feat: allow specifying fallbacks to INI files

Signed-off-by: flow <flowlnlnln@gmail.com>

launcher/settings/INISettingsObject.cpp

@@ -16,7 +16,28 @@
 #include "INISettingsObject.h"
 #include "Setting.h"
 
-INISettingsObject::INISettingsObject(const QString &path, QObject *parent)
+#include <QDebug>
+#include <QFile>
+
+INISettingsObject::INISettingsObject(QStringList paths, QObject *parent)
+    : SettingsObject(parent)
+{
+    auto first_path = paths.constFirst();
+    auto path = paths.takeFirst();
+    while (!QFile::exists(path))
+        path = paths.takeFirst();
+
+    if (path != first_path && QFile::exists(path)) {
+        // Copy the fallback to the preferred path.
+        QFile::copy(path, first_path);
+        qDebug() << "Copied settings from" << path << "to" << first_path;
+    }
+
+    m_filePath = first_path;
+    m_ini.loadFile(first_path);
+}
+
+INISettingsObject::INISettingsObject(QString path, QObject* parent)
     : SettingsObject(parent)
 {
     m_filePath = path;

launcher/settings/INISettingsObject.h

@@ -28,7 +28,10 @@ class INISettingsObject : public SettingsObject
 {
     Q_OBJECT
 public:
-    explicit INISettingsObject(const QString &path, QObject *parent = 0);
+    /** 'paths' is a list of INI files to try, in order, for fallback support. */
+    explicit INISettingsObject(QStringList paths, QObject* parent = nullptr);
+
+    explicit INISettingsObject(QString path, QObject*  parent = nullptr);
 
     /*!
      * \brief Gets the path to the INI file.