chanfunding: use util functions from psbt package

lnwallet/chanfunding/psbt_assembler.go

@@ -1,7 +1,6 @@
 package chanfunding
 
 import (
-	"bytes"
 	"crypto/sha256"
 	"errors"
 	"fmt"
@@ -226,7 +225,7 @@ func (i *PsbtIntent) Verify(packet *psbt.Packet) error {
 	outputSum := int64(0)
 	for _, out := range packet.UnsignedTx.TxOut {
 		outputSum += out.Value
-		if txOutsEqual(out, expectedOutput) {
+		if psbt.TxOutsEqual(out, expectedOutput) {
 			outputFound = true
 		}
 	}
@@ -241,7 +240,7 @@ func (i *PsbtIntent) Verify(packet *psbt.Packet) error {
 	if len(packet.UnsignedTx.TxIn) == 0 {
 		return fmt.Errorf("PSBT has no inputs")
 	}
-	sum, err := sumUtxoInputValues(packet)
+	sum, err := psbt.SumUtxoInputValues(packet)
 	if err != nil {
 		return fmt.Errorf("error determining input sum: %v", err)
 	}
@@ -305,11 +304,13 @@ func (i *PsbtIntent) FinalizeRawTX(rawTx *wire.MsgTx) error {
 	if i.PendingPsbt == nil {
 		return fmt.Errorf("PSBT was not verified first")
 	}
-	err := verifyOutputsEqual(rawTx.TxOut, i.PendingPsbt.UnsignedTx.TxOut)
+	err := psbt.VerifyOutputsEqual(
+		rawTx.TxOut, i.PendingPsbt.UnsignedTx.TxOut,
+	)
 	if err != nil {
 		return fmt.Errorf("outputs differ from verified PSBT: %v", err)
 	}
-	err = verifyInputPrevOutpointsEqual(
+	err = psbt.VerifyInputPrevOutpointsEqual(
 		rawTx.TxIn, i.PendingPsbt.UnsignedTx.TxIn,
 	)
 	if err != nil {
@@ -472,82 +473,6 @@ func (p *PsbtAssembler) ShouldPublishFundingTx() bool {
 // ConditionalPublishAssembler interface.
 var _ ConditionalPublishAssembler = (*PsbtAssembler)(nil)
 
-// sumUtxoInputValues tries to extract the sum of all inputs specified in the
-// UTXO fields of the PSBT. An error is returned if an input is specified that
-// does not contain any UTXO information.
-func sumUtxoInputValues(packet *psbt.Packet) (int64, error) {
-	// We take the TX ins of the unsigned TX as the truth for how many
-	// inputs there should be, as the fields in the extra data part of the
-	// PSBT can be empty.
-	if len(packet.UnsignedTx.TxIn) != len(packet.Inputs) {
-		return 0, fmt.Errorf("TX input length doesn't match PSBT " +
-			"input length")
-	}
-	inputSum := int64(0)
-	for idx, in := range packet.Inputs {
-		switch {
-		case in.WitnessUtxo != nil:
-			// Witness UTXOs only need to reference the TxOut.
-			inputSum += in.WitnessUtxo.Value
-
-		case in.NonWitnessUtxo != nil:
-			// Non-witness UTXOs reference to the whole transaction
-			// the UTXO resides in.
-			utxOuts := in.NonWitnessUtxo.TxOut
-			txIn := packet.UnsignedTx.TxIn[idx]
-			inputSum += utxOuts[txIn.PreviousOutPoint.Index].Value
-
-		default:
-			return 0, fmt.Errorf("input %d has no UTXO information",
-				idx)
-		}
-	}
-	return inputSum, nil
-}
-
-// txOutsEqual returns true if two transaction outputs are equal.
-func txOutsEqual(out1, out2 *wire.TxOut) bool {
-	if out1 == nil || out2 == nil {
-		return out1 == out2
-	}
-	return out1.Value == out2.Value &&
-		bytes.Equal(out1.PkScript, out2.PkScript)
-}
-
-// verifyOutputsEqual verifies that the two slices of transaction outputs are
-// deep equal to each other. We do the length check and manual loop to provide
-// better error messages to the user than just returning "not equal".
-func verifyOutputsEqual(outs1, outs2 []*wire.TxOut) error {
-	if len(outs1) != len(outs2) {
-		return fmt.Errorf("number of outputs are different")
-	}
-	for idx, out := range outs1 {
-		// There is a byte slice in the output so we can't use the
-		// equality operator.
-		if !txOutsEqual(out, outs2[idx]) {
-			return fmt.Errorf("output %d is different", idx)
-		}
-	}
-	return nil
-}
-
-// verifyInputPrevOutpointsEqual verifies that the previous outpoints of the
-// two slices of transaction inputs are deep equal to each other. We do the
-// length check and manual loop to provide better error messages to the user
-// than just returning "not equal".
-func verifyInputPrevOutpointsEqual(ins1, ins2 []*wire.TxIn) error {
-	if len(ins1) != len(ins2) {
-		return fmt.Errorf("number of inputs are different")
-	}
-	for idx, in := range ins1 {
-		if in.PreviousOutPoint != ins2[idx].PreviousOutPoint {
-			return fmt.Errorf("previous outpoint of input %d is "+
-				"different", idx)
-		}
-	}
-	return nil
-}
-
 // verifyInputsSigned verifies that the given list of inputs is non-empty and
 // that all the inputs either contain a script signature or a witness stack.
 func verifyInputsSigned(ins []*wire.TxIn) error {