[wayland] Make sure fullscreen windows aren't repositioned

Summary:
on X11, setFullScreen is always called after Placement::place()
so they always have the correct geometry.
on wayland, the window if is shown directly as fullscren,
is set fullscreen in init() then place() is evecuted, potentially
moving it to a wrong position and potentially even size (which happens
with maximiziong placement strategy)
so instead of place() the client needs to be explicitly set at
fullscreen geometry

Test Plan:
fullscreen windows always appear with the proper geometry
autotests still pass

Reviewers: #kwin, #plasma, davidedmundson

Reviewed By: #kwin, #plasma, davidedmundson

Subscribers: zzag, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D24542

autotests/integration/placement_test.cpp

@@ -58,6 +58,7 @@ private Q_SLOTS:
     void testPlaceSmart();
     void testPlaceZeroCornered();
     void testPlaceMaximized();
+    void testPlaceMaximizedLeavesFullscreen();
     void testPlaceCentered();
     void testPlaceUnderMouse();
     void testPlaceCascaded();
@@ -204,6 +205,41 @@ void TestPlacement::testPlaceMaximized()
     }
 }
 
+void TestPlacement::testPlaceMaximizedLeavesFullscreen()
+{
+    setPlacementPolicy(Placement::Maximizing);
+
+    // add a top panel
+    QScopedPointer<Surface> panelSurface(Test::createSurface());
+    QScopedPointer<QObject> panelShellSurface(Test::createXdgShellStableSurface(panelSurface.data()));
+    QScopedPointer<PlasmaShellSurface> plasmaSurface(Test::waylandPlasmaShell()->createSurface(panelSurface.data()));
+    plasmaSurface->setRole(PlasmaShellSurface::Role::Panel);
+    plasmaSurface->setPosition(QPoint(0, 0));
+    Test::renderAndWaitForShown(panelSurface.data(), QSize(1280, 20), Qt::blue);
+
+    QScopedPointer<QObject> testParent(new QObject);
+
+    // all windows should be initially fullscreen with an initial configure size sent, despite the policy
+    for (int i = 0; i < 4; i++) {
+        auto surface = Test::createSurface(testParent.data());
+        auto shellSurface = Test::createXdgShellStableSurface(surface, surface, Test::CreationSetup::CreateOnly);
+        shellSurface->setFullscreen(true);
+        QSignalSpy configSpy(shellSurface, &XdgShellSurface::configureRequested);
+        surface->commit(Surface::CommitFlag::None);
+        configSpy.wait();
+
+        auto initiallyConfiguredSize = configSpy[0][0].toSize();
+        auto initiallyConfiguredStates = configSpy[0][1].value<KWayland::Client::XdgShellSurface::States>();
+        shellSurface->ackConfigure(configSpy[0][2].toUInt());
+
+        auto c = Test::renderAndWaitForShown(surface, initiallyConfiguredSize, Qt::red);
+
+        QVERIFY(initiallyConfiguredStates & XdgShellSurface::State::Fullscreen);
+        QCOMPARE(initiallyConfiguredSize, QSize(1280, 1024 ));
+        QCOMPARE(c->frameGeometry(), QRect(0, 0, 1280, 1024));
+    }
+}
+
 void TestPlacement::testPlaceCentered()
 {
     // This test verifies that Centered placement policy works.

autotests/integration/xdgshellclient_test.cpp

@@ -112,6 +112,7 @@ private Q_SLOTS:
     void testXdgNeverCommitted();
     void testXdgInitialState();
     void testXdgInitiallyMaximised();
+    void testXdgInitiallyFullscreen();
     void testXdgInitiallyMinimized();
     void testXdgWindowGeometry();
 };
@@ -1243,6 +1244,32 @@ void TestXdgShellClient::testXdgInitiallyMaximised()
     QCOMPARE(c->size(), QSize(1280, 1024));
 }
 
+void TestXdgShellClient::testXdgInitiallyFullscreen()
+{
+    QScopedPointer<Surface> surface(Test::createSurface());
+    QScopedPointer<XdgShellSurface> shellSurface(Test::createXdgShellStableSurface(surface.data(), nullptr, Test::CreationSetup::CreateOnly));
+    QSignalSpy configureRequestedSpy(shellSurface.data(), &XdgShellSurface::configureRequested);
+
+    shellSurface->setFullscreen(true);
+    surface->commit(Surface::CommitFlag::None);
+
+    configureRequestedSpy.wait();
+
+    QCOMPARE(configureRequestedSpy.count(), 1);
+
+    const auto size = configureRequestedSpy.first()[0].value<QSize>();
+    const auto state = configureRequestedSpy.first()[1].value<KWayland::Client::XdgShellSurface::States>();
+
+    QCOMPARE(size, QSize(1280, 1024));
+    QVERIFY(state & KWayland::Client::XdgShellSurface::State::Fullscreen);
+
+    shellSurface->ackConfigure(configureRequestedSpy.first()[2].toUInt());
+
+    auto c = Test::renderAndWaitForShown(surface.data(), size, Qt::blue);
+    QCOMPARE(c->isFullScreen(), true);
+    QCOMPARE(c->size(), QSize(1280, 1024));
+}
+
 void TestXdgShellClient::testXdgInitiallyMinimized()
 {
     QScopedPointer<Surface> surface(Test::createSurface());

xdgshellclient.cpp

@@ -222,6 +222,10 @@ void XdgShellClient::finishInit()
         updateWindowRules(Rules::All);
     }
 
+    if (isFullScreen()) {
+        needsPlacement = false;
+    }
+
     if (needsPlacement) {
         const QRect area = workspace()->clientArea(PlacementArea, Screens::self()->current(), desktop());
         placeIn(area);