From d5666912d42398fb7027782f2ea600250ec21d83 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Thu, 4 Dec 2014 10:17:04 +1100
Subject: [PATCH] Add cache option to 6to5-node

---
 lib/6to5/register.js | 23 ++++++++++++++++++++++-
 package.json         | 19 ++++++++++---------
 2 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/lib/6to5/register.js b/lib/6to5/register.js
index 86035276b5..1227eca5fa 100644
--- a/lib/6to5/register.js
+++ b/lib/6to5/register.js
@@ -1,8 +1,10 @@
 require("./polyfill");
 
 var sourceMapSupport = require("source-map-support");
+var roadrunner       = require('roadrunner');
 var util             = require("./util");
 var to5              = require("./index");
+var fs               = require("fs");
 var _                = require("lodash");
 
 sourceMapSupport.install({
@@ -61,22 +63,38 @@ var transformOpts = {};
 var ignoreRegex   = /node_modules/;
 var onlyRegex;
 var whitelist     = [];
+var cache;
 var exts          = {};
 var maps          = {};
 var old           = require.extensions[".js"];
 
+var mtime = function (filename) {
+  return +fs.statSync(filename).mtime;
+};
+
 var loader = function (m, filename) {
   if ((ignoreRegex && ignoreRegex.test(filename)) || (onlyRegex && !onlyRegex.test(filename))) {
     return old.apply(this, arguments);
   }
 
-  var result = to5.transformFileSync(filename, _.extend({
+  var result;
+
+  if (cache && cache[filename].mtime === mtime(filename)) {
+    result = cache[filename];
+  }
+
+  result = result || to5.transformFileSync(filename, _.extend({
     whitelist: whitelist,
     blacklist: blacklist,
     sourceMap: true,
     modules:   "commonInterop"
   }, transformOpts));
 
+  if (cache) {
+    result.mtime = mtime(filename);
+    cache[filename] = result;
+  }
+
   maps[filename] = result.map;
 
   m._compile(result.code, filename);
@@ -108,5 +126,8 @@ module.exports = function (opts) {
 
   if (opts.extensions) hookExtensions(util.arrayify(opts.extensions));
 
+  if (opts.cache) cache = roadrunner.get('6to5');
+  if (opts.cache === false) cache = null;
+
   _.extend(transformOpts, opts);
 };
diff --git a/package.json b/package.json
index 14b88a6255..d966b77014 100644
--- a/package.json
+++ b/package.json
@@ -35,26 +35,27 @@
     "test": "make test"
   },
   "dependencies": {
+    "acorn-6to5": "0.9.1-11",
     "ast-types": "0.6.5",
+    "chokidar": "0.11.1",
     "commander": "2.5.0",
+    "es6-shim": "0.21.0",
+    "es6-symbol": "0.1.1",
+    "estraverse": "1.8.0",
+    "esutils": "1.1.6",
     "fs-readdir-recursive": "0.1.0",
     "lodash": "2.4.1",
     "mkdirp": "0.5.0",
-    "es6-shim": "0.21.0",
-    "es6-symbol": "0.1.1",
+    "private": "0.1.6",
     "regexpu": "0.3.0",
+    "roadrunner": "^1.0.4",
     "source-map": "0.1.40",
-    "chokidar": "0.11.1",
-    "source-map-support": "0.2.8",
-    "esutils": "1.1.6",
-    "acorn-6to5": "0.9.1-11",
-    "estraverse": "1.8.0",
-    "private": "0.1.6"
+    "source-map-support": "0.2.8"
   },
   "devDependencies": {
     "istanbul": "0.3.2",
     "matcha": "0.6.0",
-    "mocha": "2.0.1",
+    "mocha": "1.21.4",
     "uglify-js": "2.4.15",
     "browserify": "6.3.2",
     "rimraf": "2.2.8",