Add a mechanism to delay unmapping of surfaces

When a client attachs a NULL buffer on a surface we may want to hang on
to the old buffer for a bit, e.g. to do a hide animation.
Add the QWaylandUnmapLock class to keep a surface mapped after an attach(0)
request.

Change-Id: I5d5be0b36410a76a58d2b68c1b2ac5e3b875a801
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/compositor/compositor_api/qwaylandsurface.h b/src/compositor/compositor_api/qwaylandsurface.h
index 653d74c1b..db1e1fb44 100644
--- a/src/compositor/compositor_api/qwaylandsurface.h
+++ b/src/compositor/compositor_api/qwaylandsurface.h
@@ -77,6 +77,7 @@ public:
 
 protected:
     virtual void attach(const QWaylandBufferRef &ref) = 0;
+    virtual void unmap() = 0;
 
     friend class QtWayland::Surface;
 };
@@ -261,6 +262,17 @@ Q_SIGNALS:
     friend class QtWayland::Surface;
 };
 
+class QWaylandUnmapLockPrivate;
+class Q_COMPOSITOR_EXPORT QWaylandUnmapLock
+{
+public:
+    QWaylandUnmapLock(QWaylandSurface *surface);
+    ~QWaylandUnmapLock();
+
+private:
+    QWaylandUnmapLockPrivate *const d;
+};
+
 QT_END_NAMESPACE
 
 #endif // QWAYLANDSURFACE_H