Merged emitter branch into trunk, changes r105:r151

src/setting.h

@@ -0,0 +1,97 @@
+#pragma once
+
+#include <memory>
+#include <vector>
+#include "noncopyable.h"
+
+namespace YAML
+{
+	class SettingChangeBase;
+	
+	template <typename T>
+	class Setting
+	{
+	public:
+		Setting(): m_value() {}
+		
+		const T get() const { return m_value; }
+		std::auto_ptr <SettingChangeBase> set(const T& value);
+		void restore(const Setting<T>& oldSetting) {
+			m_value = oldSetting.get();
+		}
+		
+	private:
+		T m_value;
+	};
+
+	class SettingChangeBase
+	{
+	public:
+		virtual ~SettingChangeBase() {}
+		virtual void pop() = 0;
+	};
+	
+	template <typename T>
+	class SettingChange: public SettingChangeBase
+	{
+	public:
+		SettingChange(Setting<T> *pSetting): m_pCurSetting(pSetting) {
+			// copy old setting to save its state
+			m_oldSetting = *pSetting;
+		}
+		
+		virtual void pop() {
+			m_pCurSetting->restore(m_oldSetting);
+		}
+
+	private:
+		Setting<T> *m_pCurSetting;
+		Setting<T> m_oldSetting;
+	};
+
+	template <typename T>
+	inline std::auto_ptr <SettingChangeBase> Setting<T>::set(const T& value) {
+		std::auto_ptr <SettingChangeBase> pChange(new SettingChange<T> (this));
+		m_value = value;
+		return pChange;
+	}
+	
+	class SettingChanges: private noncopyable
+	{
+	public:
+		SettingChanges() {}
+		~SettingChanges() { clear(); }
+		
+		void clear() {
+			restore();
+			
+			for(setting_changes::const_iterator it=m_settingChanges.begin();it!=m_settingChanges.end();++it)
+				delete *it;
+			m_settingChanges.clear();
+		}
+		
+		void restore() {
+			for(setting_changes::const_iterator it=m_settingChanges.begin();it!=m_settingChanges.end();++it)
+				(*it)->pop();
+		}
+		
+		void push(std::auto_ptr <SettingChangeBase> pSettingChange) {
+			m_settingChanges.push_back(pSettingChange.release());
+		}
+		
+		// like std::auto_ptr - assignment is transfer of ownership
+		SettingChanges& operator = (SettingChanges& rhs) {
+			if(this == &rhs)
+				return *this;
+			
+			clear();
+			m_settingChanges = rhs.m_settingChanges;
+			rhs.m_settingChanges.clear();
+			return *this;
+		}
+		
+	private:
+		typedef std::vector <SettingChangeBase *> setting_changes;
+		setting_changes m_settingChanges;
+	};
+}