Avoid bluetoothd and QtBluetooth collision when connecting to BTLE dev

BlueZ's improving support for BTLE creates a new collision when
attenpting to connect to remote BTLE devices. There can only ever be
one connection.

This patch ensures that when QtBluetooth attempts to connect we do
not have a pending BTLE connection. This could have been caused via
other QtBLuetooth based processes or applications
such as bluetoothctl or bluetoothd in general. If a connection
is pending we close the connection external to the current QtBLuetooth
instance.

This is not an ideal situation as several processes can potentially
fight over btle access. The long term solution is a port of QtBluetooth
to BlueZ's new DBus API.

Task-number: QTBUG-55150
Change-Id: I96b30ae180d1348027e8f9f09c997f44409dfc48
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

1 files changed, 170 insertions, 0 deletions

diff --git a/src/bluetooth/bluez/remotedevicemanager.cpp b/src/bluetooth/bluez/remotedevicemanager.cpp
new file mode 100644
index 00000000..f63b21e6
--- /dev/null
+++ b/src/bluetooth/bluez/remotedevicemanager.cpp
@@ -0,0 +1,170 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtBluetooth 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 <QtCore/QLoggingCategory>
+
+#include "remotedevicemanager_p.h"
+#include "bluez5_helper_p.h"
+#include "device1_bluez5_p.h"
+#include "objectmanager_p.h"
+
+QT_BEGIN_NAMESPACE
+
+Q_DECLARE_LOGGING_CATEGORY(QT_BT_BLUEZ)
+
+/*!
+ * Convenience wrapper around org.bluez.Device1 management
+ *
+ * Very simple and not thread safe.
+ */
+
+RemoteDeviceManager::RemoteDeviceManager(
+        const QBluetoothAddress &address, QObject *parent)
+    : QObject(parent), localAddress(address)
+{
+    if (!isBluez5())
+        return;
+
+    bool ok = false;
+    adapterPath = findAdapterForAddress(address, &ok);
+    if (!ok || adapterPath.isEmpty()) {
+        qCWarning(QT_BT_BLUEZ) << "Cannot initialize RemoteDeviceManager";
+    }
+}
+
+bool RemoteDeviceManager::scheduleJob(
+        JobType job, const QVector<QBluetoothAddress> &remoteDevices)
+{
+    if (adapterPath.isEmpty())
+        return false;
+
+    for (const auto& remote : remoteDevices)
+        jobQueue.push_back(std::make_pair(job, remote));
+
+    QTimer::singleShot(0, this, [this](){ runQueue(); });
+    return true;
+}
+
+void RemoteDeviceManager::runQueue()
+{
+    if (jobInProgress || adapterPath.isEmpty())
+        return;
+
+    if (jobQueue.empty())
+        return;
+
+    jobInProgress = true;
+    switch (jobQueue.front().first) {
+    case JobType::JobDisconnectDevice:
+        disconnectDevice(jobQueue.front().second);
+        break;
+    default:
+        break;
+    }
+}
+
+void RemoteDeviceManager::prepareNextJob()
+{
+    Q_ASSERT(!jobQueue.empty());
+
+    jobQueue.pop_front();
+    jobInProgress = false;
+
+    if (jobQueue.empty())
+        emit finished();
+    else
+        runQueue();
+}
+
+void RemoteDeviceManager::disconnectDevice(const QBluetoothAddress &remote)
+{
+    // collect initial set of information
+    OrgFreedesktopDBusObjectManagerInterface managerBluez5(
+                                               QStringLiteral("org.bluez"),
+                                               QStringLiteral("/"),
+                                               QDBusConnection::systemBus(), this);
+    QDBusPendingReply<ManagedObjectList> reply = managerBluez5.GetManagedObjects();
+    reply.waitForFinished();
+    if (reply.isError()) {
+        QTimer::singleShot(0, this, [this](){ prepareNextJob(); });
+        return;
+    }
+
+    bool jobStarted = false;
+    ManagedObjectList managedObjectList = reply.value();
+    for (auto it = managedObjectList.constBegin(); it != managedObjectList.constEnd(); ++it) {
+        const QDBusObjectPath &path = it.key();
+        const InterfaceList &ifaceList = it.value();
+
+        for (auto jt = ifaceList.constBegin(); jt != ifaceList.constEnd(); ++jt) {
+            const QString &iface = jt.key();
+
+            if (path.path().indexOf(adapterPath) != 0)
+                continue; //devices whose path doesn't start with same path we skip
+
+            if (iface != QStringLiteral("org.bluez.Device1"))
+                continue;
+
+            const QBluetoothAddress foundAddress(ifaceList.value(iface).value(QStringLiteral("Address")).toString());
+            if (foundAddress != remote)
+                continue;
+
+            // found the correct Device1 path
+            OrgBluezDevice1Interface* device1 = new OrgBluezDevice1Interface(QStringLiteral("org.bluez"),
+                                                                             path.path(),
+                                                                             QDBusConnection::systemBus(),
+                                                                             this);
+            QDBusPendingReply<> asyncReply = device1->Disconnect();
+            QDBusPendingCallWatcher* watcher = new QDBusPendingCallWatcher(asyncReply, this);
+            const auto watcherFinished = [this, device1](QDBusPendingCallWatcher* call) {
+                call->deleteLater();
+                device1->deleteLater();
+                prepareNextJob();
+            };
+            connect(watcher, &QDBusPendingCallWatcher::finished, this, watcherFinished);
+            jobStarted = true;
+            break;
+        }
+    }
+
+    if (!jobStarted)
+        QTimer::singleShot(0, this, [this](){ prepareNextJob(); });
+}
+
+QT_END_NAMESPACE