SCNetworkReachability based backend for QNetworkInformation

For macOS/iOS. Based on the code Timur wrote for QNetworkStatusMonitor,
and uses QNetworkConnectionMonitor. It has less detail than the other
backends which is unfortunate but should be fine!

Pick-to: dev
Task-number: QTBUG-86966
Change-Id: I0d5930d539f9668f001d6f85c86c9df0803d0f60
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

src/network/kernel/qnetconmonitor_p.h

@@ -61,7 +61,7 @@
 QT_BEGIN_NAMESPACE
 
 class QNetworkConnectionMonitorPrivate;
-class Q_AUTOTEST_EXPORT QNetworkConnectionMonitor : public QObject
+class Q_NETWORK_EXPORT QNetworkConnectionMonitor : public QObject
 {
     Q_OBJECT
 

src/plugins/networkinformationbackends/CMakeLists.txt

@@ -5,3 +5,7 @@ endif()
 if(LINUX)
     add_subdirectory(networkmanager)
 endif()
+
+if(APPLE)
+    add_subdirectory(scnetworkreachability)
+endif()

src/plugins/networkinformationbackends/scnetworkreachability/CMakeLists.txt

@@ -0,0 +1,10 @@
+qt_internal_add_plugin(QSCNetworkReachabilityNetworkInformationBackend
+    OUTPUT_NAME scnetworkreachabilitynetworkinformationbackend
+    TYPE networkinformationbackends
+    DEFAULT_IF APPLE
+    SOURCES
+        qscnetworkreachabilitynetworkinformationbackend.mm
+    PUBLIC_LIBRARIES
+        Qt::NetworkPrivate
+        ${FWSystemConfiguration}
+)

src/plugins/networkinformationbackends/scnetworkreachability/qscnetworkreachabilitynetworkinformationbackend.mm

@@ -0,0 +1,145 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtNetwork module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtNetwork/private/qnetworkinformation_p.h>
+
+#include <QtNetwork/private/qnetconmonitor_p.h>
+
+#include <QtCore/qglobal.h>
+#include <QtCore/private/qobject_p.h>
+
+QT_BEGIN_NAMESPACE
+Q_DECLARE_LOGGING_CATEGORY(lcNetInfoSCR)
+Q_LOGGING_CATEGORY(lcNetInfoSCR, "qt.network.info.scnetworkreachability");
+
+
+static QString backendName = QStringLiteral("scnetworkreachability");
+
+class QSCNetworkReachabilityNetworkInformationBackend : public QNetworkInformationBackend
+{
+    Q_OBJECT
+public:
+    QSCNetworkReachabilityNetworkInformationBackend();
+    ~QSCNetworkReachabilityNetworkInformationBackend();
+
+    QString name() const override { return backendName; }
+    QNetworkInformation::Features featuresSupported() const override
+    {
+        return featuresSupportedStatic();
+    }
+
+    static QNetworkInformation::Features featuresSupportedStatic()
+    {
+        return QNetworkInformation::Features(QNetworkInformation::Feature::Reachability);
+    }
+
+private Q_SLOTS:
+    void reachabilityChanged(bool isOnline);
+
+private:
+    Q_DISABLE_COPY_MOVE(QSCNetworkReachabilityNetworkInformationBackend);
+
+    QNetworkConnectionMonitor ipv4Probe;
+    QNetworkConnectionMonitor ipv6Probe;
+};
+
+class QSCNetworkReachabilityNetworkInformationBackendFactory : public QNetworkInformationBackendFactory
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID QNetworkInformationBackendFactory_iid)
+    Q_INTERFACES(QNetworkInformationBackendFactory)
+public:
+    QSCNetworkReachabilityNetworkInformationBackendFactory() = default;
+    ~QSCNetworkReachabilityNetworkInformationBackendFactory() = default;
+    QString name() const override { return backendName; }
+    QNetworkInformation::Features featuresSupported() const override
+    {
+        return QSCNetworkReachabilityNetworkInformationBackend::featuresSupportedStatic();
+    }
+
+    QNetworkInformationBackend *create(QNetworkInformation::Features requiredFeatures) const override
+    {
+        if ((requiredFeatures & featuresSupported()) != requiredFeatures)
+            return nullptr;
+        return new QSCNetworkReachabilityNetworkInformationBackend();
+    }
+
+private:
+    Q_DISABLE_COPY_MOVE(QSCNetworkReachabilityNetworkInformationBackendFactory);
+};
+
+QSCNetworkReachabilityNetworkInformationBackend::QSCNetworkReachabilityNetworkInformationBackend()
+{
+    bool isOnline = false;
+    if (ipv4Probe.setTargets(QHostAddress::AnyIPv4, {})) {
+        // We manage to create SCNetworkReachabilityRef for IPv4, let's
+        // read the last known state then!
+        isOnline |= ipv4Probe.isReachable();
+        ipv4Probe.startMonitoring();
+    }
+
+    if (ipv6Probe.setTargets(QHostAddress::AnyIPv6, {})) {
+        // We manage to create SCNetworkReachability ref for IPv6, let's
+        // read the last known state then!
+        isOnline |= ipv6Probe.isReachable();
+        ipv6Probe.startMonitoring();
+    }
+    reachabilityChanged(isOnline);
+
+    connect(&ipv4Probe, &QNetworkConnectionMonitor::reachabilityChanged, this,
+            &QSCNetworkReachabilityNetworkInformationBackend::reachabilityChanged,
+            Qt::QueuedConnection);
+    connect(&ipv6Probe, &QNetworkConnectionMonitor::reachabilityChanged, this,
+            &QSCNetworkReachabilityNetworkInformationBackend::reachabilityChanged,
+            Qt::QueuedConnection);
+}
+
+QSCNetworkReachabilityNetworkInformationBackend::~QSCNetworkReachabilityNetworkInformationBackend()
+{
+}
+
+void QSCNetworkReachabilityNetworkInformationBackend::reachabilityChanged(bool isOnline)
+{
+    setReachability(isOnline ? QNetworkInformation::Reachability::Online
+                             : QNetworkInformation::Reachability::Disconnected);
+}
+
+QT_END_NAMESPACE
+
+#include "qscnetworkreachabilitynetworkinformationbackend.moc"