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perf($q): move Deferred and Promise methods to prototypes
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NOTE: Deferred doesn't get all the advantages of moving methods to the prototype,
since the constructor binds instance methods to "this" to support unbounded execution.

Closes #8300
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@jeffbcross
jeffbcross committed Aug 4, 2014
1 parent 48b34dd commit 23bc92b
Showing 1 changed file with 128 additions and 121 deletions.
249 changes: 128 additions & 121 deletions src/ng/q.js
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Original file line number Diff line number Diff line change
Expand Up @@ -247,143 +247,122 @@ function qFactory(nextTick, exceptionHandler) {
* @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], callback[2]);
}
});
}
}
},


reject: function(reason) {
deferred.resolve(createInternalRejectedPromise(reason));
},
return new Deferred();
};

function Promise () {
this.$$pending = [];
}

notify: function(progress) {
if (pending) {
var callbacks = pending;
Promise.prototype = {
then: function(callback, errback, progressback) {
var result = new Deferred();

if (pending.length) {
nextTick(function() {
var callback;
for (var i = 0, ii = callbacks.length; i < ii; i++) {
callback = callbacks[i];
callback[2](progress);
}
});
}
var wrappedCallback = function(value) {
try {
result.resolve((isFunction(callback) ? callback : defaultCallback)(value));
} catch(e) {
result.reject(e);
exceptionHandler(e);
}
},


promise: {
then: function(callback, errback, progressback) {
var result = defer();

var wrappedCallback = function(value) {
try {
result.resolve((isFunction(callback) ? callback : defaultCallback)(value));
} catch(e) {
result.reject(e);
exceptionHandler(e);
}
};

var wrappedErrback = function(reason) {
try {
result.resolve((isFunction(errback) ? errback : defaultErrback)(reason));
} catch(e) {
result.reject(e);
exceptionHandler(e);
}
};

var wrappedProgressback = function(progress) {
try {
result.notify((isFunction(progressback) ? progressback : defaultCallback)(progress));
} catch(e) {
exceptionHandler(e);
}
};
};

var wrappedErrback = function(reason) {
try {
result.resolve((isFunction(errback) ? errback : defaultErrback)(reason));
} catch(e) {
result.reject(e);
exceptionHandler(e);
}
};

if (pending) {
pending.push([wrappedCallback, wrappedErrback, wrappedProgressback]);
} else {
value.then(wrappedCallback, wrappedErrback, wrappedProgressback);
}
var wrappedProgressback = function(progress) {
try {
result.notify((isFunction(progressback) ? progressback : defaultCallback)(progress));
} catch(e) {
exceptionHandler(e);
}
};

return result.promise;
},
if (this.$$pending) {
this.$$pending.push([wrappedCallback, wrappedErrback, wrappedProgressback]);
} else {
this.$$value.then(wrappedCallback, wrappedErrback, wrappedProgressback);
}

"catch": function(callback) {
return this.then(null, callback);
},
return result.promise;
},

"catch": function(callback) {
return this.then(null, callback);
},
"finally": function(callback) {
return this.then(function(value) {
return handleCallback(value, true, callback);
}, function(error) {
return handleCallback(error, false, callback);
});
}
};

"finally": function(callback) {
//Faster, more basic than angular.bind http://jsperf.com/angular-bind-vs-custom-vs-native
function simpleBind(context, fn) {
return function(value) {
fn.call(context, value);
};
}

function makePromise(value, resolved) {
var result = defer();
if (resolved) {
result.resolve(value);
} else {
result.reject(value);
}
return result.promise;
}
function Deferred () {
this.promise = new Promise();
//Necessary to support unbound execution :/
this.resolve = simpleBind(this, this.resolve);
this.reject = simpleBind(this, this.reject);
this.notify = simpleBind(this, this.notify);
}

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@kuroky360

kuroky360 Jan 16, 2016

Contributor

@jeffbcross I got a bit confusing for the code [as below]

 this.resolve =simpleBind(this,this.resolve);
 ...

to support unbounded execution -> means what? Can you help me to understand the code?
Thanks.

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@lgalfaso

lgalfaso Jan 16, 2016

Contributor

@kuroky360
Check https://github.com/angular/angular.js/blob/master/test/ng/qSpec.js#L899

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@kuroky360

kuroky360 Jan 17, 2016

Contributor

Thanks for the quick feedback.
Got it.

function handleCallback(value, isResolved) {
var callbackOutput = null;
try {
callbackOutput = (callback ||defaultCallback)();
} catch(e) {
return makePromise(e, false);
Deferred.prototype = {
resolve: function(val) {
if (this.promise.$$pending) {
var callbacks = this.promise.$$pending;
this.promise.$$pending = undefined;
this.promise.$$value = ref(val);

if (callbacks.length) {
nextTick(simpleBind(this, function() {
var callback;
for (var i = 0, ii = callbacks.length; i < ii; i++) {
callback = callbacks[i];
this.promise.$$value.then(callback[0], callback[1], callback[2]);
}
if (isPromiseLike(callbackOutput)) {
return callbackOutput.then(function() {
return makePromise(value, isResolved);
}, function(error) {
return makePromise(error, false);
});
} else {
return makePromise(value, isResolved);
}));
}
}
},
reject: function(reason) {
this.resolve(createInternalRejectedPromise(reason));
},
notify: function(progress) {
if (this.promise.$$pending) {
var callbacks = this.promise.$$pending;

if (this.promise.$$pending.length) {
nextTick(function() {
var callback;
for (var i = 0, ii = callbacks.length; i < ii; i++) {
callback = callbacks[i];
callback[2](progress);
}
}

return this.then(function(value) {
return handleCallback(value, true);
}, function(error) {
return handleCallback(error, false);
});
}
}
};

return deferred;
}
};


var ref = function(value) {
if (isPromiseLike(value)) return value;
return {
then: function(callback) {
var result = defer();
var result = new Deferred();
nextTick(function() {
result.resolve(callback(value));
});
Expand Down Expand Up @@ -430,15 +409,43 @@ function qFactory(nextTick, exceptionHandler) {
* @returns {Promise} Returns a promise that was already resolved as rejected with the `reason`.
*/
var reject = function(reason) {
var result = defer();
var result = new Deferred();
result.reject(reason);
return result.promise;
};

var makePromise = function makePromise(value, resolved) {
var result = new Deferred();
if (resolved) {
result.resolve(value);
} else {
result.reject(value);
}
return result.promise;
};

var handleCallback = function handleCallback(value, isResolved, callback) {
var callbackOutput = null;
try {
callbackOutput = (callback ||defaultCallback)();
} catch(e) {
return makePromise(e, false);
}
if (isPromiseLike(callbackOutput)) {
return callbackOutput.then(function() {
return makePromise(value, isResolved);
}, function(error) {
return makePromise(error, false);
});
} else {
return makePromise(value, isResolved);
}
};

var createInternalRejectedPromise = function(reason) {
return {
then: function(callback, errback) {
var result = defer();
var result = new Deferred();
nextTick(function() {
try {
result.resolve((isFunction(errback) ? errback : defaultErrback)(reason));
Expand Down Expand Up @@ -467,7 +474,7 @@ function qFactory(nextTick, exceptionHandler) {
* @returns {Promise} Returns a promise of the passed value or promise
*/
var when = function(value, callback, errback, progressback) {
var result = defer(),
var result = new Deferred(),
done;

var wrappedCallback = function(value) {
Expand Down Expand Up @@ -541,7 +548,7 @@ function qFactory(nextTick, exceptionHandler) {
* with the same rejection value.
*/
function all(promises) {
var deferred = defer(),
var deferred = new Deferred(),
counter = 0,
results = isArray(promises) ? [] : {};

Expand Down Expand Up @@ -575,7 +582,7 @@ function qFactory(nextTick, exceptionHandler) {
return new Q(resolver);
}

var deferred = defer();
var deferred = new Deferred();

function resolveFn(value) {
deferred.resolve(value);
Expand Down

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