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use std::fmt::Write;
use std::str::FromStr;
use super::super::TraitHandler;
use super::models::{FieldAttributeBuilder, TypeAttributeBuilder};
use crate::Trait;
use proc_macro2::TokenStream;
use quote::quote;
use syn::{punctuated::Punctuated, Data, DeriveInput, Fields, Generics, Meta};
pub struct CloneStructHandler;
impl TraitHandler for CloneStructHandler {
fn trait_meta_handler(
ast: &DeriveInput,
tokens: &mut TokenStream,
traits: &[Trait],
meta: &Meta,
) {
let type_attribute = TypeAttributeBuilder {
enable_flag: true,
enable_bound: true,
}
.from_clone_meta(meta);
let mut bound = Punctuated::new();
let mut clone_tokens = TokenStream::new();
let mut clone_from_tokens = TokenStream::new();
if let Data::Struct(data) = &ast.data {
let mut field_attributes = Vec::new();
let mut field_names = Vec::new();
#[cfg(feature = "Copy")]
let mut has_custom_clone_method = false;
for (index, field) in data.fields.iter().enumerate() {
let field_attribute = FieldAttributeBuilder {
enable_impl: true,
}
.from_attributes(&field.attrs, traits);
let field_name = if let Some(ident) = field.ident.as_ref() {
ident.to_string()
} else {
format!("{}", index)
};
#[cfg(feature = "Copy")]
if field_attribute.clone_method.is_some() {
has_custom_clone_method = true;
}
field_attributes.push(field_attribute);
field_names.push(field_name);
}
#[cfg(feature = "Copy")]
let contains_copy = !has_custom_clone_method && traits.contains(&Trait::Copy);
#[cfg(not(feature = "Copy"))]
let contains_copy = false;
if contains_copy {
bound = type_attribute
.bound
.into_punctuated_where_predicates_by_generic_parameters_with_copy(
&ast.generics.params,
);
clone_tokens.extend(quote!(*self));
let mut clone_from = String::new();
for field_name in field_names {
clone_from.write_fmt(format_args!("core::clone::Clone::clone_from(&mut self.{field_name}, &_source.{field_name});", field_name = field_name)).unwrap();
}
clone_from_tokens.extend(TokenStream::from_str(&clone_from).unwrap());
} else {
bound = type_attribute
.bound
.into_punctuated_where_predicates_by_generic_parameters(&ast.generics.params);
match &data.fields {
Fields::Unit => {
let ident = &ast.ident;
clone_tokens.extend(quote!(#ident));
}
Fields::Unnamed(_) => {
let mut clone = ast.ident.to_string();
let mut clone_from = String::new();
clone.push('(');
for (index, field_attribute) in field_attributes.into_iter().enumerate() {
let field_name = &field_names[index];
let clone_trait = field_attribute.clone_trait;
let clone_method = field_attribute.clone_method;
match clone_trait {
Some(clone_trait) => {
let clone_method = clone_method.unwrap();
clone
.write_fmt(format_args!(
"{clone_trait}::{clone_method}(&self.{field_name}),",
clone_trait = clone_trait,
clone_method = clone_method,
field_name = field_name
))
.unwrap();
clone_from.write_fmt(format_args!("self.{field_name} = {clone_trait}::{clone_method}(&_source.{field_name});", clone_trait = clone_trait, clone_method = clone_method, field_name = field_name)).unwrap();
}
None => {
match clone_method {
Some(clone_method) => {
clone
.write_fmt(format_args!(
"{clone_method}(&self.{field_name}),",
clone_method = clone_method,
field_name = field_name
))
.unwrap();
clone_from.write_fmt(format_args!("self.{field_name} = {clone_method}(&_source.{field_name});", clone_method = clone_method, field_name = field_name)).unwrap();
}
None => {
clone.write_fmt(format_args!("core::clone::Clone::clone(&self.{field_name}),", field_name = field_name)).unwrap();
clone_from.write_fmt(format_args!("core::clone::Clone::clone_from(&mut self.{field_name}, &_source.{field_name});", field_name = field_name)).unwrap();
}
}
}
}
}
clone.push(')');
clone_tokens.extend(TokenStream::from_str(&clone).unwrap());
clone_from_tokens.extend(TokenStream::from_str(&clone_from).unwrap());
}
Fields::Named(_) => {
let mut clone = ast.ident.to_string();
let mut clone_from = String::new();
clone.push('{');
for (index, field_attribute) in field_attributes.into_iter().enumerate() {
let field_name = &field_names[index];
let clone_trait = field_attribute.clone_trait;
let clone_method = field_attribute.clone_method;
match clone_trait {
Some(clone_trait) => {
let clone_method = clone_method.unwrap();
clone.write_fmt(format_args!("{field_name}: {clone_trait}::{clone_method}(&self.{field_name}),", clone_trait = clone_trait, clone_method = clone_method, field_name = field_name)).unwrap();
clone_from.write_fmt(format_args!("self.{field_name} = {clone_trait}::{clone_method}(&_source.{field_name});", clone_trait = clone_trait, clone_method = clone_method, field_name = field_name)).unwrap();
}
None => {
match clone_method {
Some(clone_method) => {
clone.write_fmt(format_args!("{field_name}: {clone_method}(&self.{field_name}),", clone_method = clone_method, field_name = field_name)).unwrap();
clone_from.write_fmt(format_args!("self.{field_name} = {clone_method}(&_source.{field_name});", clone_method = clone_method, field_name = field_name)).unwrap();
}
None => {
clone.write_fmt(format_args!("{field_name}: core::clone::Clone::clone(&self.{field_name}),", field_name = field_name)).unwrap();
clone_from.write_fmt(format_args!("core::clone::Clone::clone_from(&mut self.{field_name}, &_source.{field_name});", field_name = field_name)).unwrap();
}
}
}
}
}
clone.push('}');
clone_tokens.extend(TokenStream::from_str(&clone).unwrap());
clone_from_tokens.extend(TokenStream::from_str(&clone_from).unwrap());
}
}
}
}
let ident = &ast.ident;
let mut generics_cloned: Generics = ast.generics.clone();
let where_clause = generics_cloned.make_where_clause();
for where_predicate in bound {
where_clause.predicates.push(where_predicate);
}
let (impl_generics, ty_generics, where_clause) = generics_cloned.split_for_impl();
let compare_impl = quote! {
impl #impl_generics core::clone::Clone for #ident #ty_generics #where_clause {
#[inline]
fn clone(&self) -> Self {
#clone_tokens
}
#[inline]
fn clone_from(&mut self, _source: &Self) {
#clone_from_tokens
}
}
};
tokens.extend(compare_impl);
}
}
