git.delta.rocks / unique-network / refs/commits / d7617e10f821

1// Copyright 2019-2022 Unique Network (Gibraltar) Ltd.2// This file is part of Unique Network.34// Unique Network is free software: you can redistribute it and/or modify5// it under the terms of the GNU General Public License as published by6// the Free Software Foundation, either version 3 of the License, or7// (at your option) any later version.89// Unique Network is distributed in the hope that it will be useful,10// but WITHOUT ANY WARRANTY; without even the implied warranty of11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the12// GNU General Public License for more details.1314// You should have received a copy of the GNU General Public License15// along with Unique Network. If not, see <http://www.gnu.org/licenses/>.1617// Original license:18// This file is part of Substrate.1920// Copyright (C) 2017-2022 Parity Technologies (UK) Ltd.21// SPDX-License-Identifier: Apache-2.02223// Licensed under the Apache License, Version 2.0 (the "License");24// you may not use this file except in compliance with the License.25// You may obtain a copy of the License at26//27// 	http://www.apache.org/licenses/LICENSE-2.028//29// Unless required by applicable law or agreed to in writing, software30// distributed under the License is distributed on an "AS IS" BASIS,31// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.32// See the License for the specific language governing permissions and33// limitations under the License.3435//! # Scheduler36//! A Pallet for scheduling dispatches.37//!38//! - [`Config`]39//! - [`Call`]40//! - [`Pallet`]41//!42//! ## Overview43//!44//! This Pallet exposes capabilities for scheduling dispatches to occur at a45//! specified block number or at a specified period. These scheduled dispatches46//! may be named or anonymous and may be canceled.47//!48//! **NOTE:** The scheduled calls will be dispatched with the default filter49//! for the origin: namely `frame_system::Config::BaseCallFilter` for all origin50//! except root which will get no filter. And not the filter contained in origin51//! use to call `fn schedule`.52//!53//! If a call is scheduled using proxy or whatever mecanism which adds filter,54//! then those filter will not be used when dispatching the schedule call.55//!56//! ## Interface57//!58//! ### Dispatchable Functions59//!60//! * `schedule` - schedule a dispatch, which may be periodic, to occur at a specified block and61//!   with a specified priority.62//! * `cancel` - cancel a scheduled dispatch, specified by block number and index.63//! * `schedule_named` - augments the `schedule` interface with an additional `Vec<u8>` parameter64//!   that can be used for identification.65//! * `cancel_named` - the named complement to the cancel function.6667// Ensure we're `no_std` when compiling for Wasm.68#![cfg_attr(not(feature = "std"), no_std)]6970#[cfg(feature = "runtime-benchmarks")]71mod benchmarking;72#[cfg(test)]73mod mock;74#[cfg(test)]75mod tests;76pub mod weights;7778use codec::{Codec, Decode, Encode, MaxEncodedLen};79use frame_support::{80	dispatch::{81		DispatchError, DispatchResult, Dispatchable, GetDispatchInfo, Parameter, RawOrigin,82	},83	ensure,84	traits::{85		schedule::{self, DispatchTime},86		EnsureOrigin, Get, IsType, OriginTrait,87		PalletInfoAccess, PrivilegeCmp, StorageVersion,88        PreimageProvider, PreimageRecipient, ConstU32,89	},90	weights::Weight,91};9293use frame_system::{self as system};94use scale_info::TypeInfo;95use sp_io::hashing::blake2_256;96use sp_runtime::{97	traits::{BadOrigin, One, Saturating, Zero, Hash},98	BoundedVec, RuntimeDebug,99};100use sp_std::{borrow::Borrow, cmp::Ordering, marker::PhantomData, prelude::*};101pub use weights::WeightInfo;102103pub use pallet::*;104105/// Just a simple index for naming period tasks.106pub type PeriodicIndex = u32;107/// The location of a scheduled task that can be used to remove it.108pub type TaskAddress<BlockNumber> = (BlockNumber, u32);109110pub type EncodedCall = BoundedVec<u8, ConstU32<128>>;111112#[derive(Clone, Eq, PartialEq, Encode, Decode, RuntimeDebug, TypeInfo, MaxEncodedLen)]113#[scale_info(skip_type_params(T))]114pub enum ScheduledCall<T: Config> {115    Inline(EncodedCall),116    PreimageLookup {117        hash: T::Hash,118        unbounded_len: u32,119    },120}121122impl<T: Config> ScheduledCall<T> {123	pub fn new(call: <T as Config>::Call) -> Result<Self, DispatchError> {124		let encoded = call.encode();125		let len = encoded.len();126127		match EncodedCall::try_from(encoded.clone()) {128			Ok(bounded) => Ok(Self::Inline(bounded)),129			Err(_) => {130				let hash = <T as system::Config>::Hashing::hash_of(&encoded);131				<T as Config>::Preimages::note_preimage(encoded.try_into().map_err(|_| <Error<T>>::TooBigScheduledCall)?);132133				Ok(Self::PreimageLookup { hash, unbounded_len: len as u32 })134			}135		}136	}137138	/// The maximum length of the lookup that is needed to peek `Self`.139	pub fn lookup_len(&self) -> Option<u32> {140		match self {141			Self::Inline(..) => None,142			Self::PreimageLookup { unbounded_len, .. } => Some(*unbounded_len),143		}144	}145146	/// Returns whether the image will require a lookup to be peeked.147	pub fn lookup_needed(&self) -> bool {148		match self {149			Self::Inline(_) => false,150			Self::PreimageLookup { .. } => true,151		}152	}153154	fn decode(mut data: &[u8]) -> Result<<T as Config>::Call, DispatchError> {155		<T as Config>::Call::decode(&mut data)156				.map_err(|_| <Error<T>>::ScheduledCallCorrupted.into())157	}158}159160pub trait SchedulerPreimages<T: Config>: PreimageRecipient<T::Hash> {161    fn drop(call: &ScheduledCall<T>);162163	fn peek(call: &ScheduledCall<T>) -> Result<(<T as pallet::Config>::Call, Option<u32>), DispatchError>;164165	/// Convert the given scheduled `call` value back into its original instance. If successful,166	/// `drop` any data backing it. This will not break the realisability of independently167	/// created instances of `ScheduledCall` which happen to have identical data.168	fn realize(call: &ScheduledCall<T>) -> Result<(<T as pallet::Config>::Call, Option<u32>), DispatchError>;169}170171impl<T: Config, PP: PreimageRecipient<T::Hash>> SchedulerPreimages<T> for PP {172    fn drop(call: &ScheduledCall<T>) {173        match call {174            ScheduledCall::Inline(_) => {},175            ScheduledCall::PreimageLookup { hash, .. } => Self::unrequest_preimage(hash),176        }177    }178179	fn peek(call: &ScheduledCall<T>) -> Result<(<T as pallet::Config>::Call, Option<u32>), DispatchError> {180		match call {181			ScheduledCall::Inline(data) => Ok((ScheduledCall::<T>::decode(data)?, None)),182			ScheduledCall::PreimageLookup { hash, unbounded_len } => {183				let (preimage, len) = Self::get_preimage(hash)184					.ok_or(<Error<T>>::PreimageNotFound)185					.map(|preimage| (preimage, *unbounded_len))?;186187				Ok((ScheduledCall::<T>::decode(preimage.as_slice())?, Some(len)))188			},189		}190	}191192	fn realize(call: &ScheduledCall<T>) -> Result<(<T as pallet::Config>::Call, Option<u32>), DispatchError> {193		let r = Self::peek(call)?;194		Self::drop(call);195		Ok(r)196	}197}198199pub type TaskName = [u8; 32];200201/// Information regarding an item to be executed in the future.202#[cfg_attr(any(feature = "std", test), derive(PartialEq, Eq))]203#[derive(Clone, RuntimeDebug, Encode, Decode, MaxEncodedLen, TypeInfo)]204pub struct Scheduled<Name, Call, BlockNumber, PalletsOrigin, AccountId> {205	/// The unique identity for this task, if there is one.206	maybe_id: Option<Name>,207208    /// This task's priority.209	priority: schedule::Priority,210211    /// The call to be dispatched.212	call: Call,213214    /// If the call is periodic, then this points to the information concerning that.215	maybe_periodic: Option<schedule::Period<BlockNumber>>,216217    /// The origin with which to dispatch the call.218	origin: PalletsOrigin,219	_phantom: PhantomData<AccountId>,220}221222pub type ScheduledOf<T> = Scheduled<223	TaskName,224	ScheduledCall<T>,225	<T as frame_system::Config>::BlockNumber,226	<T as Config>::PalletsOrigin,227	<T as frame_system::Config>::AccountId,228>;229230struct WeightCounter {231	used: Weight,232	limit: Weight,233}234235impl WeightCounter {236	fn check_accrue(&mut self, w: Weight) -> bool {237		let test = self.used.saturating_add(w);238		if test > self.limit {239			false240		} else {241			self.used = test;242			true243		}244	}245246	fn can_accrue(&mut self, w: Weight) -> bool {247		self.used.saturating_add(w) <= self.limit248	}249}250251pub(crate) trait MarginalWeightInfo: WeightInfo {252	fn service_task(maybe_lookup_len: Option<usize>, named: bool, periodic: bool) -> Weight {253		let base = Self::service_task_base();254		let mut total = match maybe_lookup_len {255			None => base,256			Some(l) => Self::service_task_fetched(l as u32),257		};258		if named {259			total.saturating_accrue(Self::service_task_named().saturating_sub(base));260		}261		if periodic {262			total.saturating_accrue(Self::service_task_periodic().saturating_sub(base));263		}264		total265	}266}267268impl<T: WeightInfo> MarginalWeightInfo for T {}269270#[frame_support::pallet]271pub mod pallet {272	use super::*;273	use frame_support::{dispatch::PostDispatchInfo, pallet_prelude::*};274	use system::pallet_prelude::*;275276	/// The current storage version.277	const STORAGE_VERSION: StorageVersion = StorageVersion::new(0);278279    #[pallet::pallet]280	#[pallet::generate_store(pub(super) trait Store)]281	#[pallet::storage_version(STORAGE_VERSION)]282	pub struct Pallet<T>(_);283284	#[pallet::config]285	pub trait Config: frame_system::Config {286        type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;287288        /// The aggregated origin which the dispatch will take.289		type Origin: OriginTrait<PalletsOrigin = Self::PalletsOrigin>290            + From<Self::PalletsOrigin>291            + IsType<<Self as system::Config>::Origin>292			+ Clone;293294        /// The caller origin, overarching type of all pallets origins.295        type PalletsOrigin: From<system::RawOrigin<Self::AccountId>>296            + Codec297            + Clone298            + Eq299            + TypeInfo300            + MaxEncodedLen;301302        /// The aggregated call type.303        type Call: Parameter304            + Dispatchable<305                Origin = <Self as Config>::Origin,306                PostInfo = PostDispatchInfo,307            > + GetDispatchInfo308            + From<system::Call<Self>>;309310        /// The maximum weight that may be scheduled per block for any dispatchables.311        #[pallet::constant]312        type MaximumWeight: Get<Weight>;313314        /// Required origin to schedule or cancel calls.315        type ScheduleOrigin: EnsureOrigin<<Self as system::Config>::Origin>;316317        /// Compare the privileges of origins.318        ///319        /// This will be used when canceling a task, to ensure that the origin that tries320        /// to cancel has greater or equal privileges as the origin that created the scheduled task.321        ///322        /// For simplicity the [`EqualPrivilegeOnly`](frame_support::traits::EqualPrivilegeOnly) can323        /// be used. This will only check if two given origins are equal.324        type OriginPrivilegeCmp: PrivilegeCmp<Self::PalletsOrigin>;325326        /// The maximum number of scheduled calls in the queue for a single block.327        #[pallet::constant]328        type MaxScheduledPerBlock: Get<u32>;329330        /// Weight information for extrinsics in this pallet.331        type WeightInfo: WeightInfo;332333        /// The preimage provider with which we look up call hashes to get the call.334		type Preimages: SchedulerPreimages<Self>;335    }336337    #[pallet::storage]338	pub type IncompleteSince<T: Config> = StorageValue<_, T::BlockNumber>;339340    /// Items to be executed, indexed by the block number that they should be executed on.341	#[pallet::storage]342	pub type Agenda<T: Config> = StorageMap<343		_,344		Twox64Concat,345		T::BlockNumber,346		BoundedVec<Option<ScheduledOf<T>>, T::MaxScheduledPerBlock>,347		ValueQuery,348	>;349350    /// Lookup from a name to the block number and index of the task.351	#[pallet::storage]352	pub(crate) type Lookup<T: Config> =353		StorageMap<_, Twox64Concat, TaskName, TaskAddress<T::BlockNumber>>;354355    /// Events type.356	#[pallet::event]357	#[pallet::generate_deposit(pub(super) fn deposit_event)]358	pub enum Event<T: Config> {359		/// Scheduled some task.360		Scheduled { when: T::BlockNumber, index: u32 },361		/// Canceled some task.362		Canceled { when: T::BlockNumber, index: u32 },363		/// Dispatched some task.364		Dispatched {365			task: TaskAddress<T::BlockNumber>,366			id: Option<[u8; 32]>,367			result: DispatchResult,368		},369		/// The call for the provided hash was not found so the task has been aborted.370		CallUnavailable { task: TaskAddress<T::BlockNumber>, id: Option<[u8; 32]> },371		/// The given task was unable to be renewed since the agenda is full at that block.372		PeriodicFailed { task: TaskAddress<T::BlockNumber>, id: Option<[u8; 32]> },373		/// The given task can never be executed since it is overweight.374		PermanentlyOverweight { task: TaskAddress<T::BlockNumber>, id: Option<[u8; 32]> },375	}376377    #[pallet::error]378	pub enum Error<T> {379		/// Failed to schedule a call380		FailedToSchedule,381        /// There is no place for a new task in the agenda382        AgendaIsExhausted,383		/// Scheduled call is corrupted384		ScheduledCallCorrupted,385		/// Scheduled call preimage is not found386		PreimageNotFound,387		/// Scheduled call is too big388		TooBigScheduledCall,389		/// Cannot find the scheduled call.390		NotFound,391		/// Given target block number is in the past.392		TargetBlockNumberInPast,393		/// Reschedule failed because it does not change scheduled time.394		RescheduleNoChange,395		/// Attempt to use a non-named function on a named task.396		Named,397	}398399    #[pallet::hooks]400	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {401		/// Execute the scheduled calls402		fn on_initialize(now: T::BlockNumber) -> Weight {403			let mut weight_counter =404				WeightCounter { used: Weight::zero(), limit: T::MaximumWeight::get() };405			Self::service_agendas(&mut weight_counter, now, u32::max_value());406			weight_counter.used407		}408	}409410    #[pallet::call]411	impl<T: Config> Pallet<T> {412        /// Anonymously schedule a task.413		#[pallet::weight(<T as Config>::WeightInfo::schedule(T::MaxScheduledPerBlock::get()))]414		pub fn schedule(415			origin: OriginFor<T>,416			when: T::BlockNumber,417			maybe_periodic: Option<schedule::Period<T::BlockNumber>>,418			priority: schedule::Priority,419			call: Box<<T as Config>::Call>,420		) -> DispatchResult {421			T::ScheduleOrigin::ensure_origin(origin.clone())?;422			let origin = <T as Config>::Origin::from(origin);423			Self::do_schedule(424				DispatchTime::At(when),425				maybe_periodic,426				priority,427				origin.caller().clone(),428				<ScheduledCall<T>>::new(*call)?,429			)?;430			Ok(())431		}432433		/// Cancel an anonymously scheduled task.434		#[pallet::weight(<T as Config>::WeightInfo::cancel(T::MaxScheduledPerBlock::get()))]435		pub fn cancel(origin: OriginFor<T>, when: T::BlockNumber, index: u32) -> DispatchResult {436			T::ScheduleOrigin::ensure_origin(origin.clone())?;437			let origin = <T as Config>::Origin::from(origin);438			Self::do_cancel(Some(origin.caller().clone()), (when, index))?;439			Ok(())440		}441442		/// Schedule a named task.443		#[pallet::weight(<T as Config>::WeightInfo::schedule_named(T::MaxScheduledPerBlock::get()))]444		pub fn schedule_named(445			origin: OriginFor<T>,446			id: TaskName,447			when: T::BlockNumber,448			maybe_periodic: Option<schedule::Period<T::BlockNumber>>,449			priority: schedule::Priority,450			call: Box<<T as Config>::Call>,451		) -> DispatchResult {452			T::ScheduleOrigin::ensure_origin(origin.clone())?;453			let origin = <T as Config>::Origin::from(origin);454			Self::do_schedule_named(455				id,456				DispatchTime::At(when),457				maybe_periodic,458				priority,459				origin.caller().clone(),460				<ScheduledCall<T>>::new(*call)?,461			)?;462			Ok(())463		}464465		/// Cancel a named scheduled task.466		#[pallet::weight(<T as Config>::WeightInfo::cancel_named(T::MaxScheduledPerBlock::get()))]467		pub fn cancel_named(origin: OriginFor<T>, id: TaskName) -> DispatchResult {468			T::ScheduleOrigin::ensure_origin(origin.clone())?;469			let origin = <T as Config>::Origin::from(origin);470			Self::do_cancel_named(Some(origin.caller().clone()), id)?;471			Ok(())472		}473474		/// Anonymously schedule a task after a delay.475		///476		/// # <weight>477		/// Same as [`schedule`].478		/// # </weight>479		#[pallet::weight(<T as Config>::WeightInfo::schedule(T::MaxScheduledPerBlock::get()))]480		pub fn schedule_after(481			origin: OriginFor<T>,482			after: T::BlockNumber,483			maybe_periodic: Option<schedule::Period<T::BlockNumber>>,484			priority: schedule::Priority,485			call: Box<<T as Config>::Call>,486		) -> DispatchResult {487			T::ScheduleOrigin::ensure_origin(origin.clone())?;488			let origin = <T as Config>::Origin::from(origin);489			Self::do_schedule(490				DispatchTime::After(after),491				maybe_periodic,492				priority,493				origin.caller().clone(),494				<ScheduledCall<T>>::new(*call)?,495			)?;496			Ok(())497		}498499		/// Schedule a named task after a delay.500		///501		/// # <weight>502		/// Same as [`schedule_named`](Self::schedule_named).503		/// # </weight>504		#[pallet::weight(<T as Config>::WeightInfo::schedule_named(T::MaxScheduledPerBlock::get()))]505		pub fn schedule_named_after(506			origin: OriginFor<T>,507			id: TaskName,508			after: T::BlockNumber,509			maybe_periodic: Option<schedule::Period<T::BlockNumber>>,510			priority: schedule::Priority,511			call: Box<<T as Config>::Call>,512		) -> DispatchResult {513			T::ScheduleOrigin::ensure_origin(origin.clone())?;514			let origin = <T as Config>::Origin::from(origin);515			Self::do_schedule_named(516				id,517				DispatchTime::After(after),518				maybe_periodic,519				priority,520				origin.caller().clone(),521				<ScheduledCall<T>>::new(*call)?,522			)?;523			Ok(())524		}525    }526}527528impl<T: Config> Pallet<T> {529    fn resolve_time(when: DispatchTime<T::BlockNumber>) -> Result<T::BlockNumber, DispatchError> {530		let now = frame_system::Pallet::<T>::block_number();531532		let when = match when {533			DispatchTime::At(x) => x,534			// The current block has already completed it's scheduled tasks, so535			// Schedule the task at lest one block after this current block.536			DispatchTime::After(x) => now.saturating_add(x).saturating_add(One::one()),537		};538539		if when <= now {540			return Err(Error::<T>::TargetBlockNumberInPast.into())541		}542543		Ok(when)544	}545546    fn place_task(547		when: T::BlockNumber,548		what: ScheduledOf<T>,549	) -> Result<TaskAddress<T::BlockNumber>, (DispatchError, ScheduledOf<T>)> {550		let maybe_name = what.maybe_id;551		let index = Self::push_to_agenda(when, what)?;552		let address = (when, index);553		if let Some(name) = maybe_name {554			Lookup::<T>::insert(name, address)555		}556		Self::deposit_event(Event::Scheduled { when: address.0, index: address.1 });557		Ok(address)558	}559560    fn push_to_agenda(561		when: T::BlockNumber,562		what: ScheduledOf<T>,563	) -> Result<u32, (DispatchError, ScheduledOf<T>)> {564		let mut agenda = Agenda::<T>::get(when);565		let index = if (agenda.len() as u32) < T::MaxScheduledPerBlock::get() {566			// will always succeed due to the above check.567			let _ = agenda.try_push(Some(what));568			agenda.len() as u32 - 1569		} else {570			if let Some(hole_index) = agenda.iter().position(|i| i.is_none()) {571				agenda[hole_index] = Some(what);572				hole_index as u32573			} else {574				return Err((<Error<T>>::AgendaIsExhausted.into(), what))575			}576		};577		Agenda::<T>::insert(when, agenda);578		Ok(index)579	}580581    fn do_schedule(582		when: DispatchTime<T::BlockNumber>,583		maybe_periodic: Option<schedule::Period<T::BlockNumber>>,584		priority: schedule::Priority,585		origin: T::PalletsOrigin,586		call: ScheduledCall<T>,587	) -> Result<TaskAddress<T::BlockNumber>, DispatchError> {588		let when = Self::resolve_time(when)?;589590		// sanitize maybe_periodic591		let maybe_periodic = maybe_periodic592			.filter(|p| p.1 > 1 && !p.0.is_zero())593			// Remove one from the number of repetitions since we will schedule one now.594			.map(|(p, c)| (p, c - 1));595		let task = Scheduled {596			maybe_id: None,597			priority,598			call,599			maybe_periodic,600			origin,601			_phantom: PhantomData,602		};603		Self::place_task(when, task).map_err(|x| x.0)604	}605606    fn do_cancel(607		origin: Option<T::PalletsOrigin>,608		(when, index): TaskAddress<T::BlockNumber>,609	) -> Result<(), DispatchError> {610		let scheduled = Agenda::<T>::try_mutate(when, |agenda| {611			agenda.get_mut(index as usize).map_or(612				Ok(None),613				|s| -> Result<Option<Scheduled<_, _, _, _, _>>, DispatchError> {614					if let (Some(ref o), Some(ref s)) = (origin, s.borrow()) {615						if matches!(616							T::OriginPrivilegeCmp::cmp_privilege(o, &s.origin),617							Some(Ordering::Less) | None618						) {619							return Err(BadOrigin.into())620						}621					};622					Ok(s.take())623				},624			)625		})?;626		if let Some(s) = scheduled {627            T::Preimages::drop(&s.call);628629			if let Some(id) = s.maybe_id {630				Lookup::<T>::remove(id);631			}632			Self::deposit_event(Event::Canceled { when, index });633			Ok(())634		} else {635			return Err(Error::<T>::NotFound.into())636		}637	}638639    fn do_schedule_named(640		id: TaskName,641		when: DispatchTime<T::BlockNumber>,642		maybe_periodic: Option<schedule::Period<T::BlockNumber>>,643		priority: schedule::Priority,644		origin: T::PalletsOrigin,645		call: ScheduledCall<T>,646	) -> Result<TaskAddress<T::BlockNumber>, DispatchError> {647		// ensure id it is unique648		if Lookup::<T>::contains_key(&id) {649			return Err(Error::<T>::FailedToSchedule.into())650		}651652		let when = Self::resolve_time(when)?;653654		// sanitize maybe_periodic655		let maybe_periodic = maybe_periodic656			.filter(|p| p.1 > 1 && !p.0.is_zero())657			// Remove one from the number of repetitions since we will schedule one now.658			.map(|(p, c)| (p, c - 1));659660		let task = Scheduled {661			maybe_id: Some(id),662			priority,663			call,664			maybe_periodic,665			origin,666			_phantom: Default::default(),667		};668		Self::place_task(when, task).map_err(|x| x.0)669	}670671    fn do_cancel_named(origin: Option<T::PalletsOrigin>, id: TaskName) -> DispatchResult {672		Lookup::<T>::try_mutate_exists(id, |lookup| -> DispatchResult {673			if let Some((when, index)) = lookup.take() {674				let i = index as usize;675				Agenda::<T>::try_mutate(when, |agenda| -> DispatchResult {676					if let Some(s) = agenda.get_mut(i) {677						if let (Some(ref o), Some(ref s)) = (origin, s.borrow()) {678							if matches!(679								T::OriginPrivilegeCmp::cmp_privilege(o, &s.origin),680								Some(Ordering::Less) | None681							) {682								return Err(BadOrigin.into())683							}684							T::Preimages::drop(&s.call);685						}686						*s = None;687					}688					Ok(())689				})?;690				Self::deposit_event(Event::Canceled { when, index });691				Ok(())692			} else {693				return Err(Error::<T>::NotFound.into())694			}695		})696	}697}698699enum ServiceTaskError {700	/// Could not be executed due to missing preimage.701	Unavailable,702	/// Could not be executed due to weight limitations.703	Overweight,704}705use ServiceTaskError::*;706707impl<T: Config> Pallet<T> {708	/// Service up to `max` agendas queue starting from earliest incompletely executed agenda.709	fn service_agendas(weight: &mut WeightCounter, now: T::BlockNumber, max: u32) {710		if !weight.check_accrue(T::WeightInfo::service_agendas_base()) {711			return712		}713714		let mut incomplete_since = now + One::one();715		let mut when = IncompleteSince::<T>::take().unwrap_or(now);716		let mut executed = 0;717718		let max_items = T::MaxScheduledPerBlock::get();719		let mut count_down = max;720		let service_agenda_base_weight = T::WeightInfo::service_agenda_base(max_items);721		while count_down > 0 && when <= now && weight.can_accrue(service_agenda_base_weight) {722			if !Self::service_agenda(weight, &mut executed, now, when, u32::max_value()) {723				incomplete_since = incomplete_since.min(when);724			}725			when.saturating_inc();726			count_down.saturating_dec();727		}728		incomplete_since = incomplete_since.min(when);729		if incomplete_since <= now {730			IncompleteSince::<T>::put(incomplete_since);731		}732	}733734	/// Returns `true` if the agenda was fully completed, `false` if it should be revisited at a735	/// later block.736	fn service_agenda(737		weight: &mut WeightCounter,738		executed: &mut u32,739		now: T::BlockNumber,740		when: T::BlockNumber,741		max: u32,742	) -> bool {743		let mut agenda = Agenda::<T>::get(when);744		let mut ordered = agenda745			.iter()746			.enumerate()747			.filter_map(|(index, maybe_item)| {748				maybe_item.as_ref().map(|item| (index as u32, item.priority))749			})750			.collect::<Vec<_>>();751		ordered.sort_by_key(|k| k.1);752		let within_limit =753			weight.check_accrue(T::WeightInfo::service_agenda_base(ordered.len() as u32));754		debug_assert!(within_limit, "weight limit should have been checked in advance");755756		// Items which we know can be executed and have postponed for execution in a later block.757		let mut postponed = (ordered.len() as u32).saturating_sub(max);758		// Items which we don't know can ever be executed.759		let mut dropped = 0;760761		for (agenda_index, _) in ordered.into_iter().take(max as usize) {762			let task = match agenda[agenda_index as usize].take() {763				None => continue,764				Some(t) => t,765			};766			let base_weight = T::WeightInfo::service_task(767				task.call.lookup_len().map(|x| x as usize),768				task.maybe_id.is_some(),769				task.maybe_periodic.is_some(),770			);771			if !weight.can_accrue(base_weight) {772				postponed += 1;773				break774			}775			let result = Self::service_task(weight, now, when, agenda_index, *executed == 0, task);776			agenda[agenda_index as usize] = match result {777				Err((Unavailable, slot)) => {778					dropped += 1;779					slot780				},781				Err((Overweight, slot)) => {782					postponed += 1;783					slot784				},785				Ok(()) => {786					*executed += 1;787					None788				},789			};790		}791		if postponed > 0 || dropped > 0 {792			Agenda::<T>::insert(when, agenda);793		} else {794			Agenda::<T>::remove(when);795		}796		postponed == 0797	}798799	/// Service (i.e. execute) the given task, being careful not to overflow the `weight` counter.800	///801	/// This involves:802	/// - removing and potentially replacing the `Lookup` entry for the task.803	/// - realizing the task's call which can include a preimage lookup.804	/// - Rescheduling the task for execution in a later agenda if periodic.805	fn service_task(806		weight: &mut WeightCounter,807		now: T::BlockNumber,808		when: T::BlockNumber,809		agenda_index: u32,810		is_first: bool,811		mut task: ScheduledOf<T>,812	) -> Result<(), (ServiceTaskError, Option<ScheduledOf<T>>)> {813		if let Some(ref id) = task.maybe_id {814			Lookup::<T>::remove(id);815		}816817		let (call, lookup_len) = match T::Preimages::peek(&task.call) {818			Ok(c) => c,819			Err(_) => return Err((Unavailable, Some(task))),820		};821822		weight.check_accrue(T::WeightInfo::service_task(823			lookup_len.map(|x| x as usize),824			task.maybe_id.is_some(),825			task.maybe_periodic.is_some(),826		));827828		match Self::execute_dispatch(weight, task.origin.clone(), call) {829			Err(Unavailable) => {830				debug_assert!(false, "Checked to exist with `peek`");831				Self::deposit_event(Event::CallUnavailable {832					task: (when, agenda_index),833					id: task.maybe_id,834				});835				Err((Unavailable, Some(task)))836			},837			Err(Overweight) if is_first => {838				T::Preimages::drop(&task.call);839				Self::deposit_event(Event::PermanentlyOverweight {840					task: (when, agenda_index),841					id: task.maybe_id,842				});843				Err((Unavailable, Some(task)))844			},845			Err(Overweight) => Err((Overweight, Some(task))),846			Ok(result) => {847				Self::deposit_event(Event::Dispatched {848					task: (when, agenda_index),849					id: task.maybe_id,850					result,851				});852				if let &Some((period, count)) = &task.maybe_periodic {853					if count > 1 {854						task.maybe_periodic = Some((period, count - 1));855					} else {856						task.maybe_periodic = None;857					}858					let wake = now.saturating_add(period);859					match Self::place_task(wake, task) {860						Ok(_) => {},861						Err((_, task)) => {862							// TODO: Leave task in storage somewhere for it to be rescheduled863							// manually.864							T::Preimages::drop(&task.call);865							Self::deposit_event(Event::PeriodicFailed {866								task: (when, agenda_index),867								id: task.maybe_id,868							});869						},870					}871				} else {872					T::Preimages::drop(&task.call);873				}874				Ok(())875			},876		}877	}878879	/// Make a dispatch to the given `call` from the given `origin`, ensuring that the `weight`880	/// counter does not exceed its limit and that it is counted accurately (e.g. accounted using881	/// post info if available).882	///883	/// NOTE: Only the weight for this function will be counted (origin lookup, dispatch and the884	/// call itself).885	fn execute_dispatch(886		weight: &mut WeightCounter,887		origin: T::PalletsOrigin,888		call: <T as Config>::Call,889	) -> Result<DispatchResult, ServiceTaskError> {890		let dispatch_origin: <T as Config>::Origin = origin.into();891		let base_weight = match dispatch_origin.clone().as_signed() {892			Some(_) => T::WeightInfo::execute_dispatch_signed(),893			_ => T::WeightInfo::execute_dispatch_unsigned(),894		};895		let call_weight = call.get_dispatch_info().weight;896		// We only allow a scheduled call if it cannot push the weight past the limit.897		let max_weight = base_weight.saturating_add(call_weight);898899		if !weight.can_accrue(max_weight) {900			return Err(Overweight)901		}902903		let (maybe_actual_call_weight, result) = match call.dispatch(dispatch_origin) {904			Ok(post_info) => (post_info.actual_weight, Ok(())),905			Err(error_and_info) =>906				(error_and_info.post_info.actual_weight, Err(error_and_info.error)),907		};908		let call_weight = maybe_actual_call_weight.unwrap_or(call_weight);909		weight.check_accrue(base_weight);910		weight.check_accrue(call_weight);911		Ok(result)912	}913}