move some script logic from Address to Script

lib/address.js

@@ -244,28 +244,11 @@ Address._transformPublicKey = function(pubkey) {
  * @private
  */
 Address._transformScript = function(script, network) {
-  var info = {};
-  if (!(script instanceof Script)) {
-    throw new TypeError('script must be an instance of Script.');
-  }
-  if (script.isScriptHashOut()) {
-    info.hashBuffer = script.getData();
-    info.type = Address.PayToScriptHash;
-  } else if (script.isPublicKeyHashOut()) {
-    info.hashBuffer = script.getData();
-    info.type = Address.PayToPublicKeyHash;
-  } else if (script.isPublicKeyHashIn()) {
-    // hash the publickey found in the scriptSig
-    info.hashBuffer = Hash.sha256ripemd160(script.chunks[1].buf);
-    info.type = Address.PayToPublicKeyHash;
-  } else if (script.isScriptHashIn()) {
-    // hash the redeemscript found at the end of the scriptSig
-    info.hashBuffer = Hash.sha256ripemd160(script.chunks[script.chunks.length - 1].buf);
-    info.type = Address.PayToScriptHash;
-  } else {
+  $.checkArgument(script instanceof Script, 'script must be a Script instance');
+  var info = script.getAddressInfo(network);
+  if (!info) {
     throw new errors.Script.CantDeriveAddress(script);
   }
-  info.network = Networks.get(network) || Networks.defaultNetwork;
   return info;
 };
 
@@ -297,7 +280,7 @@ Address.createMultisig = function(publicKeys, threshold, network) {
  */
 Address._transformString = function(data, network, type) {
   if (typeof(data) !== 'string') {
-    throw new TypeError('Address supplied is not a string.');
+    throw new TypeError('data parameter supplied is not a string.');
   }
   var addressBuffer = Base58Check.decode(data);
   var info = Address._transformBuffer(addressBuffer, network, type);
@@ -372,6 +355,7 @@ Address.payingTo = function(script, network) {
  * @returns {Address} A new valid and frozen instance of an Address
  */
 Address.fromScript = function(script, network) {
+  $.checkArgument(script instanceof Script, 'script must be a Script instance');
   var info = Address._transformScript(script, network);
   return new Address(info.hashBuffer, network, info.type);
 };

lib/script/script.js

@@ -730,6 +730,33 @@ Script.fromAddress = function(address) {
   throw new errors.Script.UnrecognizedAddress(address);
 };
 
+/**
+ * @param {Network=} network
+ * @return {Address|boolean} the associated address information object
+ * for this script if any, or false
+ */
+Script.prototype.getAddressInfo = function() {
+  var Address = require('../address');
+  var info = {};
+  if (this.isScriptHashOut()) {
+    info.hashBuffer = this.getData();
+    info.type = Address.PayToScriptHash;
+  } else if (this.isPublicKeyHashOut()) {
+    info.hashBuffer = this.getData();
+    info.type = Address.PayToPublicKeyHash;
+  } else if (this.isPublicKeyHashIn()) {
+    // hash the publickey found in the scriptSig
+    info.hashBuffer = Hash.sha256ripemd160(this.chunks[1].buf);
+    info.type = Address.PayToPublicKeyHash;
+  } else if (this.isScriptHashIn()) {
+    // hash the redeemscript found at the end of the scriptSig
+    info.hashBuffer = Hash.sha256ripemd160(this.chunks[this.chunks.length - 1].buf);
+    info.type = Address.PayToScriptHash;
+  } else {
+    return false;
+  }
+  return info;
+};
 /**
  * @param {Network=} network
  * @return {Address|boolean} the associated address for this script if possible, or false
@@ -737,14 +764,12 @@ Script.fromAddress = function(address) {
 Script.prototype.toAddress = function(network) {
   var Address = require('../address');
   network = Networks.get(network) || this._network || Networks.defaultNetwork;
-  var canConvertToAddress = this.isPublicKeyHashOut() ||
-    this.isScriptHashOut() ||
-    this.isPublicKeyHashIn() ||
-    this.isScriptHashIn();
-  if (canConvertToAddress) {
-    return new Address(this, network);
-  }
-  return false;
+  var info = this.getAddressInfo();
+  if (!info) {
+    return false;
+  }
+  info.network = Networks.get(network) || Networks.defaultNetwork;
+  return new Address(info);
 };
 
 /**

test/address.js

@@ -280,13 +280,13 @@ describe('Address', function() {
     it('should error because of incorrect type for script transform', function() {
       (function() {
         return Address._transformScript(new Buffer(20));
-      }).should.throw('script must be an instance of Script.');
+      }).should.throw('Invalid Argument: script must be a Script instance');
     });
 
     it('should error because of incorrect type for string transform', function() {
       (function() {
         return Address._transformString(new Buffer(20));
-      }).should.throw('Address supplied is not a string.');
+      }).should.throw('data parameter supplied is not a string.');
     });
 
     it('should make an address from a pubkey hash buffer', function() {