From 0f73c3f7a38a04c3865a3c6fbf5689771cce168a Mon Sep 17 00:00:00 2001
From: Esteban Ordano <eordano@gmail.com>
Date: Thu, 8 Jan 2015 16:38:43 -0300
Subject: [PATCH] Throw error if dust amount is detected

---
 .jshintrc                       |  2 +-
 lib/errors/spec.js              |  3 +++
 lib/transaction/transaction.js  | 15 +++++++++++++++
 test/transaction/deserialize.js |  4 ++--
 test/transaction/transaction.js | 10 ++++++++++
 5 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/.jshintrc b/.jshintrc
index 1d70b69..40fd8c6 100644
--- a/.jshintrc
+++ b/.jshintrc
@@ -28,7 +28,7 @@
     "maxcomplexity": 6,   // Cyclomatic complexity (http://en.wikipedia.org/wiki/Cyclomatic_complexity)
     "maxdepth": 4,        // Maximum depth of nested control structures
     "maxlen": 120,        // Maximum number of cols in a line
-    "multistr": true      // Allow use of multiline EOL escaping
+    "multistr": true,     // Allow use of multiline EOL escaping
 
     "predef": [ // Extra globals.
         "after",
diff --git a/lib/errors/spec.js b/lib/errors/spec.js
index a3e42bc..70fbeac 100644
--- a/lib/errors/spec.js
+++ b/lib/errors/spec.js
@@ -61,6 +61,9 @@ module.exports = [{
       }, {
         name: 'UnableToVerifySignature',
         message: format('Unable to verify signature: {0}')
+      }, {
+        name: 'DustOutputs',
+        message: format('Dust amount detected in one output')
       }, {
         name: 'FeeError',
         message: format('Fees are not correctly set {0}'),
diff --git a/lib/transaction/transaction.js b/lib/transaction/transaction.js
index a76f396..54ac4bc 100644
--- a/lib/transaction/transaction.js
+++ b/lib/transaction/transaction.js
@@ -126,6 +126,9 @@ Transaction.prototype.checkedSerialize = Transaction.prototype.toString = functi
       throw new errors.Transaction.FeeError(feeError);
     }
   }
+  if (this._hasDustOutputs()) {
+    throw new errors.Transaction.DustOutputs();
+  }
   return this.uncheckedSerialize();
 };
 
@@ -143,6 +146,18 @@ Transaction.prototype._validateChange = function() {
   }
 };
 
+Transaction.DUST_AMOUNT = 5460;
+
+Transaction.prototype._hasDustOutputs = function() {
+  var output;
+  for (output in this.outputs) {
+    if (this.outputs[output].satoshis < Transaction.DUST_AMOUNT) {
+      return true;
+    }
+  }
+  return false;
+};
+
 Transaction.prototype.inspect = function() {
   return '<Transaction: ' + this.toString() + '>';
 };
diff --git a/test/transaction/deserialize.js b/test/transaction/deserialize.js
index 499a151..28993d9 100644
--- a/test/transaction/deserialize.js
+++ b/test/transaction/deserialize.js
@@ -12,7 +12,7 @@ describe('Transaction deserialization', function() {
     vectors_valid.forEach(function(vector) {
       if (vector.length > 1) {
         var hexa = vector[1];
-        Transaction(hexa).serialize().should.equal(hexa);
+        Transaction(hexa).serialize(true).should.equal(hexa);
         index++;
       }
     });
@@ -22,7 +22,7 @@ describe('Transaction deserialization', function() {
     vectors_invalid.forEach(function(vector) {
       if (vector.length > 1) {
         var hexa = vector[1];
-        Transaction(hexa).serialize().should.equal(hexa);
+        Transaction(hexa).serialize(true).should.equal(hexa);
         index++;
       }
     });
diff --git a/test/transaction/transaction.js b/test/transaction/transaction.js
index 2a36acf..c42ae24 100644
--- a/test/transaction/transaction.js
+++ b/test/transaction/transaction.js
@@ -242,6 +242,16 @@ describe('Transaction', function() {
         return transaction.serialize();
       }).to.throw(errors.Transaction.FeeError);
     });
+    it('fails if a dust transaction is created', function() {
+      var transaction = new Transaction()
+        .from(simpleUtxoWith1BTC)
+        .to(toAddress, 1)
+        .change(changeAddress)
+        .sign(privateKey);
+      expect(function() {
+        return transaction.serialize();
+      }).to.throw(errors.Transaction.DustOutputs);
+    });
   });
 });