swc_atoms/
fast.rs

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1use std::{
2    mem::{transmute_copy, ManuallyDrop},
3    ops::Deref,
4};
5
6use crate::Atom;
7
8/// UnsafeAtom is a wrapper around [Atom] that does not allocate, but extremely
9/// unsafe.
10///
11/// Do not use this unless you know what you are doing.
12///
13/// **Currently, it's considered as a unstable API and may be changed in the
14/// future without a semver bump.**
15#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
16pub struct UnsafeAtom(ManuallyDrop<Atom>);
17
18impl UnsafeAtom {
19    /// # Safety
20    ///
21    ///  - You should ensure that the passed `atom` is not freed.
22    ///
23    /// Some simple solutions to ensure this are
24    ///
25    ///  - Collect all [Atom] and store them somewhere while you are using
26    ///    [UnsafeAtom]
27    ///  - Use [UnsafeAtom] only for short-lived operations where all [Atom] is
28    ///    stored in AST and ensure that the AST is not dropped.
29    #[inline]
30    pub unsafe fn new(atom: &Atom) -> Self {
31        Self(ManuallyDrop::new(transmute_copy(atom)))
32    }
33}
34
35impl Deref for UnsafeAtom {
36    type Target = Atom;
37
38    #[inline]
39    fn deref(&self) -> &Self::Target {
40        &self.0
41    }
42}
43
44impl Clone for UnsafeAtom {
45    #[inline]
46    fn clone(&self) -> Self {
47        unsafe { Self::new(&self.0) }
48    }
49}
50
51impl PartialEq<Atom> for UnsafeAtom {
52    #[inline]
53    fn eq(&self, other: &Atom) -> bool {
54        *self.0 == *other
55    }
56}
swc_atoms/fast.rs

swc_atoms/
fast.rs
