Added the ability to cache the last region (#2615)

* Added the ability to cache the last region

* adding cli option

* addressed typo comments and applied clang-format

src/config/cacheutils.cpp

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// SPDX-FileCopyrightText: 2021 Jeremy Borgman
+
+#include "cacheutils.h"
+#include <QDataStream>
+#include <QDir>
+#include <QFile>
+#include <QRect>
+#include <QStandardPaths>
+#include <QString>
+
+QString getCachePath()
+{
+    auto cachePath =
+      QStandardPaths::writableLocation(QStandardPaths::CacheLocation);
+    if (!QDir(cachePath).exists()) {
+        QDir().mkpath(cachePath);
+    }
+    return cachePath;
+}
+
+void setLastRegion(QRect const& newRegion)
+{
+    auto cachePath = getCachePath() + "/region.txt";
+
+    QFile file(cachePath);
+    if (file.open(QIODevice::WriteOnly)) {
+        QDataStream out(&file);
+        out << newRegion;
+        file.close();
+    }
+}
+
+QRect getLastRegion()
+{
+    auto cachePath = getCachePath() + "/region.txt";
+    QFile file(cachePath);
+
+    QRect lastRegion;
+    if (file.open(QIODevice::ReadOnly)) {
+        QDataStream input(&file);
+        input >> lastRegion;
+        file.close();
+    } else {
+        lastRegion = QRect(0, 0, 0, 0);
+    }
+
+    return lastRegion;
+}