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use std::any::Any;
use std::cell::RefCell;
use std::panic::{self, AssertUnwindSafe};
thread_local!(static LAST_ERROR: RefCell<Option<Box<dyn Any + Send>>> = {
RefCell::new(None)
});
pub fn catch<T, F: FnOnce() -> T>(f: F) -> Option<T> {
match LAST_ERROR.try_with(|slot| slot.borrow().is_some()) {
Ok(true) => return None,
Ok(false) => {}
// we're in thread shutdown, so we're for sure not panicking and
// panicking again will abort, so no need to worry!
Err(_) => {}
}
// Note that `AssertUnwindSafe` is used here as we prevent reentering
// arbitrary code due to the `LAST_ERROR` check above plus propagation of a
// panic after we return back to user code from C.
match panic::catch_unwind(AssertUnwindSafe(f)) {
Ok(ret) => Some(ret),
Err(e) => {
LAST_ERROR.with(|slot| *slot.borrow_mut() = Some(e));
None
}
}
}
pub fn propagate() {
if let Ok(Some(t)) = LAST_ERROR.try_with(|slot| slot.borrow_mut().take()) {
panic::resume_unwind(t)
}
}
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