From a3f8c809a0e2f60453ef0e269c01d1516b59ac63 Mon Sep 17 00:00:00 2001
From: Jonathan Rainville <rainville.jonathan@gmail.com>
Date: Thu, 10 May 2018 13:28:12 -0400
Subject: [PATCH] add queue for changes to do only one file build at the time

---
 lib/core/engine.js | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/core/engine.js b/lib/core/engine.js
index 69f22595..bef11c74 100644
--- a/lib/core/engine.js
+++ b/lib/core/engine.js
@@ -8,7 +8,8 @@ const CodeGenerator = require('../contracts/code_generator.js');
 const ServicesMonitor = require('./services_monitor.js');
 const Watch = require('../pipeline/watch.js');
 const LibraryManager = require('../versions/library_manager.js');
-let Pipeline = require('../pipeline/pipeline.js');
+const Pipeline = require('../pipeline/pipeline.js');
+const async = require('async');
 
 class Engine {
   constructor(options) {
@@ -142,11 +143,17 @@ class Engine {
       normalizeInput: this.normalizeInput,
       plugins: this.plugins
     });
+
+    const queue = async.queue((task, callback) => {
+      pipeline.build(task.abi, task.contractsJSON, task.path, callback);
+    }, 1);
+
     this.events.on('code-generator-ready', function () {
       self.events.request('code', function (abi, contractsJSON) {
         self.currentAbi = abi;
         self.contractsJSON = contractsJSON;
-        pipeline.build(abi, contractsJSON, null, function() {
+
+        queue.push({abi, contractsJSON, path: null}, () => {
           if (self.watch) {
             self.watch.restart(); // Necessary because changing a file while it is writing can stop it from being watched
           }