frame_support_procedural/pallet/parse/
hooks.rs

1// This file is part of Substrate.
2
3// Copyright (C) Parity Technologies (UK) Ltd.
4// SPDX-License-Identifier: Apache-2.0
5
6// 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.
17
18use super::helper;
19use syn::spanned::Spanned;
20
21/// Implementation of the pallet hooks.
22pub struct HooksDef {
23	/// A set of usage of instance, must be check for consistency with trait.
24	pub instances: Vec<helper::InstanceUsage>,
25	/// The where_clause used.
26	pub where_clause: Option<syn::WhereClause>,
27	/// The span of the pallet::hooks attribute.
28	pub attr_span: proc_macro2::Span,
29	/// Boolean flag, set to true if the `on_runtime_upgrade` method of hooks was implemented.
30	pub has_runtime_upgrade: bool,
31}
32
33impl HooksDef {
34	pub fn try_from(attr_span: proc_macro2::Span, item: &mut syn::Item) -> syn::Result<Self> {
35		let item = if let syn::Item::Impl(item) = item {
36			item
37		} else {
38			let msg = "Invalid pallet::hooks, expected item impl";
39			return Err(syn::Error::new(item.span(), msg))
40		};
41
42		let instances = vec![
43			helper::check_pallet_struct_usage(&item.self_ty)?,
44			helper::check_impl_gen(&item.generics, item.impl_token.span())?,
45		];
46
47		let item_trait = &item
48			.trait_
49			.as_ref()
50			.ok_or_else(|| {
51				let msg = "Invalid pallet::hooks, expected impl<..> Hooks \
52					for Pallet<..>";
53				syn::Error::new(item.span(), msg)
54			})?
55			.1;
56
57		if item_trait.segments.len() != 1 || item_trait.segments[0].ident != "Hooks" {
58			let msg = format!(
59				"Invalid pallet::hooks, expected trait to be `Hooks` found `{}`\
60				, you can import from `frame_support::pallet_prelude`",
61				quote::quote!(#item_trait)
62			);
63
64			return Err(syn::Error::new(item_trait.span(), msg))
65		}
66
67		let has_runtime_upgrade = item.items.iter().any(|i| match i {
68			syn::ImplItem::Fn(method) => method.sig.ident == "on_runtime_upgrade",
69			_ => false,
70		});
71
72		Ok(Self {
73			attr_span,
74			instances,
75			has_runtime_upgrade,
76			where_clause: item.generics.where_clause.clone(),
77		})
78	}
79}
frame_support_procedural/pallet/parse/hooks.rs

frame_support_procedural/pallet/parse/
hooks.rs
