rust/chg/src/main.rs

// Copyright 2018 Yuya Nishihara <[e-mail]>
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.

use chg::locator::{self, Locator};
use chg::procutil;
use chg::{ChgClientExt, ChgUiHandler};
use futures::sync::oneshot;
use std::env;
use std::io;
use std::process;
use std::time::Instant;
use tokio::prelude::*;

struct DebugLogger {
    start: Instant,
}

impl DebugLogger {
    pub fn new() -> DebugLogger {
        DebugLogger {
            start: Instant::now(),
        }
    }
}

impl log::Log for DebugLogger {
    fn enabled(&self, metadata: &log::Metadata) -> bool {
        metadata.target().starts_with("chg::")
    }

    fn log(&self, record: &log::Record) {
        if self.enabled(record.metadata()) {
            // just make the output looks similar to chg of C
            let l = format!("{}", record.level()).to_lowercase();
            let t = self.start.elapsed();
            writeln!(
                io::stderr(),
                "chg: {}: {}.{:06} {}",
                l,
                t.as_secs(),
                t.subsec_micros(),
                record.args()
            )
            .unwrap_or(());
        }
    }

    fn flush(&self) {}
}

fn main() {
    if env::var_os("CHGDEBUG").is_some() {
        log::set_boxed_logger(Box::new(DebugLogger::new()))
            .expect("any logger should not be installed yet");
        log::set_max_level(log::LevelFilter::Debug);
    }

    // TODO: add loop detection by $CHGINTERNALMARK

    let code = run().unwrap_or_else(|err| {
        writeln!(io::stderr(), "chg: abort: {}", err).unwrap_or(());
        255
    });
    process::exit(code);
}

fn run() -> io::Result<i32> {
    let umask = unsafe { procutil::get_umask() }; // not thread safe
    let mut loc = Locator::prepare_from_env()?;
    loc.set_early_args(locator::collect_early_args(env::args_os().skip(1)));
    let handler = ChgUiHandler::new();
    let (result_tx, result_rx) = oneshot::channel();
    let fut = loc
        .connect()
        .and_then(|(_, client)| client.attach_io(io::stdin(), io::stdout(), io::stderr()))
        .and_then(move |client| client.set_umask(umask))
        .and_then(|client| {
            let pid = client.server_spec().process_id.unwrap();
            let pgid = client.server_spec().process_group_id;
            procutil::setup_signal_handler_once(pid, pgid)?;
            Ok(client)
        })
        .and_then(|client| client.run_command_chg(handler, env::args_os().skip(1)))
        .map(|(_client, _handler, code)| {
            procutil::restore_signal_handler_once()?;
            Ok(code)
        })
        .or_else(|err| Ok(Err(err))) // pass back error to caller
        .map(|res| result_tx.send(res).unwrap());
    tokio::run(fut);
    result_rx.wait().unwrap_or(Err(io::Error::new(
        io::ErrorKind::Other,
        "no exit code set",
    )))
}