Only keep connections alive with unpaired devices when discovery is enabled

At the moment, we were keeping the connection alive with every reachable
device. While this works optimally for most use-cases, on networks with
several devices with KDE Connect, the amount of connections grows
exponentially.

Reviewed by Albert Vaca

CCBUG: 352424

core/backends/loopback/loopbacklinkprovider.cpp

@@ -25,7 +25,6 @@
 LoopbackLinkProvider::LoopbackLinkProvider()
     : identityPackage(PACKAGE_TYPE_IDENTITY)
 {
-    loopbackDeviceLink = 0;
     NetworkPackage::createIdentityPackage(&identityPackage);
 }
 
@@ -55,7 +54,6 @@ void LoopbackLinkProvider::onStop()
 {
     if (loopbackDeviceLink) {
         delete loopbackDeviceLink;
-        loopbackDeviceLink = 0;
     }
 }
 

core/backends/loopback/loopbacklinkprovider.h

@@ -23,6 +23,7 @@
 
 #include "../linkprovider.h"
 #include "loopbackdevicelink.h"
+#include <QPointer>
 
 class LoopbackLinkProvider
     : public LinkProvider
@@ -40,7 +41,7 @@ public:
     virtual void onNetworkChange();
 
 private:
-    LoopbackDeviceLink* loopbackDeviceLink;
+    QPointer<LoopbackDeviceLink> loopbackDeviceLink;
     NetworkPackage identityPackage;
     
 };

core/daemon.cpp

@@ -44,6 +44,7 @@ struct DaemonPrivate
     //Every known device
     QMap<QString, Device*> mDevices;
 
+    bool discoveryMode = false;
 };
 
 Daemon* Daemon::instance()
@@ -80,8 +81,8 @@ Daemon::Daemon(QObject *parent, bool testMode)
     Q_FOREACH (LinkProvider* a, d->mLinkProviders) {
         connect(a, SIGNAL(onConnectionReceived(NetworkPackage,DeviceLink*)),
                 this, SLOT(onNewDeviceLink(NetworkPackage,DeviceLink*)));
+        a->onStart();
     }
-    setDiscoveryEnabled(true);
 
     //Register on DBus
     QDBusConnection::sessionBus().registerService("org.kde.kdeconnect");
@@ -92,11 +93,36 @@ Daemon::Daemon(QObject *parent, bool testMode)
 
 void Daemon::setDiscoveryEnabled(bool b)
 {
-    Q_FOREACH (LinkProvider* a, d->mLinkProviders) {
-        if (b)
-            a->onStart();
-        else
-            a->onStop();
+//     qDebug() << "setting discover..." << b;
+    if (b == d->discoveryMode)
+        return;
+
+    d->discoveryMode = b;
+    if (b) {
+        forceOnNetworkChange();
+    } else {
+        cleanDevices();
+    }
+}
+
+bool Daemon::isDiscoveryEnabled() const
+{
+    return d->discoveryMode;
+}
+
+void Daemon::removeDevice(Device* device)
+{
+    d->mDevices.remove(device->id());
+    device->deleteLater();
+    Q_EMIT deviceRemoved(device->id());
+}
+
+void Daemon::cleanDevices()
+{
+    Q_FOREACH(Device* device, d->mDevices) {
+        if (!device->isPaired()) {
+            removeDevice(device);
+        }
     }
 }
 
@@ -134,31 +160,32 @@ void Daemon::onNewDeviceLink(const NetworkPackage& identityPackage, DeviceLink*
             Q_EMIT deviceVisibilityChanged(id, true);
         }
     } else {
+        Device* device = new Device(this, identityPackage, dl);
         //qCDebug(KDECONNECT_CORE) << "It is a new device";
 
-        Device* device = new Device(this, identityPackage, dl);
-        connect(device, SIGNAL(reachableStatusChanged()), this, SLOT(onDeviceStatusChanged()));
-        connect(device, SIGNAL(pairingChanged(bool)), this, SLOT(onDeviceStatusChanged()));
-        d->mDevices[id] = device;
+        if (d->discoveryMode && !device->isPaired()) {
+            device->deleteLater();
+        } else {
+            connect(device, SIGNAL(reachableStatusChanged()), this, SLOT(onDeviceStatusChanged()));
+            connect(device, SIGNAL(pairingChanged(bool)), this, SLOT(onDeviceStatusChanged()));
+            d->mDevices[id] = device;
 
-        Q_EMIT deviceAdded(id);
+            Q_EMIT deviceAdded(id);
+        }
     }
 }
 
 void Daemon::onDeviceStatusChanged()
 {
     Device* device = (Device*)sender();
-    QString id = device->id();
 
     qCDebug(KDECONNECT_CORE) << "Device" << device->name() << "status changed. Reachable:" << device->isReachable() << ". Paired: " << device->isPaired();
 
     if (!device->isReachable() && !device->isPaired()) {
         qCDebug(KDECONNECT_CORE) << "Destroying device" << device->name();
-        d->mDevices.remove(id);
-        device->deleteLater();
-        Q_EMIT deviceRemoved(id);
+        removeDevice(device);
     } else {
-        Q_EMIT deviceVisibilityChanged(id, device->isReachable());
+        Q_EMIT deviceVisibilityChanged(device->id(), device->isReachable());
     }
 
 }

core/daemon.h

@@ -37,6 +37,7 @@ class KDECONNECTCORE_EXPORT Daemon
 {
     Q_OBJECT
     Q_CLASSINFO("D-Bus Interface", "org.kde.kdeconnect.daemon")
+    Q_PROPERTY(bool discoveryEnabled READ isDiscoveryEnabled WRITE setDiscoveryEnabled)
 
 public:
     explicit Daemon(QObject *parent, bool testMode = false);
@@ -49,8 +50,9 @@ public:
      */
     static Daemon* instance();
 
-    //After calling this, signal deviceDiscovered will be triggered for each device
-    Q_SCRIPTABLE void setDiscoveryEnabled(bool b);
+    bool isDiscoveryEnabled() const;
+    void setDiscoveryEnabled(bool b);
+
     QList<Device*> devicesList() const;
 
     virtual void requestPairing(Device *d) = 0;
@@ -78,6 +80,9 @@ private Q_SLOTS:
     void onDeviceStatusChanged();
 
 private:
+    void removeDevice(Device* d);
+    void cleanDevices();
+
     QScopedPointer<struct DaemonPrivate> d;
 };
 

core/device.cpp

@@ -93,7 +93,7 @@ Device::Device(QObject* parent, const NetworkPackage& identityPackage, DeviceLin
 
 Device::~Device()
 {
-
+    qDeleteAll(m_deviceLinks);
 }
 
 bool Device::hasPlugin(const QString& name) const

kcm/kcm.cpp

@@ -104,6 +104,7 @@ KdeConnectKcm::KdeConnectKcm(QWidget *parent, const QVariantList&)
     connect(kcmUi->renameShow_button,SIGNAL(clicked()),
             this, SLOT(renameShow()));
 
+    daemon->setDiscoveryEnabled(true);
 }
 
 void KdeConnectKcm::renameShow()
@@ -133,6 +134,7 @@ void KdeConnectKcm::setRenameMode(bool b) {
 
 KdeConnectKcm::~KdeConnectKcm()
 {
+    daemon->setDiscoveryEnabled(false);
     delete kcmUi;
 }