76 lines
2.3 KiB
Go
76 lines
2.3 KiB
Go
package stake
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import (
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sdk "github.com/cosmos/cosmos-sdk/types"
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abci "github.com/tendermint/abci/types"
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)
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const (
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hrsPerYr = 8766 // as defined by a julian year of 365.25 days
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precision = 1000000000
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)
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var hrsPerYrRat = sdk.NewRat(hrsPerYr) // as defined by a julian year of 365.25 days
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// Tick - called at the end of every block
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func (k Keeper) Tick(ctx sdk.Context) (change []abci.Validator) {
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p := k.GetPool(ctx)
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// Process Validator Provisions
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blockTime := ctx.BlockHeader().Time // XXX assuming in seconds, confirm
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if p.InflationLastTime+blockTime >= 3600 {
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p.InflationLastTime = blockTime
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p = k.processProvisions(ctx)
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}
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// save the params
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k.setPool(ctx, p)
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change = k.getAccUpdateValidators(ctx)
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return
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}
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// process provisions for an hour period
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func (k Keeper) processProvisions(ctx sdk.Context) Pool {
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pool := k.GetPool(ctx)
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pool.Inflation = k.nextInflation(ctx)
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// Because the validators hold a relative bonded share (`GlobalStakeShare`), when
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// more bonded tokens are added proportionally to all validators the only term
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// which needs to be updated is the `BondedPool`. So for each previsions cycle:
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provisions := pool.Inflation.Mul(sdk.NewRat(pool.TotalSupply)).Quo(hrsPerYrRat).Evaluate()
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pool.BondedPool += provisions
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pool.TotalSupply += provisions
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return pool
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}
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// get the next inflation rate for the hour
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func (k Keeper) nextInflation(ctx sdk.Context) (inflation sdk.Rat) {
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params := k.GetParams(ctx)
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pool := k.GetPool(ctx)
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// The target annual inflation rate is recalculated for each previsions cycle. The
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// inflation is also subject to a rate change (positive of negative) depending or
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// the distance from the desired ratio (67%). The maximum rate change possible is
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// defined to be 13% per year, however the annual inflation is capped as between
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// 7% and 20%.
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// (1 - bondedRatio/GoalBonded) * InflationRateChange
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inflationRateChangePerYear := sdk.OneRat.Sub(pool.bondedRatio().Quo(params.GoalBonded)).Mul(params.InflationRateChange)
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inflationRateChange := inflationRateChangePerYear.Quo(hrsPerYrRat)
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// increase the new annual inflation for this next cycle
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inflation = pool.Inflation.Add(inflationRateChange)
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if inflation.GT(params.InflationMax) {
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inflation = params.InflationMax
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}
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if inflation.LT(params.InflationMin) {
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inflation = params.InflationMin
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}
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return inflation.Round(precision)
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}
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