QPlatformWindow: change API for QPlatformWindow::setWindowState

The current implementation requests the platform window to set
the window state if it can, and return the actual window state
back.

The problem with this approach is that the platform window is created
as late as possible, so a call to QWindow::setWindowState would in
many (most?) cases never be forwarded to the platform window (instead,
the platform window is responsible to check the current window state
upon creation). As such, the window state might be left unsynched with
the platform window.

This patch suggests removing the return value from
QPlatformWindow::setWindowState. This will at least be consistent, so
that setting/getting state would produce the same result independent of
delayed window creation. If needed, we can later add new API to
QPlatformIntegration or QPlatformWindow for querying supported/actual
window state.

Change-Id: Ie43f56169656854a765ce88b47a808f8f3d51bb4
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Thomas McGuire <thomas.mcguire@kdab.com>
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>

15 files changed, 18 insertions, 101 deletions

diff --git a/src/gui/kernel/qplatformwindow.cpp b/src/gui/kernel/qplatformwindow.cpp
index 27dfd7cf40..2bc6b01b3e 100644
--- a/src/gui/kernel/qplatformwindow.cpp
+++ b/src/gui/kernel/qplatformwindow.cpp
@@ -213,13 +213,12 @@ QPoint QPlatformWindow::mapFromGlobal(const QPoint &pos) const
 
 /*!
     Requests setting the window state of this surface
-    to \a type. Returns the actual state set.
+    to \a type.
 
     Qt::WindowActive can be ignored.
 */
-Qt::WindowState QPlatformWindow::setWindowState(Qt::WindowState)
+void QPlatformWindow::setWindowState(Qt::WindowState)
 {
-    return Qt::WindowNoState;
 }
 
 /*!
diff --git a/src/gui/kernel/qplatformwindow.h b/src/gui/kernel/qplatformwindow.h
index 2b2d227fcf..12650d6073 100644
--- a/src/gui/kernel/qplatformwindow.h
+++ b/src/gui/kernel/qplatformwindow.h
@@ -91,7 +91,7 @@ public:
 
     virtual void setVisible(bool visible);
     virtual void setWindowFlags(Qt::WindowFlags flags);
-    virtual Qt::WindowState setWindowState(Qt::WindowState state);
+    virtual void setWindowState(Qt::WindowState state);
 
     virtual WId winId() const;
     virtual void setParent(const QPlatformWindow *window);
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 39a6603c4b..4f1610cb21 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -828,9 +828,8 @@ void QWindow::setWindowState(Qt::WindowState state)
 
     Q_D(QWindow);
     if (d->platformWindow)
-        d->windowState = d->platformWindow->setWindowState(state);
-    else
-        d->windowState = state;
+        d->platformWindow->setWindowState(state);
+    d->windowState = state;
 }
 
 /*!
diff --git a/src/plugins/platforms/cocoa/qcocoawindow.h b/src/plugins/platforms/cocoa/qcocoawindow.h
index 3c6dd96424..d5dbe58de9 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.h
+++ b/src/plugins/platforms/cocoa/qcocoawindow.h
@@ -99,7 +99,7 @@ public:
     void setCocoaGeometry(const QRect &rect);
     void setVisible(bool visible);
     void setWindowFlags(Qt::WindowFlags flags);
-    Qt::WindowState setWindowState(Qt::WindowState state);
+    void setWindowState(Qt::WindowState state);
     void setWindowTitle(const QString &title);
     void setWindowFilePath(const QString &filePath);
     void setWindowIcon(const QIcon &icon);
diff --git a/src/plugins/platforms/cocoa/qcocoawindow.mm b/src/plugins/platforms/cocoa/qcocoawindow.mm
index c658a8d777..93d566da3b 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.mm
+++ b/src/plugins/platforms/cocoa/qcocoawindow.mm
@@ -400,12 +400,10 @@ void QCocoaWindow::setWindowFlags(Qt::WindowFlags flags)
     m_windowFlags = flags;
 }
 
-Qt::WindowState QCocoaWindow::setWindowState(Qt::WindowState state)
+void QCocoaWindow::setWindowState(Qt::WindowState state)
 {
     if ([m_nsWindow isVisible])
         syncWindowState(state);  // Window state set for hidden windows take effect when show() is called.
-
-    return state;
 }
 
 void QCocoaWindow::setWindowTitle(const QString &title)
diff --git a/src/plugins/platforms/eglfs/qeglfswindow.cpp b/src/plugins/platforms/eglfs/qeglfswindow.cpp
index 9822262127..036b26a165 100644
--- a/src/plugins/platforms/eglfs/qeglfswindow.cpp
+++ b/src/plugins/platforms/eglfs/qeglfswindow.cpp
@@ -117,10 +117,9 @@ void QEglFSWindow::setGeometry(const QRect &)
     QPlatformWindow::setGeometry(rect);
 }
 
-Qt::WindowState QEglFSWindow::setWindowState(Qt::WindowState)
+void QEglFSWindow::setWindowState(Qt::WindowState)
 {
     setGeometry(QRect());
-    return Qt::WindowFullScreen;
 }
 
 WId QEglFSWindow::winId() const
diff --git a/src/plugins/platforms/eglfs/qeglfswindow.h b/src/plugins/platforms/eglfs/qeglfswindow.h
index c9ef60ac9c..40a38fcb26 100644
--- a/src/plugins/platforms/eglfs/qeglfswindow.h
+++ b/src/plugins/platforms/eglfs/qeglfswindow.h
@@ -56,7 +56,7 @@ public:
     ~QEglFSWindow();
 
     void setGeometry(const QRect &);
-    Qt::WindowState setWindowState(Qt::WindowState state);
+    void setWindowState(Qt::WindowState state);
     WId winId() const;
 
     EGLSurface surface() const { return m_surface; }
diff --git a/src/plugins/platforms/qnx/qqnxwindow.cpp b/src/plugins/platforms/qnx/qqnxwindow.cpp
index 9dd8ad7a71..097b5788f6 100644
--- a/src/plugins/platforms/qnx/qqnxwindow.cpp
+++ b/src/plugins/platforms/qnx/qqnxwindow.cpp
@@ -580,13 +580,13 @@ void QQnxWindow::requestActivateWindow()
 }
 
 
-Qt::WindowState QQnxWindow::setWindowState(Qt::WindowState state)
+void QQnxWindow::setWindowState(Qt::WindowState state)
 {
     qWindowDebug() << Q_FUNC_INFO << "state =" << state;
 
     // Prevent two calls with Qt::WindowFullScreen from changing m_unmaximizedGeometry
     if (m_windowState == state)
-        return state;
+        return;
 
     switch (state) {
 
@@ -594,7 +594,7 @@ Qt::WindowState QQnxWindow::setWindowState(Qt::WindowState state)
     // WindowActive is not an accepted parameter according to the docs
     case Qt::WindowMinimized:
     case Qt::WindowActive:
-        return m_windowState;
+        return;
 
     case Qt::WindowMaximized:
     case Qt::WindowFullScreen:
@@ -609,7 +609,6 @@ Qt::WindowState QQnxWindow::setWindowState(Qt::WindowState state)
     }
 
     m_windowState = state;
-    return state;
 }
 
 void QQnxWindow::gainedFocus()
diff --git a/src/plugins/platforms/qnx/qqnxwindow.h b/src/plugins/platforms/qnx/qqnxwindow.h
index d79c6785dd..90226bb9a4 100644
--- a/src/plugins/platforms/qnx/qqnxwindow.h
+++ b/src/plugins/platforms/qnx/qqnxwindow.h
@@ -101,7 +101,7 @@ public:
     void raise();
     void lower();
     void requestActivateWindow();
-    Qt::WindowState setWindowState(Qt::WindowState state);
+    void setWindowState(Qt::WindowState state);
 
     void gainedFocus();
 
diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index a31b09d2bf..fc3566660a 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -1235,13 +1235,12 @@ void QWindowsWindow::handleWindowStateChange(Qt::WindowState state)
     QWindowSystemInterface::handleWindowStateChanged(window(), state);
 }
 
-Qt::WindowState QWindowsWindow::setWindowState(Qt::WindowState state)
+void QWindowsWindow::setWindowState(Qt::WindowState state)
 {
     if (m_data.hwnd) {
         setWindowState_sys(state);
         m_windowState = state;
     }
-    return state;
 }
 
 bool QWindowsWindow::isFullScreen_sys() const
diff --git a/src/plugins/platforms/windows/qwindowswindow.h b/src/plugins/platforms/windows/qwindowswindow.h
index 5d898a2d41..978d1d5a53 100644
--- a/src/plugins/platforms/windows/qwindowswindow.h
+++ b/src/plugins/platforms/windows/qwindowswindow.h
@@ -160,7 +160,7 @@ public:
     virtual QPoint mapFromGlobal(const QPoint &pos) const;
 
     virtual void setWindowFlags(Qt::WindowFlags flags);
-    virtual Qt::WindowState setWindowState(Qt::WindowState state);
+    virtual void setWindowState(Qt::WindowState state);
 
     HWND handle() const { return m_data.hwnd; }
 
diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index cefe1a7786..bab1884a9a 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -847,10 +847,10 @@ void QXcbWindow::changeNetWmState(bool set, xcb_atom_t one, xcb_atom_t two)
     Q_XCB_CALL(xcb_send_event(xcb_connection(), 0, m_screen->root(), XCB_EVENT_MASK_STRUCTURE_NOTIFY | XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT, (const char *)&event));
 }
 
-Qt::WindowState QXcbWindow::setWindowState(Qt::WindowState state)
+void QXcbWindow::setWindowState(Qt::WindowState state)
 {
     if (state == m_windowState)
-        return state;
+        return;
 
     // unset old state
     switch (m_windowState) {
@@ -905,7 +905,6 @@ Qt::WindowState QXcbWindow::setWindowState(Qt::WindowState state)
     connection()->sync();
 
     m_windowState = state;
-    return m_windowState;
 }
 
 void QXcbWindow::setNetWmWindowFlags(Qt::WindowFlags flags)
diff --git a/src/plugins/platforms/xcb/qxcbwindow.h b/src/plugins/platforms/xcb/qxcbwindow.h
index e2f62401dc..bd4d18a175 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.h
+++ b/src/plugins/platforms/xcb/qxcbwindow.h
@@ -82,7 +82,7 @@ public:
 
     void setVisible(bool visible);
     void setWindowFlags(Qt::WindowFlags flags);
-    Qt::WindowState setWindowState(Qt::WindowState state);
+    void setWindowState(Qt::WindowState state);
     WId winId() const;
     void setParent(const QPlatformWindow *window);
 
diff --git a/src/widgets/kernel/qwidget_p.h b/src/widgets/kernel/qwidget_p.h
index c3a1d27709..8aba276966 100644
--- a/src/widgets/kernel/qwidget_p.h
+++ b/src/widgets/kernel/qwidget_p.h
@@ -803,8 +803,6 @@ public:
     static bool qt_widget_rgn(QWidget *, short, RgnHandle, bool);
     void registerTouchWindow(bool enable = true);
 #endif
-    void setMaxWindowState_helper();
-    void setFullScreenSize_helper();
     bool stealKeyboardGrab(bool grab);
     bool stealMouseGrab(bool grab);
 };
diff --git a/src/widgets/kernel/qwidget_qpa.cpp b/src/widgets/kernel/qwidget_qpa.cpp
index e7564261f9..2950c19768 100644
--- a/src/widgets/kernel/qwidget_qpa.cpp
+++ b/src/widgets/kernel/qwidget_qpa.cpp
@@ -586,33 +586,6 @@ void QWidgetPrivate::hide_sys()
         window->setVisible(false);
 }
 
-void QWidgetPrivate::setMaxWindowState_helper()
-{
-    Q_Q(QWidget);
-
-    const uint old_state = data.in_set_window_state;
-    data.in_set_window_state = 1;
-
-    const QRect desktop = qApp->desktop()->availableGeometry(qApp->desktop()->screenNumber(q));
-    q->setGeometry(desktop);
-
-    data.in_set_window_state = old_state;
-}
-
-void QWidgetPrivate::setFullScreenSize_helper()
-{
-    Q_Q(QWidget);
-
-    const uint old_state = data.in_set_window_state;
-    data.in_set_window_state = 1;
-
-    const QRect screen = qApp->desktop()->screenGeometry(qApp->desktop()->screenNumber(q));
-    q->move(screen.topLeft());
-    q->resize(screen.size());
-
-    data.in_set_window_state = old_state;
-}
-
 Qt::WindowState effectiveState(Qt::WindowStates state)
  {
      if (state & Qt::WindowMinimized)
@@ -635,7 +608,6 @@ void QWidget::setWindowState(Qt::WindowStates newstate)
 
     data->window_state = newstate;
     data->in_set_window_state = 1;
-    bool needShow = false;
     Qt::WindowState newEffectiveState = effectiveState(newstate);
     Qt::WindowState oldEffectiveState = effectiveState(oldstate);
     if (isWindow() && newEffectiveState != oldEffectiveState) {
@@ -649,54 +621,9 @@ void QWidget::setWindowState(Qt::WindowStates newstate)
 
         Q_ASSERT(windowHandle());
         windowHandle()->setWindowState(newEffectiveState);
-        bool supported = windowHandle()->windowState() == newEffectiveState;
-
-        if (!supported) {
-            const bool wasResized = testAttribute(Qt::WA_Resized);
-            const bool wasMoved = testAttribute(Qt::WA_Moved);
-
-            // undo the effects of the old emulated state
-            if (oldEffectiveState == Qt::WindowFullScreen) {
-                setParent(0, d->topData()->savedFlags);
-                needShow = true;
-            } else if (oldEffectiveState == Qt::WindowMinimized) {
-                needShow = true;
-            }
-
-            // emulate the new window state
-            if (newEffectiveState == Qt::WindowMinimized) {
-                //### not ideal...
-                hide();
-                needShow = false;
-            } else if (newEffectiveState == Qt::WindowFullScreen) {
-                d->topData()->savedFlags = windowFlags();
-                setParent(0, Qt::FramelessWindowHint | (windowFlags() & Qt::WindowStaysOnTopHint));
-                d->setFullScreenSize_helper();
-                raise();
-                needShow = true;
-            } else if (newEffectiveState == Qt::WindowMaximized) {
-                createWinId();
-                d->setMaxWindowState_helper();
-            } else if (newEffectiveState == Qt::WindowNoState) {
-                // reset old geometry
-                QRect r = d->topData()->normalGeometry;
-                if (r.width() >= 0) {
-                    d->topData()->normalGeometry = QRect(0,0,-1,-1);
-                    setGeometry(r);
-                }
-            }
-
-            // setWindowState() is not an explicit move/resize, same as the supported == true
-            // case
-            setAttribute(Qt::WA_Resized, wasResized);
-            setAttribute(Qt::WA_Moved, wasMoved);
-        }
     }
     data->in_set_window_state = 0;
 
-    if (needShow)
-        setVisible(true);
-
     if (newstate & Qt::WindowActive)
         activateWindow();