1 files changed, 169 insertions, 0 deletions
diff --git a/jsonobjectfilesingleton.h b/jsonobjectfilesingleton.h
new file mode 100644
index 0000000..f11b30a
--- /dev/null
+++ b/jsonobjectfilesingleton.h
@@ -0,0 +1,169 @@
+#pragma once
+
+// qt
+#include <QDebug>
+#include <QDir>
+#include <QFile>
+#include <QFileSystemWatcher>
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QMutex>
+#include <QSharedPointer>
+#include <QStandardPaths>
+#include <QVariant>
+
+#define JSON_OBJECT_FILE(classname) JsonObjectFile<classname>::get().data()
+
+template <class T> class JsonObjectFile
+{
+public:
+    static QSharedPointer<T> get()
+    {
+        static QMutex mtx;
+        QMutexLocker l(&mtx);
+
+        if (!m_instance)
+        {
+            m_instance = read();
+
+            qDebug() << "add filepath" << filepath();
+            if (!m_watcher.addPath(filepath()))
+            {
+                qt_noop();
+            }
+            qDebug() << m_watcher.directories() << m_watcher.files();
+
+            QObject::connect(
+                &m_watcher,
+                &QFileSystemWatcher::directoryChanged,
+                &m_watcher,
+                [&](const QString& path) {
+                    qDebug() << filepath() << "changed";
+                    if (path == filename())
+                    {
+                        qDebug() << "file changed:" << filename();
+                        *get() = *read();
+                    }
+                },
+                Qt::DirectConnection
+            );
+        }
+
+        return m_instance;
+    }
+
+    static QSharedPointer<T> read(const QString fileName = QString())
+    {
+        static QMutex mtx;
+        QMutexLocker l(&mtx);
+
+        if (!QDir(filepath()).exists())
+        {
+            QDir().mkpath(filepath());
+        }
+
+        QFile f(!fileName.isEmpty() ? fileName : filename());
+
+        if (!f.open(QFile::ReadOnly))
+        {
+            qDebug() << Q_FUNC_INFO << ":"
+                     << "cannot open file" << f.fileName() << ":\n"
+                     << f.errorString();
+
+            return QSharedPointer<T>();
+        }
+
+        auto data = f.readAll();
+        QJsonValue json = QJsonDocument::fromJson(data).object();
+        return QSharedPointer<T>(
+            new T(json[T::staticMetaObject.className()]),
+            &T::deleteLater
+        );
+    }
+
+    static bool write(
+        const QSharedPointer<T>& value,
+        const QString fileName = QString()
+    )
+    {
+        static QMutex mtx;
+        QMutexLocker l(&mtx);
+
+        QFile f(!fileName.isEmpty() ? fileName : filename());
+
+        if (!QDir(filepath()).exists())
+        {
+            QDir().mkpath(filepath());
+        }
+
+        //        bool fileExists = f.exists();
+
+        if (!f.open(QFile::WriteOnly))
+        {
+            qDebug() << Q_FUNC_INFO << ":"
+                     << "cannot open file" << f.fileName() << ":\n"
+                     << f.errorString();
+
+            return false;
+        }
+
+        const auto json =
+            QJsonObject{{T::staticMetaObject.className(), *value}};
+
+        f.write(QJsonDocument(json).toJson());
+        f.flush();
+
+        m_instance = read();
+
+        return true;
+    }
+
+    static bool remove(const QString fileName = QString())
+    {
+        static QMutex mtx;
+        QMutexLocker l(&mtx);
+
+        QFile f(!fileName.isEmpty() ? fileName : filename());
+
+        if (!f.remove())
+        {
+            qDebug() << Q_FUNC_INFO << ":"
+                     << "cannot delete file" << f.fileName() << ":\n"
+                     << f.errorString();
+
+            return false;
+        }
+
+        return true;
+    }
+
+    static QString filepath()
+    {
+        return QStandardPaths::writableLocation(
+            QStandardPaths::AppConfigLocation
+        );
+    }
+
+    static QString filename()
+    {
+        return filepath() + QDir::separator() +
+               T::staticMetaObject.className() + "." + extension;
+    }
+
+    typedef QSharedPointer<T> FactorySharedPointer;
+
+public:
+    static const QString extension;
+
+private:
+    static FactorySharedPointer m_instance;
+    static QFileSystemWatcher m_watcher;
+};
+
+template <typename T>
+QString const JsonObjectFile<T>::extension = QStringLiteral("json");
+
+template <class T>
+typename JsonObjectFile<T>::FactorySharedPointer JsonObjectFile<T>::m_instance;
+
+template <class T> QFileSystemWatcher JsonObjectFile<T>::m_watcher;