From 6b51badfa9c21de9b85d292ae061049ccaf2ef31 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Sat, 5 Mar 2016 06:19:05 -0800
Subject: [PATCH] better reorgs.

---
 lib/bcoin/blockdb.js | 400 +++++++++++++++++++++++++++++++++++++++----
 lib/bcoin/chain.js   | 265 ++++++++++++----------------
 lib/bcoin/chaindb.js | 156 +++++++++--------
 lib/bcoin/pool.js    |   2 +-
 4 files changed, 560 insertions(+), 263 deletions(-)

diff --git a/lib/bcoin/blockdb.js b/lib/bcoin/blockdb.js
index ffa0ce1c..75282ce1 100644
--- a/lib/bcoin/blockdb.js
+++ b/lib/bcoin/blockdb.js
@@ -397,6 +397,287 @@ BlockDB.prototype.removeBlock = function removeBlock(hash, callback) {
   });
 };
 
+BlockDB.prototype.saveBlock = function saveBlock(block, callback) {
+  var self = this;
+
+  this.data.saveAsync(block._raw, function(err, data) {
+    var batch, blockOffset;
+
+    if (err)
+      return callback(err);
+
+    batch = self.index.batch();
+
+    block._fileOffset = data.offset;
+    assert(block._size === data.size);
+
+    blockOffset = self.createOffset(block._size, block._fileOffset, block.height);
+
+    batch.put('b/b/' + block.hash('hex'), blockOffset);
+
+    self.connectBlock(block, callback, batch, blockOffset);
+  });
+};
+
+BlockDB.prototype.removeBlock = function removeBlock(hash, callback) {
+  var self = this;
+
+  this._getCoinBlock(hash, function(err, block) {
+    var batch;
+
+    if (err)
+      return callback(err);
+
+    if (!block)
+      return callback();
+
+    batch = self.index.batch();
+
+    batch.del('b/b/' + block.hash('hex'));
+
+    function cb(err) {
+      if (err)
+        return callback(err);
+
+      return callback(null, block);
+
+      // XXX This seems to be truncating too much right now
+      self.data.truncateAsync(block._fileOffset, function(err) {
+        if (err)
+          return callback(err);
+        return callback(null, block);
+      });
+    }
+
+    self.disconnectBlock(hash, cb, batch);
+  });
+};
+
+BlockDB.prototype.connectBlock = function connectBlock(block, callback, batch, blockOffset) {
+  var self = this;
+
+  this._getCoinBlock(block, function(err, block) {
+    if (err)
+      return callback(err);
+
+    if (!block) {
+      assert(!batch);
+      return callback();
+    }
+
+    if (!batch)
+      batch = self.index.batch();
+
+    if (!blockOffset)
+      blockOffset = self.createOffset(block._size, block._fileOffset, block.height);
+
+    batch.put('b/h/' + block.height, blockOffset);
+
+    block.txs.forEach(function(tx, i) {
+      var hash = tx.hash('hex');
+      var uniq = {};
+      var txOffset;
+
+      txOffset = self.createOffset(
+        tx._size,
+        block._fileOffset + tx._offset,
+        block.height
+      );
+
+      batch.put('t/t/' + hash, txOffset);
+
+      tx.inputs.forEach(function(input) {
+        var type = input.getType();
+        var address = input.getAddress();
+        var uaddr;
+
+        if (input.isCoinbase())
+          return;
+
+        if (type === 'pubkey' || type === 'multisig')
+          address = null;
+
+        uaddr = address;
+
+        if (uaddr) {
+          if (!uniq[uaddr])
+            uniq[uaddr] = true;
+          else
+            uaddr = null;
+        }
+
+        if (uaddr)
+          batch.put('t/a/' + uaddr + '/' + hash, txOffset);
+
+        if (address) {
+          batch.del(
+            'u/a/' + address
+            + '/' + input.prevout.hash
+            + '/' + input.prevout.index);
+        }
+
+        batch.del('u/t/' + input.prevout.hash + '/' + input.prevout.index);
+
+        if (self.options.cache)
+          self.cache.unspent.remove(input.prevout.hash + '/' + input.prevout.index);
+      });
+
+      tx.outputs.forEach(function(output, i) {
+        var type = output.getType();
+        var address = output.getAddress();
+        var uaddr, coinOffset;
+
+        if (type === 'pubkey' || type === 'multisig')
+          address = null;
+
+        uaddr = address;
+
+        if (uaddr) {
+          if (!uniq[uaddr])
+            uniq[uaddr] = true;
+          else
+            uaddr = null;
+        }
+
+        coinOffset = self.createOffset(
+          output._size,
+          block._fileOffset + tx._offset + output._offset,
+          block.height
+        );
+
+        if (uaddr)
+          batch.put('t/a/' + uaddr + '/' + hash, txOffset);
+
+        if (address)
+          batch.put('u/a/' + address + '/' + hash + '/' + i, coinOffset);
+
+        batch.put('u/t/' + hash + '/' + i, coinOffset);
+      });
+    });
+
+    batch.write(function(err) {
+      if (err)
+        return callback(err);
+      self.emit('save block', block);
+      return callback(null, block);
+    });
+  });
+};
+
+BlockDB.prototype.disconnectBlock = function disconnectBlock(hash, callback, batch) {
+  var self = this;
+
+  this._getCoinBlock(hash, function(err, block) {
+    var batch;
+
+    if (err)
+      return callback(err);
+
+    if (!block) {
+      assert(!batch);
+      return callback();
+    }
+
+    if (!batch)
+      batch = self.index.batch();
+
+    if (typeof hash === 'string')
+      assert(block.hash('hex') === hash);
+
+    batch.del('b/h/' + block.height);
+
+    block.txs.forEach(function(tx, i) {
+      var hash = tx.hash('hex');
+      var uniq = {};
+
+      if (self.options.cache)
+        self.cache.tx.remove(hash);
+
+      batch.del('t/t/' + hash);
+
+      tx.inputs.forEach(function(input) {
+        var type = input.getType();
+        var address = input.getAddress();
+        var uaddr, coinOffset;
+
+        if (input.isCoinbase())
+          return;
+
+        if (type === 'pubkey' || type === 'multisig')
+          address = null;
+
+        uaddr = address;
+
+        if (uaddr) {
+          if (!uniq[uaddr])
+            uniq[uaddr] = true;
+          else
+            uaddr = null;
+        }
+
+        assert(input.output._fileOffset >= 0);
+
+        coinOffset = self.createOffset(
+          input.output._size,
+          input.output._fileOffset,
+          input.output.height
+        );
+
+        if (uaddr)
+          batch.del('t/a/' + uaddr + '/' + hash);
+
+        if (address) {
+          batch.put('u/a/' + address
+            + '/' + input.prevout.hash
+            + '/' + input.prevout.index,
+            coinOffset);
+        }
+
+        batch.put('u/t/'
+          + input.prevout.hash
+          + '/' + input.prevout.index,
+          coinOffset);
+      });
+
+      tx.outputs.forEach(function(output, i) {
+        var type = output.getType();
+        var address = output.getAddress();
+        var uaddr;
+
+        if (type === 'pubkey' || type === 'multisig')
+          address = null;
+
+        uaddr = address;
+
+        if (uaddr) {
+          if (!uniq[uaddr])
+            uniq[uaddr] = true;
+          else
+            uaddr = null;
+        }
+
+        if (uaddr)
+          batch.del('t/a/' + uaddr + '/' + hash);
+
+        if (address)
+          batch.del('u/a/' + address + '/' + hash + '/' + i);
+
+        batch.del('u/t/' + hash + '/' + i);
+
+        if (self.options.cache)
+          self.cache.unspent.remove(hash + '/' + i);
+      });
+    });
+
+    batch.write(function(err) {
+      if (err)
+        return callback(err);
+      self.emit('remove block', block);
+      return callback(null, block);
+    });
+  });
+};
+
 BlockDB.prototype.fillCoins = function fillCoins(txs, callback) {
   var self = this;
   var pending = txs.length;
@@ -788,6 +1069,93 @@ BlockDB.prototype.getTX = function getTX(hash, callback) {
   });
 };
 
+BlockDB.prototype.getFullTX = function getFullTX(hash, callback) {
+  var self = this;
+
+  return this.getTX(hash, function(err, tx) {
+    if (err)
+      return callback(err);
+
+    if (!tx)
+      return callback();
+
+    return self.fillTX(tx, function(err) {
+      if (err)
+        return callback(err);
+
+      return callback(null, tx);
+    });
+  });
+};
+
+BlockDB.prototype.getFullBlock = function getFullBlock(hash, callback) {
+  var self = this;
+
+  return this.getBlock(hash, function(err, block) {
+    if (err)
+      return callback(err);
+
+    if (!block)
+      return callback();
+
+    return self.fillTXs(block.txs, function(err) {
+      if (err)
+        return callback(err);
+
+      return callback(null, block);
+    });
+  });
+};
+
+BlockDB.prototype._getCoinBlock = function _getCoinBlock(hash, callback) {
+  var self = this;
+
+  if (hash instanceof bcoin.block)
+    return callback(null, hash);
+
+  return this.getBlock(hash, function(err, block) {
+    if (err)
+      return callback(err);
+
+    if (!block)
+      return callback();
+
+    return self.fillBlock(block, callback);
+  });
+};
+
+BlockDB.prototype.fillBlock = function fillBlock(block, callback) {
+  var self = this;
+
+  return this.fillCoins(block.txs, function(err) {
+    var coins, i, tx, hash, j, input, id;
+
+    if (err)
+      return callback(err);
+
+    coins = {};
+
+    for (i = 0; i < block.txs.length; i++) {
+      tx = block.txs[i];
+      hash = tx.hash('hex');
+
+      for (j = 0; j < tx.inputs.length; j++) {
+        input = tx.inputs[j];
+        id = input.prevout.hash + '/' + input.prevout.index;
+        if (!input.output && coins[id]) {
+          input.output = coins[id];
+          delete coins[id];
+        }
+      }
+
+      for (j = 0; j < tx.outputs.length; j++)
+        coins[hash + '/' + j] = bcoin.coin(tx, j);
+    }
+
+    return callback(null, block);
+  });
+};
+
 BlockDB.prototype.getBlock = function getBlock(hash, callback) {
   var self = this;
   var id = 'b/b/' + hash;
@@ -995,7 +1363,7 @@ BlockDB.prototype.getHeight = function getHeight(callback) {
   })();
 };
 
-BlockDB.prototype.resetHeight = function resetHeight(height, callback, emit) {
+BlockDB.prototype.reset = function reset(height, callback, emit) {
   var self = this;
   this.getHeight(function(err, currentHeight) {
     if (err)
@@ -1035,36 +1403,6 @@ BlockDB.prototype.getTip = function getTip(callback) {
   return callback(null, tip);
 };
 
-BlockDB.prototype.resetHash = function resetHash(hash, callback, emit) {
-  var self = this;
-  this.getTip(function(err, tip) {
-    if (err)
-      return callback(err);
-
-    if (!tip)
-      return callback(new Error('Cannot reset to hash ' + hash));
-
-    (function next(tip) {
-      if (tip === hash)
-        return callback();
-
-      self.removeBlock(tip, function(err, block) {
-        if (err)
-          return callback(err);
-
-        if (!block)
-          return callback(new Error('Cannot reset all blocks.'));
-
-        // Emit the blocks we removed.
-        if (emit)
-          emit(block);
-
-        next(block.prevBlock);
-      });
-    })(hash);
-  });
-};
-
 BlockDB.prototype._getEntry = function _getEntry(height, callback) {
   if (!this.node)
     return callback();
diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index f327d9cc..1e23e6f6 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -151,7 +151,7 @@ Chain.prototype._init = function _init() {
         if (err)
           throw err;
 
-        self.syncHeight(function(err) {
+        self._syncHeight(function(err) {
           if (err)
             throw err;
 
@@ -303,7 +303,7 @@ Chain.prototype._preload = function _preload(callback) {
 
   stream.on('error', function(err) {
     var start = Math.max(0, height - 2);
-    self.resetHeight(start, function(e) {
+    self.reset(start, function(e) {
       if (e)
         throw e;
       return callback(err, start + 1);
@@ -345,7 +345,7 @@ Chain.prototype._preload = function _preload(callback) {
       if (lastEntry && entry.prevBlock !== lastEntry.hash) {
         start = Math.max(0, height - 2);
         stream.destroy();
-        return self.resetHeight(start, function(err) {
+        return self.reset(start, function(err) {
           if (err)
             throw err;
           return callback(new Error('Corrupt headers.'), start + 1);
@@ -357,7 +357,7 @@ Chain.prototype._preload = function _preload(callback) {
       if (!block.verifyHeaders()) {
         start = Math.max(0, height - 2);
         stream.destroy();
-        return self.resetHeight(start, function(err) {
+        return self.reset(start, function(err) {
           if (err)
             throw err;
           return callback(new Error('Bad headers.'), start + 1);
@@ -651,7 +651,7 @@ Chain.prototype._checkInputs = function _checkInputs(block, prev, flags, callbac
       scriptCheck = false;
   }
 
-  this._fillBlock(block, function(err) {
+  this.blockdb.fillBlock(block, function(err) {
     var i, j, input, hash;
     var sigops = 0;
 
@@ -740,38 +740,6 @@ Chain.prototype._checkReward = function _checkReward(block) {
   return true;
 };
 
-Chain.prototype._fillBlock = function _fillBlock(block, callback) {
-  var self = this;
-
-  return this.blockdb.fillCoins(block.txs, function(err) {
-    var coins, i, tx, hash, j, input, id;
-
-    if (err)
-      return callback(err);
-
-    coins = {};
-
-    for (i = 0; i < block.txs.length; i++) {
-      tx = block.txs[i];
-      hash = tx.hash('hex');
-
-      for (j = 0; j < tx.inputs.length; j++) {
-        input = tx.inputs[j];
-        id = input.prevout.hash + '/' + input.prevout.index;
-        if (!input.output && coins[id]) {
-          input.output = coins[id];
-          delete coins[id];
-        }
-      }
-
-      for (j = 0; j < tx.outputs.length; j++)
-        coins[hash + '/' + j] = bcoin.coin(tx, j);
-    }
-
-    return callback();
-  });
-};
-
 Chain.prototype.getHeight = function getHeight(hash) {
   if (Buffer.isBuffer(hash))
     hash = utils.toHex(hash);
@@ -828,12 +796,6 @@ Chain.prototype._findFork = function _findFork(fork, longer, callback) {
 Chain.prototype._reorganize = function _reorganize(entry, callback) {
   var self = this;
 
-  // Find the fork and connect/disconnect blocks.
-  // NOTE: Bitcoind disconnects and reconnects the
-  // forked block for some reason. We don't do this
-  // since it was already emitted for the wallet
-  // and mempool to handle. Technically bitcoind
-  // shouldn't have done it either.
   return this._findFork(this.tip, entry, function(err, fork) {
     if (err)
       return callback(err);
@@ -842,34 +804,7 @@ Chain.prototype._reorganize = function _reorganize(entry, callback) {
 
     // Disconnect blocks/txs.
     function disconnect(callback) {
-      self.db.resetHash(fork.hash, function(err) {
-        if (err)
-          return callback(err);
-
-        if (!self.blockdb)
-          return callback();
-
-        self.blockdb.resetHash(fork.hash, function(err) {
-          if (err)
-            return callback(err);
-
-          return callback();
-        }, function(block) {
-          self.emit('remove block', block);
-        });
-      }, function(entry) {
-        self.emit('remove entry', entry);
-      });
-    }
-
-    // Connect blocks/txs.
-    function connect(callback) {
-      var entries = [];
-
       (function collect(entry) {
-        if (entry.hash === fork.hash)
-          return finish();
-
         self.db.get(entry.prevBlock, function(err, entry) {
           if (err)
             return callback(err);
@@ -877,6 +812,67 @@ Chain.prototype._reorganize = function _reorganize(entry, callback) {
           assert(entry);
 
           entries.push(entry);
+
+          if (entry.hash === fork.hash)
+            return finish();
+
+          collect(entry);
+        });
+      })(self.tip);
+
+      function finish() {
+        assert(entries.length > 0);
+
+        utils.forEachSerial(entries, function(entry, next) {
+          self.db.disconnect(entry, function(err) {
+            if (err)
+              return next(err);
+
+            self.emit('remove entry', entry);
+
+            next();
+          });
+        }, function(err) {
+          if (err)
+            return callback(err);
+
+          if (!self.blockdb)
+            return callback();
+
+          utils.forEachSerial(entries, function(entry, next) {
+            self.blockdb.disconnectBlock(entry.hash, function(err, block) {
+              if (err)
+                return next(err);
+
+              self.emit('remove block', entry);
+
+              next();
+            });
+          }, function(err) {
+            if (err)
+              return callback(err);
+            return callback();
+          });
+        });
+      }
+    }
+
+    // Connect blocks/txs.
+    function connect(callback) {
+      var entries = [];
+
+      (function collect(entry) {
+        self.db.get(entry.prevBlock, function(err, entry) {
+          if (err)
+            return callback(err);
+
+          assert(entry);
+
+          entries.push(entry);
+
+          if (entry.hash === fork.hash)
+            return finish();
+
           collect(entry);
         });
       })(entry);
@@ -885,29 +881,39 @@ Chain.prototype._reorganize = function _reorganize(entry, callback) {
         entries = entries.slice().reverse();
         assert(entries.length > 0);
 
-        entries.forEach(function(entry) {
-          self.emit('add entry', entry);
-        });
-
-        if (!self.blockdb)
-          return callback();
-
-        utils.forEachSerial(entries, function(err, entry) {
-          return self.blockdb.getBlock(entry.hash, function(err, block) {
+        utils.forEachSerial(entries, function(entry, next) {
+          self.db.connect(entry, function(err) {
             if (err)
-              return callback(err);
+              return next(err);
 
-            assert(block);
+            self.emit('add entry', entry);
 
-            self.emit('add block', block);
-
-            next();
+            return next();
           });
         }, function(err) {
           if (err)
             return callback(err);
 
-          return callback();
+          if (!self.blockdb)
+            return callback();
+
+          utils.forEachSerial(entries, function(err, entry) {
+            self.blockdb.connectBlock(entry.hash, function(err, block) {
+              if (err)
+                return callback(err);
+
+              assert(block);
+
+              self.emit('add block', block);
+
+              next();
+            });
+          }, function(err) {
+            if (err)
+              return callback(err);
+
+            return callback();
+          });
         });
       }
     }
@@ -972,101 +978,52 @@ Chain.prototype._setBestChain = function _setBestChain(entry, block, callback) {
   }
 };
 
-Chain.prototype.resetHeight = function resetHeight(height, callback, force) {
+Chain.prototype.reset = function reset(height, callback, force) {
   var self = this;
+  var chainHeight;
 
-  var unlock = this._lock(resetHeight, [height, callback], force);
+  var unlock = this._lock(reset, [height, callback], force);
   if (!unlock)
     return;
 
+  callback = utils.ensure(callback);
+
   function done(err, result) {
-    unlock();
-    if (callback)
-      callback(err, result);
-  }
-
-  this.db.resetHeight(height, function(err) {
-    if (err)
-      return done(err);
-
     // Reset the orphan map completely. There may
     // have been some orphans on a forked chain we
     // no longer need.
     self.purgeOrphans();
     self.purgePending();
 
-    return done();
-  }, function(entry) {
-    self.emit('remove entry', entry);
-  });
-};
-
-Chain.prototype.revertHeight = function revertHeight(height, callback, force) {
-  var self = this;
-  var chainHeight;
-
-  var unlock = this._lock(revertHeight, [height, callback], force);
-  if (!unlock)
-    return;
-
-  callback = utils.asyncify(callback);
-
-  function done(err, result) {
     unlock();
     callback(err, result);
   }
 
-  this.db.getChainHeight(function(err, chainHeight) {
+  this.db.reset(height, function(err) {
     if (err)
       return done(err);
 
-    if (chainHeight == null || chainHeight < 0)
-      return done(new Error('Bad chain height.'));
-
-    if (chainHeight < height)
-      return done(new Error('Cannot reset height.'));
-
-    if (chainHeight === height)
+    if (!self.blockdb)
       return done();
 
-    this.resetHeight(height, function(err) {
+    self.blockdb.reset(height, function(err) {
       if (err)
         return done(err);
 
-      if (!self.blockdb)
-        return done();
-
-      self.blockdb.getHeight(function(err, blockHeight) {
-        if (err)
-          return done(err);
-
-        if (blockHeight < 0)
-          return done(new Error('Bad block height.'));
-
-        if (blockHeight < height)
-          return done(new Error('Cannot reset height.'));
-
-        if (blockHeight === height)
-          return done();
-
-        self.blockdb.resetHeight(height, function(err) {
-          if (err)
-            return done(err);
-
-          return done();
-        }, function(block) {
-          self.emit('remove block', block);
-        });
-      });
-    }, true);
+      return done();
+    }, function(block) {
+      self.emit('remove block', block);
+    });
+  }, function(entry) {
+    self.emit('remove entry', block);
   });
 };
 
-Chain.prototype.syncHeight = function syncHeight(callback, force) {
+Chain.prototype._syncHeight = function _syncHeight(callback, force) {
   var self = this;
   var chainHeight;
 
-  var unlock = this._lock(syncHeight, [callback], force);
+  var unlock = this._lock(_syncHeight, [callback], force);
   if (!unlock)
     return;
 
@@ -1101,18 +1058,16 @@ Chain.prototype.syncHeight = function syncHeight(callback, force) {
 
       if (blockHeight < chainHeight) {
         utils.debug('ChainDB is higher than BlockDB. Syncing...');
-        return self.resetHeight(blockHeight, done, true);
+        return self.db.reset(blockHeight, done);
       }
 
       if (blockHeight > chainHeight) {
         utils.debug('BlockDB is higher than ChainDB. Syncing...');
-        self.blockdb.resetHeight(chainHeight, function(err) {
+        self.blockdb.reset(chainHeight, function(err) {
           if (err)
             return done(err);
 
           return done();
-        }, function(block) {
-          self.emit('remove block', block);
         });
       }
     });
@@ -1141,7 +1096,7 @@ Chain.prototype.resetTime = function resetTime(ts, callback, force) {
       return;
     }
 
-    self.resetHeight(entry.height, function(err) {
+    self.reset(entry.height, function(err) {
       unlock();
       if (callback)
         callback(err);
diff --git a/lib/bcoin/chaindb.js b/lib/bcoin/chaindb.js
index db1e5b0b..8919218d 100644
--- a/lib/bcoin/chaindb.js
+++ b/lib/bcoin/chaindb.js
@@ -360,87 +360,66 @@ ChainDB.prototype.getTip = function getTip(callback) {
   });
 };
 
-ChainDB.prototype.remove = function remove(block, callback, emit) {
+ChainDB.prototype.connect = function connect(block, callback, emit) {
   var self = this;
-  var blocks = [];
-  var entry, hash, height;
+  var batch;
 
-  this.get(block, function(err, data) {
+  this._get(block, function(err, entry) {
     if (err)
       return callback(err);
 
-    if (!data)
+    if (!entry)
       return callback();
 
-    hash = data.hash;
-    height = data.height;
+    batch = self.db.batch();
 
-    (function next(err, nextHash) {
-      if (err && err.type !== 'NotFoundError')
-        return callback(err);
+    batch.put('c/b/' + entry.height, new Buffer(entry.hash, 'hex'));
+    batch.put('c/t', new Buffer(entry.hash, 'hex'));
 
-      if (!nextHash)
-        return done();
+    self.cacheHeight.set(entry.height, entry);
 
-      entry = {
-        hash: utils.toHex(nextHash),
-        height: height++
-      };
-
-      self.cacheHash.remove(entry.hash);
-      self.cacheHeight.remove(entry.height);
-
-      if (emit)
-        emit(entry);
-
-      blocks.push(entry);
-
-      self.db.get('c/n/' + entry.hash, next);
-    })(null, hash);
-  });
-
-  function done() {
-    var batch = self.db.batch();
-    utils.forEach(blocks, function(entry, next, i) {
-      batch.del('c/b/' + entry.height);
-      batch.del('c/h/' + entry.hash);
-      batch.del('c/c/' + entry.hash);
-
-      if (i === 0) {
-        return self.get(entry.hash, function(err, entry) {
-          if (err)
-            return callback(err);
-
-          assert(entry);
-
-          return self.get(entry.prevBlock, function(err, entry) {
-            if (err)
-              return callback(err);
-
-            assert(entry);
-
-            batch.put('c/t', new Buffer(entry.hash, 'hex'));
-            batch.del('c/n/' + entry.hash);
-
-            next();
-          });
-        });
-      }
-
-      batch.del('c/n/' + blocks[i - 1].hash);
-
-      return utils.nextTick(next);
-    }, function(err) {
+    batch.write(function(err) {
       if (err)
         return callback(err);
-
-      batch.write(callback);
+      return callback(null, entry);
     });
-  }
+  });
+};
+
+ChainDB.prototype.disconnect = function disconnect(block, callback) {
+  var self = this;
+  var batch;
+
+  this._get(block, function(err, entry) {
+    if (err)
+      return callback(err);
+
+    if (!entry)
+      return callback();
+
+    batch = self.db.batch();
+
+    batch.del('c/b/' + entry.height);
+    batch.put('c/t', new Buffer(entry.prevBlock, 'hex'));
+
+    self.cacheHeight.remove(entry.height);
+
+    batch.write(function(err) {
+      if (err)
+        return callback(err);
+      return callback(null, entry);
+    });
+  });
+};
+
+ChainDB.prototype._get = function _get(block, callback) {
+  if (block instanceof bcoin.chainblock)
+    return callback(null, block);
+  return this.get(block, callback);
 };
 
 ChainDB.prototype.getNextHash = function getNextHash(hash, callback) {
-  return this.get('c/n/' + hash, function(err, nextHash) {
+  return this.db.get('c/n/' + hash, function(err, nextHash) {
     if (err && err.type !== 'NotFoundError')
       return callback(err);
 
@@ -451,24 +430,49 @@ ChainDB.prototype.getNextHash = function getNextHash(hash, callback) {
   });
 };
 
-ChainDB.prototype.resetHeight = function resetHeight(height, callback, emit) {
+ChainDB.prototype.reset = function reset(block, callback, emit) {
   var self = this;
+  var batch;
 
-  callback = utils.asyncify(callback);
-
-  return this.removeEntry(height + 1, callback, emit);
-};
-
-ChainDB.prototype.resetHash = function resetHash(hash, callback, emit) {
-  var self = this;
-  return this.getNextHash(hash, function(err, hash) {
+  this.get(block, function(err, entry) {
     if (err)
       return callback(err);
 
-    if (!hash)
+    if (!entry)
       return callback();
 
-    return self.remove(hash, callback, emit);
+    self.getTip(function(err, tip) {
+      if (err)
+        return callback(err);
+
+      if (!tip)
+        return callback();
+
+      batch = self.db.batch();
+
+      (function next(err, tip) {
+        if (err)
+          return done(err);
+
+        if (!tip)
+          return done();
+
+        if (tip.hash === entry.hash) {
+          batch.put('c/t', new Buffer(tip.hash, 'hex'));
+          return batch.write(callback);
+        }
+
+        batch.del('c/b/' + tip.height);
+        batch.del('c/h/' + tip.hash);
+        batch.del('c/c/' + tip.hash);
+        batch.del('c/n/' + tip.prevBlock);
+
+        if (emit)
+          emit(tip);
+
+        self.get(tip.prevBlock, next);
+      })(null, tip);
+    });
   });
 };
 
diff --git a/lib/bcoin/pool.js b/lib/bcoin/pool.js
index 30c6ee6d..b63a99e2 100644
--- a/lib/bcoin/pool.js
+++ b/lib/bcoin/pool.js
@@ -1342,7 +1342,7 @@ Pool.prototype.searchWallet = function(wallet, callback) {
       if (!height || height === -1)
         height = self.chain.height - (7 * 24 * 6);
 
-      self.chain.resetHeight(height, function(err) {
+      self.chain.reset(height, function(err) {
         if (err) {
           utils.debug('Failed to reset height: %s', err.stack + '');
           return callback(err);