Merge pull request #92 from Fi3/feature/merkleblock-add-txsThatMatchFilter

Feature/merkleblock add txs that match filter

Author: matiu

lib/block/merkleblock.js

@@ -8,6 +8,7 @@ var BufferWriter = require('../encoding/bufferwriter');
 var Hash = require('../crypto/hash');
 var JSUtil = require('../util/js');
 var Transaction = require('../transaction');
+var errors = require('../errors');
 var $ = require('../util/preconditions');
 
 /**
@@ -63,6 +64,7 @@ function MerkleBlock(arg) {
   _.extend(this,info);
   this._flagBitsUsed = 0;
   this._hashesUsed = 0;
+
   return this;
 }
 
@@ -149,26 +151,61 @@ MerkleBlock.prototype.validMerkleTree = function validMerkleTree() {
   return BufferUtil.equals(root, this.header.merkleRoot);
 };
 
+/**
+ * Return a list of all the txs hash that match the filter
+ * @returns {Array} - txs hash that match the filter
+ */
+MerkleBlock.prototype.filterdTxsHash = function filterdTxsHash() {
+  $.checkState(_.isArray(this.flags), 'MerkleBlock flags is not an array');
+  $.checkState(_.isArray(this.hashes), 'MerkleBlock hashes is not an array');
+
+  // Can't have more hashes than numTransactions
+  if(this.hashes.length > this.numTransactions) {
+    throw new errors.MerkleBlock.InvalidMerkleTree();
+  }
+
+  // Can't have more flag bits than num hashes
+  if(this.flags.length * 8 < this.hashes.length) {
+    throw new errors.MerkleBlock.InvalidMerkleTree();
+  }
+
+  // If there is only one hash the filter do not match any txs in the block
+  if(this.hashes.length === 1) {
+    return [];
+  };
+
+  var height = this._calcTreeHeight();
+  var opts = { hashesUsed: 0, flagBitsUsed: 0 };
+  var txs = this._traverseMerkleTree(height, 0, opts, true);
+  if(opts.hashesUsed !== this.hashes.length) {
+    throw new errors.MerkleBlock.InvalidMerkleTree();
+  }
+  return txs;
+};
+
 /**
  * Traverse a the tree in this MerkleBlock, validating it along the way
  * Modeled after Bitcoin Core merkleblock.cpp TraverseAndExtract()
  * @param {Number} - depth - Current height
  * @param {Number} - pos - Current position in the tree
  * @param {Object} - opts - Object with values that need to be mutated throughout the traversal
+ * @param {Boolean} - checkForTxs - if true return opts.txs else return the Merkle Hash
  * @param {Number} - opts.flagBitsUsed - Number of flag bits used, should start at 0
  * @param {Number} - opts.hashesUsed - Number of hashes used, should start at 0
- * @param {Array} - opts.txs - Will finish populated by transactions found during traversal
+ * @param {Array} - opts.txs - Will finish populated by transactions found during traversal that match the filter
  * @returns {Buffer|null} - Buffer containing the Merkle Hash for that height
+ * @returns {Array} - transactions found during traversal that match the filter
  * @private
  */
-MerkleBlock.prototype._traverseMerkleTree = function traverseMerkleTree(depth, pos, opts) {
+MerkleBlock.prototype._traverseMerkleTree = function traverseMerkleTree(depth, pos, opts, checkForTxs) {
   /* jshint maxcomplexity:  12*/
   /* jshint maxstatements: 20 */
 
   opts = opts || {};
   opts.txs = opts.txs || [];
   opts.flagBitsUsed = opts.flagBitsUsed || 0;
   opts.hashesUsed = opts.hashesUsed || 0;
+  var checkForTxs = checkForTxs || false;
 
   if(opts.flagBitsUsed > this.flags.length * 8) {
     return null;
@@ -189,7 +226,11 @@ MerkleBlock.prototype._traverseMerkleTree = function traverseMerkleTree(depth, p
     if(pos*2+1 < this._calcTreeWidth(depth-1)) {
       right = this._traverseMerkleTree(depth-1, pos*2+1, opts);
     }
-    return Hash.sha256sha256(new Buffer.concat([left, right]));
+    if (checkForTxs){
+      return opts.txs;
+    } else {
+      return Hash.sha256sha256(new Buffer.concat([left, right]));
+    };
   }
 };
 

lib/errors/spec.js

@@ -44,6 +44,13 @@ module.exports = [{
     'name': 'InvalidRate',
     'message': 'Invalid exchange rate: {0}'
   }]
+}, {
+  name: 'MerkleBlock',
+  message: 'Internal Error on MerkleBlock {0}',
+  errors: [{
+    'name': 'InvalidMerkleTree',
+    'message': 'This MerkleBlock contain an invalid Merkle Tree'
+  }]
 }, {
   name: 'Transaction',
   message: 'Internal Error on Transaction {0}',

test/block/merkleblock.js

@@ -152,6 +152,36 @@ describe('MerkleBlock', function() {
 
   });
 
+  describe('#filterdTxsHash', function() {
+
+    it('should validate good merkleblocks', function() {
+      var hashOfFilteredTx = '6f64fd5aa9dd01f74c03656d376625cf80328d83d9afebe60cc68b8f0e245bd9' 
+      var b = MerkleBlock(data.JSON[3]);
+      b.filterdTxsHash()[0].should.equal(hashOfFilteredTx);
+    });
+
+    it('should fail with merkleblocks with too many hashes', function() {
+      var b = MerkleBlock(data.JSON[0]);
+      // Add too many hashes
+      var i = 0;
+      while(i <= b.numTransactions) {
+        b.hashes.push('bad' + i++);
+      }
+      (function() {
+        b.filterdTxsHash();
+      }).should.throw('This MerkleBlock contain an invalid Merkle Tree');
+    });
+
+    it('should fail with merkleblocks with too few bit flags', function() {
+      var b = MerkleBlock(JSON.parse(blockJSON));
+      b.flags.pop();
+      (function() {
+        b.filterdTxsHash();
+      }).should.throw('This MerkleBlock contain an invalid Merkle Tree');
+    });
+
+  });
+
   describe('#hasTransaction', function() {
 
     it('should find transactions via hash string', function() {

test/data/merkleblocks.js

@@ -453,6 +453,34 @@ module.exports = {
         nonce : 322045839,
         bits : 419587686,
       }
+    },
+    { // Mainnet FilteredBlock 399775 with filter: 6f64fd5aa9dd01f74c03656d376625cf80328d83d9afebe60cc68b8f0e245bd9
+      "header": {
+      "hash": "0000000000000000011b04bc9f4f3856e299b53a335eb1c42be906237c860bb8",
+      "version": 4,
+      "prevHash": "0000000000000000015373947aa93c7cb16a308fb0a59644d4123072ad24ce5b",
+      "merkleRoot": "ac1841eb3b7d380ee114270e3b1c7df349f1e27e2f0f7891138199bc07e006f8",
+      "time": 1456274787,
+      "bits": 403093919,
+      "nonce": 736568686
+      },
+      "numTransactions": 3309,
+      "hashes": [
+        "adaf1e41a5349a7e2b27e6f2b5fc1186d576d21b47531a410a654439f49bd5a9",
+        "0f64562b6d361757bfdc5926d28cafb7c45e4822b4ad5a14e65530d0c9d44cd2",
+        "c34dec8d5954d8c151c3a594a5a6d1f3a1ec8a1a6c470b27aea879b7757328fb",
+        "c044e5d998fe29cdbe88f87c97c3547f142f5b491cb909d9b0a8e9d3ab7fc984",
+        "51ecd2d2b02b0ca1a3b439eae3adf87ab37dd87f7be0c5b3437cd22350079101",
+        "684ebe37c6eaae2879249ff20b3769d5f2f7ad853a5363a4baee68c0c85777a5",
+        "e561fbeb0faff42f95f2dc8d57d432d4d1a9f84483597a0602e1edc3390f1e33",
+        "02c070afc743c885a6c8d94d15d6e9c3b991c636b4284258dd37686c8792fe44",
+        "6f64fd5aa9dd01f74c03656d376625cf80328d83d9afebe60cc68b8f0e245bd9",
+        "a296fef97b3da0825bac00c794ea234913421b7c1cbb8571978d8d5ba3b16de2",
+        "691c6855c5da434a06cb39a7e47d9337da0e39112ad975cc70cecc882233920a",
+        "6a9e7f8e6d1d8c326a774ff691bdf424252cee710f8e5d9da2c094e999c15efc",
+        "0723ffc695fef989e86784fa2b47097d55f6aac244631536d8d901f5cd9bf170"
+        ],
+      "flags": [171,86,23,0]
     }
   ]
 };