Unify input device hotplugging support for embedded

On embedded the mouse cursor will now appear and reappear regardless of
how the input handling code is loaded (via a generic plugin or compiled-in
to the platform plugin).

Instead of passing around QDeviceDiscovery instances that only works
when compiling-in the code into the platform plugin, introduce a new
internal central QInputDeviceManager. The single instance of this
provides a place to store any future input device related signals and
properties.

Also introduce mouse hotplugging support to linuxfb.

[ChangeLog][QtGui] The mouse cursor on Embedded Linux is now handling
hotplugging correctly with eglfs and linuxfb regardless of how the input
handling code is loaded (via a generic plugin or built in to the platform
plugin).

Change-Id: I147c1b04a193baf216598015264f2c06e1b20f84
Reviewed-by: Andy Nichols <andy.nichols@theqtcompany.com>

2 files changed, 64 insertions, 5 deletions

diff --git a/src/platformsupport/fbconvenience/qfbcursor.cpp b/src/platformsupport/fbconvenience/qfbcursor.cpp
index 806556b1e4..8d6a695d68 100644
--- a/src/platformsupport/fbconvenience/qfbcursor.cpp
+++ b/src/platformsupport/fbconvenience/qfbcursor.cpp
@@ -34,14 +34,47 @@
 #include "qfbcursor_p.h"
 #include "qfbscreen_p.h"
 #include <QtGui/QPainter>
+#include <QtGui/private/qguiapplication_p.h>
 
 QT_BEGIN_NAMESPACE
 
+bool QFbCursorDeviceListener::hasMouse() const
+{
+    return QGuiApplicationPrivate::inputDeviceManager()->deviceCount(QInputDeviceManager::DeviceTypePointer) > 0;
+}
+
+void QFbCursorDeviceListener::onDeviceListChanged(QInputDeviceManager::DeviceType type)
+{
+    if (type == QInputDeviceManager::DeviceTypePointer)
+        m_cursor->updateMouseStatus();
+}
+
 QFbCursor::QFbCursor(QFbScreen *screen)
-        : mScreen(screen), mDirty(false), mOnScreen(false)
+    : mVisible(true),
+      mScreen(screen),
+      mDirty(false),
+      mOnScreen(false),
+      mGraphic(0),
+      mDeviceListener(0)
 {
+    QByteArray hideCursorVal = qgetenv("QT_QPA_FB_HIDECURSOR");
+    if (!hideCursorVal.isEmpty())
+        mVisible = hideCursorVal.toInt() == 0;
+    if (!mVisible)
+        return;
+
     mGraphic = new QPlatformCursorImage(0, 0, 0, 0, 0, 0);
     setCursor(Qt::ArrowCursor);
+
+    mDeviceListener = new QFbCursorDeviceListener(this);
+    connect(QGuiApplicationPrivate::inputDeviceManager(), &QInputDeviceManager::deviceListChanged,
+            mDeviceListener, &QFbCursorDeviceListener::onDeviceListChanged);
+    updateMouseStatus();
+}
+
+QFbCursor::~QFbCursor()
+{
+    delete mDeviceListener;
 }
 
 QRect QFbCursor::getCurrentRect()
@@ -68,6 +101,9 @@ void QFbCursor::pointerEvent(const QMouseEvent & e)
 
 QRect QFbCursor::drawCursor(QPainter & painter)
 {
+    if (!mVisible)
+        return QRect();
+
     mDirty = false;
     if (mCurrentRect.isNull())
         return QRect();
@@ -131,15 +167,19 @@ void QFbCursor::changeCursor(QCursor * widgetCursor, QWindow *window)
 
 void QFbCursor::setDirty()
 {
+    if (!mVisible)
+        return;
+
     if (!mDirty) {
         mDirty = true;
         mScreen->scheduleUpdate();
     }
 }
 
-void QFbCursor::setMouseDeviceDiscovery(QDeviceDiscovery *dd)
+void QFbCursor::updateMouseStatus()
 {
-    Q_UNUSED(dd);
+    mVisible = mDeviceListener->hasMouse();
+    mScreen->setDirty(mVisible ? getCurrentRect() : lastPainted());
 }
 
 QT_END_NAMESPACE
diff --git a/src/platformsupport/fbconvenience/qfbcursor_p.h b/src/platformsupport/fbconvenience/qfbcursor_p.h
index 75501a0ff0..bec781fb21 100644
--- a/src/platformsupport/fbconvenience/qfbcursor_p.h
+++ b/src/platformsupport/fbconvenience/qfbcursor_p.h
@@ -46,11 +46,27 @@
 //
 
 #include <qpa/qplatformcursor.h>
+#include <QtGui/private/qinputdevicemanager_p.h>
 
 QT_BEGIN_NAMESPACE
 
 class QFbScreen;
-class QDeviceDiscovery;
+class QFbCursor;
+
+class QFbCursorDeviceListener : public QObject
+{
+    Q_OBJECT
+
+public:
+    QFbCursorDeviceListener(QFbCursor *cursor) : m_cursor(cursor) { }
+    bool hasMouse() const;
+
+public slots:
+    void onDeviceListChanged(QInputDeviceManager::DeviceType type);
+
+private:
+    QFbCursor *m_cursor;
+};
 
 class QFbCursor : public QPlatformCursor
 {
@@ -58,6 +74,7 @@ class QFbCursor : public QPlatformCursor
 
 public:
     QFbCursor(QFbScreen *screen);
+    ~QFbCursor();
 
     // output methods
     QRect dirtyRect();
@@ -74,7 +91,7 @@ public:
     virtual bool isOnScreen() const { return mOnScreen; }
     virtual QRect lastPainted() const { return mPrevRect; }
 
-    void setMouseDeviceDiscovery(QDeviceDiscovery *dd);
+    void updateMouseStatus();
 
 private:
     void setCursor(const uchar *data, const uchar *mask, int width, int height, int hotX, int hotY);
@@ -82,12 +99,14 @@ private:
     void setCursor(const QImage &image, int hotx, int hoty);
     QRect getCurrentRect();
 
+    bool mVisible;
     QFbScreen *mScreen;
     QRect mCurrentRect;      // next place to draw the cursor
     QRect mPrevRect;         // last place the cursor was drawn
     bool mDirty;
     bool mOnScreen;
     QPlatformCursorImage *mGraphic;
+    QFbCursorDeviceListener *mDeviceListener;
 };
 
 QT_END_NAMESPACE