_motion(struct wlr_seat_pointer_grab *grab,
+		uint32_t time, double sx, double sy) {
+	wlr_seat_pointer_send_motion(grab->seat, time, sx, sy);
+}
+
+static uint32_t default_pointer_button(struct wlr_seat_pointer_grab *grab,
+		uint32_t time, uint32_t button, uint32_t state) {
+	return wlr_seat_pointer_send_button(grab->seat, time, button, state);
+}
+
+static void default_pointer_axis(struct wlr_seat_pointer_grab *grab,
+		uint32_t time, enum wlr_axis_orientation orientation, double value) {
+	wlr_seat_pointer_send_axis(grab->seat, time, orientation, value);
+}
+
+static void default_pointer_cancel(struct wlr_seat_pointer_grab *grab) {
+	// cannot be cancelled
+}
+
+static const struct  wlr_pointer_grab_interface default_pointer_grab_impl = {
+	.enter = default_pointer_enter,
+	.motion = default_pointer_motion,
+	.button = default_pointer_button,
+	.axis = default_pointer_axis,
+	.cancel = default_pointer_cancel,
+};
+
 struct wlr_seat *wlr_seat_create(struct wl_display *display, const char *name) {
 	struct wlr_seat *wlr_seat = calloc(1, sizeof(struct wlr_seat));
 	if (!wlr_seat) {
@@ -183,6 +215,17 @@ struct wlr_seat *wlr_seat_create(struct wl_display *display, const char *name) {
 	wl_list_init(&wlr_seat->pointer_state.surface_destroy.link);
 	wl_list_init(&wlr_seat->pointer_state.resource_destroy.link);
 
+	struct wlr_seat_pointer_grab *default_grab =
+		calloc(1, sizeof(struct wlr_seat_pointer_grab));
+	if (!default_grab) {
+		free(wlr_seat);
+		return NULL;
+	}
+	default_grab->interface = &default_pointer_grab_impl;
+	default_grab->seat = wlr_seat;
+	wlr_seat->pointer_state.default_grab = default_grab;
+	wlr_seat->pointer_state.grab = default_grab;
+
 	wlr_seat->keyboard_state.wlr_seat = wlr_seat;
 	wl_list_init(&wlr_seat->keyboard_state.resource_destroy.link);
 	wl_list_init(
@@ -218,6 +261,7 @@ void wlr_seat_destroy(struct wlr_seat *wlr_seat) {
 	}
 
 	wl_global_destroy(wlr_seat->wl_global);
+	free(wlr_seat->pointer_state.default_grab);
 	free(wlr_seat->data_device);
 	free(wlr_seat->name);
 	free(wlr_seat);
@@ -386,6 +430,42 @@ void wlr_seat_pointer_send_axis(struct wlr_seat *wlr_seat, uint32_t time,
 	pointer_send_frame(pointer);
 }
 
+void wlr_seat_pointer_start_grab(struct wlr_seat *wlr_seat,
+		struct wlr_seat_pointer_grab *grab) {
+	grab->seat = wlr_seat;
+	wlr_seat->pointer_state.grab = grab;
+	// TODO: replay the last enter
+}
+
+void wlr_seat_pointer_end_grab(struct wlr_seat *wlr_seat) {
+	wlr_seat->pointer_state.grab = wlr_seat->pointer_state.default_grab;
+	// TODO: replay the last enter
+}
+
+void wlr_seat_pointer_notify_enter(struct wlr_seat *wlr_seat,
+		struct wlr_surface *surface, double sx, double sy) {
+	struct wlr_seat_pointer_grab *grab = wlr_seat->pointer_state.grab;
+	grab->interface->enter(grab, surface, sx, sy);
+}
+
+void wlr_seat_pointer_notify_motion(struct wlr_seat *wlr_seat, uint32_t time,
+		double sx, double sy) {
+	struct wlr_seat_pointer_grab *grab = wlr_seat->pointer_state.grab;
+	grab->interface->motion(grab, time, sx, sy);
+}
+
+uint32_t wlr_seat_pointer_notify_button(struct wlr_seat *wlr_seat,
+		uint32_t time, uint32_t button, uint32_t state) {
+	struct wlr_seat_pointer_grab *grab = wlr_seat->pointer_state.grab;
+	return grab->interface->button(grab, time, button, state);
+}
+
+void wlr_seat_pointer_notify_axis(struct wlr_seat *wlr_seat, uint32_t time,
+		enum wlr_axis_orientation orientation, double value) {
+	struct wlr_seat_pointer_grab *grab = wlr_seat->pointer_state.grab;
+	grab->interface->axis(grab, time, orientation, value);
+}
+
 static void keyboard_switch_seat_keyboard(struct wlr_seat_handle *handle,
 		struct wlr_seat_keyboard *seat_kb) {
 	if (handle->seat_keyboard == seat_kb) {