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use cursive::traits::*;
use cursive::Vec2;
use cursive::{Cursive, Printer};
use std::collections::VecDeque;
use std::sync::mpsc;
use std::thread;
use std::time::Duration;
// This example will print a stream of logs generated from a separate thread.
//
// We will use a custom view using a channel to receive data asynchronously.
fn main() {
// As usual, create the Cursive root
let mut siv = cursive::default();
let cb_sink = siv.cb_sink().clone();
// We want to refresh the page even when no input is given.
siv.add_global_callback('q', |s| s.quit());
// A channel will communicate data from our running task to the UI.
let (tx, rx) = mpsc::channel();
// Generate data in a separate thread.
thread::spawn(move || {
generate_logs(&tx, cb_sink);
});
// And sets the view to read from the other end of the channel.
siv.add_layer(BufferView::new(200, rx).full_screen());
siv.run();
}
// We will only simulate log generation here.
// In real life, this may come from a running task, a separate process, ...
fn generate_logs(tx: &mpsc::Sender<String>, cb_sink: cursive::CbSink) {
let mut i = 1;
loop {
let line = format!("Interesting log line {}", i);
i += 1;
// The send will fail when the other side is dropped.
// (When the application ends).
if tx.send(line).is_err() {
return;
}
cb_sink.send(Box::new(Cursive::noop)).unwrap();
thread::sleep(Duration::from_millis(30));
}
}
// Let's define a buffer view, that shows the last lines from a stream.
struct BufferView {
// We'll use a ring buffer
buffer: VecDeque<String>,
// Receiving end of the stream
rx: mpsc::Receiver<String>,
}
impl BufferView {
// Creates a new view with the given buffer size
fn new(size: usize, rx: mpsc::Receiver<String>) -> Self {
let mut buffer = VecDeque::new();
buffer.resize(size, String::new());
BufferView { buffer, rx }
}
// Reads available data from the stream into the buffer
fn update(&mut self) {
// Add each available line to the end of the buffer.
while let Ok(line) = self.rx.try_recv() {
self.buffer.push_back(line);
self.buffer.pop_front();
}
}
}
impl View for BufferView {
fn layout(&mut self, _: Vec2) {
// Before drawing, we'll want to update the buffer
self.update();
}
fn draw(&self, printer: &Printer) {
// Print the end of the buffer
for (i, line) in
self.buffer.iter().rev().take(printer.size.y).enumerate()
{
printer.print((0, printer.size.y - 1 - i), line);
}
}
}