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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 crate::{
defensive,
storage::transactional::with_transaction_opaque_err,
traits::{
Defensive, GetStorageVersion, NoStorageVersionSet, PalletInfoAccess, SafeMode,
StorageVersion,
},
weights::{RuntimeDbWeight, Weight, WeightMeter},
};
use codec::{Decode, Encode, MaxEncodedLen};
use impl_trait_for_tuples::impl_for_tuples;
use sp_arithmetic::traits::Bounded;
use sp_core::Get;
use sp_io::{hashing::twox_128, storage::clear_prefix, KillStorageResult};
use sp_runtime::traits::Zero;
use sp_std::{marker::PhantomData, vec::Vec};
/// Handles storage migration pallet versioning.
///
/// [`VersionedMigration`] allows developers to write migrations without worrying about checking and
/// setting storage versions. Instead, the developer wraps their migration in this struct which
/// takes care of version handling using best practices.
///
/// It takes 5 type parameters:
/// - `From`: The version being upgraded from.
/// - `To`: The version being upgraded to.
/// - `Inner`: An implementation of `UncheckedOnRuntimeUpgrade`.
/// - `Pallet`: The Pallet being upgraded.
/// - `Weight`: The runtime's RuntimeDbWeight implementation.
///
/// When a [`VersionedMigration`] `on_runtime_upgrade`, `pre_upgrade`, or `post_upgrade` method is
/// called, the on-chain version of the pallet is compared to `From`. If they match, the `Inner`
/// `UncheckedOnRuntimeUpgrade` is called and the pallets on-chain version is set to `To`
/// after the migration. Otherwise, a warning is logged notifying the developer that the upgrade was
/// a noop and should probably be removed.
///
/// By not bounding `Inner` with `OnRuntimeUpgrade`, we prevent developers from
/// accidentally using the unchecked version of the migration in a runtime upgrade instead of
/// [`VersionedMigration`].
///
/// ### Examples
/// ```ignore
/// // In file defining migrations
///
/// /// Private module containing *version unchecked* migration logic.
/// ///
/// /// Should only be used by the [`VersionedMigration`] type in this module to create something to
/// /// export.
/// ///
/// /// We keep this private so the unversioned migration cannot accidentally be used in any runtimes.
/// ///
/// /// For more about this pattern of keeping items private, see
/// /// - https://github.com/rust-lang/rust/issues/30905
/// /// - https://internals.rust-lang.org/t/lang-team-minutes-private-in-public-rules/4504/40
/// mod version_unchecked {
/// use super::*;
/// pub struct VersionUncheckedMigrateV5ToV6<T>(sp_std::marker::PhantomData<T>);
/// impl<T: Config> UncheckedOnRuntimeUpgrade for VersionUncheckedMigrateV5ToV6<T> {
/// // `UncheckedOnRuntimeUpgrade` implementation...
/// }
/// }
///
/// pub type MigrateV5ToV6<T, I> =
/// VersionedMigration<
/// 5,
/// 6,
/// VersionUncheckedMigrateV5ToV6<T, I>,
/// crate::pallet::Pallet<T, I>,
/// <T as frame_system::Config>::DbWeight
/// >;
///
/// // Migrations tuple to pass to the Executive pallet:
/// pub type Migrations = (
/// // other migrations...
/// MigrateV5ToV6<T, ()>,
/// // other migrations...
/// );
/// ```
pub struct VersionedMigration<const FROM: u16, const TO: u16, Inner, Pallet, Weight> {
_marker: PhantomData<(Inner, Pallet, Weight)>,
}
/// A helper enum to wrap the pre_upgrade bytes like an Option before passing them to post_upgrade.
/// This enum is used rather than an Option to make the API clearer to the developer.
#[derive(Encode, Decode)]
pub enum VersionedPostUpgradeData {
/// The migration ran, inner vec contains pre_upgrade data.
MigrationExecuted(sp_std::vec::Vec<u8>),
/// This migration is a noop, do not run post_upgrade checks.
Noop,
}
/// Implementation of the `OnRuntimeUpgrade` trait for `VersionedMigration`.
///
/// Its main function is to perform the runtime upgrade in `on_runtime_upgrade` only if the on-chain
/// version of the pallets storage matches `From`, and after the upgrade set the on-chain storage to
/// `To`. If the versions do not match, it writes a log notifying the developer that the migration
/// is a noop.
impl<
const FROM: u16,
const TO: u16,
Inner: crate::traits::UncheckedOnRuntimeUpgrade,
Pallet: GetStorageVersion<InCodeStorageVersion = StorageVersion> + PalletInfoAccess,
DbWeight: Get<RuntimeDbWeight>,
> crate::traits::OnRuntimeUpgrade for VersionedMigration<FROM, TO, Inner, Pallet, DbWeight>
{
/// Executes pre_upgrade if the migration will run, and wraps the pre_upgrade bytes in
/// [`VersionedPostUpgradeData`] before passing them to post_upgrade, so it knows whether the
/// migration ran or not.
#[cfg(feature = "try-runtime")]
fn pre_upgrade() -> Result<sp_std::vec::Vec<u8>, sp_runtime::TryRuntimeError> {
let on_chain_version = Pallet::on_chain_storage_version();
if on_chain_version == FROM {
Ok(VersionedPostUpgradeData::MigrationExecuted(Inner::pre_upgrade()?).encode())
} else {
Ok(VersionedPostUpgradeData::Noop.encode())
}
}
/// Executes the versioned runtime upgrade.
///
/// First checks if the pallets on-chain storage version matches the version of this upgrade. If
/// it matches, it calls `Inner::on_runtime_upgrade`, updates the on-chain version, and returns
/// the weight. If it does not match, it writes a log notifying the developer that the migration
/// is a noop.
fn on_runtime_upgrade() -> Weight {
let on_chain_version = Pallet::on_chain_storage_version();
if on_chain_version == FROM {
log::info!(
"🚚 Pallet {:?} VersionedMigration migrating storage version from {:?} to {:?}.",
Pallet::name(),
FROM,
TO
);
// Execute the migration
let weight = Inner::on_runtime_upgrade();
// Update the on-chain version
StorageVersion::new(TO).put::<Pallet>();
weight.saturating_add(DbWeight::get().reads_writes(1, 1))
} else {
log::warn!(
"🚚 Pallet {:?} VersionedMigration migration {}->{} can be removed; on-chain is already at {:?}.",
Pallet::name(),
FROM,
TO,
on_chain_version
);
DbWeight::get().reads(1)
}
}
/// Executes `Inner::post_upgrade` if the migration just ran.
///
/// pre_upgrade passes [`VersionedPostUpgradeData::MigrationExecuted`] to post_upgrade if
/// the migration ran, and [`VersionedPostUpgradeData::Noop`] otherwise.
#[cfg(feature = "try-runtime")]
fn post_upgrade(
versioned_post_upgrade_data_bytes: sp_std::vec::Vec<u8>,
) -> Result<(), sp_runtime::TryRuntimeError> {
use codec::DecodeAll;
match <VersionedPostUpgradeData>::decode_all(&mut &versioned_post_upgrade_data_bytes[..])
.map_err(|_| "VersionedMigration post_upgrade failed to decode PreUpgradeData")?
{
VersionedPostUpgradeData::MigrationExecuted(inner_bytes) =>
Inner::post_upgrade(inner_bytes),
VersionedPostUpgradeData::Noop => Ok(()),
}
}
}
/// Can store the in-code pallet version on-chain.
pub trait StoreInCodeStorageVersion<T: GetStorageVersion + PalletInfoAccess> {
/// Write the in-code storage version on-chain.
fn store_in_code_storage_version();
}
impl<T: GetStorageVersion<InCodeStorageVersion = StorageVersion> + PalletInfoAccess>
StoreInCodeStorageVersion<T> for StorageVersion
{
fn store_in_code_storage_version() {
let version = <T as GetStorageVersion>::in_code_storage_version();
version.put::<T>();
}
}
impl<T: GetStorageVersion<InCodeStorageVersion = NoStorageVersionSet> + PalletInfoAccess>
StoreInCodeStorageVersion<T> for NoStorageVersionSet
{
fn store_in_code_storage_version() {
StorageVersion::default().put::<T>();
}
}
/// Trait used by [`migrate_from_pallet_version_to_storage_version`] to do the actual migration.
pub trait PalletVersionToStorageVersionHelper {
fn migrate(db_weight: &RuntimeDbWeight) -> Weight;
}
impl<T: GetStorageVersion + PalletInfoAccess> PalletVersionToStorageVersionHelper for T
where
T::InCodeStorageVersion: StoreInCodeStorageVersion<T>,
{
fn migrate(db_weight: &RuntimeDbWeight) -> Weight {
const PALLET_VERSION_STORAGE_KEY_POSTFIX: &[u8] = b":__PALLET_VERSION__:";
fn pallet_version_key(name: &str) -> [u8; 32] {
crate::storage::storage_prefix(name.as_bytes(), PALLET_VERSION_STORAGE_KEY_POSTFIX)
}
sp_io::storage::clear(&pallet_version_key(<T as PalletInfoAccess>::name()));
<T::InCodeStorageVersion as StoreInCodeStorageVersion<T>>::store_in_code_storage_version();
db_weight.writes(2)
}
}
#[cfg_attr(all(not(feature = "tuples-96"), not(feature = "tuples-128")), impl_for_tuples(64))]
#[cfg_attr(all(feature = "tuples-96", not(feature = "tuples-128")), impl_for_tuples(96))]
#[cfg_attr(feature = "tuples-128", impl_for_tuples(128))]
impl PalletVersionToStorageVersionHelper for T {
fn migrate(db_weight: &RuntimeDbWeight) -> Weight {
let mut weight = Weight::zero();
for_tuples!( #( weight = weight.saturating_add(T::migrate(db_weight)); )* );
weight
}
}
/// Migrate from the `PalletVersion` struct to the new [`StorageVersion`] struct.
///
/// This will remove all `PalletVersion's` from the state and insert the in-code storage version.
pub fn migrate_from_pallet_version_to_storage_version<
Pallets: PalletVersionToStorageVersionHelper,
>(
db_weight: &RuntimeDbWeight,
) -> Weight {
Pallets::migrate(db_weight)
}
/// `RemovePallet` is a utility struct used to remove all storage items associated with a specific
/// pallet.
///
/// This struct is generic over two parameters:
/// - `P` is a type that implements the `Get` trait for a static string, representing the pallet's
/// name.
/// - `DbWeight` is a type that implements the `Get` trait for `RuntimeDbWeight`, providing the
/// weight for database operations.
///
/// On runtime upgrade, the `on_runtime_upgrade` function will clear all storage items associated
/// with the specified pallet, logging the number of keys removed. If the `try-runtime` feature is
/// enabled, the `pre_upgrade` and `post_upgrade` functions can be used to verify the storage
/// removal before and after the upgrade.
///
/// # Examples:
/// ```ignore
/// construct_runtime! {
/// pub enum Runtime
/// {
/// System: frame_system = 0,
///
/// SomePalletToRemove: pallet_something = 1,
/// AnotherPalletToRemove: pallet_something_else = 2,
///
/// YourOtherPallets...
/// }
/// };
///
/// parameter_types! {
/// pub const SomePalletToRemoveStr: &'static str = "SomePalletToRemove";
/// pub const AnotherPalletToRemoveStr: &'static str = "AnotherPalletToRemove";
/// }
///
/// pub type Migrations = (
/// RemovePallet<SomePalletToRemoveStr, RocksDbWeight>,
/// RemovePallet<AnotherPalletToRemoveStr, RocksDbWeight>,
/// AnyOtherMigrations...
/// );
///
/// pub type Executive = frame_executive::Executive<
/// Runtime,
/// Block,
/// frame_system::ChainContext<Runtime>,
/// Runtime,
/// Migrations
/// >;
/// ```
///
/// WARNING: `RemovePallet` has no guard rails preventing it from bricking the chain if the
/// operation of removing storage for the given pallet would exceed the block weight limit.
///
/// If your pallet has too many keys to be removed in a single block, it is advised to wait for
/// a multi-block scheduler currently under development which will allow for removal of storage
/// items (and performing other heavy migrations) over multiple blocks
/// (see <https://github.com/paritytech/substrate/issues/13690>).
pub struct RemovePallet<P: Get<&'static str>, DbWeight: Get<RuntimeDbWeight>>(
PhantomData<(P, DbWeight)>,
);
impl<P: Get<&'static str>, DbWeight: Get<RuntimeDbWeight>> frame_support::traits::OnRuntimeUpgrade
for RemovePallet<P, DbWeight>
{
fn on_runtime_upgrade() -> frame_support::weights::Weight {
let hashed_prefix = twox_128(P::get().as_bytes());
let keys_removed = match clear_prefix(&hashed_prefix, None) {
KillStorageResult::AllRemoved(value) => value,
KillStorageResult::SomeRemaining(value) => {
log::error!(
"`clear_prefix` failed to remove all keys for {}. THIS SHOULD NEVER HAPPEN! 🚨",
P::get()
);
value
},
} as u64;
log::info!("Removed {} {} keys 🧹", keys_removed, P::get());
DbWeight::get().reads_writes(keys_removed + 1, keys_removed)
}
#[cfg(feature = "try-runtime")]
fn pre_upgrade() -> Result<sp_std::vec::Vec<u8>, sp_runtime::TryRuntimeError> {
use crate::storage::unhashed::contains_prefixed_key;
let hashed_prefix = twox_128(P::get().as_bytes());
match contains_prefixed_key(&hashed_prefix) {
true => log::info!("Found {} keys pre-removal 👀", P::get()),
false => log::warn!(
"Migration RemovePallet<{}> can be removed (no keys found pre-removal).",
P::get()
),
};
Ok(sp_std::vec::Vec::new())
}
#[cfg(feature = "try-runtime")]
fn post_upgrade(_state: sp_std::vec::Vec<u8>) -> Result<(), sp_runtime::TryRuntimeError> {
use crate::storage::unhashed::contains_prefixed_key;
let hashed_prefix = twox_128(P::get().as_bytes());
match contains_prefixed_key(&hashed_prefix) {
true => {
log::error!("{} has keys remaining post-removal ❗", P::get());
return Err("Keys remaining post-removal, this should never happen 🚨".into())
},
false => log::info!("No {} keys found post-removal 🎉", P::get()),
};
Ok(())
}
}
/// A migration that can proceed in multiple steps.
pub trait SteppedMigration {
/// The cursor type that stores the progress (aka. state) of this migration.
type Cursor: codec::FullCodec + codec::MaxEncodedLen;
/// The unique identifier type of this migration.
type Identifier: codec::FullCodec + codec::MaxEncodedLen;
/// The unique identifier of this migration.
///
/// If two migrations have the same identifier, then they are assumed to be identical.
fn id() -> Self::Identifier;
/// The maximum number of steps that this migration can take.
///
/// This can be used to enforce progress and prevent migrations becoming stuck forever. A
/// migration that exceeds its max steps is treated as failed. `None` means that there is no
/// limit.
fn max_steps() -> Option<u32> {
None
}
/// Try to migrate as much as possible with the given weight.
///
/// **ANY STORAGE CHANGES MUST BE ROLLED-BACK BY THE CALLER UPON ERROR.** This is necessary
/// since the caller cannot return a cursor in the error case. [`Self::transactional_step`] is
/// provided as convenience for a caller. A cursor of `None` implies that the migration is at
/// its end. A migration that once returned `Nonce` is guaranteed to never be called again.
fn step(
cursor: Option<Self::Cursor>,
meter: &mut WeightMeter,
) -> Result<Option<Self::Cursor>, SteppedMigrationError>;
/// Same as [`Self::step`], but rolls back pending changes in the error case.
fn transactional_step(
mut cursor: Option<Self::Cursor>,
meter: &mut WeightMeter,
) -> Result<Option<Self::Cursor>, SteppedMigrationError> {
with_transaction_opaque_err(move || match Self::step(cursor, meter) {
Ok(new_cursor) => {
cursor = new_cursor;
sp_runtime::TransactionOutcome::Commit(Ok(cursor))
},
Err(err) => sp_runtime::TransactionOutcome::Rollback(Err(err)),
})
.map_err(|()| SteppedMigrationError::Failed)?
}
}
/// Error that can occur during a [`SteppedMigration`].
#[derive(Debug, Encode, Decode, MaxEncodedLen, scale_info::TypeInfo)]
pub enum SteppedMigrationError {
// Transient errors:
/// The remaining weight is not enough to do anything.
///
/// Can be resolved by calling with at least `required` weight. Note that calling it with
/// exactly `required` weight could cause it to not make any progress.
InsufficientWeight {
/// Amount of weight required to make progress.
required: Weight,
},
// Permanent errors:
/// The migration cannot decode its cursor and therefore not proceed.
///
/// This should not happen unless (1) the migration itself returned an invalid cursor in a
/// previous iteration, (2) the storage got corrupted or (3) there is a bug in the caller's
/// code.
InvalidCursor,
/// The migration encountered a permanent error and cannot continue.
Failed,
}
/// A generic migration identifier that can be used by MBMs.
///
/// It is not required that migrations use this identifier type, but it can help.
#[derive(MaxEncodedLen, Encode, Decode)]
pub struct MigrationId<const N: usize> {
pub pallet_id: [u8; N],
pub version_from: u8,
pub version_to: u8,
}
/// Notification handler for status updates regarding Multi-Block-Migrations.
#[impl_trait_for_tuples::impl_for_tuples(8)]
pub trait MigrationStatusHandler {
/// Notifies of the start of a runtime migration.
fn started() {}
/// Notifies of the completion of a runtime migration.
fn completed() {}
}
/// Handles a failed runtime migration.
///
/// This should never happen, but is here for completeness.
pub trait FailedMigrationHandler {
/// Infallibly handle a failed runtime migration.
///
/// Gets passed in the optional index of the migration in the batch that caused the failure.
/// Returning `None` means that no automatic handling should take place and the callee decides
/// in the implementation what to do.
fn failed(migration: Option<u32>) -> FailedMigrationHandling;
}
/// Do now allow any transactions to be processed after a runtime upgrade failed.
///
/// This is **not a sane default**, since it prevents governance intervention.
pub struct FreezeChainOnFailedMigration;
impl FailedMigrationHandler for FreezeChainOnFailedMigration {
fn failed(_migration: Option<u32>) -> FailedMigrationHandling {
FailedMigrationHandling::KeepStuck
}
}
/// Enter safe mode on a failed runtime upgrade.
///
/// This can be very useful to manually intervene and fix the chain state. `Else` is used in case
/// that the safe mode could not be entered.
pub struct EnterSafeModeOnFailedMigration<SM, Else: FailedMigrationHandler>(
PhantomData<(SM, Else)>,
);
impl<Else: FailedMigrationHandler, SM: SafeMode> FailedMigrationHandler
for EnterSafeModeOnFailedMigration<SM, Else>
where
<SM as SafeMode>::BlockNumber: Bounded,
{
fn failed(migration: Option<u32>) -> FailedMigrationHandling {
let entered = if SM::is_entered() {
SM::extend(Bounded::max_value())
} else {
SM::enter(Bounded::max_value())
};
// If we could not enter or extend safe mode (for whatever reason), then we try the next.
if entered.is_err() {
Else::failed(migration)
} else {
FailedMigrationHandling::KeepStuck
}
}
}
/// How to proceed after a runtime upgrade failed.
///
/// There is NO SANE DEFAULT HERE. All options are very dangerous and should be used with care.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum FailedMigrationHandling {
/// Resume extrinsic processing of the chain. This will not resume the upgrade.
///
/// This should be supplemented with additional measures to ensure that the broken chain state
/// does not get further messed up by user extrinsics.
ForceUnstuck,
/// Set the cursor to `Stuck` and keep blocking extrinsics.
KeepStuck,
/// Don't do anything with the cursor and let the handler decide.
///
/// This can be useful in cases where the other two options would overwrite any changes that
/// were done by the handler to the cursor.
Ignore,
}
/// Something that can do multi step migrations.
pub trait MultiStepMigrator {
/// Hint for whether [`Self::step`] should be called.
fn ongoing() -> bool;
/// Do the next step in the MBM process.
///
/// Must gracefully handle the case that it is currently not upgrading.
fn step() -> Weight;
}
impl MultiStepMigrator for () {
fn ongoing() -> bool {
false
}
fn step() -> Weight {
Weight::zero()
}
}
/// Multiple [`SteppedMigration`].
pub trait SteppedMigrations {
/// The number of migrations that `Self` aggregates.
fn len() -> u32;
/// The `n`th [`SteppedMigration::id`].
///
/// Is guaranteed to return `Some` if `n < Self::len()`.
fn nth_id(n: u32) -> Option<Vec<u8>>;
/// The [`SteppedMigration::max_steps`] of the `n`th migration.
///
/// Is guaranteed to return `Some` if `n < Self::len()`.
fn nth_max_steps(n: u32) -> Option<Option<u32>>;
/// Do a [`SteppedMigration::step`] on the `n`th migration.
///
/// Is guaranteed to return `Some` if `n < Self::len()`.
fn nth_step(
n: u32,
cursor: Option<Vec<u8>>,
meter: &mut WeightMeter,
) -> Option<Result<Option<Vec<u8>>, SteppedMigrationError>>;
/// Do a [`SteppedMigration::transactional_step`] on the `n`th migration.
///
/// Is guaranteed to return `Some` if `n < Self::len()`.
fn nth_transactional_step(
n: u32,
cursor: Option<Vec<u8>>,
meter: &mut WeightMeter,
) -> Option<Result<Option<Vec<u8>>, SteppedMigrationError>>;
/// The maximal encoded length across all cursors.
fn cursor_max_encoded_len() -> usize;
/// The maximal encoded length across all identifiers.
fn identifier_max_encoded_len() -> usize;
/// Assert the integrity of the migrations.
///
/// Should be executed as part of a test prior to runtime usage. May or may not need
/// externalities.
#[cfg(feature = "std")]
fn integrity_test() -> Result<(), &'static str> {
use crate::ensure;
let l = Self::len();
for n in 0..l {
ensure!(Self::nth_id(n).is_some(), "id is None");
ensure!(Self::nth_max_steps(n).is_some(), "steps is None");
// The cursor that we use does not matter. Hence use empty.
ensure!(
Self::nth_step(n, Some(vec![]), &mut WeightMeter::new()).is_some(),
"steps is None"
);
ensure!(
Self::nth_transactional_step(n, Some(vec![]), &mut WeightMeter::new()).is_some(),
"steps is None"
);
}
Ok(())
}
}
impl SteppedMigrations for () {
fn len() -> u32 {
0
}
fn nth_id(_n: u32) -> Option<Vec<u8>> {
None
}
fn nth_max_steps(_n: u32) -> Option<Option<u32>> {
None
}
fn nth_step(
_n: u32,
_cursor: Option<Vec<u8>>,
_meter: &mut WeightMeter,
) -> Option<Result<Option<Vec<u8>>, SteppedMigrationError>> {
None
}
fn nth_transactional_step(
_n: u32,
_cursor: Option<Vec<u8>>,
_meter: &mut WeightMeter,
) -> Option<Result<Option<Vec<u8>>, SteppedMigrationError>> {
None
}
fn cursor_max_encoded_len() -> usize {
0
}
fn identifier_max_encoded_len() -> usize {
0
}
}
// A collection consisting of only a single migration.
impl<T: SteppedMigration> SteppedMigrations for T {
fn len() -> u32 {
1
}
fn nth_id(_n: u32) -> Option<Vec<u8>> {
Some(T::id().encode())
}
fn nth_max_steps(n: u32) -> Option<Option<u32>> {
// It should be generally fine to call with n>0, but the code should not attempt to.
n.is_zero()
.then_some(T::max_steps())
.defensive_proof("nth_max_steps should only be called with n==0")
}
fn nth_step(
_n: u32,
cursor: Option<Vec<u8>>,
meter: &mut WeightMeter,
) -> Option<Result<Option<Vec<u8>>, SteppedMigrationError>> {
if !_n.is_zero() {
defensive!("nth_step should only be called with n==0");
return None
}
let cursor = match cursor {
Some(cursor) => match T::Cursor::decode(&mut &cursor[..]) {
Ok(cursor) => Some(cursor),
Err(_) => return Some(Err(SteppedMigrationError::InvalidCursor)),
},
None => None,
};
Some(T::step(cursor, meter).map(|cursor| cursor.map(|cursor| cursor.encode())))
}
fn nth_transactional_step(
n: u32,
cursor: Option<Vec<u8>>,
meter: &mut WeightMeter,
) -> Option<Result<Option<Vec<u8>>, SteppedMigrationError>> {
if n != 0 {
defensive!("nth_transactional_step should only be called with n==0");
return None
}
let cursor = match cursor {
Some(cursor) => match T::Cursor::decode(&mut &cursor[..]) {
Ok(cursor) => Some(cursor),
Err(_) => return Some(Err(SteppedMigrationError::InvalidCursor)),
},
None => None,
};
Some(
T::transactional_step(cursor, meter).map(|cursor| cursor.map(|cursor| cursor.encode())),
)
}
fn cursor_max_encoded_len() -> usize {
T::Cursor::max_encoded_len()
}
fn identifier_max_encoded_len() -> usize {
T::Identifier::max_encoded_len()
}
}
#[impl_trait_for_tuples::impl_for_tuples(1, 30)]
impl SteppedMigrations for Tuple {
fn len() -> u32 {
for_tuples!( #( Tuple::len() )+* )
}
fn nth_id(n: u32) -> Option<Vec<u8>> {
let mut i = 0;
for_tuples!( #(
if (i + Tuple::len()) > n {
return Tuple::nth_id(n - i)
}
i += Tuple::len();
)* );
None
}
fn nth_step(
n: u32,
cursor: Option<Vec<u8>>,
meter: &mut WeightMeter,
) -> Option<Result<Option<Vec<u8>>, SteppedMigrationError>> {
let mut i = 0;
for_tuples!( #(
if (i + Tuple::len()) > n {
return Tuple::nth_step(n - i, cursor, meter)
}
i += Tuple::len();
)* );
None
}
fn nth_transactional_step(
n: u32,
cursor: Option<Vec<u8>>,
meter: &mut WeightMeter,
) -> Option<Result<Option<Vec<u8>>, SteppedMigrationError>> {
let mut i = 0;
for_tuples! ( #(
if (i + Tuple::len()) > n {
return Tuple::nth_transactional_step(n - i, cursor, meter)
}
i += Tuple::len();
)* );
None
}
fn nth_max_steps(n: u32) -> Option<Option<u32>> {
let mut i = 0;
for_tuples!( #(
if (i + Tuple::len()) > n {
return Tuple::nth_max_steps(n - i)
}
i += Tuple::len();
)* );
None
}
fn cursor_max_encoded_len() -> usize {
let mut max_len = 0;
for_tuples!( #(
max_len = max_len.max(Tuple::cursor_max_encoded_len());
)* );
max_len
}
fn identifier_max_encoded_len() -> usize {
let mut max_len = 0;
for_tuples!( #(
max_len = max_len.max(Tuple::identifier_max_encoded_len());
)* );
max_len
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{assert_ok, storage::unhashed};
#[derive(Decode, Encode, MaxEncodedLen, Eq, PartialEq)]
pub enum Either<L, R> {
Left(L),
Right(R),
}
pub struct M0;
impl SteppedMigration for M0 {
type Cursor = ();
type Identifier = u8;
fn id() -> Self::Identifier {
0
}
fn step(
_cursor: Option<Self::Cursor>,
_meter: &mut WeightMeter,
) -> Result<Option<Self::Cursor>, SteppedMigrationError> {
log::info!("M0");
unhashed::put(&[0], &());
Ok(None)
}
}
pub struct M1;
impl SteppedMigration for M1 {
type Cursor = ();
type Identifier = u8;
fn id() -> Self::Identifier {
1
}
fn step(
_cursor: Option<Self::Cursor>,
_meter: &mut WeightMeter,
) -> Result<Option<Self::Cursor>, SteppedMigrationError> {
log::info!("M1");
unhashed::put(&[1], &());
Ok(None)
}
fn max_steps() -> Option<u32> {
Some(1)
}
}
pub struct M2;
impl SteppedMigration for M2 {
type Cursor = ();
type Identifier = u8;
fn id() -> Self::Identifier {
2
}
fn step(
_cursor: Option<Self::Cursor>,
_meter: &mut WeightMeter,
) -> Result<Option<Self::Cursor>, SteppedMigrationError> {
log::info!("M2");
unhashed::put(&[2], &());
Ok(None)
}
fn max_steps() -> Option<u32> {
Some(2)
}
}
pub struct F0;
impl SteppedMigration for F0 {
type Cursor = ();
type Identifier = u8;
fn id() -> Self::Identifier {
3
}
fn step(
_cursor: Option<Self::Cursor>,
_meter: &mut WeightMeter,
) -> Result<Option<Self::Cursor>, SteppedMigrationError> {
log::info!("F0");
unhashed::put(&[3], &());
Err(SteppedMigrationError::Failed)
}
}
// Three migrations combined to execute in order:
type Triple = (M0, (M1, M2));
// Six migrations, just concatenating the ones from before:
type Hextuple = (Triple, Triple);
#[test]
fn singular_migrations_work() {
assert_eq!(M0::max_steps(), None);
assert_eq!(M1::max_steps(), Some(1));
assert_eq!(M2::max_steps(), Some(2));
assert_eq!(<(M0, M1)>::nth_max_steps(0), Some(None));
assert_eq!(<(M0, M1)>::nth_max_steps(1), Some(Some(1)));
assert_eq!(<(M0, M1, M2)>::nth_max_steps(2), Some(Some(2)));
assert_eq!(<(M0, M1)>::nth_max_steps(2), None);
}
#[test]
fn tuple_migrations_work() {
assert_eq!(<() as SteppedMigrations>::len(), 0);
assert_eq!(<((), ((), ())) as SteppedMigrations>::len(), 0);
assert_eq!(<Triple as SteppedMigrations>::len(), 3);
assert_eq!(<Hextuple as SteppedMigrations>::len(), 6);
// Check the IDs. The index specific functions all return an Option,
// to account for the out-of-range case.
assert_eq!(<Triple as SteppedMigrations>::nth_id(0), Some(0u8.encode()));
assert_eq!(<Triple as SteppedMigrations>::nth_id(1), Some(1u8.encode()));
assert_eq!(<Triple as SteppedMigrations>::nth_id(2), Some(2u8.encode()));
sp_io::TestExternalities::default().execute_with(|| {
for n in 0..3 {
<Triple as SteppedMigrations>::nth_step(
n,
Default::default(),
&mut WeightMeter::new(),
);
}
});
}
#[test]
fn integrity_test_works() {
sp_io::TestExternalities::default().execute_with(|| {
assert_ok!(<() as SteppedMigrations>::integrity_test());
assert_ok!(<M0 as SteppedMigrations>::integrity_test());
assert_ok!(<M1 as SteppedMigrations>::integrity_test());
assert_ok!(<M2 as SteppedMigrations>::integrity_test());
assert_ok!(<Triple as SteppedMigrations>::integrity_test());
assert_ok!(<Hextuple as SteppedMigrations>::integrity_test());
});
}
#[test]
fn transactional_rollback_works() {
sp_io::TestExternalities::default().execute_with(|| {
assert_ok!(<(M0, F0) as SteppedMigrations>::nth_transactional_step(
0,
Default::default(),
&mut WeightMeter::new()
)
.unwrap());
assert!(unhashed::exists(&[0]));
let _g = crate::StorageNoopGuard::new();
assert!(<(M0, F0) as SteppedMigrations>::nth_transactional_step(
1,
Default::default(),
&mut WeightMeter::new()
)
.unwrap()
.is_err());
assert!(<(F0, M1) as SteppedMigrations>::nth_transactional_step(
0,
Default::default(),
&mut WeightMeter::new()
)
.unwrap()
.is_err());
});
}
}