From dd13a976afe195e444f2c170d3be28d5107ce156 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Mon, 2 Sep 2024 14:59:06 +0200
Subject: [PATCH] wm: alloc real view IDs locally

Don't use client-provided view IDs as IDs for the wrapped nitpicker
views. There is no 1:1 relation of IDs and physical views. So if a wm
client re-uses an ID, the physical view is expected to stay in tact.
If the corresponding view object within the wm is not destroyed, however,
its ID remains allocated, which may then conflict the ID of a new view
if the ID is reused by the client. This scenario resulted in the
following error:

  Error: Uncaught exception of type 'Genode::Id_space<Gui::View_ref>::Conflicting_id'

This patch handles the situation by keeping the allocator of physical
views (_real_view) decoupled from the client's ID allocator.

Issue #5242
---
 repos/gems/src/server/wm/gui.h | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/repos/gems/src/server/wm/gui.h b/repos/gems/src/server/wm/gui.h
index 3379749ae4..cd7f101b36 100644
--- a/repos/gems/src/server/wm/gui.h
+++ b/repos/gems/src/server/wm/gui.h
@@ -141,12 +141,11 @@ class Wm::Gui::View : private Genode::Weak_object<View>,
 		};
 
 		View(Real_gui            &real_gui,
-		     View_id       const &real_view_id,
 		     Session_label const &session_label,
 		     bool                 has_alpha)
 		:
 			_session_label(session_label), _real_gui(real_gui),
-			_real_view(_real_view_ref, _real_gui.view_ids, real_view_id),
+			_real_view(_real_view_ref, _real_gui.view_ids),
 			_has_alpha(has_alpha)
 		{ }
 
@@ -273,12 +272,11 @@ class Wm::Gui::Top_level_view : public View, private List<Top_level_view>::Eleme
 	public:
 
 		Top_level_view(Real_gui                     &real_gui,
-		               View_id                       view_id,
 		               bool                          has_alpha,
 		               Window_registry              &window_registry,
 		               Input_origin_changed_handler &input_origin_changed_handler)
 		:
-			View(real_gui, view_id, real_gui.label, has_alpha),
+			View(real_gui, real_gui.label, has_alpha),
 			_window_registry(window_registry),
 			_input_origin_changed_handler(input_origin_changed_handler),
 			_session_label(real_gui.label)
@@ -384,11 +382,10 @@ class Wm::Gui::Child_view : public View, private List<Child_view>::Element
 	public:
 
 		Child_view(Real_gui      &real_gui,
-		           View_id        real_gui_id,
 		           bool           has_alpha,
 		           Weak_ptr<View> parent)
 		:
-			View(real_gui, real_gui_id, real_gui.label, has_alpha), _parent(parent)
+			View(real_gui, real_gui.label, has_alpha), _parent(parent)
 		{
 			try_to_init_real_view();
 		}
@@ -990,7 +987,7 @@ class Wm::Gui::Session_component : public Rpc_object<Gui::Session>,
 				_create_view_with_id<Top_level_view>(_top_level_view_alloc, id, attr,
 					[&] () -> Top_level_view & {
 						view_ptr = new (_top_level_view_alloc)
-							Top_level_view(_real_gui, id, _has_alpha,
+							Top_level_view(_real_gui, _has_alpha,
 							               _window_registry, *this);
 						return *view_ptr;
 					});
@@ -1013,7 +1010,7 @@ class Wm::Gui::Session_component : public Rpc_object<Gui::Session>,
 						_create_view_with_id<Child_view>(_child_view_alloc, id, attr,
 							[&] () -> Child_view & {
 								view_ptr = new (_child_view_alloc)
-									Child_view(_real_gui, id, _has_alpha, parent.weak_ptr());
+									Child_view(_real_gui, _has_alpha, parent.weak_ptr());
 								return *view_ptr;
 							});