104 lines
2.7 KiB
Go
104 lines
2.7 KiB
Go
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package pow
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import (
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"fmt"
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"strconv"
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sdk "github.com/cosmos/cosmos-sdk/types"
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bank "github.com/cosmos/cosmos-sdk/x/bank"
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)
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// module users must specify coin denomination and reward (constant) per PoW solution
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type PowConfig struct {
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Denomination string
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Reward int64
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}
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func NewPowConfig(denomination string, reward int64) PowConfig {
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return PowConfig{denomination, reward}
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}
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type Keeper struct {
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key sdk.StoreKey
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config PowConfig
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ck bank.CoinKeeper
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}
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func NewKeeper(key sdk.StoreKey, config PowConfig, ck bank.CoinKeeper) Keeper {
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return Keeper{key, config, ck}
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}
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var lastDifficultyKey = []byte("lastDifficultyKey")
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func (pk Keeper) GetLastDifficulty(ctx sdk.Context) (uint64, error) {
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store := ctx.KVStore(pk.key)
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stored := store.Get(lastDifficultyKey)
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if stored == nil {
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// return the default difficulty of 1 if not set
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// this works OK for this module, but a way to initalize the store (a "genesis block" for the module) might be better in general
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return uint64(1), nil
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} else {
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return strconv.ParseUint(string(stored), 0, 64)
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}
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}
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func (pk Keeper) SetLastDifficulty(ctx sdk.Context, diff uint64) {
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store := ctx.KVStore(pk.key)
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store.Set(lastDifficultyKey, []byte(strconv.FormatUint(diff, 16)))
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}
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var countKey = []byte("count")
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func (pk Keeper) GetLastCount(ctx sdk.Context) (uint64, error) {
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store := ctx.KVStore(pk.key)
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stored := store.Get(countKey)
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if stored == nil {
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return uint64(0), nil
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} else {
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return strconv.ParseUint(string(stored), 0, 64)
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}
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}
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func (pk Keeper) SetLastCount(ctx sdk.Context, count uint64) {
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store := ctx.KVStore(pk.key)
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store.Set(countKey, []byte(strconv.FormatUint(count, 16)))
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}
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func (pk Keeper) CheckValid(ctx sdk.Context, difficulty uint64, count uint64) (uint64, uint64, sdk.Error) {
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lastDifficulty, err := pk.GetLastDifficulty(ctx)
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if err != nil {
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return 0, 0, ErrNonexistentDifficulty()
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}
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newDifficulty := lastDifficulty + 1
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lastCount, err := pk.GetLastCount(ctx)
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if err != nil {
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return 0, 0, ErrNonexistentCount()
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}
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newCount := lastCount + 1
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if count != newCount {
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return 0, 0, ErrInvalidCount(fmt.Sprintf("invalid count: was %d, should have been %d", count, newCount))
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}
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if difficulty != newDifficulty {
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return 0, 0, ErrInvalidDifficulty(fmt.Sprintf("invalid difficulty: was %d, should have been %d", difficulty, newDifficulty))
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}
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return newDifficulty, newCount, nil
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}
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func (pk Keeper) ApplyValid(ctx sdk.Context, sender sdk.Address, newDifficulty uint64, newCount uint64) sdk.Error {
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_, ckErr := pk.ck.AddCoins(ctx, sender, []sdk.Coin{sdk.Coin{pk.config.Denomination, pk.config.Reward}})
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if ckErr != nil {
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return ckErr
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}
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pk.SetLastDifficulty(ctx, newDifficulty)
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pk.SetLastCount(ctx, newCount)
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return nil
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}
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