anope/include/serialize.h

/*
 *
 * (C) 2003-2012 Anope Team
 * Contact us at team@anope.org
 *
 * Please read COPYING and README for further details.
 *
 * Based on the original code of Epona by Lara.
 * Based on the original code of Services by Andy Church.
 *
 */

#ifndef SERIALIZE_H
#define SERIALIZE_H

#include <sstream>

#include "anope.h"
#include "base.h"

namespace Serialize
{
 	enum DataType
	{
		DT_TEXT,
		DT_INT
	};

	class CoreExport stringstream : public std::stringstream
	{
	 private:
		Serialize::DataType type;
		unsigned _max;

	 public:
		stringstream();
		stringstream(const stringstream &ss);
		Anope::string astr() const;

		template<typename T> std::istream &operator>>(T &val)
		{
			std::istringstream is(this->str());
			is >> val;
			return *this;
		}
		std::istream &operator>>(Anope::string &val);

		bool operator==(const stringstream &other) const;
		bool operator!=(const stringstream &other) const;

		stringstream &SetType(Serialize::DataType t);
		Serialize::DataType GetType() const;
		stringstream &SetMax(unsigned m);
		unsigned GetMax() const;
	};

	typedef std::map<Anope::string, stringstream> Data;

	extern void RegisterTypes();

	class Type;
	template<typename T> class Checker;
	template<typename T> class Reference;
}

/** A serialziable object. Serializable objects can be serialized into
 * a map of stringstreams (Serialize::Data), and then reconstructed or
 * updated later at any time.
 */
class CoreExport Serializable : public virtual Base
{
 private:
	/* A list of every serializable item in Anope.
	 * Some of these are static and constructed at runtime,
	 * so this list must be on the heap, as it is not always
	 * constructed before other objects are if it isn't.
	 */
	static std::list<Serializable *> *SerializableItems;
	/* The type of item this object is */
	Serialize::Type *s_type;
 private:
 	/* Iterator into serializable_items */
	std::list<Serializable *>::iterator s_iter;
	/* The last serialized form of this object commited to the database */
	Serialize::Data last_commit;
	/* The last time this object was commited to the database */
	time_t last_commit_time;

	Serializable();
 protected:
 	Serializable(const Anope::string &serialize_type);
	Serializable(const Serializable &);

	virtual ~Serializable();

	Serializable &operator=(const Serializable &);

 public:
 	/* Unique ID (per type, not globally) for this object */
	unsigned int id;

	/* Destroys this object. This is effectively the same thing as
	 * delete, however it properly cleans up after this object.
	 */
	void Destroy();

	/** Marks the object as potentially being updated "soon".
	 */
	void QueueUpdate();

	bool IsCached();
	void UpdateCache();

	bool IsTSCached();
	void UpdateTS();

	/** Get the type of serializable object this is
	 * @return The serializable object type
	 */
	Serialize::Type* GetSerializableType() const;

	virtual Serialize::Data Serialize() const = 0;

	static const std::list<Serializable *> &GetItems();
};

/* A serializable type. There should be one of these classes for each type
 * of class that inherits from Serialiable. Used for unserializing objects
 * of this type, as it requires a function pointer to a static member function.
 */
class CoreExport Serialize::Type
{
	typedef Serializable* (*unserialize_func)(Serializable *obj, Serialize::Data &);

	static std::vector<Anope::string> TypeOrder;
	static std::map<Anope::string, Serialize::Type *> Types;

	/* The name of this type, should be a class name */
	Anope::string name;
	unserialize_func unserialize;
	/* Owner of this type. Used for placing objects of this type in separate databases
	 * based on what module, if any, owns it.
	 */
	Module *owner;

	/* The timesatmp for this type. All objects of this type are as up to date as
	 * this timestamp. if curtime == timestamp then we have the most up to date
	 * version of every object of this type.
	 */
	time_t timestamp;

 public:
 	/* Map of Serializable::id to Serializable objects */
	std::map<unsigned int, Serializable *> objects;

	/** Creates a new serializable type
	 * @param n Type name
	 * @param f Func to unserialize objects
	 * @param owner Owner of this type. Leave NULL for the core.
	 */
	Type(const Anope::string &n, unserialize_func f, Module *owner = NULL);
	~Type();

	/** Gets the name for this type
	 * @return The name, eg "NickAlias"
	 */
	const Anope::string &GetName();

	/** Unserialized an object.
	 * @param obj NULL if this object doesn't yet exist. If this isn't NULL, instead
	 * update the contents of this object.
	 * @param data The data to unserialize
	 * @return The unserialized object. If obj != NULL this should be obj.
	 */
	Serializable *Unserialize(Serializable *obj, Serialize::Data &data);

	/** Check if this object type has any pending changes and update them.
	 */
	void Check();

	/** Gets the timestamp for the object type. That is, the time we know
	 * all objects of this type are updated at least to.
	 */
	time_t GetTimestamp() const;

	/** Bumps object type timestamp to current time
	 */
	void UpdateTimestamp();

	Module* GetOwner() const;

	static Serialize::Type *Find(const Anope::string &name);

	static const std::vector<Anope::string> &GetTypeOrder();
};

/** Should be used to hold lists and other objects of a specific type,
 * but not a specific object. Used for ensuring that any access to
 * this object type is always up to date. These are usually constructed
 * at run time, before main is called, so no types are registered. This
 * is why there are static Serialize::Type* variables in every function.
 */
template<typename T>
class Serialize::Checker
{
	Anope::string name;
	T obj;

 public:
	Checker(const Anope::string &n) : name(n) { }

	inline const T* operator->() const
	{
		static Serialize::Type *type = Serialize::Type::Find(this->name);
		if (type)
			type->Check();
		return &this->obj;
	}
	inline T* operator->()
	{
		static Serialize::Type *type = Serialize::Type::Find(this->name);
		if (type)
			type->Check();
		return &this->obj;
	}

	inline const T& operator*() const
	{
		static Serialize::Type *type = Serialize::Type::Find(this->name);
		if (type)
			type->Check();
		return this->obj;
	}
	inline T& operator*()
	{
		static Serialize::Type *type = Serialize::Type::Find(this->name);
		if (type)
			type->Check();
		return this->obj;
	}

	inline operator const T&() const
	{
		static Serialize::Type *type = Serialize::Type::Find(this->name);
		if (type)
			type->Check();
		return this->obj;
	}
	inline operator T&()
	{
		static Serialize::Type *type = Serialize::Type::Find(this->name);
		if (type)
			type->Check();
		return this->obj;
	}
};

/** Used to hold references to serializable objects. Reference should always be
 * used when holding references to serializable objects for extended periods of time
 * to ensure that the object it refers to it always up to date. This also behaves like
 * Reference in that it will invalidate itself if the object it refers to is
 * destructed.
 */
template<typename T>
class Serialize::Reference : public ReferenceBase
{
 protected:
	T *ref;

 public:
 	Reference() : ref(NULL)
	{
	}

	Reference(T *obj) : ref(obj)
	{
		if (obj)
			obj->AddReference(this);
	}

	Reference(const Reference<T> &other) : ref(other.ref)
	{
		if (*this)
			this->ref->AddReference(this);
	}

	~Reference()
	{
		if (*this)
			this->ref->DelReference(this);
	}

	inline operator bool() const
	{
		if (!this->invalid)
			return this->ref != NULL;
		return false;
	}

	inline void operator=(T *newref)
	{
		if (*this)
			this->ref->DelReference(this);

		this->ref = newref;
		this->invalid = false;

		if (newref)
			this->ref->AddReference(this);
	}

	inline operator T*() const
	{
		if (!this->invalid)
		{
			if (this->ref)
				this->ref->QueueUpdate();
			return this->ref;
		}
		return NULL;
	}

	inline T* operator*() const
	{
		if (!this->invalid)
		{
			if (this->ref)
				this->ref->QueueUpdate();
			return this->ref;
		}
		return NULL;
	}

	inline T* operator->() const
	{
		if (!this->invalid)
		{
			if (this->ref)
				this->ref->QueueUpdate();
			return this->ref;
		}
		return NULL;
	}
};

#endif // SERIALIZE_H