PromiseConstructor.js   [plain text]

/*
 * Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

function all(iterable)
{
    "use strict";

    if (!@isObject(this))
        throw new TypeError("|this| is not a object");

    // FIXME: Fix this code when @@species well-known symbol is landed.
    // https://bugs.webkit.org/show_bug.cgi?id=146624
    var constructor = this;

    var promiseCapability = @newPromiseCapability(constructor);

    var values = [];
    var index = 0;
    var remainingElementsCount = 1;

    function newResolveElement(index)
    {
        var alreadyCalled = false;
        return function (argument)
        {
            if (alreadyCalled)
                return undefined;
            alreadyCalled = true;

            @putByValDirect(values, index, argument);

            --remainingElementsCount;
            if (remainingElementsCount === 0)
                return promiseCapability.@resolve.@call(undefined, values);

            return undefined;
        }
    }

    try {
        for (var value of iterable) {
            @putByValDirect(values, index, undefined);
            var nextPromise = constructor.resolve(value);
            var resolveElement = newResolveElement(index);
            ++remainingElementsCount;
            nextPromise.then(resolveElement, promiseCapability.@reject);
            ++index;
        }

        --remainingElementsCount;
        if (remainingElementsCount === 0)
            promiseCapability.@resolve.@call(undefined, values);
    } catch (error) {
        promiseCapability.@reject.@call(undefined, error);
    }

    return promiseCapability.@promise;
}

function race(iterable)
{
    "use strict";

    if (!@isObject(this))
        throw new TypeError("|this| is not a object");

    // FIXME: Fix this code when @@species well-known symbol is landed.
    // https://bugs.webkit.org/show_bug.cgi?id=146624
    var constructor = this;

    var promiseCapability = @newPromiseCapability(constructor);

    try {
        for (var value of iterable) {
            var nextPromise = constructor.resolve(value);
            nextPromise.then(promiseCapability.@resolve, promiseCapability.@reject);
        }
    } catch (error) {
        promiseCapability.@reject.@call(undefined, error);
    }

    return promiseCapability.@promise;
}

function reject(reason)
{
    "use strict";

    if (!@isObject(this))
        throw new TypeError("|this| is not a object");

    var promiseCapability = @newPromiseCapability(this);

    promiseCapability.@reject.@call(undefined, reason);

    return promiseCapability.@promise;
}

function resolve(value)
{
    "use strict";

    if (!@isObject(this))
        throw new TypeError("|this| is not a object");

    if (@isPromise(value)) {
        var valueConstructor = value.constructor;
        if (valueConstructor === this)
            return value;
    }

    var promiseCapability = @newPromiseCapability(this);

    promiseCapability.@resolve.@call(undefined, value);

    return promiseCapability.@promise;
}