From d4783dabde5bdacef90ce209f03655417d346242 Mon Sep 17 00:00:00 2001
From: Chris Kleeschulte <chrisk@bitpay.com>
Date: Tue, 24 Jan 2017 09:00:19 -0500
Subject: [PATCH] Added rudimentry mempool.

---
 lib/services/address/index.js |  4 +--
 lib/services/bitcoind.js      |  9 ++++++
 lib/services/transaction.js   | 57 +++++++++++++++++++++++++++++------
 3 files changed, 59 insertions(+), 11 deletions(-)

diff --git a/lib/services/address/index.js b/lib/services/address/index.js
index 3ba26e61..c4d94193 100644
--- a/lib/services/address/index.js
+++ b/lib/services/address/index.js
@@ -221,7 +221,7 @@ AddressService.prototype.blockHandler = function(block, connectBlock, callback)
         return next();
       }
 
-      self.node.services.transaction.getTransaction(input.prevTxId.toString('hex'), function(err, tx) {
+      self.node.services.transaction.getTransaction(input.prevTxId.toString('hex'), {}, function(err, tx) {
         if(err) {
           return next(err);
         }
@@ -1073,7 +1073,7 @@ AddressService.prototype.getAddressHistory = function(addresses, options, callba
     });
   }, function(err) {
     async.mapLimit(txids, self.concurrency, function(txid, next) {
-      self.node.services.transaction.getTransaction(txid, function(err, tx) {
+      self.node.services.transaction.getTransaction(txid, options, function(err, tx) {
         if(err) {
           return next(err);
         }
diff --git a/lib/services/bitcoind.js b/lib/services/bitcoind.js
index 18fdf846..99ea7196 100644
--- a/lib/services/bitcoind.js
+++ b/lib/services/bitcoind.js
@@ -2082,6 +2082,15 @@ Bitcoin.prototype.getInfo = function(callback) {
   });
 };
 
+Bitcoin.prototype.getMempool = function(callback) {
+  this.client.getRawMemPool(function(err, res) {
+    if(err) {
+      return callback(err);
+    }
+    callback(null, res.result);
+  });
+};
+
 Bitcoin.prototype.generateBlock = function(num, callback) {
   var self = this;
   this.client.generate(num, function(err, response) {
diff --git a/lib/services/transaction.js b/lib/services/transaction.js
index 3f4c290e..f7ef48c8 100644
--- a/lib/services/transaction.js
+++ b/lib/services/transaction.js
@@ -5,9 +5,18 @@ var BaseService = require('../service');
 var inherits = require('util').inherits;
 var bitcore = require('bitcore-lib');
 
+/**
+ * The Transaction Service builds upon the Database Service and the Bitcoin Service to add additional
+ * functionality for getting information by bitcoin transaction hash/id. This includes the current
+ * bitcoin memory pool as validated by a trusted bitcoind instance.
+ * @param {Object} options
+ * @param {Node} options.node - An instance of the node
+ * @param {String} options.name - An optional name of the service
+ */
 function TransactionService(options) {
   BaseService.call(this, options);
   this.concurrency = options.concurrency || 20;
+  this._mempool = {};
   this.currentTransactions = {};
 }
 
@@ -21,16 +30,40 @@ TransactionService.dependencies = [
 TransactionService.prototype.start = function(callback) {
   var self = this;
 
-  this.store = this.node.services.db.store;
+  self.store = this.node.services.db.store;
 
-  this.node.services.db.getPrefix(this.name, function(err, prefix) {
-    if(err) {
-      return callback(err);
-    }
+  var bus = self.node.openBus();
+  bus.subscribe('bitcoind/rawtransaction');
 
-    self.prefix = prefix;
+  bus.on('bitcoind/rawtransaction', function(txHex) {
+    var tx = new bitcore.Transaction(txHex);
+    self._mempool[tx.id] = tx;
+  });
 
-    callback();
+  async.series([
+    function(next) {
+      self.node.services.bitcoind.getMempool(function(err, txs) {
+        if(err) {
+          return next(err);
+        }
+        for(var i = 0; i < txs.length; i++) {
+          self._mempool[txs[i]] = true;
+        }
+        next();
+      });
+    }, function(next) {
+      self.node.services.db.getPrefix(self.name, function(err, prefix) {
+        if(err) {
+          return callback(err);
+        }
+        self.prefix = prefix;
+        next();
+      });
+    }], function(err) {
+      if(err) {
+        return callback(err);
+      }
+      callback();
   });
 };
 
@@ -100,7 +133,7 @@ TransactionService.prototype._getInputValues = function(tx, callback) {
   }
 
   async.mapLimit(tx.inputs, this.concurrency, function(input, next) {
-    self.getTransaction(input.prevTxId.toString('hex'), function(err, prevTx) {
+    self.getTransaction(input.prevTxId.toString('hex'), {}, function(err, prevTx) {
       if(err) {
         return next(err);
       }
@@ -113,7 +146,7 @@ TransactionService.prototype._getInputValues = function(tx, callback) {
   }, callback);
 };
 
-TransactionService.prototype.getTransaction = function(txid, callback) {
+TransactionService.prototype.getTransaction = function(txid, options, callback) {
   var self = this;
 
   if(self.currentTransactions[txid]) {
@@ -122,6 +155,12 @@ TransactionService.prototype.getTransaction = function(txid, callback) {
     });
   }
 
+  if (options.queryMempool && self._mempool[txid]) {
+    return setImmediate(function() {
+      callback(null, self._mempool[txid]);
+    });
+  }
+
   var key = self._encodeTransactionKey(txid);
 
   self.node.services.db.store.get(key, function(err, buffer) {