pool: do not request duplicate txs.

lib/net/pool.js

@@ -1469,22 +1469,10 @@ Pool.prototype.handleBlockInv = co(function* handleBlockInv(peer, hashes) {
  */
 
 Pool.prototype.handleTXInv = co(function* handleTXInv(peer, hashes) {
-  var items = [];
-  var i, hash;
-
   if (this.syncing && !this.chain.synced)
     return;
 
-  for (i = 0; i < hashes.length; i++) {
+  this.ensureTX(peer, hashes);
-    hash = hashes[i];
-
-    if (this.hasTX(hash))
-      continue;
-
-    items.push(hash);
-  }
-
-  this.getTX(peer, items);
 });
 
 /**
@@ -2184,7 +2172,7 @@ Pool.prototype._handleTX = co(function* handleTX(peer, packet) {
       'Requesting %d missing transactions (%s).',
       missing.length, peer.hostname());
 
-    this.getTX(peer, missing);
+    this.ensureTX(peer, missing);
   }
 });
 
@@ -3128,6 +3116,29 @@ Pool.prototype.hasTX = function hasTX(hash) {
   return false;
 };
 
+/**
+ * Queue a `getdata` request to be sent.
+ * Check tx existence before requesting.
+ * @param {Peer} peer
+ * @param {Hash[]} hashes
+ */
+
+Pool.prototype.ensureTX = function ensureTX(peer, hashes) {
+  var items = [];
+  var i, hash;
+
+  for (i = 0; i < hashes.length; i++) {
+    hash = hashes[i];
+
+    if (this.hasTX(hash))
+      continue;
+
+    items.push(hash);
+  }
+
+  this.getTX(peer, items);
+};
+
 /**
  * Fulfill a requested item.
  * @param {Peer} peer