wallet: break FetchInputInfo into two methods

wallet/utxos.go

@@ -104,86 +104,123 @@ func (w *Wallet) UnspentOutputs(policy OutputSelectionPolicy) ([]*TransactionOut
 
 // FetchInputInfo queries for the wallet's knowledge of the passed outpoint. If
 // the wallet determines this output is under its control, then the original
-// full transaction, the target txout and the number of confirmations are
-// returned. Otherwise, a non-nil error value of ErrNotMine is returned instead.
+// full transaction, the target txout, the derivation info and the number of
+// confirmations are returned. Otherwise, a non-nil error value of ErrNotMine
+// is returned instead.
+//
+// NOTE: This method is kept for compatibility.
 func (w *Wallet) FetchInputInfo(prevOut *wire.OutPoint) (*wire.MsgTx,
 	*wire.TxOut, *psbt.Bip32Derivation, int64, error) {
 
+	tx, txOut, confs, err := w.FetchOutpointInfo(prevOut)
+	if err != nil {
+		return nil, nil, nil, 0, err
+	}
+
+	derivation, err := w.FetchDerivationInfo(txOut.PkScript)
+	if err != nil {
+		return nil, nil, nil, 0, err
+	}
+
+	return tx, txOut, derivation, confs, nil
+}
+
+// fetchOutputAddr attempts to fetch the managed address corresponding to the
+// passed output script. This function is used to look up the proper key which
+// should be used to sign a specified input.
+func (w *Wallet) fetchOutputAddr(script []byte) (waddrmgr.ManagedAddress, error) {
+	_, addrs, _, err := txscript.ExtractPkScriptAddrs(script, w.chainParams)
+	if err != nil {
+		return nil, err
+	}
+
+	// If the case of a multi-sig output, several address may be extracted.
+	// Therefore, we simply select the key for the first address we know
+	// of.
+	for _, addr := range addrs {
+		addr, err := w.AddressInfo(addr)
+		if err == nil {
+			return addr, nil
+		}
+	}
+
+	return nil, ErrNotMine
+}
+
+// FetchOutpointInfo queries for the wallet's knowledge of the passed outpoint.
+// If the wallet determines this output is under its control, the original full
+// transaction, the target txout and the number of confirmations are returned.
+// Otherwise, a non-nil error value of ErrNotMine is returned instead.
+func (w *Wallet) FetchOutpointInfo(prevOut *wire.OutPoint) (*wire.MsgTx,
+	*wire.TxOut, int64, error) {
+
 	// We manually look up the output within the tx store.
 	txid := &prevOut.Hash
 	txDetail, err := UnstableAPI(w).TxDetails(txid)
 	if err != nil {
-		return nil, nil, nil, 0, err
+		return nil, nil, 0, err
 	} else if txDetail == nil {
-		return nil, nil, nil, 0, ErrNotMine
+		return nil, nil, 0, ErrNotMine
 	}
 
 	// With the output retrieved, we'll make an additional check to ensure
-	// we actually have control of this output. We do this because the check
-	// above only guarantees that the transaction is somehow relevant to us,
-	// like in the event of us being the sender of the transaction.
+	// we actually have control of this output. We do this because the
+	// check above only guarantees that the transaction is somehow relevant
+	// to us, like in the event of us being the sender of the transaction.
 	numOutputs := uint32(len(txDetail.TxRecord.MsgTx.TxOut))
 	if prevOut.Index >= numOutputs {
-		return nil, nil, nil, 0, fmt.Errorf("invalid output index %v for "+
+		return nil, nil, 0, fmt.Errorf("invalid output index %v for "+
 			"transaction with %v outputs", prevOut.Index,
 			numOutputs)
 	}
+
 	pkScript := txDetail.TxRecord.MsgTx.TxOut[prevOut.Index].PkScript
-	addr, err := w.fetchOutputAddr(pkScript)
-	if err != nil {
-		return nil, nil, nil, 0, err
-	}
-	pubKeyAddr, ok := addr.(waddrmgr.ManagedPubKeyAddress)
-	if !ok {
-		return nil, nil, nil, 0, ErrNotMine
-	}
-	keyScope, derivationPath, _ := pubKeyAddr.DerivationInfo()
 
 	// Determine the number of confirmations the output currently has.
 	_, currentHeight, err := w.chainClient.GetBestBlock()
 	if err != nil {
-		return nil, nil, nil, 0, fmt.Errorf("unable to retrieve current "+
+		return nil, nil, 0, fmt.Errorf("unable to retrieve current "+
 			"height: %w", err)
 	}
+
 	confs := int64(0)
 	if txDetail.Block.Height != -1 {
 		confs = int64(currentHeight - txDetail.Block.Height)
 	}
 
 	return &txDetail.TxRecord.MsgTx, &wire.TxOut{
-			Value:    txDetail.TxRecord.MsgTx.TxOut[prevOut.Index].Value,
-			PkScript: pkScript,
-		}, &psbt.Bip32Derivation{
-			PubKey:               pubKeyAddr.PubKey().SerializeCompressed(),
-			MasterKeyFingerprint: derivationPath.MasterKeyFingerprint,
-			Bip32Path: []uint32{
-				keyScope.Purpose + hdkeychain.HardenedKeyStart,
-				keyScope.Coin + hdkeychain.HardenedKeyStart,
-				derivationPath.Account,
-				derivationPath.Branch,
-				derivationPath.Index,
-			},
-		}, confs, nil
+		Value:    txDetail.TxRecord.MsgTx.TxOut[prevOut.Index].Value,
+		PkScript: pkScript,
+	}, confs, nil
 }
 
-// fetchOutputAddr attempts to fetch the managed address corresponding to the
-// passed output script. This function is used to look up the proper key which
-// should be used to sign a specified input.
-func (w *Wallet) fetchOutputAddr(script []byte) (waddrmgr.ManagedAddress, error) {
-	_, addrs, _, err := txscript.ExtractPkScriptAddrs(script, w.chainParams)
+// FetchDerivationInfo queries for the wallet's knowledge of the passed
+// pkScript and constructs the derivation info and returns it.
+func (w *Wallet) FetchDerivationInfo(pkScript []byte) (*psbt.Bip32Derivation,
+	error) {
+
+	addr, err := w.fetchOutputAddr(pkScript)
 	if err != nil {
 		return nil, err
 	}
 
-	// If the case of a multi-sig output, several address may be extracted.
-	// Therefore, we simply select the key for the first address we know
-	// of.
-	for _, addr := range addrs {
-		addr, err := w.AddressInfo(addr)
-		if err == nil {
-			return addr, nil
-		}
+	pubKeyAddr, ok := addr.(waddrmgr.ManagedPubKeyAddress)
+	if !ok {
+		return nil, ErrNotMine
 	}
+	keyScope, derivationPath, _ := pubKeyAddr.DerivationInfo()
 
-	return nil, ErrNotMine
+	derivation := &psbt.Bip32Derivation{
+		PubKey:               pubKeyAddr.PubKey().SerializeCompressed(),
+		MasterKeyFingerprint: derivationPath.MasterKeyFingerprint,
+		Bip32Path: []uint32{
+			keyScope.Purpose + hdkeychain.HardenedKeyStart,
+			keyScope.Coin + hdkeychain.HardenedKeyStart,
+			derivationPath.Account,
+			derivationPath.Branch,
+			derivationPath.Index,
+		},
+	}
+
+	return derivation, nil
 }

wallet/utxos_test.go

@@ -12,6 +12,7 @@ import (
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/btcsuite/btcwallet/waddrmgr"
+	"github.com/stretchr/testify/require"
 )
 
 // TestFetchInputInfo checks that the wallet can gather information about an
@@ -90,3 +91,75 @@ func TestFetchInputInfo(t *testing.T) {
 			confirmations, 0-testBlockHeight)
 	}
 }
+
+// TestFetchOutpointInfo checks that the wallet can gather information about an
+// output based on the outpoint.
+func TestFetchOutpointInfo(t *testing.T) {
+	t.Parallel()
+
+	w, cleanup := testWallet(t)
+	defer cleanup()
+
+	// Create an address we can use to send some coins to.
+	addr, err := w.CurrentAddress(0, waddrmgr.KeyScopeBIP0084)
+	require.NoError(t, err)
+	p2shAddr, err := txscript.PayToAddrScript(addr)
+	require.NoError(t, err)
+
+	// Add an output paying to the wallet's address to the database.
+	utxOut := wire.NewTxOut(100000, p2shAddr)
+	incomingTx := &wire.MsgTx{
+		TxIn:  []*wire.TxIn{{}},
+		TxOut: []*wire.TxOut{utxOut},
+	}
+	addUtxo(t, w, incomingTx)
+
+	// Look up the UTXO for the outpoint now and compare it to our
+	// expectations.
+	prevOut := &wire.OutPoint{
+		Hash:  incomingTx.TxHash(),
+		Index: 0,
+	}
+	tx, out, confirmations, err := w.FetchOutpointInfo(prevOut)
+	require.NoError(t, err)
+
+	require.Equal(t, utxOut.PkScript, out.PkScript)
+	require.Equal(t, utxOut.Value, out.Value)
+	require.Equal(t, utxOut.PkScript, tx.TxOut[prevOut.Index].PkScript)
+	require.Equal(t, int64(0-testBlockHeight), confirmations)
+}
+
+// TestFetchDerivationInfo checks that the wallet can gather the derivation
+// info about an output based on the pkScript.
+func TestFetchDerivationInfo(t *testing.T) {
+	t.Parallel()
+
+	w, cleanup := testWallet(t)
+	defer cleanup()
+
+	// Create an address we can use to send some coins to.
+	addr, err := w.CurrentAddress(0, waddrmgr.KeyScopeBIP0084)
+	require.NoError(t, err)
+	p2shAddr, err := txscript.PayToAddrScript(addr)
+	require.NoError(t, err)
+
+	// Add an output paying to the wallet's address to the database.
+	utxOut := wire.NewTxOut(100000, p2shAddr)
+	incomingTx := &wire.MsgTx{
+		TxIn:  []*wire.TxIn{{}},
+		TxOut: []*wire.TxOut{utxOut},
+	}
+	addUtxo(t, w, incomingTx)
+
+	info, err := w.FetchDerivationInfo(utxOut.PkScript)
+	require.NoError(t, err)
+
+	require.Len(t, info.Bip32Path, 5)
+	require.Equal(t, waddrmgr.KeyScopeBIP0084.Purpose+
+		hdkeychain.HardenedKeyStart, info.Bip32Path[0])
+	require.Equal(t, waddrmgr.KeyScopeBIP0084.Coin+
+		hdkeychain.HardenedKeyStart, info.Bip32Path[1])
+	require.EqualValues(t, hdkeychain.HardenedKeyStart, info.Bip32Path[2])
+	require.Equal(t, uint32(0), info.Bip32Path[3])
+	require.Equal(t, uint32(0), info.Bip32Path[4])
+}