michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
michael@0:  */
michael@0: 
michael@0: 'use strict';
michael@0: 
michael@0: /*
michael@0:  * Uses `Promise.jsm` as a core implementation, with additional sugar
michael@0:  * from previous implementation, with inspiration from `Q` and `when`
michael@0:  *
michael@0:  * https://developer.mozilla.org/en-US/docs/Mozilla/JavaScript_code_modules/Promise.jsm
michael@0:  * https://github.com/cujojs/when
michael@0:  * https://github.com/kriskowal/q
michael@0:  */
michael@0: const PROMISE_URI = 'resource://gre/modules/Promise.jsm';
michael@0: 
michael@0: getEnvironment.call(this, function ({ require, exports, module, Cu }) {
michael@0: 
michael@0: const { defer, resolve, all, reject, race } = Cu.import(PROMISE_URI, {}).Promise;
michael@0: 
michael@0: module.metadata = {
michael@0:   'stability': 'unstable'
michael@0: };
michael@0: 
michael@0: let promised = (function() {
michael@0:   // Note: Define shortcuts and utility functions here in order to avoid
michael@0:   // slower property accesses and unnecessary closure creations on each
michael@0:   // call of this popular function.
michael@0: 
michael@0:   var call = Function.call;
michael@0:   var concat = Array.prototype.concat;
michael@0: 
michael@0:   // Utility function that does following:
michael@0:   // execute([ f, self, args...]) => f.apply(self, args)
michael@0:   function execute (args) call.apply(call, args)
michael@0: 
michael@0:   // Utility function that takes promise of `a` array and maybe promise `b`
michael@0:   // as arguments and returns promise for `a.concat(b)`.
michael@0:   function promisedConcat(promises, unknown) {
michael@0:     return promises.then(function (values) {
michael@0:       return resolve(unknown)
michael@0:         .then(function (value) values.concat([value]));
michael@0:     });
michael@0:   }
michael@0: 
michael@0:   return function promised(f, prototype) {
michael@0:     /**
michael@0:     Returns a wrapped `f`, which when called returns a promise that resolves to
michael@0:     `f(...)` passing all the given arguments to it, which by the way may be
michael@0:     promises. Optionally second `prototype` argument may be provided to be used
michael@0:     a prototype for a returned promise.
michael@0: 
michael@0:     ## Example
michael@0: 
michael@0:     var promise = promised(Array)(1, promise(2), promise(3))
michael@0:     promise.then(console.log) // => [ 1, 2, 3 ]
michael@0:     **/
michael@0: 
michael@0:     return function promised() {
michael@0:       // create array of [ f, this, args... ]
michael@0:       return concat.apply([ f, this ], arguments).
michael@0:         // reduce it via `promisedConcat` to get promised array of fulfillments
michael@0:         reduce(promisedConcat, resolve([], prototype)).
michael@0:         // finally map that to promise of `f.apply(this, args...)`
michael@0:         then(execute);
michael@0:     };
michael@0:   };
michael@0: })();
michael@0: 
michael@0: exports.promised = promised;
michael@0: exports.all = all;
michael@0: exports.defer = defer;
michael@0: exports.resolve = resolve;
michael@0: exports.reject = reject;
michael@0: exports.race = race;
michael@0: exports.Promise = Promise;
michael@0: 
michael@0: });
michael@0: 
michael@0: function getEnvironment (callback) {
michael@0:   let Cu, _exports, _module, _require;
michael@0: 
michael@0:   // CommonJS / SDK
michael@0:   if (typeof(require) === 'function') {
michael@0:     Cu = require('chrome').Cu;
michael@0:     _exports = exports;
michael@0:     _module = module;
michael@0:     _require = require;
michael@0:   }
michael@0:   // JSM
michael@0:   else if (String(this).indexOf('BackstagePass') >= 0) {
michael@0:     Cu = this['Components'].utils;
michael@0:     _exports = this.Promise = {};
michael@0:     _module = { uri: __URI__, id: 'promise/core' };
michael@0:     _require = uri => {
michael@0:       let imports = {};
michael@0:       Cu.import(uri, imports);
michael@0:       return imports;
michael@0:     };
michael@0:     this.EXPORTED_SYMBOLS = ['Promise'];
michael@0:   // mozIJSSubScriptLoader.loadSubscript
michael@0:   } else if (~String(this).indexOf('Sandbox')) {
michael@0:     Cu = this['Components'].utils;
michael@0:     _exports = this;
michael@0:     _module = { id: 'promise/core' };
michael@0:     _require = uri => {};
michael@0:   }
michael@0: 
michael@0:   callback({
michael@0:     Cu: Cu,
michael@0:     exports: _exports,
michael@0:     module: _module,
michael@0:     require: _require
michael@0:   });
michael@0: }
michael@0: