loader: add txn callback when wallet is created

wallet/loader.go

@@ -58,6 +58,7 @@ type Loader struct {
 	wallet         *Wallet
 	localDB        bool
 	walletExists   func() (bool, error)
+	walletCreated  func(db walletdb.ReadWriteTx) error
 	db             walletdb.DB
 	mu             sync.Mutex
 }
@@ -129,6 +130,15 @@ func (l *Loader) RunAfterLoad(fn func(*Wallet)) {
 	}
 }
 
+// OnWalletCreated adds a function that will be executed the wallet structure
+// is initialized in the wallet database. This is useful if users want to add
+// extra fields in the same transaction (eg. to flag wallet existence).
+func (l *Loader) OnWalletCreated(fn func(walletdb.ReadWriteTx) error) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.walletCreated = fn
+}
+
 // CreateNewWallet creates a new wallet using the provided public and private
 // passphrases.  The seed is optional.  If non-nil, addresses are derived from
 // this seed.  If nil, a secure random seed is generated.
@@ -187,16 +197,17 @@ func (l *Loader) createNewWallet(pubPassphrase, privPassphrase,
 
 	// Initialize the newly created database for the wallet before opening.
 	if isWatchingOnly {
-		err := CreateWatchingOnly(
+		err := CreateWatchingOnlyWithCallback(
 			l.db, pubPassphrase, l.chainParams, bday,
+			l.walletCreated,
 		)
 		if err != nil {
 			return nil, err
 		}
 	} else {
-		err := Create(
+		err := CreateWithCallback(
 			l.db, pubPassphrase, privPassphrase, seed,
-			l.chainParams, bday,
+			l.chainParams, bday, l.walletCreated,
 		)
 		if err != nil {
 			return nil, err

wallet/wallet.go

@@ -3665,6 +3665,29 @@ func (w *Wallet) Database() walletdb.DB {
 	return w.db
 }
 
+// CreateWithCallback is the same as Create with an added callback that will be
+// called in the same transaction the wallet structure is initialized.
+func CreateWithCallback(db walletdb.DB, pubPass, privPass, seed []byte,
+	params *chaincfg.Params, birthday time.Time,
+	cb func(walletdb.ReadWriteTx) error) error {
+
+	return create(
+		db, pubPass, privPass, seed, params, birthday, false, cb,
+	)
+}
+
+// CreateWatchingOnlyWithCallback is the same as CreateWatchingOnly with an
+// added callback that will be called in the same transaction the wallet
+// structure is initialized.
+func CreateWatchingOnlyWithCallback(db walletdb.DB, pubPass []byte,
+	params *chaincfg.Params, birthday time.Time,
+	cb func(walletdb.ReadWriteTx) error) error {
+
+	return create(
+		db, pubPass, nil, nil, params, birthday, true, cb,
+	)
+}
+
 // Create creates an new wallet, writing it to an empty database.  If the passed
 // seed is non-nil, it is used.  Otherwise, a secure random seed of the
 // recommended length is generated.
@@ -3672,7 +3695,7 @@ func Create(db walletdb.DB, pubPass, privPass, seed []byte,
 	params *chaincfg.Params, birthday time.Time) error {
 
 	return create(
-		db, pubPass, privPass, seed, params, birthday, false,
+		db, pubPass, privPass, seed, params, birthday, false, nil,
 	)
 }
 
@@ -3684,12 +3707,13 @@ func CreateWatchingOnly(db walletdb.DB, pubPass []byte,
 	params *chaincfg.Params, birthday time.Time) error {
 
 	return create(
-		db, pubPass, nil, nil, params, birthday, true,
+		db, pubPass, nil, nil, params, birthday, true, nil,
 	)
 }
 
 func create(db walletdb.DB, pubPass, privPass, seed []byte,
-	params *chaincfg.Params, birthday time.Time, isWatchingOnly bool) error {
+	params *chaincfg.Params, birthday time.Time, isWatchingOnly bool,
+	cb func(walletdb.ReadWriteTx) error) error {
 
 	if !isWatchingOnly {
 		// If a seed was provided, ensure that it is of valid length. Otherwise,
@@ -3725,7 +3749,17 @@ func create(db walletdb.DB, pubPass, privPass, seed []byte,
 		if err != nil {
 			return err
 		}
-		return wtxmgr.Create(txmgrNs)
+
+		err = wtxmgr.Create(txmgrNs)
+		if err != nil {
+			return err
+		}
+
+		if cb != nil {
+			return cb(tx)
+		}
+
+		return nil
 	})
 }