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#![cfg_attr(not(feature = "std"), no_std)]
use frame_support::traits::FindAuthor;
use sp_std::prelude::*;
pub use pallet::*;
#[impl_trait_for_tuples::impl_for_tuples(30)]
pub trait EventHandler<Author, BlockNumber> {
fn note_author(author: Author);
}
#[frame_support::pallet]
pub mod pallet {
use super::*;
use frame_support::pallet_prelude::*;
use frame_system::pallet_prelude::*;
#[pallet::config]
pub trait Config: frame_system::Config {
type FindAuthor: FindAuthor<Self::AccountId>;
type EventHandler: EventHandler<Self::AccountId, Self::BlockNumber>;
}
#[pallet::pallet]
pub struct Pallet<T>(_);
#[pallet::hooks]
impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
fn on_initialize(_: T::BlockNumber) -> Weight {
if let Some(author) = Self::author() {
T::EventHandler::note_author(author);
}
Weight::zero()
}
fn on_finalize(_: T::BlockNumber) {
<Author<T>>::kill();
}
}
#[pallet::storage]
pub(super) type Author<T: Config> = StorageValue<_, T::AccountId, OptionQuery>;
}
impl<T: Config> Pallet<T> {
pub fn author() -> Option<T::AccountId> {
if let Some(author) = <Author<T>>::get() {
return Some(author)
}
let digest = <frame_system::Pallet<T>>::digest();
let pre_runtime_digests = digest.logs.iter().filter_map(|d| d.as_pre_runtime());
T::FindAuthor::find_author(pre_runtime_digests).map(|a| {
<Author<T>>::put(&a);
a
})
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate as pallet_authorship;
use codec::{Decode, Encode};
use frame_support::{
traits::{ConstU32, ConstU64},
ConsensusEngineId,
};
use sp_core::H256;
use sp_runtime::{
generic::DigestItem,
testing::Header,
traits::{BlakeTwo256, Header as HeaderT, IdentityLookup},
};
type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
type Block = frame_system::mocking::MockBlock<Test>;
frame_support::construct_runtime!(
pub enum Test where
Block = Block,
NodeBlock = Block,
UncheckedExtrinsic = UncheckedExtrinsic,
{
System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
Authorship: pallet_authorship::{Pallet, Storage},
}
);
impl frame_system::Config for Test {
type BaseCallFilter = frame_support::traits::Everything;
type BlockWeights = ();
type BlockLength = ();
type DbWeight = ();
type RuntimeOrigin = RuntimeOrigin;
type Index = u64;
type BlockNumber = u64;
type RuntimeCall = RuntimeCall;
type Hash = H256;
type Hashing = BlakeTwo256;
type AccountId = u64;
type Lookup = IdentityLookup<Self::AccountId>;
type Header = Header;
type RuntimeEvent = RuntimeEvent;
type BlockHashCount = ConstU64<250>;
type Version = ();
type PalletInfo = PalletInfo;
type AccountData = ();
type OnNewAccount = ();
type OnKilledAccount = ();
type SystemWeightInfo = ();
type SS58Prefix = ();
type OnSetCode = ();
type MaxConsumers = ConstU32<16>;
}
impl pallet::Config for Test {
type FindAuthor = AuthorGiven;
type EventHandler = ();
}
const TEST_ID: ConsensusEngineId = [1, 2, 3, 4];
pub struct AuthorGiven;
impl FindAuthor<u64> for AuthorGiven {
fn find_author<'a, I>(digests: I) -> Option<u64>
where
I: 'a + IntoIterator<Item = (ConsensusEngineId, &'a [u8])>,
{
for (id, mut data) in digests {
if id == TEST_ID {
return u64::decode(&mut data).ok()
}
}
None
}
}
fn seal_header(mut header: Header, author: u64) -> Header {
{
let digest = header.digest_mut();
digest.logs.push(DigestItem::PreRuntime(TEST_ID, author.encode()));
digest.logs.push(DigestItem::Seal(TEST_ID, author.encode()));
}
header
}
fn create_header(number: u64, parent_hash: H256, state_root: H256) -> Header {
Header::new(number, Default::default(), state_root, parent_hash, Default::default())
}
fn new_test_ext() -> sp_io::TestExternalities {
let t = frame_system::GenesisConfig::default().build_storage::<Test>().unwrap();
t.into()
}
#[test]
fn sets_author_lazily() {
new_test_ext().execute_with(|| {
let author = 42;
let mut header =
seal_header(create_header(1, Default::default(), [1; 32].into()), author);
header.digest_mut().pop(); System::reset_events();
System::initialize(&1, &Default::default(), header.digest());
assert_eq!(Authorship::author(), Some(author));
});
}
}