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|
use futures::stream::Stream as _;
use snafu::{OptionExt as _, ResultExt as _};
use std::io::Write as _;
#[derive(Debug, snafu::Snafu)]
pub enum Error {
#[snafu(display("invalid command index: {}", idx))]
InvalidCommandIndex { idx: usize },
#[snafu(display("error sending message"))]
Sending,
#[snafu(display("error printing output: {}", source))]
PrintOutput { source: std::io::Error },
#[snafu(display("error during eval: {}", source))]
Eval { source: crate::eval::Error },
}
pub type Result<T> = std::result::Result<T, Error>;
#[derive(Debug)]
pub enum StateEvent {
Line(usize, String, futures::sync::oneshot::Sender<Result<()>>),
}
pub struct State {
r: futures::sync::mpsc::Receiver<StateEvent>,
commands: std::collections::HashMap<usize, Command>,
}
impl State {
pub fn new(r: futures::sync::mpsc::Receiver<StateEvent>) -> Self {
Self {
r,
commands: std::collections::HashMap::new(),
}
}
pub fn eval(
&mut self,
idx: usize,
line: &str,
res: futures::sync::oneshot::Sender<Result<()>>,
) -> std::result::Result<
(),
(futures::sync::oneshot::Sender<Result<()>>, Error),
> {
if self.commands.contains_key(&idx) {
return Err((res, Error::InvalidCommandIndex { idx }));
}
let eval = crate::eval::eval(line).context(Eval);
match eval {
Ok(eval) => {
self.commands.insert(idx, Command::new(eval, res));
}
Err(e) => return Err((res, e)),
}
Ok(())
}
pub fn command_start(
&mut self,
idx: usize,
cmd: &str,
args: &[String],
) -> Result<()> {
let command = self
.commands
.get_mut(&idx)
.context(InvalidCommandIndex { idx })?;
let cmd = cmd.to_string();
let args = args.to_vec();
eprint!("running '{} {:?}'\r\n", cmd, args);
command.cmd = Some(cmd);
command.args = Some(args);
Ok(())
}
pub fn command_output(
&mut self,
idx: usize,
output: &[u8],
) -> Result<()> {
let command = self
.commands
.get_mut(&idx)
.context(InvalidCommandIndex { idx })?;
command.output.append(&mut output.to_vec());
let stdout = std::io::stdout();
let mut stdout = stdout.lock();
stdout.write(output).context(PrintOutput)?;
stdout.flush().context(PrintOutput)?;
Ok(())
}
pub fn command_exit(
&mut self,
idx: usize,
status: std::process::ExitStatus,
) -> Result<()> {
let command = self
.commands
.get_mut(&idx)
.context(InvalidCommandIndex { idx })?;
command.status = Some(status);
eprint!("command exited: {}\r\n", status);
Ok(())
}
fn poll_with_errors(&mut self) -> futures::Poll<(), Error> {
loop {
let mut did_work = false;
match self.r.poll().map_err(|()| unreachable!())? {
futures::Async::Ready(Some(StateEvent::Line(
idx,
line,
res,
))) => {
match self.eval(idx, &line, res) {
Ok(()) => {}
Err((res, e)) => {
res.send(Err(e)).map_err(|_| Error::Sending)?;
}
}
did_work = true;
}
futures::Async::Ready(None) => {
return Ok(futures::Async::Ready(()));
}
futures::Async::NotReady => {}
}
for idx in self.commands.keys().cloned().collect::<Vec<usize>>() {
match self
.commands
.get_mut(&idx)
.unwrap()
.future
.poll()
.context(Eval)?
{
futures::Async::Ready(Some(event)) => match event {
crate::eval::CommandEvent::CommandStart(
cmd,
args,
) => {
self.command_start(idx, &cmd, &args)?;
did_work = true;
}
crate::eval::CommandEvent::Output(out) => {
self.command_output(idx, &out)?;
did_work = true;
}
crate::eval::CommandEvent::CommandExit(status) => {
self.command_exit(idx, status)?;
did_work = true;
}
},
futures::Async::Ready(None) => {
self.commands
.remove(&idx)
.context(InvalidCommandIndex { idx })?
.res
.send(Ok(()))
.map_err(|_| Error::Sending)?;
did_work = true;
}
futures::Async::NotReady => {}
}
}
if !did_work {
return Ok(futures::Async::NotReady);
}
}
}
}
impl futures::future::Future for State {
type Item = ();
type Error = ();
fn poll(&mut self) -> futures::Poll<Self::Item, Self::Error> {
loop {
match self.poll_with_errors() {
Ok(a) => return Ok(a),
Err(e) => {
eprint!("error polling state: {}\r\n", e);
}
}
}
}
}
struct Command {
future: crate::eval::Eval,
res: futures::sync::oneshot::Sender<Result<()>>,
cmd: Option<String>,
args: Option<Vec<String>>,
output: Vec<u8>,
status: Option<std::process::ExitStatus>,
}
impl Command {
fn new(
future: crate::eval::Eval,
res: futures::sync::oneshot::Sender<Result<()>>,
) -> Self {
Self {
future,
res,
cmd: None,
args: None,
output: vec![],
status: None,
}
}
}
|
