From 6c0745adce6d21bac0feea87eef46862ee32457e Mon Sep 17 00:00:00 2001
From: Daniel Cousens <github@dcousens.com>
Date: Thu, 26 Nov 2015 12:40:06 +1100
Subject: [PATCH] TxBuilder: add setLockTime

---
 src/transaction_builder.js             | 17 +++++++++++++++++
 test/fixtures/transaction_builder.json | 22 ++++++++++++++++++++++
 test/transaction_builder.js            |  4 ++--
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/src/transaction_builder.js b/src/transaction_builder.js
index 73fd12b..64069f2 100644
--- a/src/transaction_builder.js
+++ b/src/transaction_builder.js
@@ -4,6 +4,8 @@ var bscript = require('./script')
 var bufferEquals = require('buffer-equals')
 var networks = require('./networks')
 var ops = require('./opcodes')
+var typeforce = require('typeforce')
+var types = require('./types')
 
 var ECPair = require('./ecpair')
 var ECSignature = require('./ecsignature')
@@ -135,6 +137,21 @@ function TransactionBuilder (network) {
   this.tx = new Transaction()
 }
 
+TransactionBuilder.prototype.setLockTime = function (locktime) {
+  typeforce(types.UInt32, locktime)
+
+  // if any signatures exist, throw
+  if (this.inputs.some(function (input) {
+    if (!input.signatures) return false
+
+    return input.signatures.some(function (s) { return s })
+  })) {
+    throw new Error('No, this would invalidate signatures')
+  }
+
+  this.tx.locktime = locktime
+}
+
 TransactionBuilder.fromTransaction = function (transaction, network) {
   var txb = new TransactionBuilder(network)
 
diff --git a/test/fixtures/transaction_builder.json b/test/fixtures/transaction_builder.json
index 2ccda67..f17ceca 100644
--- a/test/fixtures/transaction_builder.json
+++ b/test/fixtures/transaction_builder.json
@@ -263,6 +263,28 @@
             "value": 10000
           }
         ]
+      },
+      {
+        "description": "Transaction w/ nLockTime, pubKeyHash -> pubKeyHash",
+        "txHex": "0100000001ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff000000006b483045022100a3b254e1c10b5d039f36c05f323995d6e5a367d98dd78a13d5bbc3991b35720e022022fccea3897d594de0689601fbd486588d5bfa6915be2386db0397ee9a6e80b601210279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798ffffffff0110270000000000001976a914aa4d7985c57e011a8b3dd8e0e5a73aaef41629c588acffff0000",
+        "locktime": 65535,
+        "inputs": [
+          {
+            "txId": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+            "vout": 0,
+            "signs": [
+              {
+                "keyPair": "KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn"
+              }
+            ]
+          }
+        ],
+        "outputs": [
+          {
+            "script": "OP_DUP OP_HASH160 aa4d7985c57e011a8b3dd8e0e5a73aaef41629c5 OP_EQUALVERIFY OP_CHECKSIG",
+            "value": 10000
+          }
+        ]
       }
     ],
     "fromTransaction": [
diff --git a/test/transaction_builder.js b/test/transaction_builder.js
index 5720d62..b6d2896 100644
--- a/test/transaction_builder.js
+++ b/test/transaction_builder.js
@@ -17,13 +17,13 @@ function construct (f, sign) {
   var network = NETWORKS[f.network]
   var txb = new TransactionBuilder(network)
 
-  // FIXME: add support for locktime/version in TransactionBuilder API
+  // FIXME: add support for version in TransactionBuilder API
   if (f.version !== undefined) {
     txb.tx.version = f.version
   }
 
   if (f.locktime !== undefined) {
-    txb.tx.locktime = f.locktime
+    txb.setLockTime(f.locktime)
   }
 
   f.inputs.forEach(function (input) {