Added a reset tip routine.

lib/services/block/index.js

@@ -28,6 +28,7 @@ var BlockService = function(options) {
   this._blockCount = 0;
   this.GENESIS_HASH = constants.BITCOIN_GENESIS_HASH[this.node.network];
   this._initialSync = true;
+  this._reorgBackToBlock = null;
 };
 
 inherits(BlockService, BaseService);
@@ -167,10 +168,28 @@ BlockService.prototype.getRawBlock = function(hash, callback) {
   });
 };
 
+BlockService.prototype._reorgBackTo = function(callback) {
+  var self = this;
+  self._header.getBlockHeader(self._reorgBackToBlock, function(err, header) {
+    if (err || !header) {
+      return callback(err || new Error('Header not found to reorg back to.'));
+    }
+    log.info('Block Service: we found the block to reorg back to, commencing reorg...');
+    self._handleReorg(header.hash, callback);
+  });
+};
+
 BlockService.prototype._checkTip = function(callback) {
 
   var self = this;
 
+  log.info('Block Service: checking the saved tip...');
+
+  if (self._reorgBackToBlock) {
+    log.warn('Block Service: we were asked to reorg back to block: ' + self._reorgBackToBlock);
+    return self._reorgBackTo(callback);
+  }
+
   self._header.getBlockHeader(self._tip.height, function(err, header) {
 
     if (err) {
@@ -209,8 +228,8 @@ BlockService.prototype._findCommonAncestor = function(callback) {
       return headers.get(hash);
     }, function(next) {
       self._getBlock(hash, function(err, block) {
-        if(err) {
-          return next(err);
+        if(err || !block) {
+          return next(err || new Error('block must be found in order to find common ancestor.'));
         }
         hash = bcoin.util.revHex(block.prevBlock);
         next();
@@ -224,6 +243,85 @@ BlockService.prototype._findCommonAncestor = function(callback) {
   });
 };
 
+BlockService.prototype._resetTip = function(callback) {
+  var self = this;
+
+  if (!self._tipResetNeeded) {
+    return callback();
+  }
+
+  self._tipResetNeeded = false;
+
+  log.warn('Block Service: resetting tip due to a non-existent tip block...');
+
+  var block;
+  var header = self._header.getLastHeader();
+  var height = header.height;
+
+  self._header.getAllHeaders(function(err, headers) {
+
+    if (err || !headers) {
+      return callback(err || new Error('headers required'));
+    }
+
+    log.info('Block Service: retrieved all the headers for lookups');
+    async.until(function() {
+
+      return block;
+
+    }, function(next) {
+
+      self._getBlock(header.hash, function(err, _block) {
+
+        if (err) {
+          return callback(err);
+        }
+
+	if (!_block) {
+          log.warn('Block Service: block: ' + header.hash + ' was not found, proceeding to older blocks.');
+	}
+
+        block = _block;
+        header = headers.getIndex(--height);
+        assert(header, 'Header not found for reset.');
+
+        if (!block) {
+          log.warn('Block Service: trying block: ' + header.hash);
+        }
+
+        next();
+
+      });
+
+    }, function(err) {
+
+      if (err || !block) {
+        return callback(err ||
+          new Error('Block Service: none of the blocks from the headers match what is already indexed in the block service.'));
+      }
+      self._setTip({ hash: block.rhash(), height: height + 1 });
+      callback();
+    });
+
+  });
+};
+
+BlockService.prototype._performSanityCheck = function(tip, callback) {
+
+  var self = this;
+  // is our tip saved in our database? If not, then find the latest block that is in
+  // in our database and set the tip to that
+  self._getBlock(tip.hash, function(err, block) {
+    if (err) {
+      return callback(err);
+    }
+    if (block) {
+      return callback(null, tip);
+    }
+    return callback(null, false);
+  });
+};
+
 BlockService.prototype.start = function(callback) {
 
   var self = this;
@@ -243,13 +341,23 @@ BlockService.prototype.start = function(callback) {
       return callback(err);
     }
 
-    self._blockProcessor = async.queue(self._onBlock.bind(self));
+    self._performSanityCheck(tip, function(err, tip) {
 
-    self._setListeners();
-    assert(tip.height >= 0, 'tip is not initialized');
-    self._setTip(tip);
-    self._bus = self.node.openBus({remoteAddress: 'localhost-block'});
-    callback();
+      if (err) {
+        return callback(err);
+      }
+
+      if (!tip) {
+        self._tipResetNeeded = true;
+      }
+
+      self._blockProcessor = async.queue(self._onBlock.bind(self));
+      self._setListeners();
+      self._setTip(tip);
+      self._bus = self.node.openBus({remoteAddress: 'localhost-block'});
+
+      callback();
+    });
 
   });
 
@@ -410,21 +518,26 @@ BlockService.prototype.onHeaders = function(callback) {
 
   var self = this;
 
-  async.retry(function(next) {
+  self._resetTip(function(err) {
+    if (err) {
+      return callback(err);
+    }
+    async.retry(function(next) {
 
-    next(self._blockProcessor.length() !== 0);
+      next(self._blockProcessor.length() !== 0);
 
-  }, function() {
+    }, function() {
 
-    self._checkTip(function(err) {
+      self._checkTip(function(err) {
 
-      if(err) {
-        return callback(err);
-      }
+        if(err) {
+          return callback(err);
+        }
 
-      self._startSync();
-      callback();
+        self._startSync();
+        callback();
 
+      });
     });
   });