more script data extraction improvements.

lib/bcoin/script.js

@@ -909,7 +909,7 @@ script.execute = function execute(data, stack, tx, index, flags, recurse) {
         val = stack.pop();
 
         if (flags.verifynulldummy !== false) {
-          if (!Array.isArray(val) || val.length > 0)
+          if (!script.isDummy(val))
             return false;
         }
 
@@ -1170,6 +1170,15 @@ script.createMultisig = function createMultisig(keys, m, n) {
   );
 };
 
+script.createScripthash = function createScripthash(s) {
+  assert(Array.isArray(s));
+  return [
+    'hash160',
+    utils.ripesha(script.encode(s)),
+    'equal'
+  ];
+};
+
 script.redeem = function redeem(s) {
   if (!Array.isArray(s[s.length - 1]))
     return;
@@ -1249,13 +1258,13 @@ script.spendable = function spendable(s, lockTime) {
 };
 
 script.getInputData = function getData(s, prev) {
-  var output;
+  var output, type;
 
   if (prev && !script.isScripthash(prev)) {
     output = script.getOutputData(prev);
     output.side = 'input';
 
-    // We could call getInputData, but
+    // We could call _getInputData, but
     // we really only need the signatures.
     if (output.type === 'pubkey') {
       output.signatures = [s[0]];
@@ -1264,6 +1273,11 @@ script.getInputData = function getData(s, prev) {
       output.keys = [s[1]];
     } else if (output.type === 'multisig') {
       output.signatures = s.slice(1);
+    } else if (output.type === 'scripthash') {
+      // Scripthash is the only case where
+      // we get more data from the input
+      // than the output.
+      output = script._getInputData(s, output.type);
     } else {
       output.signatures = script.getUnknownData(s).signatures;
     }
@@ -1271,13 +1285,24 @@ script.getInputData = function getData(s, prev) {
     return output;
   }
 
-  return script._getInputData(s);
+  if (script.isPubkeyInput(s))
+    type = 'pubkey';
+  else if (script.isPubkeyhashInput(s))
+    type = 'pubkeyhash';
+  else if (script.isMultisigInput(s))
+    type = 'multisig';
+  else if (script.isScripthashInput(s))
+    type = 'scripthash';
+
+  return script._getInputData(s, type);
 };
 
-script._getInputData = function _getInputData(s) {
+script._getInputData = function _getInputData(s, type) {
   var sig, key, hash, raw, redeem, lock, hash, address, input, output;
 
-  if (script.isPubkeyInput(s)) {
+  assert(typeof type === 'string');
+
+  if (type === 'pubkey') {
     sig = s[0];
     return {
       type: 'pubkey',
@@ -1287,7 +1312,7 @@ script._getInputData = function _getInputData(s) {
     };
   }
 
-  if (script.isPubkeyhashInput(s)) {
+  if (type === 'pubkeyhash') {
     sig = s[0];
     key = s[1];
     hash = bcoin.wallet.key2hash(key);
@@ -1302,7 +1327,7 @@ script._getInputData = function _getInputData(s) {
     };
   }
 
-  if (script.isMultisigInput(s)) {
+  if (type === 'multisig') {
     sig = s.slice(1);
     return {
       type: 'multisig',
@@ -1313,15 +1338,15 @@ script._getInputData = function _getInputData(s) {
     };
   }
 
-  if (script.isScripthashInput(s)) {
+  if (type === 'scripthash') {
     raw = s[s.length - 1];
     redeem = script.decode(raw);
     lock = script.lockTime(redeem);
     hash = bcoin.wallet.key2hash(raw);
     address = bcoin.wallet.hash2addr(hash, 'scripthash');
-    input = script.getInputData(s.slice(0, -1));
-    delete input.none;
     output = script.getOutputData(script.subscript(redeem));
+    input = script._getInputData(s.slice(0, -1), output.type);
+    delete input.none;
     return utils.merge(input, output, {
       type: 'scripthash',
       side: 'input',
@@ -1620,8 +1645,10 @@ script.isPubkeyhashInput = function isPubkeyhashInput(s, key) {
 script.isMultisigInput = function isMultisigInput(s, keys, tx, i) {
   var i, o;
 
-  // We need to rule out scripthash
+  // We need to rule out scripthash because
-  // because it may look like multisig
+  // it may look like multisig. This is
+  // strange because it's technically a
+  // recursive call.
   if (script.isScripthashInput(s))
     return false;
 
@@ -1664,7 +1691,7 @@ script.isMultisigInput = function isMultisigInput(s, keys, tx, i) {
   };
 };
 
-script.isScripthashInput = function isScripthashInput(s, data) {
+script.isScripthashInput = function isScripthashInput(s, data, strict) {
   var raw, redeem;
 
   // Grab the raw redeem script.
@@ -1680,6 +1707,25 @@ script.isScripthashInput = function isScripthashInput(s, data) {
   if (!Array.isArray(raw))
     return false;
 
+  // If the last data element is a valid
+  // signature or key, it's _extremely_
+  // unlikely this is a scripthash.
+  if (script.isSignatureEncoding(raw))
+    return false;
+
+  if (script.isKeyEncoding(raw))
+    return false;
+
+  // Check data against last array in case
+  // a raw redeem script was passed in.
+  if (data && utils.isEqual(data, raw))
+    return raw;
+
+  // Return here if we do not want to check
+  // against standard transaction types.
+  if (!strict)
+    return raw;
+
   // P2SH redeem scripts can be nonstandard: make
   // it easier for other functions to parse this.
   redeem = script.subscript(script.decode(raw));
@@ -1694,11 +1740,6 @@ script.isScripthashInput = function isScripthashInput(s, data) {
     return false;
   }
 
-  // Check data against last array in case
-  // a raw redeem script was passed in.
-  if (data && utils.isEqual(data, raw))
-    return raw;
-
   // Test against all other script types
   if (!script.isPubkey(redeem, data)
     && !script.isPubkeyhash(redeem, data)
@@ -1840,7 +1881,7 @@ script.isSignature = function isSignature(sig) {
   return sig.length >= 9 && sig.length <= 73;
 };
 
-script.isEmpty = function isEmpty(data) {
+script.isDummy = function isDummy(data) {
   if (!utils.isBuffer(data))
     return false;
 

lib/bcoin/tx.js

@@ -423,7 +423,7 @@ TX.prototype.signInput = function signInput(index, key, type) {
   // and increment the total number of
   // signatures.
   if (ki < len && signatures < m) {
-    if (bcoin.script.isEmpty(input.script[ki])) {
+    if (bcoin.script.isDummy(input.script[ki])) {
       input.script[ki] = signature;
       signatures++;
     }
@@ -433,7 +433,7 @@ TX.prototype.signInput = function signInput(index, key, type) {
   if (signatures >= m) {
     // Remove empty slots left over.
     for (i = len - 1; i >= 1; i--) {
-      if (bcoin.script.isEmpty(input.script[i])) {
+      if (bcoin.script.isDummy(input.script[i])) {
         input.script.splice(i, 1);
         len--;
       }