refactor: move file open event handling to standalone file

app/fileopeneventhandler.cpp

@@ -0,0 +1,22 @@
+// SPDX-FileCopyrightText: 2024 Gary Wang <git@blumia.net>
+//
+// SPDX-License-Identifier: MIT
+
+#include "fileopeneventhandler.h"
+
+#include <QFileOpenEvent>
+
+FileOpenEventHandler::FileOpenEventHandler(QObject *parent)
+    : QObject(parent)
+{
+}
+
+bool FileOpenEventHandler::eventFilter(QObject *obj, QEvent *event)
+{
+    if (event->type() == QEvent::FileOpen) {
+        QFileOpenEvent *fileOpenEvent = static_cast<QFileOpenEvent *>(event);
+        emit fileOpen(fileOpenEvent->url());
+        return true;
+    }
+    return QObject::eventFilter(obj, event);
+}