From 0765f44b5ba221032a6a3cb15271a4d9a389a2e6 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Thu, 18 Aug 2016 01:56:33 -0700
Subject: [PATCH] chaindb: ready for migration.

---
 lib/bcoin/chaindb.js   |  15 ++----
 migrate/chaindb0to1.js | 112 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+), 10 deletions(-)
 create mode 100644 migrate/chaindb0to1.js

diff --git a/lib/bcoin/chaindb.js b/lib/bcoin/chaindb.js
index 4dc74f74..4e9906e2 100644
--- a/lib/bcoin/chaindb.js
+++ b/lib/bcoin/chaindb.js
@@ -299,7 +299,7 @@ ChainDB.prototype._open = function open(callback) {
       utils.btc(self.state.value)
     );
 
-    self.db.checkVersion('V', 0, callback);
+    self.db.checkVersion('V', 1, callback);
   }
 
   this.db.open(function(err) {
@@ -1834,12 +1834,9 @@ ChainState.fromRaw = function fromRaw(data) {
   var state = new ChainState();
   var p = new BufferReader(data);
   state.tip = p.readHash();
-  // XXX Allow just a hash until I write a migration.
-  if (p.left() > 0) {
-    state.tx = p.readU53();
-    state.coin = p.readU53();
-    state.value = p.readU53();
-  }
+  state.tx = p.readU53();
+  state.coin = p.readU53();
+  state.value = p.readU53();
   return state;
 };
 
@@ -1863,9 +1860,7 @@ function pair(prefix, hash) {
 function ipair(prefix, num) {
   var key = new Buffer(5);
   key[0] = prefix;
-  // TODO: Change this to big
-  // endian for saner sorting.
-  key.writeUInt32LE(num, 1, true);
+  key.writeUInt32BE(num, 1, true);
   return key;
 }
 
diff --git a/migrate/chaindb0to1.js b/migrate/chaindb0to1.js
new file mode 100644
index 00000000..1ca09495
--- /dev/null
+++ b/migrate/chaindb0to1.js
@@ -0,0 +1,112 @@
+var bcoin = require('bcoin');
+var assert = require('assert');
+var file = process.argv[2];
+
+assert(typeof file === 'string', 'Please pass in a database path.');
+
+var db = bcoin.ldb({
+  location: file,
+  db: 'leveldb',
+  compression: true,
+  cacheSize: 16 << 20,
+  writeBufferSize: 8 << 20,
+  createIfMissing: false,
+  bufferKeys: true
+});
+
+function makeKey(data) {
+  var height = data.readUInt32LE(1, true);
+  var key = new Buffer(5);
+  key[0] = 0x48;
+  key.writeUInt32BE(height, 1, true);
+  return key;
+}
+
+function updateState(callback) {
+  var hash, batch, ver, p;
+
+  console.log('Updating chain state.');
+
+  db.get('R', function(err, data) {
+    if (err)
+      return callback(err);
+
+    if (!data || data.length < 32)
+      return callback(new Error('No chain state.'));
+
+    hash = data.slice(0, 32);
+
+    p = new bcoin.writer();
+    p.writeHash(hash);
+    p.writeU64(0);
+    p.writeU64(0);
+    p.writeU64(0);
+    p = p.render();
+
+    batch = db.batch();
+
+    batch.put('R', p);
+
+    ver = new Buffer(4);
+    ver.writeUInt32LE(1, 0, true);
+    batch.put('V', ver);
+
+    batch.write(function(err) {
+      if (err)
+        return callback(err);
+      console.log('Updated chain state.');
+      callback();
+    });
+  });
+}
+
+function updateEndian(callback) {
+  var lo = new Buffer('4800000000', 'hex');
+  var hi = new Buffer('48ffffffff', 'hex');
+  var batch = db.batch();
+  var total = 0;
+
+  console.log('Updating endianness.');
+  console.log('Iterating...');
+
+  db.iterate({
+    gte: lo,
+    lte: hi,
+    values: true,
+    parse: function(key, value) {
+      batch.del(key);
+      batch.put(makeKey(key), value);
+      total++;
+    }
+  }, function(err) {
+    if (err)
+      throw err;
+
+    console.log('Migrating %d items.', total);
+
+    batch.write(function(err) {
+      if (err)
+        throw err;
+      console.log('Migrated endianness.');
+      callback();
+    });
+  });
+}
+
+db.open(function(err) {
+  if (err)
+    throw err;
+
+  console.log('Opened %s.', file);
+
+  updateState(function(err) {
+    if (err)
+      throw err;
+    updateEndian(function(err) {
+      if (err)
+        throw err;
+      console.log('Migration complete.');
+      process.exit(0);
+    });
+  });
+});