Source/JavaScriptCore/builtins/ShadowRealmPrototype.js

/*
 * Copyright (C) 2021 Igalia S.L.
 *
 * 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. AND ITS CONTRIBUTORS ``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 ITS CONTRIBUTORS
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// Wrap a value at the boundary between the incubating realm and `shadowRealm`:
// if `fromShadowRealm` is false, we are wrapping an object from the incubating
// realm; if true, we are wrapping an object from the shadow realm
@globalPrivate
function wrap(fromShadowRealm, shadowRealm, target)
{
    "use strict";

    if (@isCallable(target)) {
        var wrapped = function(/* args... */) {
            var length = arguments.length;
            var wrappedArgs = @newArrayWithSize(length);
            for (var index = 0; index < length; ++index)
                // Note that for arguments, we flip `fromShadowRealm` since to
                // wrap a function from realm A to work in realm B, we need to
                // wrap the arguments (from realm B) to work in realm A before
                // calling the wrapped function
                @putByValDirect(wrappedArgs, index, @wrap(!fromShadowRealm, shadowRealm, arguments[index]));

            var result = target.@apply(@undefined, wrappedArgs);
            return @wrap(fromShadowRealm, shadowRealm, result);
        };
        delete wrapped['name'];
        delete wrapped['length'];

        // Because this function (wrap) will run with the incubating realm
        // active, we only need to fix the prototype on `wrapped` if we are
        // moving the function from the incubating realm to the shadow realm
        if (!fromShadowRealm)
            @moveFunctionToRealm(wrapped, shadowRealm);
        return wrapped;
    } else if (@isObject(target)) {
        @throwTypeError("value passing between realms must be callable or primitive");
    }
    return target;
}

function evaluate(sourceText)
{
    "use strict";

    if (!@isShadowRealm(this))
        @throwTypeError("`%ShadowRealm%.evaluate requires that |this| be a ShadowRealm instance");

    if (typeof sourceText !== 'string')
        @throwTypeError("`%ShadowRealm%.evaluate requires that the |sourceText| argument be a string");

    var result = @evalInRealm(this, sourceText)
    return @wrap(true, this, result);
}

function importValue(specifier, exportName)
{
    "use strict";

    if (!@isShadowRealm(this))
        @throwTypeError("`%ShadowRealm%.importValue requires that |this| be a ShadowRealm instance");

    var exportNameString = @toString(exportName);
    var specifierString = @toString(specifier);

    var lookupBinding = (module) => {
        var lookup = module[exportNameString]
        if (lookup === @undefined)
            @throwTypeError("%ShadowRealm%.importValue requires |exportName| to exist in the |specifier|");

        return @wrap(true, this, lookup);
    };

    var crossRealmThrow = (error) => {
        // re-throw because import issues raise errors using the realm's global object
        @throwTypeError(@toString(error));
    };

    return @importInRealm(this, specifierString).@then(lookupBinding, crossRealmThrow);
}