From 7053e4fce665ad139ae88d48a5aab54eb85b6dbe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <mgraesslin@kde.org>
Date: Wed, 30 Mar 2016 10:16:39 +0200
Subject: [PATCH] [server] Don't emit unmapped if the Surface wasn't mapped

Summary:
If a Surface doesn't have a buffer attached and a null buffer gets
attached the buffer state doesn't really change. Thus neither the
unmapped signal nor the damaged signal should not be emitted.

Reviewers: #plasma

Subscribers: plasma-devel

Projects: #plasma

Differential Revision: https://phabricator.kde.org/D1261
---
 .../autotests/client/test_wayland_surface.cpp | 26 +++++++++++++++++++
 src/wayland/surface_interface.cpp             |  6 ++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/wayland/autotests/client/test_wayland_surface.cpp b/src/wayland/autotests/client/test_wayland_surface.cpp
index 1860f45179..a808272cbe 100644
--- a/src/wayland/autotests/client/test_wayland_surface.cpp
+++ b/src/wayland/autotests/client/test_wayland_surface.cpp
@@ -53,6 +53,7 @@ private Q_SLOTS:
     void testInput();
     void testScale();
     void testDestroy();
+    void testUnmapOfNotMappedSurface();
 
 private:
     KWayland::Server::Display *m_display;
@@ -706,5 +707,30 @@ void TestWaylandSurface::testDestroy()
     s->destroy();
 }
 
+void TestWaylandSurface::testUnmapOfNotMappedSurface()
+{
+    // this test verifies that a surface which doesn't have a buffer attached doesn't trigger the unmapped signal
+    using namespace KWayland::Client;
+    using namespace KWayland::Server;
+    // create surface
+    QSignalSpy serverSurfaceCreated(m_compositorInterface, &CompositorInterface::surfaceCreated);
+    QVERIFY(serverSurfaceCreated.isValid());
+    QScopedPointer<Surface> s(m_compositor->createSurface());
+    QVERIFY(serverSurfaceCreated.wait());
+    SurfaceInterface *serverSurface = serverSurfaceCreated.first().first().value<KWayland::Server::SurfaceInterface*>();
+
+    QSignalSpy unmappedSpy(serverSurface, &SurfaceInterface::unmapped);
+    QVERIFY(unmappedSpy.isValid());
+    QSignalSpy scaleChanged(serverSurface, &SurfaceInterface::scaleChanged);
+
+    // let's map a null buffer and change scale to trigger a signal we can wait for
+    s->attachBuffer(Buffer::Ptr());
+    s->setScale(2);
+    s->commit(Surface::CommitFlag::None);
+
+    QVERIFY(scaleChanged.wait());
+    QVERIFY(unmappedSpy.isEmpty());
+}
+
 QTEST_GUILESS_MAIN(TestWaylandSurface)
 #include "test_wayland_surface.moc"
diff --git a/src/wayland/surface_interface.cpp b/src/wayland/surface_interface.cpp
index bc34af6bba..56fc18fe72 100644
--- a/src/wayland/surface_interface.cpp
+++ b/src/wayland/surface_interface.cpp
@@ -238,7 +238,7 @@ void SurfaceInterface::Private::destroy()
 void SurfaceInterface::Private::swapStates(State *source, State *target, bool emitChanged)
 {
     Q_Q(SurfaceInterface);
-    const bool bufferChanged = source->bufferIsSet;
+    bool bufferChanged = source->bufferIsSet;
     const bool opaqueRegionChanged = source->opaqueIsSet;
     const bool inputRegionChanged = source->inputIsSet;
     const bool scaleFactorChanged = source->scaleIsSet && (target->scale != source->scale);
@@ -271,6 +271,10 @@ void SurfaceInterface::Private::swapStates(State *source, State *target, bool em
             const QSize newSize = source->buffer->size();
             sizeChanged = newSize.isValid() && newSize != oldSize;
         }
+        if (!target->buffer && !source->buffer && emitChanged) {
+            // null buffer set on a not mapped surface, don't emit unmapped
+            bufferChanged = false;
+        }
         buffer = source->buffer;
     }
     // copy values