Source/JavaScriptCore/builtins/InternalPromiseConstructor.js

/*
 * Copyright (C) 2015 Apple Inc. All rights reserved.
 *
 * 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
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 */

function internalAll(array)
{
    // This function is intended to be used in the JSC internals.
    // The implementation should take care not to perform the user
    // observable / trappable operations.
    //
    // 1. Don't use for-of and iterables. This function only accepts
    //    the dense array of the promises.
    // 2. Don't look up this.constructor / @@species. Always construct
    //    the plain Promise object.

    "use strict";

    var promiseCapability = @newPromiseCapability(@InternalPromise);

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

    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 {
        if (array.length === 0)
            promiseCapability.@resolve.@call(@undefined, values);
        else {
            for (var index = 0, length = array.length; index < length; ++index) {
                var value = array[index];
                @putByValDirect(values, index, @undefined);

                var nextPromiseCapability = @newPromiseCapability(@InternalPromise);
                nextPromiseCapability.@resolve.@call(@undefined, value);
                var nextPromise = nextPromiseCapability.@promise;

                var resolveElement = newResolveElement(index);
                ++remainingElementsCount;
                nextPromise.then(resolveElement, promiseCapability.@reject);
            }
        }
    } catch (error) {
        promiseCapability.@reject.@call(@undefined, error);
    }

    return promiseCapability.@promise;
}