/
routable_derive.rs
254 lines (219 loc) · 7.93 KB
/
routable_derive.rs
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use proc_macro2::TokenStream;
use quote::quote;
use syn::parse::{Parse, ParseStream};
use syn::punctuated::Punctuated;
use syn::spanned::Spanned;
use syn::{Data, DeriveInput, Fields, Ident, LitStr, Variant};
const AT_ATTR_IDENT: &str = "at";
const NOT_FOUND_ATTR_IDENT: &str = "not_found";
pub struct Routable {
ident: Ident,
ats: Vec<LitStr>,
variants: Punctuated<Variant, syn::token::Comma>,
not_found_route: Option<Ident>,
}
impl Parse for Routable {
fn parse(input: ParseStream) -> syn::Result<Self> {
let DeriveInput { ident, data, .. } = input.parse()?;
let data = match data {
Data::Enum(data) => data,
Data::Struct(s) => {
return Err(syn::Error::new(
s.struct_token.span(),
"expected enum, found struct",
))
}
Data::Union(u) => {
return Err(syn::Error::new(
u.union_token.span(),
"expected enum, found union",
))
}
};
let (not_found_route, ats) = parse_variants_attributes(&data.variants)?;
Ok(Self {
ident,
variants: data.variants,
ats,
not_found_route,
})
}
}
fn parse_variants_attributes(
variants: &Punctuated<Variant, syn::token::Comma>,
) -> syn::Result<(Option<Ident>, Vec<LitStr>)> {
let mut not_founds = vec![];
let mut ats: Vec<LitStr> = vec![];
let mut not_found_attrs = vec![];
for variant in variants.iter() {
if let Fields::Unnamed(ref field) = variant.fields {
return Err(syn::Error::new(
field.span(),
"only named fields are supported",
));
}
let attrs = &variant.attrs;
let at_attrs = attrs
.iter()
.filter(|attr| attr.path().is_ident(AT_ATTR_IDENT))
.collect::<Vec<_>>();
let attr = match at_attrs.len() {
1 => *at_attrs.first().unwrap(),
0 => {
return Err(syn::Error::new(
variant.span(),
format!("{AT_ATTR_IDENT} attribute must be present on every variant"),
))
}
_ => {
return Err(syn::Error::new_spanned(
quote! { #(#at_attrs)* },
format!("only one {AT_ATTR_IDENT} attribute must be present"),
))
}
};
let lit = attr.parse_args::<LitStr>()?;
let val = lit.value();
if val.find('#').is_some() {
return Err(syn::Error::new_spanned(
lit,
"You cannot use `#` in your routes. Please consider `HashRouter` instead.",
));
}
if !val.starts_with('/') {
return Err(syn::Error::new_spanned(
lit,
"relative paths are not supported at this moment.",
));
}
ats.push(lit);
for attr in attrs.iter() {
if attr.path().is_ident(NOT_FOUND_ATTR_IDENT) {
not_found_attrs.push(attr);
not_founds.push(variant.ident.clone())
}
}
}
if not_founds.len() > 1 {
return Err(syn::Error::new_spanned(
quote! { #(#not_found_attrs)* },
format!("there can only be one {NOT_FOUND_ATTR_IDENT}"),
));
}
Ok((not_founds.into_iter().next(), ats))
}
impl Routable {
fn build_from_path(&self) -> TokenStream {
let from_path_matches = self.variants.iter().enumerate().map(|(i, variant)| {
let ident = &variant.ident;
let right = match &variant.fields {
Fields::Unit => quote! { Self::#ident },
Fields::Named(field) => {
let fields = field.named.iter().map(|it| {
// named fields have idents
it.ident.as_ref().unwrap()
});
quote! { Self::#ident { #(#fields: {
let param = params.get(stringify!(#fields))?;
let param = &*::yew_router::__macro::decode_for_url(param).ok()?;
let param = param.parse().ok()?;
param
},)* } }
}
Fields::Unnamed(_) => unreachable!(), // already checked
};
let left = self.ats.get(i).unwrap();
quote! {
#left => ::std::option::Option::Some(#right)
}
});
quote! {
fn from_path(path: &str, params: &::std::collections::HashMap<&str, &str>) -> ::std::option::Option<Self> {
match path {
#(#from_path_matches),*,
_ => ::std::option::Option::None,
}
}
}
}
fn build_to_path(&self) -> TokenStream {
let to_path_matches = self.variants.iter().enumerate().map(|(i, variant)| {
let ident = &variant.ident;
let mut right = self.ats.get(i).unwrap().value();
match &variant.fields {
Fields::Unit => quote! { Self::#ident => ::std::string::ToString::to_string(#right) },
Fields::Named(field) => {
let fields = field
.named
.iter()
.map(|it| it.ident.as_ref().unwrap())
.collect::<Vec<_>>();
for field in fields.iter() {
// :param -> {param}
// *param -> {param}
// so we can pass it to `format!("...", param)`
right = right.replace(&format!(":{field}"), &format!("{{{field}}}"));
right = right.replace(&format!("*{field}"), &format!("{{{field}}}"));
}
quote! {
Self::#ident { #(#fields),* } => ::std::format!(#right, #(#fields = ::yew_router::__macro::encode_for_url(&::std::format!("{}", #fields))),*)
}
}
Fields::Unnamed(_) => unreachable!(), // already checked
}
});
quote! {
fn to_path(&self) -> ::std::string::String {
match self {
#(#to_path_matches),*,
}
}
}
}
}
pub fn routable_derive_impl(input: Routable) -> TokenStream {
let Routable {
ats,
not_found_route,
ident,
..
} = &input;
let from_path = input.build_from_path();
let to_path = input.build_to_path();
let maybe_not_found_route = match not_found_route {
Some(route) => quote! { ::std::option::Option::Some(Self::#route) },
None => quote! { ::std::option::Option::None },
};
let maybe_default = match not_found_route {
Some(route) => {
quote! {
impl ::std::default::Default for #ident {
fn default() -> Self {
Self::#route
}
}
}
}
None => TokenStream::new(),
};
quote! {
#[automatically_derived]
impl ::yew_router::Routable for #ident {
#from_path
#to_path
fn routes() -> ::std::vec::Vec<&'static str> {
::std::vec![#(#ats),*]
}
fn not_found_route() -> ::std::option::Option<Self> {
#maybe_not_found_route
}
fn recognize(pathname: &str) -> ::std::option::Option<Self> {
::std::thread_local! {
static ROUTER: ::yew_router::__macro::Router = ::yew_router::__macro::build_router::<#ident>();
}
ROUTER.with(|router| ::yew_router::__macro::recognize_with_router(router, pathname))
}
}
#maybe_default
}
}