From c27466a7c5a45ff42bd81ce5f2d9254c68181f3a Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Wed, 6 Jul 2016 16:35:23 -0700
Subject: [PATCH] avoid duplicate hash table lookups.

---
 lib/bcoin/chaindb.js    | 23 +++++++++++++++++------
 lib/bcoin/chainentry.js |  7 +++++--
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/lib/bcoin/chaindb.js b/lib/bcoin/chaindb.js
index 23d5a807..7f4fa6b3 100644
--- a/lib/bcoin/chaindb.js
+++ b/lib/bcoin/chaindb.js
@@ -317,6 +317,8 @@ ChainDB.prototype.getCache = function getCache(hash) {
  */
 
 ChainDB.prototype.getHeight = function getHeight(hash, callback) {
+  var entry;
+
   if (hash == null || hash < 0) {
     callback = utils.asyncify(callback);
     return callback(null, -1);
@@ -332,9 +334,11 @@ ChainDB.prototype.getHeight = function getHeight(hash, callback) {
     return callback(null, -1);
   }
 
-  if (this.cacheHash.has(hash)) {
+  entry = this.cacheHash.get(hash);
+
+  if (entry) {
     callback = utils.asyncify(callback);
-    return callback(null, this.cacheHash.get(hash).height);
+    return callback(null, entry.height);
   }
 
   this.db.fetch(layout.h(hash), function(data) {
@@ -359,6 +363,8 @@ ChainDB.prototype.getHeight = function getHeight(hash, callback) {
  */
 
 ChainDB.prototype.getHash = function getHash(height, callback) {
+  var entry;
+
   if (height == null || height < 0) {
     callback = utils.asyncify(callback);
     return callback(null, null);
@@ -369,9 +375,11 @@ ChainDB.prototype.getHash = function getHash(height, callback) {
     return callback(null, height);
   }
 
-  if (this.cacheHeight.has(height)) {
+  entry = this.cacheHeight.get(height);
+
+  if (entry) {
     callback = utils.asyncify(callback);
-    return callback(null, this.cacheHeight.get(height).hash);
+    return callback(null, entry.hash);
   }
 
   this.db.fetch(layout.H(height), function(data) {
@@ -445,6 +453,7 @@ ChainDB.prototype.getBoth = function getBoth(block, callback) {
 
 ChainDB.prototype.getEntry = function getEntry(hash, callback) {
   var self = this;
+  var entry;
 
   if (hash == null || hash < 0)
     return utils.nextTick(callback);
@@ -456,8 +465,10 @@ ChainDB.prototype.getEntry = function getEntry(hash, callback) {
     if (!hash)
       return callback();
 
-    if (self.cacheHash.has(hash))
-      return callback(null, self.cacheHash.get(hash));
+    entry = self.cacheHash.get(hash);
+
+    if (entry)
+      return callback(null, entry);
 
     return self.db.fetch(layout.e(hash), function(data) {
       return bcoin.chainentry.fromRaw(self.chain, data);
diff --git a/lib/bcoin/chainentry.js b/lib/bcoin/chainentry.js
index f8204609..ac0543d2 100644
--- a/lib/bcoin/chainentry.js
+++ b/lib/bcoin/chainentry.js
@@ -179,6 +179,7 @@ ChainEntry.prototype.getRetargetAncestors = function getRetargetAncestors(callba
 ChainEntry.prototype.getAncestors = function getAncestors(max, callback) {
   var entry = this;
   var ancestors = [];
+  var cached;
 
   if (max === 0)
     return callback(null, []);
@@ -193,12 +194,14 @@ ChainEntry.prototype.getAncestors = function getAncestors(max, callback) {
     if (ancestors.length >= max)
       return callback(null, ancestors);
 
-    if (!this.chain.db.hasCache(entry.prevBlock)) {
+    cached = this.chain.db.getCache(entry.prevBlock);
+
+    if (!cached) {
       ancestors.pop();
       break;
     }
 
-    entry = this.chain.db.getCache(entry.prevBlock);
+    entry = cached;
   }
 
   (function next(err, entry) {