/sqlite3cc

/*

 * transaction.h

 *

 * Copyright (C) 2009 Tim Marston <tim@ed.am>

 *

 * This file is part of sqlite3cc (hereafter referred to as "this program").

 * See http://ed.am/dev/sqlite3cc for more information.

 *

 * This program is free software: you can redistribute it and/or modify it under

 * the terms of the GNU Lesser General Public License as published by the Free

 * Software Foundation, either version 3 of the License, or (at your option) any

 * later version.

 *

 * This program is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

 * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

 * details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

#ifndef SQLITE3CC_TRANSACTION_H_

#define SQLITE3CC_TRANSACTION_H_

#include <boost/utility.hpp>

#include <string>

namespace sqlite

{

class connection;

namespace detail

{

	/**

	 * A basic (default, deferred) transaction.

	 */

	class basic_transaction

		:

		private boost::noncopyable

	{

	//__________________________________________________________________________

	//                                                             instantiation

	public:

		/**

		 * Constructor that provides a connection upon which to act.

		 *

		 * @param connection a connection

		 */

		explicit basic_transaction(

			connection &connection );

	//__________________________________________________________________________

	//                                                          public interface

	public:

		/**

		 * Begin the transaction

		 */

		virtual void begin();

		/**

		 * Commit the transaction

		 */

		virtual void commit();

		/**

		 * Rollback the transaction

		 */

		virtual void rollback();

	//__________________________________________________________________________

	//                                                            implementation

	protected:

		/** reset any in-progress statements */

		void reset_active_queries();

		/** the connection on which to act */

		connection &_connection;

	};

} // namespace detail

////////////////////////////////////////////////////////////////////////////////

/**

 * A deferred transaction.

 */

typedef detail::basic_transaction deferred_transaction;

////////////////////////////////////////////////////////////////////////////////

/**

 * An immediate transaction.

 */

class immediate_transaction

	:

	public detail::basic_transaction

{

//______________________________________________________________________________

//                                                                 instantiation

public:

	/**

	 * Constructor that provides a connection upon which to act.

	 *

	 * @param connection a connection

	 */

	explicit immediate_transaction(

		connection &connection );

//______________________________________________________________________________

//                                                              public interface

public:

	/**

	 * Begin the transaction.

	 */

	virtual void begin();

};

////////////////////////////////////////////////////////////////////////////////

/**

 * An exclusive transaction.

 */

class exclusive_transaction

	:

	public detail::basic_transaction

{

//______________________________________________________________________________

//                                                                 instantiation

public:

	/**

	 * Constructor that provides a connection upon which to act.

	 *

	 * @param connection a connection

	 */

	explicit exclusive_transaction(

		connection &connection );

//______________________________________________________________________________

//                                                              public interface

public:

	/**

	 * Begin the transaction

	 */

	virtual void begin();

};

////////////////////////////////////////////////////////////////////////////////

/**

 * A recursive transaction, allowing transactions to be nested.

 */

class recursive_transaction

	:

	public detail::basic_transaction

{

//______________________________________________________________________________

//                                                                 instantiation

public:

	/**

	 * Constructor that provides a connection upon which to act.

	 *

	 * @param connection a connection

	 */

	explicit recursive_transaction(

		connection &connection );

//______________________________________________________________________________

//                                                              public interface

public:

	/**

	 * Begin the transaction.

	 */

	virtual void begin();

	/**

	 * Commit the transaction.

	 */

	virtual void commit();

	/**

	 * Rollback the transaction.

	 */

	virtual void rollback();

//______________________________________________________________________________

//                                                                implementation

protected:

	/* this transaction's savepoint name */

	std::string _sp_name;

};

////////////////////////////////////////////////////////////////////////////////

/**

 * A scope guard (sentinel) for use with one of the transaction classes to

 * provide RAII-style transactions.  It defaults to using deferred transactions.

 */

template< class T = deferred_transaction >

class transaction_guard

	:

	private boost::noncopyable

{

//______________________________________________________________________________

//                                                                 instantiation

public:

	/**

	 * Constructor that provides a connection upon which to act.

	 *

	 * @param connection a connection

	 */

	explicit transaction_guard(

		connection &connection )

		:

		_transaction( connection ),

		_released( true )

	{

		_transaction.begin();

		_released = false;

	}

	~transaction_guard()

	{

		if( !_released )

			_transaction.rollback();

	}

//______________________________________________________________________________

//                                                              public interface

public:

	/**

	 * Begin the transaction. Note that this is done automatically in the

	 * constructor.

	 */

	void begin()

	{

		if( _released ) {

			_transaction.begin();

			_released = false;

		}

	}

	/**

	 * Commit the transaction.

	 */

	void commit()

	{

		if( !_released ) {

			_transaction.commit();

			_released = true;

		}

	}

	/**

	 * Rollback the transaction. Note that this is done automatically in the

	 * destructor if the transaction hasn't otherwise been completed.

	 */

	void rollback()

	{

		if( !_released ) {

			_transaction.rollback();

			_released = true;

		}

	}

//______________________________________________________________________________

//                                                                implementation

protected:

	/** the transaction */

	T _transaction;

	/** have we released the transaction yet? */

	bool _released;

};

} // namespace sqlite

#endif /* SQLITE3CC_TRANSACTION_H_ */