db/prefixes/generic.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"github.com/go-restruct/restruct"
+	"github.com/lbryio/herald.go/internal"
 	"github.com/lbryio/lbcd/chaincfg/chainhash"
 )
 
@@ -59,6 +60,34 @@ func (kv *BlockTxsValue) Unpack(buf []byte, order binary.ByteOrder) ([]byte, err
 	return buf[offset:], nil
 }
 
+// Struct BigEndianChainHash is a chainhash.Hash stored in external
+// byte-order (opposite of other 32 byte chainhash.Hash values). In order
+// to reuse chainhash.Hash we need to correct the byte-order.
+// Currently this type is used for field Genesis of DBStateValue.
+
+func (kv *BigEndianChainHash) SizeOf() int {
+	return chainhash.HashSize
+}
+
+func (kv *BigEndianChainHash) Pack(buf []byte, order binary.ByteOrder) ([]byte, error) {
+	offset := 0
+	hash := kv.CloneBytes()
+	// HACK: Instances of chainhash.Hash use the internal byte-order.
+	// Python scribe writes bytes of genesis hash in external byte-order.
+	internal.ReverseBytesInPlace(hash)
+	offset += copy(buf[offset:chainhash.HashSize], hash[:])
+	return buf[offset:], nil
+}
+
+func (kv *BigEndianChainHash) Unpack(buf []byte, order binary.ByteOrder) ([]byte, error) {
+	offset := 0
+	offset += copy(kv.Hash[:], buf[offset:32])
+	// HACK: Instances of chainhash.Hash use the internal byte-order.
+	// Python scribe writes bytes of genesis hash in external byte-order.
+	internal.ReverseBytesInPlace(kv.Hash[:])
+	return buf[offset:], nil
+}
+
 func genericNew(prefix []byte, key bool) (interface{}, error) {
 	t, ok := prefixRegistry[prefix[0]]
 	if !ok {

db/prefixes/prefixes.go

@@ -182,12 +182,25 @@ func NewLengthEncodedPartialClaimId(s string) LengthEncodedPartialClaimId {
 	}
 }
 
+type BigEndianChainHash struct {
+	chainhash.Hash
+}
+
+func NewBigEndianChainHash(hash *chainhash.Hash) BigEndianChainHash {
+	if hash != nil {
+		return BigEndianChainHash{
+			*hash,
+		}
+	}
+	return BigEndianChainHash{}
+}
+
 type DBStateKey struct {
 	Prefix []byte `struct:"[1]byte" json:"prefix"`
 }
 
 type DBStateValue struct {
-	Genesis        *chainhash.Hash
+	Genesis        BigEndianChainHash
 	Height         uint32
 	TxCount        uint32
 	Tip            *chainhash.Hash
@@ -203,7 +216,7 @@ type DBStateValue struct {
 
 func NewDBStateValue() *DBStateValue {
 	return &DBStateValue{
-		Genesis:        new(chainhash.Hash),
+		Genesis:        NewBigEndianChainHash(nil),
 		Height:         0,
 		TxCount:        0,
 		Tip:            new(chainhash.Hash),
@@ -237,7 +250,11 @@ func (v *DBStateValue) PackValue() []byte {
 	// b'>32sLL32sLLBBlllL'
 	n := 32 + 4 + 4 + 32 + 4 + 4 + 1 + 1 + 4 + 4 + 4 + 4
 	value := make([]byte, n)
-	copy(value, v.Genesis[:32])
+	genesis := v.Genesis.CloneBytes()
+	// HACK: Instances of chainhash.Hash use the internal byte-order.
+	// Python scribe writes bytes of genesis hash in external byte-order.
+	internal.ReverseBytesInPlace(genesis)
+	copy(value, genesis[:32])
 	binary.BigEndian.PutUint32(value[32:], v.Height)
 	binary.BigEndian.PutUint32(value[32+4:], v.TxCount)
 	copy(value[32+4+4:], v.Tip[:32])
@@ -286,7 +303,7 @@ func DBStateValueUnpack(value []byte) *DBStateValue {
 	// Instances of chainhash.Hash should use the internal byte-order.
 	internal.ReverseBytesInPlace(genesis[:])
 	x := &DBStateValue{
-		Genesis:        genesis,
+		Genesis:        NewBigEndianChainHash(genesis),
 		Height:         binary.BigEndian.Uint32(value[32:]),
 		TxCount:        binary.BigEndian.Uint32(value[32+4:]),
 		Tip:            tip,
@@ -711,7 +728,7 @@ type BlockTxsKey struct {
 }
 
 type BlockTxsValue struct {
-	TxHashes []*chainhash.Hash `struct-while:"!_eof" json:"tx_hashes"`
+	TxHashes []*chainhash.Hash `struct:"*[32]byte" struct-while:"!_eof" json:"tx_hashes"`
 }
 
 func (k *BlockTxsKey) NewBlockTxsKey(height uint32) *BlockTxsKey {

server/server.go

@@ -277,9 +277,9 @@ func MakeHubServer(grp *stop.Group, args *Args) *Server {
 
 	// Determine which chain to use based on db and cli values
 	dbChain := (*chaincfg.Params)(nil)
-	if myDB != nil && myDB.LastState != nil && myDB.LastState.Genesis != nil {
+	if myDB != nil && myDB.LastState != nil {
 		// The chain params can be inferred from DBStateValue.
-		switch *myDB.LastState.Genesis {
+		switch myDB.LastState.Genesis.Hash {
 		case *chaincfg.MainNetParams.GenesisHash:
 			dbChain = &chaincfg.MainNetParams
 		case *chaincfg.TestNet3Params.GenesisHash: