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use crate::construct_runtime::Pallet;
use proc_macro2::TokenStream;
use quote::quote;
use std::str::FromStr;
use syn::{Generics, Ident};
pub fn expand_outer_event(
runtime: &Ident,
pallet_decls: &[Pallet],
scrate: &TokenStream,
) -> syn::Result<TokenStream> {
let mut event_variants = TokenStream::new();
let mut event_conversions = TokenStream::new();
let mut query_event_part_macros = Vec::new();
for pallet_decl in pallet_decls {
if let Some(pallet_entry) = pallet_decl.find_part("Event") {
let path = &pallet_decl.path;
let pallet_name = &pallet_decl.name;
let index = pallet_decl.index;
let instance = pallet_decl.instance.as_ref();
let generics = &pallet_entry.generics;
if instance.is_some() && generics.params.is_empty() {
let msg = format!(
"Instantiable pallet with no generic `Event` cannot \
be constructed: pallet `{}` must have generic `Event`",
pallet_name,
);
return Err(syn::Error::new(pallet_name.span(), msg))
}
let part_is_generic = !generics.params.is_empty();
let pallet_event = match (instance, part_is_generic) {
(Some(inst), true) => quote!(#path::Event::<#runtime, #path::#inst>),
(Some(inst), false) => quote!(#path::Event::<#path::#inst>),
(None, true) => quote!(#path::Event::<#runtime>),
(None, false) => quote!(#path::Event),
};
event_variants.extend(expand_event_variant(
runtime,
pallet_decl,
index,
instance,
generics,
));
event_conversions.extend(expand_event_conversion(scrate, pallet_decl, &pallet_event));
query_event_part_macros.push(quote! {
#path::__substrate_event_check::is_event_part_defined!(#pallet_name);
});
}
}
Ok(quote! {
#( #query_event_part_macros )*
#[derive(
Clone, PartialEq, Eq,
#scrate::codec::Encode,
#scrate::codec::Decode,
#scrate::scale_info::TypeInfo,
#scrate::RuntimeDebug,
)]
#[allow(non_camel_case_types)]
pub enum Event {
#event_variants
}
#event_conversions
})
}
fn expand_event_variant(
runtime: &Ident,
pallet: &Pallet,
index: u8,
instance: Option<&Ident>,
generics: &Generics,
) -> TokenStream {
let path = &pallet.path;
let variant_name = &pallet.name;
let part_is_generic = !generics.params.is_empty();
let attr = pallet.cfg_pattern.iter().fold(TokenStream::new(), |acc, pattern| {
let attr = TokenStream::from_str(&format!("#[cfg({})]", pattern.original()))
.expect("was successfully parsed before; qed");
quote! {
#acc
#attr
}
});
match instance {
Some(inst) if part_is_generic => quote! {
#attr
#[codec(index = #index)]
#variant_name(#path::Event<#runtime, #path::#inst>),
},
Some(inst) => quote! {
#attr
#[codec(index = #index)]
#variant_name(#path::Event<#path::#inst>),
},
None if part_is_generic => quote! {
#attr
#[codec(index = #index)]
#variant_name(#path::Event<#runtime>),
},
None => quote! {
#attr
#[codec(index = #index)]
#variant_name(#path::Event),
},
}
}
fn expand_event_conversion(
scrate: &TokenStream,
pallet: &Pallet,
pallet_event: &TokenStream,
) -> TokenStream {
let variant_name = &pallet.name;
let attr = pallet.cfg_pattern.iter().fold(TokenStream::new(), |acc, pattern| {
let attr = TokenStream::from_str(&format!("#[cfg({})]", pattern.original()))
.expect("was successfully parsed before; qed");
quote! {
#acc
#attr
}
});
quote! {
#attr
impl From<#pallet_event> for Event {
fn from(x: #pallet_event) -> Self {
Event::#variant_name(x)
}
}
#attr
impl TryInto<#pallet_event> for Event {
type Error = ();
fn try_into(self) -> #scrate::sp_std::result::Result<#pallet_event, Self::Error> {
match self {
Self::#variant_name(evt) => Ok(evt),
_ => Err(()),
}
}
}
}
}