asio_error.h

/*
* TLS Stream Errors
* (C) 2018-2020 Jack Lloyd
*     2018-2020 Hannes Rantzsch, Tim Oesterreich, Rene Meusel
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_ASIO_ERROR_H_
#define BOTAN_ASIO_ERROR_H_

#include <botan/build.h>

#include <boost/version.hpp>
#if BOOST_VERSION >= 106600

#include <boost/system/system_error.hpp>

#include <botan/exceptn.h>
#include <botan/tls_alert.h>
#include <botan/tls_exceptn.h>

/*
 * This file defines Botan-specific subclasses of boost::system::error_category.
 * In addition to the class definition, each category class is accompanied by function `make_error_code` used to create
 * a `boost::system::error_code` of the category from some other kind of error in Botan (for example, a TLS alert).
 * Since error_category instances should be singletons, there's also a method to get/create the instance for each class.
 */

namespace Botan {
namespace TLS {

enum StreamError
   {
   StreamTruncated = 1
   };

//! @brief An error category for errors from the TLS::Stream
struct StreamCategory : public boost::system::error_category
   {
   public:
      const char* name() const noexcept override
         {
         return "Botan TLS Stream";
         }

      std::string message(int value) const override
         {
         switch(value)
            {
            case StreamTruncated:
               return "stream truncated";
            default:
               return "generic error";
            }
         }
   };

inline const StreamCategory& botan_stream_category()
   {
   static StreamCategory category;
   return category;
   }

inline boost::system::error_code make_error_code(Botan::TLS::StreamError e)
   {
   return boost::system::error_code(static_cast<int>(e), Botan::TLS::botan_stream_category());
   }

//! @brief An error category for TLS alerts
struct BotanAlertCategory : boost::system::error_category
   {
   const char* name() const noexcept override
      {
      return "Botan TLS Alert";
      }

   std::string message(int ev) const override
      {
      Botan::TLS::Alert alert(static_cast<Botan::TLS::Alert::Type>(ev));
      return alert.type_string();
      }
   };

inline const BotanAlertCategory& botan_alert_category() noexcept
   {
   static BotanAlertCategory category;
   return category;
   }

inline boost::system::error_code make_error_code(Botan::TLS::Alert::Type c)
   {
   return boost::system::error_code(static_cast<int>(c), Botan::TLS::botan_alert_category());
   }

}  // namespace TLS

//! @brief An error category for errors from Botan (other than TLS alerts)
struct BotanErrorCategory : boost::system::error_category
   {
   const char* name() const noexcept override
      {
      return "Botan";
      }

   std::string message(int ev) const override
      {
      return Botan::to_string(static_cast<Botan::ErrorType>(ev));
      }
   };

inline const BotanErrorCategory& botan_category() noexcept
   {
   static BotanErrorCategory category;
   return category;
   }

inline boost::system::error_code make_error_code(Botan::ErrorType e)
   {
   return boost::system::error_code(static_cast<int>(e), Botan::botan_category());
   }

}  // namespace Botan

 /*
 * Add a template specialization of `is_error_code_enum` for each kind of error to allow automatic conversion to an
 * error code.
 */
namespace boost {
namespace system {

template<> struct is_error_code_enum<Botan::TLS::Alert::Type>
   {
   static const bool value = true;
   };

template<> struct is_error_code_enum<Botan::TLS::StreamError>
   {
   static const bool value = true;
   };

template<> struct is_error_code_enum<Botan::ErrorType>
   {
   static const bool value = true;
   };

}  // namespace system
}  // namespace boost

#endif // BOOST_VERSION
#endif // BOTAN_ASIO_ERROR_H_