120 lines
5.0 KiB
Go
120 lines
5.0 KiB
Go
package keeper
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import (
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sdk "github.com/cosmos/cosmos-sdk/types"
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"github.com/cosmos/cosmos-sdk/x/distribution/types"
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)
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// initialize starting info for a new delegation
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func (k Keeper) initializeDelegation(ctx sdk.Context, val sdk.ValAddress, del sdk.AccAddress) {
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// period has already been incremented - we want to store the period ended by this delegation action
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previousPeriod := k.GetValidatorCurrentRewards(ctx, val).Period - 1
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// increment reference count for the period we're going to track
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k.incrementReferenceCount(ctx, val, previousPeriod)
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validator := k.stakingKeeper.Validator(ctx, val)
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delegation := k.stakingKeeper.Delegation(ctx, del, val)
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// calculate delegation stake in tokens
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// we don't store directly, so multiply delegation shares * (tokens per share)
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// note: necessary to truncate so we don't allow withdrawing more rewards than owed
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stake := delegation.GetShares().MulTruncate(validator.GetDelegatorShareExRate())
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k.SetDelegatorStartingInfo(ctx, val, del, types.NewDelegatorStartingInfo(previousPeriod, stake, uint64(ctx.BlockHeight())))
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}
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// calculate the rewards accrued by a delegation between two periods
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func (k Keeper) calculateDelegationRewardsBetween(ctx sdk.Context, val sdk.Validator,
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startingPeriod, endingPeriod uint64, stake sdk.Dec) (rewards sdk.DecCoins) {
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// sanity check
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if startingPeriod > endingPeriod {
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panic("startingPeriod cannot be greater than endingPeriod")
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}
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// sanity check
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if stake.LT(sdk.ZeroDec()) {
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panic("stake should not be negative")
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}
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// return staking * (ending - starting)
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starting := k.GetValidatorHistoricalRewards(ctx, val.GetOperator(), startingPeriod)
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ending := k.GetValidatorHistoricalRewards(ctx, val.GetOperator(), endingPeriod)
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difference := ending.CumulativeRewardRatio.Sub(starting.CumulativeRewardRatio)
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if difference.IsAnyNegative() {
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panic("negative rewards should not be possible")
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}
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// note: necessary to truncate so we don't allow withdrawing more rewards than owed
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rewards = difference.MulDecTruncate(stake)
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return
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}
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// calculate the total rewards accrued by a delegation
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func (k Keeper) calculateDelegationRewards(ctx sdk.Context, val sdk.Validator, del sdk.Delegation, endingPeriod uint64) (rewards sdk.DecCoins) {
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// fetch starting info for delegation
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startingInfo := k.GetDelegatorStartingInfo(ctx, del.GetValidatorAddr(), del.GetDelegatorAddr())
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startingPeriod := startingInfo.PreviousPeriod
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stake := startingInfo.Stake
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// iterate through slashes and withdraw with calculated staking for sub-intervals
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// these offsets are dependent on *when* slashes happen - namely, in BeginBlock, after rewards are allocated...
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// ... so we don't reduce stake for slashes which happened in the *first* block, because the delegation wouldn't have existed
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startingHeight := startingInfo.Height + 1
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// ... or slashes which happened in *this* block, since they would have happened after reward allocation
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endingHeight := uint64(ctx.BlockHeight()) - 1
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if endingHeight >= startingHeight {
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k.IterateValidatorSlashEventsBetween(ctx, del.GetValidatorAddr(), startingHeight, endingHeight,
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func(height uint64, event types.ValidatorSlashEvent) (stop bool) {
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endingPeriod := event.ValidatorPeriod
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rewards = rewards.Add(k.calculateDelegationRewardsBetween(ctx, val, startingPeriod, endingPeriod, stake))
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// note: necessary to truncate so we don't allow withdrawing more rewards than owed
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stake = stake.MulTruncate(sdk.OneDec().Sub(event.Fraction))
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startingPeriod = endingPeriod
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return false
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},
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)
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}
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// calculate rewards for final period
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rewards = rewards.Add(k.calculateDelegationRewardsBetween(ctx, val, startingPeriod, endingPeriod, stake))
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return
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}
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func (k Keeper) withdrawDelegationRewards(ctx sdk.Context, val sdk.Validator, del sdk.Delegation) sdk.Error {
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// check existence of delegator starting info
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if !k.HasDelegatorStartingInfo(ctx, del.GetValidatorAddr(), del.GetDelegatorAddr()) {
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return types.ErrNoDelegationDistInfo(k.codespace)
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}
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// end current period and calculate rewards
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endingPeriod := k.incrementValidatorPeriod(ctx, val)
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rewards := k.calculateDelegationRewards(ctx, val, del, endingPeriod)
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// decrement reference count of starting period
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startingInfo := k.GetDelegatorStartingInfo(ctx, del.GetValidatorAddr(), del.GetDelegatorAddr())
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startingPeriod := startingInfo.PreviousPeriod
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k.decrementReferenceCount(ctx, del.GetValidatorAddr(), startingPeriod)
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// truncate coins, return remainder to community pool
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coins, remainder := rewards.TruncateDecimal()
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outstanding := k.GetOutstandingRewards(ctx)
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k.SetOutstandingRewards(ctx, outstanding.Sub(rewards))
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feePool := k.GetFeePool(ctx)
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feePool.CommunityPool = feePool.CommunityPool.Add(remainder)
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k.SetFeePool(ctx, feePool)
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// add coins to user account
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withdrawAddr := k.GetDelegatorWithdrawAddr(ctx, del.GetDelegatorAddr())
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if _, _, err := k.bankKeeper.AddCoins(ctx, withdrawAddr, coins); err != nil {
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return err
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}
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// remove delegator starting info
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k.DeleteDelegatorStartingInfo(ctx, del.GetValidatorAddr(), del.GetDelegatorAddr())
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return nil
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}
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