use crate::pallet::Def;
struct ConstDef {
pub ident: syn::Ident,
pub type_: syn::Type,
pub doc: Vec<syn::Expr>,
pub default_byte_impl: proc_macro2::TokenStream,
pub metadata_name: Option<syn::Ident>,
pub deprecation_info: proc_macro2::TokenStream,
}
pub fn expand_constants(def: &mut Def) -> proc_macro2::TokenStream {
let frame_support = &def.frame_support;
let type_impl_gen = &def.type_impl_generics(proc_macro2::Span::call_site());
let type_use_gen = &def.type_use_generics(proc_macro2::Span::call_site());
let pallet_ident = &def.pallet_struct.pallet;
let trait_use_gen = &def.trait_use_generics(proc_macro2::Span::call_site());
let mut where_clauses = vec![&def.config.where_clause];
where_clauses.extend(def.extra_constants.iter().map(|d| &d.where_clause));
let completed_where_clause = super::merge_where_clauses(&where_clauses);
let mut config_consts = vec![];
for const_ in def.config.consts_metadata.iter() {
let ident = &const_.ident;
let const_type = &const_.type_;
let deprecation_info = match crate::deprecation::get_deprecation(
"e::quote! { #frame_support },
&const_.attrs,
) {
Ok(deprecation) => deprecation,
Err(e) => return e.into_compile_error(),
};
config_consts.push(ConstDef {
ident: const_.ident.clone(),
type_: const_.type_.clone(),
doc: const_.doc.clone(),
default_byte_impl: quote::quote!(
let value = <<T as Config #trait_use_gen>::#ident as
#frame_support::traits::Get<#const_type>>::get();
#frame_support::__private::codec::Encode::encode(&value)
),
metadata_name: None,
deprecation_info,
})
}
let mut extra_consts = vec![];
for const_ in def.extra_constants.iter().flat_map(|d| &d.extra_constants) {
let ident = &const_.ident;
let deprecation_info = match crate::deprecation::get_deprecation(
"e::quote! { #frame_support },
&const_.attrs,
) {
Ok(deprecation) => deprecation,
Err(e) => return e.into_compile_error(),
};
extra_consts.push(ConstDef {
ident: const_.ident.clone(),
type_: const_.type_.clone(),
doc: const_.doc.clone(),
default_byte_impl: quote::quote!(
let value = <Pallet<#type_use_gen>>::#ident();
#frame_support::__private::codec::Encode::encode(&value)
),
metadata_name: const_.metadata_name.clone(),
deprecation_info,
})
}
let consts = config_consts.into_iter().chain(extra_consts.into_iter()).map(|const_| {
let const_type = &const_.type_;
let ident_str = format!("{}", const_.metadata_name.unwrap_or(const_.ident));
let no_docs = vec![];
let doc = if cfg!(feature = "no-metadata-docs") { &no_docs } else { &const_.doc };
let default_byte_impl = &const_.default_byte_impl;
let deprecation_info = &const_.deprecation_info;
quote::quote!({
#frame_support::__private::metadata_ir::PalletConstantMetadataIR {
name: #ident_str,
ty: #frame_support::__private::scale_info::meta_type::<#const_type>(),
value: { #default_byte_impl },
docs: #frame_support::__private::vec![ #( #doc ),* ],
deprecation_info: #deprecation_info
}
})
});
quote::quote!(
impl<#type_impl_gen> #pallet_ident<#type_use_gen> #completed_where_clause{
#[doc(hidden)]
pub fn pallet_constants_metadata()
-> #frame_support::__private::Vec<#frame_support::__private::metadata_ir::PalletConstantMetadataIR>
{
#frame_support::__private::vec![ #( #consts ),* ]
}
}
)
}