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Add SimpleDB interface for merkle tree

This commit is contained in:
Ethan Frey 2017-07-26 00:06:12 -04:00
parent 243d767aaa
commit caff0ad01b
3 changed files with 136 additions and 37 deletions
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32
state/kvstore.go
View File

@ -4,6 +4,7 @@ import (
"container/list"
"fmt"
"github.com/tendermint/go-wire/data"
. "github.com/tendermint/tmlibs/common"
)
@ -14,6 +15,37 @@ type KVStore interface {
//----------------------------------------
type Model struct {
Key data.Bytes
Value data.Bytes
}
// What I wished to have...
type SimpleDB interface {
KVStore
Has(key []byte) (has bool)
Remove(key []byte) (value []byte) // returns old value if there was one
List(start, end []byte, limit int) []Model
First(start, end []byte) Model
Last(start, end []byte) Model
// Checkpoint returns the same state, but where writes
// are buffered and don't affect the parent
Checkpoint() SimpleDB
// Commit will take all changes from the checkpoint and write
// them to the parent.
// Returns an error if this is not a child of this one
Commit(SimpleDB) error
// Discard will remove reference to this
Discard()
}
//----------------------------------------
type MemKVStore struct {
m map[string][]byte
}

94
state/merkle/state.go
View File

@ -1,6 +1,10 @@
package merkle
import (
"errors"
"math/rand"
"github.com/tendermint/basecoin/state"
"github.com/tendermint/merkleeyes/iavl"
"github.com/tendermint/tmlibs/merkle"
)
@ -23,16 +27,16 @@ func NewState(tree merkle.Tree, persistent bool) State {
}
}
func (s State) Committed() Bonsai {
return Bonsai{s.committed}
func (s State) Committed() *Bonsai {
return NewBonsai(s.committed)
}
func (s State) Append() Bonsai {
return Bonsai{s.deliverTx}
func (s State) Append() *Bonsai {
return NewBonsai(s.deliverTx)
}
func (s State) Check() Bonsai {
return Bonsai{s.checkTx}
func (s State) Check() *Bonsai {
return NewBonsai(s.checkTx)
}
// Hash updates the tree
@ -66,18 +70,92 @@ func (s *State) Commit() []byte {
return hash
}
// store nonce as it's own type so no one can even try to fake it
type nonce int64
// Bonsai is a deformed tree forced to fit in a small pot
type Bonsai struct {
id nonce
merkle.Tree
}
var _ state.SimpleDB = &Bonsai{}
func NewBonsai(tree merkle.Tree) *Bonsai {
return &Bonsai{
id: nonce(rand.Int63()),
Tree: tree,
}
}
// Get matches the signature of KVStore
func (b Bonsai) Get(key []byte) []byte {
func (b *Bonsai) Get(key []byte) []byte {
_, value, _ := b.Tree.Get(key)
return value
}
// Set matches the signature of KVStore
func (b Bonsai) Set(key, value []byte) {
func (b *Bonsai) Set(key, value []byte) {
b.Tree.Set(key, value)
}
func (b *Bonsai) Remove(key []byte) (value []byte) {
value, _ = b.Tree.Remove(key)
return
}
func (b *Bonsai) List(start, end []byte, limit int) []state.Model {
var res []state.Model
stopAtCount := func(key []byte, value []byte) (stop bool) {
m := state.Model{key, value}
res = append(res, m)
return len(res) >= limit
}
b.Tree.IterateRange(start, end, true, stopAtCount)
return res
}
func (b *Bonsai) First(start, end []byte) state.Model {
var m state.Model
stopAtFirst := func(key []byte, value []byte) (stop bool) {
m = state.Model{key, value}
return true
}
b.Tree.IterateRange(start, end, true, stopAtFirst)
return m
}
func (b *Bonsai) Last(start, end []byte) state.Model {
var m state.Model
stopAtFirst := func(key []byte, value []byte) (stop bool) {
m = state.Model{key, value}
return true
}
b.Tree.IterateRange(start, end, false, stopAtFirst)
return m
}
func (b *Bonsai) Checkpoint() state.SimpleDB {
return &Bonsai{
id: b.id,
Tree: b.Tree.Copy(),
}
}
// Commit will take all changes from the checkpoint and write
// them to the parent.
// Returns an error if this is not a child of this one
func (b *Bonsai) Commit(sub state.SimpleDB) error {
bb, ok := sub.(*Bonsai)
if !ok || (b.id != bb.id) {
return errors.New("Not a sub-transaction")
}
b.Tree = bb.Tree
return nil
}
// Discard will remove reference to this
func (b *Bonsai) Discard() {
b.id = 0
b.Tree = nil
}

47
state/merkle/store.go
View File

@ -28,8 +28,8 @@ type Store struct {
var stateKey = []byte("merkle:state") // Database key for merkle tree save value db values
// MerkleState contains the latest Merkle root hash and the number of times `Commit` has been called
type MerkleState struct {
// ChainState contains the latest Merkle root hash and the number of times `Commit` has been called
type ChainState struct {
Hash []byte
Height uint64
}
@ -74,29 +74,29 @@ func NewStore(dbName string, cacheSize int, logger log.Logger) *Store {
db := dbm.NewDB(name, dbm.LevelDBBackendStr, dir)
tree := iavl.NewIAVLTree(cacheSize, db)
var eyesState MerkleState
var chainState ChainState
if empty {
logger.Info("no existing db, creating new db")
eyesState = MerkleState{
chainState = ChainState{
Hash: tree.Save(),
Height: initialHeight,
}
db.Set(stateKey, wire.BinaryBytes(eyesState))
db.Set(stateKey, wire.BinaryBytes(chainState))
} else {
logger.Info("loading existing db")
eyesStateBytes := db.Get(stateKey)
err = wire.ReadBinaryBytes(eyesStateBytes, &eyesState)
err = wire.ReadBinaryBytes(eyesStateBytes, &chainState)
if err != nil {
logger.Error("error reading MerkleEyesState", "err", err)
panic(err)
}
tree.Load(eyesState.Hash)
tree.Load(chainState.Hash)
}
return &Store{
State: NewState(tree, true),
height: eyesState.Height,
hash: eyesState.Hash,
height: chainState.Height,
hash: chainState.Hash,
persisted: true,
logger: logger,
}
@ -112,7 +112,9 @@ func NewStore(dbName string, cacheSize int, logger log.Logger) *Store {
// Info implements abci.Application. It returns the height, hash and size (in the data).
// The height is the block that holds the transactions, not the apphash itself.
func (s *Store) Info() abci.ResponseInfo {
s.logger.Info("Info synced", "height", s.height, "hash", fmt.Sprintf("%X", s.hash))
s.logger.Info("Info synced",
"height", s.height,
"hash", fmt.Sprintf("%X", s.hash))
return abci.ResponseInfo{
Data: cmn.Fmt("size:%v", s.State.Committed().Size()),
LastBlockHeight: s.height - 1,
@ -124,9 +126,11 @@ func (s *Store) Info() abci.ResponseInfo {
func (s *Store) Commit() abci.Result {
s.hash = s.State.Hash()
s.height++
s.logger.Debug("Commit synced", "height", s.height, "hash", fmt.Sprintf("%X", s.hash))
s.logger.Debug("Commit synced",
"height", s.height,
"hash", fmt.Sprintf("%X", s.hash))
s.State.BatchSet(stateKey, wire.BinaryBytes(MerkleState{
s.State.BatchSet(stateKey, wire.BinaryBytes(ChainState{
Hash: s.hash,
Height: s.height,
}))
@ -144,10 +148,6 @@ func (s *Store) Commit() abci.Result {
// Query implements abci.Application
func (s *Store) Query(reqQuery abci.RequestQuery) (resQuery abci.ResponseQuery) {
if len(reqQuery.Data) == 0 {
return
}
tree := s.State.Committed()
if reqQuery.Height != 0 {
// TODO: support older commits
@ -159,6 +159,8 @@ func (s *Store) Query(reqQuery abci.RequestQuery) (resQuery abci.ResponseQuery)
// set the query response height to current
resQuery.Height = s.height
tree := s.State.Committed()
switch reqQuery.Path {
case "/store", "/key": // Get by key
key := reqQuery.Data // Data holds the key bytes
@ -170,24 +172,11 @@ func (s *Store) Query(reqQuery abci.RequestQuery) (resQuery abci.ResponseQuery)
}
resQuery.Value = value
resQuery.Proof = proof
// TODO: return index too?
} else {
value := tree.Get(key)
resQuery.Value = value
}
case "/index": // Get by Index
index := wire.GetInt64(reqQuery.Data)
key, value := tree.GetByIndex(int(index))
resQuery.Key = key
resQuery.Index = int64(index)
resQuery.Value = value
case "/size": // Get size
size := tree.Size()
sizeBytes := wire.BinaryBytes(size)
resQuery.Value = sizeBytes
default:
resQuery.Code = abci.CodeType_UnknownRequest
resQuery.Log = cmn.Fmt("Unexpected Query path: %v", reqQuery.Path)