Client: Don't attach buffers to unexposed windows

QBackingStore::flush is sometimes called with an unxeposed window, in that
case, don't attach the buffer to the wl_surface immediately, as that causes
protocol errors with xdg_shell.

Flushed buffers are instead stored until we get the first configure event.

[ChangeLog][QPA plugin][xdg-shell] Fixed a bug where buffers were sometimes
attached and committed before the first configure event, causing protocol
errors.

Fixes: QTBUG-71345
Change-Id: If9409d97bd25f6b13940c56141920a664c349c8e
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>
Reviewed-by: David Edmundson <davidedmundson@kde.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/client/qwaylandwindow_p.h b/src/client/qwaylandwindow_p.h
index d11ed871b..ad24b7358 100644
--- a/src/client/qwaylandwindow_p.h
+++ b/src/client/qwaylandwindow_p.h
@@ -116,6 +116,8 @@ public:
     using QtWayland::wl_surface::damage;
     void damage(const QRect &rect);
 
+    void safeCommit(QWaylandBuffer *buffer, const QRegion &damage);
+    void handleExpose(const QRegion &region);
     void commit(QWaylandBuffer *buffer, const QRegion &damage);
 
     void waitForFrameSync();
@@ -231,6 +233,8 @@ protected:
     Qt::WindowStates mLastReportedWindowStates = Qt::WindowNoState;
 
     QWaylandShmBackingStore *mBackingStore = nullptr;
+    QWaylandBuffer *mQueuedBuffer = nullptr;
+    QRegion mQueuedBufferDamage;
 
 private slots:
     void handleScreenRemoved(QScreen *qScreen);