cursor: generalize seat->pressed

This commit moduralize seat_{set,reset}_pressed() into
cursor_context_save() so that we can also have seat->hovered later.

include/input/cursor.h

@@ -38,6 +38,14 @@ struct cursor_context {
 	double sx, sy;
 };
 
+/* Used to persistently store cursor context (e.g. in seat->pressed) */
+struct cursor_context_saved {
+	struct cursor_context ctx;
+	struct wl_listener view_destroy;
+	struct wl_listener node_destroy;
+	struct wl_listener surface_destroy;
+};
+
 /**
  * get_cursor_context - find view, surface and scene_node at cursor
  *
@@ -65,6 +73,13 @@ void cursor_set(struct seat *seat, enum lab_cursors cursor);
 
 void cursor_set_visible(struct seat *seat, bool visible);
 
+/*
+ * Safely store a cursor context to saved_ctx. saved_ctx is cleared when either
+ * of its node, surface and view is destroyed.
+ */
+void cursor_context_save(struct cursor_context_saved *saved_ctx,
+	const struct cursor_context *ctx);
+
 /**
  * cursor_get_resize_edges - calculate resize edge based on cursor position
  * @cursor - the current cursor (usually server->seat.cursor)

include/labwc.h

@@ -65,8 +65,7 @@ struct seat {
 	struct input_method_relay *input_method_relay;
 
 	/**
-	 * This is usually zeroed and is only set on button press while the
+	 * Cursor context saved when a mouse button is pressed on a view/surface.
-	 * mouse is over a view or surface, and zeroed on button release.
 	 * It is used to send cursor motion events to a surface even though
 	 * the cursor has left the surface in the meantime.
 	 *
@@ -76,10 +75,8 @@ struct seat {
 	 * It is also used to:
 	 * - determine the target view for action in "Drag" mousebind
 	 * - validate view move/resize requests from CSD clients
-	 *
-	 * Both (view && !surface) and (surface && !view) are possible.
 	 */
-	struct cursor_context pressed;
+	struct cursor_context_saved pressed;
 
 	struct lab_set bound_buttons;
 
@@ -139,7 +136,6 @@ struct seat {
 	struct wl_list tablet_pads;
 
 	struct wl_listener constraint_commit;
-	struct wl_listener pressed_surface_destroy;
 
 	struct wlr_virtual_pointer_manager_v1 *virtual_pointer;
 	struct wl_listener new_virtual_pointer;
@@ -392,8 +388,6 @@ void seat_pointer_end_grab(struct seat *seat, struct wlr_surface *surface);
 void seat_focus_lock_surface(struct seat *seat, struct wlr_surface *surface);
 
 void seat_set_focus_layer(struct seat *seat, struct wlr_layer_surface_v1 *layer);
-void seat_set_pressed(struct seat *seat, struct cursor_context *ctx);
-void seat_reset_pressed(struct seat *seat);
 void seat_output_layout_changed(struct seat *seat);
 
 /*

src/dnd.c

@@ -34,7 +34,7 @@ handle_drag_start(struct wl_listener *listener, void *data)
 	struct wlr_drag *drag = data;
 
 	seat->drag.active = true;
-	seat_reset_pressed(seat);
+	cursor_context_save(&seat->pressed, NULL);
 	if (drag->icon) {
 		/* Cleans up automatically on drag->icon->events.destroy */
 		wlr_scene_drag_icon_create(seat->drag.icons, drag->icon);

src/input/cursor.c

@@ -437,8 +437,72 @@ cursor_update_image(struct seat *seat)
 		cursor_names[cursor]);
 }
 
+static void
+clear_cursor_context(struct cursor_context_saved *saved_ctx)
+{
+	if (saved_ctx->node_destroy.notify) {
+		wl_list_remove(&saved_ctx->node_destroy.link);
+	}
+	if (saved_ctx->surface_destroy.notify) {
+		wl_list_remove(&saved_ctx->surface_destroy.link);
+	}
+	if (saved_ctx->view_destroy.notify) {
+		wl_list_remove(&saved_ctx->view_destroy.link);
+	}
+	*saved_ctx = (struct cursor_context_saved) {0};
+}
+
+static void
+handle_ctx_node_destroy(struct wl_listener *listener, void *data)
+{
+	struct cursor_context_saved *saved_ctx =
+		wl_container_of(listener, saved_ctx, node_destroy);
+	clear_cursor_context(saved_ctx);
+}
+
+static void
+handle_ctx_surface_destroy(struct wl_listener *listener, void *data)
+{
+	struct cursor_context_saved *saved_ctx =
+		wl_container_of(listener, saved_ctx, surface_destroy);
+	clear_cursor_context(saved_ctx);
+}
+
+static void
+handle_ctx_view_destroy(struct wl_listener *listener, void *data)
+{
+	struct cursor_context_saved *saved_ctx =
+		wl_container_of(listener, saved_ctx, view_destroy);
+	clear_cursor_context(saved_ctx);
+}
+
+void
+cursor_context_save(struct cursor_context_saved *saved_ctx,
+		const struct cursor_context *ctx)
+{
+	assert(saved_ctx);
+
+	clear_cursor_context(saved_ctx);
+	if (!ctx) {
+		return;
+	}
+	saved_ctx->ctx = *ctx;
+	if (ctx->node) {
+		saved_ctx->node_destroy.notify = handle_ctx_node_destroy;
+		wl_signal_add(&ctx->node->events.destroy, &saved_ctx->node_destroy);
+	}
+	if (ctx->surface) {
+		saved_ctx->surface_destroy.notify = handle_ctx_surface_destroy;
+		wl_signal_add(&ctx->surface->events.destroy, &saved_ctx->surface_destroy);
+	}
+	if (ctx->view) {
+		saved_ctx->view_destroy.notify = handle_ctx_view_destroy;
+		wl_signal_add(&ctx->view->events.destroy, &saved_ctx->view_destroy);
+	}
+}
+
 static bool
-update_pressed_surface(struct seat *seat, struct cursor_context *ctx)
+update_pressed_surface(struct seat *seat, const struct cursor_context *ctx)
 {
 	/*
 	 * In most cases, we don't want to leave one surface and enter
@@ -454,10 +518,10 @@ update_pressed_surface(struct seat *seat, struct cursor_context *ctx)
 	if (!wlr_seat_pointer_has_grab(seat->seat)) {
 		return false;
 	}
-	if (seat->pressed.surface && ctx->surface != seat->pressed.surface) {
+	if (seat->pressed.ctx.surface && ctx->surface != seat->pressed.ctx.surface) {
 		struct wlr_surface *toplevel = get_toplevel(ctx->surface);
-		if (toplevel && toplevel == get_toplevel(seat->pressed.surface)) {
+		if (toplevel && toplevel == get_toplevel(seat->pressed.ctx.surface)) {
-			seat_set_pressed(seat, ctx);
+			cursor_context_save(&seat->pressed, ctx);
 			return true;
 		}
 	}
@@ -487,7 +551,7 @@ cursor_update_common(struct server *server, struct cursor_context *ctx,
 	}
 
 	/* TODO: verify drag_icon logic */
-	if (seat->pressed.surface && ctx->surface != seat->pressed.surface
+	if (seat->pressed.ctx.surface && ctx->surface != seat->pressed.ctx.surface
 			&& !update_pressed_surface(seat, ctx)
 			&& !seat->drag.active) {
 		if (cursor_has_moved) {
@@ -499,7 +563,7 @@ cursor_update_common(struct server *server, struct cursor_context *ctx,
 			 * if the cursor moves outside of the surface.
 			 */
 			int lx, ly;
-			wlr_scene_node_coords(seat->pressed.node, &lx, &ly);
+			wlr_scene_node_coords(seat->pressed.ctx.node, &lx, &ly);
 			*sx = server->seat.cursor->x - lx;
 			*sy = server->seat.cursor->y - ly;
 			return true;
@@ -597,8 +661,8 @@ cursor_process_motion(struct server *server, uint32_t time, double *sx, double *
 			 * moving/resizing the wrong view
 			 */
 			mousebind->pressed_in_context = false;
-			actions_run(seat->pressed.view, server,
+			actions_run(seat->pressed.ctx.view, server,
-				&mousebind->actions, &seat->pressed);
+				&mousebind->actions, &seat->pressed.ctx);
 		}
 	}
 
@@ -1073,7 +1137,7 @@ cursor_process_button_press(struct seat *seat, uint32_t button, uint32_t time_ms
 
 	if (ctx.view || ctx.surface) {
 		/* Store cursor context for later action processing */
-		seat_set_pressed(seat, &ctx);
+		cursor_context_save(&seat->pressed, &ctx);
 	}
 
 	if (server->input_mode == LAB_INPUT_STATE_MENU) {
@@ -1138,12 +1202,12 @@ cursor_process_button_release(struct seat *seat, uint32_t button,
 {
 	struct server *server = seat->server;
 	struct cursor_context ctx = get_cursor_context(server);
-	struct wlr_surface *pressed_surface = seat->pressed.surface;
+	struct wlr_surface *pressed_surface = seat->pressed.ctx.surface;
 
 	/* Always notify button release event when it's not bound */
 	const bool notify = !lab_set_contains(&seat->bound_buttons, button);
 
-	seat_reset_pressed(seat);
+	cursor_context_save(&seat->pressed, NULL);
 
 	if (server->input_mode == LAB_INPUT_STATE_MENU) {
 		/* TODO: take into account overflow of time_msec */

src/seat.c

@@ -848,46 +848,6 @@ seat_set_focus_layer(struct seat *seat, struct wlr_layer_surface_v1 *layer)
 	seat->focused_layer = layer;
 }
 
-static void
-pressed_surface_destroy(struct wl_listener *listener, void *data)
-{
-	struct seat *seat = wl_container_of(listener, seat,
-		pressed_surface_destroy);
-
-	/*
-	 * Using data directly prevents 'unused variable'
-	 * warning when compiling without asserts
-	 */
-	assert(data == seat->pressed.surface);
-
-	seat_reset_pressed(seat);
-}
-
-void
-seat_set_pressed(struct seat *seat, struct cursor_context *ctx)
-{
-	assert(ctx);
-	assert(ctx->view || ctx->surface);
-	seat_reset_pressed(seat);
-
-	seat->pressed = *ctx;
-
-	if (ctx->surface) {
-		seat->pressed_surface_destroy.notify = pressed_surface_destroy;
-		wl_signal_add(&ctx->surface->events.destroy,
-			&seat->pressed_surface_destroy);
-	}
-}
-
-void
-seat_reset_pressed(struct seat *seat)
-{
-	if (seat->pressed.surface) {
-		wl_list_remove(&seat->pressed_surface_destroy.link);
-	}
-	seat->pressed = (struct cursor_context){0};
-}
-
 void
 seat_output_layout_changed(struct seat *seat)
 {

src/view.c

@@ -2612,10 +2612,6 @@ view_destroy(struct view *view)
 		server->session_lock_manager->last_active_view = NULL;
 	}
 
-	if (server->seat.pressed.view == view) {
-		seat_reset_pressed(&server->seat);
-	}
-
 	if (view->tiled_region_evacuate) {
 		zfree(view->tiled_region_evacuate);
 	}

src/xdg.c

@@ -400,7 +400,7 @@ handle_request_move(struct wl_listener *listener, void *data)
 	 * want.
 	 */
 	struct view *view = wl_container_of(listener, view, request_move);
-	if (view == view->server->seat.pressed.view) {
+	if (view == view->server->seat.pressed.ctx.view) {
 		interactive_begin(view, LAB_INPUT_STATE_MOVE, LAB_EDGE_NONE);
 	}
 }
@@ -418,7 +418,7 @@ handle_request_resize(struct wl_listener *listener, void *data)
 	 */
 	struct wlr_xdg_toplevel_resize_event *event = data;
 	struct view *view = wl_container_of(listener, view, request_resize);
-	if (view == view->server->seat.pressed.view) {
+	if (view == view->server->seat.pressed.ctx.view) {
 		interactive_begin(view, LAB_INPUT_STATE_RESIZE, event->edges);
 	}
 }

src/xwayland.c

@@ -289,7 +289,7 @@ handle_request_move(struct wl_listener *listener, void *data)
 	 * want.
 	 */
 	struct view *view = wl_container_of(listener, view, request_move);
-	if (view == view->server->seat.pressed.view) {
+	if (view == view->server->seat.pressed.ctx.view) {
 		interactive_begin(view, LAB_INPUT_STATE_MOVE, LAB_EDGE_NONE);
 	}
 }
@@ -307,7 +307,7 @@ handle_request_resize(struct wl_listener *listener, void *data)
 	 */
 	struct wlr_xwayland_resize_event *event = data;
 	struct view *view = wl_container_of(listener, view, request_resize);
-	if (view == view->server->seat.pressed.view) {
+	if (view == view->server->seat.pressed.ctx.view) {
 		interactive_begin(view, LAB_INPUT_STATE_RESIZE, event->edges);
 	}
 }