[react-packager] Switch from Q to Bluebird as promises library

Summary:
This PR improves performance of `react-packager` by switching the promises library from the [Q](https://github.com/kriskowal/q) to [Bluebird](https://github.com/petkaantonov/bluebird).

[Here is the test result](https://github.com/facebook/react-native/issues/361#issuecomment-87829808) showing a noticeable difference. (2x speed improvement)

Please refer to [this issue](https://github.com/facebook/react-native/issues/361) for more details.
Closes https://github.com/facebook/react-native/pull/516
Github Author: Pilwon Huh <pilwon@gmail.com>

Test Plan:
./runJestTests
start app and click around

react-packager/__mocks__/bluebird.js

@@ -0,0 +1,5 @@
+'use strict';
+
+jest.autoMockOff();
+module.exports = require.requireActual('bluebird');
+jest.autoMockOn();

react-packager/src/DependencyResolver/haste/DependencyGraph/__tests__/DependencyGraph-test.js

@@ -10,7 +10,6 @@
 
 jest
   .dontMock('../index')
-  .dontMock('q')
   .dontMock('path')
   .dontMock('absolute-path')
   .dontMock('../docblock')

react-packager/src/DependencyResolver/haste/DependencyGraph/index.js

@@ -9,7 +9,7 @@
 'use strict';
 
 var ModuleDescriptor = require('../../ModuleDescriptor');
-var q = require('q');
+var Promise = require('bluebird');
 var fs = require('fs');
 var docblock = require('./docblock');
 var requirePattern = require('../requirePattern');
@@ -19,10 +19,10 @@ var debug = require('debug')('DependecyGraph');
 var util = require('util');
 var declareOpts = require('../../../lib/declareOpts');
 
-var readFile = q.nfbind(fs.readFile);
+var readFile = Promise.promisify(fs.readFile);
-var readDir = q.nfbind(fs.readdir);
+var readDir = Promise.promisify(fs.readdir);
-var lstat = q.nfbind(fs.lstat);
+var lstat = Promise.promisify(fs.lstat);
-var realpath = q.nfbind(fs.realpath);
+var realpath = Promise.promisify(fs.realpath);
 
 var validateOpts = declareOpts({
   roots: {
@@ -73,7 +73,7 @@ DependecyGraph.prototype.load = function() {
     return this._loading;
   }
 
-  this._loading = q.all([
+  this._loading = Promise.all([
     this._search(),
     this._buildAssetMap(),
   ]);
@@ -263,7 +263,7 @@ DependecyGraph.prototype._search = function() {
   var dir = this._queue.shift();
 
   if (dir == null) {
-    return q.Promise.resolve(this._graph);
+    return Promise.resolve(this._graph);
   }
 
   // Steps:
@@ -292,10 +292,10 @@ DependecyGraph.prototype._search = function() {
 
       var processing = self._findAndProcessPackage(files, dir)
         .then(function() {
-          return q.all(modulePaths.map(self._processModule.bind(self)));
+          return Promise.all(modulePaths.map(self._processModule.bind(self)));
         });
 
-      return q.all([
+      return Promise.all([
         processing,
         self._search()
       ]);
@@ -324,7 +324,7 @@ DependecyGraph.prototype._findAndProcessPackage = function(files, root) {
   if (packagePath != null) {
     return this._processPackage(packagePath);
   } else {
-    return q();
+    return Promise.resolve();
   }
 };
 
@@ -338,7 +338,7 @@ DependecyGraph.prototype._processPackage = function(packagePath) {
         packageJson = JSON.parse(content);
       } catch (e) {
         debug('WARNING: malformed package.json: ', packagePath);
-        return q();
+        return Promise.resolve();
       }
 
       if (packageJson.name == null) {
@@ -346,7 +346,7 @@ DependecyGraph.prototype._processPackage = function(packagePath) {
           'WARNING: package.json `%s` is missing a name field',
           packagePath
         );
-        return q();
+        return Promise.resolve();
       }
 
       packageJson._root = packageRoot;
@@ -556,7 +556,7 @@ DependecyGraph.prototype._getAbsolutePath = function(filePath) {
 
 DependecyGraph.prototype._buildAssetMap = function() {
   if (this._assetRoots == null || this._assetRoots.length === 0) {
-    return q();
+    return Promise.resolve();
   }
 
   this._assetMap = Object.create(null);
@@ -640,13 +640,13 @@ function withExtJs(file) {
 
 function handleBrokenLink(e) {
   debug('WARNING: error stating, possibly broken symlink', e.message);
-  return q();
+  return Promise.resolve();
 }
 
 function readAndStatDir(dir) {
   return readDir(dir)
     .then(function(files){
-      return q.all(files.map(function(filePath) {
+      return Promise.all(files.map(function(filePath) {
         return realpath(path.join(dir, filePath)).catch(handleBrokenLink);
       }));
     }).then(function(files) {
@@ -660,7 +660,7 @@ function readAndStatDir(dir) {
 
       return [
         files,
-        q.all(stats),
+        Promise.all(stats),
       ];
     });
 }
@@ -676,7 +676,7 @@ function buildAssetMap(roots, processAsset) {
     var root = queue.shift();
 
     if (root == null) {
-      return q();
+      return Promise.resolve();
     }
 
     return readAndStatDir(root).spread(function(files, stats) {

react-packager/src/DependencyResolver/haste/__tests__/HasteDependencyResolver-test.js

@@ -13,7 +13,7 @@ jest.dontMock('../')
     .dontMock('../requirePattern')
     .setMock('../../ModuleDescriptor', function(data) {return data;});
 
-var q = require('q');
+var Promise = require('bluebird');
 
 describe('HasteDependencyResolver', function() {
   var HasteDependencyResolver;
@@ -41,7 +41,7 @@ describe('HasteDependencyResolver', function() {
         return deps;
       });
       depGraph.load.mockImpl(function() {
-        return q();
+        return Promise.resolve();
       });
 
       return depResolver.getDependencies('/root/index.js', { dev: false })
@@ -101,7 +101,7 @@ describe('HasteDependencyResolver', function() {
         return deps;
       });
       depGraph.load.mockImpl(function() {
-        return q();
+        return Promise.resolve();
       });
 
       return depResolver.getDependencies('/root/index.js', { dev: true })
@@ -162,7 +162,7 @@ describe('HasteDependencyResolver', function() {
         return deps;
       });
       depGraph.load.mockImpl(function() {
-        return q();
+        return Promise.resolve();
       });
 
       return depResolver.getDependencies('/root/index.js', { dev: false })

react-packager/src/DependencyResolver/node/index.js

@@ -8,7 +8,7 @@
  */
 'use strict';
 
-var Promise = require('q').Promise;
+var Promise = require('bluebird');
 var ModuleDescriptor = require('../ModuleDescriptor');
 
 var mdeps = require('module-deps');

react-packager/src/FileWatcher/index.js

@@ -10,12 +10,10 @@
 
 var EventEmitter  = require('events').EventEmitter;
 var sane = require('sane');
-var q = require('q');
+var Promise = require('bluebird');
 var util = require('util');
 var exec = require('child_process').exec;
 
-var Promise = q.Promise;
-
 var detectingWatcherClass = new Promise(function(resolve) {
   exec('which watchman', function(err, out) {
     if (err || out.length === 0) {
@@ -41,7 +39,7 @@ function FileWatcher(rootConfigs) {
 
   fileWatcher = this;
 
-  this._loading = q.all(
+  this._loading = Promise.all(
     rootConfigs.map(createWatcher)
   ).then(function(watchers) {
     watchers.forEach(function(watcher) {
@@ -59,7 +57,7 @@ util.inherits(FileWatcher, EventEmitter);
 FileWatcher.prototype.end = function() {
   return this._loading.then(function(watchers) {
     watchers.forEach(function(watcher) {
-      return q.ninvoke(watcher, 'close');
+      return Promise.promisify(watcher.close, watcher)();
     });
   });
 };
@@ -88,7 +86,7 @@ function createWatcher(rootConfig) {
 FileWatcher.createDummyWatcher = function() {
   var ev = new EventEmitter();
   ev.end = function() {
-    return q();
+    return Promise.resolve();
   };
   return ev;
 };

react-packager/src/JSTransformer/Cache.js

@@ -14,12 +14,10 @@ var declareOpts = require('../lib/declareOpts');
 var fs = require('fs');
 var isAbsolutePath = require('absolute-path');
 var path = require('path');
-var q = require('q');
+var Promise = require('bluebird');
 var tmpdir = require('os').tmpDir();
 var version = require('../../../../package.json').version;
 
-var Promise = q.Promise;
-
 var validateOpts = declareOpts({
   resetCache: {
     type: 'boolean',
@@ -74,7 +72,7 @@ Cache.prototype._set = function(filepath, loaderPromise) {
   this._data[filepath] = loaderPromise.then(function(data) {
     return [
       data,
-      q.nfbind(fs.stat)(filepath)
+      Promise.promisify(fs.stat)(filepath)
     ];
   }).spread(function(data, stat) {
     this._persistEventually();
@@ -105,13 +103,13 @@ Cache.prototype._persistCache = function() {
   var data = this._data;
   var cacheFilepath = this._cacheFilePath;
 
-  this._persisting = q.all(_.values(data))
+  this._persisting = Promise.all(_.values(data))
     .then(function(values) {
       var json = Object.create(null);
       Object.keys(data).forEach(function(key, i) {
         json[key] = values[i];
       });
-      return q.nfbind(fs.writeFile)(cacheFilepath, JSON.stringify(json));
+      return Promise.promisify(fs.writeFile)(cacheFilepath, JSON.stringify(json));
     })
     .then(function() {
       this._persisting = null;

react-packager/src/JSTransformer/__tests__/Cache-test.js

@@ -15,7 +15,7 @@ jest
   .dontMock('crypto')
   .dontMock('../Cache');
 
-var q = require('q');
+var Promise = require('bluebird');
 
 describe('JSTransformer Cache', function() {
   var Cache;
@@ -32,7 +32,7 @@ describe('JSTransformer Cache', function() {
     it('calls loader callback for uncached file', function() {
       var cache = new Cache({projectRoots: ['/rootDir']});
       var loaderCb = jest.genMockFn().mockImpl(function() {
-        return q();
+        return Promise.resolve();
       });
       cache.get('/rootDir/someFile', loaderCb);
       expect(loaderCb).toBeCalledWith('/rootDir/someFile');
@@ -48,7 +48,7 @@ describe('JSTransformer Cache', function() {
       });
       var cache = new Cache({projectRoots: ['/rootDir']});
       var loaderCb = jest.genMockFn().mockImpl(function() {
-        return q('lol');
+        return Promise.resolve('lol');
       });
       return cache.get('/rootDir/someFile', loaderCb).then(function(value) {
         expect(value).toBe('lol');
@@ -65,7 +65,7 @@ describe('JSTransformer Cache', function() {
       });
       var cache = new Cache({projectRoots: ['/rootDir']});
       var loaderCb = jest.genMockFn().mockImpl(function() {
-        return q('lol');
+        return Promise.resolve('lol');
       });
       return cache.get('/rootDir/someFile', loaderCb).then(function() {
         var shouldNotBeCalled = jest.genMockFn();
@@ -152,7 +152,7 @@ describe('JSTransformer Cache', function() {
 
       var cache = new Cache({projectRoots: ['/rootDir']});
       var loaderCb = jest.genMockFn().mockImpl(function() {
-        return q('new value');
+        return Promise.resolve('new value');
       });
 
       return cache.get('/rootDir/someFile', loaderCb).then(function(value) {
@@ -193,13 +193,13 @@ describe('JSTransformer Cache', function() {
 
       var cache = new Cache({projectRoots: ['/rootDir']});
       cache.get('/rootDir/bar', function() {
-        return q('bar value');
+        return Promise.resolve('bar value');
       });
       cache.get('/rootDir/foo', function() {
-        return q('foo value');
+        return Promise.resolve('foo value');
       });
       cache.get('/rootDir/baz', function() {
-        return q('baz value');
+        return Promise.resolve('baz value');
       });
 
       jest.runAllTicks();

react-packager/src/JSTransformer/index.js

@@ -9,14 +9,13 @@
 'use strict';
 
 var fs = require('fs');
-var q = require('q');
+var Promise = require('bluebird');
 var Cache = require('./Cache');
-var _ = require('underscore');
 var workerFarm = require('worker-farm');
 var declareOpts = require('../lib/declareOpts');
 var util = require('util');
 
-var readFile = q.nfbind(fs.readFile);
+var readFile = Promise.promisify(fs.readFile);
 
 module.exports = Transformer;
 Transformer.TransformError = TransformError;
@@ -63,12 +62,14 @@ function Transformer(options) {
     });
 
   if (options.transformModulePath == null) {
-    this._failedToStart = q.Promise.reject(new Error('No transfrom module'));
+    this._failedToStart = Promise.reject(new Error('No transfrom module'));
   } else {
     this._workers = workerFarm(
       {autoStart: true, maxConcurrentCallsPerWorker: 1},
       options.transformModulePath
     );
+
+    this._transform = Promise.promisify(this._workers);
   }
 }
 
@@ -86,13 +87,13 @@ Transformer.prototype.loadFileAndTransform = function(filePath) {
     return this._failedToStart;
   }
 
-  var workers = this._workers;
+  var transform = this._transform;
   return this._cache.get(filePath, function() {
     return readFile(filePath)
       .then(function(buffer) {
         var sourceCode = buffer.toString();
 
-        return q.nfbind(workers)({
+        return transform({
           sourceCode: sourceCode,
           filename: filePath,
         }).then(

react-packager/src/Packager/__tests__/Packager-test.js

@@ -11,13 +11,12 @@
 jest
   .setMock('worker-farm', function() { return function() {};})
   .dontMock('path')
-  .dontMock('q')
   .dontMock('os')
   .dontMock('underscore')
   .setMock('uglify-js')
   .dontMock('../');
 
-var q = require('q');
+var Promise = require('bluebird');
 
 describe('Packager', function() {
   var getDependencies;
@@ -56,7 +55,7 @@ describe('Packager', function() {
     ];
 
     getDependencies.mockImpl(function() {
-      return q({
+      return Promise.resolve({
         mainModuleId: 'foo',
         dependencies: modules
       });
@@ -64,7 +63,7 @@ describe('Packager', function() {
 
     require('../../JSTransformer').prototype.loadFileAndTransform
       .mockImpl(function(path) {
-        return q({
+        return Promise.resolve({
           code: 'transformed ' + path,
           sourceCode: 'source ' + path,
           sourcePath: path

react-packager/src/Packager/index.js

@@ -11,8 +11,7 @@
 var assert = require('assert');
 var fs = require('fs');
 var path = require('path');
-var q = require('q');
+var Promise = require('bluebird');
-var Promise = require('q').Promise;
 var Transformer = require('../JSTransformer');
 var DependencyResolver = require('../DependencyResolver');
 var _ = require('underscore');
@@ -140,7 +139,7 @@ Packager.prototype._transformModule = function(module) {
   var transform;
 
   if (module.isAsset) {
-    transform = q(generateAssetModule(module));
+    transform = Promise.resolve(generateAssetModule(module));
   } else {
     transform = this._transformer.loadFileAndTransform(
       path.resolve(module.path)

react-packager/src/Server/__tests__/Server-test.js

@@ -9,7 +9,6 @@
 'use strict';
 
 jest.setMock('worker-farm', function() { return function() {}; })
-    .dontMock('q')
     .dontMock('os')
     .dontMock('path')
     .dontMock('url')
@@ -21,7 +20,7 @@ jest.setMock('worker-farm', function() { return function() {}; })
     .setMock('uglify-js')
     .dontMock('../');
 
-var q = require('q');
+var Promise = require('bluebird');
 
 describe('processRequest', function() {
   var server;
@@ -36,18 +35,19 @@ describe('processRequest', function() {
   };
 
   var makeRequest = function(requestHandler, requrl) {
-    var deferred = q.defer();
+    return new Promise(function(resolve) {
-    requestHandler({
+      requestHandler(
-        url: requrl
+        { url: requrl },
-      },{
+        {
           end: function(res) {
-          deferred.resolve(res);
+            resolve(res);
           }
-      },{
+        },
+        {
           next: function() {}
         }
       );
-    return deferred.promise;
+    });
   };
 
   var invalidatorFunc = jest.genMockFunction();
@@ -60,7 +60,7 @@ describe('processRequest', function() {
     FileWatcher = require('../../FileWatcher');
 
     Packager.prototype.package = jest.genMockFunction().mockImpl(function() {
-      return q({
+      return Promise.resolve({
         getSource: function() {
           return 'this is the source';
         },
@@ -156,7 +156,7 @@ describe('processRequest', function() {
       var packageFunc = jest.genMockFunction();
       packageFunc
         .mockReturnValueOnce(
-          q({
+          Promise.resolve({
             getSource: function() {
               return 'this is the first source';
             },
@@ -164,7 +164,7 @@ describe('processRequest', function() {
           })
         )
         .mockReturnValue(
-          q({
+          Promise.resolve({
             getSource: function() {
               return 'this is the rebuilt source';
             },

react-packager/src/Server/index.js

@@ -14,7 +14,7 @@ var declareOpts = require('../lib/declareOpts');
 var FileWatcher = require('../FileWatcher');
 var Packager = require('../Packager');
 var Activity = require('../Activity');
-var q = require('q');
+var Promise = require('bluebird');
 var _ = require('underscore');
 
 module.exports = Server;
@@ -123,7 +123,7 @@ Server.prototype._rebuildPackages = function() {
   Object.keys(packages).forEach(function(key) {
     var options = getOptionsFromUrl(key);
     // Wait for a previous build (if exists) to finish.
-    packages[key] = (packages[key] || q()).finally(function() {
+    packages[key] = (packages[key] || Promise.resolve()).finally(function() {
       // With finally promise callback we can't change the state of the promise
       // so we need to reassign the promise.
       packages[key] = buildPackage(options).then(function(p) {
@@ -154,7 +154,7 @@ Server.prototype._informChangeWatchers = function() {
 };
 
 Server.prototype.end = function() {
-  q.all([
+  Promise.all([
     this._fileWatcher.end(),
     this._packager.kill(),
   ]);
@@ -188,7 +188,7 @@ Server.prototype._processDebugRequest = function(reqUrl, res) {
     res.end(ret);
   } else if (parts[1] === 'packages') {
     ret += '<h1> Cached Packages </h1>';
-    q.all(Object.keys(this._packages).map(function(url) {
+    Promise.all(Object.keys(this._packages).map(function(url) {
       return this._packages[url].then(function(p) {
         ret += '<div><h2>' + url + '</h2>';
         ret += p.getDebugInfo();