Fix crashing btchat example when selecting remote devicev5.4.1

The example immidiately destroys the QBluetoothServiceDiscoveryAgent
when the user selects a remote chat service from the remote selector
dialog. This may happen even when the scheduled QtConcurrent call
to runSdpScan() was still pending. The subsequent signal callback into
the deleted parent caused a crash.

Unfortunately QtConcurrent::run() returns a QFuture which does not
permit stopping the pending thread execution. Therefore the runSdpScan()
had to be rewritten using QProcess to properly destruct pending
calls.

Change-Id: I1ed5e147feb94a26240901a02d836056eddabbf6
Reviewed-by: Timur Pocheptsov <Timur.Pocheptsov@digia.com>
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/src/bluetooth/qbluetoothservicediscoveryagent_p.h b/src/bluetooth/qbluetoothservicediscoveryagent_p.h
index ea985627..3b9c0a42 100644
--- a/src/bluetooth/qbluetoothservicediscoveryagent_p.h
+++ b/src/bluetooth/qbluetoothservicediscoveryagent_p.h
@@ -58,6 +58,7 @@ class OrgBluezManagerInterface;
 class OrgBluezAdapterInterface;
 class OrgBluezDeviceInterface;
 class OrgFreedesktopDBusObjectManagerInterface;
+#include <QtCore/qprocess.h>
 
 QT_BEGIN_NAMESPACE
 class QDBusPendingCallWatcher;
@@ -127,6 +128,7 @@ public:
     void _q_discoverGattCharacteristics(QDBusPendingCallWatcher *watcher);
     void _q_discoveredGattCharacteristic(QDBusPendingCallWatcher *watcher);
     */
+    void _q_sdpScannerDone(int exitCode, QProcess::ExitStatus status);
     void _q_finishSdpScan(QBluetoothServiceDiscoveryAgent::Error errorCode,
                           const QString &errorDescription,
                           const QStringList &xmlRecords);
@@ -147,8 +149,9 @@ private:
 
 #ifdef QT_BLUEZ_BLUETOOTH
     void startBluez5(const QBluetoothAddress &address);
-    void runSdpScan(const QBluetoothAddress &remoteAddress,
+    void runExternalSdpScan(const QBluetoothAddress &remoteAddress,
                     const QBluetoothAddress localAddress);
+    void sdpScannerDone(int exitCode, QProcess::ExitStatus exitStatus);
     QVariant readAttributeValue(QXmlStreamReader &xml);
     QBluetoothServiceInfo parseServiceXml(const QString& xml);
     void performMinimalServiceDiscovery(const QBluetoothAddress &deviceAddress);
@@ -195,6 +198,7 @@ private:
     OrgFreedesktopDBusObjectManagerInterface *managerBluez5;
     OrgBluezAdapterInterface *adapter;
     OrgBluezDeviceInterface *device;
+    QProcess *sdpScannerProcess;
 #endif
 
 #ifdef QT_ANDROID_BLUETOOTH