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// This file is part of Substrate.
// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
//! Block import helpers.
use serde::{Deserialize, Serialize};
use sp_runtime::{
traits::{Block as BlockT, HashingFor, Header as HeaderT, NumberFor},
DigestItem, Justification, Justifications,
};
use std::{any::Any, borrow::Cow, collections::HashMap, sync::Arc};
use sp_consensus::{BlockOrigin, Error};
/// Block import result.
#[derive(Debug, PartialEq, Eq)]
pub enum ImportResult {
/// Block imported.
Imported(ImportedAux),
/// Already in the blockchain.
AlreadyInChain,
/// Block or parent is known to be bad.
KnownBad,
/// Block parent is not in the chain.
UnknownParent,
/// Parent state is missing.
MissingState,
}
/// Auxiliary data associated with an imported block result.
#[derive(Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
pub struct ImportedAux {
/// Only the header has been imported. Block body verification was skipped.
pub header_only: bool,
/// Clear all pending justification requests.
pub clear_justification_requests: bool,
/// Request a justification for the given block.
pub needs_justification: bool,
/// Received a bad justification.
pub bad_justification: bool,
/// Whether the block that was imported is the new best block.
pub is_new_best: bool,
}
impl ImportResult {
/// Returns default value for `ImportResult::Imported` with
/// `clear_justification_requests`, `needs_justification`,
/// `bad_justification` set to false.
pub fn imported(is_new_best: bool) -> ImportResult {
let aux = ImportedAux { is_new_best, ..Default::default() };
ImportResult::Imported(aux)
}
/// Handles any necessary request for justifications (or clearing of pending requests) based on
/// the outcome of this block import.
pub fn handle_justification<B>(
&self,
hash: &B::Hash,
number: NumberFor<B>,
justification_sync_link: &dyn JustificationSyncLink<B>,
) where
B: BlockT,
{
match self {
ImportResult::Imported(aux) => {
if aux.clear_justification_requests {
justification_sync_link.clear_justification_requests();
}
if aux.needs_justification {
justification_sync_link.request_justification(hash, number);
}
},
_ => {},
}
}
}
/// Fork choice strategy.
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub enum ForkChoiceStrategy {
/// Longest chain fork choice.
LongestChain,
/// Custom fork choice rule, where true indicates the new block should be the best block.
Custom(bool),
}
/// Data required to check validity of a Block.
#[derive(Debug, PartialEq, Eq, Clone)]
pub struct BlockCheckParams<Block: BlockT> {
/// Hash of the block that we verify.
pub hash: Block::Hash,
/// Block number of the block that we verify.
pub number: NumberFor<Block>,
/// Parent hash of the block that we verify.
pub parent_hash: Block::Hash,
/// Allow importing the block skipping state verification if parent state is missing.
pub allow_missing_state: bool,
/// Allow importing the block if parent block is missing.
pub allow_missing_parent: bool,
/// Re-validate existing block.
pub import_existing: bool,
}
/// Precomputed storage.
pub enum StorageChanges<Block: BlockT> {
/// Changes coming from block execution.
Changes(sp_state_machine::StorageChanges<HashingFor<Block>>),
/// Whole new state.
Import(ImportedState<Block>),
}
/// Imported state data. A vector of key-value pairs that should form a trie.
#[derive(PartialEq, Eq, Clone)]
pub struct ImportedState<B: BlockT> {
/// Target block hash.
pub block: B::Hash,
/// State keys and values.
pub state: sp_state_machine::KeyValueStates,
}
impl<B: BlockT> std::fmt::Debug for ImportedState<B> {
fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
fmt.debug_struct("ImportedState").field("block", &self.block).finish()
}
}
/// Defines how a new state is computed for a given imported block.
pub enum StateAction<Block: BlockT> {
/// Apply precomputed changes coming from block execution or state sync.
ApplyChanges(StorageChanges<Block>),
/// Execute block body (required) and compute state.
Execute,
/// Execute block body if parent state is available and compute state.
ExecuteIfPossible,
/// Don't execute or import state.
Skip,
}
impl<Block: BlockT> StateAction<Block> {
/// Check if execution checks that require runtime calls should be skipped.
pub fn skip_execution_checks(&self) -> bool {
match self {
StateAction::ApplyChanges(_) |
StateAction::Execute |
StateAction::ExecuteIfPossible => false,
StateAction::Skip => true,
}
}
}
/// Data required to import a Block.
#[non_exhaustive]
pub struct BlockImportParams<Block: BlockT> {
/// Origin of the Block
pub origin: BlockOrigin,
/// The header, without consensus post-digests applied. This should be in the same
/// state as it comes out of the runtime.
///
/// Consensus engines which alter the header (by adding post-runtime digests)
/// should strip those off in the initial verification process and pass them
/// via the `post_digests` field. During block authorship, they should
/// not be pushed to the header directly.
///
/// The reason for this distinction is so the header can be directly
/// re-executed in a runtime that checks digest equivalence -- the
/// post-runtime digests are pushed back on after.
pub header: Block::Header,
/// Justification(s) provided for this block from the outside.
pub justifications: Option<Justifications>,
/// Digest items that have been added after the runtime for external
/// work, like a consensus signature.
pub post_digests: Vec<DigestItem>,
/// The body of the block.
pub body: Option<Vec<Block::Extrinsic>>,
/// Indexed transaction body of the block.
pub indexed_body: Option<Vec<Vec<u8>>>,
/// Specify how the new state is computed.
pub state_action: StateAction<Block>,
/// Is this block finalized already?
/// `true` implies instant finality.
pub finalized: bool,
/// Intermediate values that are interpreted by block importers. Each block importer,
/// upon handling a value, removes it from the intermediate list. The final block importer
/// rejects block import if there are still intermediate values that remain unhandled.
pub intermediates: HashMap<Cow<'static, [u8]>, Box<dyn Any + Send>>,
/// Auxiliary consensus data produced by the block.
/// Contains a list of key-value pairs. If values are `None`, the keys will be deleted. These
/// changes will be applied to `AuxStore` database all as one batch, which is more efficient
/// than updating `AuxStore` directly.
pub auxiliary: Vec<(Vec<u8>, Option<Vec<u8>>)>,
/// Fork choice strategy of this import. This should only be set by a
/// synchronous import, otherwise it may race against other imports.
/// `None` indicates that the current verifier or importer cannot yet
/// determine the fork choice value, and it expects subsequent importer
/// to modify it. If `None` is passed all the way down to bottom block
/// importer, the import fails with an `IncompletePipeline` error.
pub fork_choice: Option<ForkChoiceStrategy>,
/// Re-validate existing block.
pub import_existing: bool,
/// Cached full header hash (with post-digests applied).
pub post_hash: Option<Block::Hash>,
}
impl<Block: BlockT> BlockImportParams<Block> {
/// Create a new block import params.
pub fn new(origin: BlockOrigin, header: Block::Header) -> Self {
Self {
origin,
header,
justifications: None,
post_digests: Vec::new(),
body: None,
indexed_body: None,
state_action: StateAction::Execute,
finalized: false,
intermediates: HashMap::new(),
auxiliary: Vec::new(),
fork_choice: None,
import_existing: false,
post_hash: None,
}
}
/// Get the full header hash (with post-digests applied).
pub fn post_hash(&self) -> Block::Hash {
if let Some(hash) = self.post_hash {
hash
} else {
self.post_header().hash()
}
}
/// Get the post header.
pub fn post_header(&self) -> Block::Header {
if self.post_digests.is_empty() {
self.header.clone()
} else {
let mut hdr = self.header.clone();
for digest_item in &self.post_digests {
hdr.digest_mut().push(digest_item.clone());
}
hdr
}
}
/// Insert intermediate by given key.
pub fn insert_intermediate<T: 'static + Send>(&mut self, key: &'static [u8], value: T) {
self.intermediates.insert(Cow::from(key), Box::new(value));
}
/// Remove and return intermediate by given key.
pub fn remove_intermediate<T: 'static>(&mut self, key: &[u8]) -> Result<T, Error> {
let (k, v) = self.intermediates.remove_entry(key).ok_or(Error::NoIntermediate)?;
v.downcast::<T>().map(|v| *v).map_err(|v| {
self.intermediates.insert(k, v);
Error::InvalidIntermediate
})
}
/// Get a reference to a given intermediate.
pub fn get_intermediate<T: 'static>(&self, key: &[u8]) -> Result<&T, Error> {
self.intermediates
.get(key)
.ok_or(Error::NoIntermediate)?
.downcast_ref::<T>()
.ok_or(Error::InvalidIntermediate)
}
/// Get a mutable reference to a given intermediate.
pub fn get_intermediate_mut<T: 'static>(&mut self, key: &[u8]) -> Result<&mut T, Error> {
self.intermediates
.get_mut(key)
.ok_or(Error::NoIntermediate)?
.downcast_mut::<T>()
.ok_or(Error::InvalidIntermediate)
}
/// Check if this block contains state import action
pub fn with_state(&self) -> bool {
matches!(self.state_action, StateAction::ApplyChanges(StorageChanges::Import(_)))
}
}
/// Block import trait.
#[async_trait::async_trait]
pub trait BlockImport<B: BlockT> {
/// The error type.
type Error: std::error::Error + Send + 'static;
/// Check block preconditions.
async fn check_block(
&mut self,
block: BlockCheckParams<B>,
) -> Result<ImportResult, Self::Error>;
/// Import a block.
async fn import_block(
&mut self,
block: BlockImportParams<B>,
) -> Result<ImportResult, Self::Error>;
}
#[async_trait::async_trait]
impl<B: BlockT> BlockImport<B> for crate::import_queue::BoxBlockImport<B> {
type Error = sp_consensus::error::Error;
/// Check block preconditions.
async fn check_block(
&mut self,
block: BlockCheckParams<B>,
) -> Result<ImportResult, Self::Error> {
(**self).check_block(block).await
}
/// Import a block.
async fn import_block(
&mut self,
block: BlockImportParams<B>,
) -> Result<ImportResult, Self::Error> {
(**self).import_block(block).await
}
}
#[async_trait::async_trait]
impl<B: BlockT, T, E: std::error::Error + Send + 'static> BlockImport<B> for Arc<T>
where
for<'r> &'r T: BlockImport<B, Error = E>,
T: Send + Sync,
{
type Error = E;
async fn check_block(
&mut self,
block: BlockCheckParams<B>,
) -> Result<ImportResult, Self::Error> {
(&**self).check_block(block).await
}
async fn import_block(
&mut self,
block: BlockImportParams<B>,
) -> Result<ImportResult, Self::Error> {
(&**self).import_block(block).await
}
}
/// Justification import trait
#[async_trait::async_trait]
pub trait JustificationImport<B: BlockT> {
type Error: std::error::Error + Send + 'static;
/// Called by the import queue when it is started. Returns a list of justifications to request
/// from the network.
async fn on_start(&mut self) -> Vec<(B::Hash, NumberFor<B>)>;
/// Import a Block justification and finalize the given block.
async fn import_justification(
&mut self,
hash: B::Hash,
number: NumberFor<B>,
justification: Justification,
) -> Result<(), Self::Error>;
}
/// Control the synchronization process of block justifications.
///
/// When importing blocks different consensus engines might require that
/// additional finality data is provided (i.e. a justification for the block).
/// This trait abstracts the required methods to issue those requests
pub trait JustificationSyncLink<B: BlockT>: Send + Sync {
/// Request a justification for the given block.
fn request_justification(&self, hash: &B::Hash, number: NumberFor<B>);
/// Clear all pending justification requests.
fn clear_justification_requests(&self);
}
impl<B: BlockT> JustificationSyncLink<B> for () {
fn request_justification(&self, _hash: &B::Hash, _number: NumberFor<B>) {}
fn clear_justification_requests(&self) {}
}
impl<B: BlockT, L: JustificationSyncLink<B>> JustificationSyncLink<B> for Arc<L> {
fn request_justification(&self, hash: &B::Hash, number: NumberFor<B>) {
L::request_justification(self, hash, number);
}
fn clear_justification_requests(&self) {
L::clear_justification_requests(self);
}
}