chain: more refactoring.

lib/blockchain/chain.js

@@ -1210,8 +1210,7 @@ Chain.prototype.add = co(function* add(block) {
 Chain.prototype._add = co(function* add(block) {
   var ret = new VerifyResult();
   var initial = true;
-  var hash, height, checkpoint;
-  var orphan, entry, prev;
+  var hash, height, orphan, entry, prev;
 
   while (block) {
     hash = block.hash('hex');
@@ -1236,11 +1235,21 @@ Chain.prototype._add = co(function* add(block) {
       throw new VerifyError(block, 'duplicate', 'duplicate', 0);
     }
 
+    // If the block is already known to be
+    // an orphan, ignore it.
+    // if (this.hasOrphan(hash)) {
+    //   this.emit('orphan', block, block.getCoinbaseHeight());
+    //   throw new VerifyError(block, 'duplicate', 'duplicate', 0);
+    // }
+
+    // The orphan chain may have forked.
+    // if (this.isOrphanFork(block))
+    //   throw new VerifyError(block, 'invalid', 'bad-prevblk', 0);
+
     // If the block is already known to be
     // an orphan, ignore it.
     orphan = this.orphan.map[block.prevBlock];
     if (orphan) {
-      // The orphan chain forked.
       if (orphan.hash('hex') !== hash) {
         this.emit('fork', block,
           block.getCoinbaseHeight(),
@@ -1290,29 +1299,12 @@ Chain.prototype._add = co(function* add(block) {
     if (height > this.bestHeight)
       this.bestHeight = height;
 
-    // Verify the checkpoint.
-    if (this.options.useCheckpoints) {
-      checkpoint = this.network.checkpoints[height];
-      if (checkpoint) {
-        // Someone is either mining on top of
-        // an old block for no reason, or the
-        // consensus protocol is broken and
-        // there was a 20k+ block reorg.
-        if (hash !== checkpoint) {
-          this.logger.warning('Checkpoint mismatch!');
-
-          this.purgeOrphans();
-
-          this.emit('fork', block, height, checkpoint);
-
-          throw new VerifyError(block,
-            'checkpoint',
-            'checkpoint mismatch',
-            100);
-        }
-
-        this.emit('checkpoint', block, height);
-      }
+    // Verify a checkpoint if there is one.
+    if (!this.verifyCheckpoint(hash, height)) {
+      throw new VerifyError(block,
+        'checkpoint',
+        'checkpoint mismatch',
+        100);
     }
 
     // Explanation: we try to keep as much data
@@ -1446,6 +1438,68 @@ Chain.prototype.finish = function finish(block, entry) {
     time);
 };
 
+/**
+ * Test whether a block is a on a forked orphan chain.
+ * @private
+ * @param {Block} block
+ * @returns {Boolean}
+ */
+
+Chain.prototype.isOrphanFork = function isOrphanFork(block) {
+  var orphan = this.orphan.map[block.prevBlock];
+
+  if (!orphan)
+    return false;
+
+  assert(orphan.hash('hex') !== hash);
+
+  this.emit('fork', block,
+    block.getCoinbaseHeight(),
+    orphan.hash('hex'));
+
+  this.resolveOrphan(block.prevBlock);
+  this.storeOrphan(block);
+
+  return true;
+};
+
+/**
+ * Verify a block hash and height against the checkpoints.
+ * @private
+ * @param {Hash} hash
+ * @param {Number} height
+ * @returns {Boolean}
+ */
+
+Chain.prototype.verifyCheckpoint = function verifyCheckpoint(hash, height) {
+  var checkpoint;
+
+  if (!this.options.useCheckpoints)
+    return true;
+
+  checkpoint = this.network.checkpoints[height];
+
+  if (!checkpoint)
+    return true;
+
+  if (hash === checkpoint) {
+    this.emit('checkpoint', block, height);
+    return true;
+  }
+
+  // Someone is either mining on top of
+  // an old block for no reason, or the
+  // consensus protocol is broken and
+  // there was a 20k+ block reorg.
+  this.logger.warning('Checkpoint mismatch!');
+
+  this.purgeOrphans();
+
+  this.emit('fork', block, height, checkpoint);
+
+  return false;
+};
+
 /**
  * Store an orphan.
  * @private