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Port hecs derive macro improvements (#761)
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* Port derive macro changes from hecs

* Emit more info on duplicate components in archetype creation
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@Veykril
Veykril committed Nov 6, 2020
1 parent 26be22e commit fb7c651
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Showing 3 changed files with 232 additions and 66 deletions.
240 changes: 179 additions & 61 deletions crates/bevy_ecs/hecs/macros/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,132 +16,250 @@

extern crate proc_macro;

use std::borrow::Cow;

use proc_macro::TokenStream;
use proc_macro2::Span;
use proc_macro2::{Span, TokenStream as TokenStream2};
use proc_macro_crate::crate_name;
use quote::quote;
use syn::{parse_macro_input, DeriveInput, Ident, Index, Lifetime, Path};
use syn::{parse_macro_input, DeriveInput, Error, Ident, Index, Lifetime, Path, Result};

/// Implement `Bundle` for a monomorphic struct
///
/// Using derived `Bundle` impls improves spawn performance and can be convenient when combined with
/// other derives like `serde::Deserialize`.
#[allow(clippy::cognitive_complexity)]
#[proc_macro_derive(Bundle)]
pub fn derive_bundle(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
if !input.generics.params.is_empty() {
return TokenStream::from(
quote! { compile_error!("derive(Bundle) does not support generics"); },
);
match derive_bundle_(input) {
Ok(ts) => ts,
Err(e) => e.to_compile_error(),
}
.into()
}

#[allow(clippy::cognitive_complexity)]
fn derive_bundle_(input: DeriveInput) -> Result<TokenStream2> {
let ident = input.ident;
let data = match input.data {
syn::Data::Struct(s) => s,
_ => {
return TokenStream::from(
quote! { compile_error!("derive(Bundle) only supports structs"); },
)
return Err(Error::new_spanned(
ident,
"derive(Bundle) does not support enums or unions",
))
}
};
let ident = input.ident;
let (tys, fields) = struct_fields(&data.fields);
let (tys, field_members) = struct_fields(&data.fields);
let path_str = if crate_name("bevy").is_ok() {
"bevy::ecs"
} else if crate_name("bevy_ecs").is_ok() {
"bevy_ecs"
} else {
"bevy_hecs"
};
let crate_path: Path = syn::parse(path_str.parse::<TokenStream>().unwrap()).unwrap();
let field_idents = member_as_idents(&field_members);
let generics = add_additional_bounds_to_generic_params(&crate_path, input.generics);

let path: Path = syn::parse(path_str.parse::<TokenStream>().unwrap()).unwrap();
let dyn_bundle_code =
gen_dynamic_bundle_impl(&crate_path, &ident, &generics, &field_members, &tys);
let bundle_code = if tys.is_empty() {
gen_unit_struct_bundle_impl(&crate_path, ident, &generics)
} else {
gen_bundle_impl(
&crate_path,
&ident,
&generics,
&field_members,
&field_idents,
&tys,
)
};
let mut ts = dyn_bundle_code;
ts.extend(bundle_code);
Ok(ts)
}

let n = tys.len();
let code = quote! {
impl #path::DynamicBundle for #ident {
fn with_ids<T>(&self, f: impl FnOnce(&[std::any::TypeId]) -> T) -> T {
Self::with_static_ids(f)
fn gen_dynamic_bundle_impl(
crate_path: &syn::Path,
ident: &syn::Ident,
generics: &syn::Generics,
field_members: &[syn::Member],
tys: &[&syn::Type],
) -> TokenStream2 {
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
quote! {
impl #impl_generics ::#crate_path::DynamicBundle for #ident #ty_generics #where_clause {
fn with_ids<__hecs__T>(&self, f: impl ::std::ops::FnOnce(&[::std::any::TypeId]) -> __hecs__T) -> __hecs__T {
<Self as ::#crate_path::Bundle>::with_static_ids(f)
}

fn type_info(&self) -> Vec<#path::TypeInfo> {
Self::static_type_info()
fn type_info(&self) -> ::std::vec::Vec<::#crate_path::TypeInfo> {
<Self as ::#crate_path::Bundle>::static_type_info()
}

unsafe fn put(mut self, mut f: impl FnMut(*mut u8, std::any::TypeId, usize) -> bool) {
#[allow(clippy::forget_copy)]
unsafe fn put(mut self, mut f: impl ::std::ops::FnMut(*mut u8, ::std::any::TypeId, usize) -> bool) {
#(
if f((&mut self.#fields as *mut #tys).cast::<u8>(), std::any::TypeId::of::<#tys>(), std::mem::size_of::<#tys>()) {
if f((&mut self.#field_members as *mut #tys).cast::<u8>(), ::std::any::TypeId::of::<#tys>(), ::std::mem::size_of::<#tys>()) {
#[allow(clippy::forget_copy)]
std::mem::forget(self.#fields);
::std::mem::forget(self.#field_members);
}
)*
}
}
}
}

impl #path::Bundle for #ident {
fn with_static_ids<T>(f: impl FnOnce(&[std::any::TypeId]) -> T) -> T {
use std::any::TypeId;
use std::mem;

#path::lazy_static::lazy_static! {
static ref ELEMENTS: [TypeId; #n] = {
let mut dedup = #path::bevy_utils::HashSet::default();
for &(ty, name) in [#((std::any::TypeId::of::<#tys>(), std::any::type_name::<#tys>())),*].iter() {
if !dedup.insert(ty) {
panic!("{} has multiple {} fields; each type must occur at most once!", stringify!(#ident), name);
}
}

let mut tys = [#((mem::align_of::<#tys>(), TypeId::of::<#tys>())),*];
tys.sort_unstable_by(|x, y| x.0.cmp(&y.0).reverse().then(x.1.cmp(&y.1)));
let mut ids = [TypeId::of::<()>(); #n];
for (id, info) in ids.iter_mut().zip(tys.iter()) {
*id = info.1;
}
ids
};
}

f(&*ELEMENTS)
fn gen_bundle_impl(
crate_path: &syn::Path,
ident: &syn::Ident,
generics: &syn::Generics,
field_members: &[syn::Member],
field_idents: &[Cow<syn::Ident>],
tys: &[&syn::Type],
) -> TokenStream2 {
let num_tys = tys.len();
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let with_static_ids_inner = quote! {
{
let mut tys = [#((::std::mem::align_of::<#tys>(), ::std::any::TypeId::of::<#tys>())),*];
tys.sort_unstable_by(|x, y| {
::std::cmp::Ord::cmp(&x.0, &y.0)
.reverse()
.then(::std::cmp::Ord::cmp(&x.1, &y.1))
});
let mut ids = [::std::any::TypeId::of::<()>(); #num_tys];
for (id, info) in ::std::iter::Iterator::zip(ids.iter_mut(), tys.iter()) {
*id = info.1;
}
ids
}
};
let with_static_ids_body = if generics.params.is_empty() {
quote! {
::#crate_path::lazy_static::lazy_static! {
static ref ELEMENTS: [::std::any::TypeId; #num_tys] = {
#with_static_ids_inner
};
}
f(&*ELEMENTS)
}
} else {
quote! {
f(&#with_static_ids_inner)
}
};
quote! {
impl #impl_generics ::#crate_path::Bundle for #ident #ty_generics #where_clause {
#[allow(non_camel_case_types)]
fn with_static_ids<__hecs__T>(f: impl ::std::ops::FnOnce(&[::std::any::TypeId]) -> __hecs__T) -> __hecs__T {
#with_static_ids_body
}

fn static_type_info() -> Vec<#path::TypeInfo> {
let mut info = vec![#(#path::TypeInfo::of::<#tys>()),*];
fn static_type_info() -> ::std::vec::Vec<::#crate_path::TypeInfo> {
let mut info = ::std::vec![#(::#crate_path::TypeInfo::of::<#tys>()),*];
info.sort_unstable();
info
}

unsafe fn get(
mut f: impl FnMut(std::any::TypeId, usize) -> Option<std::ptr::NonNull<u8>>,
) -> Result<Self, #path::MissingComponent> {
mut f: impl ::std::ops::FnMut(::std::any::TypeId, usize) -> ::std::option::Option<::std::ptr::NonNull<u8>>,
) -> ::std::result::Result<Self, ::#crate_path::MissingComponent> {
#(
let #fields = f(std::any::TypeId::of::<#tys>(), std::mem::size_of::<#tys>())
.ok_or_else(#path::MissingComponent::new::<#tys>)?
let #field_idents = f(::std::any::TypeId::of::<#tys>(), ::std::mem::size_of::<#tys>())
.ok_or_else(::#crate_path::MissingComponent::new::<#tys>)?
.cast::<#tys>()
.as_ptr();
.as_ptr();
)*
Ok(Self { #( #fields: #fields.read(), )* })
::std::result::Result::Ok(Self { #( #field_members: #field_idents.read(), )* })
}
}
};
TokenStream::from(code)
}
}

fn struct_fields(fields: &syn::Fields) -> (Vec<&syn::Type>, Vec<syn::Ident>) {
// no reason to generate a static for unit structs
fn gen_unit_struct_bundle_impl(
crate_path: &syn::Path,
ident: syn::Ident,
generics: &syn::Generics,
) -> TokenStream2 {
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
quote! {
impl #impl_generics ::#crate_path::Bundle for #ident #ty_generics #where_clause {
#[allow(non_camel_case_types)]
fn with_static_ids<__hecs__T>(f: impl ::std::ops::FnOnce(&[::std::any::TypeId]) -> __hecs__T) -> __hecs__T { f(&[]) }
fn static_type_info() -> ::std::vec::Vec<::#crate_path::TypeInfo> { ::std::vec::Vec::new() }

unsafe fn get(
f: impl ::std::ops::FnMut(::std::any::TypeId, usize) -> ::std::option::Option<::std::ptr::NonNull<u8>>,
) -> Result<Self, ::#crate_path::MissingComponent> {
Ok(Self {/* for some reason this works for all unit struct variations */})
}
}
}
}

fn make_component_trait_bound(crate_path: &syn::Path) -> syn::TraitBound {
syn::TraitBound {
paren_token: None,
modifier: syn::TraitBoundModifier::None,
lifetimes: None,
path: syn::parse_quote!(::#crate_path::Component),
}
}

fn add_additional_bounds_to_generic_params(
crate_path: &syn::Path,
mut generics: syn::Generics,
) -> syn::Generics {
generics.type_params_mut().for_each(|tp| {
tp.bounds
.push(syn::TypeParamBound::Trait(make_component_trait_bound(
crate_path,
)))
});
generics
}

fn struct_fields(fields: &syn::Fields) -> (Vec<&syn::Type>, Vec<syn::Member>) {
match fields {
syn::Fields::Named(ref fields) => fields
.named
.iter()
.map(|f| (&f.ty, f.ident.clone().unwrap()))
.map(|f| (&f.ty, syn::Member::Named(f.ident.clone().unwrap())))
.unzip(),
syn::Fields::Unnamed(ref fields) => fields
.unnamed
.iter()
.enumerate()
.map(|(i, f)| (&f.ty, syn::Ident::new(&i.to_string(), Span::call_site())))
.map(|(i, f)| {
(
&f.ty,
syn::Member::Unnamed(syn::Index {
index: i as u32,
span: Span::call_site(),
}),
)
})
.unzip(),
syn::Fields::Unit => (Vec::new(), Vec::new()),
}
}

fn member_as_idents(members: &[syn::Member]) -> Vec<Cow<'_, syn::Ident>> {
members
.iter()
.map(|member| match member {
syn::Member::Named(ident) => Cow::Borrowed(ident),
&syn::Member::Unnamed(syn::Index { index, span }) => {
Cow::Owned(syn::Ident::new(&format!("tuple_field_{}", index), span))
}
})
.collect()
}

fn get_idents(fmt_string: fn(usize) -> String, count: usize) -> Vec<Ident> {
(0..count)
.map(|i| Ident::new(&fmt_string(i), Span::call_site()))
Expand Down
27 changes: 23 additions & 4 deletions crates/bevy_ecs/hecs/src/archetype.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -51,17 +51,32 @@ pub struct Archetype {
}

impl Archetype {
fn assert_type_info(types: &[TypeInfo]) {
types.windows(2).for_each(|x| match x[0].cmp(&x[1]) {
core::cmp::Ordering::Less => (),
#[cfg(debug_assertions)]
core::cmp::Ordering::Equal => panic!(
"attempted to allocate entity with duplicate {} components; \
each type must occur at most once!",
x[0].type_name
),
#[cfg(not(debug_assertions))]
core::cmp::Ordering::Equal => panic!(
"attempted to allocate entity with duplicate components; \
each type must occur at most once!"
),
core::cmp::Ordering::Greater => panic!("type info is unsorted"),
});
}

#[allow(missing_docs)]
pub fn new(types: Vec<TypeInfo>) -> Self {
Self::with_grow(types, 64)
}

#[allow(missing_docs)]
pub fn with_grow(types: Vec<TypeInfo>, grow_size: usize) -> Self {
debug_assert!(
types.windows(2).all(|x| x[0] < x[1]),
"type info unsorted or contains duplicates"
);
Self::assert_type_info(&types);
let mut state = HashMap::with_capacity_and_hasher(types.len(), Default::default());
for ty in &types {
state.insert(ty.id, TypeState::new());
Expand Down Expand Up @@ -488,6 +503,8 @@ pub struct TypeInfo {
id: TypeId,
layout: Layout,
drop: unsafe fn(*mut u8),
#[cfg(debug_assertions)]
type_name: &'static str,
}

impl TypeInfo {
Expand All @@ -501,6 +518,8 @@ impl TypeInfo {
id: TypeId::of::<T>(),
layout: Layout::new::<T>(),
drop: drop_ptr::<T>,
#[cfg(debug_assertions)]
type_name: core::any::type_name::<T>(),
}
}

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