From 3e8ca41a0a6bcf19c67d46de8126f8ed6d75b7bd Mon Sep 17 00:00:00 2001
From: Manuel Araoz <manuelaraoz@gmail.com>
Date: Thu, 17 Apr 2014 18:06:55 -0300
Subject: [PATCH] optimize public key generation for BIP32 with cache

---
 js/models/core/PublicKeyRing.js | 47 ++++++++++++++--------------
 test/test.performance.js        | 54 +++++++++++++++++++++++++--------
 2 files changed, 64 insertions(+), 37 deletions(-)

diff --git a/js/models/core/PublicKeyRing.js b/js/models/core/PublicKeyRing.js
index 25a31e6b9..9a52cb9cf 100644
--- a/js/models/core/PublicKeyRing.js
+++ b/js/models/core/PublicKeyRing.js
@@ -25,10 +25,12 @@ function PublicKeyRing(opts) {
   this.requiredCopayers = opts.requiredCopayers || 3;
   this.totalCopayers = opts.totalCopayers || 5;
 
-  this.copayersBIP32 = [];
+  this.copayersBIP32 = opts.copayersBIP32 || [];
 
-  this.changeAddressIndex=0;
-  this.addressIndex=0;
+  this.changeAddressIndex= opts.changeAddressIndex || 0;
+  this.addressIndex= opts.addressIndex || 0;
+
+  this.publicKeysCache = opts.publicKeysCache || {};
 }
 
 /*
@@ -45,24 +47,13 @@ PublicKeyRing.Branch = function (index, isChange) {
 };
 
 PublicKeyRing.fromObj = function (data) {
-  if (!data.ts) {
+  if (data instanceof PublicKeyRing) {
     throw new Error('bad data format: Did you use .toObj()?');
   }
-  var config = { networkName: data.networkName || 'livenet' };
-
-  var w = new PublicKeyRing(config);
-
-  w.walletId           = data.walletId;
-  w.requiredCopayers   = data.requiredCopayers;
-  w.totalCopayers      = data.totalCopayers;
-  w.addressIndex       = data.addressIndex;
-  w.changeAddressIndex = data.changeAddressIndex;
-  w.copayersBIP32      = data.copayersExtPubKeys.map( function (pk) {
+  data.copayersBIP32 = data.copayersExtPubKeys.map(function(pk) {
     return new BIP32(pk);
   });
-
-  w.ts = data.ts;
-  return w;
+  return new PublicKeyRing(data);
 };
 
 PublicKeyRing.prototype.toObj = function() {
@@ -77,7 +68,7 @@ PublicKeyRing.prototype.toObj = function() {
     copayersExtPubKeys: this.copayersBIP32.map( function (b) { 
       return b.extendedPublicKeyString(); 
     }),
-    ts: parseInt(Date.now() / 1000),
+    publicKeysCache: this.publicKeysCache
   };
 };
 
@@ -91,7 +82,6 @@ PublicKeyRing.prototype.registeredCopayers = function () {
 };
 
 
-
 PublicKeyRing.prototype.isComplete = function () {
   return this.registeredCopayers() >= this.totalCopayers;
 };
@@ -130,12 +120,19 @@ PublicKeyRing.prototype.addCopayer = function (newEpk) {
 PublicKeyRing.prototype.getPubKeys = function (index, isChange) {
   this._checkKeys();
 
-  var pubKeys = [];
-  var l = this.copayersBIP32.length;
-  for(var i=0; i<l; i++) {
-    var path = PublicKeyRing.Branch(index, isChange); 
-    var bip32 = this.copayersBIP32[i].derive(path);
-    pubKeys[i] = bip32.eckey.public;
+  var path = PublicKeyRing.Branch(index, isChange); 
+  var pubKeys = this.publicKeysCache[path];
+  if (!pubKeys) {
+    pubKeys = [];
+    var l = this.copayersBIP32.length;
+    for(var i=0; i<l; i++) {
+      var bip32 = this.copayersBIP32[i].derive(path);
+      pubKeys[i] = bip32.eckey.public;
+    }
+    this.publicKeysCache[path] = pubKeys;
+    //console.log('cache fill['+path+']='+pubKeys.length);
+  } else {
+    //console.log('cache hit!');
   }
 
   return pubKeys;
diff --git a/test/test.performance.js b/test/test.performance.js
index 68fb8cf24..e1cd7180c 100644
--- a/test/test.performance.js
+++ b/test/test.performance.js
@@ -2,32 +2,25 @@
 
 var chai = chai || require('chai');
 var should = chai.should();
+var PrivateKey = require('../js/models/core/PrivateKey');
+var PublicKeyRing = require('../js/models/core/PublicKeyRing');
 
 describe('Performance tests', function() {
-  var config = {
-    wallet: {
-      requiredCopayers: 1,
-      totalCopayers: 1,
-      spendUnconfirmed: 1,
-    },
-    networkName: 'testnet',
-  };
-
   describe('PrivateKey', function() {
     it('should optimize BIP32 private key gen time with cache', function() {
       var k1 = new PrivateKey();
       var generateN = 25;
       var generated = [];
       var start1 = new Date().getTime();
-      for (var i=0; i<generateN; i++) {
+      for (var i = 0; i < generateN; i++) {
         var k = JSON.stringify(k1.get(i, false).storeObj());
         generated.push(k);
       }
       var delta1 = new Date().getTime() - start1;
       var backup = k1.toObj();
-      var k2 = new PrivateKey(backup);
+      var k2 = PrivateKey.fromObj(backup);
       var start2 = new Date().getTime();
-      for (var i=0; i<generateN; i++) {
+      for (var i = 0; i < generateN; i++) {
         var k = JSON.stringify(k2.get(i, false).storeObj());
         generated[i].should.equal(k);
       }
@@ -35,5 +28,42 @@ describe('Performance tests', function() {
       delta2.should.be.below(delta1);
     });
   });
+  describe('PublicKeyRing', function() {
+    var maxN = 7;
+    for (var n = 1; n < maxN; n++) {
+      for (var m = 1; m <= n; m++) {
+        var M = m;
+        var N = n;
+        (function(M, N) {
+          it('should optimize BIP32 publickey gen time with cache for ' + M + '-of-' + N, function() {
+            var pkr1 = new PublicKeyRing({
+              totalCopayers: N,
+              requiredCopayers: M
+            });
+            for (var i = 0; i < N; i++) {
+              pkr1.addCopayer(); // add new random ext public key
+            }
+            var generateN = 5;
+            var generated = [];
+            var start1 = new Date().getTime();
+            for (var i = 0; i < generateN; i++) {
+              var pubKeys = JSON.stringify(pkr1.getPubKeys(i, false));
+              generated.push(pubKeys);
+            }
+            var delta1 = new Date().getTime() - start1;
+            var backup = pkr1.toObj();
+            var pkr2 = PublicKeyRing.fromObj(backup);
+            var start2 = new Date().getTime();
+            for (var i = 0; i < generateN; i++) {
+              var pubKeys = JSON.stringify(pkr2.getPubKeys(i, false));
+              generated[i].should.equal(pubKeys);
+            }
+            var delta2 = new Date().getTime() - start2;
+            delta2.should.be.below(delta1);
+          });
+        })(M, N);
+      }
+    }
 
+  });
 });