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#![no_std]
pub use bare_metal::CriticalSection;
#[inline]
pub unsafe fn acquire() -> u8 {
extern "Rust" {
fn _critical_section_acquire() -> u8;
}
_critical_section_acquire()
}
#[inline]
pub unsafe fn release(token: u8) {
extern "Rust" {
fn _critical_section_release(token: u8);
}
_critical_section_release(token)
}
#[inline]
pub fn with<R>(f: impl FnOnce(CriticalSection) -> R) -> R {
unsafe {
let token = acquire();
let r = f(CriticalSection::new());
release(token);
r
}
}
cfg_if::cfg_if! {
if #[cfg(feature = "custom-impl")] {
pub unsafe trait Impl {
unsafe fn acquire() -> u8;
unsafe fn release(token: u8);
}
#[macro_export]
macro_rules! custom_impl {
($t: ty) => {
#[no_mangle]
unsafe fn _critical_section_acquire() -> u8 {
<$t as $crate::Impl>::acquire()
}
#[no_mangle]
unsafe fn _critical_section_release(token: u8) {
<$t as $crate::Impl>::release(token)
}
};
}
} else if #[cfg(cortex_m)] {
#[no_mangle]
unsafe fn _critical_section_acquire() -> u8 {
let primask = cortex_m::register::primask::read();
cortex_m::interrupt::disable();
primask.is_active() as _
}
#[no_mangle]
unsafe fn _critical_section_release(token: u8) {
if token != 0 {
cortex_m::interrupt::enable()
}
}
} else if #[cfg(any(unix, windows))] {
extern crate std;
static INIT: std::sync::Once = std::sync::Once::new();
static mut GLOBAL_LOCK: Option<std::sync::Mutex<()>> = None;
static mut GLOBAL_GUARD: Option<std::sync::MutexGuard<'static, ()>> = None;
#[no_mangle]
unsafe fn _critical_section_acquire() -> u8 {
INIT.call_once(|| unsafe {
GLOBAL_LOCK.replace(std::sync::Mutex::new(()));
});
let guard = GLOBAL_LOCK.as_ref().unwrap().lock().unwrap();
GLOBAL_GUARD.replace(guard);
1
}
#[no_mangle]
unsafe fn _critical_section_release(token: u8) {
if token == 1 {
GLOBAL_GUARD.take();
}
}
} else {
compile_error!("Critical section is not implemented for this target. Make sure you've specified the correct --target. You may need to supply a custom critical section implementation with the `custom-impl` feature");
}
}