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// Copyright (C) Moondance Labs Ltd.
// This file is part of Tanssi.
// Tanssi is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// Tanssi is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with Tanssi. If not, see <http://www.gnu.org/licenses/>
use {
crate::{
candidate::Candidates,
pools::{self, Pool},
traits::Timer,
AllTargetPool, Candidate, Config, Delegator, Error, Event, HoldReason, Pallet,
PendingOperationKey, PendingOperationQuery, PendingOperationQueryOf, PendingOperations,
Shares, SharesOrStake, Stake, TargetPool,
},
frame_support::{
dispatch::DispatchErrorWithPostInfo,
pallet_prelude::*,
traits::{
fungible::{Mutate, MutateHold},
tokens::{Precision, Preservation},
sp_runtime::traits::{CheckedSub, Zero},
sp_std::vec::Vec,
tp_maths::{ErrAdd, ErrSub},
};
pub struct Calls<T>(PhantomData<T>);
impl<T: Config> Calls<T> {
pub fn rebalance_hold(
candidate: Candidate<T>,
delegator: Delegator<T>,
pool: AllTargetPool,
) -> DispatchResultWithPostInfo {
let (held, stake) = match pool {
AllTargetPool::Joining => {
let held = pools::Joining::<T>::hold(&candidate, &delegator);
let shares = pools::Joining::<T>::shares(&candidate, &delegator);
let stake = pools::Joining::<T>::shares_to_stake(&candidate, shares)?;
pools::Joining::<T>::set_hold(&candidate, &delegator, stake);
(held, stake)
}
AllTargetPool::AutoCompounding => {
let held = pools::AutoCompounding::<T>::hold(&candidate, &delegator);
let shares = pools::AutoCompounding::<T>::shares(&candidate, &delegator);
let stake = pools::AutoCompounding::<T>::shares_to_stake(&candidate, shares)?;
pools::AutoCompounding::<T>::set_hold(&candidate, &delegator, stake);
AllTargetPool::ManualRewards => {
let held = pools::ManualRewards::<T>::hold(&candidate, &delegator);
let shares = pools::ManualRewards::<T>::shares(&candidate, &delegator);
let stake = pools::ManualRewards::<T>::shares_to_stake(&candidate, shares)?;
pools::ManualRewards::<T>::set_hold(&candidate, &delegator, stake);
AllTargetPool::Leaving => {
let held = pools::Leaving::<T>::hold(&candidate, &delegator);
let shares = pools::Leaving::<T>::shares(&candidate, &delegator);
let stake = pools::Leaving::<T>::shares_to_stake(&candidate, shares)?;
pools::Leaving::<T>::set_hold(&candidate, &delegator, stake);
if stake == held {
return Ok(().into());
if let Some(diff) = stake.0.checked_sub(&held.0) {
T::Currency::transfer(
&T::StakingAccount::get(),
&delegator,
diff,
Preservation::Preserve,
)?;
T::Currency::hold(&HoldReason::PooledStake.into(), &delegator, diff)?;
if let Some(diff) = held.0.checked_sub(&stake.0) {
T::Currency::release(
&HoldReason::PooledStake.into(),
Precision::Exact,
// should be unreachable as diff must either be positive or negative
Ok(().into())
pub fn request_delegate(
pool: TargetPool,
stake: T::Balance,
ensure!(!stake.is_zero(), Error::<T>::StakeMustBeNonZero);
// Convert stake into joining shares quantity.
let shares = pools::Joining::<T>::stake_to_shares_or_init(&candidate, Stake(stake))?;
// If the amount was stake and is less than the value of 1 share it will round down to
// 0 share. We avoid doing any work for 0 shares.
ensure!(!shares.0.is_zero(), Error::<T>::StakeMustBeNonZero);
// We create the new joining shares. It returns the actual amount of stake those shares
// represents (due to rounding).
let stake = pools::Joining::<T>::add_shares(&candidate, &delegator, shares)?;
// We hold the funds of the delegator and register its stake into the candidate stake.
T::Currency::hold(&HoldReason::PooledStake.into(), &delegator, stake.0)?;
pools::Joining::<T>::increase_hold(&candidate, &delegator, &stake)?;
Candidates::<T>::add_total_stake(&candidate, &stake)?;
// We create/mutate a request for joining.
let now = T::JoiningRequestTimer::now();
let operation_key = match pool {
TargetPool::AutoCompounding => PendingOperationKey::JoiningAutoCompounding {
candidate: candidate.clone(),
at: now,
TargetPool::ManualRewards => PendingOperationKey::JoiningManualRewards {
// We store/mutate the operation in storage.
let operation = PendingOperations::<T>::get(&delegator, &operation_key);
let operation = operation
.err_add(&shares.0)
.map_err(|_| Error::<T>::MathOverflow)?;
PendingOperations::<T>::set(&delegator, &operation_key, operation);
pools::check_candidate_consistency::<T>(&candidate)?;
Pallet::<T>::deposit_event(Event::<T>::RequestedDelegate {
candidate,
delegator,
pool,
pending: stake.0,
});
pub fn request_undelegate(
amount: SharesOrStake<T::Balance>,
// Converts amount to shares of the correct pool
let shares = match (amount, pool) {
(SharesOrStake::Shares(s), _) => s,
(SharesOrStake::Stake(s), TargetPool::AutoCompounding) => {
pools::AutoCompounding::<T>::stake_to_shares(&candidate, Stake(s))?.0
(SharesOrStake::Stake(s), TargetPool::ManualRewards) => {
pools::ManualRewards::<T>::stake_to_shares(&candidate, Stake(s))?.0
// Any change in the amount of Manual Rewards shares requires to claim manual rewards.
if let TargetPool::ManualRewards = pool {
Self::claim_manual_rewards(&[(candidate.clone(), delegator.clone())])?;
// Destroy shares
let removed_stake = Self::destroy_shares(&candidate, &delegator, pool, Shares(shares))?;
// All this stake no longer contribute to the election of the candidate.
Candidates::<T>::sub_total_stake(&candidate, removed_stake)?;
// We proceed with the leaving, which create Leaving shares and request,
// and release the dust from the convertion to Leaving shares.
let (leaving_stake, dust) = Self::leave_stake(&candidate, &delegator, removed_stake)?;
Pallet::<T>::deposit_event(Event::<T>::RequestedUndelegate {
from: pool,
pending: leaving_stake.0,
released: dust.0,
pub fn execute_pending_operations(
operations: Vec<PendingOperationQueryOf<T>>,
for (index, query) in operations.into_iter().enumerate() {
// We deconstruct the query and find the balance associated with it.
// If it is zero it may not exist or have been executed before, thus
// we simply skip it instead of erroring.
let PendingOperationQuery {
operation,
} = query;
let value = PendingOperations::<T>::get(&delegator, &operation);
if value.is_zero() {
continue;
match &operation {
PendingOperationKey::JoiningAutoCompounding { candidate, at } => {
ensure!(
T::JoiningRequestTimer::is_elapsed(at),
Error::<T>::RequestCannotBeExecuted(index as u16)
);
Self::execute_joining(
candidate.clone(),
delegator.clone(),
TargetPool::AutoCompounding,
Shares(value),
PendingOperationKey::JoiningManualRewards { candidate, at } => {
TargetPool::ManualRewards,
PendingOperationKey::Leaving { candidate, at } => {
T::LeavingRequestTimer::is_elapsed(at),
Self::execute_leaving(candidate.clone(), delegator.clone(), Shares(value))?;
PendingOperations::<T>::remove(&delegator, &operation);
fn execute_joining(
joining_shares: Shares<T::Balance>,
// Convert joining shares into stake.
let stake = pools::Joining::<T>::sub_shares(&candidate, &delegator, joining_shares)?;
// No rewards are distributed to the Joining pools, so there should always
// be enough hold. Thus no need to rebalance.
pools::Joining::<T>::decrease_hold(&candidate, &delegator, &stake)?;
// Convert stake into shares quantity.
let shares = match pool {
TargetPool::AutoCompounding => {
pools::AutoCompounding::<T>::stake_to_shares_or_init(&candidate, stake)?
TargetPool::ManualRewards => {
pools::ManualRewards::<T>::stake_to_shares_or_init(&candidate, stake)?
// If stake doesn't allow to get at least one share we release all the funds.
if shares.0.is_zero() {
stake.0,
Candidates::<T>::sub_total_stake(&candidate, Stake(stake.0))?;
// We create the new shares. It returns the actual amount of stake those shares
let actually_staked = match pool {
let stake =
pools::AutoCompounding::<T>::add_shares(&candidate, &delegator, shares)?;
pools::AutoCompounding::<T>::increase_hold(&candidate, &delegator, &stake)?;
stake
let stake = pools::ManualRewards::<T>::add_shares(&candidate, &delegator, shares)?;
pools::ManualRewards::<T>::increase_hold(&candidate, &delegator, &stake)?;
// We release currency that couldn't be converted to shares due to rounding.
// This thus can reduce slighly the total stake of the candidate.
let release = stake
.0
.err_sub(&actually_staked.0)
.map_err(|_| Error::<T>::MathUnderflow)?;
release,
Candidates::<T>::sub_total_stake(&candidate, Stake(release))?;
// Events
let event = match pool {
TargetPool::AutoCompounding => Event::<T>::StakedAutoCompounding {
delegator: delegator.clone(),
shares: shares.0,
stake: actually_staked.0,
TargetPool::ManualRewards => Event::<T>::StakedManualRewards {
Pallet::<T>::deposit_event(event);
Pallet::<T>::deposit_event(Event::<T>::ExecutedDelegate {
staked: actually_staked.0,
released: release,
fn execute_leaving(
leavinig_shares: Shares<T::Balance>,
// Convert leaving shares into stake.
let stake = pools::Leaving::<T>::sub_shares(&candidate, &delegator, leavinig_shares)?;
// No rewards are distributed to the Leaving pools, so there should always
pools::Leaving::<T>::decrease_hold(&candidate, &delegator, &stake)?;
// We release the funds and consider them unstaked.
Pallet::<T>::deposit_event(Event::<T>::ExecutedUndelegate {
released: stake.0,
pub fn claim_manual_rewards(
pairs: &[(Candidate<T>, Delegator<T>)],
for (candidate, delegator) in pairs {
let Stake(rewards) = pools::ManualRewards::<T>::claim_rewards(candidate, delegator)?;
if rewards.is_zero() {
rewards,
Pallet::<T>::deposit_event(Event::<T>::ClaimedManualRewards {
pub fn update_candidate_position(candidates: &[Candidate<T>]) -> DispatchResultWithPostInfo {
for candidate in candidates {
let stake = Candidates::<T>::total_stake(candidate);
Candidates::<T>::update_total_stake(candidate, stake)?;
pub fn swap_pool(
source_pool: TargetPool,
let old_shares = match (amount, source_pool) {
// As it will either move in or out of the ManualRewards pool, manual rewards
// needs to be claimed.
// Destroy shares from the old pool.
let removed_stake =
Self::destroy_shares(&candidate, &delegator, source_pool, Shares(old_shares))?;
// Convert removed amount to new pool shares.
let new_shares = match source_pool {
pools::ManualRewards::<T>::stake_to_shares_or_init(&candidate, removed_stake)?
pools::AutoCompounding::<T>::stake_to_shares_or_init(&candidate, removed_stake)?
ensure!(!new_shares.0.is_zero(), Error::<T>::SwapResultsInZeroShares);
// We create new shares in the new pool. It returns the actual amount of stake those shares
let actually_staked = match source_pool {
pools::AutoCompounding::<T>::add_shares(&candidate, &delegator, new_shares)?;
pools::ManualRewards::<T>::add_shares(&candidate, &delegator, new_shares)?;
let stake_decrease = removed_stake
.map_err(Error::<T>::from)?;
// The left-over no longer contribute to the election of the candidate.
Candidates::<T>::sub_total_stake(&candidate, Stake(stake_decrease))?;
let (leaving_stake, dust) = if stake_decrease.is_zero() {
(Stake(0u32.into()), Stake(0u32.into()))
} else {
Self::leave_stake(&candidate, &delegator, Stake(stake_decrease))?
Pallet::<T>::deposit_event(Event::<T>::SwappedPool {
source_pool,
source_shares: old_shares,
source_stake: removed_stake.0,
target_shares: new_shares.0,
target_stake: actually_staked.0,
pending_leaving: leaving_stake.0,
/// Destory ManualReward or AutoCompounding shares while performing hold rebalancing if
/// necessary.
fn destroy_shares(
candidate: &Candidate<T>,
delegator: &Delegator<T>,
shares: Shares<T::Balance>,
) -> Result<Stake<T::Balance>, DispatchErrorWithPostInfo> {
match pool {
let stake = pools::AutoCompounding::<T>::shares_to_stake(candidate, shares)?;
if stake.0 > pools::AutoCompounding::<T>::hold(candidate, delegator).0 {
Self::rebalance_hold(
AllTargetPool::AutoCompounding,
// This should be the same `stake` as before.
let stake = pools::AutoCompounding::<T>::sub_shares(candidate, delegator, shares)?;
pools::AutoCompounding::<T>::decrease_hold(candidate, delegator, &stake)?;
Ok(stake)
let stake = pools::ManualRewards::<T>::shares_to_stake(candidate, shares)?;
if stake.0 > pools::ManualRewards::<T>::hold(candidate, delegator).0 {
AllTargetPool::ManualRewards,
let stake = pools::ManualRewards::<T>::sub_shares(candidate, delegator, shares)?;
pools::ManualRewards::<T>::decrease_hold(candidate, delegator, &stake)?;
/// Perform the leaving proceduce with provided stake, which will create
/// Leaving shares and request, and release the rounding dust. It DOES NOT
/// destroy shares in other pools.
/// Returns a tuple of the amount of stake in the leaving pool and the dust
/// that was released.
fn leave_stake(
stake: Stake<T::Balance>,
) -> Result<(Stake<T::Balance>, Stake<T::Balance>), DispatchErrorWithPostInfo> {
// Create leaving shares.
// As with all pools there will be some rounding error, this amount
// should be small enough so that it is safe to directly release it
// in the delegator account.
let leaving_shares = pools::Leaving::<T>::stake_to_shares_or_init(candidate, stake)?;
let leaving_stake = pools::Leaving::<T>::add_shares(candidate, delegator, leaving_shares)?;
pools::Leaving::<T>::increase_hold(candidate, delegator, &leaving_stake)?;
// We create/mutate a request for leaving.
let now = T::LeavingRequestTimer::now();
let operation_key = PendingOperationKey::Leaving {
let operation = PendingOperations::<T>::get(delegator, &operation_key);
.err_add(&leaving_shares.0)
PendingOperations::<T>::set(delegator, &operation_key, operation);
// We release the dust if non-zero.
let dust = stake
.err_sub(&leaving_stake.0)
if !dust.is_zero() {
dust,
Ok((leaving_stake, Stake(dust)))