cursor: Restore drag icon after the move to scene-graph

Also move everything DnD related to src/dnd.c

include/dnd.h

@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __LAB_DND_H
+#define __LAB_DND_H
+
+#include <wayland-server-core.h>
+
+struct seat;
+struct wlr_drag_icon;
+struct wlr_scene_tree;
+
+struct drag_icon {
+	struct wlr_scene_tree *icon_tree;
+	struct wlr_drag_icon *icon;
+	struct {
+		struct wl_listener map;
+		struct wl_listener commit;
+		struct wl_listener unmap;
+		struct wl_listener destroy;
+	} events;
+};
+
+void dnd_init(struct seat *seat);
+void dnd_icons_show(struct seat *seat, bool show);
+void dnd_icons_move(struct seat *seat, double x, double y);
+void dnd_finish(struct seat *seat);
+
+#endif /* __LAB_DND_H */

include/labwc.h

@@ -104,7 +104,6 @@ struct seat {
 	struct wlr_cursor *cursor;
 	struct wlr_xcursor_manager *xcursor_manager;
 
-	struct wlr_drag_icon *drag_icon;
 	struct wlr_pointer_constraint_v1 *current_constraint;
 	struct wlr_idle *wlr_idle;
 	struct wlr_idle_inhibit_manager_v1 *wlr_idle_inhibit_manager;
@@ -136,6 +135,16 @@ struct seat {
 		uint32_t resize_edges;
 	} pressed;
 
+	struct {
+		bool active;
+		struct {
+			struct wl_listener request;
+			struct wl_listener start;
+			struct wl_listener destroy;
+		} events;
+		struct wlr_scene_tree *icons;
+	} drag;
+
 	struct wl_client *active_client_while_inhibited;
 	struct wl_list inputs;
 	struct wl_listener new_input;
@@ -163,9 +172,6 @@ struct seat {
 	struct wl_listener touch_motion;
 	struct wl_listener touch_frame;
 
-	struct wl_listener request_start_drag;
-	struct wl_listener start_drag;
-	struct wl_listener destroy_drag;
 	struct wl_listener constraint_commit;
 	struct wl_listener idle_inhibitor_create;
 	struct wl_listener pressed_surface_destroy;

src/cursor.c

@@ -9,6 +9,7 @@
 #include "common/mem.h"
 #include "common/scene-helpers.h"
 #include "config/mousebind.h"
+#include "dnd.h"
 #include "labwc.h"
 #include "menu/menu.h"
 #include "resistance.h"
@@ -172,21 +173,6 @@ request_set_primary_selection_notify(struct wl_listener *listener, void *data)
 		event->serial);
 }
 
-static void
-request_start_drag_notify(struct wl_listener *listener, void *data)
-{
-	struct seat *seat = wl_container_of(
-		listener, seat, request_start_drag);
-	struct wlr_seat_request_start_drag_event *event = data;
-	if (wlr_seat_validate_pointer_grab_serial(seat->seat, event->origin,
-			event->serial)) {
-		wlr_seat_start_pointer_drag(seat->seat, event->drag,
-			event->serial);
-	} else {
-		wlr_data_source_destroy(event->drag->source);
-	}
-}
-
 static void
 process_cursor_move(struct server *server, uint32_t time)
 {
@@ -348,7 +334,7 @@ cursor_update_common(struct server *server, struct cursor_context *ctx,
 	/* TODO: verify drag_icon logic */
 	if (seat->pressed.surface && ctx->surface != seat->pressed.surface
 			&& !update_pressed_surface(seat, ctx)
-			&& !seat->drag_icon) {
+			&& !seat->drag.active) {
 		if (cursor_has_moved) {
 			/*
 			 * Button has been pressed while over another
@@ -403,7 +389,7 @@ cursor_update_common(struct server *server, struct cursor_context *ctx,
 		 * a drag operation.
 		 */
 		wlr_seat_pointer_notify_clear_focus(wlr_seat);
-		if (!seat->drag_icon) {
+		if (!seat->drag.active) {
 			cursor_set(seat, cursor_get_from_ssd(ctx->type));
 		}
 	}
@@ -446,6 +432,10 @@ process_cursor_motion(struct server *server, uint32_t time)
 		return;
 	}
 
+	if (seat->drag.active) {
+		dnd_icons_move(seat, seat->cursor->x, seat->cursor->y);
+	}
+
 	if (ctx.view && rc.focus_follow_mouse) {
 		desktop_focus_and_activate_view(seat, ctx.view);
 		if (rc.raise_on_focus) {
@@ -490,21 +480,6 @@ cursor_update_focus(struct server *server)
 		/*cursor_has_moved*/ false);
 }
 
-void
-start_drag(struct wl_listener *listener, void *data)
-{
-	struct seat *seat = wl_container_of(listener, seat, start_drag);
-	struct wlr_drag *wlr_drag = data;
-	seat_reset_pressed(seat);
-	seat->drag_icon = wlr_drag->icon;
-	if (!seat->drag_icon) {
-		wlr_log(WLR_ERROR,
-			"Started drag but application did not set a drag icon");
-		return;
-	}
-	wl_signal_add(&seat->drag_icon->events.destroy, &seat->destroy_drag);
-}
-
 void
 handle_constraint_commit(struct wl_listener *listener, void *data)
 {
@@ -611,18 +586,6 @@ cursor_motion(struct wl_listener *listener, void *data)
 	process_cursor_motion(seat->server, event->time_msec);
 }
 
-void
-destroy_drag(struct wl_listener *listener, void *data)
-{
-	struct seat *seat = wl_container_of(listener, seat, destroy_drag);
-
-	if (!seat->drag_icon) {
-		return;
-	}
-	seat->drag_icon = NULL;
-	desktop_focus_topmost_mapped_view(seat->server);
-}
-
 void
 cursor_motion_absolute(struct wl_listener *listener, void *data)
 {
@@ -1022,6 +985,8 @@ cursor_init(struct seat *seat)
 		cursor_names = cursors_x11;
 	}
 
+	dnd_init(seat);
+
 	seat->cursor_motion.notify = cursor_motion;
 	wl_signal_add(&seat->cursor->events.motion, &seat->cursor_motion);
 	seat->cursor_motion_absolute.notify = cursor_motion_absolute;
@@ -1054,13 +1019,6 @@ cursor_init(struct seat *seat)
 	seat->request_set_selection.notify = request_set_selection_notify;
 	wl_signal_add(&seat->seat->events.request_set_selection,
 		&seat->request_set_selection);
-	seat->request_start_drag.notify = request_start_drag_notify;
-	wl_signal_add(&seat->seat->events.request_start_drag,
-		&seat->request_start_drag);
-	seat->start_drag.notify = start_drag;
-	wl_signal_add(&seat->seat->events.start_drag,
-		&seat->start_drag);
-	seat->destroy_drag.notify = destroy_drag;
 
 	seat->request_set_primary_selection.notify =
 		request_set_primary_selection_notify;
@@ -1070,6 +1028,8 @@ cursor_init(struct seat *seat)
 
 void cursor_finish(struct seat *seat)
 {
+	/* TODO: either clean up all the listeners or none of them */
+
 	wl_list_remove(&seat->cursor_motion.link);
 	wl_list_remove(&seat->cursor_motion_absolute.link);
 	wl_list_remove(&seat->cursor_button.link);
@@ -1088,4 +1048,6 @@ void cursor_finish(struct seat *seat)
 
 	wlr_xcursor_manager_destroy(seat->xcursor_manager);
 	wlr_cursor_destroy(seat->cursor);
+
+	dnd_finish(seat);
 }

src/desktop.c

@@ -3,6 +3,7 @@
 #include <assert.h>
 #include "common/list.h"
 #include "common/scene-helpers.h"
+#include "dnd.h"
 #include "labwc.h"
 #include "layers.h"
 #include "node.h"
@@ -295,10 +296,20 @@ get_cursor_context(struct server *server)
 {
 	struct cursor_context ret = {.type = LAB_SSD_NONE};
 	struct wlr_cursor *cursor = server->seat.cursor;
+
+	/* Prevent drag icons to be on top of the hitbox detection */
+	if (server->seat.drag.active) {
+		dnd_icons_show(&server->seat, false);
+	}
+
 	struct wlr_scene_node *node =
 		wlr_scene_node_at(&server->scene->tree.node,
 			cursor->x, cursor->y, &ret.sx, &ret.sy);
 
+	if (server->seat.drag.active) {
+		dnd_icons_show(&server->seat, true);
+	}
+
 	ret.node = node;
 	if (!node) {
 		ret.type = LAB_SSD_ROOT;

src/dnd.c

@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <assert.h>
+#include <wlr/types/wlr_data_device.h>
+#include <wlr/types/wlr_scene.h>
+#include <wlr/util/log.h>
+#include "common/mem.h"
+#include "dnd.h"
+#include "labwc.h"  /* for struct seat */
+
+/* Internal DnD icon handlers */
+static void
+handle_icon_map(struct wl_listener *listener, void *data)
+{
+	struct drag_icon *self = wl_container_of(listener, self, events.map);
+	struct wlr_drag_icon *icon = data;
+	if (icon->data) {
+		struct wlr_scene_tree *surface_tree = icon->data;
+		wlr_scene_node_set_enabled(&surface_tree->node, true);
+	} else {
+		icon->data = wlr_scene_subsurface_tree_create(
+			self->icon_tree, icon->surface);
+	}
+}
+
+static void
+handle_surface_commit(struct wl_listener *listener, void *data)
+{
+	struct drag_icon *self = wl_container_of(listener, self, events.commit);
+	struct wlr_surface *surface = data;
+	struct wlr_scene_tree *surface_tree = self->icon->data;
+	if (surface_tree) {
+		wlr_scene_node_set_position(&surface_tree->node,
+			surface->sx, surface->sy);
+	}
+}
+
+static void
+handle_icon_unmap(struct wl_listener *listener, void *data)
+{
+	struct drag_icon *self = wl_container_of(listener, self, events.unmap);
+	struct wlr_drag_icon *icon = data;
+	struct wlr_scene_tree *surface_tree = icon->data;
+	if (surface_tree) {
+		wlr_scene_node_set_enabled(&surface_tree->node, false);
+	}
+}
+
+static void
+handle_icon_destroy(struct wl_listener *listener, void *data)
+{
+	struct drag_icon *self = wl_container_of(listener, self, events.destroy);
+
+	wl_list_remove(&self->events.map.link);
+	wl_list_remove(&self->events.commit.link);
+	wl_list_remove(&self->events.unmap.link);
+	wl_list_remove(&self->events.destroy.link);
+
+	if (self->icon->data) {
+		struct wlr_scene_tree *tree = self->icon->data;
+		wlr_scene_node_destroy(&tree->node);
+	}
+
+	self->icon = NULL;
+	self->icon_tree = NULL;
+	free(self);
+}
+
+static void
+drag_icon_create(struct seat *seat, struct wlr_drag_icon *wlr_icon)
+{
+	assert(seat);
+	assert(wlr_icon);
+	struct drag_icon *self = znew(*self);
+
+	self->icon = wlr_icon;
+	self->icon_tree = seat->drag.icons;
+
+	/* Position will be updated by cursor movement */
+	wlr_scene_node_set_position(&self->icon_tree->node,
+		seat->cursor->x, seat->cursor->y);
+	wlr_scene_node_raise_to_top(&self->icon_tree->node);
+
+	/* Set up events */
+	self->events.map.notify = handle_icon_map;
+	self->events.commit.notify = handle_surface_commit;
+	self->events.unmap.notify = handle_icon_unmap;
+	self->events.destroy.notify = handle_icon_destroy;
+
+	wl_signal_add(&wlr_icon->events.map, &self->events.map);
+	wl_signal_add(&wlr_icon->surface->events.commit, &self->events.commit);
+	wl_signal_add(&wlr_icon->events.unmap, &self->events.unmap);
+	wl_signal_add(&wlr_icon->events.destroy, &self->events.destroy);
+}
+
+/* Internal DnD handlers */
+static void
+handle_drag_request(struct wl_listener *listener, void *data)
+{
+	struct seat *seat = wl_container_of(listener, seat, drag.events.request);
+	struct wlr_seat_request_start_drag_event *event = data;
+
+	if (wlr_seat_validate_pointer_grab_serial(
+			seat->seat, event->origin, event->serial)) {
+		wlr_seat_start_pointer_drag(seat->seat, event->drag,
+			event->serial);
+	} else {
+		wlr_data_source_destroy(event->drag->source);
+		wlr_log(WLR_ERROR, "wrong source for drag request");
+	}
+}
+
+static void
+handle_drag_start(struct wl_listener *listener, void *data)
+{
+	struct seat *seat = wl_container_of(listener, seat, drag.events.start);
+	assert(!seat->drag.active);
+	struct wlr_drag *drag = data;
+
+	seat->drag.active = true;
+	seat_reset_pressed(seat);
+	if (drag->icon) {
+		/* Cleans up automatically on drag->icon->events.detroy */
+		drag_icon_create(seat, drag->icon);
+		wlr_scene_node_set_enabled(&seat->drag.icons->node, true);
+	}
+	wl_signal_add(&drag->events.destroy, &seat->drag.events.destroy);
+}
+
+static void
+handle_drag_destroy(struct wl_listener *listener, void *data)
+{
+	struct seat *seat = wl_container_of(listener, seat, drag.events.destroy);
+	assert(seat->drag.active);
+
+	seat->drag.active = false;
+	wl_list_remove(&seat->drag.events.destroy.link);
+	wlr_scene_node_set_enabled(&seat->drag.icons->node, false);
+	/* TODO: Not sure we actually need the following */
+	desktop_focus_topmost_mapped_view(seat->server);
+}
+
+/* Public API */
+void
+dnd_init(struct seat *seat)
+{
+	seat->drag.icons = wlr_scene_tree_create(&seat->server->scene->tree);
+	wlr_scene_node_set_enabled(&seat->drag.icons->node, false);
+
+	seat->drag.events.request.notify = handle_drag_request;
+	seat->drag.events.start.notify = handle_drag_start;
+	seat->drag.events.destroy.notify = handle_drag_destroy;
+
+	wl_signal_add(&seat->seat->events.request_start_drag,
+		&seat->drag.events.request);
+	wl_signal_add(&seat->seat->events.start_drag, &seat->drag.events.start);
+	/*
+	 * destroy.notify is listened to in handle_drag_start() and reset in
+	 * handle_drag_destroy()
+	 */
+}
+
+void
+dnd_icons_show(struct seat *seat, bool show)
+{
+	wlr_scene_node_set_enabled(&seat->drag.icons->node, show);
+}
+
+void
+dnd_icons_move(struct seat *seat, double x, double y)
+{
+	wlr_scene_node_set_position(&seat->drag.icons->node, x, y);
+}
+
+void dnd_finish(struct seat *seat)
+{
+	wlr_scene_node_destroy(&seat->drag.icons->node);
+	wl_list_remove(&seat->drag.events.request.link);
+	wl_list_remove(&seat->drag.events.start.link);
+}

src/meson.build

@@ -4,6 +4,7 @@ labwc_sources = files(
   'cursor.c',
   'debug.c',
   'desktop.c',
+  'dnd.c',
   'foreign.c',
   'interactive.c',
   'keyboard.c',