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165 lines
3.7 KiB
165 lines
3.7 KiB
package kvstore
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import (
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"bytes"
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"encoding/binary"
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"encoding/json"
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"fmt"
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dbm "github.com/tendermint/tm-db"
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"github.com/tendermint/tendermint/abci/example/code"
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"github.com/tendermint/tendermint/abci/types"
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"github.com/tendermint/tendermint/libs/kv"
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"github.com/tendermint/tendermint/version"
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)
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var (
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stateKey = []byte("stateKey")
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kvPairPrefixKey = []byte("kvPairKey:")
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ProtocolVersion version.Protocol = 0x1
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)
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type State struct {
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db dbm.DB
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Size int64 `json:"size"`
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Height int64 `json:"height"`
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AppHash []byte `json:"app_hash"`
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}
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func loadState(db dbm.DB) State {
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var state State
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state.db = db
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stateBytes, err := db.Get(stateKey)
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if err != nil {
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panic(err)
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}
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if len(stateBytes) == 0 {
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return state
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}
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err = json.Unmarshal(stateBytes, &state)
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if err != nil {
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panic(err)
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}
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return state
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}
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func saveState(state State) {
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stateBytes, err := json.Marshal(state)
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if err != nil {
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panic(err)
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}
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state.db.Set(stateKey, stateBytes)
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}
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func prefixKey(key []byte) []byte {
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return append(kvPairPrefixKey, key...)
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}
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//---------------------------------------------------
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var _ types.Application = (*Application)(nil)
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type Application struct {
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types.BaseApplication
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state State
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RetainBlocks int64 // blocks to retain after commit (via ResponseCommit.RetainHeight)
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}
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func NewApplication() *Application {
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state := loadState(dbm.NewMemDB())
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return &Application{state: state}
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}
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func (app *Application) Info(req types.RequestInfo) (resInfo types.ResponseInfo) {
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return types.ResponseInfo{
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Data: fmt.Sprintf("{\"size\":%v}", app.state.Size),
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Version: version.ABCIVersion,
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AppVersion: ProtocolVersion.Uint64(),
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LastBlockHeight: app.state.Height,
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LastBlockAppHash: app.state.AppHash,
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}
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}
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// tx is either "key=value" or just arbitrary bytes
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func (app *Application) DeliverTx(req types.RequestDeliverTx) types.ResponseDeliverTx {
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var key, value []byte
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parts := bytes.Split(req.Tx, []byte("="))
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if len(parts) == 2 {
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key, value = parts[0], parts[1]
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} else {
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key, value = req.Tx, req.Tx
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}
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app.state.db.Set(prefixKey(key), value)
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app.state.Size++
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events := []types.Event{
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{
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Type: "app",
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Attributes: []kv.Pair{
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{Key: []byte("creator"), Value: []byte("Cosmoshi Netowoko")},
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{Key: []byte("key"), Value: key},
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},
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},
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}
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return types.ResponseDeliverTx{Code: code.CodeTypeOK, Events: events}
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}
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func (app *Application) CheckTx(req types.RequestCheckTx) types.ResponseCheckTx {
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return types.ResponseCheckTx{Code: code.CodeTypeOK, GasWanted: 1}
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}
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func (app *Application) Commit() types.ResponseCommit {
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// Using a memdb - just return the big endian size of the db
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appHash := make([]byte, 8)
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binary.PutVarint(appHash, app.state.Size)
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app.state.AppHash = appHash
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app.state.Height++
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saveState(app.state)
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resp := types.ResponseCommit{Data: appHash}
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if app.RetainBlocks > 0 && app.state.Height >= app.RetainBlocks {
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resp.RetainHeight = app.state.Height - app.RetainBlocks + 1
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}
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return resp
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}
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// Returns an associated value or nil if missing.
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func (app *Application) Query(reqQuery types.RequestQuery) (resQuery types.ResponseQuery) {
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if reqQuery.Prove {
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value, err := app.state.db.Get(prefixKey(reqQuery.Data))
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if err != nil {
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panic(err)
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}
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if value == nil {
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resQuery.Log = "does not exist"
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} else {
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resQuery.Log = "exists"
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}
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resQuery.Index = -1 // TODO make Proof return index
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resQuery.Key = reqQuery.Data
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resQuery.Value = value
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resQuery.Height = app.state.Height
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return
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}
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resQuery.Key = reqQuery.Data
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value, err := app.state.db.Get(prefixKey(reqQuery.Data))
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if err != nil {
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panic(err)
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}
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if value == nil {
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resQuery.Log = "does not exist"
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} else {
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resQuery.Log = "exists"
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}
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resQuery.Value = value
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resQuery.Height = app.state.Height
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return resQuery
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}
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