From 331daf0f6a9afb15dcec61c151b2f48b2849be12 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Sun, 23 Oct 2016 04:54:45 -0700
Subject: [PATCH] lru: better atomicity for chain and walletdb.

---
 lib/chain/chaindb.js   | 44 ++++++++++++++++++++++++++++++------------
 lib/wallet/txdb.js     |  9 +++++++--
 lib/wallet/walletdb.js | 18 ++++++++++++-----
 3 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/lib/chain/chaindb.js b/lib/chain/chaindb.js
index ec929024..c3d45e1f 100644
--- a/lib/chain/chaindb.js
+++ b/lib/chain/chaindb.js
@@ -274,8 +274,14 @@ ChainDB.prototype._close = function close() {
 ChainDB.prototype.start = function start() {
   assert(!this.current);
   assert(!this.pending);
+
   this.current = this.db.batch();
   this.pending = this.state.clone();
+
+  this.coinCache.start();
+  this.cacheHash.start();
+  this.cacheHeight.start();
+
   return this.current;
 };
 
@@ -316,11 +322,19 @@ ChainDB.prototype.batch = function batch() {
  */
 
 ChainDB.prototype.drop = function drop() {
+  var batch = this.current;
+
   assert(this.current);
   assert(this.pending);
-  this.current.clear();
+
   this.current = null;
   this.pending = null;
+
+  this.coinCache.drop();
+  this.cacheHash.drop();
+  this.cacheHeight.drop();
+
+  batch.clear();
 };
 
 /**
@@ -337,11 +351,12 @@ ChainDB.prototype.commit = co(function* commit() {
   } catch (e) {
     this.current = null;
     this.pending = null;
+    this.coinCache.drop();
+    this.cacheHash.drop();
+    this.cacheHeight.drop();
     throw e;
   }
 
-  this.current = null;
-
   // Overwrite the entire state
   // with our new best state
   // only if it is committed.
@@ -350,7 +365,12 @@ ChainDB.prototype.commit = co(function* commit() {
   if (this.pending.committed)
     this.state = this.pending;
 
+  this.current = null;
   this.pending = null;
+
+  this.coinCache.commit();
+  this.cacheHash.commit();
+  this.cacheHeight.commit();
 });
 
 /**
@@ -1167,14 +1187,14 @@ ChainDB.prototype._save = co(function* save(entry, block, view) {
   this.put(layout.h(hash), U32(entry.height));
   this.put(layout.e(hash), entry.toRaw());
 
-  this.cacheHash.set(entry.hash, entry);
+  this.cacheHash.push(entry.hash, entry);
 
   if (!view) {
     yield this.saveBlock(block);
     return;
   }
 
-  this.cacheHeight.set(entry.height, entry);
+  this.cacheHeight.push(entry.height, entry);
 
   this.put(layout.n(entry.prevBlock), hash);
   this.put(layout.H(entry.height), hash);
@@ -1218,8 +1238,8 @@ ChainDB.prototype._reconnect = co(function* reconnect(entry, block, view) {
   this.put(layout.n(entry.prevBlock), hash);
   this.put(layout.H(entry.height), hash);
 
-  this.cacheHash.set(entry.hash, entry);
-  this.cacheHeight.set(entry.height, entry);
+  this.cacheHash.push(entry.hash, entry);
+  this.cacheHeight.push(entry.height, entry);
 
   yield this.connectBlock(block, view);
 
@@ -1262,7 +1282,7 @@ ChainDB.prototype._disconnect = co(function* disconnect(entry) {
   this.del(layout.n(entry.prevBlock));
   this.del(layout.H(entry.height));
 
-  this.cacheHeight.remove(entry.height);
+  this.cacheHeight.unpush(entry.height);
 
   block = yield this.getBlock(entry.hash);
 
@@ -1457,10 +1477,10 @@ ChainDB.prototype.connectBlock = co(function* connectBlock(block, view) {
     raw = coins.toRaw();
     if (!raw) {
       this.del(layout.c(coins.hash));
-      this.coinCache.remove(coins.hash);
+      this.coinCache.unpush(coins.hash);
     } else {
       this.put(layout.c(coins.hash), raw);
-      this.coinCache.set(coins.hash, raw);
+      this.coinCache.push(coins.hash, raw);
     }
   }
 
@@ -1553,10 +1573,10 @@ ChainDB.prototype.disconnectBlock = co(function* disconnectBlock(block) {
     raw = coins.toRaw();
     if (!raw) {
       this.del(layout.c(coins.hash));
-      this.coinCache.remove(coins.hash);
+      this.coinCache.unpush(coins.hash);
     } else {
       this.put(layout.c(coins.hash), raw);
-      this.coinCache.set(coins.hash, raw);
+      this.coinCache.push(coins.hash, raw);
     }
   }
 
diff --git a/lib/wallet/txdb.js b/lib/wallet/txdb.js
index 6e8bf329..5a378510 100644
--- a/lib/wallet/txdb.js
+++ b/lib/wallet/txdb.js
@@ -262,6 +262,7 @@ TXDB.prototype.open = co(function* open() {
 
 TXDB.prototype.start = function start() {
   this.pending = this.state.clone();
+  this.coinCache.start();
   return this.wallet.start();
 };
 
@@ -273,6 +274,7 @@ TXDB.prototype.start = function start() {
 TXDB.prototype.drop = function drop() {
   this.pending = null;
   this.events.length = 0;
+  this.coinCache.drop();
   return this.wallet.drop();
 };
 
@@ -284,6 +286,7 @@ TXDB.prototype.drop = function drop() {
 TXDB.prototype.clear = function clear() {
   this.pending = this.state.clone();
   this.events.length = 0;
+  this.coinCache.clear();
   return this.wallet.clear();
 };
 
@@ -300,6 +303,7 @@ TXDB.prototype.commit = co(function* commit() {
   } catch (e) {
     this.pending = null;
     this.events.length = 0;
+    this.coinCache.drop();
     throw e;
   }
 
@@ -319,6 +323,7 @@ TXDB.prototype.commit = co(function* commit() {
 
   this.pending = null;
   this.events.length = 0;
+  this.coinCache.commit();
 });
 
 /**
@@ -677,7 +682,7 @@ TXDB.prototype.saveCredit = function saveCredit(credit, path) {
   var raw = credit.toRaw();
   this.put(layout.c(prevout.hash, prevout.index), raw);
   this.put(layout.C(path.account, prevout.hash, prevout.index), DUMMY);
-  this.coinCache.set(key, raw);
+  this.coinCache.push(key, raw);
 };
 
 /**
@@ -691,7 +696,7 @@ TXDB.prototype.removeCredit = function removeCredit(credit, path) {
   var key = prevout.hash + prevout.index;
   this.del(layout.c(prevout.hash, prevout.index));
   this.del(layout.C(path.account, prevout.hash, prevout.index));
-  this.coinCache.remove(key);
+  this.coinCache.unpush(key);
 };
 
 /**
diff --git a/lib/wallet/walletdb.js b/lib/wallet/walletdb.js
index 75447446..ed118676 100644
--- a/lib/wallet/walletdb.js
+++ b/lib/wallet/walletdb.js
@@ -369,6 +369,8 @@ WalletDB.prototype.getHeight = co(function* getHeight() {
 WalletDB.prototype.start = function start(wallet) {
   assert(!wallet.current, 'Batch already started.');
   wallet.current = this.db.batch();
+  wallet.accountCache.start();
+  wallet.pathCache.start();
   return wallet.current;
 };
 
@@ -381,6 +383,8 @@ WalletDB.prototype.start = function start(wallet) {
 WalletDB.prototype.drop = function drop(wallet) {
   var batch = this.batch(wallet);
   wallet.current = null;
+  wallet.accountCache.drop();
+  wallet.pathCache.drop();
   batch.clear();
 };
 
@@ -392,6 +396,8 @@ WalletDB.prototype.drop = function drop(wallet) {
 
 WalletDB.prototype.clear = function clear(wallet) {
   var batch = this.batch(wallet);
+  wallet.accountCache.clear();
+  wallet.pathCache.clear();
   batch.clear();
 };
 
@@ -414,11 +420,13 @@ WalletDB.prototype.batch = function batch(wallet) {
  * @returns {Promise}
  */
 
-WalletDB.prototype.commit = function commit(wallet) {
+WalletDB.prototype.commit = co(function* commit(wallet) {
   var batch = wallet.current;
   wallet.current = null;
-  return batch.write();
-};
+  yield batch.write();
+  wallet.accountCache.commit();
+  wallet.pathCache.commit();
+});
 
 /**
  * Load the bloom filter into memory.
@@ -862,7 +870,7 @@ WalletDB.prototype.saveAccount = function saveAccount(account) {
   batch.put(layout.a(wid, index), account.toRaw());
   batch.put(layout.i(wid, name), U32(index));
 
-  wallet.accountCache.set(index, account);
+  wallet.accountCache.push(index, account);
 };
 
 /**
@@ -947,7 +955,7 @@ WalletDB.prototype.savePath = co(function* savePath(wallet, path) {
     return;
 
   this.pathMapCache.set(hash, wids);
-  wallet.pathCache.set(hash, path);
+  wallet.pathCache.push(hash, path);
 
   batch.put(layout.p(hash), serializeWallets(wids));
   batch.put(layout.P(wid, hash), path.toRaw());