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use {CANCELLED_TWICE, POLLED_TWICE, Spawn};
use conch_parser::ast;
use env::{FileDescEnvironment, SubEnvironment};
use future::{EnvFuture, Poll};
use io::FileDesc;
use spawn::{ExitResult, Pipeline, pipeline, SpawnedPipeline};
use std::fmt;
use std::io;
use std::iter;
#[must_use = "futures do nothing unless polled"]
pub struct ListableCommand<S, E>
where S: Spawn<E>,
{
state: State<Pipeline<S, E>>,
}
impl<S, E> fmt::Debug for ListableCommand<S, E>
where S: Spawn<E> + fmt::Debug,
S::EnvFuture: fmt::Debug,
S::Future: fmt::Debug,
S::Error: fmt::Debug,
E: fmt::Debug,
{
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
fmt.debug_struct("ListableCommand")
.field("state", &self.state)
.finish()
}
}
#[derive(Debug)]
enum State<F> {
Init(Option<io::Result<F>>),
Spawned(F),
}
impl<S, E> Spawn<E> for ast::ListableCommand<S>
where S: Spawn<E>,
S::Error: From<io::Error>,
E: FileDescEnvironment + SubEnvironment,
E::FileHandle: From<FileDesc> + Clone,
{
type EnvFuture = ListableCommand<S, E>;
type Future = ExitResult<SpawnedPipeline<S, E>>;
type Error = S::Error;
fn spawn(self, env: &E) -> Self::EnvFuture {
let pipeline = match self {
ast::ListableCommand::Single(cmd) => pipeline(false, iter::once(cmd), env),
ast::ListableCommand::Pipe(invert, cmds) => pipeline(invert, cmds, env),
};
ListableCommand {
state: State::Init(Some(pipeline)),
}
}
}
impl<'a, S: 'a, E> Spawn<E> for &'a ast::ListableCommand<S>
where &'a S: Spawn<E>,
<&'a S as Spawn<E>>::Error: From<io::Error>,
E: FileDescEnvironment + SubEnvironment,
E::FileHandle: From<FileDesc> + Clone,
{
type EnvFuture = ListableCommand<&'a S, E>;
type Future = ExitResult<SpawnedPipeline<&'a S, E>>;
type Error = <&'a S as Spawn<E>>::Error;
fn spawn(self, env: &E) -> Self::EnvFuture {
let pipeline = match *self {
ast::ListableCommand::Single(ref cmd) => pipeline(false, iter::once(cmd), env),
ast::ListableCommand::Pipe(invert, ref cmds) => pipeline(invert, cmds, env),
};
ListableCommand {
state: State::Init(Some(pipeline)),
}
}
}
impl<S, E> EnvFuture<E> for ListableCommand<S, E>
where S: Spawn<E>,
S::Error: From<io::Error>,
E: FileDescEnvironment + SubEnvironment,
E::FileHandle: From<FileDesc> + Clone,
{
type Item = ExitResult<SpawnedPipeline<S, E>>;
type Error = S::Error;
fn poll(&mut self, env: &mut E) -> Poll<Self::Item, Self::Error> {
loop {
let next_state = match self.state {
State::Init(ref mut pipeline) => {
let pipeline = pipeline.take().expect(POLLED_TWICE);
State::Spawned(try!(pipeline))
},
State::Spawned(ref mut f) => return f.poll(env),
};
self.state = next_state;
};
}
fn cancel(&mut self, env: &mut E) {
match self.state {
State::Init(ref mut pipeline) => {
drop(pipeline.take().expect(CANCELLED_TWICE));
},
State::Spawned(ref mut f) => f.cancel(env),
}
}
}