use proc_macro2::TokenStream;
use syn::DeriveInput;
use model::Model;
use util::{ty_for_foreign_derive, wrap_in_dummy_mod};
pub fn derive(item: DeriveInput) -> TokenStream {
let model = Model::from_item(&item, true);
if model.sql_types.is_empty() {
abort_call_site!(
"At least one `sql_type` is needed for deriving `AsExpression` on a structure."
);
}
let struct_ty = ty_for_foreign_derive(&item, &model);
let (impl_generics, ..) = item.generics.split_for_impl();
let lifetimes = item.generics.lifetimes().collect::<Vec<_>>();
let ty_params = item.generics.type_params().collect::<Vec<_>>();
let const_params = item.generics.const_params().collect::<Vec<_>>();
let tokens = model.sql_types.iter().map(|sql_type| {
let lifetimes = &lifetimes;
let ty_params = &ty_params;
let const_params = &const_params;
let tokens = quote!(
impl<'expr, #(#lifetimes,)* #(#ty_params,)* #(#const_params,)*> AsExpression<#sql_type>
for &'expr #struct_ty
{
type Expression = Bound<#sql_type, Self>;
fn as_expression(self) -> Self::Expression {
Bound::new(self)
}
}
impl<'expr, #(#lifetimes,)* #(#ty_params,)* #(#const_params,)*> AsExpression<Nullable<#sql_type>>
for &'expr #struct_ty
{
type Expression = Bound<Nullable<#sql_type>, Self>;
fn as_expression(self) -> Self::Expression {
Bound::new(self)
}
}
impl<'expr2, 'expr, #(#lifetimes,)* #(#ty_params,)* #(#const_params,)*> AsExpression<#sql_type>
for &'expr2 &'expr #struct_ty
{
type Expression = Bound<#sql_type, Self>;
fn as_expression(self) -> Self::Expression {
Bound::new(self)
}
}
impl<'expr2, 'expr, #(#lifetimes,)* #(#ty_params,)* #(#const_params,)*> AsExpression<Nullable<#sql_type>>
for &'expr2 &'expr #struct_ty
{
type Expression = Bound<Nullable<#sql_type>, Self>;
fn as_expression(self) -> Self::Expression {
Bound::new(self)
}
}
impl<#(#lifetimes,)* #(#ty_params,)* __DB, #(#const_params,)*> diesel::serialize::ToSql<Nullable<#sql_type>, __DB>
for #struct_ty
where
__DB: diesel::backend::Backend,
Self: ToSql<#sql_type, __DB>,
{
fn to_sql<'__b>(&'__b self, out: &mut Output<'__b, '_, __DB>) -> serialize::Result
{
ToSql::<#sql_type, __DB>::to_sql(self, out)
}
}
);
if model.not_sized {
tokens
} else {
quote!(
#tokens
impl#impl_generics AsExpression<#sql_type> for #struct_ty {
type Expression = Bound<#sql_type, Self>;
fn as_expression(self) -> Self::Expression {
Bound::new(self)
}
}
impl#impl_generics AsExpression<Nullable<#sql_type>> for #struct_ty {
type Expression = Bound<Nullable<#sql_type>, Self>;
fn as_expression(self) -> Self::Expression {
Bound::new(self)
}
}
)
}
});
wrap_in_dummy_mod(quote! {
use diesel::expression::AsExpression;
use diesel::internal::derives::as_expression::Bound;
use diesel::sql_types::Nullable;
use diesel::serialize::{self, ToSql, Output};
#(#tokens)*
})
}