From 3854f0462428b5e02a7333a46938e810c24847cc Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Thu, 10 Nov 2016 18:49:13 -0800
Subject: [PATCH] chain: spv reorganization.

---
 lib/chain/chain.js   | 36 ++++++++++++++++++++++++++++++++++++
 lib/chain/chaindb.js |  1 +
 2 files changed, 37 insertions(+)

diff --git a/lib/chain/chain.js b/lib/chain/chain.js
index 2bada043..2bddba67 100644
--- a/lib/chain/chain.js
+++ b/lib/chain/chain.js
@@ -795,6 +795,36 @@ Chain.prototype.reorganize = co(function* reorganize(competitor, block) {
   this.emit('reorganize', block, tip.height, tip.hash);
 });
 
+/**
+ * Reorganize the blockchain for SPV.
+ * @private
+ * @param {ChainEntry} competitor - The competing chain's tip.
+ * @param {Block|MerkleBlock} block - The being being added.
+ * @returns {Promise}
+ */
+
+Chain.prototype.reorganizeSPV = co(function* reorganizeSPV(competitor, block) {
+  var tip = this.tip;
+  var fork = yield this.findFork(tip, competitor);
+  var entry;
+
+  assert(fork);
+
+  // Blocks to disconnect.
+  entry = tip;
+  while (entry.hash !== fork.hash) {
+    this.emit('disconnect', entry, entry.toHeaders());
+    entry = yield entry.getPrevious();
+    assert(entry);
+  }
+
+  // Reset the main chain back
+  // to the fork block.
+  yield this._reset(fork.hash);
+
+  this.emit('reorganize', block, tip.height, tip.hash);
+});
+
 /**
  * Disconnect an entry from the chain (updates the tip).
  * @param {ChainEntry} entry
@@ -883,6 +913,12 @@ Chain.prototype.setBestChain = co(function* setBestChain(entry, block, prev) {
   // Time to reorganize the chain.
   if (entry.prevBlock !== this.tip.hash) {
     this.logger.warning('WARNING: Reorganizing chain.');
+
+    // In spv-mode, we reset the
+    // chain and redownload the blocks.
+    if (this.options.spv)
+      return yield this.reorganizeSPV(entry, block);
+
     yield this.reorganize(entry, block);
   }
 
diff --git a/lib/chain/chaindb.js b/lib/chain/chaindb.js
index b69a6fc0..e5c19cd0 100644
--- a/lib/chain/chaindb.js
+++ b/lib/chain/chaindb.js
@@ -1458,6 +1458,7 @@ ChainDB.prototype.removeChain = co(function* removeChain(hash) {
 
     assert(!tip.isGenesis());
 
+    this.del(layout.a(tip.hash));
     this.del(layout.h(tip.hash));
     this.del(layout.e(tip.hash));
     this.del(layout.b(tip.hash));