Add BTLE device discovery timeout API

This timeout adjusts the BTLE device discovery. Some BTLE devices
require some time to show up in such a search. In general the platforms
use open ended search methodologies as their own usage pattern for
BTLE device discovery too. So far Qt Bluetooth limited the time
through a hardcoded value which the API user could not adjust.

Task-number: QTBUG-53012
Change-Id: Ia37cebd4015b438db998c6b4a265f563c1a2f89f
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@theqtcompany.com>
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

8 files changed, 86 insertions, 2 deletions

diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent.cpp b/src/bluetooth/qbluetoothdevicediscoveryagent.cpp
index b6faee75..b90f6b01 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent.cpp
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent.cpp
@@ -232,6 +232,49 @@ QList<QBluetoothDeviceInfo> QBluetoothDeviceDiscoveryAgent::discoveredDevices()
 }
 
 /*!
+    Sets the maximum search time for Bluetooth Low Energy device search to
+    \a timeout in milliseconds. If \a timeout is \c 0 the discovery runs
+    until \l stop() is called.
+
+    This reflects the fact that the discovery process for Bluetooth Low Energy devices
+    is mostly open ended. The platform continues to look for more devices until the search is
+    manually stopped. The timeout ensures that the search is aborted after \a timeout milliseconds.
+    Of course, it is still possible to manually abort the discovery by calling \l stop().
+
+    The new timeout value does not take effect until the device search is restarted.
+    In addition the timeout does not affect the classic Bluetooth device search. Depending on
+    the platform it may add more time to the total discovery process beyond \a timeout.
+
+    \a lowEnergyDiscoveryTimeout()
+    \since 5.8
+ */
+void QBluetoothDeviceDiscoveryAgent::setLowEnergyDiscoveryTimeout(int timeout)
+{
+    Q_D(QBluetoothDeviceDiscoveryAgent);
+
+    // cannot deliberately turn it off
+    if (d->lowEnergySearchTimeout < 0 || timeout < 0)
+        return;
+
+    d->lowEnergySearchTimeout = timeout;
+}
+
+/*!
+    Returns a timeout in milliseconds that is applied to the Bluetooth Low Energy device search.
+    A value of \c -1 implies that the platform does not support this property and the timeout for
+    the device search cannot be adjusted. A return value of \c 0
+    implies a never-ending search which must be manually stopped via \l stop().
+
+    \sa setLowEnergyDiscoveryTimeout()
+    \since 5.8
+ */
+int QBluetoothDeviceDiscoveryAgent::lowEnergyDiscoveryTimeout() const
+{
+    Q_D(const QBluetoothDeviceDiscoveryAgent);
+    return d->lowEnergySearchTimeout;
+}
+
+/*!
     Starts Bluetooth device discovery, if it is not already started.
 
     The deviceDiscovered() signal is emitted as each device is discovered. The finished() signal
diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent.h b/src/bluetooth/qbluetoothdevicediscoveryagent.h
index 954ae704..39b558af 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent.h
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent.h
@@ -91,6 +91,9 @@ public:
 
     QList<QBluetoothDeviceInfo> discoveredDevices() const;
 
+    void setLowEnergyDiscoveryTimeout(int msTimeout);
+    int lowEnergyDiscoveryTimeout() const;
+
 public Q_SLOTS:
     void start();
     void stop();
diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent_android.cpp b/src/bluetooth/qbluetoothdevicediscoveryagent_android.cpp
index 5f163dfd..1d5e2c99 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent_android.cpp
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent_android.cpp
@@ -66,6 +66,7 @@ QBluetoothDeviceDiscoveryAgentPrivate::QBluetoothDeviceDiscoveryAgentPrivate(
     leScanTimeout(0),
     pendingCancel(false),
     pendingStart(false),
+    lowEnergySearchTimeout(-1), //TODO change when implemented
     q_ptr(parent)
 {
     adapter = QAndroidJniObject::callStaticObjectMethod("android/bluetooth/BluetoothAdapter",
diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent_bluez.cpp b/src/bluetooth/qbluetoothdevicediscoveryagent_bluez.cpp
index 0243d31f..add6624d 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent_bluez.cpp
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent_bluez.cpp
@@ -68,6 +68,7 @@ QBluetoothDeviceDiscoveryAgentPrivate::QBluetoothDeviceDiscoveryAgentPrivate(
     adapterBluez5(0),
     discoveryTimer(0),
     useExtendedDiscovery(false),
+    lowEnergySearchTimeout(-1), //TODO change when implemented
     q_ptr(parent)
 {
     Q_Q(QBluetoothDeviceDiscoveryAgent);
diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent_ios.mm b/src/bluetooth/qbluetoothdevicediscoveryagent_ios.mm
index 0e4b460f..571eb793 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent_ios.mm
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent_ios.mm
@@ -101,6 +101,7 @@ private:
     bool stopPending;
 
     QScopedPointer<OSXBluetooth::DDATimerHandler> timer;
+    int lowEnergySearchTimeout;
 };
 
 namespace OSXBluetooth {
@@ -144,7 +145,8 @@ QBluetoothDeviceDiscoveryAgentPrivate::QBluetoothDeviceDiscoveryAgentPrivate(con
     lastError(QBluetoothDeviceDiscoveryAgent::NoError),
     inquiryType(QBluetoothDeviceDiscoveryAgent::GeneralUnlimitedInquiry),
     startPending(false),
-    stopPending(false)
+    stopPending(false),
+    lowEnergySearchTimeout(-1) // change when implemented
 {
     Q_UNUSED(adapter);
 
@@ -430,4 +432,19 @@ QString QBluetoothDeviceDiscoveryAgent::errorString() const
     return d_ptr->errorString;
 }
 
+int QBluetoothDeviceDiscoveryAgent::lowEnergyDiscoveryTimeout() const
+{
+    return d_ptr->lowEnergySearchTimeout;
+}
+
+void QBluetoothDeviceDiscoveryAgent::setLowEnergyDiscoveryTimeout(int timeout)
+{
+    // cannot deliberately turn it off
+    if (d_ptr->lowEnergySearchTimeout < 0 || timeout < 0)
+        return;
+
+    d_ptr->lowEnergySearchTimeout = timeout;
+    return;
+}
+
 QT_END_NAMESPACE
diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent_osx.mm b/src/bluetooth/qbluetoothdevicediscoveryagent_osx.mm
index 0ead4e36..5422d235 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent_osx.mm
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent_osx.mm
@@ -135,6 +135,7 @@ private:
     DevicesList discoveredDevices;
 
     QScopedPointer<OSXBluetooth::DDATimerHandler> timer;
+    int lowEnergySearchTimeout;
 };
 
 namespace OSXBluetooth {
@@ -180,7 +181,8 @@ QBluetoothDeviceDiscoveryAgentPrivate::QBluetoothDeviceDiscoveryAgentPrivate(con
     startPending(false),
     stopPending(false),
     lastError(QBluetoothDeviceDiscoveryAgent::NoError),
-    inquiryType(QBluetoothDeviceDiscoveryAgent::GeneralUnlimitedInquiry)
+    inquiryType(QBluetoothDeviceDiscoveryAgent::GeneralUnlimitedInquiry),
+    lowEnergySearchTimeout(-1) // change when implemented
 {
     Q_ASSERT_X(q != Q_NULLPTR, Q_FUNC_INFO, "invalid q_ptr (null)");
 
@@ -624,4 +626,19 @@ QString QBluetoothDeviceDiscoveryAgent::errorString() const
     return d_ptr->errorString;
 }
 
+void QBluetoothDeviceDiscoveryAgent::setLowEnergyDiscoveryTimeout(int timeout)
+{
+    // cannot deliberately turn it off
+    if (d_ptr->lowEnergySearchTimeout < 0 || timeout < 0)
+        return;
+
+    d_ptr->lowEnergySearchTimeout = timeout;
+    return;
+}
+
+int QBluetoothDeviceDiscoveryAgent::lowEnergyDiscoveryTimeout() const
+{
+    return d_ptr->lowEnergySearchTimeout;
+}
+
 QT_END_NAMESPACE
diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent_p.cpp b/src/bluetooth/qbluetoothdevicediscoveryagent_p.cpp
index f7780722..85be8233 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent_p.cpp
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent_p.cpp
@@ -55,6 +55,7 @@ QBluetoothDeviceDiscoveryAgentPrivate::QBluetoothDeviceDiscoveryAgentPrivate(
                 QBluetoothDeviceDiscoveryAgent *parent)
     :   inquiryType(QBluetoothDeviceDiscoveryAgent::GeneralUnlimitedInquiry),
         lastError(QBluetoothDeviceDiscoveryAgent::NoError),
+        lowEnergySearchTimeout(-1),
         q_ptr(parent)
 {
     Q_UNUSED(deviceAdapter);
diff --git a/src/bluetooth/qbluetoothdevicediscoveryagent_p.h b/src/bluetooth/qbluetoothdevicediscoveryagent_p.h
index f49ff8b7..f97c2f42 100644
--- a/src/bluetooth/qbluetoothdevicediscoveryagent_p.h
+++ b/src/bluetooth/qbluetoothdevicediscoveryagent_p.h
@@ -155,6 +155,7 @@ private:
     QTimer extendedDiscoveryTimer;
 #endif
 
+    int lowEnergySearchTimeout;
     QBluetoothDeviceDiscoveryAgent *q_ptr;
 };