1 files changed, 30 insertions, 152 deletions

diff --git a/src/widgets/kernel/qdesktopwidget.cpp b/src/widgets/kernel/qdesktopwidget.cpp
index dd74fbf53e..797980c7c5 100644
--- a/src/widgets/kernel/qdesktopwidget.cpp
+++ b/src/widgets/kernel/qdesktopwidget.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtWidgets module of the Qt Toolkit.
@@ -38,7 +38,6 @@
 ****************************************************************************/
 
 #include "qglobal.h"
-#include "qdesktopwidget.h"
 #include "qdesktopwidget_p.h"
 #include "qscreen.h"
 #include "qwidget_p.h"
@@ -50,109 +49,66 @@
 QT_BEGIN_NAMESPACE
 
 QDesktopScreenWidget::QDesktopScreenWidget(QScreen *screen, const QRect &geometry)
-    : QWidget(nullptr, Qt::Desktop), m_screen(screen)
+    : QWidget(nullptr, Qt::Desktop)
 {
     setVisible(false);
     if (QWindow *winHandle = windowHandle())
         winHandle->setScreen(screen);
-    setScreenGeometry(geometry);
-}
-
-void QDesktopScreenWidget::setScreenGeometry(const QRect &geometry)
-{
-    m_geometry = geometry;
     setGeometry(geometry);
 }
 
-int QDesktopScreenWidget::screenNumber() const
+QScreen *QDesktopScreenWidget::screen() const
 {
     const QDesktopWidgetPrivate *desktopWidgetP
         = static_cast<const QDesktopWidgetPrivate *>(qt_widget_private(QApplication::desktop()));
-    return desktopWidgetP->screens.indexOf(const_cast<QDesktopScreenWidget *>(this));
-}
-
-const QRect QDesktopWidgetPrivate::screenGeometry(const QWidget *widget)
-{
-    if (Q_UNLIKELY(!widget)) {
-        qWarning("QDesktopWidget::screenGeometry(): Attempt "
-                 "to get the screen geometry of a null widget");
-        return QRect();
+    for (auto it : qAsConst(desktopWidgetP->screenWidgets)) {
+        if (it.second == this)
+            return it.first;
     }
-    QRect rect = QWidgetPrivate::screenGeometry(widget);
-    if (rect.isNull())
-        return screenGeometry(screenNumber(widget));
-    else return rect;
+    return nullptr;
 }
 
-const QRect QDesktopWidgetPrivate::availableGeometry(const QWidget *widget)
+QDesktopWidgetPrivate::~QDesktopWidgetPrivate()
 {
-    if (Q_UNLIKELY(!widget)) {
-        qWarning("QDesktopWidget::availableGeometry(): Attempt "
-                 "to get the available geometry of a null widget");
-        return QRect();
-    }
-    QRect rect = QWidgetPrivate::screenGeometry(widget);
-    if (rect.isNull())
-        return availableGeometry(screenNumber(widget));
-    else
-        return rect;
+    qDeleteAll(screenWidgets.values());
 }
 
-QDesktopScreenWidget *QDesktopWidgetPrivate::widgetForScreen(QScreen *qScreen) const
-{
-    foreach (QDesktopScreenWidget *widget, screens) {
-        if (widget->assignedScreen() == qScreen)
-            return widget;
-    }
-    return nullptr;
-}
-
-void QDesktopWidgetPrivate::_q_updateScreens()
+void QDesktopWidgetPrivate::updateScreens()
 {
     Q_Q(QDesktopWidget);
     const QList<QScreen *> screenList = QGuiApplication::screens();
-    const int targetLength = screenList.length();
 
     // Re-build our screens list. This is the easiest way to later compute which signals to emit.
-    // Create new screen widgets as necessary. While iterating, keep the old list in place so
-    // that widgetForScreen works.
+    // Create new screen widgets as necessary.
     // Furthermore, we note which screens have changed, and compute the overall virtual geometry.
-    QList<QDesktopScreenWidget *> newScreens;
-    QList<int> changedScreens;
+    QFlatMap<QScreen*, QDesktopScreenWidget*> newScreenWidgets;
     QRegion virtualGeometry;
 
-    for (int i = 0; i < targetLength; ++i) {
-        QScreen *qScreen = screenList.at(i);
-        const QRect screenGeometry = qScreen->geometry();
-        QDesktopScreenWidget *screenWidget = widgetForScreen(qScreen);
-        if (screenWidget) {
-            // an old screen. update geometry and remember the index in the *new* list
-            if (screenGeometry != screenWidget->screenGeometry()) {
-                screenWidget->setScreenGeometry(screenGeometry);
-                changedScreens.push_back(i);
-            }
-        } else {
+    for (QScreen *screen : screenList) {
+        const QRect screenGeometry = screen->geometry();
+        QDesktopScreenWidget *screenWidget = screenWidgets.value(screen);
+        if (!screenWidget) {
             // a new screen, create a widget and connect the signals.
-            screenWidget = new QDesktopScreenWidget(qScreen, screenGeometry);
-            QObject::connect(qScreen, SIGNAL(geometryChanged(QRect)),
-                             q, SLOT(_q_updateScreens()), Qt::QueuedConnection);
-            QObject::connect(qScreen, SIGNAL(destroyed()),
-                             q, SLOT(_q_updateScreens()), Qt::QueuedConnection);
+            screenWidget = new QDesktopScreenWidget(screen, screenGeometry);
+            QObjectPrivate::connect(screen, &QScreen::geometryChanged,
+                                    this, &QDesktopWidgetPrivate::updateScreens, Qt::QueuedConnection);
+            QObjectPrivate::connect(screen, &QObject::destroyed,
+                                    this, &QDesktopWidgetPrivate::updateScreens, Qt::QueuedConnection);
         }
         // record all the screens and the overall geometry.
-        newScreens.push_back(screenWidget);
+        newScreenWidgets.insert(screen, screenWidget);
         virtualGeometry += screenGeometry;
     }
 
     // Now we apply the accumulated updates.
-    screens.swap(newScreens); // now [newScreens] is the old screen list
-    Q_ASSERT(screens.size() == targetLength);
+    qSwap(screenWidgets, newScreenWidgets); // now [newScreenWidgets] is the old screen list
+    Q_ASSERT(screenWidgets.size() == screenList.length());
     q->setGeometry(virtualGeometry.boundingRect());
 
     // Delete the QDesktopScreenWidget that are not used any more.
-    foreach (QDesktopScreenWidget *screen, newScreens) {
-        if (!screens.contains(screen))
-            delete screen;
+    for (auto it : qAsConst(newScreenWidgets)) {
+        if (!screenWidgets.contains(it.first))
+            delete it.second;
     }
 }
 
@@ -161,90 +117,12 @@ QDesktopWidget::QDesktopWidget()
 {
     Q_D(QDesktopWidget);
     setObjectName(QLatin1String("desktop"));
-    d->_q_updateScreens();
-    connect(qApp, SIGNAL(screenAdded(QScreen*)), this, SLOT(_q_updateScreens()));
-}
-
-QDesktopWidget::~QDesktopWidget()
-{
+    d->updateScreens();
+    QObjectPrivate::connect(qApp, &QApplication::screenAdded, d, &QDesktopWidgetPrivate::updateScreens);
 }
 
-QWidget *QDesktopWidget::screen(int screen)
-{
-    Q_D(QDesktopWidget);
-    if (screen < 0 || screen >= d->screens.length())
-        return d->screens.at(0);
-    return d->screens.at(screen);
-}
-
-const QRect QDesktopWidgetPrivate::availableGeometry(int screenNo)
-{
-    const QScreen *screen = QDesktopWidgetPrivate::screen(screenNo);
-    return screen ? screen->availableGeometry() : QRect();
-}
-
-const QRect QDesktopWidgetPrivate::screenGeometry(int screenNo)
-{
-    const QScreen *screen = QDesktopWidgetPrivate::screen(screenNo);
-    return screen ? screen->geometry() : QRect();
-}
-
-int QDesktopWidgetPrivate::screenNumber(const QWidget *w)
-{
-    if (!w)
-        return 0;
-
-    const QList<QScreen *> allScreens = QGuiApplication::screens();
-    QList<QScreen *> screens = allScreens;
-    if (screens.isEmpty()) // This should never happen
-        return 0;
-
-    // If there is more than one virtual desktop
-    if (screens.count() != screens.constFirst()->virtualSiblings().count()) {
-        // Find the root widget, get a QScreen from it and use the
-        // virtual siblings for checking the window position.
-        if (const QScreen *winScreen = qt_widget_private(const_cast<QWidget *>(w))->associatedScreen())
-            screens = winScreen->virtualSiblings();
-    }
-
-    // Get the screen number from window position using screen geometry
-    // and proper screens.
-    QRect frame = w->frameGeometry();
-    if (!w->isWindow())
-        frame.moveTopLeft(w->mapToGlobal(QPoint(0, 0)));
-
-    QScreen *widgetScreen = nullptr;
-    int largestArea = 0;
-    foreach (QScreen *screen, screens) {
-        const QRect deviceIndependentScreenGeometry =
-            QHighDpi::fromNativePixels(screen->handle()->geometry(), screen);
-        const QRect intersected = deviceIndependentScreenGeometry.intersected(frame);
-        int area = intersected.width() * intersected.height();
-        if (largestArea < area) {
-            widgetScreen = screen;
-            largestArea = area;
-        }
-    }
-    return allScreens.indexOf(widgetScreen);
-}
-
-int QDesktopWidgetPrivate::screenNumber(const QPoint &p)
-{
-    QScreen *screen = QGuiApplication::screenAt(p);
-    return screen ? QGuiApplication::screens().indexOf(screen) : 0;
-}
-
-QScreen *QDesktopWidgetPrivate::screen(int screenNo)
-{
-    QList<QScreen *> screens = QGuiApplication::screens();
-    if (screenNo == -1)
-        screenNo = 0;
-    if (screenNo < 0 || screenNo >= screens.size())
-        return nullptr;
-    return screens.at(screenNo);
-}
+QDesktopWidget::~QDesktopWidget() = default;
 
 QT_END_NAMESPACE
 
-#include "moc_qdesktopwidget.cpp"
 #include "moc_qdesktopwidget_p.cpp"