//! Re-open a `fs::File` to produce an independent handle.

use crate::fs::{is_file_read_write, is_same_file, reopen_impl, OpenOptions};

use std::{fs, io};

/// Re-open an `fs::File` to produce an independent handle.

///

/// This operation isn't supported by all operating systems in all

/// circumstances, or in some operating systems in any circumstances,

/// so it may return an `io::ErrorKind::Other` error if the file

/// cannot be reopened.

#[inline]

pub fn reopen(file: &fs::File, options: &OpenOptions) -> io::Result<fs::File> {

    let (read, write) = is_file_read_write(file)?;

    // Don't grant more rights than the original file had. And don't allow

    // it to create a file.

    if options.create

        || options.create_new

        || (!read && options.read)

        || (!write && (options.write || options.append || options.truncate))

    {

        return Err(io::Error::new(

            io::ErrorKind::PermissionDenied,

            "Couldn't reopen file",

        ));

    }

    let new = reopen_impl(file, options)?;

    if !is_same_file(file, &new)? {

        return Err(io::Error::new(io::ErrorKind::Other, "Couldn't reopen file"));

    }

    Ok(new)

}