1// This file is part of Substrate.
23// Copyright (C) Parity Technologies (UK) Ltd.
4// SPDX-License-Identifier: Apache-2.0
56// Licensed under the Apache License, Version 2.0 (the "License");
7// you may not use this file except in compliance with the License.
8// You may obtain a copy of the License at
9//
10// http://www.apache.org/licenses/LICENSE-2.0
11//
12// Unless required by applicable law or agreed to in writing, software
13// distributed under the License is distributed on an "AS IS" BASIS,
14// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15// See the License for the specific language governing permissions and
16// limitations under the License.
1718use super::helper;
19use syn::spanned::Spanned;
2021/// Implementation of the pallet hooks.
22pub struct HooksDef {
23/// A set of usage of instance, must be check for consistency with trait.
24pub instances: Vec<helper::InstanceUsage>,
25/// The where_clause used.
26pub where_clause: Option<syn::WhereClause>,
27/// The span of the pallet::hooks attribute.
28pub attr_span: proc_macro2::Span,
29/// Boolean flag, set to true if the `on_runtime_upgrade` method of hooks was implemented.
30pub has_runtime_upgrade: bool,
31}
3233impl HooksDef {
34pub fn try_from(attr_span: proc_macro2::Span, item: &mut syn::Item) -> syn::Result<Self> {
35let item = if let syn::Item::Impl(item) = item {
36 item
37 } else {
38let msg = "Invalid pallet::hooks, expected item impl";
39return Err(syn::Error::new(item.span(), msg))
40 };
4142let instances = vec![
43 helper::check_pallet_struct_usage(&item.self_ty)?,
44 helper::check_impl_gen(&item.generics, item.impl_token.span())?,
45 ];
4647let item_trait = &item
48 .trait_
49 .as_ref()
50 .ok_or_else(|| {
51let msg = "Invalid pallet::hooks, expected impl<..> Hooks \
52 for Pallet<..>";
53 syn::Error::new(item.span(), msg)
54 })?
55.1;
5657if item_trait.segments.len() != 1 || item_trait.segments[0].ident != "Hooks" {
58let msg = format!(
59"Invalid pallet::hooks, expected trait to be `Hooks` found `{}`\
60 , you can import from `frame_support::pallet_prelude`",
61quote::quote!(#item_trait)
62 );
6364return Err(syn::Error::new(item_trait.span(), msg))
65 }
6667let has_runtime_upgrade = item.items.iter().any(|i| match i {
68 syn::ImplItem::Fn(method) => method.sig.ident == "on_runtime_upgrade",
69_ => false,
70 });
7172Ok(Self {
73 attr_span,
74 instances,
75 has_runtime_upgrade,
76 where_clause: item.generics.where_clause.clone(),
77 })
78 }
79}