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use proc_macro2; use proc_macro2::Span; use syn; use field::*; use model::*; use util::*; pub fn derive(item: syn::DeriveInput) -> Result<proc_macro2::TokenStream, Diagnostic> { let model = Model::from_item(&item)?; if model.fields().is_empty() { return Err(Span::call_site() .error("Cannot derive Insertable for unit structs") .help(format!( "Use `insert_into({}::table).default_values()` if you want `DEFAULT VALUES`", model.table_name() ))); } let table_name = &model.table_name(); let struct_name = &item.ident; let (_, ty_generics, where_clause) = item.generics.split_for_impl(); let mut impl_generics = item.generics.clone(); impl_generics.params.push(parse_quote!('insert)); let (impl_generics, ..) = impl_generics.split_for_impl(); let (direct_field_ty, direct_field_assign): (Vec<_>, Vec<_>) = model .fields() .iter() .map(|f| { ( (field_ty(f, table_name, None)), (field_expr(f, table_name, None)), ) }) .unzip(); let (ref_field_ty, ref_field_assign): (Vec<_>, Vec<_>) = model .fields() .iter() .map(|f| { ( (field_ty(f, table_name, Some(quote!(&'insert)))), (field_expr(f, table_name, Some(quote!(&)))), ) }) .unzip(); Ok(wrap_in_dummy_mod( model.dummy_mod_name("insertable"), quote! { use diesel::insertable::Insertable; use diesel::query_builder::UndecoratedInsertRecord; use diesel::prelude::*; impl #impl_generics Insertable<#table_name::table> for #struct_name #ty_generics #where_clause { type Values = <(#(#direct_field_ty,)*) as Insertable<#table_name::table>>::Values; fn values(self) -> Self::Values { (#(#direct_field_assign,)*).values() } } impl #impl_generics Insertable<#table_name::table> for &'insert #struct_name #ty_generics #where_clause { type Values = <(#(#ref_field_ty,)*) as Insertable<#table_name::table>>::Values; fn values(self) -> Self::Values { (#(#ref_field_assign,)*).values() } } impl #impl_generics UndecoratedInsertRecord<#table_name::table> for #struct_name #ty_generics #where_clause { } }, )) } fn field_ty( field: &Field, table_name: &syn::Ident, lifetime: Option<proc_macro2::TokenStream>, ) -> syn::Type { if field.has_flag("embed") { let field_ty = &field.ty; parse_quote!(#lifetime #field_ty) } else { let inner_ty = inner_of_option_ty(&field.ty); let column_name = field.column_name(); parse_quote!( std::option::Option<diesel::dsl::Eq< #table_name::#column_name, #lifetime #inner_ty, >> ) } } fn field_expr( field: &Field, table_name: &syn::Ident, lifetime: Option<proc_macro2::TokenStream>, ) -> syn::Expr { let field_access = field.name.access(); if field.has_flag("embed") { parse_quote!(#lifetime self#field_access) } else { let column_name = field.column_name(); let column: syn::Expr = parse_quote!(#table_name::#column_name); if is_option_ty(&field.ty) { if lifetime.is_some() { parse_quote!(self#field_access.as_ref().map(|x| #column.eq(x))) } else { parse_quote!(self#field_access.map(|x| #column.eq(x))) } } else { parse_quote!(std::option::Option::Some(#column.eq(#lifetime self#field_access))) } } }