pallet-statement 30.0.0

// 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.

//! Supporting pallet for the statement store.
//!
//! - [`Pallet`]
//!
//! ## Overview
//!
//! The Statement pallet provides means to create statements for the statement store.
//!
//! This pallet contains an offchain worker that turns on-chain statement events into
//! statements. These statements are placed in the store and propagated over the network.

#![cfg_attr(not(feature = "std"), no_std)]

use frame_support::{pallet_prelude::*, traits::fungible::Inspect};
use frame_system::pallet_prelude::*;
use sp_statement_store::Statement;

pub use pallet::*;

const LOG_TARGET: &str = "runtime::statement";

#[frame_support::pallet]
pub mod pallet {
	use super::*;

	pub type BalanceOf<T> =
		<<T as Config>::Currency as Inspect<<T as frame_system::Config>::AccountId>>::Balance;

	pub type AccountIdOf<T> = <T as frame_system::Config>::AccountId;

	#[pallet::config]
	pub trait Config: frame_system::Config
	where
		<Self as frame_system::Config>::AccountId: From<sp_statement_store::AccountId>,
	{
		/// The overarching event type.
		#[allow(deprecated)]
		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
		/// The currency which is used to calculate account limits.
		type Currency: Inspect<Self::AccountId>;
		/// Min balance for priority statements.
		#[pallet::constant]
		type StatementCost: Get<BalanceOf<Self>>;
		/// Cost of data byte used for priority calculation.
		#[pallet::constant]
		type ByteCost: Get<BalanceOf<Self>>;
		/// Minimum number of statements allowed per account.
		#[pallet::constant]
		type MinAllowedStatements: Get<u32>;
		/// Maximum number of statements allowed per account.
		#[pallet::constant]
		type MaxAllowedStatements: Get<u32>;
		/// Minimum data bytes allowed per account.
		#[pallet::constant]
		type MinAllowedBytes: Get<u32>;
		/// Maximum data bytes allowed per account.
		#[pallet::constant]
		type MaxAllowedBytes: Get<u32>;
	}

	#[pallet::pallet]
	pub struct Pallet<T>(core::marker::PhantomData<T>);

	#[pallet::event]
	#[pallet::generate_deposit(pub(super) fn deposit_event)]
	pub enum Event<T: Config>
	where
		<T as frame_system::Config>::AccountId: From<sp_statement_store::AccountId>,
	{
		/// A new statement is submitted
		NewStatement { account: T::AccountId, statement: Statement },
	}

	#[pallet::hooks]
	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T>
	where
		<T as frame_system::Config>::AccountId: From<sp_statement_store::AccountId>,
		sp_statement_store::AccountId: From<<T as frame_system::Config>::AccountId>,
		<T as frame_system::Config>::RuntimeEvent: From<pallet::Event<T>>,
		<T as frame_system::Config>::RuntimeEvent: TryInto<pallet::Event<T>>,
		sp_statement_store::BlockHash: From<<T as frame_system::Config>::Hash>,
	{
		fn offchain_worker(now: BlockNumberFor<T>) {
			log::trace!(target: LOG_TARGET, "Collecting statements at #{:?}", now);
			Pallet::<T>::collect_statements();
		}
	}
}

impl<T: Config> Pallet<T>
where
	<T as frame_system::Config>::AccountId: From<sp_statement_store::AccountId>,
	sp_statement_store::AccountId: From<<T as frame_system::Config>::AccountId>,
	<T as frame_system::Config>::RuntimeEvent: From<pallet::Event<T>>,
	<T as frame_system::Config>::RuntimeEvent: TryInto<pallet::Event<T>>,
	sp_statement_store::BlockHash: From<<T as frame_system::Config>::Hash>,
{
	/// Submit a statement event. The statement will be picked up by the offchain worker and
	/// broadcast to the network.
	pub fn submit_statement(account: T::AccountId, statement: Statement) {
		Self::deposit_event(Event::NewStatement { account, statement });
	}

	fn collect_statements() {
		for event in frame_system::Pallet::<T>::read_events_no_consensus() {
			if let Ok(Event::<T>::NewStatement { account: _, statement }) = event.event.try_into() {
				sp_statement_store::runtime_api::statement_store::submit_statement(statement);
			}
		}
	}
}