Fix things mentioned during code review

Ref: https://github.com/dolphin-emu/dolphin/pull/4917

Source/Core/Common/Config/Section.h

@@ -0,0 +1,110 @@
+// Copyright 2017 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <map>
+#include <string>
+#include <vector>
+
+// XXX: Purely for case insensitive compare
+#include "Common/CommonTypes.h"
+#include "Common/Config/Enums.h"
+#include "Common/IniFile.h"
+
+namespace Config
+{
+class Layer;
+class ConfigLayerLoader;
+
+using SectionValueMap = std::map<std::string, std::string, CaseInsensitiveStringCompare>;
+
+class Section
+{
+  friend Layer;
+  friend ConfigLayerLoader;
+
+public:
+  Section(LayerType layer, System system, const std::string& name);
+
+  virtual bool Exists(const std::string& key) const;
+  bool Delete(const std::string& key);
+
+  // Setters
+  virtual void Set(const std::string& key, const std::string& value);
+
+  void Set(const std::string& key, u32 newValue);
+  void Set(const std::string& key, float newValue);
+  void Set(const std::string& key, double newValue);
+  void Set(const std::string& key, int newValue);
+  void Set(const std::string& key, bool newValue);
+
+  // Setters with default values
+  void Set(const std::string& key, const std::string& newValue, const std::string& defaultValue);
+  template <typename T>
+  void Set(const std::string& key, T newValue, const T defaultValue)
+  {
+    if (newValue != defaultValue)
+      Set(key, newValue);
+    else
+      Delete(key);
+  }
+
+  // Getters
+  virtual bool Get(const std::string& key, std::string* value,
+                   const std::string& default_value = NULL_STRING) const;
+
+  bool Get(const std::string& key, int* value, int defaultValue = 0) const;
+  bool Get(const std::string& key, u32* value, u32 defaultValue = 0) const;
+  bool Get(const std::string& key, bool* value, bool defaultValue = false) const;
+  bool Get(const std::string& key, float* value, float defaultValue = 0.0f) const;
+  bool Get(const std::string& key, double* value, double defaultValue = 0.0) const;
+
+  template <typename T>
+  T Get(const std::string& key, const T& default_value) const
+  {
+    T value;
+    Get(key, value, default_value);
+    return value;
+  }
+
+  // Section chunk
+  void SetLines(const std::vector<std::string>& lines);
+  // XXX: Add to recursive layer
+  virtual bool GetLines(std::vector<std::string>* lines, const bool remove_comments = true) const;
+  virtual bool HasLines() const;
+  const std::string& GetName() const;
+  const SectionValueMap& GetValues() const;
+  const std::vector<std::string>& GetDeletedKeys() const;
+  bool IsDirty() const;
+  void ClearDirty();
+
+protected:
+  bool m_dirty = false;
+
+  LayerType m_layer;
+  System m_system;
+  const std::string m_name;
+  static const std::string& NULL_STRING;
+
+  SectionValueMap m_values;
+  std::vector<std::string> m_deleted_keys;
+
+  std::vector<std::string> m_lines;
+};
+
+// Only to be used with the meta-layer
+class RecursiveSection final : public Section
+{
+public:
+  RecursiveSection(LayerType layer, System system, const std::string& name);
+
+  bool Exists(const std::string& key) const override;
+
+  bool Get(const std::string& key, std::string* value,
+           const std::string& default_value = NULL_STRING) const override;
+
+  void Set(const std::string& key, const std::string& value) override;
+};
+}