github.com/pokt-network/tendermint@v0.32.11-0.20230426215212-59310158d3e9/abci/example/kvstore/kvstore.go (about)

     1  package kvstore
     2  
     3  import (
     4  	"bytes"
     5  	"encoding/binary"
     6  	"encoding/json"
     7  	"fmt"
     8  
     9  	dbm "github.com/tendermint/tm-db"
    10  
    11  	"github.com/tendermint/tendermint/abci/example/code"
    12  	"github.com/tendermint/tendermint/abci/types"
    13  	"github.com/tendermint/tendermint/libs/kv"
    14  	"github.com/tendermint/tendermint/version"
    15  )
    16  
    17  var (
    18  	stateKey        = []byte("stateKey")
    19  	kvPairPrefixKey = []byte("kvPairKey:")
    20  
    21  	ProtocolVersion version.Protocol = 0x1
    22  )
    23  
    24  type State struct {
    25  	db      dbm.DB
    26  	Size    int64  `json:"size"`
    27  	Height  int64  `json:"height"`
    28  	AppHash []byte `json:"app_hash"`
    29  }
    30  
    31  func loadState(db dbm.DB) State {
    32  	var state State
    33  	state.db = db
    34  	stateBytes, err := db.Get(stateKey)
    35  	if err != nil {
    36  		panic(err)
    37  	}
    38  	if len(stateBytes) == 0 {
    39  		return state
    40  	}
    41  	err = json.Unmarshal(stateBytes, &state)
    42  	if err != nil {
    43  		panic(err)
    44  	}
    45  	return state
    46  }
    47  
    48  func saveState(state State) {
    49  	stateBytes, err := json.Marshal(state)
    50  	if err != nil {
    51  		panic(err)
    52  	}
    53  	state.db.Set(stateKey, stateBytes)
    54  }
    55  
    56  func prefixKey(key []byte) []byte {
    57  	return append(kvPairPrefixKey, key...)
    58  }
    59  
    60  //---------------------------------------------------
    61  
    62  var _ types.Application = (*Application)(nil)
    63  
    64  type Application struct {
    65  	types.BaseApplication
    66  
    67  	state        State
    68  	RetainBlocks int64 // blocks to retain after commit (via ResponseCommit.RetainHeight)
    69  }
    70  
    71  func NewApplication() *Application {
    72  	state := loadState(dbm.NewMemDB())
    73  	return &Application{state: state}
    74  }
    75  
    76  func (app *Application) Info(req types.RequestInfo) (resInfo types.ResponseInfo) {
    77  	return types.ResponseInfo{
    78  		Data:             fmt.Sprintf("{\"size\":%v}", app.state.Size),
    79  		Version:          version.ABCIVersion,
    80  		AppVersion:       ProtocolVersion.Uint64(),
    81  		LastBlockHeight:  app.state.Height,
    82  		LastBlockAppHash: app.state.AppHash,
    83  	}
    84  }
    85  
    86  // tx is either "key=value" or just arbitrary bytes
    87  func (app *Application) DeliverTx(req types.RequestDeliverTx) types.ResponseDeliverTx {
    88  	var key, value []byte
    89  	parts := bytes.Split(req.Tx, []byte("="))
    90  	if len(parts) == 2 {
    91  		key, value = parts[0], parts[1]
    92  	} else {
    93  		key, value = req.Tx, req.Tx
    94  	}
    95  
    96  	app.state.db.Set(prefixKey(key), value)
    97  	app.state.Size++
    98  
    99  	events := []types.Event{
   100  		{
   101  			Type: "app",
   102  			Attributes: []kv.Pair{
   103  				{Key: []byte("creator"), Value: []byte("Cosmoshi Netowoko")},
   104  				{Key: []byte("key"), Value: key},
   105  			},
   106  		},
   107  	}
   108  
   109  	return types.ResponseDeliverTx{Code: code.CodeTypeOK, Events: events}
   110  }
   111  
   112  func (app *Application) CheckTx(req types.RequestCheckTx) types.ResponseCheckTx {
   113  	return types.ResponseCheckTx{Code: code.CodeTypeOK, GasWanted: 1}
   114  }
   115  
   116  func (app *Application) Commit() types.ResponseCommit {
   117  	// Using a memdb - just return the big endian size of the db
   118  	appHash := make([]byte, 8)
   119  	binary.PutVarint(appHash, app.state.Size)
   120  	app.state.AppHash = appHash
   121  	app.state.Height++
   122  	saveState(app.state)
   123  
   124  	resp := types.ResponseCommit{Data: appHash}
   125  	if app.RetainBlocks > 0 && app.state.Height >= app.RetainBlocks {
   126  		resp.RetainHeight = app.state.Height - app.RetainBlocks + 1
   127  	}
   128  	return resp
   129  }
   130  
   131  // Returns an associated value or nil if missing.
   132  func (app *Application) Query(reqQuery types.RequestQuery) (resQuery types.ResponseQuery) {
   133  	if reqQuery.Prove {
   134  		value, err := app.state.db.Get(prefixKey(reqQuery.Data))
   135  		if err != nil {
   136  			panic(err)
   137  		}
   138  		if value == nil {
   139  			resQuery.Log = "does not exist"
   140  		} else {
   141  			resQuery.Log = "exists"
   142  		}
   143  		resQuery.Index = -1 // TODO make Proof return index
   144  		resQuery.Key = reqQuery.Data
   145  		resQuery.Value = value
   146  		resQuery.Height = app.state.Height
   147  
   148  		return
   149  	}
   150  
   151  	resQuery.Key = reqQuery.Data
   152  	value, err := app.state.db.Get(prefixKey(reqQuery.Data))
   153  	if err != nil {
   154  		panic(err)
   155  	}
   156  	if value == nil {
   157  		resQuery.Log = "does not exist"
   158  	} else {
   159  		resQuery.Log = "exists"
   160  	}
   161  	resQuery.Value = value
   162  	resQuery.Height = app.state.Height
   163  
   164  	return resQuery
   165  }