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| author | Igor Minar | 2011-12-12 08:08:38 -0800 |
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| committer | Igor Minar | 2012-01-03 17:48:09 -0800 |
| commit | 9632f5c1c73c2628121d49aa2d6868fc5d8aef1a (patch) | |
| tree | cfd3aafcee3db0a9c43cf90da4160c3bd469b53a /src/Deferred.js | |
| parent | bb3be87606d2b390324765896624c37fa33fe63f (diff) | |
| download | angular.js-9632f5c1c73c2628121d49aa2d6868fc5d8aef1a.tar.bz2 | |
style(q): rename src/Deferred.js to src/service/q.js
Diffstat (limited to 'src/Deferred.js')
| -rw-r--r-- | src/Deferred.js | 387 |
1 files changed, 0 insertions, 387 deletions
diff --git a/src/Deferred.js b/src/Deferred.js deleted file mode 100644 index f0c030b0..00000000 --- a/src/Deferred.js +++ /dev/null @@ -1,387 +0,0 @@ -'use strict'; - -/** - * @ngdoc service - * @name angular.module.ng.$q - * @requires $rootScope - * - * @description - * A promise/deferred implementation inspired by [Kris Kowal's Q](https://github.com/kriskowal/q). - * - * [The CommonJS Promise proposal](http://wiki.commonjs.org/wiki/Promises) describes a promise as an - * interface for interacting with an object that represents the result of an action that is - * performed asynchronously, and may or may not be finished at any given point in time. - * - * From the perspective of dealing with error handling, deferred and promise apis are to - * asynchronous programing what `try`, `catch` and `throw` keywords are to synchronous programing. - * - * <pre> - * // for the purpose of this example let's assume that variables `$q` and `scope` are - * // available in the current lexical scope (they could have been injected or passed in). - * - * function asyncGreet(name) { - * var deferred = $q.defer(); - * - * setTimeout(function() { - * // since this fn executes async in a future turn of the event loop, we need to wrap - * // our code into an $apply call so that the model changes are properly observed. - * scope.$apply(function() { - * if (okToGreet(name)) { - * deferred.resolve('Hello, ' + name + '!'); - * } else { - * deferred.reject('Greeting ' + name + ' is not allowed.'); - * } - * }); - * }, 1000); - * - * return deferred.promise; - * } - * - * var promise = asyncGreet('Robin Hood'); - * promise.then(function(greeting) { - * alert('Success: ' + greeting); - * }, function(reason) { - * alert('Failed: ' + reason); - * ); - * </pre> - * - * At first it might not be obvious why this extra complexity is worth the trouble. The payoff - * comes in the way of - * [guarantees that promise and deferred apis make](https://github.com/kriskowal/uncommonjs/blob/master/promises/specification.md). - * - * Additionally the promise api allows for composition that is very hard to do with the - * traditional callback ([CPS](http://en.wikipedia.org/wiki/Continuation-passing_style)) approach. - * For more on this please see the [Q documentation](https://github.com/kriskowal/q) especially the - * section on serial or parallel joining of promises. - * - * - * # The Deferred API - * - * A new instance of deferred is constructed by calling `$q.defer()`. - * - * The purpose of the deferred object is to expose the associated Promise instance as well as apis - * that can be used for signaling the successful or unsuccessful completion of the task. - * - * **Methods** - * - * - `resolve(value)` – resolves the derived promise with the `value`. If the value is a rejection - * constructed via `$q.reject`, the promise will be rejected instead. - * - `reject(reason)` – rejects the derived promise with the `reason`. This is equivalent to - * resolving it with a rejection constructed via `$q.reject`. - * - * **Properties** - * - * - promise – `{Promise}` – promise object associated with this deferred. - * - * - * # The Promise API - * - * A new promise instance is created when a deferred instance is created and can be retrieved by - * calling `deferred.promise`. - * - * The purpose of the promise object is to allow for interested parties to get access to the result - * of the deferred task when it completes. - * - * **Methods** - * - * - `then(successCallback, errorCallback)` – regardless of when the promise was or will be resolved - * or rejected calls one of the success or error callbacks asynchronously as soon as the result - * is available. The callbacks are called with a single argument the result or rejection reason. - * - * This method *returns a new promise* which is resolved or rejected via the return value of the - * `successCallback` or `errorCallback`. - * - * - * # Chaining promises - * - * Because calling `then` api of a promise returns a new derived promise, it is easily possible - * to create a chain of promises: - * - * <pre> - * promiseB = promiseA.then(function(result) { - * return result + 1; - * }); - * - * // promiseB will be resolved immediately after promiseA is resolved and it's value will be - * // the result of promiseA incremented by 1 - * </pre> - * - * It is possible to create chains of any length and since a promise can be resolved with another - * promise (which will defer its resolution further), it is possible to pause/defer resolution of - * the promises at any point in the chain. This makes it possible to implement powerful apis like - * $http's response interceptors. - * - * - * # Differences between Kris Kowal's Q and $q - * - * There are three main differences: - * - * - $q is integrated with the {@link angular.module.ng.$rootScope.Scope} Scope model observation - * mechanism in angular, which means faster propagation of resolution or rejection into your - * models and avoiding unnecessary browser repaints, which would result in flickering UI. - * - $q promises are recognized by the templating engine in angular, which means that in templates - * you can treat promises attached to a scope as if they were the resulting values. - * - Q has many more features that $q, but that comes at a cost of bytes. $q is tiny, but contains - * all the important functionality needed for common async tasks. - */ -function $QProvider() { - - this.$get = ['$rootScope', '$exceptionHandler', function($rootScope, $exceptionHandler) { - return qFactory(function(callback) { - $rootScope.$evalAsync(callback); - }, $exceptionHandler); - }]; -} - - -/** - * Constructs a promise manager. - * - * @param {function(function)} nextTick Function for executing functions in the next turn. - * @param {function(...*)} exceptionHandler Function into which unexpected exceptions are passed for - * debugging purposes. - * @returns {object} Promise manager. - */ -function qFactory(nextTick, exceptionHandler) { - - /** - * @ngdoc - * @name angular.module.ng.$q#defer - * @methodOf angular.module.ng.$q - * @description - * Creates a `Deferred` object which represents a task which will finish in the future. - * - * @returns {Deferred} Returns a new instance of deferred. - */ - var defer = function() { - var pending = [], - value, deferred; - - deferred = { - - resolve: function(val) { - if (pending) { - var callbacks = pending; - pending = undefined; - value = ref(val); - - if (callbacks.length) { - nextTick(function() { - var callback; - for (var i = 0, ii = callbacks.length; i < ii; i++) { - callback = callbacks[i]; - value.then(callback[0], callback[1]); - } - }); - } - } - }, - - - reject: function(reason) { - deferred.resolve(reject(reason)); - }, - - - promise: { - then: function(callback, errback) { - var result = defer(); - - var wrappedCallback = function(value) { - try { - result.resolve((callback || defaultCallback)(value)); - } catch(e) { - exceptionHandler(e); - result.reject(e); - } - }; - - var wrappedErrback = function(reason) { - try { - result.resolve((errback || defaultErrback)(reason)); - } catch(e) { - exceptionHandler(e); - result.reject(e); - } - }; - - if (pending) { - pending.push([wrappedCallback, wrappedErrback]); - } else { - value.then(wrappedCallback, wrappedErrback); - } - - return result.promise; - } - } - }; - - return deferred; - }; - - - var ref = function(value) { - if (value && value.then) return value; - return { - then: function(callback) { - var result = defer(); - nextTick(function() { - result.resolve(callback(value)); - }); - return result.promise; - } - }; - }; - - - /** - * @ngdoc - * @name angular.module.ng.$q#reject - * @methodOf angular.module.ng.$q - * @description - * Creates a promise that is resolved as rejected with the specified `reason`. This api should be - * used to forward rejection in a chain of promises. If you are dealing with the last promise in - * a promise chain, you don't need to worry about it. - * - * When comparing deferreds/promises to the familiar behavior of try/catch/throw, think of - * `reject` as the `throw` keyword in JavaScript. This also means that if you "catch" an error via - * a promise error callback and you want to forward the error to the promise derived from the - * current promise, you have to "rethrow" the error by returning a rejection constructed via - * `reject`. - * - * <pre> - * promiseB = promiseA.then(function(result) { - * // success: do something and resolve promiseB - * // with the old or a new result - * return result; - * }, function(reason) { - * // error: handle the error if possible and - * // resolve promiseB with newPromiseOrValue, - * // otherwise forward the rejection to promiseB - * if (canHandle(reason)) { - * // handle the error and recover - * return newPromiseOrValue; - * } - * return $q.reject(reason); - * }); - * </pre> - * - * @param {*} reason Constant, message, exception or an object representing the rejection reason. - * @returns {Promise} Returns a promise that was already resolved as rejected with the `reason`. - */ - var reject = function(reason) { - return { - then: function(callback, errback) { - var result = defer(); - nextTick(function() { - result.resolve(errback(reason)); - }); - return result.promise; - } - }; - }; - - - /** - * @ngdoc - * @name angular.module.ng.$q#when - * @methodOf angular.module.ng.$q - * @description - * Wraps an object that might be a value or a (3rd party) then-able promise into a $q promise. - * This is useful when you are dealing with on object that might or might not be a promise, or if - * the promise comes from a source that can't be trusted. - * - * @param {*} value Value or a promise - * @returns {Promise} Returns a single promise that will be resolved with an array of values, - * each value coresponding to the promise at the same index in the `promises` array. If any of - * the promises is resolved with a rejection, this resulting promise will be resolved with the - * same rejection. - */ - var when = function(value, callback, errback) { - var result = defer(), - done; - - var wrappedCallback = function(value) { - try { - return (callback || defaultCallback)(value); - } catch (e) { - exceptionHandler(e); - return reject(e); - } - }; - - var wrappedErrback = function(reason) { - try { - return (errback || defaultErrback)(reason); - } catch (e) { - exceptionHandler(e); - return reject(e); - } - }; - - nextTick(function() { - ref(value).then(function(value) { - if (done) return; - done = true; - result.resolve(ref(value).then(wrappedCallback, wrappedErrback)); - }, function(reason) { - if (done) return; - done = true; - result.resolve(wrappedErrback(reason)); - }); - }); - - return result.promise; - }; - - - function defaultCallback(value) { - return value; - } - - - function defaultErrback(reason) { - return reject(reason); - } - - - /** - * @ngdoc - * @name angular.module.ng.$q#all - * @methodOf angular.module.ng.$q - * @description - * Combines multiple promises into a single promise that is resolved when all of the input - * promises are resolved. - * - * @param {Array.<Promise>} promises An array of promises. - * @returns {Promise} Returns a single promise that will be resolved with an array of values, - * each value coresponding to the promise at the same index in the `promises` array. If any of - * the promises is resolved with a rejection, this resulting promise will be resolved with the - * same rejection. - */ - function all(promises) { - var deferred = defer(), - counter = promises.length, - results = []; - - forEach(promises, function(promise, index) { - promise.then(function(value) { - if (index in results) return; - results[index] = value; - if (!(--counter)) deferred.resolve(results); - }, function(reason) { - if (index in results) return; - deferred.reject(reason); - }); - }); - - return deferred.promise; - } - - return { - defer: defer, - reject: reject, - when: when, - all: all - }; -} |
