Sha256: 9ef0d9e79ee3d5dd32360cf27ffae2d9382fe735b118c1e005ce4f5fff0f5aa5
Contents?: true
Size: 1.11 KB
Versions: 5
Compression:
Stored size: 1.11 KB
Contents
//! This module contains a type that can make `Send + !Sync` types `Sync` by
//! disallowing all immutable access to the value.
//!
//! A similar primitive is provided in the `sync_wrapper` crate.
use std::any::Any;
pub(crate) struct SyncWrapper<T> {
value: T,
}
// safety: The SyncWrapper being send allows you to send the inner value across
// thread boundaries.
unsafe impl<T: Send> Send for SyncWrapper<T> {}
// safety: An immutable reference to a SyncWrapper is useless, so moving such an
// immutable reference across threads is safe.
unsafe impl<T> Sync for SyncWrapper<T> {}
impl<T> SyncWrapper<T> {
pub(crate) fn new(value: T) -> Self {
Self { value }
}
pub(crate) fn into_inner(self) -> T {
self.value
}
}
impl SyncWrapper<Box<dyn Any + Send>> {
/// Attempt to downcast using `Any::downcast_ref()` to a type that is known to be `Sync`.
pub(crate) fn downcast_ref_sync<T: Any + Sync>(&self) -> Option<&T> {
// SAFETY: if the downcast fails, the inner value is not touched,
// so no thread-safety violation can occur.
self.value.downcast_ref()
}
}
Version data entries
5 entries across 5 versions & 1 rubygems