sendfile_defs_default.hpp

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/*
    restinio
*/

/*!
    Sendfile routine definitions (default implementation via <cstdio>).

    @since v.0.4.3
*/

#pragma once

#include <cstdio>

namespace restinio
{

/** @name Aliases for sendfile operation.
 */
///@{
using file_descriptor_t = std::FILE*;
using file_offset_t = std::int64_t;
using file_size_t = std::uint64_t;
///@}


/** @name File operations.
 * @brief A minimal set of file operations.
 *
 * Incapsulates the details *cstdio* API for a set of file operations neccessary
 * for sendfile_t class implementation.
 */
///@{

//! Get file descriptor which stands for null.
constexpr file_descriptor_t null_file_descriptor(){ return nullptr; }

//! Open file.
inline file_descriptor_t
open_file( const char * file_path )
{
    file_descriptor_t file_descriptor = std::fopen( file_path, "rb" );

    if( null_file_descriptor() == file_descriptor )
    {
        throw exception_t{ fmt::format( "std::fopen failed: '{}'", file_path ) };
    }

    return file_descriptor;
}

//! Get file size.
template < typename META >
META
get_file_meta( file_descriptor_t fd )
{
    file_size_t fsize = 0;

    if( null_file_descriptor() != fd )
    {
        // Obtain file size:
        if( 0 == std::fseek( fd , 0 , SEEK_END ) )
        {
            const auto end_pos = std::ftell( fd );

            if( -1 != end_pos )
            {
                fsize = static_cast< file_size_t >( end_pos );
                std::rewind( fd );
            }
            else
            {
                throw exception_t{ "std::ftell failed" };
            }
        }
        else
        {
            throw exception_t{ "std::fseek failed" };
        }
    }

    // No way to get last modification,
    // Use current time instead.
    return META{ fsize, std::chrono::system_clock::now() };
}

//! Close file by its descriptor.
inline void
close_file( file_descriptor_t fd )
{
    std::fclose( fd );
}
///@}

} /* namespace restinio */