unzip file which contains symbolic link by zip-rs

zip-rs does not support symbolic link yet(https://github.com/zip-rs/zip/issues/77). However it is possible by using public APIs as below.

use std::fs;
use std::io;

fn main() {
    std::process::exit(real_main());
}

fn real_main() -> i32 {
    let args: Vec<_> = std::env::args().collect();
    if args.len() < 2 {
        println!("Usage: {} <filename>", args[0]);
        return 1;
    }
    let fname = std::path::Path::new(&*args[1]);
    let file = fs::File::open(&fname).unwrap();

    let mut archive = zip::ZipArchive::new(file).unwrap();

    for i in 0..archive.len() {
        let mut file = archive.by_index(i).unwrap();
        let outpath = match file.enclosed_name() {
            Some(path) => path.to_owned(),
            None => continue,
        };

        {
            let comment = file.comment();
            if !comment.is_empty() {
                println!("File {} comment: {}", i, comment);
            }
        }

        if (&*file.name()).ends_with('/') {
            println!("File {} extracted to \"{}\"", i, outpath.display());
            fs::create_dir_all(&outpath).unwrap();
        } else {
            println!(
                "File {} extracted to \"{}\" ({} bytes)",
                i,
                outpath.display(),
                file.size()
            );
            if let Some(p) = outpath.parent() {
                if !p.exists() {
                    fs::create_dir_all(&p).unwrap();
                }
            }

            let is_symlink = if cfg!(unix) {
                const S_IFLINK: u32 = 0o120000;
                file.unix_mode().unwrap() & S_IFLINK == S_IFLINK
            } else {
                false
            };

            if is_symlink {
                #[cfg(unix)]
                {
                    use std::io::Read;
                    use std::os::unix::fs;

                    let mut data = Vec::new();
                    file.read_to_end(&mut data).unwrap();
                    let original = String::from_utf8(data).unwrap();
                    fs::symlink(original, outpath).unwrap();
                }
            } else {
                let mut outfile = fs::File::create(&outpath).unwrap();
                io::copy(&mut file, &mut outfile).unwrap();
                // Get and Set permissions
                #[cfg(unix)]
                {
                    use std::os::unix::fs::PermissionsExt;

                    if let Some(mode) = file.unix_mode() {
                        fs::set_permissions(&outpath, fs::Permissions::from_mode(mode)).unwrap();
                    }
                }
            }
        }
    }

    return 0;
}