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use std::io::{BufWriter, Write};
use std::os::fd::{AsRawFd, RawFd};
use std::process::{Child, ChildStdin, ChildStdout, Command, Stdio};
use anyhow::Result;
use nix::errno::Errno;
use nix::libc;
use crate::i3bar_protocol::{Block, Event, Protocol};
#[derive(Debug)]
pub struct StatusCmd {
pub child: Child,
pub output: ChildStdout,
input: BufWriter<ChildStdin>,
protocol: Protocol,
buf: Vec<u8>,
}
impl StatusCmd {
pub fn new(cmd: &str) -> Result<Self> {
let mut child = Command::new("sh")
.args(["-c", &format!("exec {cmd}")])
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.spawn()?;
let output = child.stdout.take().unwrap();
let input = BufWriter::new(child.stdin.take().unwrap());
nix::fcntl::fcntl(
output.as_raw_fd(),
nix::fcntl::F_SETFL(nix::fcntl::OFlag::O_NONBLOCK),
)?;
Ok(Self {
child,
output,
input,
protocol: Protocol::Unknown,
buf: Vec::new(),
})
}
pub fn receive_blocks(&mut self) -> Result<Option<Vec<Block>>> {
match read_to_vec(self.output.as_raw_fd(), &mut self.buf) {
Ok(0) => bail!("status command exited"),
Ok(_n) => (),
Err(Errno::EAGAIN) => return Ok(None),
Err(e) => bail!(e),
}
let rem = self.protocol.process_new_bytes(&self.buf)?;
let used = self.buf.len() - rem.len();
self.buf.drain(..used);
Ok(self.protocol.get_blocks())
}
pub fn send_click_event(&mut self, event: &Event) -> Result<()> {
if self.protocol.supports_clicks() {
serde_json::to_writer(&mut self.input, event)?;
self.input.write_all(b"\n")?;
self.input.flush()?;
}
Ok(())
}
}
/// Read from a raw file descriptor to the vector.
///
/// Appends data at the end of the buffer. Resizes vector as needed.
pub fn read_to_vec(fd: RawFd, buf: &mut Vec<u8>) -> nix::Result<usize> {
if buf.capacity() - buf.len() < 1024 {
buf.reserve(buf.capacity().max(1024));
}
let res = unsafe {
libc::read(
fd,
buf.as_mut_ptr().add(buf.len()) as *mut libc::c_void,
(buf.capacity() - buf.len()) as libc::size_t,
)
};
let read = Errno::result(res)? as usize;
unsafe { buf.set_len(buf.len() + read) };
Ok(read)
}
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