progress_file.rs

use std::fs::File;
use pbr::ProgressBar;
use std::io::Read;

pub struct ProgressFile {
    file: File,
    progress: ProgressBar<::std::io::Stdout>,
}

impl ProgressFile {
    pub fn new(file: File) -> Result<ProgressFile, ::std::io::Error> {
        let size = file.metadata()?.len();
        let mut progress = ProgressBar::new(size);
        progress.set_units(::pbr::Units::Bytes);
        Ok(ProgressFile { file, progress })
    }
}

impl Read for ProgressFile {
    fn read(&mut self, bytes: &mut [u8]) -> Result<usize, ::std::io::Error> {
        let result = self.file.read(bytes);
        if let Ok(size) = result {
            if unsafe { ::libc::isatty(::libc::STDOUT_FILENO as i32) } != 0 {
                self.progress.add(size as u64);
            }
        }
        result
    }
}