spv: redownload blocks after reorg. handle reset properly. always save to main chain.

lib/chain/chain.js

@@ -15,6 +15,7 @@ var constants = require('../protocol/constants');
 var utils = require('../utils/utils');
 var Locker = require('../utils/locker');
 var ChainEntry = require('./chainentry');
+var CoinView = require('./coinview');
 var assert = require('assert');
 var VerifyError = require('../utils/errors').VerifyError;
 var VerifyResult = utils.VerifyResult;
@@ -610,10 +611,10 @@ Chain.prototype.verifyInputs = co(function* verifyInputs(block, prev, state) {
   var i, view, tx, valid;
 
   if (this.options.spv)
-    return;
+    return new CoinView();
 
   if (this.isGenesis(block))
-    return;
+    return new CoinView();
 
   view = yield this.db.getCoinView(block);
 
@@ -794,6 +795,42 @@ 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, prev;
+
+  assert(fork);
+
+  // Blocks to disconnect.
+  entry = tip;
+  while (entry.hash !== fork.hash) {
+    this.emit('disconnect', entry, entry.toHeaders());
+    entry = yield entry.getPrevious();
+    assert(entry);
+  }
+
+  // We need to remove the alternate
+  // chain to prevent further reorgs.
+  prev = yield competitor.getPrevious();
+  assert(prev);
+  yield this.db.removeChain(prev, fork);
+
+  // 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
@@ -829,7 +866,12 @@ Chain.prototype.reconnect = co(function* reconnect(entry) {
   var block = yield this.db.getBlock(entry.hash);
   var prev, view;
 
-  assert(block);
+  if (this.options.spv) {
+    assert(!block);
+    block = entry.toHeaders();
+  } else {
+    assert(block);
+  }
 
   prev = yield entry.getPrevious();
   assert(prev);
@@ -871,14 +913,18 @@ Chain.prototype.reconnect = co(function* reconnect(entry) {
  */
 
 Chain.prototype.setBestChain = co(function* setBestChain(entry, block, prev) {
-  var view;
-
-  assert(this.tip);
+  var view, fork;
 
   // A higher fork has arrived.
   // 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);
   }
 
@@ -967,16 +1013,50 @@ Chain.prototype.reset = co(function* reset(height) {
  */
 
 Chain.prototype._reset = co(function* reset(height) {
-  yield this.db.reset(height);
+  var tip = yield this.db.reset(height);
+
+  this.synced = false;
+
+  this.tip = tip;
+  this.height = tip.height;
 
   this.state = yield this.getDeploymentState();
 
+  this.emit('tip', tip);
+
+  if (this.isFull()) {
+    this.synced = true;
+    this.emit('full');
+  }
+
   // Reset the orphan map completely. There may
   // have been some orphans on a forked chain we
   // no longer need.
   this.purgeOrphans();
 });
 
+/**
+ * Reset the chain to a height or hash. Useful for replaying
+ * the blockchain download for SPV.
+ * @param {Hash|Number} block - hash/height
+ * @returns {Promise}
+ */
+
+Chain.prototype.replay = co(function* replay(block) {
+  var entry = yield this.db.get(block);
+
+  if (!entry)
+    throw new Error('Block not found.');
+
+  if (!(yield entry.isMainChain()))
+    throw new Error('Cannot reset on alternate chain.');
+
+  if (entry.hash === this.network.genesis.hash)
+    return yield this.reset(entry.hash);
+
+  yield this.reset(entry.prevBlock);
+});
+
 /**
  * Reset the chain to the desired timestamp (within 2
  * hours). This is useful for replaying the blockchain

lib/chain/chaindb.js

@@ -1351,7 +1351,8 @@ ChainDB.prototype.reset = co(function* reset(block) {
 
     if (tip.hash === entry.hash) {
       this.put(layout.R, this.pending.commit(tip.hash));
-      return yield this.commit();
+      yield this.commit();
+      break;
     }
 
     this.del(layout.H(tip.height));
@@ -1376,28 +1377,39 @@ ChainDB.prototype.reset = co(function* reset(block) {
     tip = yield this.get(tip.prevBlock);
     assert(tip);
   }
+
+  return tip;
 });
 
 /**
- * Reset the chain to a height or hash. Useful for replaying
- * the blockchain download for SPV.
- * @param {Hash|Number} block - hash/height
+ * Remove an alternate chain.
+ * @param {ChainEntry} tip
+ * @param {ChainEntry} entry
  * @returns {Promise}
  */
 
-ChainDB.prototype.replay = co(function* replay(block) {
-  var entry = yield this.get(block);
+ChainDB.prototype.removeChain = co(function* removeChain(tip, entry) {
+  this.logger.debug('Removing alternate chain: %s->%s', tip.rhash, entry.rhash);
 
-  if (!entry)
-    throw new Error('Block not found.');
+  while (!tip.isGenesis()) {
+    if (tip.hash === entry.hash)
+      break;
 
-  if (!(yield entry.isMainChain()))
-    throw new Error('Cannot reset on alternate chain.');
+    this.start();
 
-  if (entry.hash === this.network.genesis.hash)
-    return yield this.reset(entry.hash);
+    this.del(layout.h(tip.hash));
+    this.del(layout.e(tip.hash));
+    this.del(layout.b(tip.hash));
 
-  yield this.reset(entry.prevBlock);
+    yield this.commit();
+
+    this.cacheHash.remove(tip.hash);
+
+    tip = yield this.get(tip.prevBlock);
+    assert(tip);
+  }
+
+  return tip;
 });
 
 /**

lib/node/spvnode.js

@@ -147,7 +147,7 @@ SPVNode.prototype._init = function _init() {
   });
 
   this.chain.on('connect', function(entry, block) {
-    self.walletdb.addBlock(entry, block.txs).catch(onError);
+    self.walletdb.addBlock(entry, block.txs || []).catch(onError);
   });
 
   this.chain.on('disconnect', function(entry, block) {
@@ -220,7 +220,7 @@ SPVNode.prototype.watchData = function watchData(chunks) {
  */
 
 SPVNode.prototype.scan = function rescan(start) {
-  return this.chain.db.replay(start);
+  return this.chain.replay(start);
 };
 
 /**