xdg-shell stable: Make sure popup parent is topmost popup when grabbing

Avoids protocol errors on Weston, gnome-shell and wlroots-based compositors.

This is the same fix as 75c996e7, but for the stable version of xdg shell.

Change-Id: Ic998fb920a8b1b131e42833a61e663704c8663e4
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

2 files changed, 32 insertions, 3 deletions

diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
index 7dabd96f2..8b3d07481 100644
--- a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
@@ -182,6 +182,7 @@ QWaylandXdgSurface::Popup::Popup(QWaylandXdgSurface *xdgSurface, QWaylandXdgSurf
                                  QtWayland::xdg_positioner *positioner)
     : xdg_popup(xdgSurface->get_popup(parent->object(), positioner->object()))
     , m_xdgSurface(xdgSurface)
+    , m_parent(parent)
 {
 }
 
@@ -189,6 +190,19 @@ QWaylandXdgSurface::Popup::~Popup()
 {
     if (isInitialized())
         destroy();
+
+    if (m_grabbing) {
+        auto *shell = m_xdgSurface->m_shell;
+        Q_ASSERT(shell->m_topmostPopup == this);
+        shell->m_topmostPopup = m_parent->m_popup;
+    }
+}
+
+void QWaylandXdgSurface::Popup::grab(QWaylandInputDevice *seat, uint serial)
+{
+    m_xdgSurface->m_shell->m_topmostPopup = this;
+    xdg_popup::grab(seat->wl_seat(), serial);
+    m_grabbing = true;
 }
 
 void QWaylandXdgSurface::Popup::xdg_popup_popup_done()
@@ -317,6 +331,14 @@ void QWaylandXdgSurface::setPopup(QWaylandWindow *parent, QWaylandInputDevice *d
     Q_ASSERT(!m_toplevel && !m_popup);
 
     auto parentXdgSurface = static_cast<QWaylandXdgSurface *>(parent->shellSurface());
+
+    auto *top = m_shell->m_topmostPopup;
+    if (grab && top && top->m_xdgSurface != parentXdgSurface) {
+        qCWarning(lcQpaWayland) << "setPopup called for a surface that was not the topmost popup, positions might be off.";
+        parentXdgSurface = top->m_xdgSurface;
+        parent = top->m_xdgSurface->m_window;
+    }
+
     auto positioner = new QtWayland::xdg_positioner(m_shell->create_positioner());
     // set_popup expects a position relative to the parent
     QPoint transientPos = m_window->geometry().topLeft(); // this is absolute
@@ -332,9 +354,8 @@ void QWaylandXdgSurface::setPopup(QWaylandWindow *parent, QWaylandInputDevice *d
     m_popup = new Popup(this, parentXdgSurface, positioner);
     positioner->destroy();
     delete positioner;
-    if (grab) {
-        m_popup->grab(device->wl_seat(), serial);
-    }
+    if (grab)
+        m_popup->grab(device, serial);
 }
 
 void QWaylandXdgSurface::xdg_surface_configure(uint32_t serial)
diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h
index 37a4a8a4c..45d7d4b0e 100644
--- a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h
@@ -129,9 +129,12 @@ private:
         Popup(QWaylandXdgSurface *xdgSurface, QWaylandXdgSurface *parent, QtWayland::xdg_positioner *positioner);
         ~Popup() override;
 
+        void grab(QWaylandInputDevice *seat, uint serial);
         void xdg_popup_popup_done() override;
 
         QWaylandXdgSurface *m_xdgSurface = nullptr;
+        QWaylandXdgSurface *m_parent = nullptr;
+        bool m_grabbing = false;
     };
 
     void setToplevel();
@@ -144,6 +147,8 @@ private:
     bool m_configured = false;
     QRegion m_exposeRegion;
     uint m_pendingConfigureSerial = 0;
+
+    friend class QWaylandXdgShell;
 };
 
 class Q_WAYLAND_CLIENT_EXPORT QWaylandXdgShell : public QtWayland::xdg_wm_base
@@ -164,6 +169,9 @@ private:
 
     QWaylandDisplay *m_display = nullptr;
     QScopedPointer<QWaylandXdgDecorationManagerV1> m_xdgDecorationManager;
+    QWaylandXdgSurface::Popup *m_topmostPopup = nullptr;
+
+    friend class QWaylandXdgSurface;
 };
 
 QT_END_NAMESPACE