experimental/status-code/status_error.hpp

0001 /* Proposed SG14 status_code
0002 (C) 2018 - 2022 Niall Douglas <http://www.nedproductions.biz/> (5 commits)
0003 File Created: Feb 2018
0004
0005
0006 Licensed under the Apache License, Version 2.0 (the "License");
0007 you may not use this file except in compliance with the License.
0008 You may obtain a copy of the License in the accompanying file
0009 Licence.txt or at
0010
0011 http://www.apache.org/licenses/LICENSE-2.0
0012
0013 Unless required by applicable law or agreed to in writing, software
0014 distributed under the License is distributed on an "AS IS" BASIS,
0015 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0016 See the License for the specific language governing permissions and
0017 limitations under the License.
0018
0019
0020 Distributed under the Boost Software License, Version 1.0.
0021 (See accompanying file Licence.txt or copy at
0022 http://www.boost.org/LICENSE_1_0.txt)
0023 */
0024
0025 #ifndef BOOST_OUTCOME_SYSTEM_ERROR2_STATUS_ERROR_HPP
0026 #define BOOST_OUTCOME_SYSTEM_ERROR2_STATUS_ERROR_HPP
0027
0028 #include "status_code.hpp"
0029
0030 #include <exception>  // for std::exception
0031
0032 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_BEGIN
0033
0034 /*! Exception type representing a thrown status_code
0035  */
0036 template <class DomainType> class status_error;
0037
0038 /*! The erased type edition of status_error.
0039  */
0040 template <> class status_error<void> : public std::exception
0041 {
0042 protected:
0043   //! Constructs an instance. Not publicly available.
0044   status_error() = default;
0045   //! Copy constructor. Not publicly available
0046   status_error(const status_error &) = default;
0047   //! Move constructor. Not publicly available
0048   status_error(status_error &&) = default;
0049   //! Copy assignment. Not publicly available
0050   status_error &operator=(const status_error &) = default;
0051   //! Move assignment. Not publicly available
0052   status_error &operator=(status_error &&) = default;
0053   //! Destructor. Not publicly available.
0054   ~status_error() override = default;
0055
0056   virtual const status_code<void> &_do_code() const noexcept = 0;
0057
0058 public:
0059   //! The type of the status domain
0060   using domain_type = void;
0061   //! The type of the status code
0062   using status_code_type = status_code<void>;
0063
0064 public:
0065   //! The erased status code which generated this exception instance.
0066   const status_code<void> &code() const noexcept { return _do_code(); }
0067 };
0068
0069 /*! Exception type representing a thrown status_code
0070  */
0071 template <class DomainType> class status_error : public status_error<void>
0072 {
0073   status_code<DomainType> _code;
0074   typename DomainType::string_ref _msgref;
0075
0076   virtual const status_code<void> &_do_code() const noexcept override final { return _code; }
0077
0078 public:
0079   //! The type of the status domain
0080   using domain_type = DomainType;
0081   //! The type of the status code
0082   using status_code_type = status_code<DomainType>;
0083
0084   //! Constructs an instance
0085   explicit status_error(status_code<DomainType> code)
0086       : _code(static_cast<status_code<DomainType> &&>(code))
0087       , _msgref(_code.message())
0088   {
0089   }
0090
0091   //! Return an explanatory string
0092   virtual const char *what() const noexcept override { return _msgref.c_str(); }  // NOLINT
0093
0094   //! Returns a reference to the code
0095   const status_code_type &code() const & { return _code; }
0096   //! Returns a reference to the code
0097   status_code_type &code() & { return _code; }
0098   //! Returns a reference to the code
0099   const status_code_type &&code() const && { return _code; }
0100   //! Returns a reference to the code
0101   status_code_type &&code() && { return _code; }
0102 };
0103
0104 /*! Exception type representing a thrown erased status_code
0105  */
0106 template <class ErasedType> class status_error<detail::erased<ErasedType>> : public status_error<void>
0107 {
0108   status_code<detail::erased<ErasedType>> _code;
0109   typename status_code_domain::string_ref _msgref;
0110
0111   virtual const status_code<detail::erased<ErasedType>> &_do_code() const noexcept override final { return _code; }
0112
0113 public:
0114   //! The type of the status domain
0115   using domain_type = void;
0116   //! The type of the status code
0117   using status_code_type = status_code<detail::erased<ErasedType>>;
0118
0119   //! Constructs an instance
0120   explicit status_error(status_code<detail::erased<ErasedType>> code)
0121       : _code(static_cast<status_code<detail::erased<ErasedType>> &&>(code))
0122       , _msgref(_code.message())
0123   {
0124   }
0125
0126   //! Return an explanatory string
0127   virtual const char *what() const noexcept override { return _msgref.c_str(); }  // NOLINT
0128
0129   //! Returns a reference to the code
0130   const status_code_type &code() const & { return _code; }
0131   //! Returns a reference to the code
0132   status_code_type &code() & { return _code; }
0133   //! Returns a reference to the code
0134   const status_code_type &&code() const && { return _code; }
0135   //! Returns a reference to the code
0136   status_code_type &&code() && { return _code; }
0137 };
0138
0139 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_END
0140
0141 #endif