cosmos-sdk/x/distribution/types/delegation_info.go

123 lines
3.9 KiB
Go

package types
import (
"fmt"
sdk "github.com/cosmos/cosmos-sdk/types"
)
// distribution info for a delegation - used to determine entitled rewards
type DelegationDistInfo struct {
DelegatorAddr sdk.AccAddress `json:"delegator_addr"`
ValOperatorAddr sdk.ValAddress `json:"val_operator_addr"`
DelPoolWithdrawalHeight int64 `json:"del_pool_withdrawal_height"` // last time this delegation withdrew rewards
}
func NewDelegationDistInfo(delegatorAddr sdk.AccAddress, valOperatorAddr sdk.ValAddress,
currentHeight int64) DelegationDistInfo {
return DelegationDistInfo{
DelegatorAddr: delegatorAddr,
ValOperatorAddr: valOperatorAddr,
DelPoolWithdrawalHeight: currentHeight,
}
}
// Get the calculated accum of this delegator at the provided height
func (di DelegationDistInfo) GetDelAccum(height int64, delegatorShares sdk.Dec) sdk.Dec {
blocks := height - di.DelPoolWithdrawalHeight
accum := delegatorShares.MulInt(sdk.NewInt(blocks))
// defensive check
if accum.IsNegative() {
panic(fmt.Sprintf("negative accum: %v\n"+
"\theight: %v\n"+
"\tdelegation_dist_info: %v\n"+
"\tdelegator_shares: %v\n",
accum.String(), height, di, delegatorShares))
}
return accum
}
// Withdraw rewards from delegator.
// Among many things, it does:
// * updates validator info's total del accum
// * calls vi.TakeFeePoolRewards, which:
// * updates validator info's FeePoolWithdrawalHeight, thus setting accum to 0
// * updates fee pool to latest height and total val accum w/ given totalBonded
// (see comment on TakeFeePoolRewards for more info)
func (di DelegationDistInfo) WithdrawRewards(wc WithdrawContext, vi ValidatorDistInfo,
totalDelShares, delegatorShares sdk.Dec) (
DelegationDistInfo, ValidatorDistInfo, FeePool, DecCoins) {
fp := wc.FeePool
vi = vi.UpdateTotalDelAccum(wc.Height, totalDelShares)
// Break out to prevent a divide by zero.
if vi.DelAccum.Accum.IsZero() {
di.DelPoolWithdrawalHeight = wc.Height
return di, vi, fp, DecCoins{}
}
vi, fp = vi.TakeFeePoolRewards(wc)
accum := di.GetDelAccum(wc.Height, delegatorShares)
di.DelPoolWithdrawalHeight = wc.Height
withdrawalTokens := vi.DelPool.MulDec(accum).QuoDec(vi.DelAccum.Accum)
// Clip withdrawal tokens by pool, due to possible rounding errors.
// This rounding error may be introduced upon multiplication since
// we're clipping decimal digits, and then when we divide by a number ~1 or
// < 1, the error doesn't get "buried", and if << 1 it'll get amplified.
// more: https://github.com/cosmos/cosmos-sdk/issues/2888#issuecomment-441387987
for i, decCoin := range withdrawalTokens {
poolDenomAmount := vi.DelPool.AmountOf(decCoin.Denom)
if decCoin.Amount.GT(poolDenomAmount) {
withdrawalTokens[i] = NewDecCoinFromDec(decCoin.Denom, poolDenomAmount)
}
}
// defensive check for impossible accum ratios
if accum.GT(vi.DelAccum.Accum) {
panic(fmt.Sprintf("accum > vi.DelAccum.Accum:\n"+
"\taccum\t\t\t%v\n"+
"\tvi.DelAccum.Accum\t%v\n",
accum, vi.DelAccum.Accum))
}
remDelPool := vi.DelPool.Minus(withdrawalTokens)
// defensive check
if remDelPool.HasNegative() {
panic(fmt.Sprintf("negative remDelPool: %v\n"+
"\tvi.DelPool\t\t%v\n"+
"\taccum\t\t\t%v\n"+
"\tvi.DelAccum.Accum\t%v\n"+
"\twithdrawalTokens\t%v\n",
remDelPool, vi.DelPool, accum,
vi.DelAccum.Accum, withdrawalTokens))
}
vi.DelPool = remDelPool
vi.DelAccum.Accum = vi.DelAccum.Accum.Sub(accum)
return di, vi, fp, withdrawalTokens
}
// get the delegators rewards at this current state,
func (di DelegationDistInfo) CurrentRewards(wc WithdrawContext, vi ValidatorDistInfo,
totalDelShares, delegatorShares sdk.Dec) DecCoins {
totalDelAccum := vi.GetTotalDelAccum(wc.Height, totalDelShares)
if vi.DelAccum.Accum.IsZero() {
return DecCoins{}
}
rewards := vi.CurrentPoolRewards(wc)
accum := di.GetDelAccum(wc.Height, delegatorShares)
tokens := rewards.MulDec(accum).QuoDec(totalDelAccum)
return tokens
}