1 files changed, 149 insertions, 0 deletions
diff --git a/vendor/educe/src/trait_handlers/default/default_struct.rs b/vendor/educe/src/trait_handlers/default/default_struct.rs
new file mode 100644
index 00000000..ea25b565
--- /dev/null
+++ b/vendor/educe/src/trait_handlers/default/default_struct.rs
@@ -0,0 +1,149 @@
+use quote::quote;
+use syn::{Data, DeriveInput, Fields, Meta, Type};
+
+use super::{
+    models::{FieldAttributeBuilder, TypeAttributeBuilder},
+    TraitHandler,
+};
+use crate::Trait;
+
+pub(crate) struct DefaultStructHandler;
+
+impl TraitHandler for DefaultStructHandler {
+    fn trait_meta_handler(
+        ast: &DeriveInput,
+        token_stream: &mut proc_macro2::TokenStream,
+        traits: &[Trait],
+        meta: &Meta,
+    ) -> syn::Result<()> {
+        let type_attribute = TypeAttributeBuilder {
+            enable_flag:       true,
+            enable_new:        true,
+            enable_expression: true,
+            enable_bound:      true,
+        }
+        .build_from_default_meta(meta)?;
+
+        let mut default_types: Vec<&Type> = Vec::new();
+
+        let mut default_token_stream = proc_macro2::TokenStream::new();
+
+        if let Data::Struct(data) = &ast.data {
+            if let Some(expression) = type_attribute.expression {
+                for field in data.fields.iter() {
+                    let _ = FieldAttributeBuilder {
+                        enable_flag:       false,
+                        enable_expression: false,
+                    }
+                    .build_from_attributes(&field.attrs, traits, &field.ty)?;
+                }
+
+                default_token_stream.extend(quote!(#expression));
+            } else {
+                match &data.fields {
+                    Fields::Unit => {
+                        default_token_stream.extend(quote!(Self));
+                    },
+                    Fields::Named(_) => {
+                        let mut fields_token_stream = proc_macro2::TokenStream::new();
+
+                        for field in data.fields.iter() {
+                            let field_attribute = FieldAttributeBuilder {
+                                enable_flag:       false,
+                                enable_expression: true,
+                            }
+                            .build_from_attributes(&field.attrs, traits, &field.ty)?;
+
+                            let field_name = field.ident.as_ref().unwrap();
+
+                            if let Some(expression) = field_attribute.expression {
+                                fields_token_stream.extend(quote! {
+                                    #field_name: #expression,
+                                });
+                            } else {
+                                let ty = &field.ty;
+
+                                default_types.push(ty);
+
+                                fields_token_stream.extend(quote! {
+                                    #field_name: <#ty as ::core::default::Default>::default(),
+                                });
+                            }
+                        }
+
+                        default_token_stream.extend(quote! {
+                            Self {
+                                #fields_token_stream
+                            }
+                        });
+                    },
+                    Fields::Unnamed(_) => {
+                        let mut fields_token_stream = proc_macro2::TokenStream::new();
+
+                        for field in data.fields.iter() {
+                            let field_attribute = FieldAttributeBuilder {
+                                enable_flag:       false,
+                                enable_expression: true,
+                            }
+                            .build_from_attributes(&field.attrs, traits, &field.ty)?;
+
+                            if let Some(expression) = field_attribute.expression {
+                                fields_token_stream.extend(quote!(#expression,));
+                            } else {
+                                let ty = &field.ty;
+
+                                default_types.push(ty);
+
+                                fields_token_stream
+                                    .extend(quote!(<#ty as ::core::default::Default>::default(),));
+                            }
+                        }
+
+                        default_token_stream.extend(quote!(Self ( #fields_token_stream )));
+                    },
+                }
+            }
+        }
+
+        let ident = &ast.ident;
+
+        let bound = type_attribute.bound.into_where_predicates_by_generic_parameters_check_types(
+            &ast.generics.params,
+            &syn::parse2(quote!(::core::default::Default)).unwrap(),
+            &default_types,
+            &[],
+        );
+
+        let mut generics = ast.generics.clone();
+        let where_clause = generics.make_where_clause();
+
+        for where_predicate in bound {
+            where_clause.predicates.push(where_predicate);
+        }
+
+        let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
+
+        token_stream.extend(quote! {
+            impl #impl_generics ::core::default::Default for #ident #ty_generics #where_clause {
+                #[inline]
+                fn default() -> Self {
+                    #default_token_stream
+                }
+            }
+        });
+
+        if type_attribute.new {
+            token_stream.extend(quote! {
+                impl #impl_generics #ident #ty_generics #where_clause {
+                    /// Returns the "default value" for a type.
+                    #[inline]
+                    pub fn new() -> Self {
+                        <Self as ::core::default::Default>::default()
+                    }
+                }
+            });
+        }
+
+        Ok(())
+    }
+}