QCanBusDevice: Don't return a bool value from clear()

As pointed out in the API review, this could lead to confusion
when reading statements like this:

 if (device->clear(QCanBusDevice::Input)) {
    // ...
 }

Change-Id: Ic039d3ed32f9ef8e7c3fb8b5f0659b8c9afd8038
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>

3 files changed, 12 insertions, 14 deletions

diff --git a/src/serialbus/qcanbusdevice.cpp b/src/serialbus/qcanbusdevice.cpp
index 4484225..6dc8abd 100644
--- a/src/serialbus/qcanbusdevice.cpp
+++ b/src/serialbus/qcanbusdevice.cpp
@@ -450,12 +450,12 @@ qint64 QCanBusDevice::framesToWrite() const
 
     \sa framesAvailable(), readFrame(), framesToWrite(), writeFrame(),
 */
-bool QCanBusDevice::clear(QCanBusDevice::Directions direction)
+void QCanBusDevice::clear(QCanBusDevice::Directions direction)
 {
     Q_D(QCanBusDevice);
 
     if (Q_UNLIKELY(d->state != ConnectedState))
-        return false;
+        return;
 
     if (direction & Direction::Input) {
         QMutexLocker(&d->incomingFramesGuard);
@@ -464,8 +464,6 @@ bool QCanBusDevice::clear(QCanBusDevice::Directions direction)
 
     if (direction & Direction::Output)
         d->outgoingFrames.clear();
-
-    return true;
 }
 
 /*!
diff --git a/src/serialbus/qcanbusdevice.h b/src/serialbus/qcanbusdevice.h
index 5d99e6a..a47fac4 100644
--- a/src/serialbus/qcanbusdevice.h
+++ b/src/serialbus/qcanbusdevice.h
@@ -115,7 +115,7 @@ public:
         AllDirections = Input | Output
     };
     Q_DECLARE_FLAGS(Directions, Direction)
-    bool clear(Directions direction = Direction::AllDirections);
+    void clear(Directions direction = Direction::AllDirections);
 
     virtual bool waitForFramesWritten(int msecs);
     virtual bool waitForFramesReceived(int msecs);
diff --git a/tests/auto/qcanbusdevice/tst_qcanbusdevice.cpp b/tests/auto/qcanbusdevice/tst_qcanbusdevice.cpp
index 389e013..85d445f 100644
--- a/tests/auto/qcanbusdevice/tst_qcanbusdevice.cpp
+++ b/tests/auto/qcanbusdevice/tst_qcanbusdevice.cpp
@@ -291,16 +291,15 @@ void tst_QCanBusDevice::readAll()
 
 void tst_QCanBusDevice::clearInputBuffer()
 {
-    device->disconnectDevice();
-    QVERIFY(!device->clear(QCanBusDevice::Input));
-
-    QVERIFY(device->connectDevice());
-    QTRY_VERIFY_WITH_TIMEOUT(device->state() == QCanBusDevice::ConnectedState, 5000);
+    if (device->state() != QCanBusDevice::ConnectedState) {
+        QVERIFY(device->connectDevice());
+        QTRY_VERIFY_WITH_TIMEOUT(device->state() == QCanBusDevice::ConnectedState, 5000);
+    }
 
     for (int i = 0; i < 10; ++i)
         device->triggerNewFrame();
 
-    QVERIFY(device->clear(QCanBusDevice::Input));
+    device->clear(QCanBusDevice::Input);
 
     QVERIFY(!device->framesAvailable());
 }
@@ -309,10 +308,11 @@ void tst_QCanBusDevice::clearOutputBuffer()
 {
     // this test requires buffered writing
     device->setWriteBuffered(true);
-    device->disconnectDevice();
-    QVERIFY(!device->clear(QCanBusDevice::Output));
 
-    QVERIFY(device->connectDevice());
+    if (device->state() != QCanBusDevice::ConnectedState) {
+        QVERIFY(device->connectDevice());
+        QTRY_VERIFY_WITH_TIMEOUT(device->state() == QCanBusDevice::ConnectedState, 5000);
+    }
 
     // first test buffered writing, frames will be written after some delay
     QSignalSpy spy(device.data(), &QCanBusDevice::framesWritten);