120 lines
3.1 KiB
Go
120 lines
3.1 KiB
Go
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 Config struct {
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Denomination string
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Reward int64
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}
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// genesis info must specify starting difficulty and starting count
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type Genesis struct {
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Difficulty uint64 `json:"difficulty"`
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Count uint64 `json:"count"`
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}
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// POW Keeper
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type Keeper struct {
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key sdk.StoreKey
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config Config
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ck bank.Keeper
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codespace sdk.CodespaceType
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}
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func NewConfig(denomination string, reward int64) Config {
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return Config{denomination, reward}
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}
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func NewKeeper(key sdk.StoreKey, config Config, ck bank.Keeper, codespace sdk.CodespaceType) Keeper {
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return Keeper{key, config, ck, codespace}
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}
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// Init Genessis for the POW module
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func (k Keeper) InitGenesis(ctx sdk.Context, genesis Genesis) error {
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k.SetLastDifficulty(ctx, genesis.Difficulty)
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k.SetLastCount(ctx, genesis.Count)
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return nil
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}
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var lastDifficultyKey = []byte("lastDifficultyKey")
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// get the last mining difficulty
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func (k Keeper) GetLastDifficulty(ctx sdk.Context) (uint64, error) {
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store := ctx.KVStore(k.key)
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stored := store.Get(lastDifficultyKey)
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if stored == nil {
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panic("no stored difficulty")
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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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// set the last mining difficulty
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func (k Keeper) SetLastDifficulty(ctx sdk.Context, diff uint64) {
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store := ctx.KVStore(k.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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// get the last count
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func (k Keeper) GetLastCount(ctx sdk.Context) (uint64, error) {
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store := ctx.KVStore(k.key)
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stored := store.Get(countKey)
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if stored == nil {
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panic("no stored count")
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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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// set the last count
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func (k Keeper) SetLastCount(ctx sdk.Context, count uint64) {
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store := ctx.KVStore(k.key)
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store.Set(countKey, []byte(strconv.FormatUint(count, 16)))
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}
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// Is the keeper state valid?
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func (k Keeper) CheckValid(ctx sdk.Context, difficulty uint64, count uint64) (uint64, uint64, sdk.Error) {
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lastDifficulty, err := k.GetLastDifficulty(ctx)
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if err != nil {
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return 0, 0, ErrNonexistentDifficulty(k.codespace)
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}
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newDifficulty := lastDifficulty + 1
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lastCount, err := k.GetLastCount(ctx)
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if err != nil {
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return 0, 0, ErrNonexistentCount(k.codespace)
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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(k.codespace, 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(k.codespace, 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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// Add some coins for a POW well done
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func (k Keeper) ApplyValid(ctx sdk.Context, sender sdk.Address, newDifficulty uint64, newCount uint64) sdk.Error {
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_, ckErr := k.ck.AddCoins(ctx, sender, []sdk.Coin{sdk.Coin{k.config.Denomination, k.config.Reward}})
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if ckErr != nil {
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return ckErr
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}
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k.SetLastDifficulty(ctx, newDifficulty)
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k.SetLastCount(ctx, newCount)
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return nil
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}
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