From 98563729320aadfb7a3cecc42e43b147fabb143d Mon Sep 17 00:00:00 2001
From: "Enrico Weigelt, metux IT consult" <info@metux.net>
Date: Thu, 18 Sep 2025 18:31:16 +0200
Subject: [PATCH] dix: add callback before ClientRec is being destroyed

Existing client-state hook isn't sufficient for this, and so easy to
be extended cleanly (*1). Adding a new callback is trivial and cheap,
so preferring this way, instead of trying to tweak the existing hook
for something it's never been designed for.

*1) see discussion here: https://github.com/X11Libre/xserver/pull/1077

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
---
 dix/client.c      | 11 +++++++++++
 dix/client_priv.h | 16 ++++++++++++++++
 dix/dispatch.c    |  2 ++
 dix/meson.build   |  1 +
 os/client_priv.h  |  4 ++--
 5 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 dix/client.c
 create mode 100644 dix/client_priv.h

diff --git a/dix/client.c b/dix/client.c
new file mode 100644
index 000000000..2c32318ea
--- /dev/null
+++ b/dix/client.c
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: MIT OR X11
+ *
+ * Copyright © 2024 Enrico Weigelt, metux IT consult <info@metux.net>
+ */
+#include <dix-config.h>
+
+#include <stddef.h>
+
+#include "include/callback.h"
+
+CallbackListPtr ClientDestroyCallback = NULL;
diff --git a/dix/client_priv.h b/dix/client_priv.h
new file mode 100644
index 000000000..99eb4790f
--- /dev/null
+++ b/dix/client_priv.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: MIT OR X11
+ *
+ * Copyright © 2024 Enrico Weigelt, metux IT consult <info@metux.net>
+ */
+#ifndef _XSERVER_DIX_CLIENT_PRIV_H
+#define _XSERVER_DIX_CLIENT_PRIV_H
+
+#include "include/callback.h"
+
+/*
+ * called right before ClientRec is about to be destroyed,
+ * after resources have been freed. argument is ClientPtr
+ */
+extern CallbackListPtr ClientDestroyCallback;
+
+#endif /* _XSERVER_DIX_CLIENT_PRIV_H */
diff --git a/dix/dispatch.c b/dix/dispatch.c
index 96ef412cc..0a7fc948c 100644
--- a/dix/dispatch.c
+++ b/dix/dispatch.c
@@ -103,6 +103,7 @@ Equipment Corporation.
 #include <X11/fonts/fontstruct.h>
 #include <X11/fonts/libxfont2.h>
 
+#include "dix/client_priv.h"
 #include "dix/colormap_priv.h"
 #include "dix/cursor_priv.h"
 #include "dix/dix_priv.h"
@@ -3550,6 +3551,7 @@ CloseDownClient(ClientPtr client)
         TouchListenerGone(client->clientAsMask);
         GestureListenerGone(client->clientAsMask);
         FreeClientResources(client);
+        CallCallbacks(&ClientDestroyCallback, client);
         /* Disable client ID tracking. This must be done after
          * ClientStateCallback. */
         ReleaseClientIds(client);
diff --git a/dix/meson.build b/dix/meson.build
index 85f633421..0c3c662b9 100644
--- a/dix/meson.build
+++ b/dix/meson.build
@@ -1,5 +1,6 @@
 srcs_dix = [
     'atom.c',
+    'client.c',
     'colormap.c',
     'color.c',
     'cursor.c',
diff --git a/os/client_priv.h b/os/client_priv.h
index 8bb0acf51..d0642f131 100644
--- a/os/client_priv.h
+++ b/os/client_priv.h
@@ -3,8 +3,8 @@
  * Copyright © 2024 Enrico Weigelt, metux IT consult <info@metux.net>
  * Copyright © 2010 Nokia Corporation and/or its subsidiary(-ies).
  */
-#ifndef _XSERVER_DIX_CLIENT_PRIV_H
-#define _XSERVER_DIX_CLIENT_PRIV_H
+#ifndef _XSERVER_OS_CLIENT_PRIV_H
+#define _XSERVER_OS_CLIENT_PRIV_H
 
 #include <sys/types.h>
 #include <X11/Xdefs.h>