Plato - dojo/_base/Deferred.js

define([
	"./kernel",
	"../Deferred",
	"../promise/Promise",
	"../errors/CancelError",
	"../has",
	"./lang",
	"../when"
], function(dojo, NewDeferred, Promise, CancelError, has, lang, when){
	// module:
	//		dojo/_base/Deferred

var result, finished, canceled, fired, isError, head, nextListener;
		var promise = (this.promise = new Promise());

this.isResolved = promise.isResolved = function(){
			// summary:
			//		Checks whether the deferred has been resolved.
			// returns: Boolean

return fired == 0;
		};

this.isRejected = promise.isRejected = function(){
			// summary:
			//		Checks whether the deferred has been rejected.
			// returns: Boolean

return fired == 1;
		};

this.isFulfilled = promise.isFulfilled = function(){
			// summary:
			//		Checks whether the deferred has been resolved or rejected.
			// returns: Boolean

return fired >= 0;
		};

this.isCanceled = promise.isCanceled = function(){
			// summary:
			//		Checks whether the deferred has been canceled.
			// returns: Boolean

return canceled;
		};

// calling resolve will resolve the promise
		this.resolve = this.callback = function(value){
			// summary:
			//		Fulfills the Deferred instance successfully with the provide value
			this.fired = fired = 0;
			this.results = [value, null];
			complete(value);
		};

// calling error will indicate that the promise failed
		this.reject = this.errback = function(error){
			// summary:
			//		Fulfills the Deferred instance as an error with the provided error
			isError = true;
			this.fired = fired = 1;
			if(has("config-useDeferredInstrumentation")){
				if(NewDeferred.instrumentRejected){
					NewDeferred.instrumentRejected(error, !!nextListener);
				}
			}
			complete(error);
			this.results = [null, error];
		};
		// call progress to provide updates on the progress on the completion of the promise
		this.progress = function(update){
			// summary:
			//		Send progress events to all listeners
			var listener = nextListener;
			while(listener){
				var progress = listener.progress;
				progress && progress(update);
				listener = listener.next;
			}
		};
		this.addCallbacks = function(callback, errback){
			// summary:
			//		Adds callback and error callback for this deferred instance.
			// callback: Function?
			//		The callback attached to this deferred object.
			// errback: Function?
			//		The error callback attached to this deferred object.
			// returns:
			//		Returns this deferred object.
			this.then(callback, errback, mutator);
			return this;	// Deferred
		};
		// provide the implementation of the promise
		promise.then = this.then = function(/*Function?*/resolvedCallback, /*Function?*/errorCallback, /*Function?*/progressCallback){
			// summary:
			//		Adds a fulfilledHandler, errorHandler, and progressHandler to be called for
			//		completion of a promise. The fulfilledHandler is called when the promise
			//		is fulfilled. The errorHandler is called when a promise fails. The
			//		progressHandler is called for progress events. All arguments are optional
			//		and non-function values are ignored. The progressHandler is not only an
			//		optional argument, but progress events are purely optional. Promise
			//		providers are not required to ever create progress events.
			//
			//		This function will return a new promise that is fulfilled when the given
			//		fulfilledHandler or errorHandler callback is finished. This allows promise
			//		operations to be chained together. The value returned from the callback
			//		handler is the fulfillment value for the returned promise. If the callback
			//		throws an error, the returned promise will be moved to failed state.
			//
			// returns:
			//		Returns a new promise that represents the result of the
			//		execution of the callback. The callbacks will never affect the original promises value.
			// example:
			//		An example of using a CommonJS compliant promise:
			//		|	asyncComputeTheAnswerToEverything().
			//		|		then(addTwo).
			//		|		then(printResult, onError);
			//		|	>44
			//
			var returnDeferred = progressCallback == mutator ? this : new Deferred(promise.cancel);
			var listener = {
				resolved: resolvedCallback,
				error: errorCallback,
				progress: progressCallback,
				deferred: returnDeferred
			};
			if(nextListener){
				head = head.next = listener;
			}
			else{
				nextListener = head = listener;
			}
			if(finished){
				notify();
			}
			return returnDeferred.promise; // Promise
		};
		var deferred = this;
		promise.cancel = this.cancel = function(){
			// summary:
			//		Cancels the asynchronous operation
			if(!finished){
				var error = canceller && canceller(deferred);
				if(!finished){
					if (!(error instanceof Error)){
						error = new CancelError(error);
					}
					error.log = false;
					deferred.reject(error);
				}
			}
			canceled = true;
		};
		freeze(promise);
	};
	lang.extend(Deferred, {
		addCallback: function(/*Function*/ callback){
			// summary:
			//		Adds successful callback for this deferred instance.
			// returns:
			//		Returns this deferred object.
			return this.addCallbacks(lang.hitch.apply(dojo, arguments));	// Deferred
		},

addErrback: function(/*Function*/ errback){
			// summary:
			//		Adds error callback for this deferred instance.
			// returns:
			//		Returns this deferred object.
			return this.addCallbacks(null, lang.hitch.apply(dojo, arguments));	// Deferred
		},

addBoth: function(/*Function*/ callback){
			// summary:
			//		Add handler as both successful callback and error callback for this deferred instance.
			// returns:
			//		Returns this deferred object.
			var enclosed = lang.hitch.apply(dojo, arguments);
			return this.addCallbacks(enclosed, enclosed);	// Deferred
		},
		fired: -1
	});

Deferred.when = dojo.when = when;

return Deferred;
});

dojo/_base/Deferred.js

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