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use crate::ffi::CStr;
use crate::io;
use crate::sys::{unsupported, Void};
use crate::time::Duration;
pub struct Thread(Void);
pub const DEFAULT_MIN_STACK_SIZE: usize = 4096;
impl Thread {
// unsafe: see thread::Builder::spawn_unchecked for safety requirements
pub unsafe fn new(_stack: usize, _p: Box<dyn FnOnce()>)
-> io::Result<Thread>
{
unsupported()
}
pub fn yield_now() {
// do nothing
}
pub fn set_name(_name: &CStr) {
// nope
}
#[cfg(not(target_feature = "atomics"))]
pub fn sleep(_dur: Duration) {
panic!("can't sleep");
}
#[cfg(target_feature = "atomics")]
pub fn sleep(dur: Duration) {
use crate::arch::wasm32;
use crate::cmp;
// Use an atomic wait to block the current thread artificially with a
// timeout listed. Note that we should never be notified (return value
// of 0) or our comparison should never fail (return value of 1) so we
// should always only resume execution through a timeout (return value
// 2).
let mut nanos = dur.as_nanos();
while nanos > 0 {
let amt = cmp::min(i64::max_value() as u128, nanos);
let mut x = 0;
let val = unsafe { wasm32::i32_atomic_wait(&mut x, 0, amt as i64) };
debug_assert_eq!(val, 2);
nanos -= amt;
}
}
pub fn join(self) {
match self.0 {}
}
}
pub mod guard {
pub type Guard = !;
pub unsafe fn current() -> Option<Guard> { None }
pub unsafe fn init() -> Option<Guard> { None }
}
cfg_if::cfg_if! {
if #[cfg(all(target_feature = "atomics", feature = "wasm-bindgen-threads"))] {
#[link(wasm_import_module = "__wbindgen_thread_xform__")]
extern {
fn __wbindgen_current_id() -> u32;
fn __wbindgen_tcb_get() -> u32;
fn __wbindgen_tcb_set(ptr: u32);
}
pub fn my_id() -> u32 {
unsafe { __wbindgen_current_id() }
}
// These are currently only ever used in `thread_local_atomics.rs`, if
// you'd like to use them be sure to update that and make sure everyone
// agrees what's what.
pub fn tcb_get() -> *mut u8 {
use crate::mem;
assert_eq!(mem::size_of::<*mut u8>(), mem::size_of::<u32>());
unsafe { __wbindgen_tcb_get() as *mut u8 }
}
pub fn tcb_set(ptr: *mut u8) {
unsafe { __wbindgen_tcb_set(ptr as u32); }
}
// FIXME: still need something for hooking exiting a thread to free
// data...
} else if #[cfg(target_feature = "atomics")] {
pub fn my_id() -> u32 {
panic!("thread ids not implemented on wasm with atomics yet")
}
pub fn tcb_get() -> *mut u8 {
panic!("thread local data not implemented on wasm with atomics yet")
}
pub fn tcb_set(_ptr: *mut u8) {
panic!("thread local data not implemented on wasm with atomics yet")
}
} else {
// stubbed out because no functions actually access these intrinsics
// unless atomics are enabled
}
}
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