// <system_error> -*- C++ -*-

// Copyright (C) 2007, 2008 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This 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 2, or (at your option)
// any later version.

// This 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 this library; see the file COPYING.  If not, write to
// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301, USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/** @file system_error
 *  This is a Standard C++ Library header.
 */

#ifndef _GLIBCXX_SYSTEM_ERROR
#define _GLIBCXX_SYSTEM_ERROR 1

#pragma GCC system_header

#ifndef __GXX_EXPERIMENTAL_CXX0X__
# include <c++0x_warning.h>
#endif

#include <bits/c++config.h>
#include <bits/error_constants.h>
#include <iosfwd>
#include <stdexcept>

_GLIBCXX_BEGIN_NAMESPACE(std)

  class error_code;
  class error_condition;
  class error_category;
  class system_error;

  /// is_error_code_enum
  template<typename _T>
    struct is_error_code_enum : public false_type { };

  template<> 
    struct is_error_code_enum<posix_error::posix_errno>
    : public true_type { };

  /// is_error_condition_enum
  template<typename _T>
    struct is_error_condition_enum : public false_type { };

  template<> 
    struct is_error_condition_enum<posix_error::posix_errno>
    : public true_type { };


  /// error_category
  struct error_category
  {
    error_category() { }

    virtual const char* 
    name() const = 0;

    virtual string 
    message(int) const = 0;

    virtual error_condition
    default_error_condition(int __i) const;

    virtual bool 
    equivalent(int __i, const error_condition& __cond) const;

    virtual bool 
    equivalent(const error_code& __code, int __i) const;

    bool 
    operator<(const error_category& __other) const
    { return less<const error_category*>()(this, &__other); }

    bool 
    operator==(const error_category& __other) const
    { return this == &__other; }

    bool 
    operator!=(const error_category& __other) const
    { return this != &__other; }

  private:
    error_category(const error_category&);

    error_category& 
    operator=(const error_category&);
  };

  const error_category& get_posix_category();
  const error_category& get_system_category();

  static const error_category& system_category = get_system_category();
  static const error_category& native_category = get_posix_category();

  /// error_code
  // Implementation-specific error identification
  struct error_code
  {
    error_code()
    : _M_value(0), _M_cat(&system_category) { }

    error_code(int __v, const error_category& __cat)
    : _M_value(__v), _M_cat(&__cat) { }

    template<typename _ErrorCodeEnum>
      error_code(_ErrorCodeEnum __e,
      typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type* = 0)
      : _M_value(__e), _M_cat(&system_category)
      { }

    void 
    assign(int __v, const error_category& __cat)
    {
      _M_value = __v;
      _M_cat = &__cat; 
    }

    void 
    clear()
    { 
      _M_value = 0;
      _M_cat = &system_category;
    } 

    template<typename _ErrorCodeEnum>
      typename enable_if<is_error_code_enum<_ErrorCodeEnum>::value>::type&
      operator=(_ErrorCodeEnum __e)
      { _M_value = __e; }

    int
    value() const { return _M_value; }
      
    const error_category&  
    category() const { return *_M_cat; }

    error_condition 
    default_error_condition() const;

    string 
    message() const
    { return category().message(value()); }

    // Safe bool idiom.
    // explicit operator bool() const throw()
    // { return _M_value != 0; }
    typedef void (*__bool_type)();

    static void __not_bool_type() { }

    operator __bool_type() const
    { return _M_value != 0 ? &__not_bool_type : false; }

  private:
    int            		_M_value;
    const error_category* 	_M_cat;
  };

  error_code 
  make_error_code(posix_error::posix_errno);

  // 19.4.2.5 non-member functions
  bool operator<(const error_code& lhs, const error_code& rhs);

  template<typename charT, typename traits>
    basic_ostream<charT,traits>&
    operator<<(basic_ostream<charT,traits>& os, const error_code& __code);


  /// error_condition
  // Portable error identification
  struct error_condition 
  {
    error_condition() : _M_value(0), _M_cat(system_category) { }

    error_condition(int __v, const error_category& __cat)     
    : _M_value(__v), _M_cat(__cat) { }

    template<typename _ErrorEnum>
      error_condition(typename enable_if<is_error_condition_enum<_ErrorEnum>::value, _ErrorEnum>::type __v) : _M_value(__v), _M_cat(system_category) { }

    void 
    assign(int val, const error_category& cat);

    template<typename _ErrorEnum>
      error_condition&
      operator=(typename enable_if<is_error_condition_enum<_ErrorEnum>::value, _ErrorEnum>::type __v)
      { _M_value = __v; }

    void 
    clear();

    // 19.4.3.4 observers
    int 
    value() const { return _M_value; }

    const error_category& 
    category() const { return _M_cat; }

    string 
    message() const
    { return category().message(value()); }

    // Safe bool idiom.
    // explicit operator bool() const throw()
    // { return _M_value != 0; }
    typedef void (*__bool_type)();

    static void __not_bool_type() { }

    operator __bool_type() const
    { return _M_value != 0 ? &__not_bool_type : false; }

  private:
    int 			_M_value;
    const error_category& 	_M_cat;
  };

  error_condition 
  make_error_condition(posix_error::posix_errno);

  // 19.4.3.5 non-member functions
  inline bool 
  operator<(const error_condition& lhs, const error_condition& rhs)
  { 
    bool __t1 = lhs.category() < rhs.category();
    bool __t2 = lhs.category() == rhs.category() && lhs.value() < rhs.value();
    return __t1 || __t2;
  }

  // 19.4.4 Comparison operators
  inline bool 
  operator==(const error_code& lhs, const error_code& rhs)
  { return lhs.category() == rhs.category() && lhs.value() == rhs.value(); }

  inline bool 
  operator==(const error_code& lhs, const error_condition& rhs)
  {
    bool __t1 = lhs.category().equivalent(lhs.value(), rhs);
    bool __t2 = rhs.category().equivalent(lhs, rhs.value());
    return __t1 || __t2;
  }

  inline bool 
  operator==(const error_condition& lhs, const error_code& rhs)
  {
    bool __t1 = rhs.category().equivalent(rhs.value(), lhs);
    bool __t2 = lhs.category().equivalent(rhs, lhs.value());
    return __t1 || __t2;
  }

  inline bool 
  operator==(const error_condition& lhs, const error_condition& rhs)
  { return lhs.category() == rhs.category() && lhs.value() == rhs.value(); }

  inline bool 
  operator!=(const error_code& lhs, const error_code& rhs)
  { return !(lhs == rhs); }

  inline bool 
  operator!=(const error_code& lhs, const error_condition& rhs)
  { return !(lhs == rhs); }

  inline bool 
  operator!=(const error_condition& lhs, const error_code& rhs)
  { return !(lhs == rhs); }

  inline bool 
  operator!=(const error_condition& lhs, const error_condition& rhs)
  { return !(lhs == rhs); }

  /// Thrown to indicate error code of underlying system.
  class system_error : public std::runtime_error
  {
  private:
    error_code 	_M_code;

  public:
    system_error(error_code __ec = error_code())
    : runtime_error(""), _M_code(__ec) { }

    system_error(error_code __ec, const string& __what)
    : runtime_error(__what), _M_code(__ec) { }

    system_error(int __v, const error_category& __ecat)
    : runtime_error(""), _M_code(error_code(__v, __ecat)) { }

    system_error(int __v, const error_category& __ecat, const string& __what)
    : runtime_error(__what), _M_code(error_code(__v, __ecat)) { }

    virtual ~system_error() throw();

    const error_code& 
    code() const throw() { return _M_code; }
  };

_GLIBCXX_END_NAMESPACE

#endif