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// Copyright (C) Parity Technologies (UK) Ltd.
// This file is part of Polkadot.
// Polkadot 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.
// Polkadot 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 Polkadot. If not, see <http://www.gnu.org/licenses/>.
//! Primitive types which are strictly necessary from a parachain-execution point
//! of view.
use alloc::vec::Vec;
use bounded_collections::{BoundedVec, ConstU32};
use codec::{CompactAs, Decode, Encode, MaxEncodedLen};
use scale_info::TypeInfo;
use serde::{Deserialize, Serialize};
use sp_core::{bytes, RuntimeDebug, TypeId};
use sp_runtime::traits::Hash as _;
use sp_weights::Weight;
use polkadot_core_primitives::{Hash, OutboundHrmpMessage};
/// Block number type used by the relay chain.
pub use polkadot_core_primitives::BlockNumber as RelayChainBlockNumber;
/// Parachain head data included in the chain.
#[derive(
PartialEq,
Eq,
Clone,
PartialOrd,
Ord,
Encode,
Decode,
RuntimeDebug,
derive_more::From,
TypeInfo,
Serialize,
Deserialize,
)]
#[cfg_attr(feature = "std", derive(Hash, Default))]
pub struct HeadData(#[serde(with = "bytes")] pub Vec<u8>);
impl HeadData {
/// Returns the hash of this head data.
pub fn hash(&self) -> Hash {
sp_runtime::traits::BlakeTwo256::hash(&self.0)
}
}
/// Parachain validation code.
#[derive(
PartialEq,
Eq,
Clone,
Encode,
Decode,
RuntimeDebug,
derive_more::From,
TypeInfo,
Serialize,
Deserialize,
)]
#[cfg_attr(feature = "std", derive(Hash))]
pub struct ValidationCode(#[serde(with = "bytes")] pub Vec<u8>);
impl ValidationCode {
/// Get the blake2-256 hash of the validation code bytes.
pub fn hash(&self) -> ValidationCodeHash {
ValidationCodeHash(sp_runtime::traits::BlakeTwo256::hash(&self.0[..]))
}
}
/// Unit type wrapper around [`type@Hash`] that represents the blake2-256 hash
/// of validation code in particular.
///
/// This type is produced by [`ValidationCode::hash`].
///
/// This type makes it easy to enforce that a hash is a validation code hash on the type level.
#[derive(Clone, Copy, Encode, Decode, Hash, Eq, PartialEq, PartialOrd, Ord, TypeInfo)]
pub struct ValidationCodeHash(Hash);
impl core::fmt::Display for ValidationCodeHash {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
self.0.fmt(f)
}
}
impl core::fmt::Debug for ValidationCodeHash {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
write!(f, "{:?}", self.0)
}
}
impl AsRef<[u8]> for ValidationCodeHash {
fn as_ref(&self) -> &[u8] {
self.0.as_ref()
}
}
impl From<Hash> for ValidationCodeHash {
fn from(hash: Hash) -> ValidationCodeHash {
ValidationCodeHash(hash)
}
}
impl From<[u8; 32]> for ValidationCodeHash {
fn from(hash: [u8; 32]) -> ValidationCodeHash {
ValidationCodeHash(hash.into())
}
}
impl core::fmt::LowerHex for ValidationCodeHash {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
core::fmt::LowerHex::fmt(&self.0, f)
}
}
/// Parachain block data.
///
/// Contains everything required to validate para-block, may contain block and witness data.
#[derive(PartialEq, Eq, Clone, Encode, Decode, derive_more::From, TypeInfo, RuntimeDebug)]
#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
pub struct BlockData(#[cfg_attr(feature = "std", serde(with = "bytes"))] pub Vec<u8>);
/// Unique identifier of a parachain.
#[derive(
Clone,
CompactAs,
Copy,
Decode,
Default,
Encode,
Eq,
Hash,
MaxEncodedLen,
Ord,
PartialEq,
PartialOrd,
RuntimeDebug,
serde::Serialize,
serde::Deserialize,
TypeInfo,
)]
#[cfg_attr(feature = "std", derive(derive_more::Display))]
pub struct Id(u32);
impl TypeId for Id {
const TYPE_ID: [u8; 4] = *b"para";
}
impl From<Id> for u32 {
fn from(x: Id) -> Self {
x.0
}
}
impl From<u32> for Id {
fn from(x: u32) -> Self {
Id(x)
}
}
impl From<usize> for Id {
fn from(x: usize) -> Self {
// can't panic, so need to truncate
let x = x.try_into().unwrap_or(u32::MAX);
Id(x)
}
}
// When we added a second From impl for Id, type inference could no longer
// determine which impl should apply for things like `5.into()`. It therefore
// raised a bunch of errors in our test code, scattered throughout the
// various modules' tests, that there is no impl of `From<i32>` (`i32` being
// the default numeric type).
//
// We can't use `cfg(test)` here, because that configuration directive does not
// propagate between crates, which would fail to fix tests in crates other than
// this one.
//
// Instead, let's take advantage of the observation that what really matters for a
// ParaId within a test context is that it is unique and constant. I believe that
// there is no case where someone does `(-1).into()` anyway, but if they do, it
// never matters whether the actual contained ID is `-1` or `4294967295`. Nobody
// does arithmetic on a `ParaId`; doing so would be a bug.
impl From<i32> for Id {
fn from(x: i32) -> Self {
Id(x as u32)
}
}
// System parachain ID is considered `< 2000`.
const SYSTEM_INDEX_END: u32 = 1999;
const PUBLIC_INDEX_START: u32 = 2000;
/// The ID of the first publicly registrable parachain.
pub const LOWEST_PUBLIC_ID: Id = Id(PUBLIC_INDEX_START);
impl Id {
/// Create an `Id`.
pub const fn new(id: u32) -> Self {
Self(id)
}
}
/// Determine if a parachain is a system parachain or not.
pub trait IsSystem {
/// Returns `true` if a parachain is a system parachain, `false` otherwise.
fn is_system(&self) -> bool;
}
impl IsSystem for Id {
fn is_system(&self) -> bool {
self.0 <= SYSTEM_INDEX_END
}
}
impl core::ops::Add<u32> for Id {
type Output = Self;
fn add(self, other: u32) -> Self {
Self(self.0 + other)
}
}
impl core::ops::Sub<u32> for Id {
type Output = Self;
fn sub(self, other: u32) -> Self {
Self(self.0 - other)
}
}
#[derive(
Clone, Copy, Default, Encode, Decode, Eq, PartialEq, Ord, PartialOrd, RuntimeDebug, TypeInfo,
)]
pub struct Sibling(pub Id);
impl From<Id> for Sibling {
fn from(i: Id) -> Self {
Self(i)
}
}
impl From<Sibling> for Id {
fn from(i: Sibling) -> Self {
i.0
}
}
impl AsRef<Id> for Sibling {
fn as_ref(&self) -> &Id {
&self.0
}
}
impl TypeId for Sibling {
const TYPE_ID: [u8; 4] = *b"sibl";
}
impl From<Sibling> for u32 {
fn from(x: Sibling) -> Self {
x.0.into()
}
}
impl From<u32> for Sibling {
fn from(x: u32) -> Self {
Sibling(x.into())
}
}
impl IsSystem for Sibling {
fn is_system(&self) -> bool {
IsSystem::is_system(&self.0)
}
}
/// A type that uniquely identifies an HRMP channel. An HRMP channel is established between two
/// paras. In text, we use the notation `(A, B)` to specify a channel between A and B. The channels
/// are unidirectional, meaning that `(A, B)` and `(B, A)` refer to different channels. The
/// convention is that we use the first item tuple for the sender and the second for the recipient.
/// Only one channel is allowed between two participants in one direction, i.e. there cannot be 2
/// different channels identified by `(A, B)`. A channel with the same para id in sender and
/// recipient is invalid. That is, however, not enforced.
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Encode, Decode, RuntimeDebug, TypeInfo)]
#[cfg_attr(feature = "std", derive(Hash))]
pub struct HrmpChannelId {
/// The para that acts as the sender in this channel.
pub sender: Id,
/// The para that acts as the recipient in this channel.
pub recipient: Id,
}
impl HrmpChannelId {
/// Returns true if the given id corresponds to either the sender or the recipient.
pub fn is_participant(&self, id: Id) -> bool {
id == self.sender || id == self.recipient
}
}
/// A message from a parachain to its Relay Chain.
pub type UpwardMessage = Vec<u8>;
/// Something that should be called when a downward message is received.
pub trait DmpMessageHandler {
/// Handle some incoming DMP messages (note these are individual XCM messages).
///
/// Also, process messages up to some `max_weight`.
fn handle_dmp_messages(
iter: impl Iterator<Item = (RelayChainBlockNumber, Vec<u8>)>,
max_weight: Weight,
) -> Weight;
}
impl DmpMessageHandler for () {
fn handle_dmp_messages(
iter: impl Iterator<Item = (RelayChainBlockNumber, Vec<u8>)>,
_max_weight: Weight,
) -> Weight {
iter.for_each(drop);
Weight::zero()
}
}
/// The aggregate XCMP message format.
#[derive(
Copy,
Clone,
Eq,
PartialEq,
Ord,
PartialOrd,
Encode,
Decode,
TypeInfo,
RuntimeDebug,
MaxEncodedLen,
)]
pub enum XcmpMessageFormat {
/// Encoded `VersionedXcm` messages, all concatenated.
ConcatenatedVersionedXcm,
/// Encoded `Vec<u8>` messages, all concatenated.
ConcatenatedEncodedBlob,
/// One or more channel control signals; these should be interpreted immediately upon receipt
/// from the relay-chain.
Signals,
}
/// Something that should be called for each batch of messages received over XCMP.
pub trait XcmpMessageHandler {
/// Handle some incoming XCMP messages (note these are the big one-per-block aggregate
/// messages).
///
/// Also, process messages up to some `max_weight`.
fn handle_xcmp_messages<'a, I: Iterator<Item = (Id, RelayChainBlockNumber, &'a [u8])>>(
iter: I,
max_weight: Weight,
) -> Weight;
}
impl XcmpMessageHandler for () {
fn handle_xcmp_messages<'a, I: Iterator<Item = (Id, RelayChainBlockNumber, &'a [u8])>>(
iter: I,
_max_weight: Weight,
) -> Weight {
for _ in iter {}
Weight::zero()
}
}
/// Validation parameters for evaluating the parachain validity function.
// TODO: balance downloads (https://github.com/paritytech/polkadot/issues/220)
#[derive(PartialEq, Eq, Decode, Clone)]
#[cfg_attr(feature = "std", derive(Debug, Encode))]
pub struct ValidationParams {
/// Previous head-data.
pub parent_head: HeadData,
/// The collation body.
pub block_data: BlockData,
/// The current relay-chain block number.
pub relay_parent_number: RelayChainBlockNumber,
/// The relay-chain block's storage root.
pub relay_parent_storage_root: Hash,
}
/// Maximum number of HRMP messages allowed per candidate.
///
/// We also use this as a generous limit, which still prevents possible memory exhaustion, from
/// malicious parachains that may otherwise return a huge amount of messages in `ValidationResult`.
pub const MAX_HORIZONTAL_MESSAGE_NUM: u32 = 16 * 1024;
/// Maximum number of UMP messages allowed per candidate.
///
/// We also use this as a generous limit, which still prevents possible memory exhaustion, from
/// malicious parachains that may otherwise return a huge amount of messages in `ValidationResult`.
pub const MAX_UPWARD_MESSAGE_NUM: u32 = 16 * 1024;
pub type UpwardMessages = BoundedVec<UpwardMessage, ConstU32<MAX_UPWARD_MESSAGE_NUM>>;
pub type HorizontalMessages =
BoundedVec<OutboundHrmpMessage<Id>, ConstU32<MAX_HORIZONTAL_MESSAGE_NUM>>;
/// The result of parachain validation.
// TODO: balance uploads (https://github.com/paritytech/polkadot/issues/220)
#[derive(PartialEq, Eq, Clone, Encode)]
#[cfg_attr(feature = "std", derive(Debug, Decode))]
pub struct ValidationResult {
/// New head data that should be included in the relay chain state.
pub head_data: HeadData,
/// An update to the validation code that should be scheduled in the relay chain.
pub new_validation_code: Option<ValidationCode>,
/// Upward messages send by the Parachain.
pub upward_messages: UpwardMessages,
/// Outbound horizontal messages sent by the parachain.
pub horizontal_messages: HorizontalMessages,
/// Number of downward messages that were processed by the Parachain.
///
/// It is expected that the Parachain processes them from first to last.
pub processed_downward_messages: u32,
/// The mark which specifies the block number up to which all inbound HRMP messages are
/// processed.
pub hrmp_watermark: RelayChainBlockNumber,
}