error.hpp

/******************************************************************************
 ------------- Copyright (c) 2009-2023 H a r a l d  A c h i t z ---------------
 ---------- < h a r a l d dot a c h i t z at g m a i l dot c o m > ------------
 ---- This Source Code Form is subject to the terms of the Mozilla Public -----
 ---- License, v. 2.0. If a copy of the MPL was not distributed with this -----
 ---------- file, You can obtain one at http://mozilla.org/MPL/2.0/. ----------
 ******************************************************************************/
 
#ifndef SL3__ERROR_HPP_
#define SL3__ERROR_HPP_
 
#include <exception>
#include <iosfwd>
#include <stdexcept>
#include <string>
 
#include <sl3/config.hpp>
 
namespace sl3
{
  /**
   * \brief Error codes
   *
   * These enum values are used to create ErrType objects.
   *
   * Each ErrCode becomes an ErrType object.
   *
   */
  enum class ErrCode
  {
    SQL3Error       = 1, ///< sqlite3 error happened
    NoConnection    = 2, ///< no database
    OutOfRange      = 5, ///< index op out of range
    TypeMisMatch    = 6, ///< type cast problem
    NullValueAccess = 7, ///< accessing a value that is Null
    UNEXPECTED      = 99 ///< for everything that happens unexpected
  };
 
  /**
   * \brief Get the textual representation (the name) of an ErrCode
   * \param ec
   * wanted ErrCode name
   * \return the ErrCode name
   */
  constexpr const char*
  ErrCodeName (ErrCode ec)
  {
    return ec == ErrCode::SQL3Error         ? "SQLite3Error"
           : ec == ErrCode::NoConnection    ? "NoConnection"
           : ec == ErrCode::OutOfRange      ? "OutOfRange"
           : ec == ErrCode::TypeMisMatch    ? "TypeMisMatch"
           : ec == ErrCode::NullValueAccess ? "NullValueAccess"
           : ec == ErrCode::UNEXPECTED      ? "UNEXPECTED"
                                            : "NA";
  }
 
  /**
   * \brief Exception base type
   *
   * A common base for all ErrType objects.
   * All exceptions thrown by the
   * library will have this base type.
   */
  class LIBSL3_API Error : public std::runtime_error
  {
  protected:
  public:
    /// Inherit constructors from std::runtime_error
    using std::runtime_error::runtime_error;
 
    /**
     * \brief Get ErrCode
     * \return the ErrCode of the exception
     */
    virtual ErrCode getId () const = 0;
  };
 
  /**
   * \brief Overloaded stream operator
   * \param os ostream
   * \param e the Error
   * \return the ostream
   */
  LIBSL3_API std::ostream& operator<< (std::ostream& os, const Error& e);
 
  /**
   * \brief Object class representing an ErrCode
   *
   *  Allows typedefs using an ErrCode.
   *  Each sl3::ErrCode becomes
   * an ErrType object.
   */
  template <ErrCode ec> class LIBSL3_API ErrType final : public Error
  {
  public:
    ErrType ()
    : Error ("")
    {
    }
 
    using Error::Error;
 
    ErrCode
    getId () const override
    {
      return ec;
    }
  };
 
  /// error that will be thrown if no open database was available but needed
  using ErrNoConnection = ErrType<ErrCode::NoConnection>;
 
  /// thrown if an index op is out of range
  using ErrOutOfRange = ErrType<ErrCode::OutOfRange>;
 
  /**
   * \brief thrown in case of an incorrect type usage
   */
  using ErrTypeMisMatch = ErrType<ErrCode::TypeMisMatch>;
 
  /// thrown in case of accessing a Null value field/parameter
  using ErrNullValueAccess = ErrType<ErrCode::NullValueAccess>;
 
  /// thrown if something unexpected happened, mostly used by test tools and in
  /// debug mode
  using ErrUnexpected = ErrType<ErrCode::UNEXPECTED>;
 
  /**
   * \brief Package an error from sqlite3.
   * This exception will be thrown if sqlite3 reports an error.
   *
   * Holds the sqlite3 error code and the error message if it is available.
   * \see Database::getMostRecentErrMsg
   * \see Database::getMostRecentErrCode
   *
   * \n Extended error codes can be obtained through Database class.
   * \see Database::getMostRecentExtendedErrCode
   * \see Database::enableExtendedResultCodes
   *
   */
  template <> class LIBSL3_API ErrType<ErrCode::SQL3Error> final : public Error
  {
  public:
    /**
     * \brief c'tor
     * \param sl3ec sqlite error code
     * \param sl3msg sqlite error
     * message
     * \param msg additional message
     */
    ErrType (int sl3ec, const char* sl3msg, const std::string& msg)
    : Error ("(" + std::to_string (sl3ec) + ":" + sl3msg + "):" + msg)
    , _sqlite_ec (sl3ec)
    , _sqlite_msg (sl3msg)
    {
    }
 
    /**
     * \brief c'tor
     * \param sl3ec sqlite error code
     * \param sl3msg sqlite error
     * message
     */
    ErrType (int sl3ec, const char* sl3msg)
    : ErrType (sl3ec, sl3msg, "")
    {
    }
    ErrCode
    getId () const override
    {
      return ErrCode::SQL3Error;
    }
 
    /**
     * \brief  Get the sqlite3 error code
     * \return the sqlite3 error code
     */
    int
    SQLiteErrorCode () const
    {
      return _sqlite_ec;
    }
 
    /**
     * \brief  Get the sqlite3 error message.
     *
     * If the exception was created with a sqlite error message,
     * it can
     * be accessed here.
     *
     * \return the sqlite3 error message
     */
    const std::string&
    SQLiteErrorMessage () const
    {
      return _sqlite_msg;
    };
 
  private:
    int         _sqlite_ec;
    std::string _sqlite_msg;
  };
 
  /**
   * \brief Alias for ErrType<ErrCode::SQL3Error>
   *
   * A short alias for an ErrType<ErrCode::SQL3Error>
   */
  using SQLite3Error = ErrType<ErrCode::SQL3Error>;
 
#define ASSERT_EXCEPT(exp, except) \
  if (!(exp))                      \
  throw except (std::string (__FUNCTION__) + ": " + #exp)
 
  /*
    TODO check if this can be done, together with __FUNCTION__,
    into a nice
  code location for clearer messages
    File.cpp::Function::39 The problem
 
 
    using cstr = const char * const;
 
    static constexpr cstr past_last_slash(cstr str, cstr last_slash)
    {
        return
            *str == '\0' ? last_slash :
            *str == '/'  ? past_last_slash(str + 1, str + 1) :
                           past_last_slash(str + 1, last_slash);
    }
 
    static constexpr cstr past_last_slash(cstr str)
    {
        return past_last_slash(str, str);
    }
 
  #define __SHORT_FILE__ ({constexpr cstr sf__ {past_last_slash(__FILE__)};
  sf__;})
 
  */
 
} // ns
 
#endif /* ...ERROR_HPP_ */