db/prefixes/prefixes.go

@@ -63,6 +63,88 @@ type PrefixRowKV struct {
 	Value interface{}
 }
 
+type UndoKey struct {
+	Prefix []byte `json:"prefix"`
+	Height uint64 `json:"height"`
+}
+
+type UndoValue struct {
+	Data []byte `json:"data"`
+}
+
+func (k *UndoKey) PackKey() []byte {
+	prefixLen := 1
+	// b'>L'
+	n := prefixLen + 8
+	key := make([]byte, n)
+	copy(key, k.Prefix)
+	binary.BigEndian.PutUint64(key[prefixLen:], k.Height)
+
+	return key
+}
+
+func (v *UndoValue) PackValue() []byte {
+	len := len(v.Data)
+	value := make([]byte, len)
+	copy(value, v.Data)
+
+	return value
+}
+
+func UndoKeyPackPartialNFields(nFields int) func(*UndoKey) []byte {
+	return func(u *UndoKey) []byte {
+		return UndoKeyPackPartial(u, nFields)
+	}
+}
+
+func UndoKeyPackPartial(k *UndoKey, nFields int) []byte {
+	// Limit nFields between 0 and number of fields, we always at least need
+	// the prefix, and we never need to iterate past the number of fields.
+	if nFields > 1 {
+		nFields = 1
+	}
+	if nFields < 0 {
+		nFields = 0
+	}
+
+	// b'>4sLH'
+	prefixLen := 1
+	var n = prefixLen
+	for i := 0; i <= nFields; i++ {
+		switch i {
+		case 1:
+			n += 8
+		}
+	}
+
+	key := make([]byte, n)
+
+	for i := 0; i <= nFields; i++ {
+		switch i {
+		case 0:
+			copy(key, k.Prefix)
+		case 1:
+			binary.BigEndian.PutUint64(key[prefixLen:], k.Height)
+		}
+	}
+
+	return key
+}
+
+func UndoKeyUnpack(key []byte) *UndoKey {
+	prefixLen := 1
+	return &UndoKey{
+		Prefix: key[:prefixLen],
+		Height: binary.BigEndian.Uint64(key[prefixLen:]),
+	}
+}
+
+func UndoValueUnpack(value []byte) *UndoValue {
+	return &UndoValue{
+		Data: value,
+	}
+}
+
 type UTXOKey struct {
 	Prefix []byte `json:"prefix"`
 	HashX  []byte `json:"hashx"`
@@ -2661,7 +2743,7 @@ func UnpackGenericKey(key []byte) (byte, interface{}, error) {
 		return RepostedClaim, RepostedKeyUnpack(key), nil
 
 	case Undo:
-		return 0x0, nil, errors.Base("key unpack function for %v not implemented", firstByte)
+		return Undo, UndoKeyUnpack(key), nil
 	case ClaimDiff:
 		return ClaimDiff, TouchedOrDeletedClaimKeyUnpack(key), nil
 
@@ -2736,7 +2818,7 @@ func UnpackGenericValue(key, value []byte) (byte, interface{}, error) {
 		return RepostedClaim, RepostedValueUnpack(value), nil
 
 	case Undo:
-		return 0x0, nil, errors.Base("value unpack not implemented for key %v", key)
+		return Undo, UndoValueUnpack(value), nil
 	case ClaimDiff:
 		return ClaimDiff, TouchedOrDeletedClaimValueUnpack(value), nil
 

db/prefixes/prefixes_test.go

@@ -44,6 +44,82 @@ func testInit(filePath string) (*grocksdb.DB, [][]string, func()) {
 	return db, records, toDefer
 }
 
+func TestUndo(t *testing.T) {
+
+	filePath := "../../resources/undo.csv"
+
+	wOpts := grocksdb.NewDefaultWriteOptions()
+	db, records, toDefer := testInit(filePath)
+	defer toDefer()
+	for _, record := range records {
+		key, err := hex.DecodeString(record[0])
+		if err != nil {
+			log.Println(err)
+		}
+		val, err := hex.DecodeString(record[1])
+		if err != nil {
+			log.Println(err)
+		}
+		db.Put(wOpts, key, val)
+	}
+	// test prefix
+	options := dbpkg.NewIterateOptions().WithPrefix([]byte{prefixes.Undo}).WithIncludeValue(true)
+	ch := dbpkg.Iter(db, options)
+	var i = 0
+	for kv := range ch {
+		// log.Println(kv.Key)
+		gotKey := kv.Key.(*prefixes.UndoKey).PackKey()
+
+		keyPartial1 := prefixes.UndoKeyPackPartial(kv.Key.(*prefixes.UndoKey), 1)
+
+		// Check pack partial for sanity
+		if !bytes.HasPrefix(gotKey, keyPartial1) {
+			t.Errorf("%+v should be prefix of %+v\n", keyPartial1, gotKey)
+		}
+
+		got := kv.Value.(*prefixes.UndoValue).PackValue()
+		wantKey, err := hex.DecodeString(records[i][0])
+		if err != nil {
+			log.Println(err)
+		}
+		want, err := hex.DecodeString(records[i][1])
+		if err != nil {
+			log.Println(err)
+		}
+		if !bytes.Equal(gotKey, wantKey) {
+			t.Errorf("gotKey: %+v, wantKey: %+v\n", got, want)
+		}
+		if !bytes.Equal(got, want) {
+			t.Errorf("got: %+v, want: %+v\n", got, want)
+		}
+		i++
+	}
+
+	// Test start / stop
+	start, err := hex.DecodeString(records[0][0])
+	if err != nil {
+		log.Println(err)
+	}
+	stop, err := hex.DecodeString(records[1][0])
+	if err != nil {
+		log.Println(err)
+	}
+	options2 := dbpkg.NewIterateOptions().WithStart(start).WithStop(stop).WithIncludeValue(true)
+	ch2 := dbpkg.Iter(db, options2)
+	i = 0
+	for kv := range ch2 {
+		got := kv.Value.(*prefixes.UndoValue).PackValue()
+		want, err := hex.DecodeString(records[i][1])
+		if err != nil {
+			log.Println(err)
+		}
+		if !bytes.Equal(got, want) {
+			t.Errorf("got: %+v, want: %+v\n", got, want)
+		}
+		i++
+	}
+}
+
 func TestBlockHash(t *testing.T) {
 
 	filePath := "../../resources/block_hash.csv"

main.go

@@ -38,7 +38,7 @@ func main() {
 
 		options := &db.IterOptions{
 			FillCache:    false,
-			Prefix:       []byte{prefixes.BlockHash},
+			Prefix:       []byte{prefixes.Undo},
 			Start:        nil,
 			Stop:         nil,
 			IncludeStart: true,
@@ -49,7 +49,7 @@ func main() {
 			RawValue:     true,
 		}
 
-		db.ReadWriteRawN(dbVal, options, "./resources/block_hash.csv", 10)
+		db.ReadWriteRawN(dbVal, options, "./resources/undo.csv", 2)
 
 		return
 	}