Implement alertion state for windows.

Add QWindow::alert() and QPlatformWindow::setAlertState().
Add logic to clear alertion state when the window becomes
active. The platform plugins then only need to implement a setter
and a cheap getter and need not handle activation.

Prototypically implement X11 and Windows.

Task-number: QTBUG-30416
Change-Id: Ia70c4722d812462a21f4034b7d52735c9f2bc49c
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>

src/gui/kernel/qguiapplication.cpp

@@ -1592,6 +1592,11 @@ void QGuiApplicationPrivate::processActivatedEvent(QWindowSystemInterfacePrivate
     if (previous == newFocus)
         return;
 
+    if (newFocus)
+        if (QPlatformWindow *platformWindow = newFocus->handle())
+            if (platformWindow->isAlertState())
+                platformWindow->setAlertState(false);
+
     QObject *previousFocusObject = previous ? previous->focusObject() : 0;
 
     if (previous) {

src/gui/kernel/qplatformwindow.cpp

@@ -462,6 +462,32 @@ QString QPlatformWindow::formatWindowTitle(const QString &title, const QString &
     return fullTitle;
 }
 
+/*!
+    Reimplement this method to set whether the window demands attention
+    (for example, by flashing the taskbar icon) depending on \a enabled.
+
+    \sa isAlertState()
+    \since 5.1
+*/
+
+void QPlatformWindow::setAlertState(bool enable)
+{
+    Q_UNUSED(enable)
+}
+
+/*!
+    Reimplement this method return whether the window is in
+    an alert state.
+
+    \sa setAlertState()
+    \since 5.1
+*/
+
+bool QPlatformWindow::isAlertState() const
+{
+    return false;
+}
+
 /*!
     Helper function to get initial geometry on windowing systems which do not
     do smart positioning and also do not provide a means of centering a

src/gui/kernel/qplatformwindow.h

@@ -128,6 +128,9 @@ public:
     virtual void setFrameStrutEventsEnabled(bool enabled);
     virtual bool frameStrutEventsEnabled() const;
 
+    virtual void setAlertState(bool enabled);
+    virtual bool isAlertState() const;
+
     static QRect initialGeometry(const QWindow *w,
         const QRect &initialGeometry, int defaultWidth, int defaultHeight);
 

src/gui/kernel/qwindow.cpp

@@ -58,6 +58,7 @@
 
 #include <private/qevent_p.h>
 
+#include <QtCore/QTimer>
 #include <QtCore/QDebug>
 
 #include <QStyleHints>
@@ -2150,6 +2151,33 @@ QWindow *QWindow::fromWinId(WId id)
     return window;
 }
 
+/*!
+    Causes an alert to be shown for \a msec miliseconds. If \a msec is \c 0 (the
+    default), then the alert is shown indefinitely until the window becomes
+    active again.
+
+    In alert state, the window indicates that it demands attention, for example by
+    flashing or bouncing the taskbar entry.
+
+    \since 5.1
+*/
+
+void QWindow::alert(int msec)
+{
+    Q_D(QWindow);
+    if (!d->platformWindow || d->platformWindow->isAlertState())
+        return;
+    d->platformWindow->setAlertState(true);
+    if (d->platformWindow->isAlertState() && msec)
+        QTimer::singleShot(msec, this, SLOT(_q_clearAlert()));
+}
+
+void QWindowPrivate::_q_clearAlert()
+{
+    if (platformWindow && platformWindow->isAlertState())
+        platformWindow->setAlertState(false);
+}
+
 #ifndef QT_NO_CURSOR
 /*!
     \brief set the cursor shape for this window
@@ -2233,3 +2261,5 @@ void QWindowPrivate::applyCursor()
 #endif // QT_NO_CURSOR
 
 QT_END_NAMESPACE
+
+#include "moc_qwindow.cpp"

src/gui/kernel/qwindow.h

@@ -290,6 +290,8 @@ public Q_SLOTS:
     Q_REVISION(1) void setMaximumWidth(int w);
     Q_REVISION(1) void setMaximumHeight(int h);
 
+    void alert(int msec);
+
 Q_SIGNALS:
     void screenChanged(QScreen *screen);
     void modalityChanged(Qt::WindowModality modality);
@@ -346,6 +348,7 @@ protected:
     QWindow(QWindowPrivate &dd, QWindow *parent);
 
 private:
+    Q_PRIVATE_SLOT(d_func(), void _q_clearAlert())
     QPlatformSurface *surfaceHandle() const;
 
     Q_DISABLE_COPY(QWindow)

src/gui/kernel/qwindow_p.h

@@ -125,6 +125,7 @@ public:
     virtual QWindow *eventReceiver() { Q_Q(QWindow); return q; }
 
     void updateVisibility();
+    void _q_clearAlert();
 
     QWindow::SurfaceType surfaceType;
     Qt::WindowFlags windowFlags;

src/plugins/platforms/windows/qwindowswindow.cpp

@@ -1802,6 +1802,19 @@ QWindowsWindow *QWindowsWindow::childAt(const QPoint &clientPoint, unsigned cwex
 }
 
 #ifndef Q_OS_WINCE
+void QWindowsWindow::setAlertState(bool enabled)
+{
+    if (isAlertState() == enabled)
+        return;
+    if (enabled) {
+        alertWindow(0);
+        setFlag(AlertState);
+    } else {
+        stopAlertWindow();
+        clearFlag(AlertState);
+    }
+}
+
 void QWindowsWindow::alertWindow(int durationMs)
 {
     DWORD timeOutMs = GetCaretBlinkTime();

src/plugins/platforms/windows/qwindowswindow.h

@@ -132,7 +132,8 @@ public:
         SynchronousGeometryChangeEvent = 0x400,
         WithinSetStyle = 0x800,
         WithinDestroy = 0x1000,
-        TouchRegistered = 0x2000
+        TouchRegistered = 0x2000,
+        AlertState = 0x4000
     };
 
     struct WindowData
@@ -255,6 +256,8 @@ public:
     void setWindowIcon(const QIcon &icon);
 
 #ifndef Q_OS_WINCE
+    void setAlertState(bool enabled);
+    bool isAlertState() const { return testFlag(AlertState); }
     void alertWindow(int durationMs = 0);
     void stopAlertWindow();
 #endif

src/plugins/platforms/xcb/qxcbwindow.cpp

@@ -189,6 +189,7 @@ QXcbWindow::QXcbWindow(QWindow *window)
     , m_usingSyncProtocol(false)
     , m_deferredActivation(false)
     , m_embedded(false)
+    , m_alertState(false)
     , m_netWmUserTimeWindow(XCB_NONE)
     , m_dirtyFrameMargins(false)
 #if defined(XCB_USE_EGL)
@@ -2047,4 +2048,17 @@ void QXcbWindow::setMask(const QRegion &region)
 
 #endif // !QT_NO_SHAPE
 
+void QXcbWindow::setAlertState(bool enabled)
+{
+    if (m_alertState == enabled)
+        return;
+    const NetWmStates oldState = netWmStates();
+    m_alertState = enabled;
+    if (enabled) {
+        setNetWmStates(oldState | NetWmStateDemandsAttention);
+    } else {
+        setNetWmStates(oldState & ~NetWmStateDemandsAttention);
+    }
+}
+
 QT_END_NAMESPACE

src/plugins/platforms/xcb/qxcbwindow.h

@@ -56,7 +56,6 @@ QT_BEGIN_NAMESPACE
 class QXcbScreen;
 class QXcbEGLSurface;
 class QIcon;
-
 class QXcbWindow : public QXcbObject, public QPlatformWindow
 {
 public:
@@ -120,6 +119,9 @@ public:
     void setMask(const QRegion &region);
 #endif // !QT_NO_SHAPE
 
+    void setAlertState(bool enabled);
+    bool isAlertState() const { return m_alertState; }
+
     xcb_window_t xcb_window() const { return m_window; }
     uint depth() const { return m_depth; }
     QImage::Format imageFormat() const { return m_imageFormat; }
@@ -194,6 +196,7 @@ private:
     bool m_deferredExpose;
     bool m_configureNotifyPending;
     bool m_embedded;
+    bool m_alertState;
     xcb_window_t m_netWmUserTimeWindow;
 
     QSurfaceFormat m_format;

src/widgets/kernel/qapplication_qpa.cpp

@@ -55,6 +55,7 @@
 #include <qdesktopwidget.h>
 #include <qpa/qplatformcursor.h>
 #include <qpa/qplatformtheme.h>
+#include <qpa/qplatformwindow.h>
 
 #include <qdebug.h>
 #include <qpa/qwindowsysteminterface.h>
@@ -410,8 +411,17 @@ void QApplication::beep()
 {
 }
 
-void QApplication::alert(QWidget *, int)
+void QApplication::alert(QWidget *widget, int duration)
 {
+    if (widget) {
+       if (widget->window()->isActiveWindow()&& !widget->window()->windowState() & Qt::WindowMinimized)
+            return;
+        if (QWindow *window= QApplicationPrivate::windowForWidget(widget))
+            window->alert(duration);
+    } else {
+        foreach (QWidget *topLevel, topLevelWidgets())
+            QApplication::alert(topLevel, duration);
+    }
 }
 
 void qt_init(QApplicationPrivate *priv, int type)