From fb0a5265ec9d83b56563769cc1b756aeca42ce65 Mon Sep 17 00:00:00 2001
From: Georges Basile Stavracas Neto <gbsneto@gnome.org>
Date: Thu, 27 May 2021 20:02:53 -0300
Subject: [PATCH 20/40] Client: Always destroy frame callback in the actual
 callback

It's good hygiene to destroy all frame callbacks. Destroy the
frame callback and cleanup the mFrameCallback class member in
the callback itself. The callback destruction happens before
calling handleFrameCallback() to avoid the theoretical case
where another frame callback is queued by handleFrameCallback(),
and then immediately destroyed in the callback handler.

* asturmlechner 2021-09-27:
  Conflict resolved from non-backported commit in dev branch:
  93058de8d7e7c2f320c22b3bd898aa06cf5babcd

Change-Id: Ide6dc95e3402932c58bfc088a9d471fda821e9a1
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
(cherry picked from commit 42cdc61a93cf2acb09936aebb5e431fdbc0a26c6)
---
 src/client/qwaylandwindow.cpp | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/client/qwaylandwindow.cpp b/src/client/qwaylandwindow.cpp
index 85307875..c020a58f 100644
--- a/src/client/qwaylandwindow.cpp
+++ b/src/client/qwaylandwindow.cpp
@@ -622,9 +622,13 @@ void QWaylandWindow::commit()
 
 const wl_callback_listener QWaylandWindow::callbackListener = {
     [](void *data, wl_callback *callback, uint32_t time) {
-        Q_UNUSED(callback);
         Q_UNUSED(time);
         auto *window = static_cast<QWaylandWindow*>(data);
+
+        Q_ASSERT(callback == window->mFrameCallback);
+        wl_callback_destroy(callback);
+        window->mFrameCallback = nullptr;
+
         window->handleFrameCallback();
     }
 };
@@ -1179,11 +1183,6 @@ void QWaylandWindow::handleUpdate()
     if (!mSurface)
         return;
 
-    if (mFrameCallback) {
-        wl_callback_destroy(mFrameCallback);
-        mFrameCallback = nullptr;
-    }
-
     QMutexLocker locker(mFrameQueue.mutex);
     struct ::wl_surface *wrappedSurface = reinterpret_cast<struct ::wl_surface *>(wl_proxy_create_wrapper(mSurface->object()));
     wl_proxy_set_queue(reinterpret_cast<wl_proxy *>(wrappedSurface), mFrameQueue.queue);
-- 
2.35.1