text: /*
   * This file is part of the GROMACS molecular simulation package.
   *
   * Copyright (c) 2011,2012,2013,2014,2015 by the GROMACS development team.
   * Copyright (c) 2016,2018,2019,2020, by the GROMACS development team, led by
   * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
   * and including many others, as listed in the AUTHORS file in the
   * top-level source directory and at http://www.gromacs.org.
   *
   * GROMACS is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public License
   * as published by the Free Software Foundation; either version 2.1
   * of the License, or (at your option) any later version.
   *
   * GROMACS is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with GROMACS; if not, see
   * http://www.gnu.org/licenses, or write to the Free Software Foundation,
   * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
   *
   * If you want to redistribute modifications to GROMACS, please
   * consider that scientific software is very special. Version
   * control is crucial - bugs must be traceable. We will be happy to
   * consider code for inclusion in the official distribution, but
   * derived work must not be called official GROMACS. Details are found
   * in the README & COPYING files - if they are missing, get the
   * official version at http://www.gromacs.org.
   *
   * To help us fund GROMACS development, we humbly ask that you cite
   * the research papers on the package. Check out http://www.gromacs.org.
   */
  /*! \libinternal \file
   * \brief
   * Declares functions for OS-independent path handling.
   *
   * \author Teemu Murtola <teemu.murtola@gmail.com>
   * \inlibraryapi
   * \ingroup module_utility
   */
  #ifndef GMX_UTILITY_PATH_H
  #define GMX_UTILITY_PATH_H
  
  #include <string>
  #include <string_view>
  #include <utility>
  #include <vector>
  
  namespace gmx
  {
  
  class Path
  {
  public:
      static bool containsDirectory(const std::string& path);
      static bool isAbsolute(const char* path);
      static bool isAbsolute(const std::string& path);
      static bool isEquivalent(const std::string& path1, const std::string& path2);
  
      static std::string join(const std::string& path1, const std::string& path2);
      static std::string join(const std::string& path1, const std::string& path2, const std::string& path3);
      //! Return a path using directory separators that suit the execution OS.
      static std::string normalize(const std::string& path);
      /*! \brief Returns a copy of the parent path (ie. directory
       * components) of \c input ie. up to but excluding the last
       * directory separator (if one exists).
       *
       * \returns A copy of the parent path-components, or empty if
       * no directory separator exists. */
      static std::string getParentPath(const std::string& input);
      /*! \brief Returns a copy of the filename in \c input
       * ie. after the last directory separator (if one exists). */
      static std::string getFilename(const std::string& input);
      //! Returns whether an extension is present in \c input.
      static bool hasExtension(const std::string& input);
      /*! \brief Returns whether the extension present in \c input
       * matches \c extension (which does not include the separator
       * character). */
      static bool extensionMatches(std::string_view input, std::string_view extension);
      /*! \brief Returns a copy of the input without any trailing
       * extension found in the filename component. */
      static std::string stripExtension(const std::string& input);
      /*! \brief Concatenate \c stringToAdd to a copy of \c input,
       * before any file extension (if one exists), and return the
       * result. */
      static std::string concatenateBeforeExtension(const std::string& input, const std::string& stringToAdd);
  
      static const char* stripSourcePrefix(const char* path);
  
      static bool        exists(const char* path);
      static bool        exists(const std::string& path);
      static std::string getWorkingDirectory();
  
      static void splitPathEnvironment(const std::string& pathEnv, std::vector<std::string>* result);
      static std::vector<std::string> getExecutablePaths();
  
      static std::string resolveSymlinks(const std::string& path);
  
  private:
      // Disallow instantiation.
      Path();
  };
  
  class File
  {
  public:
      struct NotFoundInfo
      {
          NotFoundInfo(const char* filename, const char* message, const char* call, bool wasError, int err) :
              filename(filename),
              message(message),
              call(call),
              wasError(wasError),
              err(err)
          {
          }
  
          const char* filename;
          const char* message;
          const char* call;
          bool        wasError;
          int         err;
      };
  
      static void              returnFalseOnError(const NotFoundInfo& info);
      static void              throwOnError(const NotFoundInfo& info);
      [[noreturn]] static void throwOnNotFound(const NotFoundInfo& info);
  
      typedef void (*NotFoundHandler)(const NotFoundInfo& info);
  
      /*! \brief
       * Checks whether a file exists and is a regular file.
       *
       * \param[in] filename    Path to the file to check.
       * \param[in] onNotFound  Function to call when the file does not
       *     exists or there is an error accessing it.
       * \returns   `true` if \p filename exists and is accessible.
       *
       * Does not throw, unless onNotFound throws.
       */
      static bool exists(const char* filename, NotFoundHandler onNotFound);
      //! \copydoc exists(const char *, NotFoundHandler)
      static bool exists(const std::string& filename, NotFoundHandler onNotFound);
  
  private:
      // Disallow instantiation.
      File();
  };
  
  class Directory
  {
  public:
      static int  create(const char* path);
      static int  create(const std::string& path);
      static bool exists(const char* path);
      static bool exists(const std::string& path);
  
  private:
      // Disallow instantiation.
      Directory();
  };
  
  } // namespace gmx
  
  #endif
  