in www/benchmarks/setImmediate.js [22:239]
(function (global, undefined) {
"use strict";
var tasks = (function () {
function Task(handler, args) {
this.handler = handler;
this.args = args;
}
Task.prototype.run = function () {
// See steps in section 5 of the spec.
if (typeof this.handler === "function") {
// Choice of `thisArg` is not in the setImmediate spec; `undefined` is in the setTimeout spec though:
// http://www.whatwg.org/specs/web-apps/current-work/multipage/timers.html
this.handler.apply(undefined, this.args);
} else {
var scriptSource = "" + this.handler;
/*jshint evil: true */
eval(scriptSource);
}
};
var nextHandle = 1; // Spec says greater than zero
var tasksByHandle = {};
var currentlyRunningATask = false;
return {
addFromSetImmediateArguments: function (args) {
var handler = args[0];
var argsToHandle = Array.prototype.slice.call(args, 1);
var task = new Task(handler, argsToHandle);
var thisHandle = nextHandle++;
tasksByHandle[thisHandle] = task;
return thisHandle;
},
runIfPresent: function (handle) {
// From the spec: "Wait until any invocations of this algorithm started before this one have completed."
// So if we're currently running a task, we'll need to delay this invocation.
if (!currentlyRunningATask) {
var task = tasksByHandle[handle];
if (task) {
currentlyRunningATask = true;
try {
task.run();
} finally {
delete tasksByHandle[handle];
currentlyRunningATask = false;
}
}
} else {
// Delay by doing a setTimeout. setImmediate was tried instead, but in Firefox 7 it generated a
// "too much recursion" error.
global.setTimeout(function () {
tasks.runIfPresent(handle);
}, 0);
}
},
remove: function (handle) {
delete tasksByHandle[handle];
}
};
}());
function canUseNextTick() {
// Don't get fooled by e.g. browserify environments.
return typeof process === "object" &&
Object.prototype.toString.call(process) === "[object process]";
}
function canUseMessageChannel() {
return !!global.MessageChannel;
}
function canUsePostMessage() {
// The test against `importScripts` prevents this implementation from being installed inside a web worker,
// where `global.postMessage` means something completely different and can't be used for this purpose.
if (!global.postMessage || global.importScripts) {
return false;
}
var postMessageIsAsynchronous = true;
var oldOnMessage = global.onmessage;
global.onmessage = function () {
postMessageIsAsynchronous = false;
};
global.postMessage("", "*");
global.onmessage = oldOnMessage;
return postMessageIsAsynchronous;
}
function canUseReadyStateChange() {
return "document" in global && "onreadystatechange" in global.document.createElement("script");
}
function installNextTickImplementation(attachTo) {
attachTo.setImmediate = function () {
var handle = tasks.addFromSetImmediateArguments(arguments);
process.nextTick(function () {
tasks.runIfPresent(handle);
});
return handle;
};
}
function installMessageChannelImplementation(attachTo) {
var channel = new global.MessageChannel();
channel.port1.onmessage = function (event) {
var handle = event.data;
tasks.runIfPresent(handle);
};
attachTo.setImmediate = function () {
var handle = tasks.addFromSetImmediateArguments(arguments);
channel.port2.postMessage(handle);
return handle;
};
}
function installPostMessageImplementation(attachTo) {
// Installs an event handler on `global` for the `message` event: see
// * https://developer.mozilla.org/en/DOM/window.postMessage
// * http://www.whatwg.org/specs/web-apps/current-work/multipage/comms.html#crossDocumentMessages
var MESSAGE_PREFIX = "com.bn.NobleJS.setImmediate" + Math.random();
function isStringAndStartsWith(string, putativeStart) {
return typeof string === "string" && string.substring(0, putativeStart.length) === putativeStart;
}
function onGlobalMessage(event) {
// This will catch all incoming messages (even from other windows!), so we need to try reasonably hard to
// avoid letting anyone else trick us into firing off. We test the origin is still this window, and that a
// (randomly generated) unpredictable identifying prefix is present.
if (event.source === global && isStringAndStartsWith(event.data, MESSAGE_PREFIX)) {
var handle = event.data.substring(MESSAGE_PREFIX.length);
tasks.runIfPresent(handle);
}
}
if (global.addEventListener) {
global.addEventListener("message", onGlobalMessage, false);
} else {
global.attachEvent("onmessage", onGlobalMessage);
}
attachTo.setImmediate = function () {
var handle = tasks.addFromSetImmediateArguments(arguments);
// Make `global` post a message to itself with the handle and identifying prefix, thus asynchronously
// invoking our onGlobalMessage listener above.
global.postMessage(MESSAGE_PREFIX + handle, "*");
return handle;
};
}
function installReadyStateChangeImplementation(attachTo) {
attachTo.setImmediate = function () {
var handle = tasks.addFromSetImmediateArguments(arguments);
// Create a <script> element; its readystatechange event will be fired asynchronously once it is inserted
// into the document. Do so, thus queuing up the task. Remember to clean up once it's been called.
var scriptEl = global.document.createElement("script");
scriptEl.onreadystatechange = function () {
tasks.runIfPresent(handle);
scriptEl.onreadystatechange = null;
scriptEl.parentNode.removeChild(scriptEl);
scriptEl = null;
};
global.document.documentElement.appendChild(scriptEl);
return handle;
};
}
function installSetTimeoutImplementation(attachTo) {
attachTo.setImmediate = function () {
var handle = tasks.addFromSetImmediateArguments(arguments);
global.setTimeout(function () {
tasks.runIfPresent(handle);
}, 0);
return handle;
};
}
if (!global.setImmediate) {
// If supported, we should attach to the prototype of global, since that is where setTimeout et al. live.
var attachTo = typeof Object.getPrototypeOf === "function" && "setTimeout" in Object.getPrototypeOf(global) ?
Object.getPrototypeOf(global)
: global;
if (canUseNextTick()) {
// For Node.js before 0.9
installNextTickImplementation(attachTo);
} else if (canUsePostMessage()) {
// For non-IE10 modern browsers
installPostMessageImplementation(attachTo);
} else if (canUseMessageChannel()) {
// For web workers, where supported
installMessageChannelImplementation(attachTo);
} else if (canUseReadyStateChange()) {
// For IE 6–8
installReadyStateChangeImplementation(attachTo);
} else {
// For older browsers
installSetTimeoutImplementation(attachTo);
}
attachTo.clearImmediate = tasks.remove;
}
}(typeof global === "object" && global ? global : this));