4924cf5828
Hiya! # Objective - Remove upcasting methods that are no longer necessary since Rust 1.86. - Cleanup the interned label code. ## Notes - I didn't try to remove the upcasting methods from `bevy_reflect`, as there appears to be some complexity related to remote type reflection. - There are likely some other upcasting methods floating around. ## Testing I ran the `breakout` example to check that the hashing/eq implementations of the labels are still correct. --------- Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
96 lines
3.4 KiB
Rust
96 lines
3.4 KiB
Rust
use proc_macro::{TokenStream, TokenTree};
|
|
use quote::{quote, quote_spanned};
|
|
use std::collections::HashSet;
|
|
use syn::{spanned::Spanned, Ident};
|
|
|
|
/// Finds an identifier that will not conflict with the specified set of tokens.
|
|
///
|
|
/// If the identifier is present in `haystack`, extra characters will be added
|
|
/// to it until it no longer conflicts with anything.
|
|
///
|
|
/// Note that the returned identifier can still conflict in niche cases,
|
|
/// such as if an identifier in `haystack` is hidden behind an un-expanded macro.
|
|
pub fn ensure_no_collision(value: Ident, haystack: TokenStream) -> Ident {
|
|
// Collect all the identifiers in `haystack` into a set.
|
|
let idents = {
|
|
// List of token streams that will be visited in future loop iterations.
|
|
let mut unvisited = vec![haystack];
|
|
// Identifiers we have found while searching tokens.
|
|
let mut found = HashSet::new();
|
|
while let Some(tokens) = unvisited.pop() {
|
|
for t in tokens {
|
|
match t {
|
|
// Collect any identifiers we encounter.
|
|
TokenTree::Ident(ident) => {
|
|
found.insert(ident.to_string());
|
|
}
|
|
// Queue up nested token streams to be visited in a future loop iteration.
|
|
TokenTree::Group(g) => unvisited.push(g.stream()),
|
|
TokenTree::Punct(_) | TokenTree::Literal(_) => {}
|
|
}
|
|
}
|
|
}
|
|
|
|
found
|
|
};
|
|
|
|
let span = value.span();
|
|
|
|
// If there's a collision, add more characters to the identifier
|
|
// until it doesn't collide with anything anymore.
|
|
let mut value = value.to_string();
|
|
while idents.contains(&value) {
|
|
value.push('X');
|
|
}
|
|
|
|
Ident::new(&value, span)
|
|
}
|
|
|
|
/// Derive a label trait
|
|
///
|
|
/// # Args
|
|
///
|
|
/// - `input`: The [`syn::DeriveInput`] for struct that is deriving the label trait
|
|
/// - `trait_name`: Name of the label trait
|
|
/// - `trait_path`: The [path](`syn::Path`) to the label trait
|
|
/// - `dyn_eq_path`: The [path](`syn::Path`) to the `DynEq` trait
|
|
pub fn derive_label(
|
|
input: syn::DeriveInput,
|
|
trait_name: &str,
|
|
trait_path: &syn::Path,
|
|
) -> TokenStream {
|
|
if let syn::Data::Union(_) = &input.data {
|
|
let message = format!("Cannot derive {trait_name} for unions.");
|
|
return quote_spanned! {
|
|
input.span() => compile_error!(#message);
|
|
}
|
|
.into();
|
|
}
|
|
|
|
let ident = input.ident.clone();
|
|
let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
|
|
let mut where_clause = where_clause.cloned().unwrap_or_else(|| syn::WhereClause {
|
|
where_token: Default::default(),
|
|
predicates: Default::default(),
|
|
});
|
|
where_clause.predicates.push(
|
|
syn::parse2(quote! {
|
|
Self: 'static + Send + Sync + Clone + Eq + ::core::fmt::Debug + ::core::hash::Hash
|
|
})
|
|
.unwrap(),
|
|
);
|
|
quote! {
|
|
// To ensure alloc is available, but also prevent its name from clashing, we place the implementation inside an anonymous constant
|
|
const _: () = {
|
|
extern crate alloc;
|
|
|
|
impl #impl_generics #trait_path for #ident #ty_generics #where_clause {
|
|
fn dyn_clone(&self) -> alloc::boxed::Box<dyn #trait_path> {
|
|
alloc::boxed::Box::new(::core::clone::Clone::clone(self))
|
|
}
|
|
}
|
|
};
|
|
}
|
|
.into()
|
|
}
|