Synchronize QInputDeviceManager touch device count with QTouchDevice

This ensures that the values and signals reported by QInputDeviceManager
for touch devices always have corresponding entries in the list returned
by QTouchDevice::devices().
It also adds proper QTouchDevice unregistration when the underlying
input device gets removed by the evdevtouch QPA plugin.

Change-Id: I7bdf2f7435c775d15bddce8ba1e731afdc1d948a
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

8 files changed, 120 insertions, 34 deletions

diff --git a/src/gui/kernel/qtouchdevice.cpp b/src/gui/kernel/qtouchdevice.cpp
index 9d19fa4b92..266b5308a2 100644
--- a/src/gui/kernel/qtouchdevice.cpp
+++ b/src/gui/kernel/qtouchdevice.cpp
@@ -237,6 +237,17 @@ void QTouchDevicePrivate::registerDevice(const QTouchDevice *dev)
     deviceList()->append(dev);
 }
 
+/*!
+  \internal
+  */
+void QTouchDevicePrivate::unregisterDevice(const QTouchDevice *dev)
+{
+    QMutexLocker lock(&devicesMutex);
+    bool wasRemoved = deviceList()->removeOne(dev);
+    if (wasRemoved && deviceList()->isEmpty())
+        qRemovePostRoutine(cleanupDevicesList);
+}
+
 #ifndef QT_NO_DEBUG_STREAM
 QDebug operator<<(QDebug debug, const QTouchDevice *device)
 {
diff --git a/src/gui/kernel/qtouchdevice_p.h b/src/gui/kernel/qtouchdevice_p.h
index 4aff8f2f33..63b83d33ec 100644
--- a/src/gui/kernel/qtouchdevice_p.h
+++ b/src/gui/kernel/qtouchdevice_p.h
@@ -65,6 +65,7 @@ public:
     int maxTouchPoints;
 
     static void registerDevice(const QTouchDevice *dev);
+    static void unregisterDevice(const QTouchDevice *dev);
     static bool isRegistered(const QTouchDevice *dev);
 };
 
diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp
index 91a935ad0f..faa1ff8068 100644
--- a/src/gui/kernel/qwindowsysteminterface.cpp
+++ b/src/gui/kernel/qwindowsysteminterface.cpp
@@ -486,11 +486,16 @@ bool QWindowSystemInterfacePrivate::handleWindowSystemEvent(QWindowSystemInterfa
     return accepted;
 }
 
-void QWindowSystemInterface::registerTouchDevice(QTouchDevice *device)
+void QWindowSystemInterface::registerTouchDevice(const QTouchDevice *device)
 {
     QTouchDevicePrivate::registerDevice(device);
 }
 
+void QWindowSystemInterface::unregisterTouchDevice(const QTouchDevice *device)
+{
+    QTouchDevicePrivate::unregisterDevice(device);
+}
+
 void QWindowSystemInterface::handleTouchEvent(QWindow *w, QTouchDevice *device,
                                               const QList<TouchPoint> &points, Qt::KeyboardModifiers mods)
 {
diff --git a/src/gui/kernel/qwindowsysteminterface.h b/src/gui/kernel/qwindowsysteminterface.h
index 99589e8aa1..97bd087b53 100644
--- a/src/gui/kernel/qwindowsysteminterface.h
+++ b/src/gui/kernel/qwindowsysteminterface.h
@@ -127,7 +127,8 @@ public:
         QVector<QPointF> rawPositions; // in screen coordinates
     };
 
-    static void registerTouchDevice(QTouchDevice *device);
+    static void registerTouchDevice(const QTouchDevice *device);
+    static void unregisterTouchDevice(const QTouchDevice *device);
     static void handleTouchEvent(QWindow *w, QTouchDevice *device,
                                  const QList<struct TouchPoint> &points, Qt::KeyboardModifiers mods = Qt::NoModifier);
     static void handleTouchEvent(QWindow *w, ulong timestamp, QTouchDevice *device,
diff --git a/src/platformsupport/input/evdevtouch/qevdevtouchhandler.cpp b/src/platformsupport/input/evdevtouch/qevdevtouchhandler.cpp
index 5560d910ac..ad348cc083 100644
--- a/src/platformsupport/input/evdevtouch/qevdevtouchhandler.cpp
+++ b/src/platformsupport/input/evdevtouch/qevdevtouchhandler.cpp
@@ -107,9 +107,8 @@ public:
     int m_currentSlot;
 
     int findClosestContact(const QHash<int, Contact> &contacts, int x, int y, int *dist);
-    void reportPoints();
-    void registerDevice();
     void addTouchPoint(const Contact &contact, Qt::TouchPointStates *combinedStates);
+    void reportPoints();
 
     int hw_range_x_min;
     int hw_range_x_max;
@@ -119,7 +118,6 @@ public:
     int hw_pressure_max;
     QString hw_name;
     bool m_forceToActiveWindow;
-    QTouchDevice *m_device;
     bool m_typeB;
     QTransform m_rotate;
     bool m_singleTouch;
@@ -132,23 +130,11 @@ QEvdevTouchScreenData::QEvdevTouchScreenData(QEvdevTouchScreenHandler *q_ptr, co
       hw_range_x_min(0), hw_range_x_max(0),
       hw_range_y_min(0), hw_range_y_max(0),
       hw_pressure_min(0), hw_pressure_max(0),
-      m_device(0), m_typeB(false), m_singleTouch(false)
+      m_typeB(false), m_singleTouch(false)
 {
     m_forceToActiveWindow = args.contains(QLatin1String("force_window"));
 }
 
-void QEvdevTouchScreenData::registerDevice()
-{
-    m_device = new QTouchDevice;
-    m_device->setName(hw_name);
-    m_device->setType(QTouchDevice::TouchScreen);
-    m_device->setCapabilities(QTouchDevice::Position | QTouchDevice::Area);
-    if (hw_pressure_max > hw_pressure_min)
-        m_device->setCapabilities(m_device->capabilities() | QTouchDevice::Pressure);
-
-    QWindowSystemInterface::registerTouchDevice(m_device);
-}
-
 #define LONG_BITS (sizeof(long) << 3)
 #define NUM_LONGS(bits) (((bits) + LONG_BITS - 1) / LONG_BITS)
 
@@ -160,9 +146,9 @@ static inline bool testBit(long bit, const long *array)
 #endif
 
 QEvdevTouchScreenHandler::QEvdevTouchScreenHandler(const QString &device, const QString &spec, QObject *parent)
-    : QObject(parent), m_notify(0), m_fd(-1), d(0)
+    : QObject(parent), m_notify(Q_NULLPTR), m_fd(-1), d(Q_NULLPTR), m_device(Q_NULLPTR)
 #if !defined(QT_NO_MTDEV)
-      , m_mtdev(0)
+      , m_mtdev(Q_NULLPTR)
 #endif
 {
     setObjectName(QLatin1String("Evdev Touch Handler"));
@@ -299,7 +285,7 @@ QEvdevTouchScreenHandler::QEvdevTouchScreenHandler(const QString &device, const
     if (inverty)
         d->m_rotate *= QTransform::fromTranslate(0.5, 0.5).scale(1.0, -1.0).translate(-0.5, -0.5);
 
-    d->registerDevice();
+    registerTouchDevice();
 }
 
 QEvdevTouchScreenHandler::~QEvdevTouchScreenHandler()
@@ -315,6 +301,13 @@ QEvdevTouchScreenHandler::~QEvdevTouchScreenHandler()
         QT_CLOSE(m_fd);
 
     delete d;
+
+    unregisterTouchDevice();
+}
+
+QTouchDevice *QEvdevTouchScreenHandler::touchDevice() const
+{
+    return m_device;
 }
 
 void QEvdevTouchScreenHandler::readData()
@@ -368,15 +361,44 @@ err:
             qErrnoWarning(errno, "evdevtouch: Could not read from input device");
             if (errno == ENODEV) { // device got disconnected -> stop reading
                 delete m_notify;
-                m_notify = 0;
+                m_notify = Q_NULLPTR;
+
                 QT_CLOSE(m_fd);
                 m_fd = -1;
+
+                unregisterTouchDevice();
             }
             return;
         }
     }
 }
 
+void QEvdevTouchScreenHandler::registerTouchDevice()
+{
+    if (m_device)
+        return;
+
+    m_device = new QTouchDevice;
+    m_device->setName(d->hw_name);
+    m_device->setType(QTouchDevice::TouchScreen);
+    m_device->setCapabilities(QTouchDevice::Position | QTouchDevice::Area);
+    if (d->hw_pressure_max > d->hw_pressure_min)
+        m_device->setCapabilities(m_device->capabilities() | QTouchDevice::Pressure);
+
+    QWindowSystemInterface::registerTouchDevice(m_device);
+}
+
+void QEvdevTouchScreenHandler::unregisterTouchDevice()
+{
+    if (!m_device)
+        return;
+
+    QWindowSystemInterface::unregisterTouchDevice(m_device);
+
+    delete m_device;
+    m_device = Q_NULLPTR;
+}
+
 void QEvdevTouchScreenData::addTouchPoint(const Contact &contact, Qt::TouchPointStates *combinedStates)
 {
     QWindowSystemInterface::TouchPoint tp;
@@ -639,12 +661,12 @@ void QEvdevTouchScreenData::reportPoints()
             tp.pressure = (tp.pressure - hw_pressure_min) / qreal(hw_pressure_max - hw_pressure_min);
     }
 
-    QWindowSystemInterface::handleTouchEvent(0, m_device, m_touchPoints);
+    QWindowSystemInterface::handleTouchEvent(Q_NULLPTR, q->touchDevice(), m_touchPoints);
 }
 
 
 QEvdevTouchScreenHandlerThread::QEvdevTouchScreenHandlerThread(const QString &device, const QString &spec, QObject *parent)
-    : QDaemonThread(parent), m_device(device), m_spec(spec), m_handler(0)
+    : QDaemonThread(parent), m_device(device), m_spec(spec), m_handler(Q_NULLPTR), m_touchDeviceRegistered(false)
 {
     start();
 }
@@ -658,9 +680,24 @@ QEvdevTouchScreenHandlerThread::~QEvdevTouchScreenHandlerThread()
 void QEvdevTouchScreenHandlerThread::run()
 {
     m_handler = new QEvdevTouchScreenHandler(m_device, m_spec);
+    // Report the registration to the parent thread by invoking the method asynchronously
+    QMetaObject::invokeMethod(this, "notifyTouchDeviceRegistered", Qt::QueuedConnection);
+
     exec();
+
     delete m_handler;
-    m_handler = 0;
+    m_handler = Q_NULLPTR;
+}
+
+bool QEvdevTouchScreenHandlerThread::isTouchDeviceRegistered() const
+{
+    return m_touchDeviceRegistered;
+}
+
+void QEvdevTouchScreenHandlerThread::notifyTouchDeviceRegistered()
+{
+    m_touchDeviceRegistered = true;
+    emit touchDeviceRegistered();
 }
 
 
diff --git a/src/platformsupport/input/evdevtouch/qevdevtouchhandler_p.h b/src/platformsupport/input/evdevtouch/qevdevtouchhandler_p.h
index 8e7dfe59bb..ca9756d5de 100644
--- a/src/platformsupport/input/evdevtouch/qevdevtouchhandler_p.h
+++ b/src/platformsupport/input/evdevtouch/qevdevtouchhandler_p.h
@@ -66,16 +66,22 @@ class QEvdevTouchScreenHandler : public QObject
     Q_OBJECT
 
 public:
-    explicit QEvdevTouchScreenHandler(const QString &device, const QString &spec = QString(), QObject *parent = 0);
+    explicit QEvdevTouchScreenHandler(const QString &device, const QString &spec = QString(), QObject *parent = Q_NULLPTR);
     ~QEvdevTouchScreenHandler();
 
+    QTouchDevice *touchDevice() const;
+
 private slots:
     void readData();
 
 private:
+    void registerTouchDevice();
+    void unregisterTouchDevice();
+
     QSocketNotifier *m_notify;
     int m_fd;
     QEvdevTouchScreenData *d;
+    QTouchDevice *m_device;
 #if !defined(QT_NO_MTDEV)
     mtdev *m_mtdev;
 #endif
@@ -83,16 +89,24 @@ private:
 
 class QEvdevTouchScreenHandlerThread : public QDaemonThread
 {
+    Q_OBJECT
 public:
-    explicit QEvdevTouchScreenHandlerThread(const QString &device, const QString &spec, QObject *parent = 0);
+    explicit QEvdevTouchScreenHandlerThread(const QString &device, const QString &spec, QObject *parent = Q_NULLPTR);
     ~QEvdevTouchScreenHandlerThread();
     void run() Q_DECL_OVERRIDE;
-    QEvdevTouchScreenHandler *handler() { return m_handler; }
+
+    bool isTouchDeviceRegistered() const;
+
+signals:
+    void touchDeviceRegistered();
 
 private:
+    Q_INVOKABLE void notifyTouchDeviceRegistered();
+
     QString m_device;
     QString m_spec;
     QEvdevTouchScreenHandler *m_handler;
+    bool m_touchDeviceRegistered;
 };
 
 QT_END_NAMESPACE
diff --git a/src/platformsupport/input/evdevtouch/qevdevtouchmanager.cpp b/src/platformsupport/input/evdevtouch/qevdevtouchmanager.cpp
index 98fc83700c..35a685ff21 100644
--- a/src/platformsupport/input/evdevtouch/qevdevtouchmanager.cpp
+++ b/src/platformsupport/input/evdevtouch/qevdevtouchmanager.cpp
@@ -91,17 +91,17 @@ QEvdevTouchManager::QEvdevTouchManager(const QString &key, const QString &specif
 QEvdevTouchManager::~QEvdevTouchManager()
 {
     qDeleteAll(m_activeDevices);
+    updateInputDeviceCount();
 }
 
 void QEvdevTouchManager::addDevice(const QString &deviceNode)
 {
-    qCDebug(qLcEvdevTouch) << "Adding device at" << deviceNode;
+    qCDebug(qLcEvdevTouch) << "evdevtouch: Adding device at" << deviceNode;
     QEvdevTouchScreenHandlerThread *handler;
     handler = new QEvdevTouchScreenHandlerThread(deviceNode, m_spec);
     if (handler) {
         m_activeDevices.insert(deviceNode, handler);
-        QInputDeviceManagerPrivate::get(QGuiApplicationPrivate::inputDeviceManager())->setDeviceCount(
-            QInputDeviceManager::DeviceTypeTouch, m_activeDevices.count());
+        connect(handler, &QEvdevTouchScreenHandlerThread::touchDeviceRegistered, this, &QEvdevTouchManager::updateInputDeviceCount);
     } else {
         qWarning("evdevtouch: Failed to open touch device %s", qPrintable(deviceNode));
     }
@@ -110,13 +110,28 @@ void QEvdevTouchManager::addDevice(const QString &deviceNode)
 void QEvdevTouchManager::removeDevice(const QString &deviceNode)
 {
     if (m_activeDevices.contains(deviceNode)) {
-        qCDebug(qLcEvdevTouch) << "Removing device at" << deviceNode;
+        qCDebug(qLcEvdevTouch) << "evdevtouch: Removing device at" << deviceNode;
         QEvdevTouchScreenHandlerThread *handler = m_activeDevices.value(deviceNode);
         m_activeDevices.remove(deviceNode);
-        QInputDeviceManagerPrivate::get(QGuiApplicationPrivate::inputDeviceManager())->setDeviceCount(
-            QInputDeviceManager::DeviceTypeTouch, m_activeDevices.count());
         delete handler;
+
+        updateInputDeviceCount();
     }
 }
 
+void QEvdevTouchManager::updateInputDeviceCount()
+{
+    int registeredTouchDevices = 0;
+    Q_FOREACH (QEvdevTouchScreenHandlerThread *handler, m_activeDevices) {
+        if (handler->isTouchDeviceRegistered())
+            ++registeredTouchDevices;
+    }
+
+    qCDebug(qLcEvdevTouch) << "evdevtouch: Updating QInputDeviceManager device count:" << registeredTouchDevices << " touch devices,"
+                           << m_activeDevices.count() - registeredTouchDevices << "pending handler(s)" ;
+
+    QInputDeviceManagerPrivate::get(QGuiApplicationPrivate::inputDeviceManager())->setDeviceCount(
+        QInputDeviceManager::DeviceTypeTouch, registeredTouchDevices);
+}
+
 QT_END_NAMESPACE
diff --git a/src/platformsupport/input/evdevtouch/qevdevtouchmanager_p.h b/src/platformsupport/input/evdevtouch/qevdevtouchmanager_p.h
index bf484fd88b..289c345ac4 100644
--- a/src/platformsupport/input/evdevtouch/qevdevtouchmanager_p.h
+++ b/src/platformsupport/input/evdevtouch/qevdevtouchmanager_p.h
@@ -65,6 +65,8 @@ private slots:
     void addDevice(const QString &deviceNode);
     void removeDevice(const QString &deviceNode);
 
+    void updateInputDeviceCount();
+
 private:
     QString m_spec;
     QDeviceDiscovery *m_deviceDiscovery;