blob: afef22edca0880f2292113ca00c6d0276efb9ba7 [file] [log] [blame]
import {
objectOrFunction,
isFunction
} from './utils';
import asap from './asap';
function noop() {}
var PENDING = void 0;
var FULFILLED = 1;
var REJECTED = 2;
var GET_THEN_ERROR = new ErrorObject();
function selfFullfillment() {
return new TypeError("You cannot resolve a promise with itself");
}
function cannotReturnOwn() {
return new TypeError('A promises callback cannot return that same promise.')
}
function getThen(promise) {
try {
return promise.then;
} catch(error) {
GET_THEN_ERROR.error = error;
return GET_THEN_ERROR;
}
}
function tryThen(then, value, fulfillmentHandler, rejectionHandler) {
try {
then.call(value, fulfillmentHandler, rejectionHandler);
} catch(e) {
return e;
}
}
function handleForeignThenable(promise, thenable, then) {
asap(function(promise) {
var sealed = false;
var error = tryThen(then, thenable, function(value) {
if (sealed) { return; }
sealed = true;
if (thenable !== value) {
resolve(promise, value);
} else {
fulfill(promise, value);
}
}, function(reason) {
if (sealed) { return; }
sealed = true;
reject(promise, reason);
}, 'Settle: ' + (promise._label || ' unknown promise'));
if (!sealed && error) {
sealed = true;
reject(promise, error);
}
}, promise);
}
function handleOwnThenable(promise, thenable) {
if (thenable._state === FULFILLED) {
fulfill(promise, thenable._result);
} else if (promise._state === REJECTED) {
reject(promise, thenable._result);
} else {
subscribe(thenable, undefined, function(value) {
resolve(promise, value);
}, function(reason) {
reject(promise, reason);
});
}
}
function handleMaybeThenable(promise, maybeThenable) {
if (maybeThenable.constructor === promise.constructor) {
handleOwnThenable(promise, maybeThenable);
} else {
var then = getThen(maybeThenable);
if (then === GET_THEN_ERROR) {
reject(promise, GET_THEN_ERROR.error);
} else if (then === undefined) {
fulfill(promise, maybeThenable);
} else if (isFunction(then)) {
handleForeignThenable(promise, maybeThenable, then);
} else {
fulfill(promise, maybeThenable);
}
}
}
function resolve(promise, value) {
if (promise === value) {
reject(promise, selfFullfillment());
} else if (objectOrFunction(value)) {
handleMaybeThenable(promise, value);
} else {
fulfill(promise, value);
}
}
function publishRejection(promise) {
if (promise._onerror) {
promise._onerror(promise._result);
}
publish(promise);
}
function fulfill(promise, value) {
if (promise._state !== PENDING) { return; }
promise._result = value;
promise._state = FULFILLED;
if (promise._subscribers.length === 0) {
} else {
asap(publish, promise);
}
}
function reject(promise, reason) {
if (promise._state !== PENDING) { return; }
promise._state = REJECTED;
promise._result = reason;
asap(publishRejection, promise);
}
function subscribe(parent, child, onFulfillment, onRejection) {
var subscribers = parent._subscribers;
var length = subscribers.length;
parent._onerror = null;
subscribers[length] = child;
subscribers[length + FULFILLED] = onFulfillment;
subscribers[length + REJECTED] = onRejection;
if (length === 0 && parent._state) {
asap(publish, parent);
}
}
function publish(promise) {
var subscribers = promise._subscribers;
var settled = promise._state;
if (subscribers.length === 0) { return; }
var child, callback, detail = promise._result;
for (var i = 0; i < subscribers.length; i += 3) {
child = subscribers[i];
callback = subscribers[i + settled];
if (child) {
invokeCallback(settled, child, callback, detail);
} else {
callback(detail);
}
}
promise._subscribers.length = 0;
}
function ErrorObject() {
this.error = null;
}
var TRY_CATCH_ERROR = new ErrorObject();
function tryCatch(callback, detail) {
try {
return callback(detail);
} catch(e) {
TRY_CATCH_ERROR.error = e;
return TRY_CATCH_ERROR;
}
}
function invokeCallback(settled, promise, callback, detail) {
var hasCallback = isFunction(callback),
value, error, succeeded, failed;
if (hasCallback) {
value = tryCatch(callback, detail);
if (value === TRY_CATCH_ERROR) {
failed = true;
error = value.error;
value = null;
} else {
succeeded = true;
}
if (promise === value) {
reject(promise, cannotReturnOwn());
return;
}
} else {
value = detail;
succeeded = true;
}
if (promise._state !== PENDING) {
// noop
} else if (hasCallback && succeeded) {
resolve(promise, value);
} else if (failed) {
reject(promise, error);
} else if (settled === FULFILLED) {
fulfill(promise, value);
} else if (settled === REJECTED) {
reject(promise, value);
}
}
function initializePromise(promise, resolver) {
try {
resolver(function resolvePromise(value){
resolve(promise, value);
}, function rejectPromise(reason) {
reject(promise, reason);
});
} catch(e) {
reject(promise, e);
}
}
export {
noop,
resolve,
reject,
fulfill,
subscribe,
publish,
publishRejection,
initializePromise,
invokeCallback,
FULFILLED,
REJECTED,
PENDING
};