system_error.h

//
//  Copyright (C) 2009-2012 Artyom Beilis (Tonkikh)
//
//  Distributed under the Boost Software License, Version 1.0. (See
//  accompanying file LICENSE_1_0.txt or copy at
//  http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef BOOSTER_SYSTEM_ERROR_H
#define BOOSTER_SYSTEM_ERROR_H

#include <string>
#include <booster/backtrace.h>
#include <functional>

#include <booster/config.h>

namespace booster {

namespace system {

        class error_category {
        public:
                virtual ~error_category()
                {
                }
                virtual char const *name() const = 0;
                virtual std::string message(int ev) const = 0;

                bool operator==(error_category const &other) const
                {
                        return this==&other;
                }
                bool operator!=(error_category const &other) const
                {
                        return this!=&other;
                }
                bool operator<(error_category const &other) const
                {
                        return std::less<error_category const *>()(this,&other);
                }

        };

        BOOSTER_API error_category const &get_system_category();
        BOOSTER_UNUSED static const error_category &system_category = get_system_category();
        
        #ifdef BOOSTER_WIN32
        BOOSTER_API error_category const &get_windows_category();
        BOOSTER_UNUSED static const error_category &windows_category = get_system_category();
        #endif

        #ifdef BOOSTER_POSIX
        BOOSTER_API error_category const &get_posix_category();
        BOOSTER_UNUSED static const error_category &posix_category = get_system_category();
        #endif


        class error_code {
        public:
                error_code() : 
                        value_(0),
                        category_(&system_category)
                {
                }
                error_code(int val,error_category const &cat) :
                        value_(val),
                        category_(&cat)
                {
                }
                int value() const
                {
                        return value_;
                }
                const error_category &category() const
                {
                        return *category_;
                }
                std::string message() const
                {
                        return std::string(category_->name()) + ": " + category_->message(value_);
                }
                operator bool () const
                {
                        return value() != 0;
                }
        private:
                int value_;
                error_category const *category_;
        };

        inline bool operator==(error_code const &left,error_code const &right)
        {
                return left.value() == right.value() && left.category() == right.category(); 
        }
        inline bool operator!=(error_code const &left,error_code const &right)
        {
                return !(left==right);
        }

        class system_error : public booster::runtime_error {
        public:
                system_error(error_code const &e) :
                        booster::runtime_error(e.message()),
                        error_(e)
                {
                }
                system_error(error_code const &e,std::string const &message) :
                        booster::runtime_error(e.message()+": " + message),
                        error_(e)
                {
                }
                system_error(error_code const &e,char const *message) :
                        booster::runtime_error(e.message()+": " + message),
                        error_(e)
                {
                }
                system_error(int ev,error_category const &category,char const *message) :
                        booster::runtime_error(
                                std::string(category.name()) 
                                + ": "  + category.message(ev) 
                                + ": "  + message
                                ),
                        error_(ev,category)
                {
                }
                system_error(int ev,error_category const &category,std::string const &message) :
                        booster::runtime_error(
                                std::string(category.name()) 
                                + ": "  + category.message(ev) 
                                + ": "  + message
                                ),
                        error_(ev,category)
                {
                }
                system_error(int ev,error_category const &category) :
                        booster::runtime_error(
                                std::string(category.name()) 
                                + ": "  + category.message(ev) 
                                ),
                        error_(ev,category)
                {
                }
                error_code const &code() const
                {
                        return error_;
                }
        private:
                error_code error_;
        };

} // system
} // booster


#endif