| pub struct Entry { |
| /// The pointer to the object stored in the registry. This is a type-erased |
| /// `Box<T>`. |
| pub ptr: *mut (), |
| /// The function that can be called on the above pointer to drop the object |
| /// and free its allocation. |
| pub drop: unsafe fn(*mut ()), |
| } |
| |
| #[cfg(feature = "slab")] |
| mod slab_impl { |
| use std::cell::UnsafeCell; |
| use std::num::NonZeroUsize; |
| |
| use super::Entry; |
| |
| pub struct Registry(pub slab::Slab<Entry>); |
| |
| thread_local!(static REGISTRY: UnsafeCell<Registry> = UnsafeCell::new(Registry(slab::Slab::new()))); |
| |
| pub use usize as ItemId; |
| |
| pub fn insert(thread_id: NonZeroUsize, entry: Entry) -> ItemId { |
| let _ = thread_id; |
| REGISTRY.with(|registry| unsafe { (*registry.get()).0.insert(entry) }) |
| } |
| |
| pub fn with<R, F: FnOnce(&Entry) -> R>(item_id: ItemId, thread_id: NonZeroUsize, f: F) -> R { |
| let _ = thread_id; |
| REGISTRY.with(|registry| f(unsafe { &*registry.get() }.0.get(item_id).unwrap())) |
| } |
| |
| pub fn remove(item_id: ItemId, thread_id: NonZeroUsize) -> Entry { |
| let _ = thread_id; |
| REGISTRY.with(|registry| unsafe { (*registry.get()).0.remove(item_id) }) |
| } |
| |
| pub fn try_remove(item_id: ItemId, thread_id: NonZeroUsize) -> Option<Entry> { |
| let _ = thread_id; |
| REGISTRY.with(|registry| unsafe { (*registry.get()).0.try_remove(item_id) }) |
| } |
| } |
| |
| #[cfg(not(feature = "slab"))] |
| mod map_impl { |
| use std::cell::UnsafeCell; |
| use std::num::NonZeroUsize; |
| use std::sync::atomic::{AtomicUsize, Ordering}; |
| |
| use super::Entry; |
| |
| pub struct Registry(pub std::collections::HashMap<(NonZeroUsize, NonZeroUsize), Entry>); |
| |
| thread_local!(static REGISTRY: UnsafeCell<Registry> = UnsafeCell::new(Registry(Default::default()))); |
| |
| pub type ItemId = NonZeroUsize; |
| |
| fn next_item_id() -> NonZeroUsize { |
| static COUNTER: AtomicUsize = AtomicUsize::new(1); |
| NonZeroUsize::new(COUNTER.fetch_add(1, Ordering::SeqCst)) |
| .expect("more than usize::MAX items") |
| } |
| |
| pub fn insert(thread_id: NonZeroUsize, entry: Entry) -> ItemId { |
| let item_id = next_item_id(); |
| REGISTRY |
| .with(|registry| unsafe { (*registry.get()).0.insert((thread_id, item_id), entry) }); |
| item_id |
| } |
| |
| pub fn with<R, F: FnOnce(&Entry) -> R>(item_id: ItemId, thread_id: NonZeroUsize, f: F) -> R { |
| REGISTRY.with(|registry| { |
| f(unsafe { &*registry.get() } |
| .0 |
| .get(&(thread_id, item_id)) |
| .unwrap()) |
| }) |
| } |
| |
| pub fn remove(item_id: ItemId, thread_id: NonZeroUsize) -> Entry { |
| REGISTRY |
| .with(|registry| unsafe { (*registry.get()).0.remove(&(thread_id, item_id)).unwrap() }) |
| } |
| |
| pub fn try_remove(item_id: ItemId, thread_id: NonZeroUsize) -> Option<Entry> { |
| REGISTRY.with(|registry| unsafe { (*registry.get()).0.remove(&(thread_id, item_id)) }) |
| } |
| } |
| |
| #[cfg(feature = "slab")] |
| pub use self::slab_impl::*; |
| |
| #[cfg(not(feature = "slab"))] |
| pub use self::map_impl::*; |
| |
| impl Drop for Registry { |
| fn drop(&mut self) { |
| for (_, value) in self.0.iter() { |
| // SAFETY: This function is only called once, and is called with the |
| // pointer it was created with. |
| unsafe { (value.drop)(value.ptr) }; |
| } |
| } |
| } |