bevy/crates/bevy_macro_utils/src/lib.rs
danieleades d8974e7c3d small and mostly pointless refactoring (#2934)
What is says on the tin.

This has got more to do with making `clippy` slightly more *quiet* than it does with changing anything that might greatly impact readability or performance.

that said, deriving `Default` for a couple of structs is a nice easy win
2022-02-13 22:33:55 +00:00

97 lines
3 KiB
Rust

extern crate proc_macro;
mod attrs;
mod shape;
mod symbol;
pub use attrs::*;
pub use shape::*;
pub use symbol::*;
use cargo_manifest::{DepsSet, Manifest};
use proc_macro::TokenStream;
use quote::quote;
use std::{env, path::PathBuf};
pub struct BevyManifest {
manifest: Manifest,
}
impl Default for BevyManifest {
fn default() -> Self {
Self {
manifest: env::var_os("CARGO_MANIFEST_DIR")
.map(PathBuf::from)
.map(|mut path| {
path.push("Cargo.toml");
Manifest::from_path(path).unwrap()
})
.unwrap(),
}
}
}
impl BevyManifest {
pub fn maybe_get_path(&self, name: &str) -> Option<syn::Path> {
const BEVY: &str = "bevy";
const BEVY_INTERNAL: &str = "bevy_internal";
let find_in_deps = |deps: &DepsSet| -> Option<syn::Path> {
let package = if let Some(dep) = deps.get(name) {
return Some(Self::parse_str(dep.package().unwrap_or(name)));
} else if let Some(dep) = deps.get(BEVY) {
dep.package().unwrap_or(BEVY)
} else if let Some(dep) = deps.get(BEVY_INTERNAL) {
dep.package().unwrap_or(BEVY_INTERNAL)
} else {
return None;
};
let mut path = Self::parse_str::<syn::Path>(package);
if let Some(module) = name.strip_prefix("bevy_") {
path.segments.push(Self::parse_str(module));
}
Some(path)
};
let deps = self.manifest.dependencies.as_ref();
let deps_dev = self.manifest.dev_dependencies.as_ref();
deps.and_then(find_in_deps)
.or_else(|| deps_dev.and_then(find_in_deps))
}
pub fn get_path(&self, name: &str) -> syn::Path {
self.maybe_get_path(name)
.unwrap_or_else(|| Self::parse_str(name))
}
pub fn parse_str<T: syn::parse::Parse>(path: &str) -> T {
syn::parse(path.parse::<TokenStream>().unwrap()).unwrap()
}
}
/// Derive a label trait
///
/// # Args
///
/// - `input`: The [`syn::DeriveInput`] for struct that is deriving the label trait
/// - `trait_path`: The path [`syn::Path`] to the label trait
pub fn derive_label(input: syn::DeriveInput, trait_path: &syn::Path) -> TokenStream {
let ident = input.ident;
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: Eq + ::std::fmt::Debug + ::std::hash::Hash + Clone + Send + Sync + 'static }).unwrap());
(quote! {
impl #impl_generics #trait_path for #ident #ty_generics #where_clause {
fn dyn_clone(&self) -> std::boxed::Box<dyn #trait_path> {
std::boxed::Box::new(std::clone::Clone::clone(self))
}
}
})
.into()
}