108 lines
4.0 KiB
Go
108 lines
4.0 KiB
Go
package feegrant
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import (
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"time"
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sdk "github.com/cosmos/cosmos-sdk/types"
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sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
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)
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var _ FeeAllowanceI = (*PeriodicAllowance)(nil)
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// Accept can use fee payment requested as well as timestamp of the current block
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// to determine whether or not to process this. This is checked in
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// Keeper.UseGrantedFees and the return values should match how it is handled there.
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//
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// If it returns an error, the fee payment is rejected, otherwise it is accepted.
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// The FeeAllowance implementation is expected to update it's internal state
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// and will be saved again after an acceptance.
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//
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// If remove is true (regardless of the error), the FeeAllowance will be deleted from storage
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// (eg. when it is used up). (See call to RevokeAllowance in Keeper.UseGrantedFees)
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func (a *PeriodicAllowance) Accept(ctx sdk.Context, fee sdk.Coins, _ []sdk.Msg) (bool, error) {
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blockTime := ctx.BlockTime()
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if a.Basic.Expiration != nil && blockTime.After(*a.Basic.Expiration) {
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return true, sdkerrors.Wrap(ErrFeeLimitExpired, "absolute limit")
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}
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a.tryResetPeriod(blockTime)
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// deduct from both the current period and the max amount
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var isNeg bool
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a.PeriodCanSpend, isNeg = a.PeriodCanSpend.SafeSub(fee)
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if isNeg {
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return false, sdkerrors.Wrap(ErrFeeLimitExceeded, "period limit")
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}
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if a.Basic.SpendLimit != nil {
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a.Basic.SpendLimit, isNeg = a.Basic.SpendLimit.SafeSub(fee)
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if isNeg {
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return false, sdkerrors.Wrap(ErrFeeLimitExceeded, "absolute limit")
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}
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return a.Basic.SpendLimit.IsZero(), nil
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}
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return false, nil
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}
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// tryResetPeriod will check if the PeriodReset has been hit. If not, it is a no-op.
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// If we hit the reset period, it will top up the PeriodCanSpend amount to
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// min(PeriodSpendLimit, Basic.SpendLimit) so it is never more than the maximum allowed.
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// It will also update the PeriodReset. If we are within one Period, it will update from the
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// last PeriodReset (eg. if you always do one tx per day, it will always reset the same time)
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// If we are more then one period out (eg. no activity in a week), reset is one Period from the execution of this method
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func (a *PeriodicAllowance) tryResetPeriod(blockTime time.Time) {
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if blockTime.Before(a.PeriodReset) {
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return
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}
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// set PeriodCanSpend to the lesser of Basic.SpendLimit and PeriodSpendLimit
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if _, isNeg := a.Basic.SpendLimit.SafeSub(a.PeriodSpendLimit); isNeg && !a.Basic.SpendLimit.Empty() {
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a.PeriodCanSpend = a.Basic.SpendLimit
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} else {
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a.PeriodCanSpend = a.PeriodSpendLimit
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}
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// If we are within the period, step from expiration (eg. if you always do one tx per day, it will always reset the same time)
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// If we are more then one period out (eg. no activity in a week), reset is one period from this time
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a.PeriodReset = a.PeriodReset.Add(a.Period)
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if blockTime.After(a.PeriodReset) {
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a.PeriodReset = blockTime.Add(a.Period)
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}
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}
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// ValidateBasic implements FeeAllowance and enforces basic sanity checks
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func (a PeriodicAllowance) ValidateBasic() error {
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if err := a.Basic.ValidateBasic(); err != nil {
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return err
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}
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if !a.PeriodSpendLimit.IsValid() {
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return sdkerrors.Wrapf(sdkerrors.ErrInvalidCoins, "spend amount is invalid: %s", a.PeriodSpendLimit)
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}
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if !a.PeriodSpendLimit.IsAllPositive() {
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return sdkerrors.Wrap(sdkerrors.ErrInvalidCoins, "spend limit must be positive")
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}
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if !a.PeriodCanSpend.IsValid() {
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return sdkerrors.Wrapf(sdkerrors.ErrInvalidCoins, "can spend amount is invalid: %s", a.PeriodCanSpend)
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}
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// We allow 0 for CanSpend
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if a.PeriodCanSpend.IsAnyNegative() {
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return sdkerrors.Wrap(sdkerrors.ErrInvalidCoins, "can spend must not be negative")
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}
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// ensure PeriodSpendLimit can be subtracted from total (same coin types)
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if a.Basic.SpendLimit != nil && !a.PeriodSpendLimit.DenomsSubsetOf(a.Basic.SpendLimit) {
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return sdkerrors.Wrap(sdkerrors.ErrInvalidCoins, "period spend limit has different currency than basic spend limit")
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}
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// check times
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if a.Period.Seconds() < 0 {
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return sdkerrors.Wrap(ErrInvalidDuration, "negative clock step")
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}
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return nil
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}
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