From 8d6f5621816b92d9c5f5dbed3c28b04b4e594ae4 Mon Sep 17 00:00:00 2001
From: Andreas Schildbach <andreas.schildbach@bloq.com>
Date: Wed, 30 Jan 2019 02:25:08 +0100
Subject: [PATCH] ScriptBuilder: Add createP2WSHOutputScript() helpers.

---
 .../java/org/bitcoinj/script/ScriptBuilder.java | 17 +++++++++++++++++
 .../org/bitcoinj/script/ScriptPatternTest.java  |  9 ++-------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/core/src/main/java/org/bitcoinj/script/ScriptBuilder.java b/core/src/main/java/org/bitcoinj/script/ScriptBuilder.java
index eee6a497..733b2924 100644
--- a/core/src/main/java/org/bitcoinj/script/ScriptBuilder.java
+++ b/core/src/main/java/org/bitcoinj/script/ScriptBuilder.java
@@ -23,6 +23,7 @@ import org.bitcoinj.core.Address;
 import org.bitcoinj.core.LegacyAddress;
 import org.bitcoinj.core.ECKey;
 import org.bitcoinj.core.SegwitAddress;
+import org.bitcoinj.core.Sha256Hash;
 import org.bitcoinj.core.Transaction;
 import org.bitcoinj.core.Utils;
 import org.bitcoinj.crypto.TransactionSignature;
@@ -485,6 +486,22 @@ public class ScriptBuilder {
         return ScriptBuilder.createP2SHOutputScript(hash);
     }
 
+    /**
+     * Creates a segwit scriptPubKey that sends to the given script hash.
+     */
+    public static Script createP2WSHOutputScript(byte[] hash) {
+        checkArgument(hash.length == SegwitAddress.WITNESS_PROGRAM_LENGTH_SH);
+        return new ScriptBuilder().smallNum(0).data(hash).build();
+    }
+
+    /**
+     * Creates a segwit scriptPubKey for the given redeem script.
+     */
+    public static Script createP2WSHOutputScript(Script redeemScript) {
+        byte[] hash = Sha256Hash.hash(redeemScript.getProgram());
+        return ScriptBuilder.createP2WSHOutputScript(hash);
+    }
+
     /**
      * Creates a P2SH output script with given public keys and threshold. Given public keys will be placed in
      * redeem script in the lexicographical sorting order.
diff --git a/core/src/test/java/org/bitcoinj/script/ScriptPatternTest.java b/core/src/test/java/org/bitcoinj/script/ScriptPatternTest.java
index 70c5868a..c78208e6 100644
--- a/core/src/test/java/org/bitcoinj/script/ScriptPatternTest.java
+++ b/core/src/test/java/org/bitcoinj/script/ScriptPatternTest.java
@@ -19,11 +19,7 @@ package org.bitcoinj.script;
 
 import com.google.common.collect.Lists;
 
-import org.bitcoinj.core.NetworkParameters;
-import org.bitcoinj.core.SegwitAddress;
-import org.bitcoinj.core.Sha256Hash;
 import org.bitcoinj.core.ECKey;
-import org.bitcoinj.params.MainNetParams;
 import org.junit.Test;
 
 import java.math.BigInteger;
@@ -33,7 +29,6 @@ import static org.junit.Assert.assertTrue;
 
 public class ScriptPatternTest {
     private List<ECKey> keys = Lists.newArrayList(new ECKey(), new ECKey(), new ECKey());
-    private static final NetworkParameters MAINNET = MainNetParams.get();
 
     @Test
     public void testCommonScripts() {
@@ -47,10 +42,10 @@ public class ScriptPatternTest {
                 ScriptBuilder.createOutputScript(keys.get(0))
         ));
         assertTrue(ScriptPattern.isPayToWitnessPubKeyHash(
-                ScriptBuilder.createOutputScript(SegwitAddress.fromHash(MAINNET, keys.get(0).getPubKeyHash()))
+                ScriptBuilder.createP2WPKHOutputScript(keys.get(0))
         ));
         assertTrue(ScriptPattern.isPayToWitnessScriptHash(
-                ScriptBuilder.createOutputScript(SegwitAddress.fromHash(MAINNET, Sha256Hash.hash(new byte[0])))
+                ScriptBuilder.createP2WSHOutputScript(new ScriptBuilder().build())
         ));
         assertTrue(ScriptPattern.isSentToMultisig(
                 ScriptBuilder.createMultiSigOutputScript(2, keys)