Move screen maintenance functions from QPlatformIntegration to QWSI

QWindowSystemInterface is the de facto API for any plumbing going from
the platform plugin to QtGui. Having the functions as protected members
of QPlatformIntegration was idiosyncratic, and resulted in awkward
workarounds to be able to call the functions from outside of the
QPlatformIntegration subclass.

The functions in QPlatformIntegration have been left in, but deprecated
so that platform plugins outside of qtbase have a chance to move over to
the new QWSI API before they are removed.

Change-Id: I327fec460db6b0faaf0ae2a151c20aa30dbe7182
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>

6 files changed, 90 insertions, 54 deletions

diff --git a/src/gui/kernel/qplatformintegration.cpp b/src/gui/kernel/qplatformintegration.cpp
index 7d1fcd4eeb..ac4d12b024 100644
--- a/src/gui/kernel/qplatformintegration.cpp
+++ b/src/gui/kernel/qplatformintegration.cpp
@@ -463,37 +463,16 @@ QList<int> QPlatformIntegration::possibleKeys(const QKeyEvent *) const
 }
 
 /*!
-  Should be called by the implementation whenever a new screen is added.
-
-  The first screen added will be the primary screen, used for default-created
-  windows, GL contexts, and other resources unless otherwise specified.
-
-  This adds the screen to QGuiApplication::screens(), and emits the
-  QGuiApplication::screenAdded() signal.
-
-  The screen should be deleted by calling QPlatformIntegration::destroyScreen().
+  \deprecated Use QWindowSystemInterface::handleScreenAdded instead.
 */
 void QPlatformIntegration::screenAdded(QPlatformScreen *ps, bool isPrimary)
 {
-    QScreen *screen = new QScreen(ps);
-
-    if (isPrimary) {
-        QGuiApplicationPrivate::screen_list.prepend(screen);
-    } else {
-        QGuiApplicationPrivate::screen_list.append(screen);
-    }
-    emit qGuiApp->screenAdded(screen);
-
-    if (isPrimary)
-        emit qGuiApp->primaryScreenChanged(screen);
+    QWindowSystemInterface::handleScreenAdded(ps, isPrimary);
 }
 
 /*!
-  Just removes the screen, call destroyScreen instead.
-
-  \sa destroyScreen()
+  \deprecated Use QWindowSystemInterface::handleScreenRemoved instead.
 */
-
 void QPlatformIntegration::removeScreen(QScreen *screen)
 {
     const bool wasPrimary = (!QGuiApplicationPrivate::screen_list.isEmpty() && QGuiApplicationPrivate::screen_list.at(0) == screen);
@@ -504,38 +483,19 @@ void QPlatformIntegration::removeScreen(QScreen *screen)
 }
 
 /*!
-  Should be called by the implementation whenever a screen is removed.
-
-  This removes the screen from QGuiApplication::screens(), and deletes it.
-
-  Failing to call this and manually deleting the QPlatformScreen instead may
-  lead to a crash due to a pure virtual call.
+  \deprecated Use QWindowSystemInterface::handleScreenRemoved instead.
 */
-void QPlatformIntegration::destroyScreen(QPlatformScreen *screen)
+void QPlatformIntegration::destroyScreen(QPlatformScreen *platformScreen)
 {
-    QScreen *qScreen = screen->screen();
-    removeScreen(qScreen);
-    delete qScreen;
-    delete screen;
+    QWindowSystemInterface::handleScreenRemoved(platformScreen);
 }
 
 /*!
-  Should be called whenever the primary screen changes.
-
-  When the screen specified as primary changes, this method will notify
-  QGuiApplication and emit the QGuiApplication::primaryScreenChanged signal.
- */
-
+  \deprecated Use QWindowSystemInterface::handlePrimaryScreenChanged instead.
+*/
 void QPlatformIntegration::setPrimaryScreen(QPlatformScreen *newPrimary)
 {
-    QScreen* newPrimaryScreen = newPrimary->screen();
-    int idx = QGuiApplicationPrivate::screen_list.indexOf(newPrimaryScreen);
-    Q_ASSERT(idx >= 0);
-    if (idx == 0)
-        return;
-
-    QGuiApplicationPrivate::screen_list.swap(0, idx);
-    emit qGuiApp->primaryScreenChanged(newPrimaryScreen);
+    QWindowSystemInterface::handlePrimaryScreenChanged(newPrimary);
 }
 
 QStringList QPlatformIntegration::themeNames() const
diff --git a/src/gui/kernel/qplatformintegration.h b/src/gui/kernel/qplatformintegration.h
index efb1481f6d..1179daeb32 100644
--- a/src/gui/kernel/qplatformintegration.h
+++ b/src/gui/kernel/qplatformintegration.h
@@ -190,7 +190,9 @@ public:
 #endif
     virtual void setApplicationIcon(const QIcon &icon) const;
 
-    void removeScreen(QScreen *screen);
+#if QT_DEPRECATED_SINCE(5, 12)
+    QT_DEPRECATED_X("Use QWindowSystemInterface::handleScreenRemoved") void removeScreen(QScreen *screen);
+#endif
 
     virtual void beep() const;
 
@@ -199,9 +201,11 @@ public:
 #endif
 
 protected:
-    void screenAdded(QPlatformScreen *screen, bool isPrimary = false);
-    void destroyScreen(QPlatformScreen *screen);
-    void setPrimaryScreen(QPlatformScreen *newPrimary);
+#if QT_DEPRECATED_SINCE(5, 12)
+    QT_DEPRECATED_X("Use QWindowSystemInterface::handleScreenAdded") void screenAdded(QPlatformScreen *screen, bool isPrimary = false);
+    QT_DEPRECATED_X("Use QWindowSystemInterface::handleScreenRemoved") void destroyScreen(QPlatformScreen *screen);
+    QT_DEPRECATED_X("Use QWindowSystemInterface::handlePrimaryScreenChanged") void setPrimaryScreen(QPlatformScreen *newPrimary);
+#endif
 };
 
 QT_END_NAMESPACE
diff --git a/src/gui/kernel/qplatformscreen.cpp b/src/gui/kernel/qplatformscreen.cpp
index b7b312e89e..21ae75ba8f 100644
--- a/src/gui/kernel/qplatformscreen.cpp
+++ b/src/gui/kernel/qplatformscreen.cpp
@@ -61,8 +61,11 @@ QPlatformScreen::~QPlatformScreen()
 {
     Q_D(QPlatformScreen);
     if (d->screen) {
-        qWarning("Manually deleting a QPlatformScreen. Call QPlatformIntegration::destroyScreen instead.");
+        qWarning("Manually deleting a QPlatformScreen. Call QWindowSystemInterface::handleScreenRemoved instead.");
+QT_WARNING_PUSH
+QT_WARNING_DISABLE_DEPRECATED
         QGuiApplicationPrivate::platformIntegration()->removeScreen(d->screen);
+QT_WARNING_POP
         delete d->screen;
     }
 }
diff --git a/src/gui/kernel/qscreen.h b/src/gui/kernel/qscreen.h
index 8c9b16e08e..14392d3036 100644
--- a/src/gui/kernel/qscreen.h
+++ b/src/gui/kernel/qscreen.h
@@ -169,6 +169,7 @@ private:
     friend class QPlatformIntegration;
     friend class QPlatformScreen;
     friend class QHighDpiScaling;
+    friend class QWindowSystemInterface;
 };
 
 #ifndef QT_NO_DEBUG_STREAM
diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp
index 7067ece1d8..b0f2869128 100644
--- a/src/gui/kernel/qwindowsysteminterface.cpp
+++ b/src/gui/kernel/qwindowsysteminterface.cpp
@@ -780,6 +780,70 @@ QT_DEFINE_QPA_EVENT_HANDLER(void, handleTouchCancelEvent, QWindow *window, ulong
     QWindowSystemInterfacePrivate::handleWindowSystemEvent<Delivery>(e);
 }
 
+/*!
+    Should be called by the implementation whenever a new screen is added.
+
+    The first screen added will be the primary screen, used for default-created
+    windows, GL contexts, and other resources unless otherwise specified.
+
+    This adds the screen to QGuiApplication::screens(), and emits the
+    QGuiApplication::screenAdded() signal.
+
+    The screen should be deleted by calling QWindowSystemInterface::handleScreenRemoved().
+*/
+void QWindowSystemInterface::handleScreenAdded(QPlatformScreen *ps, bool isPrimary)
+{
+    QScreen *screen = new QScreen(ps);
+
+    if (isPrimary)
+        QGuiApplicationPrivate::screen_list.prepend(screen);
+    else
+        QGuiApplicationPrivate::screen_list.append(screen);
+
+    emit qGuiApp->screenAdded(screen);
+
+    if (isPrimary)
+        emit qGuiApp->primaryScreenChanged(screen);
+}
+
+/*!
+    Should be called by the implementation whenever a screen is removed.
+
+    This removes the screen from QGuiApplication::screens(), and deletes it.
+
+    Failing to call this and manually deleting the QPlatformScreen instead may
+    lead to a crash due to a pure virtual call.
+*/
+void QWindowSystemInterface::handleScreenRemoved(QPlatformScreen *platformScreen)
+{
+QT_WARNING_PUSH
+QT_WARNING_DISABLE_DEPRECATED
+    QGuiApplicationPrivate::platformIntegration()->removeScreen(platformScreen->screen());
+QT_WARNING_POP
+
+    // Important to keep this order since the QSceen doesn't own the platform screen
+    delete platformScreen->screen();
+    delete platformScreen;
+}
+
+/*!
+    Should be called whenever the primary screen changes.
+
+    When the screen specified as primary changes, this method will notify
+    QGuiApplication and emit the QGuiApplication::primaryScreenChanged signal.
+ */
+void QWindowSystemInterface::handlePrimaryScreenChanged(QPlatformScreen *newPrimary)
+{
+    QScreen *newPrimaryScreen = newPrimary->screen();
+    int indexOfScreen = QGuiApplicationPrivate::screen_list.indexOf(newPrimaryScreen);
+    Q_ASSERT(indexOfScreen >= 0);
+    if (indexOfScreen == 0)
+        return;
+
+    QGuiApplicationPrivate::screen_list.swap(0, indexOfScreen);
+    emit qGuiApp->primaryScreenChanged(newPrimaryScreen);
+}
+
 void QWindowSystemInterface::handleScreenOrientationChange(QScreen *screen, Qt::ScreenOrientation orientation)
 {
     QWindowSystemInterfacePrivate::ScreenOrientationEvent *e =
diff --git a/src/gui/kernel/qwindowsysteminterface.h b/src/gui/kernel/qwindowsysteminterface.h
index 1dde9130ac..bf98c33a1a 100644
--- a/src/gui/kernel/qwindowsysteminterface.h
+++ b/src/gui/kernel/qwindowsysteminterface.h
@@ -233,6 +233,10 @@ public:
     static bool handleNativeEvent(QWindow *window, const QByteArray &eventType, void *message, long *result);
 
     // Changes to the screen
+    static void handleScreenAdded(QPlatformScreen *screen, bool isPrimary = false);
+    static void handleScreenRemoved(QPlatformScreen *screen);
+    static void handlePrimaryScreenChanged(QPlatformScreen *newPrimary);
+
     static void handleScreenOrientationChange(QScreen *screen, Qt::ScreenOrientation newOrientation);
     static void handleScreenGeometryChange(QScreen *screen, const QRect &newGeometry, const QRect &newAvailableGeometry);
     static void handleScreenLogicalDotsPerInchChange(QScreen *screen, qreal newDpiX, qreal newDpiY);