Move SysFsSensor to libkstats and document it more properly

systemstats/CMakeLists.txt

@@ -4,6 +4,8 @@ set(ksgrdbackend_LIB_SRCS
     SensorContainer.cpp
     SensorPlugin.cpp
     SensorProperty.cpp
+    SysFsSensor.cpp
+
 )
 
 add_library(ksgrdbackend ${ksgrdbackend_LIB_SRCS})

systemstats/SysFsSensor.cpp

+/*
+    Copyright (c) 2020 Arjen Hiemstra <ahiemstra@heimr.nl>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+    Boston, MA 02110-1301, USA.
+*/
+
+#include "SysFsSensor.h"
+
+#include <QFile>
+
+SysFsSensor::SysFsSensor(const QString& id, const QString& path, SensorObject* parent)
+    : SensorProperty(id, parent)
+{
+    m_path = path;
+
+    m_convertFunction = [](const QByteArray &input) {
+        return std::atoll(input);
+    };
+}
+
+void SysFsSensor::setConvertFunction(const std::function<QVariant (const QByteArray &)>& function)
+{
+    m_convertFunction = function;
+}
+
+void SysFsSensor::update()
+{
+    if (!isSubscribed()) {
+        return;
+    }
+
+    QFile file(m_path);
+    if (!file.exists()) {
+        return;
+    }
+
+    if (!file.open(QIODevice::ReadOnly)) {
+        return;
+    }
+
+    auto value = file.readAll();
+    setValue(m_convertFunction(value));
+}

systemstats/SysFsSensor.h

+/*
+    Copyright (c) 2020 Arjen Hiemstra <ahiemstra@heimr.nl>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+    Boston, MA 02110-1301, USA.
+*/
+
+#pragma once
+
+#include <QObject>
+
+#include "SensorProperty.h"
+
+/**
+ * Convenience subclass of SensorProperty that reads a sysfs file and uses the result as value.
+ */
+class Q_DECL_EXPORT SysFsSensor : public SensorProperty
+{
+    Q_OBJECT
+
+public:
+    SysFsSensor(const QString &id, const QString &path, SensorObject *parent);
+
+    /**
+     * Set the function used to convert the data from sysfs to the value of this sensor.
+     *
+     * This accepts a function that takes a QByteArray and converts that to a QVariant.
+     * By default this is set to `std::atoll` or in other words, any numeric value
+     * should automatically be converted to a proper QVariant.
+     */
+    void setConvertFunction(const std::function<QVariant(const QByteArray&)> &function);
+
+    /**
+     * Update this sensor.
+     *
+     * This will cause the sensor to read sysfs and update the value from that.
+     * It should be called periodically so values are updated properly.
+     */
+    void update();
+
+private:
+    QString m_path;
+    std::function<QVariant(const QByteArray&)> m_convertFunction;
+};