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// This file is part of Substrate.
// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use super::helper;
use syn::spanned::Spanned;
/// Definition for pallet genesis build implementation.
pub struct GenesisBuildDef {
/// A set of usage of instance, must be check for consistency with trait.
pub instances: Option<Vec<helper::InstanceUsage>>,
/// The where_clause used.
pub where_clause: Option<syn::WhereClause>,
/// The span of the pallet::genesis_build attribute.
pub attr_span: proc_macro2::Span,
}
impl GenesisBuildDef {
pub fn try_from(attr_span: proc_macro2::Span, item: &mut syn::Item) -> syn::Result<Self> {
let item = if let syn::Item::Impl(item) = item {
item
} else {
let msg = "Invalid pallet::genesis_build, expected item impl";
return Err(syn::Error::new(item.span(), msg))
};
let item_trait = &item
.trait_
.as_ref()
.ok_or_else(|| {
let msg = "Invalid pallet::genesis_build, expected impl<..> GenesisBuild<..> \
for GenesisConfig<..>";
syn::Error::new(item.span(), msg)
})?
.1;
let instances =
helper::check_genesis_builder_usage(item_trait)?.map(|instances| vec![instances]);
Ok(Self { attr_span, instances, where_clause: item.generics.where_clause.clone() })
}
}