From 95b4a2806d6d433bd0d766d0be7c0183d28541cd Mon Sep 17 00:00:00 2001
From: Luke Childs <lukechilds123@gmail.com>
Date: Fri, 28 Jun 2019 18:21:32 +0700
Subject: [PATCH] Improve code re-use for redeem script checks

---
 src/psbt.js    | 37 +++++++++++++++++--------------------
 ts_src/psbt.ts | 46 +++++++++++++++++++++++-----------------------
 2 files changed, 40 insertions(+), 43 deletions(-)

diff --git a/src/psbt.js b/src/psbt.js
index 4dc72ff..c68afb0 100644
--- a/src/psbt.js
+++ b/src/psbt.js
@@ -3,6 +3,17 @@ Object.defineProperty(exports, '__esModule', { value: true });
 const bip174_1 = require('bip174');
 const payments = require('./payments');
 const transaction_1 = require('./transaction');
+const checkRedeemScript = (inputIndex, scriptPubKey, redeemScript) => {
+  const redeemScriptOutput = payments.p2sh({
+    redeem: { output: redeemScript },
+  }).output;
+  // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
+  if (Buffer.compare(scriptPubKey, redeemScriptOutput) !== 0) {
+    throw new Error(
+      `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
+    );
+  }
+};
 class Psbt extends bip174_1.Psbt {
   constructor() {
     super();
@@ -51,29 +62,15 @@ class Psbt extends bip174_1.Psbt {
       if (input.redeemScript) {
         const prevoutIndex = unsignedTx.ins[inputIndex].index;
         const prevout = nonWitnessUtxoTx.outs[prevoutIndex];
-        const redeemScriptOutput = payments.p2sh({
-          redeem: { output: input.redeemScript },
-        }).output;
-        // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
-        if (Buffer.compare(prevout.script, redeemScriptOutput) !== 0) {
-          throw new Error(
-            `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
-          );
-        }
+        checkRedeemScript(inputIndex, prevout.script, input.redeemScript);
       }
     } else if (input.witnessUtxo) {
       if (input.redeemScript) {
-        const redeemScriptOutput = payments.p2sh({
-          redeem: { output: input.redeemScript },
-        }).output;
-        // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
-        if (
-          Buffer.compare(input.witnessUtxo.script, redeemScriptOutput) !== 0
-        ) {
-          throw new Error(
-            `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
-          );
-        }
+        checkRedeemScript(
+          inputIndex,
+          input.witnessUtxo.script,
+          input.redeemScript,
+        );
       }
     }
     // TODO: Get hash to sign
diff --git a/ts_src/psbt.ts b/ts_src/psbt.ts
index ab1fd7b..70e04c9 100644
--- a/ts_src/psbt.ts
+++ b/ts_src/psbt.ts
@@ -3,6 +3,23 @@ import { Signer } from './ecpair';
 import * as payments from './payments';
 import { Transaction } from './transaction';
 
+const checkRedeemScript = (
+  inputIndex: number,
+  scriptPubKey: Buffer,
+  redeemScript: Buffer,
+): void => {
+  const redeemScriptOutput = payments.p2sh({
+    redeem: { output: redeemScript },
+  }).output as Buffer;
+
+  // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
+  if (Buffer.compare(scriptPubKey, redeemScriptOutput) !== 0) {
+    throw new Error(
+      `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
+    );
+  }
+};
+
 export class Psbt extends PsbtBase {
   constructor() {
     super();
@@ -53,32 +70,15 @@ export class Psbt extends PsbtBase {
       if (input.redeemScript) {
         const prevoutIndex = unsignedTx.ins[inputIndex].index;
         const prevout = nonWitnessUtxoTx.outs[prevoutIndex];
-
-        const redeemScriptOutput = payments.p2sh({
-          redeem: { output: input.redeemScript },
-        }).output as Buffer;
-
-        // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
-        if (Buffer.compare(prevout.script, redeemScriptOutput) !== 0) {
-          throw new Error(
-            `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
-          );
-        }
+        checkRedeemScript(inputIndex, prevout.script, input.redeemScript);
       }
     } else if (input.witnessUtxo) {
       if (input.redeemScript) {
-        const redeemScriptOutput = payments.p2sh({
-          redeem: { output: input.redeemScript },
-        }).output as Buffer;
-
-        // If a redeemScript is provided, the scriptPubKey must be for that redeemScript
-        if (
-          Buffer.compare(input.witnessUtxo.script, redeemScriptOutput) !== 0
-        ) {
-          throw new Error(
-            `Redeem script for input #${inputIndex} doesn't match the scriptPubKey in the prevout`,
-          );
-        }
+        checkRedeemScript(
+          inputIndex,
+          input.witnessUtxo.script,
+          input.redeemScript,
+        );
       }
     }