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|
use core::fmt;
use std::{
fs::File,
io::{self, PipeReader, PipeWriter, Read, Write},
os::fd::{AsFd, BorrowedFd},
process::Stdio,
};
use nix::poll::{PollFd, PollFlags};
pub enum Input {
Stdin,
Pipe(PipeReader),
File(File),
}
pub enum Output {
Stdout,
Pipe(PipeWriter),
File(File),
}
impl From<Input> for Stdio {
fn from(value: Input) -> Self {
match value {
Input::Stdin => Stdio::inherit(),
Input::Pipe(reader) => reader.into(),
Input::File(file) => file.into(),
}
}
}
impl From<Output> for Stdio {
fn from(value: Output) -> Stdio {
match value {
Output::Stdout => Stdio::inherit(),
Output::Pipe(writer) => writer.into(),
Output::File(file) => file.into(),
}
}
}
pub struct Canceler {
tx: PipeWriter,
}
impl Canceler {
pub fn cancel(&mut self) {
let _ = self.tx.write(b".");
}
}
pub struct InputReader {
input: Input,
cancel: PipeReader,
canceled: bool,
}
impl InputReader {
pub fn new(input: Input) -> (InputReader, Canceler) {
let (cancel, tx) = std::io::pipe().unwrap();
(
Self {
input,
cancel,
canceled: false,
},
Canceler { tx },
)
}
}
const TIMEOUT_MS: u16 = 20;
enum PollStatus {
Cancel,
Ready,
Wait,
}
fn check<'a>(
canceled: &mut bool,
cancel: &PipeReader,
fd: BorrowedFd<'a>,
flags: PollFlags,
) -> PollStatus {
if *canceled {
return PollStatus::Cancel;
}
let mut poll_fds = [
PollFd::new(cancel.as_fd(), PollFlags::POLLIN),
PollFd::new(fd, flags),
];
if nix::poll::poll(&mut poll_fds, TIMEOUT_MS).is_err() {
*canceled = true;
return PollStatus::Cancel;
};
if let Some(event) = poll_fds[0].revents() {
if event.contains(PollFlags::POLLIN) {
*canceled = true;
return PollStatus::Cancel;
}
}
if let Some(event) = poll_fds[1].revents() {
if event.contains(flags) {
return PollStatus::Ready;
}
}
PollStatus::Wait
}
impl InputReader {
fn poll(&mut self) -> PollStatus {
let stdin = io::stdin();
let read_fd = match &self.input {
Input::Stdin => stdin.as_fd(),
Input::Pipe(pipe) => pipe.as_fd(),
Input::File(file) => file.as_fd(),
};
check(&mut self.canceled, &self.cancel, read_fd, PollFlags::POLLIN)
}
}
#[derive(Debug, Clone, Copy)]
struct Canceled;
impl fmt::Display for Canceled {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "canceled")
}
}
impl std::error::Error for Canceled {}
impl Read for InputReader {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
loop {
match self.poll() {
PollStatus::Cancel => return Err(io::Error::new(io::ErrorKind::Other, Canceled)),
PollStatus::Ready => (),
PollStatus::Wait => continue,
}
return match &mut self.input {
Input::Stdin => io::stdin().read(buf),
Input::Pipe(reader) => reader.read(buf),
Input::File(file) => file.read(buf),
};
}
}
}
pub struct OutputWriter {
output: Output,
cancel: PipeReader,
canceled: bool,
}
impl OutputWriter {
pub fn new(output: Output) -> (Self, Canceler) {
let (cancel, tx) = std::io::pipe().unwrap();
(
Self {
output,
cancel,
canceled: false,
},
Canceler { tx },
)
}
fn poll(&mut self) -> PollStatus {
let stdout = io::stdout();
let write_fd = match &self.output {
Output::Stdout => stdout.as_fd(),
Output::Pipe(pipe) => pipe.as_fd(),
Output::File(file) => file.as_fd(),
};
check(
&mut self.canceled,
&self.cancel,
write_fd,
PollFlags::POLLOUT,
)
}
}
impl Write for OutputWriter {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
loop {
match self.poll() {
PollStatus::Cancel => return Err(io::Error::new(io::ErrorKind::Other, Canceled)),
PollStatus::Ready => (),
PollStatus::Wait => continue,
}
return match &mut self.output {
Output::Stdout => io::stdout().write(buf),
Output::Pipe(writer) => writer.write(buf),
Output::File(file) => file.write(buf),
};
}
}
fn flush(&mut self) -> io::Result<()> {
match &mut self.output {
Output::Stdout => io::stdout().flush(),
Output::Pipe(writer) => writer.flush(),
Output::File(file) => file.flush(),
}
}
}
impl From<InputReader> for Input {
fn from(value: InputReader) -> Self {
value.input
}
}
impl From<OutputWriter> for Output {
fn from(value: OutputWriter) -> Self {
value.output
}
}
|
