Exception.h

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/***************************************************************************
 *
 * Copyright (C) 2009-2010 Cassio Neri Moreira
 *
 * This file is part of the KeyValue library.
 *
 * The KeyValue library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 *
 * The KeyValue library 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 General
 * Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with KeyValue. If not, see <http://www.gnu.org/licenses/>.
 *
 **************************************************************************/

#ifndef KEYVALUE_SYS_EXCEPTION_EXCEPTION_H_
#define KEYVALUE_SYS_EXCEPTION_EXCEPTION_H_

#include <iosfwd>
#include <stdexcept>

#include "keyvalue/sys/message/MessageImpl.h"

namespace keyvalue {

namespace exception {

class Exception {

public:

  Exception();

  virtual
  ~Exception() throw();

  virtual const char*
  what() const = 0;

  virtual const Message&
  getMessage() const = 0;

}; // class Exception

std::ostream&
operator<<(std::ostream& os, const Exception& exception);

template<typename StdExcept, typename MessageType>
class ExceptionImpl: public Exception, public StdExcept {

public:

  ExceptionImpl();

  virtual
  ~ExceptionImpl() throw();

  const Message&
  getMessage() const;

  const char*
  what() const throw();

  template<typename DataType>
  ExceptionImpl&
  operator&(const DataType& data);

private:

  MessageType message_;
  mutable string str_;

}; // class ExceptionImpl

template <typename LhsType, typename RhsType>
LhsType&
operator&(const LhsType& lhs, const RhsType& rhs) {
  LhsType& mutableLhs(const_cast<LhsType&>(lhs));
  mutableLhs.operator&(rhs);
  return mutableLhs;
}

typedef ExceptionImpl<std::runtime_error, Error> RuntimeError;

typedef ExceptionImpl<std::logic_error, Logic> LogicError;

/*--------------------------------------------------------------------------
 * ExceptionImpl::ExceptionImpl()
 *------------------------------------------------------------------------*/

template <typename StdExcept, typename MessageType>
ExceptionImpl<StdExcept, MessageType>::ExceptionImpl() : StdExcept("") {
}

/*--------------------------------------------------------------------------
 * ExceptionImpl::~ExceptionImpl()
 *------------------------------------------------------------------------*/

template <typename StdExcept, typename MessageType>
ExceptionImpl<StdExcept, MessageType>::~ExceptionImpl() throw() {
}

/*--------------------------------------------------------------------------
 * ExceptionImpl::getMessage()
 *------------------------------------------------------------------------*/

template <typename StdExcept, typename MessageType>
const Message&
ExceptionImpl<StdExcept, MessageType>::getMessage() const {
  return message_;
}

/*--------------------------------------------------------------------------
 * ExceptionImpl::what()
 *------------------------------------------------------------------------*/

template <typename StdExcept, typename MessageType>
const char*
ExceptionImpl<StdExcept, MessageType>::what() const throw() {
  message_.getString().swap(str_);
  return str_.c_str();
}

/*--------------------------------------------------------------------------
 * ExceptionImpl::operator&()
 *------------------------------------------------------------------------*/

template<typename StdExcept, typename MessageType>
template<typename DataType>
ExceptionImpl<StdExcept, MessageType>&
ExceptionImpl<StdExcept, MessageType>::operator&(const DataType& data) {
  message_ & data;
  return *this;
}

} // namespace exception

using exception::Exception;
using exception::RuntimeError;
using exception::LogicError;

} // namespace keyvalue

#endif // KEYVALUE_SYS_EXCEPTION_EXCEPTION_H_