From 141dbcb65efc1eecedce0c61716f52974ac83dde Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Tue, 5 Apr 2016 02:58:53 -0700
Subject: [PATCH] cleanup

---
 lib/bcoin/mtx.js | 58 ++++++++++++++++++------------------------------
 1 file changed, 22 insertions(+), 36 deletions(-)

diff --git a/lib/bcoin/mtx.js b/lib/bcoin/mtx.js
index c310682a..5c7602d0 100644
--- a/lib/bcoin/mtx.js
+++ b/lib/bcoin/mtx.js
@@ -191,18 +191,16 @@ MTX.prototype.scriptInput = function scriptInput(index, addr) {
       redeemScript = addr.program.encode();
       vector = input.witness.items;
       dummy = new Buffer([]);
-      assert(addr.program.code[0] === opcodes.OP_0,
-        'Non-zero version passed to address.');
-      if (addr.program.code[1].length === 32) {
+      if (addr.program.isWitnessScripthash()) {
         // P2WSH nested within pay-to-scripthash
         // (it had to be this complicated, didn't it?)
         witnessScript = addr.script.encode();
         prev = addr.script;
-      } else if (addr.program.code[1].length === 20) {
+      } else if (addr.program.isWitnessPubkeyhash()) {
         // P2WPKH nested within pay-to-scripthash.
         prev = Script.createPubkeyhash(addr.keyHash);
       } else {
-        assert(false, 'Unknown program data length passed to address.');
+        assert(false, 'Unknown program.');
       }
     } else if (addr.script && utils.isEqual(prev.code[1], addr.scriptHash160)) {
       // Regular P2SH.
@@ -218,17 +216,14 @@ MTX.prototype.scriptInput = function scriptInput(index, addr) {
     vector = input.witness.items;
     dummy = new Buffer([]);
 
-    if (prev.code[0] !== opcodes.OP_0)
-      return false;
-
-    if (prev.code[1].length === 32) {
+    if (prev.isWitnessScripthash()) {
       // Bare P2WSH.
       if (!addr.script || !utils.isEqual(prev.code[1], addr.scriptHash256))
         return false;
 
       witnessScript = addr.script.encode();
       prev = addr.script;
-    } else if (prev.code[1].length === 20) {
+    } else if (prev.isWitnessPubkeyhash()) {
       // Bare P2WPKH.
       if (!utils.isEqual(prev.code[1], addr.keyHash))
         return false;
@@ -320,7 +315,7 @@ MTX.prototype.scriptInput = function scriptInput(index, addr) {
 };
 
 MTX.prototype.createSignature = function createSignature(index, prev, key, type, version) {
-  var hash, signature;
+  var hash;
 
   if (typeof index !== 'number')
     index = this.inputs.indexOf(index);
@@ -336,16 +331,11 @@ MTX.prototype.createSignature = function createSignature(index, prev, key, type,
   hash = this.signatureHash(index, prev, type, version);
 
   // Sign the transaction with our one input
-  signature = Script.sign(hash, key, type);
-
-  // Something is broken if this doesn't work:
-  // assert(Script.checksig(hash, signature, key), 'BUG: Verify failed.');
-
-  return signature;
+  return Script.sign(hash, key, type);
 };
 
 MTX.prototype.signInput = function signInput(index, addr, type) {
-  var input, prev, signature, ki, signatures, i;
+  var input, prev, signature, index, signatures, i;
   var len, m, n, keys, vector, dummy, version;
 
   assert(this.ts === 0, 'Cannot modify a confirmed tx.');
@@ -360,7 +350,7 @@ MTX.prototype.signInput = function signInput(index, addr, type) {
   // We should have previous outputs by now.
   assert(input.coin);
 
-  // Get the previous output's subscript
+  // Get the previous output's script
   prev = input.coin.script;
 
   vector = input.script.code;
@@ -398,10 +388,8 @@ MTX.prototype.signInput = function signInput(index, addr, type) {
   // Create our signature.
   signature = this.createSignature(index, prev, addr.key, type, version);
 
-  // Add signatures.
+  // P2PK
   if (prev.isPubkey()) {
-    // P2PK
-
     // Already signed.
     if (Script.isSignature(vector[0]))
       return true;
@@ -415,9 +403,8 @@ MTX.prototype.signInput = function signInput(index, addr, type) {
     return true;
   }
 
+  // P2PKH
   if (prev.isPubkeyhash()) {
-    // P2PKH
-
     // Already signed.
     if (Script.isSignature(vector[0]))
       return true;
@@ -431,9 +418,8 @@ MTX.prototype.signInput = function signInput(index, addr, type) {
     return true;
   }
 
+  // Multisig
   if (prev.isMultisig()) {
-    // Multisig
-
     // Grab the redeem script's keys to figure
     // out where our key should go.
     keys = prev.code.slice(1, -2);
@@ -488,25 +474,25 @@ MTX.prototype.signInput = function signInput(index, addr, type) {
 
   // Find the key index so we can place
   // the signature in the same index.
-  ki = utils.indexOf(keys, addr.publicKey);
+  index = utils.indexOf(keys, addr.publicKey);
 
   // Our public key is not in the prev_out
   // script. We tried to sign a transaction
   // that is not redeemable by us.
-  if (ki === -1)
+  if (index === -1)
     return false;
 
   // Offset key index by one to turn it into
   // "sig index". Accounts for OP_0 byte at
   // the start.
-  ki++;
+  index++;
 
   // Add our signature to the correct slot
   // and increment the total number of
   // signatures.
-  if (ki < len && signatures < m) {
-    if (Script.isZero(vector[ki])) {
-      vector[ki] = signature;
+  if (index < len && signatures < m) {
+    if (Script.isZero(vector[index])) {
+      vector[index] = signature;
       signatures++;
     }
   }
@@ -532,8 +518,8 @@ MTX.prototype.signInput = function signInput(index, addr, type) {
     }
 
     // Sanity checks.
-    assert.equal(signatures, m);
-    assert.equal(len - 1, m);
+    assert(signatures === m);
+    assert(len - 1 === m);
   }
 
   return signatures === m;
@@ -551,7 +537,7 @@ MTX.prototype.isSigned = function isSigned() {
     if (!input.coin)
       return false;
 
-    // Get the prevout's subscript
+    // Get the prevout's script
     prev = input.coin.script;
 
     // Script length, needed for multisig
@@ -735,7 +721,7 @@ MTX.prototype.maxSize = function maxSize(options, force) {
       continue;
     }
 
-    // Get the previous output's subscript
+    // Get the previous output's script
     prev = input.coin.script;
 
     // If we have access to the redeem script,