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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 alloc::{vec, vec::Vec};
use codec::{Decode, Encode};
use scale_info::TypeInfo;
use sp_runtime::traits::Block;
/// Id of different payloads in the [`crate::Commitment`] data.
pub type BeefyPayloadId = [u8; 2];
/// Registry of all known [`BeefyPayloadId`].
pub mod known_payloads {
use crate::BeefyPayloadId;
/// A [`Payload`](super::Payload) identifier for Merkle Mountain Range root hash.
///
/// Encoded value should contain a [`crate::MmrRootHash`] type (i.e. 32-bytes hash).
pub const MMR_ROOT_ID: BeefyPayloadId = *b"mh";
}
/// A BEEFY payload type allowing for future extensibility of adding additional kinds of payloads.
///
/// The idea is to store a vector of SCALE-encoded values with an extra identifier.
/// Identifiers MUST be sorted by the [`BeefyPayloadId`] to allow efficient lookup of expected
/// value. Duplicated identifiers are disallowed. It's okay for different implementations to only
/// support a subset of possible values.
#[derive(Decode, Encode, Debug, PartialEq, Eq, Clone, Ord, PartialOrd, Hash, TypeInfo)]
pub struct Payload(Vec<(BeefyPayloadId, Vec<u8>)>);
impl Payload {
/// Construct a new payload given an initial value
pub fn from_single_entry(id: BeefyPayloadId, value: Vec<u8>) -> Self {
Self(vec![(id, value)])
}
/// Returns a raw payload under given `id`.
///
/// If the [`BeefyPayloadId`] is not found in the payload `None` is returned.
pub fn get_raw(&self, id: &BeefyPayloadId) -> Option<&Vec<u8>> {
let index = self.0.binary_search_by(|probe| probe.0.cmp(id)).ok()?;
Some(&self.0[index].1)
}
/// Returns all the raw payloads under given `id`.
pub fn get_all_raw<'a>(
&'a self,
id: &'a BeefyPayloadId,
) -> impl Iterator<Item = &Vec<u8>> + 'a {
self.0
.iter()
.filter_map(move |probe| if &probe.0 != id { return None } else { Some(&probe.1) })
}
/// Returns a decoded payload value under given `id`.
///
/// In case the value is not there, or it cannot be decoded `None` is returned.
pub fn get_decoded<T: Decode>(&self, id: &BeefyPayloadId) -> Option<T> {
self.get_raw(id).and_then(|raw| T::decode(&mut &raw[..]).ok())
}
/// Returns all decoded payload values under given `id`.
pub fn get_all_decoded<'a, T: Decode>(
&'a self,
id: &'a BeefyPayloadId,
) -> impl Iterator<Item = Option<T>> + 'a {
self.get_all_raw(id).map(|raw| T::decode(&mut &raw[..]).ok())
}
/// Push a `Vec<u8>` with a given id into the payload vec.
/// This method will internally sort the payload vec after every push.
///
/// Returns self to allow for daisy chaining.
pub fn push_raw(mut self, id: BeefyPayloadId, value: Vec<u8>) -> Self {
self.0.push((id, value));
self.0.sort_by_key(|(id, _)| *id);
self
}
}
/// Trait for custom BEEFY payload providers.
pub trait PayloadProvider<B: Block> {
/// Provide BEEFY payload if available for `header`.
fn payload(&self, header: &B::Header) -> Option<Payload>;
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn payload_methods_work_as_expected() {
let id1: BeefyPayloadId = *b"hw";
let msg1: String = "1. Hello World!".to_string();
let id2: BeefyPayloadId = *b"yb";
let msg2: String = "2. Yellow Board!".to_string();
let id3: BeefyPayloadId = *b"cs";
let msg3: String = "3. Cello Cord!".to_string();
let payload = Payload::from_single_entry(id1, msg1.encode())
.push_raw(id2, msg2.encode())
.push_raw(id3, msg3.encode());
assert_eq!(payload.get_decoded(&id1), Some(msg1));
assert_eq!(payload.get_decoded(&id2), Some(msg2));
assert_eq!(payload.get_raw(&id3), Some(&msg3.encode()));
assert_eq!(payload.get_raw(&known_payloads::MMR_ROOT_ID), None);
}
}