getLocator. optimize height lookup.

lib/bcoin/chain.js

@@ -827,8 +827,6 @@ Chain.prototype._checkInputs = function _checkInputs(block, prev, state, callbac
 
     // Check all transactions
     utils.forEachSerial(block.txs, function(tx, next) {
-      var hash = tx.hash('hex');
-
       // Ensure tx is not double spending an output.
       if (!tx.isCoinbase()) {
         if (!tx.hasCoins()) {
@@ -1598,8 +1596,8 @@ Chain.prototype.add = function add(block, callback, force) {
 
     // Take heap snapshot for debugging.
     if (self.total % 20 === 0) {
-      bcoin.profiler.snapshot();
       utils.gc();
+      bcoin.profiler.snapshot();
     }
 
     utils.nextTick(function() {
@@ -1916,9 +1914,8 @@ Chain.prototype.getHashRange = function getHashRange(start, end, callback) {
 Chain.prototype.getLocator = function getLocator(start, callback, force) {
   var self = this;
   var hashes = [];
-  var top = this.height;
   var step = 1;
-  var i;
+  var height;
 
   var unlock = this._lock(getLocator, [start, callback], force);
   if (!unlock)
@@ -1926,67 +1923,67 @@ Chain.prototype.getLocator = function getLocator(start, callback, force) {
 
   callback = utils.wrap(callback, unlock);
 
-  function build(err, top) {
+  function getAncestor(entry, height, main, callback) {
+    if (height === 0)
+      return callback(null, { hash: network.genesis.hash, height: 0 });
+
+    if (!main)
+      return entry.getAncestorByHeight(height, callback);
+
+    return self.db.getHash(height, function(err, hash) {
+      if (err)
+        return callback(err);
+
+      if (!hash)
+        return callback();
+
+      return callback(null, { hash: hash, height: height });
+    });
+  }
+
+  if (start == null)
+    start = this.tip.hash;
+
+  return self.db.get(start, function(err, entry) {
     if (err)
       return callback(err);
 
-    i = top;
-    for (;;) {
-      hashes.push(i);
-      i = i - step;
-      if (i <= 0) {
-        if (i + step !== 0)
-          hashes.push(network.genesis.hash);
-        break;
-      }
-      if (hashes.length >= 10)
-        step *= 2;
+    if (!entry) {
+      // We could simply return `start` here,
+      // but there is no standardized "spacing"
+      // for locator hashes. Pretend this hash
+      // is our tip. This is useful for
+      // getheaders.
+      if (typeof start === 'string')
+        hashes.push(start);
+      entry = self.tip;
     }
 
-    utils.forEachSerial(hashes, function(height, next, i) {
-      if (typeof height === 'string')
-        return next();
-
-      self.db.getHash(height, function(err, hash) {
-        if (err)
-          return next(err);
-
-        assert(hash);
-
-        hashes[i] = hash;
-
-        next();
-      });
-    }, function(err) {
+    entry.isMainChain(function(err, main) {
       if (err)
         return callback(err);
-      return callback(null, hashes);
+
+      (function next(err, entry) {
+        if (err)
+          return callback(err);
+
+        if (!entry)
+          return callback(null, hashes);
+
+        hashes.push(entry.hash);
+
+        if (entry.height === 0)
+          return callback(null, hashes);
+
+        height = Math.max(entry.height - step, 0);
+
+        if (hashes.length > 10)
+          step *= 2;
+
+        getAncestor(entry, height, main, next);
+      })(null, entry);
     });
-  }
-
-  if (typeof start === 'string') {
-    return self.db.getHeight(start, function(err, top) {
-      if (err)
-        return build(err);
-
-      if (top === -1) {
-        // We could simply `return [start]` here,
-        // but there is no standardized "spacing"
-        // for locator hashes. Pretend this hash
-        // is our tip. This is useful for getheaders
-        // when not using headers-first.
-        hashes.push(start);
-        top = self.height;
-      }
-
-      return build(null, top);
-    });
-  }
-
-  if (typeof start === 'number')
-    top = start;
-
-  return build(null, top);
+  });
 };
 
 /**
@@ -2507,7 +2504,7 @@ Chain.prototype.getLocks = function getLocks(tx, flags, entry, callback) {
  */
 
 Chain.prototype.evalLocks = function evalLocks(entry, minHeight, minTime, callback) {
-  if (minHeight >= entry.height)
+  if (minHeight >= entry.height + 1)
     return utils.asyncify(callback)(null, false);
 
   if (minTime === -1)
@@ -2543,36 +2540,5 @@ Chain.prototype.checkLocks = function checkLocks(tx, flags, entry, callback) {
   });
 };
 
-/**
- * Calculate the difficulty.
- * @param {ChainBlock} entry
- * @returns {Number} Difficulty.
- */
-
-Chain.prototype.getDifficulty = function getDifficulty(entry) {
-  var shift, diff;
-
-  if (!entry) {
-    if (!this.tip)
-      return 1.0;
-    entry = this.tip;
-  }
-
-  shift = (entry.bits >>> 24) & 0xff;
-  diff = 0x0000ffff / (entry.bits & 0x00ffffff);
-
-  while (shift < 29) {
-    diff *= 256.0;
-    shift++;
-  }
-
-  while (shift > 29) {
-    diff /= 256.0;
-    shift--;
-  }
-
-  return diff;
-};
-
 return Chain;
 };

lib/bcoin/chainblock.js

@@ -172,22 +172,32 @@ ChainBlock.prototype.isMainChain = function isMainChain(callback) {
  */
 
 ChainBlock.prototype.getAncestorByHeight = function getAncestorByHeight(height, callback) {
+  var self = this;
+
   if (height < 0)
     return utils.nextTick(callback);
 
   assert(height >= 0);
   assert(height <= this.height);
 
-  return this.getAncestor(this.height - height, function(err, entry) {
+  this.isMainChain(function(err, main) {
     if (err)
       return callback(err);
 
-    if (!entry)
-      return callback();
+    if (main)
+      return self.chain.db.get(height, callback);
 
-    assert(entry.height === height);
+    return self.getAncestor(self.height - height, function(err, entry) {
+      if (err)
+        return callback(err);
 
-    return callback(null, entry);
+      if (!entry)
+        return callback();
+
+      assert(entry.height === height);
+
+      return callback(null, entry);
+    });
   });
 };
 

lib/bcoin/chaindb.js

@@ -629,6 +629,9 @@ ChainDB.prototype.isMainChain = function isMainChain(hash, callback) {
     query = hash;
   }
 
+  if (hash === this.chain.tip.hash || hash === network.genesis.hash)
+    return utils.asyncify(callback)(null, true);
+
   return this.getHeight(query, function(err, height) {
     if (err)
       return callback(err);

lib/bcoin/mempool.js

@@ -1240,22 +1240,7 @@ Mempool.prototype.getSnapshot = function getSnapshot(callback) {
  */
 
 Mempool.prototype.checkLocks = function checkLocks(tx, flags, callback) {
-  var self = this;
-  var tip = this.chain.tip;
-
-  var index = new bcoin.chainblock(this.chain, {
-    hash: constants.NULL_HASH,
-    version: tip.version,
-    prevBlock: tip.hash,
-    merkleRoot: constants.NULL_HASH,
-    ts: utils.now(),
-    bits: 0,
-    nonce: 0,
-    height: tip.height + 1,
-    chainwork: tip.chainwork
-  });
-
-  return this.chain.checkLocks(tx, flags, index, callback);
+  return this.chain.checkLocks(tx, flags, this.chain.tip, callback);
 };
 
 /**