tablet-v2 tablet_pad grab implementation

Implement the basic logic for tablet-v2 tablet_pad's grabs. And plug in
the default grab.
Features like "holding" the focus should be implemented via grabs, like
they are for pointer and keyboard.

3 files changed, 196 insertions, 6 deletions

diff --git a/include/wlr/types/wlr_tablet_v2.h b/include/wlr/types/wlr_tablet_v2.h
index afa74d05..0b659f57 100644
--- a/include/wlr/types/wlr_tablet_v2.h
+++ b/include/wlr/types/wlr_tablet_v2.h
@@ -10,6 +10,14 @@
 /* This can probably be even lower,the tools don't have a lot of buttons */
 #define WLR_TABLET_V2_TOOL_BUTTONS_CAP 16
 
+struct wlr_tablet_pad_v2_grab_interface;
+
+struct wlr_tablet_pad_v2_grab {
+	const struct wlr_tablet_pad_v2_grab_interface *interface;
+	struct wlr_tablet_v2_tablet_pad *pad;
+	void *data;
+};
+
 struct wlr_tablet_client_v2;
 struct wlr_tablet_tool_client_v2;
 struct wlr_tablet_pad_client_v2;
@@ -70,6 +78,8 @@ struct wlr_tablet_v2_tablet_pad {
 	struct wl_listener pad_destroy;
 
 	struct wlr_tablet_pad_client_v2 *current_client;
+	struct wlr_tablet_pad_v2_grab *grab;
+	struct wlr_tablet_pad_v2_grab default_grab;
 
 	struct {
 		struct wl_signal button_feedback; // struct wlr_tablet_v2_event_feedback
@@ -155,7 +165,7 @@ void wlr_send_tablet_v2_tablet_pad_button(
 	struct wlr_tablet_v2_tablet_pad *pad, size_t button,
 	uint32_t time, enum zwp_tablet_pad_v2_button_state state);
 
-void wlr_send_tablet_v2_tablet_pad_strip( struct wlr_tablet_v2_tablet_pad *pad,
+void wlr_send_tablet_v2_tablet_pad_strip(struct wlr_tablet_v2_tablet_pad *pad,
 	uint32_t strip, double position, bool finger, uint32_t time);
 void wlr_send_tablet_v2_tablet_pad_ring(struct wlr_tablet_v2_tablet_pad *pad,
 	uint32_t ring, double position, bool finger, uint32_t time);
@@ -166,6 +176,56 @@ uint32_t wlr_send_tablet_v2_tablet_pad_leave(struct wlr_tablet_v2_tablet_pad *pa
 uint32_t wlr_send_tablet_v2_tablet_pad_mode(struct wlr_tablet_v2_tablet_pad *pad,
 	size_t group, uint32_t mode, uint32_t time);
 
+
+uint32_t wlr_tablet_v2_tablet_pad_notify_enter(
+	struct wlr_tablet_v2_tablet_pad *pad,
+	struct wlr_tablet_v2_tablet *tablet,
+	struct wlr_surface *surface);
+
+void wlr_tablet_v2_tablet_pad_notify_button(
+	struct wlr_tablet_v2_tablet_pad *pad, size_t button,
+	uint32_t time, enum zwp_tablet_pad_v2_button_state state);
+
+void wlr_tablet_v2_tablet_pad_notify_strip(
+	struct wlr_tablet_v2_tablet_pad *pad,
+	uint32_t strip, double position, bool finger, uint32_t time);
+void wlr_tablet_v2_tablet_pad_notify_ring(
+	struct wlr_tablet_v2_tablet_pad *pad,
+	uint32_t ring, double position, bool finger, uint32_t time);
+
+uint32_t wlr_tablet_v2_tablet_pad_notify_leave(
+	struct wlr_tablet_v2_tablet_pad *pad, struct wlr_surface *surface);
+
+uint32_t wlr_tablet_v2_tablet_pad_notify_mode(
+	struct wlr_tablet_v2_tablet_pad *pad,
+	size_t group, uint32_t mode, uint32_t time);
+
+struct wlr_tablet_pad_v2_grab_interface {
+	uint32_t (*enter)(
+		struct wlr_tablet_pad_v2_grab *grab,
+		struct wlr_tablet_v2_tablet *tablet,
+		struct wlr_surface *surface);
+
+	void (*button)(struct wlr_tablet_pad_v2_grab *grab,size_t button,
+		uint32_t time, enum zwp_tablet_pad_v2_button_state state);
+
+	void (*strip)(struct wlr_tablet_pad_v2_grab *grab,
+		uint32_t strip, double position, bool finger, uint32_t time);
+	void (*ring)(struct wlr_tablet_pad_v2_grab *grab,
+		uint32_t ring, double position, bool finger, uint32_t time);
+
+	uint32_t (*leave)(struct wlr_tablet_pad_v2_grab *grab,
+		struct wlr_surface *surface);
+
+	uint32_t (*mode)(struct wlr_tablet_pad_v2_grab *grab,
+		size_t group, uint32_t mode, uint32_t time);
+
+	void (*cancel)(struct wlr_tablet_pad_v2_grab *grab);
+};
+
+void wlr_tablet_v2_end_grab(struct wlr_tablet_v2_tablet_pad *pad);
+void wlr_tablet_v2_start_grab(struct wlr_tablet_v2_tablet_pad *pad, struct wlr_tablet_pad_v2_grab *grab);
+
 bool wlr_surface_accepts_tablet_v2(struct wlr_tablet_v2_tablet *tablet,
 	struct wlr_surface *surface);
 #endif /* WLR_TYPES_WLR_TABLET_V2_H */
diff --git a/rootston/seat.c b/rootston/seat.c
index 892faaa0..54aae49f 100644
--- a/rootston/seat.c
+++ b/rootston/seat.c
@@ -763,7 +763,7 @@ static void handle_tablet_pad_ring(struct wl_listener *listener, void *data) {
 		wl_container_of(listener, pad, ring);
 	struct wlr_event_tablet_pad_ring *event = data;
 
-	wlr_send_tablet_v2_tablet_pad_ring(pad->tablet_v2_pad,
+	wlr_tablet_v2_tablet_pad_notify_ring(pad->tablet_v2_pad,
 		event->ring, event->position,
 		event->source == WLR_TABLET_PAD_RING_SOURCE_FINGER,
 		event->time_msec);
@@ -774,7 +774,7 @@ static void handle_tablet_pad_strip(struct wl_listener *listener, void *data) {
 		wl_container_of(listener, pad, strip);
 	struct wlr_event_tablet_pad_strip *event = data;
 
-	wlr_send_tablet_v2_tablet_pad_strip(pad->tablet_v2_pad,
+	wlr_tablet_v2_tablet_pad_notify_strip(pad->tablet_v2_pad,
 		event->strip, event->position,
 		event->source == WLR_TABLET_PAD_STRIP_SOURCE_FINGER,
 		event->time_msec);
@@ -785,10 +785,10 @@ static void handle_tablet_pad_button(struct wl_listener *listener, void *data) {
 		wl_container_of(listener, pad, button);
 	struct wlr_event_tablet_pad_button *event = data;
 
-	wlr_send_tablet_v2_tablet_pad_mode(pad->tablet_v2_pad,
+	wlr_tablet_v2_tablet_pad_notify_mode(pad->tablet_v2_pad,
 		event->group, event->mode, event->time_msec);
 
-	wlr_send_tablet_v2_tablet_pad_button(pad->tablet_v2_pad,
+	wlr_tablet_v2_tablet_pad_notify_button(pad->tablet_v2_pad,
 		event->button, event->time_msec,
 		(enum zwp_tablet_pad_v2_button_state)event->state);
 }
@@ -1173,7 +1173,7 @@ void roots_seat_set_focus(struct roots_seat *seat, struct roots_view *view) {
 		struct roots_tablet_pad *pad;
 		wl_list_for_each(pad, &seat->tablet_pads, link) {
 			if (pad->tablet) {
-				wlr_send_tablet_v2_tablet_pad_enter(pad->tablet_v2_pad, pad->tablet->tablet_v2, view->wlr_surface);
+				wlr_tablet_v2_tablet_pad_notify_enter(pad->tablet_v2_pad, pad->tablet->tablet_v2, view->wlr_surface);
 			}
 		}
 	} else {
diff --git a/types/tablet_v2/wlr_tablet_v2_pad.c b/types/tablet_v2/wlr_tablet_v2_pad.c
index 1fcfa38e..b5b52939 100644
--- a/types/tablet_v2/wlr_tablet_v2_pad.c
+++ b/types/tablet_v2/wlr_tablet_v2_pad.c
@@ -11,6 +11,8 @@
 #include <wlr/types/wlr_tablet_v2.h>
 #include <wlr/util/log.h>
 
+static struct wlr_tablet_pad_v2_grab_interface default_pad_interface;
+
 struct tablet_pad_auxiliary_user_data {
 	struct wlr_tablet_pad_client_v2 *pad;
 	size_t index;
@@ -366,6 +368,9 @@ struct wlr_tablet_v2_tablet_pad *wlr_tablet_pad_create(
 	if (!pad) {
 		return NULL;
 	}
+	pad->default_grab.interface = &default_pad_interface;
+	pad->default_grab.pad = pad;
+	pad->grab = &pad->default_grab;
 
 	pad->group_count = wl_list_length(&wlr_pad->groups);
 	pad->groups = calloc(pad->group_count, sizeof(int));
@@ -564,3 +569,128 @@ bool wlr_surface_accepts_tablet_v2(struct wlr_tablet_v2_tablet *tablet,
 
 	return false;
 }
+
+
+uint32_t wlr_tablet_v2_tablet_pad_notify_enter(
+	struct wlr_tablet_v2_tablet_pad *pad,
+	struct wlr_tablet_v2_tablet *tablet,
+	struct wlr_surface *surface) {
+	if (pad->grab && pad->grab->interface->enter) {
+		return pad->grab->interface->enter(pad->grab, tablet, surface);
+	}
+
+	return 0;
+}
+
+void wlr_tablet_v2_tablet_pad_notify_button(
+	struct wlr_tablet_v2_tablet_pad *pad, size_t button,
+	uint32_t time, enum zwp_tablet_pad_v2_button_state state) {
+	if (pad->grab && pad->grab->interface->button) {
+		pad->grab->interface->button(pad->grab, button, time, state);
+	}
+}
+
+void wlr_tablet_v2_tablet_pad_notify_strip(
+	struct wlr_tablet_v2_tablet_pad *pad,
+	uint32_t strip, double position, bool finger, uint32_t time) {
+	if (pad->grab && pad->grab->interface->strip) {
+		pad->grab->interface->strip(pad->grab, strip, position, finger, time);
+	}
+}
+
+void wlr_tablet_v2_tablet_pad_notify_ring(
+	struct wlr_tablet_v2_tablet_pad *pad,
+	uint32_t ring, double position, bool finger, uint32_t time) {
+	if (pad->grab && pad->grab->interface->ring) {
+		pad->grab->interface->ring(pad->grab, ring, position, finger, time);
+	}
+}
+
+uint32_t wlr_tablet_v2_tablet_pad_notify_leave(
+	struct wlr_tablet_v2_tablet_pad *pad, struct wlr_surface *surface) {
+	if (pad->grab && pad->grab->interface->leave) {
+		return pad->grab->interface->leave(pad->grab, surface);
+	}
+
+	return 0;
+}
+
+uint32_t wlr_tablet_v2_tablet_pad_notify_mode(
+	struct wlr_tablet_v2_tablet_pad *pad,
+	size_t group, uint32_t mode, uint32_t time) {
+	if (pad->grab && pad->grab->interface->mode) {
+		return pad->grab->interface->mode(pad->grab, group, mode, time);
+	}
+
+	return 0;
+}
+
+void wlr_tablet_v2_start_grab(struct wlr_tablet_v2_tablet_pad *pad,
+		struct wlr_tablet_pad_v2_grab *grab) {
+	if (grab != &pad->default_grab) {
+		struct wlr_tablet_pad_v2_grab *prev = pad->grab;
+		grab->pad = pad;
+		pad->grab = grab;
+		if (prev) {
+			if (prev->interface->cancel) {
+				prev->interface->cancel(prev);
+			}
+		}
+	}
+}
+
+void wlr_tablet_v2_end_grab(struct wlr_tablet_v2_tablet_pad *pad) {
+	struct wlr_tablet_pad_v2_grab *grab = pad->grab;
+	if (grab && grab != &pad->default_grab) {
+		pad->grab = &pad->default_grab;
+		if (grab->interface->cancel) {
+			grab->interface->cancel(grab);
+		}
+	}
+}
+
+static uint32_t default_pad_enter(
+		struct wlr_tablet_pad_v2_grab *grab,
+		struct wlr_tablet_v2_tablet *tablet,
+		struct wlr_surface *surface) {
+	return wlr_send_tablet_v2_tablet_pad_enter(grab->pad, tablet, surface);
+}
+
+static void default_pad_button(struct wlr_tablet_pad_v2_grab *grab,size_t button,
+		uint32_t time, enum zwp_tablet_pad_v2_button_state state) {
+	wlr_send_tablet_v2_tablet_pad_button(grab->pad, button, time, state);
+}
+
+static void default_pad_strip(struct wlr_tablet_pad_v2_grab *grab,
+		uint32_t strip, double position, bool finger, uint32_t time) {
+	wlr_send_tablet_v2_tablet_pad_strip(grab->pad, strip, position, finger, time);
+}
+
+static void default_pad_ring(struct wlr_tablet_pad_v2_grab *grab,
+		uint32_t ring, double position, bool finger, uint32_t time) {
+	wlr_send_tablet_v2_tablet_pad_ring(grab->pad, ring, position, finger, time);
+}
+
+static uint32_t default_pad_leave(struct wlr_tablet_pad_v2_grab *grab,
+		struct wlr_surface *surface) {
+	return wlr_send_tablet_v2_tablet_pad_leave(grab->pad, surface);
+}
+
+static uint32_t default_pad_mode(struct wlr_tablet_pad_v2_grab *grab,
+		size_t group, uint32_t mode, uint32_t time) {
+	return wlr_send_tablet_v2_tablet_pad_mode(grab->pad, group, mode, time);
+}
+
+static void default_pad_cancel(struct wlr_tablet_pad_v2_grab *grab) {
+	// Do nothing, the default cancel can be ignored.
+}
+
+static struct wlr_tablet_pad_v2_grab_interface default_pad_interface  = {
+	.enter = default_pad_enter,
+	.button = default_pad_button,
+	.strip = default_pad_strip,
+	.ring = default_pad_ring,
+	.leave = default_pad_leave,
+	.mode = default_pad_mode,
+	.cancel = default_pad_cancel,
+};