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// Copyright 2021 Parity Technologies (UK) Ltd.
// This file is part of Cumulus.
// Cumulus 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 Cumulus. If not, see <http://www.gnu.org/licenses/>.
use crate::{ParachainInherentData, INHERENT_IDENTIFIER};
use codec::Decode;
use cumulus_primitives_core::{
relay_chain, InboundDownwardMessage, InboundHrmpMessage, ParaId, PersistedValidationData,
};
use sc_client_api::{Backend, StorageProvider};
use sp_core::twox_128;
use sp_inherents::{InherentData, InherentDataProvider};
use sp_runtime::traits::Block;
use std::collections::BTreeMap;
use cumulus_test_relay_sproof_builder::RelayStateSproofBuilder;
/// Inherent data provider that supplies mocked validation data.
///
/// This is useful when running a node that is not actually backed by any relay chain.
/// For example when running a local node, or running integration tests.
///
/// We mock a relay chain block number as follows:
/// relay_block_number = offset + relay_blocks_per_para_block * current_para_block
/// To simulate a parachain that starts in relay block 1000 and gets a block in every other relay
/// block, use 1000 and 2
///
/// Optionally, mock XCM messages can be injected into the runtime. When mocking XCM,
/// in addition to the messages themselves, you must provide some information about
/// your parachain's configuration in order to mock the MQC heads properly.
/// See [`MockXcmConfig`] for more information
pub struct MockValidationDataInherentDataProvider<R = ()> {
/// The current block number of the local block chain (the parachain)
pub current_para_block: u32,
/// The relay block in which this parachain appeared to start. This will be the relay block
/// number in para block #P1
pub relay_offset: u32,
/// The number of relay blocks that elapses between each parablock. Probably set this to 1 or 2
/// to simulate optimistic or realistic relay chain behavior.
pub relay_blocks_per_para_block: u32,
/// Number of parachain blocks per relay chain epoch
/// Mock epoch is computed by dividing `current_para_block` by this value.
pub para_blocks_per_relay_epoch: u32,
/// Function to mock BABE one epoch ago randomness
pub relay_randomness_config: R,
/// XCM messages and associated configuration information.
pub xcm_config: MockXcmConfig,
/// Inbound downward XCM messages to be injected into the block.
pub raw_downward_messages: Vec<Vec<u8>>,
// Inbound Horizontal messages sorted by channel
pub raw_horizontal_messages: Vec<(ParaId, Vec<u8>)>,
}
pub trait GenerateRandomness<I> {
fn generate_randomness(&self, input: I) -> relay_chain::Hash;
}
impl GenerateRandomness<u64> for () {
/// Default implementation uses relay epoch as randomness value
/// A more seemingly random implementation may hash the relay epoch instead
fn generate_randomness(&self, input: u64) -> relay_chain::Hash {
let mut mock_randomness: [u8; 32] = [0u8; 32];
mock_randomness[..8].copy_from_slice(&input.to_be_bytes());
mock_randomness.into()
}
}
/// Parameters for how the Mock inherent data provider should inject XCM messages.
/// In addition to the messages themselves, some information about the parachain's
/// configuration is also required so that the MQC heads can be read out of the
/// parachain's storage, and the corresponding relay data mocked.
#[derive(Default)]
pub struct MockXcmConfig {
/// The parachain id of the parachain being mocked.
pub para_id: ParaId,
/// The starting state of the dmq_mqc_head.
pub starting_dmq_mqc_head: relay_chain::Hash,
/// The starting state of each parachain's mqc head
pub starting_hrmp_mqc_heads: BTreeMap<ParaId, relay_chain::Hash>,
}
/// The name of the parachain system in the runtime.
///
/// This name is used by frame to prefix storage items and will be required to read data from the
/// storage.
///
/// The `Default` implementation sets the name to `ParachainSystem`.
pub struct ParachainSystemName(pub Vec<u8>);
impl Default for ParachainSystemName {
fn default() -> Self {
Self(b"ParachainSystem".to_vec())
}
}
impl MockXcmConfig {
/// Create a MockXcmConfig by reading the mqc_heads directly
/// from the storage of a previous block.
pub fn new<B: Block, BE: Backend<B>, C: StorageProvider<B, BE>>(
client: &C,
parent_block: B::Hash,
para_id: ParaId,
parachain_system_name: ParachainSystemName,
) -> Self {
let starting_dmq_mqc_head = client
.storage(
parent_block,
&sp_storage::StorageKey(
[twox_128(¶chain_system_name.0), twox_128(b"LastDmqMqcHead")]
.concat()
.to_vec(),
),
)
.expect("We should be able to read storage from the parent block.")
.map(|ref mut raw_data| {
Decode::decode(&mut &raw_data.0[..]).expect("Stored data should decode correctly")
})
.unwrap_or_default();
let starting_hrmp_mqc_heads = client
.storage(
parent_block,
&sp_storage::StorageKey(
[twox_128(¶chain_system_name.0), twox_128(b"LastHrmpMqcHeads")]
.concat()
.to_vec(),
),
)
.expect("We should be able to read storage from the parent block.")
.map(|ref mut raw_data| {
Decode::decode(&mut &raw_data.0[..]).expect("Stored data should decode correctly")
})
.unwrap_or_default();
Self { para_id, starting_dmq_mqc_head, starting_hrmp_mqc_heads }
}
}
#[async_trait::async_trait]
impl<R: Send + Sync + GenerateRandomness<u64>> InherentDataProvider
for MockValidationDataInherentDataProvider<R>
{
async fn provide_inherent_data(
&self,
inherent_data: &mut InherentData,
) -> Result<(), sp_inherents::Error> {
// Calculate the mocked relay block based on the current para block
let relay_parent_number =
self.relay_offset + self.relay_blocks_per_para_block * self.current_para_block;
// Use the "sproof" (spoof proof) builder to build valid mock state root and proof.
let mut sproof_builder =
RelayStateSproofBuilder { para_id: self.xcm_config.para_id, ..Default::default() };
// Process the downward messages and set up the correct head
let mut downward_messages = Vec::new();
let mut dmq_mqc = crate::MessageQueueChain(self.xcm_config.starting_dmq_mqc_head);
for msg in &self.raw_downward_messages {
let wrapped = InboundDownwardMessage { sent_at: relay_parent_number, msg: msg.clone() };
dmq_mqc.extend_downward(&wrapped);
downward_messages.push(wrapped);
}
sproof_builder.dmq_mqc_head = Some(dmq_mqc.head());
// Process the hrmp messages and set up the correct heads
// Begin by collecting them into a Map
let mut horizontal_messages = BTreeMap::<ParaId, Vec<InboundHrmpMessage>>::new();
for (para_id, msg) in &self.raw_horizontal_messages {
let wrapped = InboundHrmpMessage { sent_at: relay_parent_number, data: msg.clone() };
horizontal_messages.entry(*para_id).or_default().push(wrapped);
}
// Now iterate again, updating the heads as we go
for (para_id, messages) in &horizontal_messages {
let mut channel_mqc = crate::MessageQueueChain(
*self
.xcm_config
.starting_hrmp_mqc_heads
.get(para_id)
.unwrap_or(&relay_chain::Hash::default()),
);
for message in messages {
channel_mqc.extend_hrmp(message);
}
sproof_builder.upsert_inbound_channel(*para_id).mqc_head = Some(channel_mqc.head());
}
// Epoch is set equal to current para block / blocks per epoch
sproof_builder.current_epoch = if self.para_blocks_per_relay_epoch == 0 {
// do not divide by 0 => set epoch to para block number
self.current_para_block.into()
} else {
(self.current_para_block / self.para_blocks_per_relay_epoch).into()
};
// Randomness is set by randomness generator
sproof_builder.randomness =
self.relay_randomness_config.generate_randomness(self.current_para_block.into());
let (relay_parent_storage_root, proof) = sproof_builder.into_state_root_and_proof();
inherent_data.put_data(
INHERENT_IDENTIFIER,
&ParachainInherentData {
validation_data: PersistedValidationData {
parent_head: Default::default(),
relay_parent_storage_root,
relay_parent_number,
max_pov_size: Default::default(),
},
downward_messages,
horizontal_messages,
relay_chain_state: proof,
},
)
}
// Copied from the real implementation
async fn try_handle_error(
&self,
_: &sp_inherents::InherentIdentifier,
_: &[u8],
) -> Option<Result<(), sp_inherents::Error>> {
None
}
}