mirror of
https://github.com/bevyengine/bevy
synced 2024-11-10 07:04:33 +00:00
bevy_reflect: enum_utility cleanup (#13424)
# Objective The `enum_utility` module contains the `get_variant_constructors` function, which is used to generate token streams for constructing enums. It's used for the `FromReflect::from_reflect` implementation and the `Reflect::try_apply` implementation. Due to the complexity of enums, this function is understandably a little messy and difficult to extend. ## Solution Clean up the `enum_utility` module. Now "clean" is a bit subjective. I believe my solution is "cleaner" in that the logic to generate the tokens are strictly coupled with the intended usage. Because of this, `try_apply` is also no longer strictly coupled with `from_reflect`. This makes it easier to extend with new functionality, which is something I'm doing in a future unrelated PR that I have based off this one. ## Testing There shouldn't be any testing required other than ensuring that the project still builds and that CI passes.
This commit is contained in:
Gino Valente
GitHub
parent
c4cedb12c8
commit
faf003fc9d
3 changed files with 256 additions and 109 deletions
|
|
@ -1,122 +1,266 @@
|
|||
use crate::derive_data::StructField;
|
||||
use crate::field_attributes::DefaultBehavior;
|
||||
use crate::{
|
||||
derive_data::{EnumVariantFields, ReflectEnum},
|
||||
utility::ident_or_index,
|
||||
};
|
||||
use crate::{derive_data::ReflectEnum, utility::ident_or_index};
|
||||
use bevy_macro_utils::fq_std::{FQDefault, FQOption};
|
||||
use proc_macro2::Ident;
|
||||
use quote::{quote, ToTokens};
|
||||
use syn::Member;
|
||||
use proc_macro2::{Ident, TokenStream};
|
||||
use quote::{format_ident, quote};
|
||||
|
||||
/// Contains all data needed to construct all variants within an enum.
|
||||
pub(crate) struct EnumVariantConstructors {
|
||||
pub(crate) struct EnumVariantOutputData {
|
||||
/// The names of each variant as a string.
|
||||
///
|
||||
/// For example, `Some` and `None` for the `Option` enum.
|
||||
pub variant_names: Vec<String>,
|
||||
/// The stream of tokens that will construct each variant.
|
||||
pub variant_constructors: Vec<proc_macro2::TokenStream>,
|
||||
/// The constructor portion of each variant.
|
||||
///
|
||||
/// For example, `Option::Some { 0: value }` and `Option::None {}` for the `Option` enum.
|
||||
pub variant_constructors: Vec<TokenStream>,
|
||||
}
|
||||
|
||||
/// Gets the constructors for all variants in the given enum.
|
||||
pub(crate) fn get_variant_constructors(
|
||||
reflect_enum: &ReflectEnum,
|
||||
ref_value: &Ident,
|
||||
return_apply_error: bool,
|
||||
) -> EnumVariantConstructors {
|
||||
let bevy_reflect_path = reflect_enum.meta().bevy_reflect_path();
|
||||
let variant_count = reflect_enum.variants().len();
|
||||
let mut variant_names = Vec::with_capacity(variant_count);
|
||||
let mut variant_constructors = Vec::with_capacity(variant_count);
|
||||
#[derive(Copy, Clone)]
|
||||
pub(crate) struct VariantField<'a, 'b> {
|
||||
/// The alias for the field.
|
||||
///
|
||||
/// This should be used whenever the field needs to be referenced in a token stream.
|
||||
pub alias: &'a Ident,
|
||||
/// The name of the variant that contains the field.
|
||||
pub variant_name: &'a str,
|
||||
/// The field data.
|
||||
pub field: &'a StructField<'b>,
|
||||
}
|
||||
|
||||
for variant in reflect_enum.variants() {
|
||||
let ident = &variant.data.ident;
|
||||
let name = ident.to_string();
|
||||
let variant_constructor = reflect_enum.get_unit(ident);
|
||||
/// Trait used to control how enum variants are built.
|
||||
pub(crate) trait VariantBuilder: Sized {
|
||||
/// Returns the enum data.
|
||||
fn reflect_enum(&self) -> &ReflectEnum;
|
||||
|
||||
let fields: &[StructField] = match &variant.fields {
|
||||
EnumVariantFields::Unit => &[],
|
||||
EnumVariantFields::Named(fields) | EnumVariantFields::Unnamed(fields) => {
|
||||
fields.as_slice()
|
||||
/// Returns a token stream that accesses a field of a variant as an `Option<dyn Reflect>`.
|
||||
///
|
||||
/// The default implementation of this method will return a token stream
|
||||
/// which gets the field dynamically so as to support `dyn Enum`.
|
||||
///
|
||||
/// # Parameters
|
||||
/// * `this`: The identifier of the enum
|
||||
/// * `field`: The field to access
|
||||
fn access_field(&self, this: &Ident, field: VariantField) -> TokenStream {
|
||||
match &field.field.data.ident {
|
||||
Some(field_ident) => {
|
||||
let name = field_ident.to_string();
|
||||
quote!(#this.field(#name))
|
||||
}
|
||||
};
|
||||
let mut reflect_index: usize = 0;
|
||||
let constructor_fields = fields.iter().enumerate().map(|(declare_index, field)| {
|
||||
let field_ident = ident_or_index(field.data.ident.as_ref(), declare_index);
|
||||
let field_ty = &field.data.ty;
|
||||
|
||||
let field_value = if field.attrs.ignore.is_ignored() {
|
||||
match &field.attrs.default {
|
||||
DefaultBehavior::Func(path) => quote! { #path() },
|
||||
_ => quote! { #FQDefault::default() }
|
||||
}
|
||||
} else {
|
||||
let field_accessor = match &field.data.ident {
|
||||
Some(ident) => {
|
||||
let name = ident.to_string();
|
||||
quote!(#ref_value.field(#name))
|
||||
}
|
||||
None => quote!(#ref_value.field_at(#reflect_index)),
|
||||
};
|
||||
reflect_index += 1;
|
||||
|
||||
let (resolve_error, resolve_missing) = if return_apply_error {
|
||||
let field_ref_str = match &field_ident {
|
||||
Member::Named(ident) => format!("{ident}"),
|
||||
Member::Unnamed(index) => format!(".{}", index.index)
|
||||
};
|
||||
let ty = field.data.ty.to_token_stream();
|
||||
|
||||
(
|
||||
quote!(.ok_or(#bevy_reflect_path::ApplyError::MismatchedTypes {
|
||||
// The unwrap won't panic. By this point the #field_accessor would have been invoked once and any failure to
|
||||
// access the given field handled by the `resolve_missing` code bellow.
|
||||
from_type: ::core::convert::Into::into(
|
||||
#bevy_reflect_path::DynamicTypePath::reflect_type_path(#FQOption::unwrap(#field_accessor))
|
||||
),
|
||||
to_type: ::core::convert::Into::into(<#ty as #bevy_reflect_path::TypePath>::type_path())
|
||||
})?),
|
||||
quote!(.ok_or(#bevy_reflect_path::ApplyError::MissingEnumField {
|
||||
variant_name: ::core::convert::Into::into(#name),
|
||||
field_name: ::core::convert::Into::into(#field_ref_str)
|
||||
})?)
|
||||
)
|
||||
None => {
|
||||
if let Some(field_index) = field.field.reflection_index {
|
||||
quote!(#this.field_at(#field_index))
|
||||
} else {
|
||||
(quote!(?), quote!(?))
|
||||
quote!(::core::compile_error!(
|
||||
"internal bevy_reflect error: field should be active"
|
||||
))
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns a token stream that unwraps a field of a variant as a `&dyn Reflect`
|
||||
/// (from an `Option<dyn Reflect>`).
|
||||
///
|
||||
/// # Parameters
|
||||
/// * `field`: The field to access
|
||||
fn unwrap_field(&self, field: VariantField) -> TokenStream;
|
||||
|
||||
/// Returns a token stream that constructs a field of a variant as a concrete type
|
||||
/// (from a `&dyn Reflect`).
|
||||
///
|
||||
/// # Parameters
|
||||
/// * `field`: The field to access
|
||||
fn construct_field(&self, field: VariantField) -> TokenStream;
|
||||
|
||||
/// Returns a token stream that constructs an instance of an active field.
|
||||
///
|
||||
/// # Parameters
|
||||
/// * `this`: The identifier of the enum
|
||||
/// * `field`: The field to access
|
||||
fn on_active_field(&self, this: &Ident, field: VariantField) -> TokenStream {
|
||||
let field_accessor = self.access_field(this, field);
|
||||
|
||||
let alias = field.alias;
|
||||
let field_constructor = self.construct_field(field);
|
||||
|
||||
match &field.field.attrs.default {
|
||||
DefaultBehavior::Func(path) => quote! {
|
||||
if let #FQOption::Some(#alias) = #field_accessor {
|
||||
#field_constructor
|
||||
} else {
|
||||
#path()
|
||||
}
|
||||
},
|
||||
DefaultBehavior::Default => quote! {
|
||||
if let #FQOption::Some(#alias) = #field_accessor {
|
||||
#field_constructor
|
||||
} else {
|
||||
#FQDefault::default()
|
||||
}
|
||||
},
|
||||
DefaultBehavior::Required => {
|
||||
let field_unwrapper = self.unwrap_field(field);
|
||||
|
||||
quote! {{
|
||||
// `#alias` is used by both the unwrapper and constructor
|
||||
let #alias = #field_accessor;
|
||||
let #alias = #field_unwrapper;
|
||||
#field_constructor
|
||||
}}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns a token stream that constructs an instance of an ignored field.
|
||||
///
|
||||
/// # Parameters
|
||||
/// * `field`: The field to access
|
||||
fn on_ignored_field(&self, field: VariantField) -> TokenStream {
|
||||
match &field.field.attrs.default {
|
||||
DefaultBehavior::Func(path) => quote! { #path() },
|
||||
_ => quote! { #FQDefault::default() },
|
||||
}
|
||||
}
|
||||
|
||||
/// Builds the enum variant output data.
|
||||
fn build(&self, this: &Ident) -> EnumVariantOutputData {
|
||||
let variants = self.reflect_enum().variants();
|
||||
|
||||
let mut variant_names = Vec::with_capacity(variants.len());
|
||||
let mut variant_constructors = Vec::with_capacity(variants.len());
|
||||
|
||||
for variant in variants {
|
||||
let variant_ident = &variant.data.ident;
|
||||
let variant_name = variant_ident.to_string();
|
||||
let variant_path = self.reflect_enum().get_unit(variant_ident);
|
||||
|
||||
let fields = variant.fields();
|
||||
|
||||
let field_constructors = fields.iter().map(|field| {
|
||||
let member = ident_or_index(field.data.ident.as_ref(), field.declaration_index);
|
||||
let alias = format_ident!("_{}", member);
|
||||
|
||||
let variant_field = VariantField {
|
||||
alias: &alias,
|
||||
variant_name: &variant_name,
|
||||
field,
|
||||
};
|
||||
|
||||
match &field.attrs.default {
|
||||
DefaultBehavior::Func(path) => quote! {
|
||||
if let #FQOption::Some(field) = #field_accessor {
|
||||
<#field_ty as #bevy_reflect_path::FromReflect>::from_reflect(field)
|
||||
#resolve_error
|
||||
} else {
|
||||
#path()
|
||||
}
|
||||
},
|
||||
DefaultBehavior::Default => quote! {
|
||||
if let #FQOption::Some(field) = #field_accessor {
|
||||
<#field_ty as #bevy_reflect_path::FromReflect>::from_reflect(field)
|
||||
#resolve_error
|
||||
} else {
|
||||
#FQDefault::default()
|
||||
}
|
||||
},
|
||||
DefaultBehavior::Required => quote! {
|
||||
<#field_ty as #bevy_reflect_path::FromReflect>::from_reflect(#field_accessor #resolve_missing)
|
||||
#resolve_error
|
||||
},
|
||||
let value = if field.attrs.ignore.is_ignored() {
|
||||
self.on_ignored_field(variant_field)
|
||||
} else {
|
||||
self.on_active_field(this, variant_field)
|
||||
};
|
||||
|
||||
let constructor = quote! {
|
||||
#member: #value
|
||||
};
|
||||
|
||||
constructor
|
||||
});
|
||||
|
||||
let constructor = quote! {
|
||||
#variant_path {
|
||||
#( #field_constructors ),*
|
||||
}
|
||||
};
|
||||
quote! { #field_ident : #field_value }
|
||||
});
|
||||
variant_constructors.push(quote! {
|
||||
#variant_constructor { #( #constructor_fields ),* }
|
||||
});
|
||||
variant_names.push(name);
|
||||
}
|
||||
|
||||
EnumVariantConstructors {
|
||||
variant_names,
|
||||
variant_constructors,
|
||||
variant_names.push(variant_name);
|
||||
variant_constructors.push(constructor);
|
||||
}
|
||||
|
||||
EnumVariantOutputData {
|
||||
variant_names,
|
||||
variant_constructors,
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Generates the enum variant output data needed to build the `FromReflect::from_reflect` implementation.
|
||||
pub(crate) struct FromReflectVariantBuilder<'a> {
|
||||
reflect_enum: &'a ReflectEnum<'a>,
|
||||
}
|
||||
|
||||
impl<'a> FromReflectVariantBuilder<'a> {
|
||||
pub fn new(reflect_enum: &'a ReflectEnum) -> Self {
|
||||
Self { reflect_enum }
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a> VariantBuilder for FromReflectVariantBuilder<'a> {
|
||||
fn reflect_enum(&self) -> &ReflectEnum {
|
||||
self.reflect_enum
|
||||
}
|
||||
|
||||
fn unwrap_field(&self, field: VariantField) -> TokenStream {
|
||||
let alias = field.alias;
|
||||
quote!(#alias?)
|
||||
}
|
||||
|
||||
fn construct_field(&self, field: VariantField) -> TokenStream {
|
||||
let bevy_reflect_path = self.reflect_enum.meta().bevy_reflect_path();
|
||||
let field_ty = &field.field.data.ty;
|
||||
let alias = field.alias;
|
||||
|
||||
quote! {
|
||||
<#field_ty as #bevy_reflect_path::FromReflect>::from_reflect(#alias)?
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Generates the enum variant output data needed to build the `Reflect::try_apply` implementation.
|
||||
pub(crate) struct TryApplyVariantBuilder<'a> {
|
||||
reflect_enum: &'a ReflectEnum<'a>,
|
||||
}
|
||||
|
||||
impl<'a> TryApplyVariantBuilder<'a> {
|
||||
pub fn new(reflect_enum: &'a ReflectEnum) -> Self {
|
||||
Self { reflect_enum }
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a> VariantBuilder for TryApplyVariantBuilder<'a> {
|
||||
fn reflect_enum(&self) -> &ReflectEnum {
|
||||
self.reflect_enum
|
||||
}
|
||||
|
||||
fn unwrap_field(&self, field: VariantField) -> TokenStream {
|
||||
let VariantField {
|
||||
alias,
|
||||
variant_name,
|
||||
field,
|
||||
..
|
||||
} = field;
|
||||
|
||||
let bevy_reflect_path = self.reflect_enum.meta().bevy_reflect_path();
|
||||
|
||||
let field_name = match &field.data.ident {
|
||||
Some(ident) => format!("{ident}"),
|
||||
None => format!(".{}", field.declaration_index),
|
||||
};
|
||||
|
||||
quote! {
|
||||
#alias.ok_or(#bevy_reflect_path::ApplyError::MissingEnumField {
|
||||
variant_name: ::core::convert::Into::into(#variant_name),
|
||||
field_name: ::core::convert::Into::into(#field_name)
|
||||
})?
|
||||
}
|
||||
}
|
||||
|
||||
fn construct_field(&self, field: VariantField) -> TokenStream {
|
||||
let bevy_reflect_path = self.reflect_enum.meta().bevy_reflect_path();
|
||||
let alias = field.alias;
|
||||
let field_ty = &field.field.data.ty;
|
||||
|
||||
quote! {
|
||||
<#field_ty as #bevy_reflect_path::FromReflect>::from_reflect(#alias)
|
||||
.ok_or(#bevy_reflect_path::ApplyError::MismatchedTypes {
|
||||
from_type: ::core::convert::Into::into(
|
||||
#bevy_reflect_path::DynamicTypePath::reflect_type_path(#alias)
|
||||
),
|
||||
to_type: ::core::convert::Into::into(<#field_ty as #bevy_reflect_path::TypePath>::type_path())
|
||||
})?
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -1,6 +1,6 @@
|
|||
use crate::container_attributes::REFLECT_DEFAULT;
|
||||
use crate::derive_data::ReflectEnum;
|
||||
use crate::enum_utility::{get_variant_constructors, EnumVariantConstructors};
|
||||
use crate::enum_utility::{EnumVariantOutputData, FromReflectVariantBuilder, VariantBuilder};
|
||||
use crate::field_attributes::DefaultBehavior;
|
||||
use crate::utility::{ident_or_index, WhereClauseOptions};
|
||||
use crate::{ReflectMeta, ReflectStruct};
|
||||
|
|
@ -41,10 +41,12 @@ pub(crate) fn impl_enum(reflect_enum: &ReflectEnum) -> proc_macro2::TokenStream
|
|||
let bevy_reflect_path = reflect_enum.meta().bevy_reflect_path();
|
||||
|
||||
let ref_value = Ident::new("__param0", Span::call_site());
|
||||
let EnumVariantConstructors {
|
||||
|
||||
let EnumVariantOutputData {
|
||||
variant_names,
|
||||
variant_constructors,
|
||||
} = get_variant_constructors(reflect_enum, &ref_value, false);
|
||||
..
|
||||
} = FromReflectVariantBuilder::new(reflect_enum).build(&ref_value);
|
||||
|
||||
let (impl_generics, ty_generics, where_clause) = enum_path.generics().split_for_impl();
|
||||
|
||||
|
|
|
|||
|
|
@ -1,5 +1,5 @@
|
|||
use crate::derive_data::{EnumVariantFields, ReflectEnum, StructField};
|
||||
use crate::enum_utility::{get_variant_constructors, EnumVariantConstructors};
|
||||
use crate::enum_utility::{EnumVariantOutputData, TryApplyVariantBuilder, VariantBuilder};
|
||||
use crate::impls::{impl_type_path, impl_typed};
|
||||
use bevy_macro_utils::fq_std::{FQAny, FQBox, FQOption, FQResult};
|
||||
use proc_macro2::{Ident, Span};
|
||||
|
|
@ -27,10 +27,11 @@ pub(crate) fn impl_enum(reflect_enum: &ReflectEnum) -> proc_macro2::TokenStream
|
|||
enum_variant_type,
|
||||
} = generate_impls(reflect_enum, &ref_index, &ref_name);
|
||||
|
||||
let EnumVariantConstructors {
|
||||
let EnumVariantOutputData {
|
||||
variant_names,
|
||||
variant_constructors,
|
||||
} = get_variant_constructors(reflect_enum, &ref_value, true);
|
||||
..
|
||||
} = TryApplyVariantBuilder::new(reflect_enum).build(&ref_value);
|
||||
|
||||
let hash_fn = reflect_enum
|
||||
.meta()
|
||||
|
|
|
|||
Loading…
Reference in a new issue