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#![recursion_limit = "128"]
extern crate proc_macro;
extern crate syn;
#[macro_use]
extern crate quote;
use proc_macro::TokenStream;
use quote::{ToTokens, Tokens};
use std::ops::Deref;
use syn::{Data, DeriveInput, Field, Fields, Index, Meta};
enum StructField<'a> {
Numbered(Index, &'a Field),
Named(&'a Field),
}
impl<'a> From<(usize, &'a Field)> for StructField<'a> {
fn from((n, f): (usize, &'a Field)) -> Self {
match f.ident {
Some(_) => StructField::Named(f),
None => StructField::Numbered(n.into(), f),
}
}
}
impl<'a> Deref for StructField<'a> {
type Target = Field;
fn deref(&self) -> &Field {
match self {
&StructField::Numbered(_, ref f) => f,
&StructField::Named(ref f) => f,
}
}
}
impl<'a> ToTokens for StructField<'a> {
fn to_tokens(&self, tokens: &mut Tokens) {
tokens.append_all(match self {
&StructField::Numbered(ref n, _) => quote! { #n },
&StructField::Named(&Field {
ident: Some(ref i), ..
}) => quote! { #i },
_ => unreachable!(),
})
}
}
#[proc_macro_derive(MutexProtected, attributes(mutex))]
pub fn derive_zero(input: TokenStream) -> TokenStream {
let input: DeriveInput = syn::parse(input).unwrap();
let name = input.ident;
let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
let mut types = vec![];
match input.data {
Data::Struct(ref data) => match data.fields {
Fields::Named(ref fields) => types.extend(&fields.named),
Fields::Unnamed(ref fields) => types.extend(&fields.unnamed),
Fields::Unit => {}
},
_ => panic!("Can only derive(MutexProtected) for structs"),
}
let (mut mutexes, others): (Vec<_>, Vec<_>) = types
.into_iter()
.enumerate()
.map(StructField::from)
.partition(|f| {
f.attrs.iter().any(|a| match a.interpret_meta() {
Some(Meta::Word(id)) if id == "mutex" => true,
Some(ref meta) if meta.name() == "mutex" => panic!("Expected #[mutex]"),
_ => false,
})
});
let mutex = match mutexes.len() {
0 => panic!("Missing #[mutex]"),
1 => mutexes.pop().unwrap(),
_ => panic!("Can only have one #[mutex]"),
};
let mutex_ty = &mutex.ty;
let (data_ty, data, data_mut, into_data) = match others.len() {
0 => panic!("{} contains nothing else than a #[mutex] field", name),
1 => {
let other = &others[0];
let other_ty = &other.ty;
let data_ty = quote! { #other_ty };
let data = quote! { &self.#other };
let data_mut = quote! { &mut self.#other };
let into_data = quote! { self.#other };
(data_ty, data, data_mut, into_data)
}
_ => {
let data_ty = quote! { #name #ty_generics };
let data = quote! { self };
let data_mut = data.clone();
let into_data = data.clone();
(data_ty, data, data_mut, into_data)
}
};
let expanded = quote!{
impl #impl_generics ::flexible_locks::MutexProtected for #name #ty_generics #where_clause {
type MutexType = #mutex_ty;
type DataType = #data_ty;
fn get_mutex(&self) -> &Self::MutexType {
&self.#mutex
}
fn get_mutex_mut(&mut self) -> &mut Self::MutexType {
&mut self.#mutex
}
fn get_data(&self) -> &Self::DataType {
#data
}
fn get_data_mut(&mut self) -> &mut Self::DataType {
#data_mut
}
fn into_data(self) -> Self::DataType where Self::DataType: Sized {
unsafe { self.get_mutex().destroy(); }
#into_data
}
}
};
expanded.into()
}