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use crate::utils::Counter; use std::io::{self, Read}; /// Wrapper around a `Read` that reports the progress made. /// /// Used to monitor a file downloading or other slow IO task /// in a progress bar. /// /// # Examples /// /// ```rust,no_run /// use std::io::Read; /// use cursive::utils::{Counter, ProgressReader}; /// /// // Read a file and report the progress /// let file = std::fs::File::open("large_file").unwrap(); /// let counter = Counter::new(0); /// let mut reader = ProgressReader::new(counter.clone(), file); /// /// std::thread::spawn(move || { /// // Left as an exercise: use an AtomicBool for a stop condition! /// loop { /// let progress = counter.get(); /// println!("Read {} bytes so far", progress); /// } /// }); /// /// // As we read data, the counter will be updated and the control thread /// // will monitor the progress. /// let mut buffer = Vec::new(); /// reader.read_to_end(&mut buffer).unwrap(); /// ``` #[derive(Clone, Debug)] pub struct ProgressReader<R: Read> { reader: R, counter: Counter, } impl<R: Read> ProgressReader<R> { /// Creates a new `ProgressReader` around `reader`. /// /// `counter` will be updated with the number of bytes read. /// /// You should make sure the progress bar knows how /// many bytes should be received. pub fn new(counter: Counter, reader: R) -> Self { ProgressReader { reader, counter } } /// Unwraps this `ProgressReader`, returning the reader and counter. pub fn deconstruct(self) -> (R, Counter) { (self.reader, self.counter) } } impl<R: Read> Read for ProgressReader<R> { fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { let result = self.reader.read(buf)?; self.counter.tick(result); Ok(result) } }