// Copyright (c) 2014-2020 Dr. Colin Hirsch and Daniel Frey

// Please see LICENSE for license or visit https://github.com/taocpp/PEGTL/

#ifndef TAO_PEGTL_INTERNAL_FILE_OPENER_HPP

#define TAO_PEGTL_INTERNAL_FILE_OPENER_HPP

#include <fcntl.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <unistd.h>

#include <utility>

#include "../config.hpp"

#include "../input_error.hpp"

namespace tao

{

   namespace TAO_PEGTL_NAMESPACE

   {

      namespace internal

      {

         struct file_opener

         {

            explicit file_opener( const char* filename )

               : m_source( filename ),

                 m_fd( open() )

            {

            }

            file_opener( const file_opener& ) = delete;

            file_opener( file_opener&& ) = delete;

            ~file_opener() noexcept

            {

               ::close( m_fd );

            }

            void operator=( const file_opener& ) = delete;

            void operator=( file_opener&& ) = delete;

            std::size_t size() const

            {

               struct stat st;  // NOLINT

               errno = 0;

               if( ::fstat( m_fd, &st ) < 0 ) {

                  TAO_PEGTL_THROW_INPUT_ERROR( "unable to fstat() file " << m_source << " descriptor " << m_fd );

               }

               return std::size_t( st.st_size );

            }

            const char* const m_source;

            const int m_fd;

         private:

            int open() const

            {

               errno = 0;

               const int fd = ::open( m_source,  // NOLINT

                                      O_RDONLY

#ifdef O_CLOEXEC

                                         | O_CLOEXEC

#endif

               );

               if( fd >= 0 ) {

                  return fd;

               }

               TAO_PEGTL_THROW_INPUT_ERROR( "unable to open() file " << m_source << " for reading" );

            }

         };

      }  // namespace internal

   }  // namespace TAO_PEGTL_NAMESPACE

}  // namespace tao

#endif