760d0a3100
# Objective - Minor consistency improvement in proc macro code. - Remove `get_path_direct` since it was only used once anyways and doesn't add much. ## Solution - Possibly a minor performance improvement since the `Cargo.toml` wont be parsed as often. ## Testing - I don't think it breaks anything. - This is my first time working on bevy itself. Is there a script to do a quick verify of my pr? ## Other PR Similar to #7536 but has no extra dependencies. Co-authored-by: François Mockers <mockersf@gmail.com>
97 lines
4.5 KiB
Rust
97 lines
4.5 KiB
Rust
use bevy_macro_utils::{
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fq_std::{FQClone, FQOption, FQResult},
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BevyManifest,
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};
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use proc_macro::TokenStream;
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use quote::quote;
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use syn::{parse::Parse, parse_macro_input, Attribute, ItemTrait, Token};
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pub(crate) struct TraitInfo {
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item_trait: ItemTrait,
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}
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impl Parse for TraitInfo {
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fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
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let attrs = input.call(Attribute::parse_outer)?;
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let lookahead = input.lookahead1();
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if lookahead.peek(Token![pub]) || lookahead.peek(Token![trait]) {
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let mut item_trait: ItemTrait = input.parse()?;
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item_trait.attrs = attrs;
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Ok(TraitInfo { item_trait })
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} else {
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Err(lookahead.error())
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}
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}
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}
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/// A trait attribute macro that allows a reflected type to be downcast to a trait object.
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///
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/// This generates a struct that takes the form `ReflectMyTrait`. An instance of this struct can then be
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/// used to perform the conversion.
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pub(crate) fn reflect_trait(_args: &TokenStream, input: TokenStream) -> TokenStream {
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let trait_info = parse_macro_input!(input as TraitInfo);
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let item_trait = &trait_info.item_trait;
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let trait_ident = &item_trait.ident;
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let trait_vis = &item_trait.vis;
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let reflect_trait_ident = crate::ident::get_reflect_ident(&item_trait.ident.to_string());
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let bevy_reflect_path = BevyManifest::shared().get_path("bevy_reflect");
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let struct_doc = format!(
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" A type generated by the #[reflect_trait] macro for the `{trait_ident}` trait.\n\n This allows casting from `dyn Reflect` to `dyn {trait_ident}`.",
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);
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let get_doc = format!(
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" Downcast a `&dyn Reflect` type to `&dyn {trait_ident}`.\n\n If the type cannot be downcast, `None` is returned.",
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);
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let get_mut_doc = format!(
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" Downcast a `&mut dyn Reflect` type to `&mut dyn {trait_ident}`.\n\n If the type cannot be downcast, `None` is returned.",
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);
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let get_box_doc = format!(
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" Downcast a `Box<dyn Reflect>` type to `Box<dyn {trait_ident}>`.\n\n If the type cannot be downcast, this will return `Err(Box<dyn Reflect>)`.",
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);
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TokenStream::from(quote! {
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#item_trait
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#[doc = #struct_doc]
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#[derive(#FQClone)]
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#trait_vis struct #reflect_trait_ident {
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get_func: fn(&dyn #bevy_reflect_path::Reflect) -> #FQOption<&dyn #trait_ident>,
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get_mut_func: fn(&mut dyn #bevy_reflect_path::Reflect) -> #FQOption<&mut dyn #trait_ident>,
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get_boxed_func: fn(#bevy_reflect_path::__macro_exports::alloc_utils::Box<dyn #bevy_reflect_path::Reflect>) -> #FQResult<#bevy_reflect_path::__macro_exports::alloc_utils::Box<dyn #trait_ident>, #bevy_reflect_path::__macro_exports::alloc_utils::Box<dyn #bevy_reflect_path::Reflect>>,
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}
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impl #reflect_trait_ident {
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#[doc = #get_doc]
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pub fn get<'a>(&self, reflect_value: &'a dyn #bevy_reflect_path::Reflect) -> #FQOption<&'a dyn #trait_ident> {
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(self.get_func)(reflect_value)
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}
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#[doc = #get_mut_doc]
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pub fn get_mut<'a>(&self, reflect_value: &'a mut dyn #bevy_reflect_path::Reflect) -> #FQOption<&'a mut dyn #trait_ident> {
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(self.get_mut_func)(reflect_value)
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}
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#[doc = #get_box_doc]
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pub fn get_boxed(&self, reflect_value: #bevy_reflect_path::__macro_exports::alloc_utils::Box<dyn #bevy_reflect_path::Reflect>) -> #FQResult<#bevy_reflect_path::__macro_exports::alloc_utils::Box<dyn #trait_ident>, #bevy_reflect_path::__macro_exports::alloc_utils::Box<dyn #bevy_reflect_path::Reflect>> {
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(self.get_boxed_func)(reflect_value)
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}
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}
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impl<T: #trait_ident + #bevy_reflect_path::Reflect> #bevy_reflect_path::FromType<T> for #reflect_trait_ident {
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fn from_type() -> Self {
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Self {
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get_func: |reflect_value| {
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<dyn #bevy_reflect_path::Reflect>::downcast_ref::<T>(reflect_value).map(|value| value as &dyn #trait_ident)
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},
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get_mut_func: |reflect_value| {
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<dyn #bevy_reflect_path::Reflect>::downcast_mut::<T>(reflect_value).map(|value| value as &mut dyn #trait_ident)
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},
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get_boxed_func: |reflect_value| {
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<dyn #bevy_reflect_path::Reflect>::downcast::<T>(reflect_value).map(|value| value as #bevy_reflect_path::__macro_exports::alloc_utils::Box<dyn #trait_ident>)
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}
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}
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}
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}
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})
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}
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