lyra-engine/lyra-reflect/lyra-reflect-derive/src/struct_derive.rs

498 lines
15 KiB
Rust

use quote::{quote, ToTokens};
use syn::{DeriveInput, parse_quote, DataStruct};
use crate::{add_trait_bounds, FieldAttributes};
#[derive(Debug, PartialEq, Eq)]
enum StructType {
Unit,
Named,
Tuple,
}
impl StructType {
pub fn new(data: &DataStruct) -> Self {
if let Some(first) = data.fields.iter().next() {
if first.ident.is_some() {
Self::Named
} else {
Self::Tuple
}
} else {
Self::Unit
}
}
}
/// Generates code that matches a string with a struct's field name, and returns an Option that
/// contains a borrow (mutable borrow if `is_mut` is true) to the matching struct field.
///
/// Example:
/// ```compile_fail
/// // when `is_mut` = false
/// match name {
/// "x" => Some(&self.x),
/// "y" => Some(&self.y),
/// _ => None,
/// }
///
/// // when `is_mut` = true
/// match name {
/// "x" => Some(&mut self.x),
/// "y" => Some(&mut self.y),
/// _ => None,
/// }
/// ```
///
/// If the struct is a unit or tuple struct, None will always be returned
fn gen_struct_field_match(data: &DataStruct, is_mut: bool) -> proc_macro2::TokenStream {
let ty = StructType::new(data);
if ty == StructType::Named {
let mut_tkn = if is_mut {
quote! {
mut
}
} else { quote!{} };
let field_arms = data.fields.iter().map(|field| {
let field_ident = field.ident.as_ref().expect("Struct is missing field ident!");
let field_name_str = field_ident.to_string();
let attrs = FieldAttributes::from_vec(&field.attrs)
.expect("Failure to parse reflect attributes");
if attrs.has_skip() {
quote! {
#field_name_str => None
}
} else {
quote! {
#field_name_str => Some(&#mut_tkn self.#field_ident)
}
}
});
quote! {
match name {
#(#field_arms,)*
_ => None,
}
}
} else { quote!(None) }
}
/// Generates code that matches a string with a struct's field name, and sets that field value
/// with the provided `val`.
///
/// Example:
/// ```compile_fail
/// match name {
/// "x" => self.x = any_val.downcast_ref::<f32>()
/// .expect(&format!("Cannot set struct's field of {} type to the provided type of {}", "f32", val.name()))
/// .clone(),
/// "y" => self.y = any_val.downcast_ref::<f32>()
/// .expect(&format!("Cannot set struct's field of {} type to the provided type of {}", "f32", val.name()))
/// .clone()
/// _ => {
/// return false;
/// },
/// }
/// ```
fn gen_struct_set_field_match(data: &DataStruct) -> proc_macro2::TokenStream {
let ty = StructType::new(data);
if ty == StructType::Named {
let field_arms = data.fields.iter().map(|field| {
let field_ident = field.ident.as_ref().expect("Struct is missing field ident!");
let field_name_str = field_ident.to_string();
let field_ty = &field.ty;
let attrs = FieldAttributes::from_vec(&field.attrs)
.expect("Failure to parse reflect attributes");
if attrs.has_skip() {
quote! {
#field_name_str => {}
}
} else {
quote! {
#field_name_str => self.#field_ident = any_val.downcast_ref::<#field_ty>()
.expect(&format!("Cannot set struct's field of {} type to the provided type of {}", #field_name_str, val.name()))
.clone() //Some(&#mut_tkn self.#field_ident)
}
}
});
quote! {
let any_val = val.as_any();
match name {
#(#field_arms,)*
_ => {
return false;
},
}
true
}
} else { quote!(return false;) }
}
/// Generates code that matches a string with a struct's field name, and returns a string that is
/// the type of the field.
///
/// Example:
/// ```compile_fail
/// match name {
/// "x" => Some("f32"),
/// "y" => Some("f32"),
/// _ => None,
/// }
/// ```
fn gen_struct_field_name_match(data: &DataStruct) -> proc_macro2::TokenStream {
let ty = StructType::new(data);
if ty == StructType::Named {
let field_arms = data.fields.iter().map(|field| {
let field_ident = field.ident.as_ref().expect("Struct is missing field ident!");
let field_name_str = field_ident.to_string();
let mut field_ty_stream = proc_macro2::TokenStream::new();
field.ty.to_tokens(&mut field_ty_stream);
let s = field_ty_stream.to_string();
quote! {
#field_name_str => Some(#s)
}
});
quote! {
match name {
#(#field_arms,)*
_ => None,
}
}
} else { quote!(None) }
}
/// Generates code that matches a string with a struct's field name, and sets that field value
/// with the provided `val`.
///
/// Example:
/// ```compile_fail
/// match name {
/// 0 => self.x = any_val.downcast_ref::<f32>()
/// .expect(&format!("Cannot set struct's field of {} type to the provided type of {}", "f32", val.name()))
/// .clone(),
/// 1 => self.y = any_val.downcast_ref::<f32>()
/// .expect(&format!("Cannot set struct's field of {} type to the provided type of {}", "f32", val.name()))
/// .clone()
/// _ => {
/// return false;
/// },
/// }
/// ```
fn gen_struct_set_field_match_idx(data: &DataStruct) -> proc_macro2::TokenStream {
let ty = StructType::new(data);
if ty == StructType::Unit {
return quote!( return false; );
}
let field_arms = data.fields.iter().enumerate().map(|(idx, field)| {
let field_ty = &field.ty;
let attrs = FieldAttributes::from_vec(&field.attrs)
.expect("Failure to parse reflect attributes");
if attrs.has_skip() {
return quote! {
#idx => {}
};
}
if let Some(field_ident) = &field.ident {
let field_name_str = field_ident.to_string();
quote! {
#idx => self.#field_ident = any_val.downcast_ref::<#field_ty>()
.expect(&format!("Cannot set struct's field of {} to the provided type of {}", #field_name_str, val.name()))
.clone()
}
} else {
let sidx = syn::Index::from(idx);
quote! {
#idx => self.#sidx = any_val.downcast_ref::<#field_ty>()
.expect(&format!("Cannot set struct's field at {} to the provided type of {}", #idx, val.name()))
.clone()
}
}
});
quote! {
let any_val = val.as_any();
match idx {
#(#field_arms,)*
_ => {
return false;
},
}
true
}
}
/// Generates code that matches an index with the correct field in the struct, and returns the
/// type of the field.
///
/// Example:
/// ```compile_fail
/// match name {
/// 0 => Some("f32"),
/// 1 => Some("f32"),
/// _ => None,
/// }
/// ```
fn gen_struct_field_name_match_idx(data: &DataStruct) -> proc_macro2::TokenStream {
let field_arms = data.fields.iter().enumerate().map(|(idx, field)| {
let mut field_ty_stream = proc_macro2::TokenStream::new();
field.ty.to_tokens(&mut field_ty_stream);
let field_ty_str = field_ty_stream.to_string();
quote! {
#idx => Some(#field_ty_str)
}
});
quote! {
match idx {
#(#field_arms,)*
_ => None,
}
}
}
/// Generates code that matches an index with the position of the field in a struct,
/// and returns an Option that contains a borrow (mutable borrow if `is_mut` is true)
/// to the matching struct field.
///
/// Example:
/// ```compile_fail
/// // when `is_mut` = false
/// match idx {
/// 0 => Some(&self.x),
/// 1 => Some(&self.y),
/// _ => None,
/// }
///
/// // when `is_mut` = true
/// match idx {
/// 0 => Some(&mut self.x),
/// 1 => Some(&mut self.y),
/// _ => None,
/// }
/// ```
fn gen_struct_field_match_idx(data: &DataStruct, is_mut: bool) -> proc_macro2::TokenStream {
let ty = StructType::new(data);
if ty == StructType::Unit {
return quote!(None);
}
let mut_tkn = if is_mut {
quote! {
mut
}
} else { quote!{} };
let field_arms = data.fields.iter().enumerate().map(|(idx, field)| {
let attrs = FieldAttributes::from_vec(&field.attrs)
.expect("Failure to parse reflect attributes");
if attrs.has_skip() {
return quote! {
#idx => None
};
}
if let Some(field_ident) = &field.ident {
quote! {
#idx => Some(&#mut_tkn self.#field_ident)
}
} else {
let sidx = syn::Index::from(idx);
quote! {
#idx => Some(&#mut_tkn self.#sidx)
}
}
});
quote! {
match idx {
#(#field_arms,)*
_ => None,
}
}
}
/// Generates code that matches an index with the position of the field in a struct,
/// and returns an Option that contains the name of the field.
///
/// Example:
/// ```compile_fail
/// match idx {
/// 0 => Some("x"),
/// 1 => Some("y"),
/// _ => None,
/// }
/// ```
fn gen_struct_field_name_idx(data: &DataStruct) -> proc_macro2::TokenStream {
let ty = StructType::new(data);
if ty == StructType::Named {
let field_arms = data.fields.iter().enumerate().map(|(idx, field)| {
let field_ident = field.ident.as_ref().expect("Struct is missing field ident!");
let field_name_str = field_ident.to_string();
quote! {
#idx => Some(#field_name_str)
}
});
quote! {
match idx {
#(#field_arms,)*
_ => None,
}
}
} else {
quote!(None)
}
}
/// Generates a token stream that implements Reflect and Struct for the provided struct
pub fn derive_reflect_struct(input: &DeriveInput, data_struct: &DataStruct) -> proc_macro2::TokenStream {
let type_path = &input.ident;
let name = type_path.to_string();
//let name = type_path.span().source_text().unwrap();
let field_len = data_struct.fields.len();
let get_field_match = gen_struct_field_match(data_struct, false);
let get_field_mut_match = gen_struct_field_match(data_struct, true);
let get_field_match_idx = gen_struct_field_match_idx(data_struct, false);
let get_field_mut_match_idx = gen_struct_field_match_idx(data_struct, true);
let set_field_named = gen_struct_set_field_match(data_struct);
let set_field_idx = gen_struct_set_field_match_idx(data_struct);
let get_field_name_match = gen_struct_field_name_match(data_struct);
let get_field_name_match_idx = gen_struct_field_name_match_idx(data_struct);
let field_name_at = gen_struct_field_name_idx(data_struct);
let generics = add_trait_bounds(input.generics.clone(), vec![parse_quote!(Reflect), parse_quote!(Clone)]);
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
quote! {
impl #impl_generics lyra_engine::reflect::Reflect for #type_path #ty_generics #where_clause {
fn name(&self) -> String {
#name.to_string()
}
fn type_id(&self) -> std::any::TypeId {
std::any::TypeId::of::<#type_path #ty_generics>()
}
fn as_any(&self) -> &dyn std::any::Any {
self
}
fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
self
}
fn as_boxed_any(self: Box<Self>) -> Box<dyn std::any::Any> {
self
}
fn apply(&mut self, val: &dyn lyra_engine::reflect::Reflect) {
let val = val.as_any().downcast_ref::<Self>()
.expect(&format!("`self` was not {}", #name));
*self = val.clone();
}
fn clone_inner(&self) -> Box<dyn lyra_engine::reflect::Reflect> {
Box::new(self.clone())
}
fn reflect_ref(&self) -> lyra_engine::reflect::ReflectRef {
lyra_engine::reflect::ReflectRef::Struct(self)
}
fn reflect_mut(&mut self) -> lyra_engine::reflect::ReflectMut {
lyra_engine::reflect::ReflectMut::Struct(self)
}
fn reflect_val(&self) -> &dyn lyra_engine::reflect::Reflect {
self
}
fn reflect_val_mut(&mut self) -> &mut dyn lyra_engine::reflect::Reflect {
self
}
}
impl #impl_generics lyra_engine::reflect::Struct for #type_path #ty_generics #where_clause {
fn field(&self, name: &str) -> Option<&dyn lyra_engine::reflect::Reflect> {
let name = name.to_lowercase();
let name = name.as_str();
#get_field_match
}
fn field_mut(&mut self, name: &str) -> Option<&mut dyn lyra_engine::reflect::Reflect> {
let name = name.to_lowercase();
let name = name.as_str();
#get_field_mut_match
}
fn fields_len(&self) -> usize {
#field_len
}
fn field_at(&self, idx: usize) -> Option<&dyn lyra_engine::reflect::Reflect> {
#get_field_match_idx
}
fn field_at_mut(&mut self, idx: usize) -> Option<&mut dyn lyra_engine::reflect::Reflect> {
#get_field_mut_match_idx
}
fn field_name_at(&self, idx: usize) -> Option<&str> {
#field_name_at
}
fn set_field(&mut self, name: &str, val: &dyn lyra_engine::reflect::Reflect) -> bool {
#set_field_named
}
fn set_field_at(&mut self, idx: usize, val: &dyn lyra_engine::reflect::Reflect) -> bool {
#set_field_idx
}
fn field_type(&self, name: &str) -> Option<&'static str> {
#get_field_name_match
}
fn field_type_at(&self, idx: usize) -> Option<&'static str> {
#get_field_name_match_idx
}
fn method(&self, name: &str) -> Option<&lyra_engine::reflect::Method> {
unimplemented!()
}
fn method_at(&self, idx: usize) -> Option<&lyra_engine::reflect::Method> {
unimplemented!()
}
fn methods_len(&self) -> usize {
unimplemented!()
}
}
}
}