From 9f7e532852ba199b845f6ac9c98804010fbe378e Mon Sep 17 00:00:00 2001
From: tokyo4j <hrak1529@gmail.com>
Date: Tue, 9 Sep 2025 02:56:37 +0900
Subject: [PATCH] desktop: refactor get_cursor_context()

This patch should not change any behaviors.

This clarifies the semantics of cursor_context returned by
get_cursor_context() as I described in cursor.h; when cursor is on a
subsurface (e.g. xdg/x11/layer/session-lock), the returned ctx.surface
and ctx.node points to the subsurface rather than its parent.
---
 include/input/cursor.h | 32 +++++++++++---------------------
 src/desktop.c          | 10 ++++------
 2 files changed, 15 insertions(+), 27 deletions(-)

diff --git a/include/input/cursor.h b/include/input/cursor.h
index 5afa831b..13ab72d1 100644
--- a/include/input/cursor.h
+++ b/include/input/cursor.h
@@ -39,30 +39,20 @@ struct cursor_context {
 };
 
 /**
- * get_cursor_context - find view and scene_node at cursor
+ * get_cursor_context - find view, surface and scene_node at cursor
  *
- * Behavior if node points to a surface:
- *  - If surface is a layer-surface, type will be
- *    set to LAB_NODE_LAYER_SURFACE and view will be NULL.
+ * If the cursor is on a client-drawn surface:
+ * - ctx.{surface,node} points to the surface, which may be a subsurface.
+ * - ctx.view is set if the node is associated to a xdg/x11 window.
+ * - ctx.type is LAYER_SURFACE or UNMANAGED if the node is a layer-shell
+ *   surface or an X11 unmanaged surface. Otherwise, CLIENT is set.
  *
- *  - If surface is a 'lost' unmanaged xsurface (one
- *    with a never-mapped parent view), type will
- *    be set to LAB_NODE_UNMANAGED and view will be NULL.
- *
- *    'Lost' unmanaged xsurfaces are usually caused by
- *    X11 applications opening popups without setting
- *    the main window as parent. Example: VLC submenus.
- *
- *  - Any other surface will cause type to be set to
- *    LAB_NODE_CLIENT and return the attached view.
- *
- * Behavior if node points to internal elements:
- *  - type will be set to the appropriate enum value
- *    and view will be NULL if the node is not part of the SSD.
- *
- * If no node is found for the given layout coordinates,
- * type will be set to LAB_NODE_ROOT and view will be NULL.
+ * If the cursor is on a server-side component (SSD part and menu item):
+ * - ctx.node points to the root node of that component
+ * - ctx.view is set if the component is a SSD part
+ * - ctx.type specifies the component (e.g. MENU_ITEM, BORDER_TOP, BUTTON_ICONIFY)
  *
+ * If no node is found at cursor, ctx.type is set to ROOT.
  */
 struct cursor_context get_cursor_context(struct server *server);
 
diff --git a/src/desktop.c b/src/desktop.c
index 3ed19082..dc2aa1a2 100644
--- a/src/desktop.c
+++ b/src/desktop.c
@@ -262,18 +262,18 @@ get_cursor_context(struct server *server)
 		dnd_icons_show(&server->seat, true);
 	}
 
-	ret.node = node;
 	if (!node) {
 		ret.type = LAB_NODE_ROOT;
 		return ret;
 	}
+	ret.node = node;
+	ret.surface = lab_wlr_surface_from_node(node);
 
 #if HAVE_XWAYLAND
+	/* TODO: attach LAB_NODE_UNMANAGED node-descriptor to unmanaged surfaces */
 	if (node->type == WLR_SCENE_NODE_BUFFER) {
-		struct wlr_surface *surface = lab_wlr_surface_from_node(node);
 		if (node->parent == server->unmanaged_tree) {
 			ret.type = LAB_NODE_UNMANAGED;
-			ret.surface = surface;
 			return ret;
 		}
 	}
@@ -285,7 +285,6 @@ get_cursor_context(struct server *server)
 			case LAB_NODE_VIEW:
 			case LAB_NODE_XDG_POPUP:
 				ret.view = desc->view;
-				ret.surface = lab_wlr_surface_from_node(ret.node);
 				if (ret.surface) {
 					ret.type = LAB_NODE_CLIENT;
 				} else {
@@ -295,13 +294,11 @@ get_cursor_context(struct server *server)
 				return ret;
 			case LAB_NODE_LAYER_SURFACE:
 				ret.type = LAB_NODE_LAYER_SURFACE;
-				ret.surface = lab_wlr_surface_from_node(ret.node);
 				return ret;
 			case LAB_NODE_LAYER_POPUP:
 			case LAB_NODE_SESSION_LOCK_SURFACE:
 			case LAB_NODE_IME_POPUP:
 				ret.type = LAB_NODE_CLIENT;
-				ret.surface = lab_wlr_surface_from_node(ret.node);
 				return ret;
 			case LAB_NODE_MENUITEM:
 				/* Always return the top scene node for menu items */
@@ -312,6 +309,7 @@ get_cursor_context(struct server *server)
 			case LAB_NODE_SSD_ROOT:
 			case LAB_NODE_TITLE:
 			case LAB_NODE_TITLEBAR:
+				/* Always return the top scene node for ssd parts */
 				ret.node = node;
 				ret.view = desc->view;
 				/*