Client: Implement xdg-decoration-unstable-v1 for SSD support

[ChangeLog][QPA plugin] Added client-side support for the
xdg-decoration-unstable-v1 Wayland extension. Qt clients will now let the
compositor draw the window decorations if configured through this extension.

Note: The env var QT_WAYLAND_DISABLE_WINDOWDECORATION is still supported, but
works on a higher level, and for all shell integrations, while xdg-decoration
only works with xdg-shell stable.

Task-number: QTBUG-69746
Change-Id: I9dd0331bbd8d624c6be54ed23ee3b96446d5820d
Reviewed-by: Pier Luigi Fiorini <pierluigi.fiorini@liri.io>

6 files changed, 273 insertions, 8 deletions

diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgdecorationv1.cpp b/src/plugins/shellintegration/xdg-shell/qwaylandxdgdecorationv1.cpp
new file mode 100644
index 000000000..345ff32ad
--- /dev/null
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgdecorationv1.cpp
@@ -0,0 +1,105 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the config.tests of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qwaylandxdgdecorationv1_p.h"
+#include "qwaylandxdgshell_p.h"
+
+QT_BEGIN_NAMESPACE
+
+namespace QtWaylandClient {
+
+QWaylandXdgDecorationManagerV1::QWaylandXdgDecorationManagerV1(wl_registry *registry, uint32_t id, uint32_t availableVersion)
+    : QtWayland::zxdg_decoration_manager_v1(registry, id, qMin(availableVersion, 1u))
+{
+}
+
+QWaylandXdgDecorationManagerV1::~QWaylandXdgDecorationManagerV1()
+{
+    Q_ASSERT(isInitialized());
+    destroy();
+}
+
+QWaylandXdgToplevelDecorationV1 *QWaylandXdgDecorationManagerV1::createToplevelDecoration(::xdg_toplevel *toplevel)
+{
+    Q_ASSERT(toplevel);
+    return new QWaylandXdgToplevelDecorationV1(get_toplevel_decoration(toplevel));
+}
+
+QWaylandXdgToplevelDecorationV1::QWaylandXdgToplevelDecorationV1(::zxdg_toplevel_decoration_v1 *decoration)
+    : QtWayland::zxdg_toplevel_decoration_v1(decoration)
+{
+}
+
+QWaylandXdgToplevelDecorationV1::~QWaylandXdgToplevelDecorationV1()
+{
+    Q_ASSERT(isInitialized());
+    destroy();
+}
+
+void QWaylandXdgToplevelDecorationV1::requestMode(QtWayland::zxdg_toplevel_decoration_v1::mode mode)
+{
+    // According to the spec the client is responsible for not requesting a mode repeatedly.
+    if (m_modeSet && m_requested == mode)
+        return;
+
+    set_mode(mode);
+    m_requested = mode;
+    m_modeSet = true;
+}
+
+void QWaylandXdgToplevelDecorationV1::unsetMode()
+{
+    unset_mode();
+    m_modeSet = false;
+    m_requested = mode_client_side;
+}
+
+QWaylandXdgToplevelDecorationV1::mode QWaylandXdgToplevelDecorationV1::pending() const
+{
+    return m_pending;
+}
+
+void QtWaylandClient::QWaylandXdgToplevelDecorationV1::zxdg_toplevel_decoration_v1_configure(uint32_t mode)
+{
+    m_pending = zxdg_toplevel_decoration_v1::mode(mode);
+}
+
+}
+
+QT_END_NAMESPACE
diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgdecorationv1_p.h b/src/plugins/shellintegration/xdg-shell/qwaylandxdgdecorationv1_p.h
new file mode 100644
index 000000000..d6d8ce94e
--- /dev/null
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgdecorationv1_p.h
@@ -0,0 +1,97 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the config.tests of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QWAYLANDXDGDECORATIONV1_P_H
+#define QWAYLANDXDGDECORATIONV1_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include "qwayland-xdg-decoration-unstable-v1.h"
+
+#include <QtWaylandClient/qtwaylandclientglobal.h>
+
+QT_BEGIN_NAMESPACE
+
+class QWindow;
+
+namespace QtWaylandClient {
+
+class QWaylandXdgToplevel;
+class QWaylandXdgToplevelDecorationV1;
+
+class Q_WAYLAND_CLIENT_EXPORT QWaylandXdgDecorationManagerV1 : public QtWayland::zxdg_decoration_manager_v1
+{
+public:
+    QWaylandXdgDecorationManagerV1(struct ::wl_registry *registry, uint32_t id, uint32_t availableVersion);
+    ~QWaylandXdgDecorationManagerV1() override;
+    QWaylandXdgToplevelDecorationV1 *createToplevelDecoration(::xdg_toplevel *toplevel);
+};
+
+class Q_WAYLAND_CLIENT_EXPORT QWaylandXdgToplevelDecorationV1 : public QtWayland::zxdg_toplevel_decoration_v1
+{
+public:
+    QWaylandXdgToplevelDecorationV1(::zxdg_toplevel_decoration_v1 *decoration);
+    ~QWaylandXdgToplevelDecorationV1() override;
+    void requestMode(mode mode);
+    void unsetMode();
+    mode pending() const;
+
+protected:
+    void zxdg_toplevel_decoration_v1_configure(uint32_t mode) override;
+
+private:
+    mode m_pending = mode_client_side;
+    mode m_requested = mode_client_side;
+    bool m_modeSet = false;
+};
+
+QT_END_NAMESPACE
+
+}
+
+#endif // QWAYLANDXDGDECORATIONV1_P_H
diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
index 12c77d80d..7dabd96f2 100644
--- a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell.cpp
@@ -54,7 +54,12 @@ QWaylandXdgSurface::Toplevel::Toplevel(QWaylandXdgSurface *xdgSurface)
     : QtWayland::xdg_toplevel(xdgSurface->get_toplevel())
     , m_xdgSurface(xdgSurface)
 {
-    requestWindowStates(xdgSurface->window()->window()->windowStates());
+    if (auto *decorationManager = m_xdgSurface->m_shell->decorationManager())
+        m_decoration = decorationManager->createToplevelDecoration(object());
+
+    QWindow *window = xdgSurface->window()->window();
+    requestWindowStates(window->windowStates());
+    requestWindowFlags(window->flags());
 }
 
 QWaylandXdgSurface::Toplevel::~Toplevel()
@@ -63,6 +68,11 @@ QWaylandXdgSurface::Toplevel::~Toplevel()
         QWaylandWindow *window = m_xdgSurface->window();
         window->display()->handleWindowDeactivated(window);
     }
+
+    // The protocol spec requires that the decoration object is deleted before xdg_toplevel.
+    delete m_decoration;
+    m_decoration = nullptr;
+
     if (isInitialized())
         destroy();
 }
@@ -91,6 +101,14 @@ void QWaylandXdgSurface::Toplevel::applyConfigure()
     m_applied = m_pending;
 }
 
+bool QWaylandXdgSurface::Toplevel::wantsDecorations()
+{
+    if (m_decoration && m_decoration->pending() == QWaylandXdgToplevelDecorationV1::mode_server_side)
+        return false;
+
+    return !(m_pending.states & Qt::WindowFullScreen);
+}
+
 void QWaylandXdgSurface::Toplevel::xdg_toplevel_configure(int32_t width, int32_t height, wl_array *states)
 {
     m_pending.size = QSize(width, height);
@@ -124,6 +142,16 @@ void QWaylandXdgSurface::Toplevel::xdg_toplevel_close()
     m_xdgSurface->m_window->window()->close();
 }
 
+void QWaylandXdgSurface::Toplevel::requestWindowFlags(Qt::WindowFlags flags)
+{
+    if (m_decoration) {
+        if (flags & Qt::FramelessWindowHint)
+            m_decoration->requestMode(QWaylandXdgToplevelDecorationV1::mode_client_side);
+        else
+            m_decoration->unsetMode();
+    }
+}
+
 void QWaylandXdgSurface::Toplevel::requestWindowStates(Qt::WindowStates states)
 {
     // Re-send what's different from the applied state
@@ -237,6 +265,12 @@ void QWaylandXdgSurface::setAppId(const QString &appId)
         m_toplevel->set_app_id(appId);
 }
 
+void QWaylandXdgSurface::setWindowFlags(Qt::WindowFlags flags)
+{
+    if (m_toplevel)
+        m_toplevel->requestWindowFlags(flags);
+}
+
 bool QWaylandXdgSurface::handleExpose(const QRegion &region)
 {
     if (!m_configured && !region.isEmpty()) {
@@ -261,7 +295,7 @@ void QWaylandXdgSurface::applyConfigure()
 
 bool QWaylandXdgSurface::wantsDecorations() const
 {
-    return m_toplevel && !(m_toplevel->m_pending.states & Qt::WindowFullScreen);
+    return m_toplevel && m_toplevel->wantsDecorations();
 }
 
 void QWaylandXdgSurface::requestWindowStates(Qt::WindowStates states)
@@ -313,13 +347,16 @@ void QWaylandXdgSurface::xdg_surface_configure(uint32_t serial)
     }
 }
 
-QWaylandXdgShell::QWaylandXdgShell(struct ::wl_registry *registry, uint32_t id, uint32_t availableVersion)
-    : QtWayland::xdg_wm_base(registry, id, qMin(availableVersion, 1u))
+QWaylandXdgShell::QWaylandXdgShell(QWaylandDisplay *display, uint32_t id, uint32_t availableVersion)
+    : QtWayland::xdg_wm_base(display->wl_registry(), id, qMin(availableVersion, 1u))
+    , m_display(display)
 {
+    display->addRegistryListener(&QWaylandXdgShell::handleRegistryGlobal, this);
 }
 
 QWaylandXdgShell::~QWaylandXdgShell()
 {
+    m_display->removeListener(&QWaylandXdgShell::handleRegistryGlobal, this);
     destroy();
 }
 
@@ -333,6 +370,14 @@ void QWaylandXdgShell::xdg_wm_base_ping(uint32_t serial)
     pong(serial);
 }
 
+void QWaylandXdgShell::handleRegistryGlobal(void *data, wl_registry *registry, uint id,
+                                            const QString &interface, uint version)
+{
+    QWaylandXdgShell *xdgShell = static_cast<QWaylandXdgShell *>(data);
+    if (interface == QLatin1String(QWaylandXdgDecorationManagerV1::interface()->name))
+        xdgShell->m_xdgDecorationManager.reset(new QWaylandXdgDecorationManagerV1(registry, id, version));
+}
+
 }
 
 QT_END_NAMESPACE
diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h
index 7fb851315..37a4a8a4c 100644
--- a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshell_p.h
@@ -54,6 +54,8 @@
 
 #include "qwayland-xdg-shell.h"
 
+#include "qwaylandxdgdecorationv1_p.h"
+
 #include <QtWaylandClient/qtwaylandclientglobal.h>
 #include <QtWaylandClient/private/qwaylandshellsurface_p.h>
 
@@ -68,6 +70,7 @@ class QWindow;
 
 namespace QtWaylandClient {
 
+class QWaylandDisplay;
 class QWaylandWindow;
 class QWaylandInputDevice;
 class QWaylandXdgShell;
@@ -84,6 +87,7 @@ public:
     bool move(QWaylandInputDevice *inputDevice) override;
     void setTitle(const QString &title) override;
     void setAppId(const QString &appId) override;
+    void setWindowFlags(Qt::WindowFlags flags) override;
 
     bool isExposed() const override { return m_configured; }
     bool handleExpose(const QRegion &) override;
@@ -103,10 +107,12 @@ private:
         ~Toplevel() override;
 
         void applyConfigure();
+        bool wantsDecorations();
 
         void xdg_toplevel_configure(int32_t width, int32_t height, wl_array *states) override;
         void xdg_toplevel_close() override;
 
+        void requestWindowFlags(Qt::WindowFlags flags);
         void requestWindowStates(Qt::WindowStates states);
         struct {
             QSize size = {0, 0};
@@ -115,6 +121,7 @@ private:
         QSize m_normalSize;
 
         QWaylandXdgSurface *m_xdgSurface = nullptr;
+        QWaylandXdgToplevelDecorationV1 *m_decoration = nullptr;
     };
 
     class Popup : public QtWayland::xdg_popup {
@@ -142,14 +149,21 @@ private:
 class Q_WAYLAND_CLIENT_EXPORT QWaylandXdgShell : public QtWayland::xdg_wm_base
 {
 public:
-    QWaylandXdgShell(struct ::wl_registry *registry, uint32_t id, uint32_t availableVersion);
+    QWaylandXdgShell(QWaylandDisplay *display, uint32_t id, uint32_t availableVersion);
+    ~QWaylandXdgShell() override;
 
+    QWaylandXdgDecorationManagerV1 *decorationManager() { return m_xdgDecorationManager.data(); }
     QWaylandXdgSurface *getXdgSurface(QWaylandWindow *window);
 
-    ~QWaylandXdgShell() override;
+protected:
+    void xdg_wm_base_ping(uint32_t serial) override;
 
 private:
-    void xdg_wm_base_ping(uint32_t serial) override;
+    static void handleRegistryGlobal(void *data, ::wl_registry *registry, uint id,
+                                     const QString &interface, uint version);
+
+    QWaylandDisplay *m_display = nullptr;
+    QScopedPointer<QWaylandXdgDecorationManagerV1> m_xdgDecorationManager;
 };
 
 QT_END_NAMESPACE
diff --git a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshellintegration.cpp b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshellintegration.cpp
index 54d5b55ed..8769d9716 100644
--- a/src/plugins/shellintegration/xdg-shell/qwaylandxdgshellintegration.cpp
+++ b/src/plugins/shellintegration/xdg-shell/qwaylandxdgshellintegration.cpp
@@ -38,6 +38,7 @@
 ****************************************************************************/
 
 #include "qwaylandxdgshellintegration_p.h"
+#include "qwaylandxdgdecorationv1_p.h"
 
 #include <QtWaylandClient/private/qwaylandwindow_p.h>
 #include <QtWaylandClient/private/qwaylanddisplay_p.h>
@@ -50,7 +51,7 @@ bool QWaylandXdgShellIntegration::initialize(QWaylandDisplay *display)
 {
     for (QWaylandDisplay::RegistryGlobal global : display->globals()) {
         if (global.interface == QLatin1String("xdg_wm_base")) {
-            m_xdgShell.reset(new QWaylandXdgShell(display->wl_registry(), global.id, global.version));
+            m_xdgShell.reset(new QWaylandXdgShell(display, global.id, global.version));
             break;
         }
     }
diff --git a/src/plugins/shellintegration/xdg-shell/xdg-shell.pro b/src/plugins/shellintegration/xdg-shell/xdg-shell.pro
index 1fabf2c64..2b1191af0 100644
--- a/src/plugins/shellintegration/xdg-shell/xdg-shell.pro
+++ b/src/plugins/shellintegration/xdg-shell/xdg-shell.pro
@@ -6,14 +6,17 @@ qtConfig(xkbcommon-evdev): \
     QMAKE_USE_PRIVATE += xkbcommon_evdev
 
 WAYLANDCLIENTSOURCES += \
+    ../../../3rdparty/protocol/xdg-decoration-unstable-v1.xml \
     ../../../3rdparty/protocol/xdg-shell.xml
 
 HEADERS += \
+    qwaylandxdgdecorationv1_p.h \
     qwaylandxdgshell_p.h \
     qwaylandxdgshellintegration_p.h \
 
 SOURCES += \
     main.cpp \
+    qwaylandxdgdecorationv1.cpp \
     qwaylandxdgshell.cpp \
     qwaylandxdgshellintegration.cpp \