programmerjake/fayalite
1
0
Fork 0
forked from libre-chip/fayalite
Code Pull requests Activity

change TypeIdMap to not use any unsafe code

Browse source
This commit is contained in:
Jacob Lifshay 2025-04-09 16:25:56 -07:00
parent 5967e812a2
commit 9a1b047d2f
Signed by: programmerjake
SSH key fingerprint: SHA256:HnFTLGpSm4Q4Fj502oCFisjZSoakwEuTsJJMSke63RQ
1 changed files with 15 additions and 40 deletions
Download patch file Download diff file Expand all files Collapse all files

55
crates/fayalite/src/intern/type_map.rs
View file

@ -1,10 +1,8 @@
// SPDX-License-Identifier: LGPL-3.0-or-later // SPDX-License-Identifier: LGPL-3.0-or-later
// See Notices.txt for copyright information // See Notices.txt for copyright information
use hashbrown::HashMap;
use std::{ use std::{
any::{Any, TypeId}, any::{Any, TypeId},
hash::{BuildHasher, Hasher}, hash::{BuildHasher, Hasher},
ptr::NonNull,
sync::RwLock, sync::RwLock,
}; };
@ -75,59 +73,36 @@ impl BuildHasher for TypeIdBuildHasher {
} }
} }
struct Value(NonNull<dyn Any + Send + Sync>); pub(crate) struct TypeIdMap(
RwLock<hashbrown::HashMap<TypeId, &'static (dyn Any + Send + Sync), TypeIdBuildHasher>>,
impl Value { );
unsafe fn get_transmute_lifetime<'b>(&self) -> &'b (dyn Any + Send + Sync) {
unsafe { &*self.0.as_ptr() }
}
fn new(v: Box<dyn Any + Send + Sync>) -> Self {
unsafe { Self(NonNull::new_unchecked(Box::into_raw(v))) }
}
}
unsafe impl Send for Value {}
unsafe impl Sync for Value {}
impl Drop for Value {
fn drop(&mut self) {
unsafe { std::ptr::drop_in_place(self.0.as_ptr()) }
}
}
pub struct TypeIdMap(RwLock<HashMap<TypeId, Value, TypeIdBuildHasher>>);
impl TypeIdMap { impl TypeIdMap {
pub const fn new() -> Self { pub(crate) const fn new() -> Self {
Self(RwLock::new(HashMap::with_hasher(TypeIdBuildHasher))) Self(RwLock::new(hashbrown::HashMap::with_hasher(
TypeIdBuildHasher,
)))
} }
#[cold] #[cold]
unsafe fn insert_slow( fn insert_slow(
&self, &self,
type_id: TypeId, type_id: TypeId,
make: fn() -> Box<dyn Any + Sync + Send>, make: fn() -> Box<dyn Any + Sync + Send>,
) -> &(dyn Any + Sync + Send) { ) -> &'static (dyn Any + Sync + Send) {
let value = Value::new(make()); let value = Box::leak(make());
let mut write_guard = self.0.write().unwrap(); let mut write_guard = self.0.write().unwrap();
unsafe { *write_guard.entry(type_id).or_insert(value)
write_guard
.entry(type_id)
.or_insert(value)
.get_transmute_lifetime()
}
} }
pub fn get_or_insert_default<T: Sized + Any + Send + Sync + Default>(&self) -> &T { pub(crate) fn get_or_insert_default<T: Sized + Any + Send + Sync + Default>(&self) -> &T {
let type_id = TypeId::of::<T>(); let type_id = TypeId::of::<T>();
let read_guard = self.0.read().unwrap(); let read_guard = self.0.read().unwrap();
let retval = read_guard let retval = read_guard.get(&type_id).map(|v| *v);
.get(&type_id)
.map(|v| unsafe { Value::get_transmute_lifetime(v) });
drop(read_guard); drop(read_guard);
let retval = match retval { let retval = match retval {
Some(retval) => retval, Some(retval) => retval,
None => unsafe { self.insert_slow(type_id, move || Box::new(T::default())) }, None => self.insert_slow(type_id, move || Box::new(T::default())),
}; };
unsafe { &*(retval as *const dyn Any as *const T) } retval.downcast_ref().expect("known to have correct TypeId")
} }
} }