From bf228370ffc156b97be5aec58072142fe79daf9b Mon Sep 17 00:00:00 2001
From: Daniel Stone <daniels@collabora.com>
Date: Tue, 27 Jun 2023 14:04:41 +0100
Subject: [PATCH] view: Add view_list_needs_rebuild member

Most of the time when we're changing things about views, we don't need
to throw away the view list and rebuild it from scratch. The only times
when we need to do this are when views have been added to or removed
from the scene graph, or have been restacked within it.

Signed-off-by: Daniel Stone <daniels@collabora.com>
---
 include/libweston/libweston.h |  2 ++
 libweston/compositor.c        | 19 +++++++++++++++----
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/include/libweston/libweston.h b/include/libweston/libweston.h
index df545eac..de4f56a2 100644
--- a/include/libweston/libweston.h
+++ b/include/libweston/libweston.h
@@ -1417,6 +1417,8 @@ struct weston_compositor {
 	struct wl_list axis_binding_list;
 	struct wl_list debug_binding_list;
 
+	bool view_list_needs_rebuild;
+
 	uint32_t state;
 	struct wl_event_source *idle_source;
 	uint32_t idle_inhibit;
diff --git a/libweston/compositor.c b/libweston/compositor.c
index 57a3317b..9cb3bd1b 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -1578,6 +1578,7 @@ WL_EXPORT void
 weston_view_geometry_dirty(struct weston_view *view)
 {
 	weston_view_geometry_dirty_internal(view);
+	view->surface->compositor->view_list_needs_rebuild = true;
 }
 
 /**
@@ -2146,12 +2147,14 @@ weston_view_unmap(struct weston_view *view)
 		}
 	}
 	weston_signal_emit_mutable(&view->unmap_signal, view);
+	view->surface->compositor->view_list_needs_rebuild = true;
 }
 
 WL_EXPORT void
 weston_surface_map(struct weston_surface *surface)
 {
 	surface->is_mapped = true;
+	surface->compositor->view_list_needs_rebuild = true;
 	weston_signal_emit_mutable(&surface->map_signal, surface);
 }
 
@@ -2171,7 +2174,6 @@ WL_EXPORT void
 weston_view_destroy(struct weston_view *view)
 {
 	struct weston_paint_node *pnode, *pntmp;
-	struct weston_compositor *compositor = view->surface->compositor;
 
 	if (weston_view_is_mapped(view))
 		weston_view_unmap(view);
@@ -2197,8 +2199,6 @@ weston_view_destroy(struct weston_view *view)
 	wl_list_remove(&view->surface_link);
 
 	free(view);
-
-	weston_compositor_build_view_list(compositor);
 }
 
 WL_EXPORT struct weston_surface *
@@ -3115,6 +3115,8 @@ weston_compositor_build_view_list(struct weston_compositor *compositor)
 
 	wl_list_for_each(output, &compositor->output_list, link)
 		weston_output_build_z_order_list(compositor, output);
+
+	compositor->view_list_needs_rebuild = false;
 }
 
 static void
@@ -3161,7 +3163,8 @@ weston_output_repaint(struct weston_output *output)
 	TL_POINT(ec, "core_repaint_begin", TLP_OUTPUT(output), TLP_END);
 
 	/* Rebuild the surface list and update surface transforms up front. */
-	weston_compositor_build_view_list(ec);
+	if (ec->view_list_needs_rebuild)
+		weston_compositor_build_view_list(ec);
 
 	/* Find the highest protection desired for an output */
 	wl_list_for_each(pnode, &output->paint_node_z_order_list,
@@ -3574,6 +3577,8 @@ weston_view_move_to_layer(struct weston_view *view,
 	if (layer == &view->layer_link)
 		return;
 
+	view->surface->compositor->view_list_needs_rebuild = true;
+
 	/* Damage the view's old region, and remove it from the layer. */
 	if (weston_view_is_mapped(view)) {
 		weston_view_damage_below(view);
@@ -3693,6 +3698,8 @@ weston_layer_set_mask(struct weston_layer *layer,
 	wl_list_for_each(view, &layer->view_list.link, layer_link.link) {
 		weston_view_geometry_dirty_internal(view);
 	}
+
+	layer->compositor->view_list_needs_rebuild = true;
 }
 
 WL_EXPORT void
@@ -3708,6 +3715,8 @@ weston_layer_set_mask_infinite(struct weston_layer *layer)
 	wl_list_for_each(view, &layer->view_list.link, layer_link.link) {
 		weston_view_geometry_dirty_internal(view);
 	}
+
+	layer->compositor->view_list_needs_rebuild = true;
 }
 
 WL_EXPORT bool
@@ -4363,6 +4372,8 @@ surface_commit(struct wl_client *client, struct wl_resource *resource)
 		status |= weston_surface_commit(surface);
 	}
 
+	if (status & WESTON_SURFACE_DIRTY_SUBSURFACE_CONFIG)
+		surface->compositor->view_list_needs_rebuild = true;
 }
 
 static void