maxmind_error_category.h

#ifndef MAXMIND_C_LIB_PRACTICE_MAXMIND_ERROR_CATEGORY_H
#define MAXMIND_C_LIB_PRACTICE_MAXMIND_ERROR_CATEGORY_H

#include <maxminddb.h>
#include <system_error>

namespace geo_ip_loader {

/// Errors defined in maxminddb.h, converted to C++ enums.
enum class MMDBStatus {
	success						= MMDB_SUCCESS								,	///<= 0
	file_open					= MMDB_FILE_OPEN_ERROR						,	///<= 1
	corrupt_search_tree			= MMDB_CORRUPT_SEARCH_TREE_ERROR			,	///<= 2
	invalid_metadata			= MMDB_INVALID_METADATA_ERROR				,	///<= 3
	io							= MMDB_IO_ERROR								,	///<= 4
	out_of_memory				= MMDB_OUT_OF_MEMORY_ERROR					,	///<= 5
	unknown_db_format			= MMDB_UNKNOWN_DATABASE_FORMAT_ERROR		,	///<= 6
	invalid_data				= MMDB_INVALID_DATA_ERROR					,	///<= 7
	invalid_lookup_path			= MMDB_INVALID_LOOKUP_PATH_ERROR			,	///<= 8
	lookup_path_does_not_match	= MMDB_LOOKUP_PATH_DOES_NOT_MATCH_DATA_ERROR,	///<= 9
	invalid_node_number			= MMDB_INVALID_NODE_NUMBER_ERROR			,	///<= 10
	ipv6_lookup_in_ipv4_db		= MMDB_IPV6_LOOKUP_IN_IPV4_DATABASE_ERROR		///<= 11
};

/** Error class used to return libmaxminddb error codes and messages when C++ exceptions are thrown.
 * @see @p MMDB_strerror()
 */
class ErrorCategory : public std::error_category
{
public:

	/// Returns a unique name.
	virtual const char *name( void ) const noexcept;

	/// Convert a MaxMindDB error/status code into a readable text string message.
	virtual std::string message( int code ) const;
};

/// All error category objects should actually be references to the exact same object, which is provided by this function.
const ErrorCategory &get_error_category( void ) noexcept;

/// Associate an error value with the category.
std::error_code make_error_code( MMDBStatus s );

/// Associate an error_condition with the category.
std::error_condition make_error_condition( MMDBStatus s );

} // namespace geo_ip_loader

namespace std
{

/// Make sure that MMDBStatus enums can be converted to error codes.
template <>
struct is_error_code_enum<geo_ip_loader::MMDBStatus> : public true_type {};

} // namespace std


#endif //MAXMIND_C_LIB_PRACTICE_MAXMIND_ERROR_CATEGORY_H