Use real properties for QSensor::bufferSize & co

The #ifdef Q_DOC hack is not really needed and was
confusing.

In addition, expose those properties to the QML API.

As a result, the backends can now listen to the
bufferSizeChanged() signal to update the buffering
while the sensor is running. This has been implemented
for the BlackBerry platform.

Change-Id: I5239ba2a4b791cfc9f684b44ff2bc103a7b5b0da
Reviewed-by: Lorn Potter <lorn.potter@jollamobile.com>

3 files changed, 86 insertions, 13 deletions

diff --git a/src/sensors/qsensor.cpp b/src/sensors/qsensor.cpp
index 125d5924..01a4f7b7 100644
--- a/src/sensors/qsensor.cpp
+++ b/src/sensors/qsensor.cpp
@@ -1016,11 +1016,33 @@ void QSensor::setUserOrientation(int userOrientation)
 
     The property holds the maximum buffer size.
 
-    Note that this may be undefined, in which case the sensor does not support any form of buffering.
+    Note that this may be 1, in which case the sensor does not support any form of buffering.
+    In that case, isFeatureSupported(QSensor::Buffering) will also return false.
 
     \sa QSensor::bufferSize, QSensor::efficientBufferSize
 */
 
+int QSensor::maxBufferSize() const
+{
+    Q_D(const QSensor);
+    return d->maxBufferSize;
+}
+
+/*!
+    \since 5.1
+    Sets the maximum buffer size to \a maxBufferSize. This is to be called from the
+    backend.
+*/
+void QSensor::setMaxBufferSize(int maxBufferSize)
+{
+    // ### Qt 6: Remove the entire maxBufferSize property, no backend really uses it
+    Q_D(QSensor);
+    if (d->maxBufferSize != maxBufferSize) {
+        d->maxBufferSize = maxBufferSize;
+        emit maxBufferSizeChanged(maxBufferSize);
+    }
+}
+
 /*!
     \property QSensor::efficientBufferSize
 
@@ -1028,17 +1050,36 @@ void QSensor::setUserOrientation(int userOrientation)
     no particular size is most efficient). Some sensor drivers have a FIFO buffer which
     makes it more efficient to deliver the FIFO's size worth of readings at one time.
 
-    Note that this may be undefined, in which case the sensor does not support any form of buffering.
-
     \sa QSensor::bufferSize, QSensor::maxBufferSize
 */
 
+int QSensor::efficientBufferSize() const
+{
+    Q_D(const QSensor);
+    return d->efficientBufferSize;
+}
+
+/*!
+    \since 5.1
+    Sets the efficient buffer size to \a efficientBufferSize. This is to be called from the
+    backend.
+*/
+void QSensor::setEfficientBufferSize(int efficientBufferSize)
+{
+    // ### Qt 6: Remove the entire efficientBufferSize property, no backend really uses it
+    Q_D(QSensor);
+    if (d->efficientBufferSize != efficientBufferSize) {
+        d->efficientBufferSize = efficientBufferSize;
+        emit efficientBufferSizeChanged(efficientBufferSize);
+    }
+}
+
 /*!
     \property QSensor::bufferSize
 
-    This property holds the size of the buffer. By default (and if the property
-    is left undefined), the buffer size is 1, which means no buffering.
-    If the maximum buffer size is 1 (or undefined), then buffering is not supported
+    This property holds the size of the buffer. By default, the buffer size is 1,
+    which means no buffering.
+    If the maximum buffer size is 1, then buffering is not supported
     by the sensor.
 
     Setting bufferSize greater than maxBufferSize will cause maxBufferSize to be used.
@@ -1065,11 +1106,26 @@ void QSensor::setUserOrientation(int userOrientation)
     in time, for example when the event loop is blocked for too long. Without a buffer, these readings
     would simply be dropped.
 
-    The buffer size can only be changed while the sensor is not active.
-
     \sa QSensor::maxBufferSize, QSensor::efficientBufferSize
 */
 
+int QSensor::bufferSize() const
+{
+    Q_D(const QSensor);
+    return d->bufferSize;
+}
+
+void QSensor::setBufferSize(int bufferSize)
+{
+    // ### Qt 6: Currently only the Blackberry backend supports this, but only as an on/off switch.
+    //           We should consider changing this to a more appropriate API.
+    Q_D(QSensor);
+    if (d->bufferSize != bufferSize) {
+        d->bufferSize = bufferSize;
+        emit bufferSizeChanged(bufferSize);
+    }
+}
+
 // =====================================================================
 
 /*!
diff --git a/src/sensors/qsensor.h b/src/sensors/qsensor.h
index 5c47df3b..2314fb94 100644
--- a/src/sensors/qsensor.h
+++ b/src/sensors/qsensor.h
@@ -95,11 +95,9 @@ class Q_SENSORS_EXPORT QSensor : public QObject
     Q_PROPERTY(AxesOrientationMode axesOrientationMode READ axesOrientationMode WRITE setAxesOrientationMode NOTIFY axesOrientationModeChanged)
     Q_PROPERTY(int currentOrientation READ currentOrientation NOTIFY currentOrientationChanged)
     Q_PROPERTY(int userOrientation READ userOrientation WRITE setUserOrientation NOTIFY userOrientationChanged)
-#ifdef Q_QDOC
-    Q_PROPERTY(int maxBufferSize)
-    Q_PROPERTY(int efficientBufferSize)
-    Q_PROPERTY(int bufferSize)
-#endif
+    Q_PROPERTY(int maxBufferSize READ maxBufferSize NOTIFY maxBufferSizeChanged)
+    Q_PROPERTY(int efficientBufferSize READ efficientBufferSize NOTIFY efficientBufferSizeChanged)
+    Q_PROPERTY(int bufferSize READ bufferSize WRITE setBufferSize NOTIFY bufferSizeChanged)
 public:
     enum Feature {
         Buffering,
@@ -177,6 +175,15 @@ public:
     int userOrientation() const;
     void setUserOrientation(int userOrientation);
 
+    int maxBufferSize() const;
+    void setMaxBufferSize(int maxBufferSize);
+
+    int efficientBufferSize() const;
+    void setEfficientBufferSize(int efficientBufferSize);
+
+    int bufferSize() const;
+    void setBufferSize(int bufferSize);
+
 public Q_SLOTS:
     // Start receiving values from the sensor
     bool start();
@@ -196,6 +203,9 @@ Q_SIGNALS:
     void axesOrientationModeChanged(AxesOrientationMode axesOrientationMode);
     void currentOrientationChanged(int currentOrientation);
     void userOrientationChanged(int userOrientation);
+    void maxBufferSizeChanged(int maxBufferSize);
+    void efficientBufferSizeChanged(int efficientBufferSize);
+    void bufferSizeChanged(int bufferSize);
 
 protected:
     explicit QSensor(const QByteArray &type, QSensorPrivate &dd, QObject* parent = 0);
diff --git a/src/sensors/qsensor_p.h b/src/sensors/qsensor_p.h
index 9b6e7e5b..71a5b6eb 100644
--- a/src/sensors/qsensor_p.h
+++ b/src/sensors/qsensor_p.h
@@ -82,6 +82,9 @@ public:
         , axesOrientationMode(QSensor::FixedOrientation)
         , currentOrientation(0)
         , userOrientation(0)
+        , bufferSize(1)
+        , maxBufferSize(1)
+        , efficientBufferSize(1)
     {
     }
 
@@ -116,6 +119,10 @@ public:
     QSensor::AxesOrientationMode axesOrientationMode;
     int currentOrientation;
     int userOrientation;
+
+    int bufferSize;
+    int maxBufferSize;
+    int efficientBufferSize;
 };
 
 class QSensorReadingPrivate