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use crate::cmp;
use crate::ffi::CStr;
use crate::io;
use crate::mem;
use crate::ptr;
use crate::sys::cloudabi::abi;
use crate::sys::time::checked_dur2intervals;
use crate::time::Duration;
pub const DEFAULT_MIN_STACK_SIZE: usize = 2 * 1024 * 1024;
pub struct Thread {
id: libc::pthread_t,
}
// CloudABI has pthread_t as a pointer in which case we still want
// a thread to be Send/Sync
unsafe impl Send for Thread {}
unsafe impl Sync for Thread {}
impl Thread {
// unsafe: see thread::Builder::spawn_unchecked for safety requirements
pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> {
let p = Box::into_raw(box p);
let mut native: libc::pthread_t = mem::zeroed();
let mut attr: libc::pthread_attr_t = mem::zeroed();
assert_eq!(libc::pthread_attr_init(&mut attr), 0);
let stack_size = cmp::max(stack, min_stack_size(&attr));
assert_eq!(libc::pthread_attr_setstacksize(&mut attr, stack_size), 0);
let ret = libc::pthread_create(&mut native, &attr, thread_start, p as *mut _);
// Note: if the thread creation fails and this assert fails, then p will
// be leaked. However, an alternative design could cause double-free
// which is clearly worse.
assert_eq!(libc::pthread_attr_destroy(&mut attr), 0);
return if ret != 0 {
// The thread failed to start and as a result p was not consumed. Therefore, it is
// safe to reconstruct the box so that it gets deallocated.
drop(Box::from_raw(p));
Err(io::Error::from_raw_os_error(ret))
} else {
Ok(Thread { id: native })
};
extern "C" fn thread_start(main: *mut libc::c_void) -> *mut libc::c_void {
unsafe {
// Let's run some code.
Box::from_raw(main as *mut Box<dyn FnOnce()>)();
}
ptr::null_mut()
}
}
pub fn yield_now() {
let ret = unsafe { abi::thread_yield() };
debug_assert_eq!(ret, abi::errno::SUCCESS);
}
pub fn set_name(_name: &CStr) {
// CloudABI has no way to set a thread name.
}
pub fn sleep(dur: Duration) {
let timeout =
checked_dur2intervals(&dur).expect("overflow converting duration to nanoseconds");
unsafe {
let subscription = abi::subscription {
type_: abi::eventtype::CLOCK,
union: abi::subscription_union {
clock: abi::subscription_clock {
clock_id: abi::clockid::MONOTONIC,
timeout,
..mem::zeroed()
},
},
..mem::zeroed()
};
let mut event = mem::MaybeUninit::<abi::event>::uninit();
let mut nevents = mem::MaybeUninit::<usize>::uninit();
let ret = abi::poll(&subscription, event.as_mut_ptr(), 1, nevents.as_mut_ptr());
assert_eq!(ret, abi::errno::SUCCESS);
let event = event.assume_init();
assert_eq!(event.error, abi::errno::SUCCESS);
}
}
pub fn join(self) {
unsafe {
let ret = libc::pthread_join(self.id, ptr::null_mut());
mem::forget(self);
assert!(ret == 0, "failed to join thread: {}", io::Error::from_raw_os_error(ret));
}
}
}
impl Drop for Thread {
fn drop(&mut self) {
let ret = unsafe { libc::pthread_detach(self.id) };
debug_assert_eq!(ret, 0);
}
}
#[cfg_attr(test, allow(dead_code))]
pub mod guard {
pub type Guard = !;
pub unsafe fn current() -> Option<Guard> {
None
}
pub unsafe fn init() -> Option<Guard> {
None
}
}
fn min_stack_size(_: *const libc::pthread_attr_t) -> usize {
libc::PTHREAD_STACK_MIN
}
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