use proc_macro2::TokenStream;
use quote::quote;
use syn::{TraitBound, TraitBoundModifier, TypeParamBound};
use crate::{Data, DataType, DeriveTrait, Item, SimpleType, Trait, TraitImpl};
pub struct Clone;
impl TraitImpl for Clone {
fn as_str(&self) -> &'static str {
"Clone"
}
fn default_derive_trait(&self) -> DeriveTrait {
DeriveTrait::Clone
}
fn supports_union(&self) -> bool {
true
}
fn additional_where_bounds(&self, data: &Item) -> Option<TypeParamBound> {
if let Item::Item(Data {
type_: DataType::Union(..),
..
}) = data
{
Some(TypeParamBound::Trait(TraitBound {
paren_token: None,
modifier: TraitBoundModifier::None,
lifetimes: None,
path: Trait::Copy.default_derive_trait().path(),
}))
} else {
None
}
}
fn build_signature(
&self,
item: &Item,
traits: &[DeriveTrait],
_trait_: &DeriveTrait,
body: &TokenStream,
) -> TokenStream {
if traits.iter().any(|trait_| trait_ == Trait::Copy) {
return quote! {
#[inline]
fn clone(&self) -> Self { *self }
};
}
if let Item::Item(Data {
type_: DataType::Union(..),
..
}) = item
{
quote! {
#[inline]
fn clone(&self) -> Self {
struct __AssertCopy<__T: ::core::marker::Copy + ?::core::marker::Sized>(::core::marker::PhantomData<__T>);
let _: __AssertCopy<Self>;
*self
}
}
} else {
quote! {
#[inline]
fn clone(&self) -> Self {
match self {
#body
}
}
}
}
}
fn build_body(&self, traits: &[DeriveTrait], trait_: &DeriveTrait, data: &Data) -> TokenStream {
if traits.iter().any(|trait_| trait_ == Trait::Copy) {
return TokenStream::new();
}
match data.simple_type() {
SimpleType::Struct(fields) => {
let self_pattern = &fields.self_pattern;
let item_path = &data.path;
let self_ident = data.iter_self_ident(**trait_);
let fields = data.iter_field_ident(**trait_);
let trait_path = trait_.path();
quote! {
#self_pattern => #item_path { #(#fields: #trait_path::clone(#self_ident)),* },
}
}
SimpleType::Tuple(fields) => {
let self_pattern = &fields.self_pattern;
let item_path = &data.path;
let self_ident = data.iter_self_ident(**trait_);
let trait_path = trait_.path();
quote! {
#self_pattern => #item_path(#(#trait_path::clone(#self_ident)),*),
}
}
SimpleType::Unit(pattern) => {
quote! { #pattern => #pattern, }
}
SimpleType::Union(_) => TokenStream::new(),
}
}
}