bevy/crates/bevy_ecs/macros/src/fetch.rs
Boxy e528b63e11 merge matches_archetype and matches_table (#4807)
# Objective

the code in these fns are always identical so stop having two functions

## Solution

make them the same function

---

## Changelog

change `matches_archetype` and `matches_table` to `fn matches_component_set(&self, &SparseArray<ComponentId, usize>) -> bool` then do extremely boring updating of all `FetchState` impls

## Migration Guide

- move logic of `matches_archetype` and `matches_table` into `matches_component_set` in any manual `FetchState` impls
2022-05-30 16:41:32 +00:00

426 lines
17 KiB
Rust

use proc_macro::TokenStream;
use proc_macro2::{Ident, Span};
use quote::{quote, ToTokens};
use syn::{
parse::{Parse, ParseStream},
parse_quote,
punctuated::Punctuated,
Attribute, Data, DataStruct, DeriveInput, Field, Fields,
};
use crate::bevy_ecs_path;
#[derive(Default)]
struct FetchStructAttributes {
pub is_mutable: bool,
pub derive_args: Punctuated<syn::NestedMeta, syn::token::Comma>,
}
static MUTABLE_ATTRIBUTE_NAME: &str = "mutable";
static DERIVE_ATTRIBUTE_NAME: &str = "derive";
mod field_attr_keywords {
syn::custom_keyword!(ignore);
}
pub static WORLD_QUERY_ATTRIBUTE_NAME: &str = "world_query";
pub fn derive_world_query_impl(ast: DeriveInput) -> TokenStream {
let visibility = ast.vis;
let mut fetch_struct_attributes = FetchStructAttributes::default();
for attr in &ast.attrs {
if !attr
.path
.get_ident()
.map_or(false, |ident| ident == WORLD_QUERY_ATTRIBUTE_NAME)
{
continue;
}
attr.parse_args_with(|input: ParseStream| {
let meta = input.parse_terminated::<syn::Meta, syn::token::Comma>(syn::Meta::parse)?;
for meta in meta {
let ident = meta.path().get_ident().unwrap_or_else(|| {
panic!(
"Unrecognized attribute: `{}`",
meta.path().to_token_stream()
)
});
if ident == MUTABLE_ATTRIBUTE_NAME {
if let syn::Meta::Path(_) = meta {
fetch_struct_attributes.is_mutable = true;
} else {
panic!(
"The `{}` attribute is expected to have no value or arguments",
MUTABLE_ATTRIBUTE_NAME
);
}
} else if ident == DERIVE_ATTRIBUTE_NAME {
if let syn::Meta::List(meta_list) = meta {
fetch_struct_attributes
.derive_args
.extend(meta_list.nested.iter().cloned());
} else {
panic!(
"Expected a structured list within the `{}` attribute",
DERIVE_ATTRIBUTE_NAME
);
}
} else {
panic!(
"Unrecognized attribute: `{}`",
meta.path().to_token_stream()
);
}
}
Ok(())
})
.unwrap_or_else(|_| panic!("Invalid `{}` attribute format", WORLD_QUERY_ATTRIBUTE_NAME));
}
let user_generics = ast.generics.clone();
let (user_impl_generics, user_ty_generics, user_where_clauses) = user_generics.split_for_impl();
let user_generics_with_world = {
let mut generics = ast.generics.clone();
generics.params.insert(0, parse_quote!('__w));
generics
};
let (user_impl_generics_with_world, user_ty_generics_with_world, user_where_clauses_with_world) =
user_generics_with_world.split_for_impl();
let struct_name = ast.ident.clone();
let item_struct_name = Ident::new(&format!("{}Item", struct_name), Span::call_site());
let read_only_item_struct_name = if fetch_struct_attributes.is_mutable {
Ident::new(&format!("{}ReadOnlyItem", struct_name), Span::call_site())
} else {
item_struct_name.clone()
};
let fetch_struct_name = Ident::new(&format!("{}Fetch", struct_name), Span::call_site());
let read_only_fetch_struct_name = if fetch_struct_attributes.is_mutable {
Ident::new(&format!("{}ReadOnlyFetch", struct_name), Span::call_site())
} else {
fetch_struct_name.clone()
};
let state_struct_name = Ident::new(&format!("{}State", struct_name), Span::call_site());
let fetch_type_alias = Ident::new("QueryFetch", Span::call_site());
let read_only_fetch_type_alias = Ident::new("ROQueryFetch", Span::call_site());
let item_type_alias = Ident::new("QueryItem", Span::call_site());
let read_only_item_type_alias = Ident::new("ROQueryItem", Span::call_site());
let fields = match &ast.data {
Data::Struct(DataStruct {
fields: Fields::Named(fields),
..
}) => &fields.named,
_ => panic!("Expected a struct with named fields"),
};
let mut ignored_field_attrs = Vec::new();
let mut ignored_field_visibilities = Vec::new();
let mut ignored_field_idents = Vec::new();
let mut ignored_field_types = Vec::new();
let mut field_attrs = Vec::new();
let mut field_visibilities = Vec::new();
let mut field_idents = Vec::new();
let mut field_types = Vec::new();
for field in fields.iter() {
let WorldQueryFieldInfo { is_ignored, attrs } = read_world_query_field_info(field);
let field_ident = field.ident.as_ref().unwrap().clone();
if is_ignored {
ignored_field_attrs.push(attrs);
ignored_field_visibilities.push(field.vis.clone());
ignored_field_idents.push(field_ident.clone());
ignored_field_types.push(field.ty.clone());
} else {
field_attrs.push(attrs);
field_visibilities.push(field.vis.clone());
field_idents.push(field_ident.clone());
field_types.push(field.ty.clone());
}
}
let derive_args = &fetch_struct_attributes.derive_args;
// `#[derive()]` is valid syntax
let derive_macro_call = quote! { #[derive(#derive_args)] };
let path = bevy_ecs_path();
let impl_fetch = |is_readonly: bool, fetch_struct_name: Ident, item_struct_name: Ident| {
let fetch_type_alias = if is_readonly {
&read_only_fetch_type_alias
} else {
&fetch_type_alias
};
let item_type_alias = if is_readonly {
&read_only_item_type_alias
} else {
&item_type_alias
};
quote! {
#derive_macro_call
#[automatically_derived]
#visibility struct #item_struct_name #user_impl_generics_with_world #user_where_clauses_with_world {
#(#(#field_attrs)* #field_visibilities #field_idents: #path::query::#item_type_alias<'__w, #field_types>,)*
#(#(#ignored_field_attrs)* #ignored_field_visibilities #ignored_field_idents: #ignored_field_types,)*
}
#[doc(hidden)]
#visibility struct #fetch_struct_name #user_impl_generics_with_world #user_where_clauses_with_world {
#(#field_idents: #path::query::#fetch_type_alias::<'__w, #field_types>,)*
#(#ignored_field_idents: #ignored_field_types,)*
}
impl #user_impl_generics_with_world #path::query::Fetch<'__w>
for #fetch_struct_name #user_ty_generics_with_world #user_where_clauses_with_world {
type Item = #item_struct_name #user_ty_generics_with_world;
type State = #state_struct_name #user_ty_generics;
unsafe fn init(_world: &'__w #path::world::World, state: &Self::State, _last_change_tick: u32, _change_tick: u32) -> Self {
Self {
#(#field_idents:
#path::query::#fetch_type_alias::<'__w, #field_types>::init(
_world,
&state.#field_idents,
_last_change_tick,
_change_tick
),
)*
#(#ignored_field_idents: Default::default(),)*
}
}
const IS_DENSE: bool = true #(&& #path::query::#fetch_type_alias::<'__w, #field_types>::IS_DENSE)*;
const IS_ARCHETYPAL: bool = true #(&& #path::query::#fetch_type_alias::<'__w, #field_types>::IS_ARCHETYPAL)*;
/// SAFETY: we call `set_archetype` for each member that implements `Fetch`
#[inline]
unsafe fn set_archetype(
&mut self,
_state: &Self::State,
_archetype: &'__w #path::archetype::Archetype,
_tables: &'__w #path::storage::Tables
) {
#(self.#field_idents.set_archetype(&_state.#field_idents, _archetype, _tables);)*
}
/// SAFETY: we call `set_table` for each member that implements `Fetch`
#[inline]
unsafe fn set_table(&mut self, _state: &Self::State, _table: &'__w #path::storage::Table) {
#(self.#field_idents.set_table(&_state.#field_idents, _table);)*
}
/// SAFETY: we call `table_fetch` for each member that implements `Fetch`.
#[inline]
unsafe fn table_fetch(&mut self, _table_row: usize) -> Self::Item {
Self::Item {
#(#field_idents: self.#field_idents.table_fetch(_table_row),)*
#(#ignored_field_idents: Default::default(),)*
}
}
/// SAFETY: we call `archetype_fetch` for each member that implements `Fetch`.
#[inline]
unsafe fn archetype_fetch(&mut self, _archetype_index: usize) -> Self::Item {
Self::Item {
#(#field_idents: self.#field_idents.archetype_fetch(_archetype_index),)*
#(#ignored_field_idents: Default::default(),)*
}
}
#[allow(unused_variables)]
#[inline]
unsafe fn table_filter_fetch(&mut self, _table_row: usize) -> bool {
true #(&& self.#field_idents.table_filter_fetch(_table_row))*
}
#[allow(unused_variables)]
#[inline]
unsafe fn archetype_filter_fetch(&mut self, _archetype_index: usize) -> bool {
true #(&& self.#field_idents.archetype_filter_fetch(_archetype_index))*
}
}
}
};
let fetch_impl = impl_fetch(false, fetch_struct_name.clone(), item_struct_name.clone());
let state_impl = quote! {
#[doc(hidden)]
#visibility struct #state_struct_name #user_impl_generics #user_where_clauses {
#(#field_idents: <#field_types as #path::query::WorldQuery>::State,)*
#(#ignored_field_idents: #ignored_field_types,)*
}
// SAFETY: `update_component_access` and `update_archetype_component_access` are called for each item in the struct
unsafe impl #user_impl_generics #path::query::FetchState for #state_struct_name #user_ty_generics #user_where_clauses {
fn init(world: &mut #path::world::World) -> Self {
#state_struct_name {
#(#field_idents: <<#field_types as #path::query::WorldQuery>::State as #path::query::FetchState>::init(world),)*
#(#ignored_field_idents: Default::default(),)*
}
}
fn update_component_access(&self, _access: &mut #path::query::FilteredAccess<#path::component::ComponentId>) {
#(self.#field_idents.update_component_access(_access);)*
}
fn update_archetype_component_access(&self, _archetype: &#path::archetype::Archetype, _access: &mut #path::query::Access<#path::archetype::ArchetypeComponentId>) {
#(self.#field_idents.update_archetype_component_access(_archetype, _access);)*
}
fn matches_component_set(&self, _set_contains_id: &impl Fn(#path::component::ComponentId) -> bool) -> bool {
true #(&& self.#field_idents.matches_component_set(_set_contains_id))*
}
}
};
let read_only_fetch_impl = if fetch_struct_attributes.is_mutable {
impl_fetch(
true,
read_only_fetch_struct_name.clone(),
read_only_item_struct_name,
)
} else {
quote! {}
};
let read_only_asserts = if fetch_struct_attributes.is_mutable {
quote! {
// Double-check that the data fetched by `ROQueryFetch` is read-only.
// This is technically unnecessary as `<_ as WorldQueryGats<'world>>::ReadOnlyFetch: ReadOnlyFetch`
// but to protect against future mistakes we assert the assoc type implements `ReadOnlyFetch` anyway
#( assert_readonly::<#path::query::ROQueryFetch<'__w, #field_types>>(); )*
}
} else {
quote! {
// Statically checks that the safety guarantee of `ReadOnlyFetch` for `$fetch_struct_name` actually holds true.
// We need this to make sure that we don't compile `ReadOnlyFetch` if our struct contains nested `WorldQuery`
// members that don't implement it. I.e.:
// ```
// #[derive(WorldQuery)]
// pub struct Foo { a: &'static mut MyComponent }
// ```
#( assert_readonly::<#path::query::QueryFetch<'__w, #field_types>>(); )*
}
};
let tokens = TokenStream::from(quote! {
#fetch_impl
#state_impl
#read_only_fetch_impl
impl #user_impl_generics #path::query::WorldQuery for #struct_name #user_ty_generics #user_where_clauses {
type State = #state_struct_name #user_ty_generics;
fn shrink<'__wlong: '__wshort, '__wshort>(item: #path::query::#item_type_alias<'__wlong, Self>)
-> #path::query::#item_type_alias<'__wshort, Self> {
#item_struct_name {
#(
#field_idents : < #field_types as #path::query::WorldQuery> :: shrink( item.#field_idents ),
)*
#(
#ignored_field_idents: item.#ignored_field_idents,
)*
}
}
}
impl #user_impl_generics_with_world #path::query::WorldQueryGats<'__w> for #struct_name #user_ty_generics #user_where_clauses {
type Fetch = #fetch_struct_name #user_ty_generics_with_world;
type ReadOnlyFetch = #read_only_fetch_struct_name #user_ty_generics_with_world;
type _State = #state_struct_name #user_ty_generics;
}
/// SAFETY: each item in the struct is read only
unsafe impl #user_impl_generics_with_world #path::query::ReadOnlyFetch
for #read_only_fetch_struct_name #user_ty_generics_with_world #user_where_clauses_with_world {}
#[allow(dead_code)]
const _: () = {
fn assert_readonly<T>()
where
T: #path::query::ReadOnlyFetch,
{
}
// We generate a readonly assertion for every struct member.
fn assert_all #user_impl_generics_with_world () #user_where_clauses_with_world {
#read_only_asserts
}
};
// The original struct will most likely be left unused. As we don't want our users having
// to specify `#[allow(dead_code)]` for their custom queries, we are using this cursed
// workaround.
#[allow(dead_code)]
const _: () = {
fn dead_code_workaround #user_impl_generics (q: #struct_name #user_ty_generics) #user_where_clauses {
#(q.#field_idents;)*
#(q.#ignored_field_idents;)*
}
};
});
tokens
}
struct WorldQueryFieldInfo {
/// Has `#[fetch(ignore)]` or `#[filter_fetch(ignore)]` attribute.
is_ignored: bool,
/// All field attributes except for `world_query` ones.
attrs: Vec<Attribute>,
}
fn read_world_query_field_info(field: &Field) -> WorldQueryFieldInfo {
let is_ignored = field
.attrs
.iter()
.find(|attr| {
attr.path
.get_ident()
.map_or(false, |ident| ident == WORLD_QUERY_ATTRIBUTE_NAME)
})
.map_or(false, |attr| {
let mut is_ignored = false;
attr.parse_args_with(|input: ParseStream| {
if input
.parse::<Option<field_attr_keywords::ignore>>()?
.is_some()
{
is_ignored = true;
}
Ok(())
})
.unwrap_or_else(|_| {
panic!("Invalid `{}` attribute format", WORLD_QUERY_ATTRIBUTE_NAME)
});
is_ignored
});
let attrs = field
.attrs
.iter()
.filter(|attr| {
attr.path
.get_ident()
.map_or(true, |ident| ident != WORLD_QUERY_ATTRIBUTE_NAME)
})
.cloned()
.collect();
WorldQueryFieldInfo { is_ignored, attrs }
}