wallet: deprecate exported header extraction funcs

This deprecates  udb.ExtractBlockHeaderParentHash and
udb.ExtractBlockHeaderHeight in preference of using an
 unexported copy of the extract function at the call site.

wallet/rescan.go

@@ -6,6 +6,7 @@
 package wallet
 
 import (
+	"encoding/binary"
 	"context"
 	"time"
 
@@ -62,6 +63,20 @@ func NewRescanFilter(addresses []dcrutil.Address, unspentOutPoints []*wire.OutPo
 	return filter
 }
 
+// extractBlockHeaderHeight fetches the block height from wire encoded block 
+// header bytes.
+func extractBlockHeaderHeight(header []byte) int32 {
+	const heightOffset = 128
+	return int32(binary.LittleEndian.Uint32(header[heightOffset:]))
+}
+
+// extractBlockHeaderUnixTime fetches the unix timestamp from wire encoded 
+// block header bytes.
+func extractBlockHeaderUnixTime(header []byte) uint32 {
+	const timestampOffset = 136
+	return binary.LittleEndian.Uint32(header[timestampOffset:])
+}
+
 // AddAddress adds an address to the filter if it does not already exist.
 func (f *RescanFilter) AddAddress(a dcrutil.Address) {
 	switch a := a.(type) {
@@ -269,7 +284,7 @@ func (w *Wallet) Rescan(ctx context.Context, n NetworkBackend, startHash *chainh
 		if err != nil {
 			return err
 		}
-		startHeight = udb.ExtractBlockHeaderHeight(header)
+		startHeight = extractBlockHeaderHeight(header)
 		return nil
 	})
 	if err != nil {

wallet/udb/txmined.go

@@ -458,7 +458,7 @@ func extractBlockHeaderParentHash(header []byte) []byte {
 // ExtractBlockHeaderParentHash subslices the header to return the bytes of the
 // parent block's hash.  Must only be called on known good input.
 //
-// TODO: This really should not be exported by this package.
+// DEPRECATED: to be removed in the next major release.
 func ExtractBlockHeaderParentHash(header []byte) []byte {
 	return extractBlockHeaderParentHash(header)
 }
@@ -476,7 +476,7 @@ func extractBlockHeaderHeight(header []byte) int32 {
 // ExtractBlockHeaderHeight returns the height field that is encoded in the
 // header.  Must only be called on known good input.
 //
-// TODO: This really should not be exported by this package.
+// DEPRECATED: to be removed in the next major release.
 func ExtractBlockHeaderHeight(header []byte) int32 {
 	return extractBlockHeaderHeight(header)
 }
@@ -490,7 +490,7 @@ func extractBlockHeaderUnixTime(header []byte) uint32 {
 // header.  Must only be called on known good input.  Header timestamps are only
 // 4 bytes and this value is actually limited to a maximum unix time of 2^32-1.
 //
-// TODO: This really should not be exported by this package.
+// DEPRECATED: to be removed in the next major release.
 func ExtractBlockHeaderTime(header []byte) int64 {
 	return int64(extractBlockHeaderUnixTime(header))
 }

wallet/wallet.go

@@ -2223,7 +2223,7 @@ func (w *Wallet) BlockInfo(blockID *BlockIdentifier) (*BlockInfo, error) {
 		if err != nil {
 			return err
 		}
-		height := udb.ExtractBlockHeaderHeight(header)
+		height := extractBlockHeaderHeight(header)
 		inMainChain, invalidated := w.TxStore.BlockInMainChain(dbtx, blockHash)
 		var confs int32
 		if inMainChain {
@@ -2234,7 +2234,7 @@ func (w *Wallet) BlockInfo(blockID *BlockIdentifier) (*BlockInfo, error) {
 			Height:           height,
 			Confirmations:    confs,
 			Header:           header,
-			Timestamp:        udb.ExtractBlockHeaderTime(header),
+			Timestamp:        int64(extractBlockHeaderUnixTime(header)),
 			StakeInvalidated: invalidated,
 		}
 		return nil