75 lines
2.4 KiB
Go
75 lines
2.4 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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"github.com/tendermint/tmlibs/rational"
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)
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// Tick - called at the end of every block
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func Tick(ctx sdk.Context, store types.KVStore) (change []*abci.Validator, err error) {
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// retrieve params
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params := loadParams(store)
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gs := loadGlobalState(store)
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height := ctx.BlockHeight()
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// Process Validator Provisions
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// XXX right now just process every 5 blocks, in new SDK make hourly
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if gs.InflationLastTime+5 <= height {
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gs.InflationLastTime = height
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processProvisions(store, gs, params)
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}
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return UpdateValidatorSet(store, gs, params)
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}
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var hrsPerYr = rational.New(8766) // as defined by a julian year of 365.25 days
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// process provisions for an hour period
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func processProvisions(store types.KVStore, gs *GlobalState, params Params) {
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gs.Inflation = nextInflation(gs, params).Round(1000000000)
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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 := gs.Inflation.Mul(rational.New(gs.TotalSupply)).Quo(hrsPerYr).Evaluate()
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gs.BondedPool += provisions
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gs.TotalSupply += provisions
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// XXX XXX XXX XXX XXX XXX XXX XXX XXX
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// XXX Mint them to the hold account
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// XXX XXX XXX XXX XXX XXX XXX XXX XXX
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// save the params
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saveGlobalState(store, gs)
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}
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// get the next inflation rate for the hour
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func nextInflation(gs *GlobalState, params Params) (inflation rational.Rat) {
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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 := rational.One.Sub(gs.bondedRatio().Quo(params.GoalBonded)).Mul(params.InflationRateChange)
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inflationRateChange := inflationRateChangePerYear.Quo(hrsPerYr)
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// increase the new annual inflation for this next cycle
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inflation = gs.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
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}
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