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use std::ffi::OsStr;
use std::process::{Command, Stdio};
use std::{cmp, io};
#[cfg(not(windows))]
use std::os::unix::process::CommandExt;
#[cfg(windows)]
use std::os::windows::process::CommandExt;
#[cfg(windows)]
use winapi::um::winbase::{CREATE_NEW_PROCESS_GROUP, CREATE_NO_WINDOW};
/// Threading utilities.
pub mod thread {
/// Like `thread::spawn`, but with a `name` argument.
pub fn spawn_named<F, T, S>(name: S, f: F) -> ::std::thread::JoinHandle<T>
where
F: FnOnce() -> T + Send + 'static,
T: Send + 'static,
S: Into<String>,
{
::std::thread::Builder::new().name(name.into()).spawn(f).expect("thread spawn works")
}
pub use std::thread::*;
}
pub fn limit<T: Ord>(value: T, min: T, max: T) -> T {
cmp::min(cmp::max(value, min), max)
}
#[cfg(not(windows))]
pub fn start_daemon<I, S>(program: &str, args: I) -> io::Result<()>
where
I: IntoIterator<Item = S>,
S: AsRef<OsStr>,
{
unsafe {
Command::new(program)
.args(args)
.stdin(Stdio::null())
.stdout(Stdio::null())
.stderr(Stdio::null())
.pre_exec(|| {
match ::libc::fork() {
-1 => return Err(io::Error::last_os_error()),
0 => (),
_ => ::libc::_exit(0),
}
if ::libc::setsid() == -1 {
return Err(io::Error::last_os_error());
}
Ok(())
})
.spawn()?
.wait()
.map(|_| ())
}
}
#[cfg(windows)]
pub fn start_daemon<I, S>(program: &str, args: I) -> io::Result<()>
where
I: IntoIterator<Item = S>,
S: AsRef<OsStr>,
{
// Setting all the I/O handles to null and setting the
// CREATE_NEW_PROCESS_GROUP and CREATE_NO_WINDOW has the effect
// that console applications will run without opening a new
// console window.
Command::new(program)
.args(args)
.stdin(Stdio::null())
.stdout(Stdio::null())
.stderr(Stdio::null())
.creation_flags(CREATE_NEW_PROCESS_GROUP | CREATE_NO_WINDOW)
.spawn()
.map(|_| ())
}
#[cfg(test)]
mod tests {
use super::limit;
#[test]
fn limit_works() {
assert_eq!(10, limit(10, 0, 100));
assert_eq!(10, limit(5, 10, 100));
assert_eq!(100, limit(1000, 10, 100));
}
}
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