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Code Issues Packages 1 Wiki Activity

serde_v8: fix pointer size assumptions (#15613)

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Will Glozer 2022-08-27 21:35:32 +09:00 • committed by GitHub
parent ec98d86d21
commit 09c256d5eb
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2 changed files with 8 additions and 5 deletions
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9
serde_v8/magic/bytestring.rs
View file

@ -5,6 +5,8 @@ use crate::Error;
use smallvec::SmallVec;
use std::mem::size_of;
const USIZE2X: usize = size_of::<usize>() * 2;
#[derive(
PartialEq,
Eq,
@ -18,14 +20,15 @@ use std::mem::size_of;
)]
#[as_mut(forward)]
#[as_ref(forward)]
pub struct ByteString(SmallVec<[u8; 16]>);
pub struct ByteString(SmallVec<[u8; USIZE2X]>);
impl_magic!(ByteString);
// const-assert that Vec<u8> and SmallVec<[u8; 16]> have a same size.
// const-assert that Vec<u8> and SmallVec<[u8; size_of::<usize>() * 2]> have a same size.
// Note from https://docs.rs/smallvec/latest/smallvec/#union -
// smallvec can still be larger than Vec if the inline buffer is
// larger than two machine words.
const _: () = assert!(size_of::<Vec<u8>>() == size_of::<SmallVec<[u8; 16]>>());
const _: () =
assert!(size_of::<Vec<u8>>() == size_of::<SmallVec<[u8; USIZE2X]>>());
impl ToV8 for ByteString {
fn to_v8<'a>(

4
serde_v8/magic/transl8.rs
View file

@ -105,13 +105,13 @@ pub(crate) unsafe fn opaque_recv<T: ?Sized>(ptr: &T) -> u64 {
/// Transmutes an "opaque" ptr back into a reference
pub(crate) unsafe fn opaque_deref<'a, T>(ptr: u64) -> &'a T {
std::mem::transmute(ptr)
std::mem::transmute(ptr as usize)
}
/// Transmutes & copies the value from the "opaque" ptr
/// NOTE: takes ownership & requires other end to forget its ownership
pub(crate) unsafe fn opaque_take<T>(ptr: u64) -> T {
std::mem::transmute_copy::<T, T>(std::mem::transmute(ptr))
std::mem::transmute_copy::<T, T>(std::mem::transmute(ptr as usize))
}
macro_rules! impl_magic {