From f09a4dc8f70f8d90ec599e8af162d25652651822 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Thu, 10 Mar 2016 14:39:37 -0800
Subject: [PATCH] blockdb improvements.

---
 lib/bcoin/blockdb.js | 127 ++++++++++++++++++++++---------------------
 1 file changed, 66 insertions(+), 61 deletions(-)

diff --git a/lib/bcoin/blockdb.js b/lib/bcoin/blockdb.js
index 9908d95c..2f659342 100644
--- a/lib/bcoin/blockdb.js
+++ b/lib/bcoin/blockdb.js
@@ -76,9 +76,9 @@ BlockDB.prototype.close = function close(callback) {
 };
 
 BlockDB.prototype.migrate = function migrate(blockSize, compression, callback) {
-  var options, db, pending, stream, total, done;
+  var options, db, iter, total;
 
-  callback = utils.once(callback);
+  callback = utils.ensure(callback);
   options = utils.merge({}, this.db.options);
 
   if (blockSize != null)
@@ -89,43 +89,48 @@ BlockDB.prototype.migrate = function migrate(blockSize, compression, callback) {
 
   options.maxOpenFiles = 60000;
 
-  utils.print('Migrating DB with options:');
-  utils.print(options);
+  utils.debug('Migrating DB with options:');
+  utils.debug(options);
 
-  db = levelup(this.file + '.migrated', options);
+  db = new levelup(this.file + '.migrated', options);
 
-  stream = this.db.createReadStream();
-
-  pending = 0;
   total = 0;
 
-  function onPut(err) {
-    if (err)
-      return callback(err);
-
-    if (++total % 10000 === 0)
-      utils.print('%d written.', total);
-
-    pending--;
-
-    if (done && !pending)
-      callback();
-  }
-
-  stream.on('data', function(data) {
-    pending++;
-    db.put(data.key, data.value, onPut);
+  iter = this.db.db.iterator({
+    keys: true,
+    values: true,
+    fillCache: false,
+    keyAsBuffer: false,
+    valueAsBuffer: true
   });
 
-  stream.on('error', function(err) {
-    callback(err);
-  });
+  (function next() {
+    iter.next(function(err, key, value) {
+      var height;
 
-  stream.on('end', function() {
-    done = true;
-    if (!pending)
-      callback();
-  });
+      if (err) {
+        return iter.end(function() {
+          callback(err);
+        });
+      }
+
+      if (key === undefined)
+        return iter.end(callback);
+
+      db.put(key, value, function(err) {
+        if (err) {
+          return iter.end(function() {
+            callback(err);
+          });
+        }
+
+        if (++total % 10000 === 0)
+          utils.print('%d written.', total);
+
+        next();
+      });
+    });
+  })();
 };
 
 BlockDB.prototype.saveBlock = function saveBlock(block, callback) {
@@ -169,6 +174,8 @@ BlockDB.prototype.connectBlock = function connectBlock(block, callback, batch) {
   var self = this;
 
   this._getCoinBlock(block, function(err, block) {
+    var height;
+
     if (err)
       return callback(err);
 
@@ -182,6 +189,10 @@ BlockDB.prototype.connectBlock = function connectBlock(block, callback, batch) {
 
     batch.put('b/h/' + pad32(block.height), block.hash());
 
+    height = new Buffer(4);
+    utils.writeU32(height, block.height, 0);
+    batch.put('b/t', height);
+
     block.txs.forEach(function(tx, i) {
       var hash = tx.hash('hex');
       var uniq = {};
@@ -262,6 +273,7 @@ BlockDB.prototype.disconnectBlock = function disconnectBlock(hash, callback, bat
     if (typeof hash === 'string')
       assert(block.hash('hex') === hash);
 
+    batch.del('b/t');
     batch.del('b/h/' + pad32(block.height));
 
     block.txs.forEach(function(tx, i) {
@@ -937,43 +949,36 @@ BlockDB.prototype.isSpent = function isSpent(hash, index, callback) {
 
 BlockDB.prototype.getHeight = function getHeight(callback) {
   var self = this;
-  var maxHeight = -1;
-  var iter;
 
-  iter = this.db.db.iterator({
-    gte: 'b/h',
-    lte: 'b/h~',
-    keys: true,
-    values: false,
-    fillCache: false,
-    keyAsBuffer: false
+  return this.db.get('b/t', function(err, height) {
+    if (err && err.type !== 'NotFoundError')
+      return callback(err);
+
+    if (!height)
+      return callback(null, -1);
+
+    return callback(null, utils.readU32(height, 0));
   });
+};
 
-  (function next() {
-    iter.next(function(err, key, value) {
-      var height;
+BlockDB.prototype.getTipHash = function getTipHash(callback) {
+  return this.getHeight(function(err, height) {
+    if (err)
+      return callback(err);
 
-      if (err) {
-        return iter.end(function() {
-          callback(err);
-        });
-      }
+    if (height === -1)
+      return callback();
 
-      if (key === undefined) {
-        return iter.end(function(err) {
-          if (err)
-            return callback(err);
-          callback(null, maxHeight);
-        });
-      }
+    return self.db.get('b/h/' + pad32(height), function(err, hash) {
+      if (err && err.type !== 'NotFoundError')
+        return callback(err);
 
-      height = +key.split('/')[2];
-      if (height > maxHeight)
-        maxHeight = height;
+      if (!hash)
+        return callback();
 
-      next();
+      return callback(null, utils.toHex(hash));
     });
-  })();
+  });
 };
 
 BlockDB.prototype.reset = function reset(height, callback, emit) {