Refactor folder item management and move NotifyValue to a new utility header

src/util/notify.h

@@ -0,0 +1,55 @@
+#ifndef YAZE_UTIL_NOTIFY_H
+#define YAZE_UTIL_NOTIFY_H
+
+namespace yaze {
+namespace util {
+
+/**
+ * @class NotifyValue
+ * @brief A class to manage a value that can be modified and notify when it
+ * changes.
+ */
+template <typename T>
+class NotifyValue {
+ public:
+  NotifyValue() : value_(), modified_(false), temp_value_() {}
+  NotifyValue(const T &value)
+      : value_(value), modified_(false), temp_value_() {}
+
+  void set(const T &value) {
+    value_ = value;
+    modified_ = true;
+  }
+
+  const T &get() {
+    modified_ = false;
+    return value_;
+  }
+
+  T &mutable_get() {
+    modified_ = false;
+    temp_value_ = value_;
+    return temp_value_;
+  }
+
+  void apply_changes() {
+    if (temp_value_ != value_) {
+      value_ = temp_value_;
+      modified_ = true;
+    }
+  }
+
+  void operator=(const T &value) { set(value); }
+  operator T() { return get(); }
+
+  bool modified() const { return modified_; }
+
+ private:
+  T value_;
+  bool modified_;
+  T temp_value_;
+};
+}  // namespace util
+}  // namespace yaze
+
+#endif