lib.rs

		#[serde(skip)]
		pub _config: sp_std::marker::PhantomData<T>,
	}

	#[pallet::genesis_build]
	impl<T: Config> BuildGenesisConfig for GenesisConfig<T> {
		fn build(&self) {
			<BlockHash<T>>::insert::<_, T::Hash>(BlockNumberFor::<T>::zero(), hash69());
			<ParentHash<T>>::put::<T::Hash>(hash69());
			<LastRuntimeUpgrade<T>>::put(LastRuntimeUpgradeInfo::from(T::Version::get()));
			<UpgradedToU32RefCount<T>>::put(true);
			<UpgradedToTripleRefCount<T>>::put(true);

			sp_io::storage::set(well_known_keys::EXTRINSIC_INDEX, &0u32.encode());
		}
	}

	#[pallet::validate_unsigned]
	impl<T: Config> sp_runtime::traits::ValidateUnsigned for Pallet<T> {
		type Call = Call<T>;
		fn validate_unsigned(_source: TransactionSource, call: &Self::Call) -> TransactionValidity {
			if let Call::apply_authorized_upgrade { ref code } = call {
				if let Ok(hash) = Self::validate_authorized_upgrade(&code[..]) {
					return Ok(ValidTransaction {
						priority: 100,
						requires: Vec::new(),
						provides: vec![hash.as_ref().to_vec()],
						longevity: TransactionLongevity::max_value(),
						propagate: true,
					})
				}
			}
			#[cfg(feature = "experimental")]
			if let Call::do_task { ref task } = call {
				if task.is_valid() {
					return Ok(ValidTransaction {
						priority: u64::max_value(),
						requires: Vec::new(),
						provides: vec![T::Hashing::hash_of(&task.encode()).as_ref().to_vec()],
						longevity: TransactionLongevity::max_value(),
						propagate: true,
					})
				}
			}
			Err(InvalidTransaction::Call.into())
		}
	}
}

pub type Key = Vec<u8>;
pub type KeyValue = (Vec<u8>, Vec<u8>);

/// A phase of a block's execution.
#[derive(Encode, Decode, RuntimeDebug, TypeInfo, MaxEncodedLen)]
#[cfg_attr(feature = "std", derive(Serialize, PartialEq, Eq, Clone))]
pub enum Phase {
	/// Applying an extrinsic.
	ApplyExtrinsic(u32),
	/// Finalizing the block.
	Finalization,
	/// Initializing the block.
	Initialization,
}

impl Default for Phase {
	fn default() -> Self {
		Self::Initialization
	}
}

/// Record of an event happening.
#[derive(Encode, Decode, RuntimeDebug, TypeInfo)]
#[cfg_attr(feature = "std", derive(Serialize, PartialEq, Eq, Clone))]
pub struct EventRecord<E: Parameter + Member, T> {
	/// The phase of the block it happened in.
	pub phase: Phase,
	/// The event itself.
	pub event: E,
	/// The list of the topics this event has.
	pub topics: Vec<T>,
}

// Create a Hash with 69 for each byte,
// only used to build genesis config.
fn hash69<T: AsMut<[u8]> + Default>() -> T {
	let mut h = T::default();
	h.as_mut().iter_mut().for_each(|byte| *byte = 69);
	h
}

/// This type alias represents an index of an event.
///
/// We use `u32` here because this index is used as index for `Events<T>`
/// which can't contain more than `u32::MAX` items.
type EventIndex = u32;

/// Type used to encode the number of references an account has.
pub type RefCount = u32;

/// Information of an account.
#[derive(Clone, Eq, PartialEq, Default, RuntimeDebug, Encode, Decode, TypeInfo, MaxEncodedLen)]
pub struct AccountInfo<Nonce, AccountData> {
	/// The number of transactions this account has sent.
	pub nonce: Nonce,
	/// The number of other modules that currently depend on this account's existence. The account
	/// cannot be reaped until this is zero.
	pub consumers: RefCount,
	/// The number of other modules that allow this account to exist. The account may not be reaped
	/// until this and `sufficients` are both zero.
	pub providers: RefCount,
	/// The number of modules that allow this account to exist for their own purposes only. The
	/// account may not be reaped until this and `providers` are both zero.
	pub sufficients: RefCount,
	/// The additional data that belongs to this account. Used to store the balance(s) in a lot of
	/// chains.
	pub data: AccountData,
}

/// Stores the `spec_version` and `spec_name` of when the last runtime upgrade
/// happened.
#[derive(sp_runtime::RuntimeDebug, Encode, Decode, TypeInfo)]
#[cfg_attr(feature = "std", derive(PartialEq))]
pub struct LastRuntimeUpgradeInfo {
	pub spec_version: codec::Compact<u32>,
	pub spec_name: sp_runtime::RuntimeString,
}

impl LastRuntimeUpgradeInfo {
	/// Returns if the runtime was upgraded in comparison of `self` and `current`.
	///
	/// Checks if either the `spec_version` increased or the `spec_name` changed.
	pub fn was_upgraded(&self, current: &sp_version::RuntimeVersion) -> bool {
		current.spec_version > self.spec_version.0 || current.spec_name != self.spec_name
	}
}

impl From<sp_version::RuntimeVersion> for LastRuntimeUpgradeInfo {
	fn from(version: sp_version::RuntimeVersion) -> Self {
		Self { spec_version: version.spec_version.into(), spec_name: version.spec_name }
	}
}

/// Ensure the origin is Root.
pub struct EnsureRoot<AccountId>(sp_std::marker::PhantomData<AccountId>);
impl<O: Into<Result<RawOrigin<AccountId>, O>> + From<RawOrigin<AccountId>>, AccountId>
	EnsureOrigin<O> for EnsureRoot<AccountId>
{
	type Success = ();
	fn try_origin(o: O) -> Result<Self::Success, O> {
		o.into().and_then(|o| match o {
			RawOrigin::Root => Ok(()),
			r => Err(O::from(r)),
		})
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn try_successful_origin() -> Result<O, ()> {
		Ok(O::from(RawOrigin::Root))
	}
}

impl_ensure_origin_with_arg_ignoring_arg! {
	impl< { O: .., AccountId: Decode, T } >
		EnsureOriginWithArg<O, T> for EnsureRoot<AccountId>
	{}
}

/// Ensure the origin is Root and return the provided `Success` value.
pub struct EnsureRootWithSuccess<AccountId, Success>(
	sp_std::marker::PhantomData<(AccountId, Success)>,
);
impl<
		O: Into<Result<RawOrigin<AccountId>, O>> + From<RawOrigin<AccountId>>,
		AccountId,
		Success: TypedGet,
	> EnsureOrigin<O> for EnsureRootWithSuccess<AccountId, Success>
{
	type Success = Success::Type;
	fn try_origin(o: O) -> Result<Self::Success, O> {
		o.into().and_then(|o| match o {
			RawOrigin::Root => Ok(Success::get()),
			r => Err(O::from(r)),
		})
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn try_successful_origin() -> Result<O, ()> {
		Ok(O::from(RawOrigin::Root))
	}
}

impl_ensure_origin_with_arg_ignoring_arg! {
	impl< { O: .., AccountId: Decode, Success: TypedGet, T } >
		EnsureOriginWithArg<O, T> for EnsureRootWithSuccess<AccountId, Success>
	{}
}

/// Ensure the origin is provided `Ensure` origin and return the provided `Success` value.
pub struct EnsureWithSuccess<Ensure, AccountId, Success>(
	sp_std::marker::PhantomData<(Ensure, AccountId, Success)>,
);

impl<
		O: Into<Result<RawOrigin<AccountId>, O>> + From<RawOrigin<AccountId>>,
		Ensure: EnsureOrigin<O>,
		AccountId,
		Success: TypedGet,
	> EnsureOrigin<O> for EnsureWithSuccess<Ensure, AccountId, Success>
{
	type Success = Success::Type;

	fn try_origin(o: O) -> Result<Self::Success, O> {
		Ensure::try_origin(o).map(|_| Success::get())
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn try_successful_origin() -> Result<O, ()> {
		Ensure::try_successful_origin()
	}
}

/// Ensure the origin is any `Signed` origin.
pub struct EnsureSigned<AccountId>(sp_std::marker::PhantomData<AccountId>);
impl<O: Into<Result<RawOrigin<AccountId>, O>> + From<RawOrigin<AccountId>>, AccountId: Decode>
	EnsureOrigin<O> for EnsureSigned<AccountId>
{
	type Success = AccountId;
	fn try_origin(o: O) -> Result<Self::Success, O> {
		o.into().and_then(|o| match o {
			RawOrigin::Signed(who) => Ok(who),
			r => Err(O::from(r)),
		})
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn try_successful_origin() -> Result<O, ()> {
		let zero_account_id =
			AccountId::decode(&mut TrailingZeroInput::zeroes()).map_err(|_| ())?;
		Ok(O::from(RawOrigin::Signed(zero_account_id)))
	}
}

impl_ensure_origin_with_arg_ignoring_arg! {
	impl< { O: .., AccountId: Decode, T } >
		EnsureOriginWithArg<O, T> for EnsureSigned<AccountId>
	{}
}

/// Ensure the origin is `Signed` origin from the given `AccountId`.
pub struct EnsureSignedBy<Who, AccountId>(sp_std::marker::PhantomData<(Who, AccountId)>);
impl<
		O: Into<Result<RawOrigin<AccountId>, O>> + From<RawOrigin<AccountId>>,
		Who: SortedMembers<AccountId>,
		AccountId: PartialEq + Clone + Ord + Decode,
	> EnsureOrigin<O> for EnsureSignedBy<Who, AccountId>
{
	type Success = AccountId;
	fn try_origin(o: O) -> Result<Self::Success, O> {
		o.into().and_then(|o| match o {
			RawOrigin::Signed(ref who) if Who::contains(who) => Ok(who.clone()),
			r => Err(O::from(r)),
		})
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn try_successful_origin() -> Result<O, ()> {
		let first_member = match Who::sorted_members().first() {
			Some(account) => account.clone(),
			None => AccountId::decode(&mut TrailingZeroInput::zeroes()).map_err(|_| ())?,
		};
		Ok(O::from(RawOrigin::Signed(first_member)))
	}
}

impl_ensure_origin_with_arg_ignoring_arg! {
	impl< { O: .., Who: SortedMembers<AccountId>, AccountId: PartialEq + Clone + Ord + Decode, T } >
		EnsureOriginWithArg<O, T> for EnsureSignedBy<Who, AccountId>
	{}
}

/// Ensure the origin is `None`. i.e. unsigned transaction.
pub struct EnsureNone<AccountId>(sp_std::marker::PhantomData<AccountId>);
impl<O: Into<Result<RawOrigin<AccountId>, O>> + From<RawOrigin<AccountId>>, AccountId>
	EnsureOrigin<O> for EnsureNone<AccountId>
{
	type Success = ();
	fn try_origin(o: O) -> Result<Self::Success, O> {
		o.into().and_then(|o| match o {
			RawOrigin::None => Ok(()),
			r => Err(O::from(r)),
		})
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn try_successful_origin() -> Result<O, ()> {
		Ok(O::from(RawOrigin::None))
	}
}

impl_ensure_origin_with_arg_ignoring_arg! {
	impl< { O: .., AccountId, T } >
		EnsureOriginWithArg<O, T> for EnsureNone<AccountId>
	{}
}

/// Always fail.
pub struct EnsureNever<Success>(sp_std::marker::PhantomData<Success>);
impl<O, Success> EnsureOrigin<O> for EnsureNever<Success> {
	type Success = Success;
	fn try_origin(o: O) -> Result<Self::Success, O> {
		Err(o)
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn try_successful_origin() -> Result<O, ()> {
		Err(())
	}
}

impl_ensure_origin_with_arg_ignoring_arg! {
	impl< { O, Success, T } >
		EnsureOriginWithArg<O, T> for EnsureNever<Success>
	{}
}

#[docify::export]
/// Ensure that the origin `o` represents a signed extrinsic (i.e. transaction).
/// Returns `Ok` with the account that signed the extrinsic or an `Err` otherwise.
pub fn ensure_signed<OuterOrigin, AccountId>(o: OuterOrigin) -> Result<AccountId, BadOrigin>
where
	OuterOrigin: Into<Result<RawOrigin<AccountId>, OuterOrigin>>,
{
	match o.into() {
		Ok(RawOrigin::Signed(t)) => Ok(t),
		_ => Err(BadOrigin),
	}
}

/// Ensure that the origin `o` represents either a signed extrinsic (i.e. transaction) or the root.
/// Returns `Ok` with the account that signed the extrinsic, `None` if it was root,  or an `Err`
/// otherwise.
pub fn ensure_signed_or_root<OuterOrigin, AccountId>(
	o: OuterOrigin,
) -> Result<Option<AccountId>, BadOrigin>
where
	OuterOrigin: Into<Result<RawOrigin<AccountId>, OuterOrigin>>,
{
	match o.into() {
		Ok(RawOrigin::Root) => Ok(None),
		Ok(RawOrigin::Signed(t)) => Ok(Some(t)),
		_ => Err(BadOrigin),
	}
}

/// Ensure that the origin `o` represents the root. Returns `Ok` or an `Err` otherwise.
pub fn ensure_root<OuterOrigin, AccountId>(o: OuterOrigin) -> Result<(), BadOrigin>
where
	OuterOrigin: Into<Result<RawOrigin<AccountId>, OuterOrigin>>,
{
	match o.into() {
		Ok(RawOrigin::Root) => Ok(()),
		_ => Err(BadOrigin),
	}
}

/// Ensure that the origin `o` represents an unsigned extrinsic. Returns `Ok` or an `Err` otherwise.
pub fn ensure_none<OuterOrigin, AccountId>(o: OuterOrigin) -> Result<(), BadOrigin>
where
	OuterOrigin: Into<Result<RawOrigin<AccountId>, OuterOrigin>>,
{
	match o.into() {
		Ok(RawOrigin::None) => Ok(()),
		_ => Err(BadOrigin),
	}
}

/// Reference status; can be either referenced or unreferenced.
#[derive(RuntimeDebug)]
pub enum RefStatus {
	Referenced,
	Unreferenced,
}

/// Some resultant status relevant to incrementing a provider/self-sufficient reference.
#[derive(Eq, PartialEq, RuntimeDebug)]
pub enum IncRefStatus {
	/// Account was created.
	Created,
	/// Account already existed.
	Existed,
}

/// Some resultant status relevant to decrementing a provider/self-sufficient reference.
#[derive(Eq, PartialEq, RuntimeDebug)]
pub enum DecRefStatus {
	/// Account was destroyed.
	Reaped,
	/// Account still exists.
	Exists,
}

impl<T: Config> Pallet<T> {
	/// Returns the `spec_version` of the last runtime upgrade.
	///
	/// This function is useful for writing guarded runtime migrations in the runtime. A runtime
	/// migration can use the `spec_version` to ensure that it isn't applied twice. This works
	/// similar as the storage version for pallets.
	///
	/// This functions returns the `spec_version` of the last runtime upgrade while executing the
	/// runtime migrations
	/// [`on_runtime_upgrade`](frame_support::traits::OnRuntimeUpgrade::on_runtime_upgrade)
	/// function. After all migrations are executed, this will return the `spec_version` of the
	/// current runtime until there is another runtime upgrade.
	///
	/// Example:
	#[doc = docify::embed!("src/tests.rs", last_runtime_upgrade_spec_version_usage)]
	pub fn last_runtime_upgrade_spec_version() -> u32 {
		LastRuntimeUpgrade::<T>::get().map_or(0, |l| l.spec_version.0)
	}

	/// Returns true if the given account exists.
	pub fn account_exists(who: &T::AccountId) -> bool {
		Account::<T>::contains_key(who)
	}

	/// Write code to the storage and emit related events and digest items.
	///
	/// Note this function almost never should be used directly. It is exposed
	/// for `OnSetCode` implementations that defer actual code being written to
	/// the storage (for instance in case of parachains).
	pub fn update_code_in_storage(code: &[u8]) {
		storage::unhashed::put_raw(well_known_keys::CODE, code);
		Self::deposit_log(generic::DigestItem::RuntimeEnvironmentUpdated);
		Self::deposit_event(Event::CodeUpdated);
	}

	/// Whether all inherents have been applied.
	pub fn inherents_applied() -> bool {
		InherentsApplied::<T>::get()
	}

	/// Note that all inherents have been applied.
	///
	/// Should be called immediately after all inherents have been applied. Must be called at least
	/// once per block.
	pub fn note_inherents_applied() {
		InherentsApplied::<T>::put(true);
	}

	/// Increment the reference counter on an account.
	#[deprecated = "Use `inc_consumers` instead"]
	pub fn inc_ref(who: &T::AccountId) {
		let _ = Self::inc_consumers(who);
	}

	/// Decrement the reference counter on an account. This *MUST* only be done once for every time
	/// you called `inc_consumers` on `who`.
	#[deprecated = "Use `dec_consumers` instead"]
	pub fn dec_ref(who: &T::AccountId) {
		let _ = Self::dec_consumers(who);
	}

	/// The number of outstanding references for the account `who`.
	#[deprecated = "Use `consumers` instead"]
	pub fn refs(who: &T::AccountId) -> RefCount {
		Self::consumers(who)
	}

	/// True if the account has no outstanding references.
	#[deprecated = "Use `!is_provider_required` instead"]
	pub fn allow_death(who: &T::AccountId) -> bool {
		!Self::is_provider_required(who)
	}

	/// Increment the provider reference counter on an account.
	pub fn inc_providers(who: &T::AccountId) -> IncRefStatus {
		Account::<T>::mutate(who, |a| {
			if a.providers == 0 && a.sufficients == 0 {
				// Account is being created.
				a.providers = 1;
				Self::on_created_account(who.clone(), a);
				IncRefStatus::Created
			} else {
				a.providers = a.providers.saturating_add(1);
				IncRefStatus::Existed
			}
		})
	}

	/// Decrement the provider reference counter on an account.
	///
	/// This *MUST* only be done once for every time you called `inc_providers` on `who`.
	pub fn dec_providers(who: &T::AccountId) -> Result<DecRefStatus, DispatchError> {
		Account::<T>::try_mutate_exists(who, |maybe_account| {
			if let Some(mut account) = maybe_account.take() {
				if account.providers == 0 {
					// Logic error - cannot decrement beyond zero.
					log::error!(
						target: LOG_TARGET,
						"Logic error: Unexpected underflow in reducing provider",
					);
					account.providers = 1;
				}
				match (account.providers, account.consumers, account.sufficients) {
					(1, 0, 0) => {
						// No providers left (and no consumers) and no sufficients. Account dead.

						Pallet::<T>::on_killed_account(who.clone());
						Ok(DecRefStatus::Reaped)
					},
					(1, c, _) if c > 0 => {
						// Cannot remove last provider if there are consumers.
						Err(DispatchError::ConsumerRemaining)
					},
					(x, _, _) => {
						// Account will continue to exist as there is either > 1 provider or
						// > 0 sufficients.
						account.providers = x - 1;
						*maybe_account = Some(account);
						Ok(DecRefStatus::Exists)
					},
				}
			} else {
				log::error!(
					target: LOG_TARGET,
					"Logic error: Account already dead when reducing provider",
				);
				Ok(DecRefStatus::Reaped)
			}
		})
	}

	/// Increment the self-sufficient reference counter on an account.
	pub fn inc_sufficients(who: &T::AccountId) -> IncRefStatus {
		Account::<T>::mutate(who, |a| {
			if a.providers + a.sufficients == 0 {
				// Account is being created.
				a.sufficients = 1;
				Self::on_created_account(who.clone(), a);
				IncRefStatus::Created
			} else {
				a.sufficients = a.sufficients.saturating_add(1);
				IncRefStatus::Existed
			}
		})
	}

	/// Decrement the sufficients reference counter on an account.
	///
	/// This *MUST* only be done once for every time you called `inc_sufficients` on `who`.
	pub fn dec_sufficients(who: &T::AccountId) -> DecRefStatus {
		Account::<T>::mutate_exists(who, |maybe_account| {
			if let Some(mut account) = maybe_account.take() {
				if account.sufficients == 0 {
					// Logic error - cannot decrement beyond zero.
					log::error!(
						target: LOG_TARGET,
						"Logic error: Unexpected underflow in reducing sufficients",
					);
				}
				match (account.sufficients, account.providers) {
					(0, 0) | (1, 0) => {
						Pallet::<T>::on_killed_account(who.clone());
						DecRefStatus::Reaped
					},
					(x, _) => {
						account.sufficients = x - 1;
						*maybe_account = Some(account);
						DecRefStatus::Exists
					},
				}
			} else {
				log::error!(
					target: LOG_TARGET,
					"Logic error: Account already dead when reducing provider",
				);
				DecRefStatus::Reaped
			}
		})
	}

	/// The number of outstanding provider references for the account `who`.
	pub fn providers(who: &T::AccountId) -> RefCount {
		Account::<T>::get(who).providers
	}

	/// The number of outstanding sufficient references for the account `who`.
	pub fn sufficients(who: &T::AccountId) -> RefCount {
		Account::<T>::get(who).sufficients
	}

	/// The number of outstanding provider and sufficient references for the account `who`.
	pub fn reference_count(who: &T::AccountId) -> RefCount {
		let a = Account::<T>::get(who);
		a.providers + a.sufficients
	}

	/// Increment the reference counter on an account.
	///
	/// The account `who`'s `providers` must be non-zero and the current number of consumers must
	/// be less than `MaxConsumers::max_consumers()` or this will return an error.
	pub fn inc_consumers(who: &T::AccountId) -> Result<(), DispatchError> {
		Account::<T>::try_mutate(who, |a| {
			if a.providers > 0 {
				if a.consumers < T::MaxConsumers::max_consumers() {
					a.consumers = a.consumers.saturating_add(1);
					Ok(())
				} else {
					Err(DispatchError::TooManyConsumers)
				}
			} else {
				Err(DispatchError::NoProviders)
			}
		})
	}

	/// Increment the reference counter on an account, ignoring the `MaxConsumers` limits.
	///
	/// The account `who`'s `providers` must be non-zero or this will return an error.
	pub fn inc_consumers_without_limit(who: &T::AccountId) -> Result<(), DispatchError> {
		Account::<T>::try_mutate(who, |a| {
			if a.providers > 0 {
				a.consumers = a.consumers.saturating_add(1);
				Ok(())
			} else {
				Err(DispatchError::NoProviders)
			}
		})
	}

	/// Decrement the reference counter on an account. This *MUST* only be done once for every time
	/// you called `inc_consumers` on `who`.
	pub fn dec_consumers(who: &T::AccountId) {
		Account::<T>::mutate(who, |a| {
			if a.consumers > 0 {
				a.consumers -= 1;
			} else {
				log::error!(
					target: LOG_TARGET,
					"Logic error: Unexpected underflow in reducing consumer",
				);
			}
		})
	}

	/// The number of outstanding references for the account `who`.
	pub fn consumers(who: &T::AccountId) -> RefCount {
		Account::<T>::get(who).consumers
	}

	/// True if the account has some outstanding consumer references.
	pub fn is_provider_required(who: &T::AccountId) -> bool {
		Account::<T>::get(who).consumers != 0
	}

	/// True if the account has no outstanding consumer references or more than one provider.
	pub fn can_dec_provider(who: &T::AccountId) -> bool {
		let a = Account::<T>::get(who);
		a.consumers == 0 || a.providers > 1
	}

	/// True if the account has at least one provider reference and adding `amount` consumer
	/// references would not take it above the the maximum.
	pub fn can_accrue_consumers(who: &T::AccountId, amount: u32) -> bool {
		let a = Account::<T>::get(who);
		match a.consumers.checked_add(amount) {
			Some(c) => a.providers > 0 && c <= T::MaxConsumers::max_consumers(),
			None => false,
		}
	}

	/// True if the account has at least one provider reference and fewer consumer references than
	/// the maximum.
	pub fn can_inc_consumer(who: &T::AccountId) -> bool {
		Self::can_accrue_consumers(who, 1)
	}

	/// Deposits an event into this block's event record.
	///
	/// NOTE: Events not registered at the genesis block and quietly omitted.
	pub fn deposit_event(event: impl Into<T::RuntimeEvent>) {
		Self::deposit_event_indexed(&[], event.into());
	}

	/// Deposits an event into this block's event record adding this event
	/// to the corresponding topic indexes.
	///
	/// This will update storage entries that correspond to the specified topics.
	/// It is expected that light-clients could subscribe to this topics.
	///
	/// NOTE: Events not registered at the genesis block and quietly omitted.
	pub fn deposit_event_indexed(topics: &[T::Hash], event: T::RuntimeEvent) {
		let block_number = Self::block_number();

		// Don't populate events on genesis.
		if block_number.is_zero() {
			return
		}

		let phase = ExecutionPhase::<T>::get().unwrap_or_default();
		let event = EventRecord { phase, event, topics: topics.to_vec() };

		// Index of the event to be added.
		let event_idx = {
			let old_event_count = EventCount::<T>::get();
			let new_event_count = match old_event_count.checked_add(1) {
				// We've reached the maximum number of events at this block, just
				// don't do anything and leave the event_count unaltered.
				None => return,
				Some(nc) => nc,
			};
			EventCount::<T>::put(new_event_count);
			old_event_count
		};

		Events::<T>::append(event);

		for topic in topics {
			<EventTopics<T>>::append(topic, &(block_number, event_idx));
		}
	}

	/// Gets the index of extrinsic that is currently executing.
	pub fn extrinsic_index() -> Option<u32> {
		storage::unhashed::get(well_known_keys::EXTRINSIC_INDEX)
	}

	/// Gets extrinsics count.
	pub fn extrinsic_count() -> u32 {
		ExtrinsicCount::<T>::get().unwrap_or_default()
	}

	pub fn all_extrinsics_len() -> u32 {
		AllExtrinsicsLen::<T>::get().unwrap_or_default()
	}

	/// Inform the system pallet of some additional weight that should be accounted for, in the
	/// current block.
	///
	/// NOTE: use with extra care; this function is made public only be used for certain pallets
	/// that need it. A runtime that does not have dynamic calls should never need this and should
	/// stick to static weights. A typical use case for this is inner calls or smart contract calls.
	/// Furthermore, it only makes sense to use this when it is presumably  _cheap_ to provide the
	/// argument `weight`; In other words, if this function is to be used to account for some
	/// unknown, user provided call's weight, it would only make sense to use it if you are sure you
	/// can rapidly compute the weight of the inner call.
	///
	/// Even more dangerous is to note that this function does NOT take any action, if the new sum
	/// of block weight is more than the block weight limit. This is what the _unchecked_.
	///
	/// Another potential use-case could be for the `on_initialize` and `on_finalize` hooks.
	pub fn register_extra_weight_unchecked(weight: Weight, class: DispatchClass) {
		BlockWeight::<T>::mutate(|current_weight| {
			current_weight.accrue(weight, class);
		});
	}

	/// Start the execution of a particular block.
	pub fn initialize(number: &BlockNumberFor<T>, parent_hash: &T::Hash, digest: &generic::Digest) {
		// populate environment
		ExecutionPhase::<T>::put(Phase::Initialization);
		storage::unhashed::put(well_known_keys::EXTRINSIC_INDEX, &0u32);
		let entropy = (b"frame_system::initialize", parent_hash).using_encoded(blake2_256);
		storage::unhashed::put_raw(well_known_keys::INTRABLOCK_ENTROPY, &entropy[..]);
		<Number<T>>::put(number);
		<Digest<T>>::put(digest);
		<ParentHash<T>>::put(parent_hash);
		<BlockHash<T>>::insert(*number - One::one(), parent_hash);
		<InherentsApplied<T>>::kill();

		// Remove previous block data from storage
		BlockWeight::<T>::kill();
	}

	/// Remove temporary "environment" entries in storage, compute the storage root and return the
	/// resulting header for this block.
	pub fn finalize() -> HeaderFor<T> {
		log::debug!(
			target: LOG_TARGET,
			"[{:?}] {} extrinsics, length: {} (normal {}%, op: {}%, mandatory {}%) / normal weight:\
			 {} ({}%) op weight {} ({}%) / mandatory weight {} ({}%)",
			Self::block_number(),
			Self::extrinsic_index().unwrap_or_default(),
			Self::all_extrinsics_len(),
			sp_runtime::Percent::from_rational(
				Self::all_extrinsics_len(),
				*T::BlockLength::get().max.get(DispatchClass::Normal)
			).deconstruct(),
			sp_runtime::Percent::from_rational(
				Self::all_extrinsics_len(),
				*T::BlockLength::get().max.get(DispatchClass::Operational)
			).deconstruct(),
			sp_runtime::Percent::from_rational(
				Self::all_extrinsics_len(),
				*T::BlockLength::get().max.get(DispatchClass::Mandatory)
			).deconstruct(),
			Self::block_weight().get(DispatchClass::Normal),
			sp_runtime::Percent::from_rational(
				Self::block_weight().get(DispatchClass::Normal).ref_time(),
				T::BlockWeights::get().get(DispatchClass::Normal).max_total.unwrap_or(Bounded::max_value()).ref_time()
			).deconstruct(),
			Self::block_weight().get(DispatchClass::Operational),
			sp_runtime::Percent::from_rational(
				Self::block_weight().get(DispatchClass::Operational).ref_time(),
				T::BlockWeights::get().get(DispatchClass::Operational).max_total.unwrap_or(Bounded::max_value()).ref_time()
			).deconstruct(),
			Self::block_weight().get(DispatchClass::Mandatory),
			sp_runtime::Percent::from_rational(
				Self::block_weight().get(DispatchClass::Mandatory).ref_time(),
				T::BlockWeights::get().get(DispatchClass::Mandatory).max_total.unwrap_or(Bounded::max_value()).ref_time()
			).deconstruct(),
		);
		ExecutionPhase::<T>::kill();
		AllExtrinsicsLen::<T>::kill();
		storage::unhashed::kill(well_known_keys::INTRABLOCK_ENTROPY);
		InherentsApplied::<T>::kill();

		// The following fields
		//
		// - <Events<T>>
		// - <EventCount<T>>
		// - <EventTopics<T>>
		// - <Number<T>>
		// - <ParentHash<T>>
		// - <Digest<T>>
		//
		// stay to be inspected by the client and will be cleared by `Self::initialize`.
		let number = <Number<T>>::get();
		let parent_hash = <ParentHash<T>>::get();
		let digest = <Digest<T>>::get();

		let extrinsics = (0..ExtrinsicCount::<T>::take().unwrap_or_default())
			.map(ExtrinsicData::<T>::take)
			.collect();
		let extrinsics_root = extrinsics_data_root::<T::Hashing>(extrinsics);

		// move block hash pruning window by one block
		let block_hash_count = T::BlockHashCount::get();
		let to_remove = number.saturating_sub(block_hash_count).saturating_sub(One::one());

		// keep genesis hash
		if !to_remove.is_zero() {
			<BlockHash<T>>::remove(to_remove);
		}

		let version = T::Version::get().state_version();
		let storage_root = T::Hash::decode(&mut &sp_io::storage::root(version)[..])
			.expect("Node is configured to use the same hash; qed");

		HeaderFor::<T>::new(number, extrinsics_root, storage_root, parent_hash, digest)
	}

	/// Deposits a log and ensures it matches the block's log data.
	pub fn deposit_log(item: generic::DigestItem) {
		<Digest<T>>::append(item);
	}

	/// Get the basic externalities for this pallet, useful for tests.
	#[cfg(any(feature = "std", test))]
	pub fn externalities() -> TestExternalities {
		TestExternalities::new(sp_core::storage::Storage {
			top: map![
				<BlockHash<T>>::hashed_key_for(BlockNumberFor::<T>::zero()) => [69u8; 32].encode(),
				<Number<T>>::hashed_key().to_vec() => BlockNumberFor::<T>::one().encode(),
				<ParentHash<T>>::hashed_key().to_vec() => [69u8; 32].encode()
			],
			children_default: map![],
		})
	}

	/// Get the current events deposited by the runtime.
	///
	/// NOTE: This should only be used in tests. Reading events from the runtime can have a large
	/// impact on the PoV size of a block. Users should use alternative and well bounded storage
	/// items for any behavior like this.
	///
	/// NOTE: Events not registered at the genesis block and quietly omitted.
	#[cfg(any(feature = "std", feature = "runtime-benchmarks", test))]
	pub fn events() -> Vec<EventRecord<T::RuntimeEvent, T::Hash>> {
		// Dereferencing the events here is fine since we are not in the memory-restricted runtime.
		Self::read_events_no_consensus().map(|e| *e).collect()
	}

	/// Get a single event at specified index.
	///
	/// Should only be called if you know what you are doing and outside of the runtime block
	/// execution else it can have a large impact on the PoV size of a block.
	pub fn event_no_consensus(index: usize) -> Option<T::RuntimeEvent> {
		Self::read_events_no_consensus().nth(index).map(|e| e.event.clone())
	}

	/// Get the current events deposited by the runtime.
	///
	/// Should only be called if you know what you are doing and outside of the runtime block
	/// execution else it can have a large impact on the PoV size of a block.
	pub fn read_events_no_consensus(
	) -> impl sp_std::iter::Iterator<Item = Box<EventRecord<T::RuntimeEvent, T::Hash>>> {
		Events::<T>::stream_iter()
	}

	/// Read and return the events of a specific pallet, as denoted by `E`.
	///
	/// This is useful for a pallet that wishes to read only the events it has deposited into
	/// `frame_system` using the standard `fn deposit_event`.
	pub fn read_events_for_pallet<E>() -> Vec<E>
	where
		T::RuntimeEvent: TryInto<E>,
	{
		Events::<T>::get()
			.into_iter()
			.map(|er| er.event)
			.filter_map(|e| e.try_into().ok())
			.collect::<_>()
	}

	/// Set the block number to something in particular. Can be used as an alternative to
	/// `initialize` for tests that don't need to bother with the other environment entries.
	#[cfg(any(feature = "std", feature = "runtime-benchmarks", test))]
	pub fn set_block_number(n: BlockNumberFor<T>) {
		<Number<T>>::put(n);
	}

	/// Sets the index of extrinsic that is currently executing.
	#[cfg(any(feature = "std", test))]
	pub fn set_extrinsic_index(extrinsic_index: u32) {
		storage::unhashed::put(well_known_keys::EXTRINSIC_INDEX, &extrinsic_index)
	}

	/// Set the parent hash number to something in particular. Can be used as an alternative to
	/// `initialize` for tests that don't need to bother with the other environment entries.
	#[cfg(any(feature = "std", test))]
	pub fn set_parent_hash(n: T::Hash) {
		<ParentHash<T>>::put(n);
	}

	/// Set the current block weight. This should only be used in some integration tests.
	#[cfg(any(feature = "std", test))]
	pub fn set_block_consumed_resources(weight: Weight, len: usize) {
		BlockWeight::<T>::mutate(|current_weight| {
			current_weight.set(weight, DispatchClass::Normal)
		});
		AllExtrinsicsLen::<T>::put(len as u32);
	}

	/// Reset events.
	///
	/// This needs to be used in prior calling [`initialize`](Self::initialize) for each new block
	/// to clear events from previous block.
	pub fn reset_events() {
		<Events<T>>::kill();
		EventCount::<T>::kill();
		let _ = <EventTopics<T>>::clear(u32::max_value(), None);
	}

	/// Assert the given `event` exists.
	///
	/// NOTE: Events not registered at the genesis block and quietly omitted.
	#[cfg(any(feature = "std", feature = "runtime-benchmarks", test))]
	pub fn assert_has_event(event: T::RuntimeEvent) {
		let events = Self::events();
		assert!(
			events.iter().any(|record| record.event == event),
			"expected event {event:?} not found in events {events:?}",
		);
	}

	/// Assert the last event equal to the given `event`.
	///
	/// NOTE: Events not registered at the genesis block and quietly omitted.
	#[cfg(any(feature = "std", feature = "runtime-benchmarks", test))]
	pub fn assert_last_event(event: T::RuntimeEvent) {
		let last_event = Self::events().last().expect("events expected").event.clone();
		assert_eq!(
			last_event, event,
			"expected event {event:?} is not equal to the last event {last_event:?}",
		);
	}

	/// Return the chain's current runtime version.
	pub fn runtime_version() -> RuntimeVersion {
		T::Version::get()
	}

	/// Retrieve the account transaction counter from storage.
	pub fn account_nonce(who: impl EncodeLike<T::AccountId>) -> T::Nonce {
		Account::<T>::get(who).nonce
	}

	/// Increment a particular account's nonce by 1.
	pub fn inc_account_nonce(who: impl EncodeLike<T::AccountId>) {
		Account::<T>::mutate(who, |a| a.nonce += T::Nonce::one());
	}

	/// Note what the extrinsic data of the current extrinsic index is.
	///
	/// This is required to be called before applying an extrinsic. The data will used
	/// in [`Self::finalize`] to calculate the correct extrinsics root.
	pub fn note_extrinsic(encoded_xt: Vec<u8>) {
		ExtrinsicData::<T>::insert(Self::extrinsic_index().unwrap_or_default(), encoded_xt);
	}