Combine concepts: xpub and last used index

database/database.go

@@ -138,7 +138,11 @@ func CreateNew(dbFile, feeXPub string) error {
 		}
 
 		// Store fee xpub.
-		err = vspBkt.Put(feeXPubK, []byte(feeXPub))
+		xpub := FeeXPub{
+			Key:         feeXPub,
+			LastUsedIdx: 0,
+		}
+		err = insertFeeXPub(tx, xpub)
 		if err != nil {
 			return err
 		}
@@ -311,26 +315,6 @@ func (vdb *VspDatabase) KeyPair() (ed25519.PrivateKey, ed25519.PublicKey, error)
 	return signKey, pubKey, err
 }
 
-// FeeXPub retrieves the extended pubkey used for generating fee addresses
-// from the database.
-func (vdb *VspDatabase) FeeXPub() (string, error) {
-	var feeXPub string
-	err := vdb.db.View(func(tx *bolt.Tx) error {
-		vspBkt := tx.Bucket(vspBktK)
-
-		xpubBytes := vspBkt.Get(feeXPubK)
-		if xpubBytes == nil {
-			return nil
-		}
-
-		feeXPub = string(xpubBytes)
-
-		return nil
-	})
-
-	return feeXPub, err
-}
-
 // CookieSecret retrieves the generated cookie store secret key from the
 // database.
 func (vdb *VspDatabase) CookieSecret() ([]byte, error) {

database/database_test.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2022 The Decred developers
+// Copyright (c) 2020-2024 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
@@ -77,7 +77,7 @@ func TestDatabase(t *testing.T) {
 		"testTicketFeeExpired":  testTicketFeeExpired,
 		"testFilterTickets":     testFilterTickets,
 		"testCountTickets":      testCountTickets,
-		"testAddressIndex":      testAddressIndex,
+		"testFeeXPub":           testFeeXPub,
 		"testDeleteTicket":      testDeleteTicket,
 		"testVoteChangeRecords": testVoteChangeRecords,
 		"testHTTPBackup":        testHTTPBackup,
@@ -134,16 +134,6 @@ func testCreateNew(t *testing.T) {
 	if len(secret) != 32 {
 		t.Fatalf("expected a 32 byte cookie secret, got %d bytes", len(secret))
 	}
-
-	// A newly created DB should store the fee xpub it was initialized with.
-	retrievedXPub, err := db.FeeXPub()
-	if err != nil {
-		t.Fatalf("error getting fee xpub: %v", err)
-	}
-
-	if retrievedXPub != feeXPub {
-		t.Fatalf("expected fee xpub %v, got %v", feeXPub, retrievedXPub)
-	}
 }
 
 func testHTTPBackup(t *testing.T) {

database/feexpub.go

@@ -0,0 +1,75 @@
+// Copyright (c) 2020-2024 The Decred developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package database
+
+import (
+	"fmt"
+
+	bolt "go.etcd.io/bbolt"
+)
+
+type FeeXPub struct {
+	Key         string
+	LastUsedIdx uint32
+}
+
+// insertFeeXPub stores the provided pubkey in the database, regardless of
+// whether a value pre-exists.
+func insertFeeXPub(tx *bolt.Tx, xpub FeeXPub) error {
+	vspBkt := tx.Bucket(vspBktK)
+
+	err := vspBkt.Put(feeXPubK, []byte(xpub.Key))
+	if err != nil {
+		return err
+	}
+
+	return vspBkt.Put(lastAddressIndexK, uint32ToBytes(xpub.LastUsedIdx))
+}
+
+// FeeXPub retrieves the extended pubkey used for generating fee addresses
+// from the database.
+func (vdb *VspDatabase) FeeXPub() (FeeXPub, error) {
+	var feeXPub string
+	var idx uint32
+	err := vdb.db.View(func(tx *bolt.Tx) error {
+		vspBkt := tx.Bucket(vspBktK)
+
+		// Get the key.
+		xpubBytes := vspBkt.Get(feeXPubK)
+		if xpubBytes == nil {
+			return nil
+		}
+		feeXPub = string(xpubBytes)
+
+		// Get the last used address index.
+		idxBytes := vspBkt.Get(lastAddressIndexK)
+		if idxBytes == nil {
+			return nil
+		}
+		idx = bytesToUint32(idxBytes)
+
+		return nil
+	})
+	if err != nil {
+		return FeeXPub{}, fmt.Errorf("could not retrieve fee xpub: %w", err)
+	}
+
+	return FeeXPub{Key: feeXPub, LastUsedIdx: idx}, nil
+}
+
+// SetLastAddressIndex updates the last index used to derive a new fee address
+// from the fee xpub key.
+func (vdb *VspDatabase) SetLastAddressIndex(idx uint32) error {
+	current, err := vdb.FeeXPub()
+	if err != nil {
+		return err
+	}
+
+	current.LastUsedIdx = idx
+
+	return vdb.db.Update(func(tx *bolt.Tx) error {
+		return insertFeeXPub(tx, current)
+	})
+}

database/addressindex_test.go → database/feexpub_test.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2020 The Decred developers
+// Copyright (c) 2020-2024 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
@@ -8,30 +8,35 @@ import (
 	"testing"
 )
 
-func testAddressIndex(t *testing.T) {
-
-	// Getting index before it has been set should return 0.
-	idx, err := db.GetLastAddressIndex()
+func testFeeXPub(t *testing.T) {
+	// A newly created DB should store the fee xpub it was initialized with, and
+	// the last used index should be 0.
+	retrievedXPub, err := db.FeeXPub()
 	if err != nil {
-		t.Fatalf("error getting address index: %v", err)
+		t.Fatalf("error getting fee xpub: %v", err)
 	}
-	if idx != 0 {
+
+	if retrievedXPub.Key != feeXPub {
+		t.Fatalf("expected fee xpub %v, got %v", feeXPub, retrievedXPub.Key)
+	}
+
+	if retrievedXPub.LastUsedIdx != 0 {
 		t.Fatalf("retrieved addr index value didnt match expected")
 	}
 
 	// Update address index.
-	idx = uint32(99)
+	idx := uint32(99)
 	err = db.SetLastAddressIndex(idx)
 	if err != nil {
 		t.Fatalf("error setting address index: %v", err)
 	}
 
 	// Check for updated value.
-	retrievedIdx, err := db.GetLastAddressIndex()
+	retrievedXPub, err = db.FeeXPub()
 	if err != nil {
 		t.Fatalf("error getting address index: %v", err)
 	}
-	if idx != retrievedIdx {
+	if idx != retrievedXPub.LastUsedIdx {
 		t.Fatalf("retrieved addr index value didnt match expected")
 	}
 }

internal/webapi/addressgenerator.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2022 The Decred developers
+// Copyright (c) 2020-2024 The Decred developers
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
@@ -11,6 +11,7 @@ import (
 	"github.com/decred/dcrd/hdkeychain/v3"
 	"github.com/decred/dcrd/txscript/v4/stdaddr"
 	"github.com/decred/slog"
+	"github.com/decred/vspd/database"
 )
 
 type addressGenerator struct {
@@ -20,8 +21,8 @@ type addressGenerator struct {
 	log           slog.Logger
 }
 
-func newAddressGenerator(xPub string, netParams *chaincfg.Params, lastUsedIdx uint32, log slog.Logger) (*addressGenerator, error) {
-	xPubKey, err := hdkeychain.NewKeyFromString(xPub, netParams)
+func newAddressGenerator(xPub database.FeeXPub, netParams *chaincfg.Params, log slog.Logger) (*addressGenerator, error) {
+	xPubKey, err := hdkeychain.NewKeyFromString(xPub.Key, netParams)
 	if err != nil {
 		return nil, err
 	}
@@ -39,7 +40,7 @@ func newAddressGenerator(xPub string, netParams *chaincfg.Params, lastUsedIdx ui
 	return &addressGenerator{
 		external:      external,
 		netParams:     netParams,
-		lastUsedIndex: lastUsedIdx,
+		lastUsedIndex: xPub.LastUsedIdx,
 		log:           log,
 	}, nil
 }

internal/webapi/webapi.go

@@ -95,17 +95,15 @@ func New(vdb *database.VspDatabase, log slog.Logger, dcrd rpc.DcrdConnect,
 		log.Errorf("Could not initialize VSP stats cache: %v", err)
 	}
 
-	// Get the last used address index and the feeXpub from the database, and
-	// use them to initialize the address generator.
-	idx, err := vdb.GetLastAddressIndex()
-	if err != nil {
-		return nil, fmt.Errorf("db.GetLastAddressIndex error: %w", err)
-	}
+	// Get the current fee xpub details from the database.
 	feeXPub, err := vdb.FeeXPub()
 	if err != nil {
-		return nil, fmt.Errorf("db.GetFeeXPub error: %w", err)
+		return nil, fmt.Errorf("db.FeeXPub error: %w", err)
 	}
-	addrGen, err := newAddressGenerator(feeXPub, cfg.Network.Params, idx, log)
+
+	// Use the retrieved pubkey to initialize an address generator which can
+	// later be used to derive new fee addresses.
+	addrGen, err := newAddressGenerator(feeXPub, cfg.Network.Params, log)
 	if err != nil {
 		return nil, fmt.Errorf("failed to initialize fee address generator: %w", err)
 	}