Added LatestSnapshot.

diff --git a/blockchain/txdb/snapshot.go b/blockchain/txdb/snapshot.go
index b8a13d7..29844b1 100644 (file)
--- a/blockchain/txdb/snapshot.go
+++ b/blockchain/txdb/snapshot.go
@@ -3,6 +3,7 @@ package txdb
 import (
        "context"
        "fmt"
+       "encoding/json"
 
        "github.com/golang/protobuf/proto"
 
@@ -10,13 +11,18 @@ import (
        "github.com/bytom/errors"
        "github.com/bytom/protocol/patricia"
        "github.com/bytom/protocol/state"
+       "github.com/bytom/protocol/bc"
        dbm "github.com/tendermint/tmlibs/db"
+       . "github.com/tendermint/tmlibs/common"
 )
 
 func calcSnapshotKey(height uint64) []byte {
     return []byte(fmt.Sprintf("S:%v", height))
 }
-/*
+
+func calcLatestSnapshotHeight() []byte {
+       return []byte("LatestSnapshotHeight")
+}
 // DecodeSnapshot decodes a snapshot from the Chain Core's binary,
 // protobuf representation of the snapshot.
 func DecodeSnapshot(data []byte) (*state.Snapshot, error) {
@@ -47,7 +53,36 @@ func DecodeSnapshot(data []byte) (*state.Snapshot, error) {
                Nonces: nonces,
        }, nil
 }
-*/
+
+var latestSnapshotHeight = []byte("latestSnapshotHeight")
+
+type SnapshotHeightJSON struct {
+    Height uint64
+}
+
+func (bsj SnapshotHeightJSON) Save(db dbm.DB) {
+       bytes, err := json.Marshal(bsj)
+       if err != nil {
+               PanicSanity(Fmt("Could not marshal state bytes: %v", err))
+       }
+       db.SetSync(latestSnapshotHeight, bytes)
+}
+
+func LoadSnapshotHeightJSON(db dbm.DB) SnapshotHeightJSON {
+       bytes := db.Get(latestSnapshotHeight)
+       if bytes == nil {
+               return SnapshotHeightJSON{
+                       Height: 0,
+               }
+       }
+       bsj := SnapshotHeightJSON{}
+       err := json.Unmarshal(bytes, &bsj)
+       if err != nil {
+               PanicCrisis(Fmt("Could not unmarshal bytes: %X", bytes))
+       }
+       return bsj
+}
+
 
 func storeStateSnapshot(ctx context.Context, db dbm.DB, snapshot *state.Snapshot, blockHeight uint64) error {
        var storedSnapshot storage.Snapshot
@@ -76,26 +111,17 @@ func storeStateSnapshot(ctx context.Context, db dbm.DB, snapshot *state.Snapshot
 
        // set new snapshot.
        db.Set(calcSnapshotKey(blockHeight), b)
+       SnapshotHeightJSON{Height: blockHeight}.Save(db)
        //TO DO: delete old snapshot.
        db.SetSync(nil, nil)
        return errors.Wrap(err, "deleting old snapshots")
 }
 
-/*
-func getStateSnapshot(ctx context.Context, db pg.DB) (*state.Snapshot, uint64, error) {
-       const q = `
-               SELECT data, height FROM snapshots ORDER BY height DESC LIMIT 1
-       `
-       var (
-               data   []byte
-               height uint64
-       )
-
-       err := db.QueryRowContext(ctx, q).Scan(&data, &height)
-       if err == sql.ErrNoRows {
-               return state.Empty(), 0, nil
-       } else if err != nil {
-               return nil, height, errors.Wrap(err, "retrieving state snapshot blob")
+func getStateSnapshot(ctx context.Context, db dbm.DB) (*state.Snapshot, uint64, error) {
+       height := LoadSnapshotHeightJSON(db).Height
+       data := db.Get(calcSnapshotKey(height))
+       if data == nil {
+               return nil, height, errors.New("no this snapshot.")
        }
 
        snapshot, err := DecodeSnapshot(data)
@@ -105,6 +131,7 @@ func getStateSnapshot(ctx context.Context, db pg.DB) (*state.Snapshot, uint64, e
        return snapshot, height, nil
 }
 
+/*
 // getRawSnapshot returns the raw, protobuf-encoded snapshot data at the
 // provided height.
 func getRawSnapshot(ctx context.Context, db pg.DB, height uint64) (data []byte, err error) {

diff --git a/blockchain/txdb/store.go b/blockchain/txdb/store.go
index 4f24385..fa0ee8d 100644 (file)
--- a/blockchain/txdb/store.go
+++ b/blockchain/txdb/store.go
@@ -104,12 +104,9 @@ func (s *Store) GetBlock(height uint64) (*legacy.Block, error) {
 
 // LatestSnapshot returns the most recent state snapshot stored in
 // the database and its corresponding block height.
-/*
 func (s *Store) LatestSnapshot(ctx context.Context) (*state.Snapshot, uint64, error) {
-//     return getStateSnapshot(ctx, s.db)
-//    return nil, 0, nil
+       return getStateSnapshot(ctx, s.db)
 }
-*/
 
 /*
 // LatestSnapshotInfo returns the height and size of the most recent

diff --git a/protocol/protocol.go b/protocol/protocol.go
index 0170575..1b22ce9 100644 (file)
--- a/protocol/protocol.go
+++ b/protocol/protocol.go
@@ -33,7 +33,7 @@ var (
 type Store interface {
        Height() uint64
        GetBlock(uint64) (*legacy.Block, error)
-//     LatestSnapshot(context.Context) (*state.Snapshot, uint64, error)
+       LatestSnapshot(context.Context) (*state.Snapshot, uint64, error)
 
        SaveBlock(*legacy.Block) error
        FinalizeBlock(context.Context, uint64) error