eglfs: Mouse hotplugging support

On Embedded Linux with libudev support hotplugging was already working,
except that the mouse cursor was not shown and hidden. This is now
corrected so that the cursor disappears when all mice become disconnected
and reappears if a mouse gets plugged in later on.

[ChangeLog][QtGui] Mouse hotplugging is now fully supported in eglfs
when running on Embedded Linux systems with libudev support enabled.

Task-number: QTBUG-36374
Change-Id: Iec7c1557ba6085e3958dd357460cc032896fb174
Reviewed-by: Andy Nichols <andy.nichols@digia.com>

1 files changed, 45 insertions, 7 deletions

diff --git a/src/platformsupport/eglconvenience/qeglplatformcursor.cpp b/src/platformsupport/eglconvenience/qeglplatformcursor.cpp
index 55590dbc9e..1c87e1d27d 100644
--- a/src/platformsupport/eglconvenience/qeglplatformcursor.cpp
+++ b/src/platformsupport/eglconvenience/qeglplatformcursor.cpp
@@ -39,7 +39,6 @@
 **
 ****************************************************************************/
 
-#include "qeglplatformcursor_p.h"
 #include <qpa/qwindowsysteminterface.h>
 #include <QtGui/QOpenGLContext>
 #include <QtGui/QOpenGLShaderProgram>
@@ -50,6 +49,9 @@
 
 #include <QtPlatformSupport/private/qdevicediscovery_p.h>
 
+#include "qeglplatformcursor_p.h"
+#include "qeglplatformintegration_p.h"
+
 QT_BEGIN_NAMESPACE
 
 /*!
@@ -66,15 +68,12 @@ QEGLPlatformCursor::QEGLPlatformCursor(QPlatformScreen *screen)
       m_program(0),
       m_vertexCoordEntry(0),
       m_textureCoordEntry(0),
-      m_textureEntry(0)
+      m_textureEntry(0),
+      m_deviceListener(0)
 {
     QByteArray hideCursorVal = qgetenv("QT_QPA_EGLFS_HIDECURSOR");
-    if (hideCursorVal.isEmpty()) {
-        QScopedPointer<QDeviceDiscovery> dis(QDeviceDiscovery::create(QDeviceDiscovery::Device_Mouse));
-        m_visible = !dis->scanConnectedDevices().isEmpty();
-    } else {
+    if (!hideCursorVal.isEmpty())
         m_visible = hideCursorVal.toInt() == 0;
-    }
     if (!m_visible)
         return;
 
@@ -92,6 +91,45 @@ QEGLPlatformCursor::QEGLPlatformCursor(QPlatformScreen *screen)
 QEGLPlatformCursor::~QEGLPlatformCursor()
 {
     resetResources();
+    delete m_deviceListener;
+}
+
+void QEGLPlatformCursor::setMouseDeviceDiscovery(QDeviceDiscovery *dd)
+{
+    if (m_visible && dd) {
+        m_deviceListener = new QEGLPlatformCursorDeviceListener(dd, this);
+        updateMouseStatus();
+    }
+}
+
+void QEGLPlatformCursor::updateMouseStatus()
+{
+    m_visible = m_deviceListener->hasMouse();
+}
+
+QEGLPlatformCursorDeviceListener::QEGLPlatformCursorDeviceListener(QDeviceDiscovery *dd, QEGLPlatformCursor *cursor)
+    : m_cursor(cursor)
+{
+    m_mouseCount = dd->scanConnectedDevices().count();
+    connect(dd, SIGNAL(deviceDetected(QString)), SLOT(onDeviceAdded()));
+    connect(dd, SIGNAL(deviceRemoved(QString)), SLOT(onDeviceRemoved()));
+}
+
+bool QEGLPlatformCursorDeviceListener::hasMouse() const
+{
+    return m_mouseCount > 0;
+}
+
+void QEGLPlatformCursorDeviceListener::onDeviceAdded()
+{
+    ++m_mouseCount;
+    m_cursor->updateMouseStatus();
+}
+
+void QEGLPlatformCursorDeviceListener::onDeviceRemoved()
+{
+    --m_mouseCount;
+    m_cursor->updateMouseStatus();
 }
 
 void QEGLPlatformCursor::resetResources()