From 30526aaea438b0237430146a6537d3dea81c82a0 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Sun, 4 Dec 2016 02:59:20 -0800
Subject: [PATCH] chaindb: coin cache.

---
 lib/blockchain/chain.js   |  3 ++
 lib/blockchain/chaindb.js | 69 +++++++++++++++++++++++++--------------
 lib/utils/lru.js          | 10 +++++-
 3 files changed, 56 insertions(+), 26 deletions(-)

diff --git a/lib/blockchain/chain.js b/lib/blockchain/chain.js
index f6627610..54e4885a 100644
--- a/lib/blockchain/chain.js
+++ b/lib/blockchain/chain.js
@@ -1409,6 +1409,9 @@ Chain.prototype.finish = function finish(block, entry) {
     block.getSize(),
     block.txs.length,
     time);
+
+  this.logger.debug('Coin Cache: size=%dmb, total=%d.',
+    util.mb(this.db.coinCache.size), this.db.coinCache.total);
 };
 
 /**
diff --git a/lib/blockchain/chaindb.js b/lib/blockchain/chaindb.js
index 30d076fe..4ef37175 100644
--- a/lib/blockchain/chaindb.js
+++ b/lib/blockchain/chaindb.js
@@ -795,25 +795,29 @@ ChainDB.prototype.getTips = function getTips() {
 
 ChainDB.prototype.getCoin = co(function* getCoin(hash, index) {
   var state = this.state;
-  var coins;
+  var raw, coins;
 
   if (this.options.spv)
     return;
 
-  coins = this.coinCache.get(hash);
+  if (this.coinCache.size !== 0) {
+    coins = yield this.getCoins(hash);
 
-  if (coins)
-    return Coins.parseCoin(coins, hash, index);
+    if (!coins)
+      return;
 
-  coins = yield this.db.get(layout.c(hash));
+    if (state === this.state)
+      this.coinCache.set(hash, coins);
 
-  if (!coins)
+    return coins.getCoin(index);
+  }
+
+  raw = yield this.db.get(layout.c(hash));
+
+  if (!raw)
     return;
 
-  if (state === this.state)
-    this.coinCache.set(hash, coins);
-
-  return Coins.parseCoin(coins, hash, index);
+  return Coins.parseCoin(raw, hash, index);
 });
 
 /**
@@ -823,8 +827,7 @@ ChainDB.prototype.getCoin = co(function* getCoin(hash, index) {
  */
 
 ChainDB.prototype.getCoins = co(function* getCoins(hash) {
-  var state = this.state;
-  var coins;
+  var raw, coins;
 
   if (this.options.spv)
     return;
@@ -832,17 +835,16 @@ ChainDB.prototype.getCoins = co(function* getCoins(hash) {
   coins = this.coinCache.get(hash);
 
   if (coins)
-    return Coins.fromRaw(coins, hash);
+    return coins;
 
-  coins = yield this.db.get(layout.c(hash));
+  raw = yield this.db.get(layout.c(hash));
 
-  if (!coins)
+  if (!raw)
     return;
 
-  if (state === this.state)
-    this.coinCache.set(hash, coins);
+  coins = Coins.fromRaw(raw, hash);
 
-  return Coins.fromRaw(coins, hash);
+  return coins;
 });
 
 /**
@@ -1444,8 +1446,10 @@ ChainDB.prototype.saveUpdates = function saveUpdates() {
   var updates = this.stateCache.updates;
   var i, update;
 
-  if (updates.length > 0)
-    this.logger.info('Saving %d state cache updates.', updates.length);
+  if (updates.length === 0)
+    return;
+
+  this.logger.info('Saving %d state cache updates.', updates.length);
 
   for (i = 0; i < updates.length; i++) {
     update = updates[i];
@@ -1643,7 +1647,7 @@ ChainDB.prototype.removeBlock = co(function* removeBlock(hash) {
  */
 
 ChainDB.prototype.saveView = function saveView(view) {
-  var i, coins, raw;
+  var i, coins;
 
   view = view.toArray();
 
@@ -1653,9 +1657,8 @@ ChainDB.prototype.saveView = function saveView(view) {
       this.del(layout.c(coins.hash));
       this.coinCache.unpush(coins.hash);
     } else {
-      raw = coins.toRaw();
-      this.put(layout.c(coins.hash), raw);
-      this.coinCache.push(coins.hash, raw);
+      this.put(layout.c(coins.hash), coins.toRaw());
+      this.coinCache.push(coins.hash, coins);
     }
   }
 };
@@ -2227,7 +2230,23 @@ CacheUpdate.prototype.toRaw = function toRaw() {
  */
 
 function getSize(value) {
-  return 80 + value.length;
+  var half = 4; // Average half of coins
+  var total = 0;
+
+  total += 128; // coins
+  total += 88; // coins hash
+  total += 32; // coins outputs
+
+  // Average compressed coin size
+  // compressed coin = 112
+  // raw = 80
+  // pubkeyhash buffer = 26
+  total += half * (112 + 80 + 26);
+
+  // Average coin size
+  total += half * 509;
+
+  return total;
 }
 
 function BlockPair(hash, height) {
diff --git a/lib/utils/lru.js b/lib/utils/lru.js
index fda80bb7..e553f987 100644
--- a/lib/utils/lru.js
+++ b/lib/utils/lru.js
@@ -28,6 +28,7 @@ function LRU(maxSize, getSize) {
 
   this.map = {};
   this.size = 0;
+  this.total = 0;
   this.head = null;
   this.tail = null;
   this.pending = null;
@@ -66,6 +67,7 @@ LRU.prototype._compact = function _compact() {
     if (this.size <= this.maxSize)
       break;
     this.size -= this._getSize(item);
+    this.total--;
     delete this.map[item.key];
     next = item.next;
     item.prev = null;
@@ -91,6 +93,7 @@ LRU.prototype.reset = function reset() {
 
   for (item = this.head; item; item = next) {
     delete this.map[item.key];
+    this.total--;
     next = item.next;
     item.prev = null;
     item.next = null;
@@ -133,6 +136,7 @@ LRU.prototype.set = function set(key, value) {
   this._appendList(item);
 
   this.size += this._getSize(item);
+  this.total++;
 
   this._compact();
 };
@@ -186,6 +190,7 @@ LRU.prototype.remove = function remove(key) {
     return false;
 
   this.size -= this._getSize(item);
+  this.total--;
 
   delete this.map[key];
 
@@ -463,7 +468,10 @@ function LRUOp(remove, key, value) {
  * @param {Number} size
  */
 
-function NullCache(size) {}
+function NullCache(size) {
+  this.size = 0;
+  this.total = 0;
+}
 
 NullCache.prototype.set = function set(key, value) {};
 NullCache.prototype.remove = function remove(key) {};