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q.js
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q.js
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// vim:ts=4:sts=4:sw=4:
/*!
*
* Copyright 2009-2012 Kris Kowal under the terms of the MIT
* license found at http://github.com/kriskowal/q/raw/master/LICENSE
*
* With parts by Tyler Close
* Copyright 2007-2009 Tyler Close under the terms of the MIT X license found
* at http://www.opensource.org/licenses/mit-license.html
* Forked at ref_send.js version: 2009-05-11
*
* With parts by Mark Miller
* Copyright (C) 2011 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
(function (definition) {
// Turn off strict mode for this function so we can assign to global.Q
/*jshint strict: false*/
// This file will function properly as a <script> tag, or a module
// using CommonJS and NodeJS or RequireJS module formats. In
// Common/Node/RequireJS, the module exports the Q API and when
// executed as a simple <script>, it creates a Q global instead.
// Montage Require
if (typeof bootstrap === "function") {
bootstrap("promise", definition);
// CommonJS
} else if (typeof exports === "object") {
module.exports = definition();
// RequireJS
} else if (typeof define === "function") {
define(definition);
// SES (Secure EcmaScript)
} else if (typeof ses !== "undefined") {
if (!ses.ok()) {
return;
} else {
ses.makeQ = definition;
}
// <script>
} else {
Q = definition();
}
})(function () {
"use strict";
// All code after this point will be filtered from stack traces reported
// by Q.
var qStartingLine = captureLine();
var qFileName;
// shims
// used for fallback "defend" and in "allResolved"
var noop = function () {};
// for the security conscious, defend may be a deep freeze as provided
// by cajaVM. Otherwise we try to provide a shallow freeze just to
// discourage promise changes that are not compatible with secure
// usage. If Object.freeze does not exist, fall back to doing nothing
// (no op).
var defend = Object.freeze || noop;
if (typeof cajaVM !== "undefined") {
defend = cajaVM.def;
}
// use the fastest possible means to execute a task in a future turn
// of the event loop.
var nextTick;
if (typeof process !== "undefined") {
// node
nextTick = process.nextTick;
} else if (typeof setImmediate === "function") {
// In IE10, or use https://github.com/NobleJS/setImmediate
nextTick = setImmediate;
} else if (typeof MessageChannel !== "undefined") {
// modern browsers
// http://www.nonblocking.io/2011/06/windownexttick.html
var channel = new MessageChannel();
// linked list of tasks (single, with head node)
var head = {}, tail = head;
channel.port1.onmessage = function () {
head = head.next;
var task = head.task;
delete head.task;
task();
};
nextTick = function (task) {
tail = tail.next = {task: task};
channel.port2.postMessage(0);
};
} else {
// old browsers
nextTick = function (task) {
setTimeout(task, 0);
};
}
// Attempt to make generics safe in the face of downstream
// modifications.
// There is no situation where this is necessary.
// If you need a security guarantee, these primordials need to be
// deeply frozen anyway, and if you don’t need a security guarantee,
// this is just plain paranoid.
// However, this does have the nice side-effect of reducing the size
// of the code by reducing x.call() to merely x(), eliminating many
// hard-to-minify characters.
// See Mark Miller’s explanation of what this does.
// http://wiki.ecmascript.org/doku.php?id=conventions:safe_meta_programming
var uncurryThis;
// I have kept both variations because the first is theoretically
// faster, if bind is available.
if (Function.prototype.bind) {
var Function_bind = Function.prototype.bind;
uncurryThis = Function_bind.bind(Function_bind.call);
} else {
uncurryThis = function (f) {
return function () {
return f.call.apply(f, arguments);
};
};
}
var array_slice = uncurryThis(Array.prototype.slice);
var array_reduce = uncurryThis(
Array.prototype.reduce || function (callback, basis) {
var index = 0,
length = this.length;
// concerning the initial value, if one is not provided
if (arguments.length === 1) {
// seek to the first value in the array, accounting
// for the possibility that is is a sparse array
do {
if (index in this) {
basis = this[index++];
break;
}
if (++index >= length) {
throw new TypeError();
}
} while (1);
}
// reduce
for (; index < length; index++) {
// account for the possibility that the array is sparse
if (index in this) {
basis = callback(basis, this[index], index);
}
}
return basis;
}
);
var array_indexOf = uncurryThis(
Array.prototype.indexOf || function (value) {
// not a very good shim, but good enough for our one use of it
for (var i = 0; i < this.length; i++) {
if (this[i] === value) {
return i;
}
}
return -1;
}
);
var array_map = uncurryThis(
Array.prototype.map || function (callback, thisp) {
var self = this;
var collect = [];
array_reduce(self, function (undefined, value, index) {
collect.push(callback.call(thisp, value, index, self));
}, void 0);
return collect;
}
);
var object_create = Object.create || function (prototype) {
function Type() { }
Type.prototype = prototype;
return new Type();
};
var object_keys = Object.keys || function (object) {
var keys = [];
for (var key in object) {
keys.push(key);
}
return keys;
};
var object_toString = Object.prototype.toString;
// generator related shims
function isStopIteration(exception) {
return (
object_toString(exception) === "[object StopIteration]" ||
exception instanceof QReturnValue
);
}
var QReturnValue;
if (typeof ReturnValue !== "undefined") {
QReturnValue = ReturnValue;
} else {
QReturnValue = function (value) {
this.value = value;
};
}
// long stack traces
var STACK_JUMP_SEPARATOR = "From previous event:";
function makeStackTraceLong(error, promise) {
// If possible (that is, if in V8), transform the error stack
// trace by removing Node and Q cruft, then concatenating with
// the stack trace of the promise we are ``done``ing. See #57.
if (promise.stack &&
typeof error === "object" &&
error !== null &&
error.stack &&
error.stack.indexOf(STACK_JUMP_SEPARATOR) === -1
) {
error.stack = filterStackString(error.stack) +
"\n" + STACK_JUMP_SEPARATOR + "\n" +
filterStackString(promise.stack);
}
}
function filterStackString(stackString) {
var lines = stackString.split("\n");
var desiredLines = [];
for (var i = 0; i < lines.length; ++i) {
var line = lines[i];
if (!isInternalFrame(line) && !isNodeFrame(line)) {
desiredLines.push(line);
}
}
return desiredLines.join("\n");
}
function isNodeFrame(stackLine) {
return stackLine.indexOf("(module.js:") !== -1 ||
stackLine.indexOf("(node.js:") !== -1;
}
function isInternalFrame(stackLine) {
var pieces = /at .+ \((.*):(\d+):\d+\)/.exec(stackLine);
if (!pieces) {
return false;
}
var fileName = pieces[1];
var lineNumber = pieces[2];
return fileName === qFileName &&
lineNumber >= qStartingLine &&
lineNumber <= qEndingLine;
}
// discover own file name and line number range for filtering stack
// traces
function captureLine() {
if (Error.captureStackTrace) {
var fileName, lineNumber;
var oldPrepareStackTrace = Error.prepareStackTrace;
Error.prepareStackTrace = function (error, frames) {
fileName = frames[1].getFileName();
lineNumber = frames[1].getLineNumber();
};
// teases call of temporary prepareStackTrace
// JSHint and Closure Compiler generate known warnings here
/*jshint expr: true */
new Error().stack;
Error.prepareStackTrace = oldPrepareStackTrace;
qFileName = fileName;
return lineNumber;
}
}
function deprecate(callback, name, alternative) {
return function () {
if (typeof console !== "undefined" && typeof console.warn === "function") {
console.warn(name + " is deprecated, use " + alternative + " instead.", new Error("").stack);
}
return callback.apply(callback, arguments);
};
}
// end of shims
// beginning of real work
/**
* Creates fulfilled promises from non-promises,
* Passes Q promises through,
* Coerces CommonJS/Promises/A+ promises to Q promises.
*/
function Q(value) {
return resolve(value);
}
/**
* Performs a task in a future turn of the event loop.
* @param {Function} task
*/
Q.nextTick = nextTick;
/**
* Constructs a {promise, resolve} object.
*
* The resolver is a callback to invoke with a more resolved value for the
* promise. To fulfill the promise, invoke the resolver with any value that is
* not a function. To reject the promise, invoke the resolver with a rejection
* object. To put the promise in the same state as another promise, invoke the
* resolver with that other promise.
*/
Q.defer = defer;
function defer() {
// if "pending" is an "Array", that indicates that the promise has not yet
// been resolved. If it is "undefined", it has been resolved. Each
// element of the pending array is itself an array of complete arguments to
// forward to the resolved promise. We coerce the resolution value to a
// promise using the ref promise because it handles both fully
// resolved values and other promises gracefully.
var pending = [], progressListeners = [], value;
var deferred = object_create(defer.prototype);
var promise = object_create(makePromise.prototype);
promise.promiseDispatch = function (resolve, op, operands) {
var args = array_slice(arguments);
if (pending) {
pending.push(args);
if (op === "when" && operands[1]) { // progress operand
progressListeners.push(operands[1]);
}
} else {
nextTick(function () {
value.promiseDispatch.apply(value, args);
});
}
};
promise.valueOf = function () {
if (pending) {
return promise;
}
return value.valueOf();
};
if (Error.captureStackTrace) {
Error.captureStackTrace(promise, defer);
// Reify the stack into a string by using the accessor; this prevents
// memory leaks as per GH-111. At the same time, cut off the first line;
// it's always just "[object Promise]\n", as per the `toString`.
promise.stack = promise.stack.substring(promise.stack.indexOf("\n") + 1);
}
function become(resolvedValue) {
if (!pending) {
return;
}
value = resolve(resolvedValue);
array_reduce(pending, function (undefined, pending) {
nextTick(function () {
value.promiseDispatch.apply(value, pending);
});
}, void 0);
pending = void 0;
progressListeners = void 0;
}
defend(promise);
deferred.promise = promise;
deferred.resolve = become;
deferred.fulfill = function (value) {
become(fulfill(value));
};
deferred.reject = function (exception) {
become(reject(exception));
};
deferred.notify = function (progress) {
if (pending) {
array_reduce(progressListeners, function (undefined, progressListener) {
nextTick(function () {
progressListener(progress);
});
}, void 0);
}
};
return deferred;
}
/**
* Creates a Node-style callback that will resolve or reject the deferred
* promise.
* @returns a nodeback
*/
defer.prototype.makeNodeResolver = function () {
var self = this;
return function (error, value) {
if (error) {
self.reject(error);
} else if (arguments.length > 2) {
self.resolve(array_slice(arguments, 1));
} else {
self.resolve(value);
}
};
};
/**
* @param makePromise {Function} a function that returns nothing and accepts
* the resolve, reject, and notify functions for a deferred.
* @returns a promise that may be resolved with the given resolve and reject
* functions, or rejected by a thrown exception in makePromise
*/
Q.promise = promise;
function promise(makePromise) {
var deferred = defer();
fcall(
makePromise,
deferred.resolve,
deferred.reject,
deferred.notify
).fail(deferred.reject);
return deferred.promise;
}
/**
* Constructs a Promise with a promise descriptor object and optional fallback
* function. The descriptor contains methods like when(rejected), get(name),
* put(name, value), post(name, args), and delete(name), which all
* return either a value, a promise for a value, or a rejection. The fallback
* accepts the operation name, a resolver, and any further arguments that would
* have been forwarded to the appropriate method above had a method been
* provided with the proper name. The API makes no guarantees about the nature
* of the returned object, apart from that it is usable whereever promises are
* bought and sold.
*/
Q.makePromise = makePromise;
function makePromise(descriptor, fallback, valueOf, exception) {
if (fallback === void 0) {
fallback = function (op) {
return reject(new Error("Promise does not support operation: " + op));
};
}
var promise = object_create(makePromise.prototype);
promise.promiseDispatch = function (resolve, op, args) {
var result;
try {
if (descriptor[op]) {
result = descriptor[op].apply(promise, args);
} else {
result = fallback.call(promise, op, args);
}
} catch (exception) {
result = reject(exception);
}
if (resolve) {
resolve(result);
}
};
if (valueOf) {
promise.valueOf = valueOf;
}
if (exception) {
promise.exception = exception;
}
defend(promise);
return promise;
}
// provide thenables, CommonJS/Promises/A
makePromise.prototype.then = function (fulfilled, rejected, progressed) {
return when(this, fulfilled, rejected, progressed);
};
makePromise.prototype.thenResolve = function (value) {
return when(this, function () { return value; });
};
// Chainable methods
array_reduce(
[
"isResolved", "isFulfilled", "isRejected",
"dispatch",
"when", "spread",
"get", "put", "set", "del", "delete",
"post", "send",
"invoke", // XXX deprecated
"keys",
"fapply", "fcall", "fbind",
"all", "allResolved",
"timeout", "delay",
"catch", "finally", "fail", "fin", "progress", "done",
"nfcall", "nfapply", "nfbind",
"ncall", "napply", "nbind",
"npost", "nsend",
"ninvoke", // XXX deprecated
"nodeify"
],
function (undefined, name) {
makePromise.prototype[name] = function () {
return Q[name].apply(
Q,
[this].concat(array_slice(arguments))
);
};
},
void 0
);
makePromise.prototype.toSource = function () {
return this.toString();
};
makePromise.prototype.toString = function () {
return "[object Promise]";
};
defend(makePromise.prototype);
/**
* If an object is not a promise, it is as "near" as possible.
* If a promise is rejected, it is as "near" as possible too.
* If it’s a fulfilled promise, the fulfillment value is nearer.
* If it’s a deferred promise and the deferred has been resolved, the
* resolution is "nearer".
* @param object
* @returns most resolved (nearest) form of the object
*/
Q.nearer = valueOf;
function valueOf(value) {
if (isPromise(value)) {
return value.valueOf();
}
return value;
}
/**
* @returns whether the given object is a promise.
* Otherwise it is a fulfilled value.
*/
Q.isPromise = isPromise;
function isPromise(object) {
return object && typeof object.promiseDispatch === "function";
}
Q.isPromiseAlike = isPromiseAlike;
function isPromiseAlike(object) {
return object && typeof object.then === "function";
}
/**
* @returns whether the given object is a resolved promise.
*/
Q.isResolved = isResolved;
function isResolved(object) {
return isFulfilled(object) || isRejected(object);
}
/**
* @returns whether the given object is a value or fulfilled
* promise.
*/
Q.isFulfilled = isFulfilled;
function isFulfilled(object) {
return !isPromiseAlike(valueOf(object));
}
/**
* @returns whether the given object is a rejected promise.
*/
Q.isRejected = isRejected;
function isRejected(object) {
object = valueOf(object);
return isPromise(object) && 'exception' in object;
}
var rejections = [];
var errors = [];
var errorsDisplayed;
function displayErrors() {
if (
!errorsDisplayed &&
typeof window !== "undefined" &&
!window.Touch &&
window.console
) {
// This promise library consumes exceptions thrown in handlers so
// they can be handled by a subsequent promise. The rejected
// promises get added to this array when they are created, and
// removed when they are handled.
console.log("Should be empty:", errors);
}
errorsDisplayed = true;
}
/**
* Constructs a rejected promise.
* @param exception value describing the failure
*/
Q.reject = reject;
function reject(exception) {
var rejection = makePromise({
"when": function (rejected) {
// note that the error has been handled
if (rejected) {
var at = array_indexOf(rejections, this);
if (at !== -1) {
errors.splice(at, 1);
rejections.splice(at, 1);
}
}
return rejected ? rejected(exception) : reject(exception);
}
}, function fallback() {
return reject(exception);
}, function valueOf() {
return this;
}, exception);
// note that the error has not been handled
displayErrors();
rejections.push(rejection);
errors.push(exception);
return rejection;
}
/**
* Constructs a fulfilled promise for an immediate reference.
* @param value immediate reference
*/
Q.fulfill = fulfill;
function fulfill(object) {
return makePromise({
"when": function () {
return object;
},
"get": function (name) {
return object[name];
},
"set": function (name, value) {
object[name] = value;
return object;
},
"delete": function (name) {
delete object[name];
return object;
},
"post": function (name, value) {
return object[name].apply(object, value);
},
"apply": function (args) {
return object.apply(void 0, args);
},
"keys": function () {
return object_keys(object);
}
}, void 0, function valueOf() {
return object;
});
}
/**
* Constructs a promise for an immediate reference, passes promises through, or
* coerces promises from different systems.
* @param value immediate reference or promise
*/
Q.resolve = resolve;
function resolve(value) {
// If the object is already a Promise, return it directly. This enables
// the resolve function to both be used to created references from objects,
// but to tolerably coerce non-promises to promises.
if (isPromise(value)) {
return value;
}
// In order to break infinite recursion or loops between `then` and
// `resolve`, it is necessary to attempt to extract fulfilled values
// out of foreign promise implementations before attempting to wrap
// them as unresolved promises. It is my hope that other
// implementations will implement `valueOf` to synchronously extract
// the fulfillment value from their fulfilled promises. If the
// other promise library does not implement `valueOf`, the
// implementations on primordial prototypes are harmless.
value = valueOf(value);
// assimilate thenables, CommonJS/Promises/A+
if (isPromiseAlike(value)) {
return coerce(value);
} else {
return fulfill(value);
}
}
/**
* Converts thenables to Q promises.
* @param promise thenable promise
* @returns a Q promise
*/
function coerce(promise) {
var deferred = defer();
promise.then(deferred.resolve, deferred.reject, deferred.notify);
return deferred.promise;
}
/**
* Annotates an object such that it will never be
* transferred away from this process over any promise
* communication channel.
* @param object
* @returns promise a wrapping of that object that
* additionally responds to the "isDef" message
* without a rejection.
*/
Q.master = master;
function master(object) {
return makePromise({
"isDef": function () {}
}, function fallback(op, args) {
return dispatch(object, op, args);
}, function () {
return valueOf(object);
});
}
/**
* Registers an observer on a promise.
*
* Guarantees:
*
* 1. that fulfilled and rejected will be called only once.
* 2. that either the fulfilled callback or the rejected callback will be
* called, but not both.
* 3. that fulfilled and rejected will not be called in this turn.
*
* @param value promise or immediate reference to observe
* @param fulfilled function to be called with the fulfilled value
* @param rejected function to be called with the rejection exception
* @param progressed function to be called on any progress notifications
* @return promise for the return value from the invoked callback
*/
Q.when = when;
function when(value, fulfilled, rejected, progressed) {
var deferred = defer();
var done = false; // ensure the untrusted promise makes at most a
// single call to one of the callbacks
function _fulfilled(value) {
try {
return typeof fulfilled === "function" ? fulfilled(value) : value;
} catch (exception) {
return reject(exception);
}
}
function _rejected(exception) {
if (typeof rejected === "function") {
makeStackTraceLong(exception, resolvedValue);
try {
return rejected(exception);
} catch (newException) {
return reject(newException);
}
}
return reject(exception);
}
function _progressed(value) {
return typeof progressed === "function" ? progressed(value) : value;
}
var resolvedValue = resolve(value);
nextTick(function () {
resolvedValue.promiseDispatch(function (value) {
if (done) {
return;
}
done = true;
deferred.resolve(_fulfilled(value));
}, "when", [function (exception) {
if (done) {
return;
}
done = true;
deferred.resolve(_rejected(exception));
}]);
});
// Progress propagator need to be attached in the current tick.
resolvedValue.promiseDispatch(void 0, "when", [void 0, function (value) {
var newValue;
var threw = false;
try {
newValue = _progressed(value);
} catch (e) {
threw = true;
if (Q.onerror) {
Q.onerror(e);
} else {
throw e;
}
}
if (!threw) {
deferred.notify(newValue);
}
}]);
return deferred.promise;
}
/**
* Spreads the values of a promised array of arguments into the
* fulfillment callback.
* @param fulfilled callback that receives variadic arguments from the
* promised array
* @param rejected callback that receives the exception if the promise
* is rejected.
* @returns a promise for the return value or thrown exception of
* either callback.
*/
Q.spread = spread;
function spread(promise, fulfilled, rejected) {
return when(promise, function (valuesOrPromises) {
return all(valuesOrPromises).then(function (values) {
return fulfilled.apply(void 0, values);
}, rejected);
}, rejected);
}
/**
* The async function is a decorator for generator functions, turning
* them into asynchronous generators. This presently only works in
* Firefox/Spidermonkey, however, this code does not cause syntax
* errors in older engines. This code should continue to work and
* will in fact improve over time as the language improves.
*
* Decorates a generator function such that:
* - it may yield promises
* - execution will continue when that promise is fulfilled
* - the value of the yield expression will be the fulfilled value
* - it returns a promise for the return value (when the generator
* stops iterating)
* - the decorated function returns a promise for the return value
* of the generator or the first rejected promise among those
* yielded.
* - if an error is thrown in the generator, it propagates through
* every following yield until it is caught, or until it escapes
* the generator function altogether, and is translated into a
* rejection for the promise returned by the decorated generator.
* - in present implementations of generators, when a generator
* function is complete, it throws ``StopIteration``, ``return`` is
* a syntax error in the presence of ``yield``, so there is no
* observable return value. There is a proposal[1] to add support
* for ``return``, which would permit the value to be carried by a
* ``StopIteration`` instance, in which case it would fulfill the
* promise returned by the asynchronous generator. This can be
* emulated today by throwing StopIteration explicitly with a value
* property.
*
* [1]: http://wiki.ecmascript.org/doku.php?id=strawman:async_functions#reference_implementation
*
*/
Q.async = async;
function async(makeGenerator) {
return function () {
// when verb is "send", arg is a value
// when verb is "throw", arg is an exception
function continuer(verb, arg) {
var result;
try {
result = generator[verb](arg);
} catch (exception) {
if (isStopIteration(exception)) {
return exception.value;
} else {
return reject(exception);
}
}
return when(result, callback, errback);
}
var generator = makeGenerator.apply(this, arguments);
var callback = continuer.bind(continuer, "send");
var errback = continuer.bind(continuer, "throw");
return callback();
};
}
/**
* Throws a ReturnValue exception to stop an asynchronous generator.
* Only useful presently in Firefox/SpiderMonkey since generators are
* implemented.
* @param value the return value for the surrounding generator
* @throws ReturnValue exception with the value.
* @example
* Q.async(function () {
* var foo = yield getFooPromise();
* var bar = yield getBarPromise();
* Q.return(foo + bar);
* })
*/
Q['return'] = _return;
function _return(value) {
throw new QReturnValue(value);
}
/**
* The promised function decorator ensures that any promise arguments
* are resolved and passed as values (`this` is also resolved and passed
* as a value). It will also ensure that the result of a function is
* always a promise.
*
* @example
* var add = Q.promised(function (a, b) {
* return a + b;
* });
* add(Q.resolve(a), Q.resolve(B));
*
* @param {function} callback The function to decorate
* @returns {function} a function that has been decorated.
*/
Q.promised = promised;
function promised(callback) {
return function () {
return spread([this, all(arguments)], function (self, args) {
return callback.apply(self, args);
});
};
}
/**
* sends a message to a value in a future turn
* @param object* the recipient
* @param op the name of the message operation, e.g., "when",
* @param args further arguments to be forwarded to the operation
* @returns result {Promise} a promise for the result of the operation
*/
Q.dispatch = dispatch;
function dispatch(object, op, args) {
var deferred = defer();
nextTick(function () {
resolve(object).promiseDispatch(deferred.resolve, op, args);
});
return deferred.promise;
}
/**
* Constructs a promise method that can be used to safely observe resolution of
* a promise for an arbitrarily named method like "propfind" in a future turn.
*
* "dispatcher" constructs methods like "get(promise, name)" and "put(promise)".
*/
Q.dispatcher = dispatcher;
function dispatcher(op) {
return function (object) {
var args = array_slice(arguments, 1);
return dispatch(object, op, args);
};
}
/**
* Gets the value of a property in a future turn.