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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.
//! Implementation for pallet attribute macro.
//!
//! General workflow:
//! 1 - parse all pallet attributes:
//! This step remove all attributes `#[pallet::*]` from the ItemMod and build the `Def` struct
//! which holds the ItemMod without `#[pallet::*]` and information given by those attributes
//! 2 - expand from the parsed information
//! This step will modify the ItemMod by adding some derive attributes or phantom data variants
//! to user defined types. And also crate new types and implement block.
mod expand;
pub(crate) mod parse;
pub use parse::{composite::keyword::CompositeKeyword, Def};
use syn::spanned::Spanned;
mod keyword {
syn::custom_keyword!(dev_mode);
}
pub fn pallet(
attr: proc_macro::TokenStream,
item: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
let mut dev_mode = false;
if !attr.is_empty() {
if let Ok(_) = syn::parse::<keyword::dev_mode>(attr.clone()) {
dev_mode = true;
} else {
let msg = "Invalid pallet macro call: unexpected attribute. Macro call must be \
bare, such as `#[frame_support::pallet]` or `#[pallet]`, or must specify the \
`dev_mode` attribute, such as `#[frame_support::pallet(dev_mode)]` or \
#[pallet(dev_mode)].";
let span = proc_macro2::TokenStream::from(attr).span();
return syn::Error::new(span, msg).to_compile_error().into()
}
}
let item = syn::parse_macro_input!(item as syn::ItemMod);
match parse::Def::try_from(item, dev_mode) {
Ok(def) => expand::expand(def).into(),
Err(e) => e.to_compile_error().into(),
}
}