goldendict-ng/winlibs/include/zim/error.h

/*
 * Copyright (C) 2020 Matthieu Gautier <mgautier@kymeria.fr>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * is provided AS IS, WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, and
 * NON-INFRINGEMENT.  See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 *
 */

#ifndef ZIM_ERROR_H
#define ZIM_ERROR_H

#include "zim.h"

#include <stdexcept>
#include <sstream>
#include <typeinfo>

namespace zim {
class LIBZIM_API ZimFileFormatError: public std::runtime_error
{
public:
  explicit ZimFileFormatError( const std::string & msg ):
    std::runtime_error( msg )
  {
  }
};

class LIBZIM_API InvalidType: public std::logic_error
{
public:
  explicit InvalidType( const std::string & msg ):
    std::logic_error( msg )
  {
  }
};

class LIBZIM_API EntryNotFound: public std::runtime_error
{
public:
  explicit EntryNotFound( const std::string & msg ):
    std::runtime_error( msg )
  {
  }
};

/* Exception thrown by the Creator in case of error.
   *
   * Most exceptions actually thrown are inheriting this exception.
   */
class LIBZIM_API CreatorError: public std::runtime_error
{
public:
  explicit CreatorError( const std::string & message ):
    std::runtime_error( message )
  {
  }
};

/* Exception thrown when a entry cannot be added to the Creator.*/
class LIBZIM_API InvalidEntry: public CreatorError
{
public:
  explicit InvalidEntry( const std::string & message ):
    CreatorError( message )
  {
  }
};

/* Exception thrown if a incoherence in the user implementation has been detected.
   *
   * Users need to implement interfaces such as:
   * - ContentProvider
   * - IndexData
   * - Item
   *
   * If a incoherence has been detected in those implementations a
   * `IncoherentImplementationError` will be thrown.
   */
class LIBZIM_API IncoherentImplementationError: public CreatorError
{
public:
  explicit IncoherentImplementationError( const std::string & message ):
    CreatorError( message )
  {
  }
};

/* Exception thrown in the main thread when another exception has been
   * thrown in another worker thread.
   *
   * Creator uses different worker threads to do background work.
   * If an exception is thrown in one of this threads, it is catched and
   * "rethrown" in the main thread as soon as possible with a `AsyncError`.
   *
   * AsyncError contains the original exception. You can rethrow the original
   * exception using `rethrow`:
   *
   * ```
   * try {
   *   creator->addStuff(...);
   * } catch (const zim::AsyncError& e) {
   *   // An exception has been thrown in a worker thread
   *   try {
   *     e.rethrow();
   *   } catch (const std::exception& original_exception) {
   *     // original_exception is the exception thrown in the worker thread
   *     ...
   *   }
   * }
   * ```
   */
class LIBZIM_API AsyncError: public CreatorError
{
public:
  explicit AsyncError( const std::exception_ptr exception ):
    CreatorError( buildErrorMessage( exception ) ),
    m_exception( exception )
  {
  }

  [[noreturn]] void rethrow() const
  {
    std::rethrow_exception( m_exception );
  }

private: // data
  std::exception_ptr m_exception;

private: // function
  static std::string buildErrorMessage( const std::exception_ptr exception )
  {
    try {
      std::rethrow_exception( exception );
    }
    catch ( const std::exception & e ) {
      std::stringstream ss;
      ss << "Asynchronous error: ";
      ss << typeid( e ).name() << std::endl;
      ss << e.what();
      return ss.str();
    }
    catch ( ... ) {
      return "Unknown asynchronous exception";
    }
  }
};

/* Exception thrown when the creator is in error state.
   *
   * If the creator is in error state (mostly because a AsyncError has already
   * being thrown), any call to any method on it will thrown a `CreatorStateError`.
   */
class LIBZIM_API CreatorStateError: public CreatorError
{
public:
  explicit CreatorStateError():
    CreatorError( "Creator is in error state." )
  {
  }
};
} // namespace zim

#endif // ZIM_ERROR_H