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#![recursion_limit = "256"]
extern crate diesel;
extern crate diesel_derives_traits;
extern crate proc_macro;
extern crate proc_macro2;
extern crate quote;
extern crate syn;
use proc_macro::TokenStream;
use proc_macro2::TokenStream as TokenStream2;
use quote::{quote, ToTokens};
use syn::{parse_macro_input, DeriveInput, Meta, MetaList, NestedMeta};
fn get_idents() -> Vec<TokenStream2> {
let mut idents = Vec::new();
#[cfg(feature = "postgres")]
{
idents.push(quote!(::diesel::pg::PgConnection));
}
#[cfg(feature = "logger")]
{
#[cfg(feature = "postgres")]
{
idents.push(quote!(
::diesel_logger::LoggingConnection<::diesel::pg::PgConnection>
));
}
}
idents
}
#[proc_macro_derive(Model)]
pub fn derive_model(input: TokenStream) -> TokenStream {
expand_derive(input, impl_model)
}
fn impl_model(item: &DeriveInput) -> TokenStream2 {
let name = &item.ident;
get_idents()
.iter()
.map(|conn_impl| {
quote!(
impl<'a> ::diesel_derives_traits::Model<'a, #conn_impl> for #name
{
fn save(self, conn: &#conn_impl) -> ::diesel::result::QueryResult<Self> {
::diesel::RunQueryDsl::get_result(
::diesel::update(
&self
)
.set(&self),
conn
)
.map_err(|e| e.into())
}
fn find_all(conn: &#conn_impl) -> ::diesel::result::QueryResult<Vec<Self>> {
::diesel::RunQueryDsl::load(
<Self as ::diesel::associations::HasTable>::table(),
conn
)
.map_err(|e| e.into())
}
fn find_one(conn: &#conn_impl, id: <&'a Self as ::diesel::Identifiable>::Id) -> ::diesel::result::QueryResult<Option<Self>> {
use diesel::{OptionalExtension, QueryDsl};
::diesel::RunQueryDsl::get_result(
<Self as ::diesel::associations::HasTable>::table().find(id),
conn
)
.optional()
.map_err(|e| e.into())
}
fn exists(conn: &#conn_impl, id: <&'a Self as ::diesel::associations::Identifiable>::Id) -> ::diesel::result::QueryResult<bool> {
use diesel::QueryDsl;
::diesel::RunQueryDsl::get_result(
::diesel::select(::diesel::dsl::exists(<Self as ::diesel::associations::HasTable>::table().find(id))),
conn
)
.map_err(|e| e.into())
}
fn count_all(conn: &#conn_impl) -> ::diesel::result::QueryResult<i64> {
use diesel::QueryDsl;
::diesel::RunQueryDsl::get_result(
<Self as ::diesel::associations::HasTable>::table().count(),
conn
)
.map_err(|e| e.into())
}
fn destroy(self, conn: &#conn_impl) -> ::diesel::result::QueryResult<()> {
::diesel::RunQueryDsl::execute(
::diesel::delete(&self),
conn
)?;
Ok(())
}
}
)
}).collect()
}
#[proc_macro_derive(NewModel, attributes(model))]
pub fn derive_new_model(input: TokenStream) -> TokenStream {
expand_derive(input, impl_new_model)
}
fn impl_new_model(item: &DeriveInput) -> TokenStream2 {
let name = &item.ident;
let mut tokens = TokenStream2::new();
name.to_tokens(&mut tokens);
item.generics.to_tokens(&mut tokens);
let target = item
.attrs
.iter()
.find(|attr| attr.path.segments[0].ident == "model")
.expect("\"model\" attribute must be specified for #[derive(NewModel)]");
let target_name = match target
.parse_meta()
.expect("Must be in the form of `#[model(MyModel)]`")
{
Meta::List(MetaList { ref nested, .. }) if !nested.is_empty() => match nested[0] {
NestedMeta::Meta(Meta::Path(ref ident)) => ident.clone(),
_ => panic!("Must be in the form of `#[model(MyModel)]`"),
},
_ => panic!("Must be in the form of `#[model(MyModel)]`"),
};
get_idents()
.iter()
.map(|conn_impl| {
quote!(
impl<'a> ::diesel_derives_traits::NewModel<'a, #target_name, #conn_impl> for #tokens
{
fn save(self, conn: &#conn_impl) -> ::diesel::result::QueryResult<#target_name> {
::diesel::RunQueryDsl::get_result(
::diesel::insert_into(<#target_name as ::diesel::associations::HasTable>::table())
.values(&self),
conn
)
.map_err(|e| e.into())
}
}
)
}).collect()
}
fn expand_derive(input: TokenStream, f: fn(&DeriveInput) -> TokenStream2) -> TokenStream {
let item = parse_macro_input!(input as DeriveInput);
f(&item).to_string().parse().unwrap()
}