DatabaseTransaction.h

Go to the documentation of this file.

/*
 * Copyright 2006-2009 Savarese Software Research Corporation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.savarese.com/software/ApacheLicense-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef __SSRC_WSPR_DATABASE_DATABASE_TRANSACTION_H
#define __SSRC_WSPR_DATABASE_DATABASE_TRANSACTION_H

#include <ssrc/wispers/database/Database.h>

#include <boost/noncopyable.hpp>

__BEGIN_NS_SSRC_WSPR_DATABASE

// This is a convenience macro intended only for internal use by the
// library and is therefore left undocumented.
#define WSPR_DB_INIT_QUERY(key) \
    _ ## key(_database.prepare(*properties.get_ptr<string>(#key)))

class DatabaseWrapper {
protected:
  friend class DatabaseTransaction;
  Database _database;

public:

  explicit DatabaseWrapper(const string & db_file) SSRC_DECL_THROW(DatabaseException) :
    _database(db_file)
  { }

  virtual ~DatabaseWrapper() { }

  void begin_transaction() SSRC_DECL_THROW(DatabaseException) {
    _database.begin_transaction();
  }

  void rollback_transaction() SSRC_DECL_THROW(DatabaseException) {
    _database.rollback_transaction();
  }

  void end_transaction() SSRC_DECL_THROW(DatabaseException) {
    _database.end_transaction();
  }
};


class DatabaseTransaction : private boost::noncopyable {
  enum State { Undefined, Begin, End };
  State _state;
  Database & _db;
  
public:

  DatabaseTransaction(DatabaseWrapper & dbw)
    SSRC_DECL_THROW(DatabaseException) :
    _state(Undefined), _db(dbw._database)
  {
    _db.begin_transaction();
    _state = Begin;
  }

  DatabaseTransaction(Database & db) SSRC_DECL_THROW(DatabaseException) :
    _state(Undefined), _db(db)
  {
    _db.begin_transaction();
    _state = Begin;
  }

  void end() SSRC_DECL_THROW(DatabaseException) {
    if(_state == Begin) {
      _db.end_transaction();
      _state = End;
    }
  }

  void rollback() SSRC_DECL_THROW(DatabaseException) {
    if(_state == Begin) {
      _state = Undefined;
      _db.rollback_transaction();
    }
  }

  ~DatabaseTransaction() {
    try {
      rollback();
    } catch(const DatabaseException & de) {
      // TODO: add some kind of error reporting
    }
  }
};

__END_NS_SSRC_WSPR_DATABASE

#endif