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 * person obtaining a copy of this software, associated documentation and/or
 * data (collectively the "Software"), free of charge and under any and all
 * copyright rights in the Software, and any and all patent rights owned or
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 * unmodified Software as contributed to or provided by such licensor, or (ii)
 * the Larger Works (as defined below), to deal in both
 *
 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
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package com.oracle.truffle.js.runtime;

import com.oracle.truffle.api.CompilerAsserts;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
import com.oracle.truffle.api.TruffleContext;
import com.oracle.truffle.api.frame.FrameDescriptor;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.source.SourceSection;
import com.oracle.truffle.js.lang.JavaScriptLanguage;
import com.oracle.truffle.js.runtime.builtins.JSFunction;

A RootNode for all cases where the body could throw and we would need to set the Realm to the
exception.
/**
 * A RootNode for all cases where the body could throw and we would need to set the Realm to the
 * exception.
 *
 */
public abstract class JavaScriptRealmBoundaryRootNode extends JavaScriptRootNode {

    @CompilationFinal private boolean seenException;
    @CompilationFinal private boolean seenNullRealm;

    protected JavaScriptRealmBoundaryRootNode(JavaScriptLanguage lang, SourceSection sourceSection, FrameDescriptor frameDescriptor) {
        super(lang, sourceSection, frameDescriptor);
    }

    @Override
    public final Object execute(VirtualFrame frame) {
        final JSContext context = getContext();
        CompilerAsserts.partialEvaluationConstant(context);

        final JSRealm currentRealm = getRealm();
        final JSRealm realm;
        final boolean enterContext;
        if (context.neverCreatedChildRealms()) {
            // fast path: if there are no child realms we are guaranteed to be in the right realm
            assert currentRealm == JSFunction.getRealm(JSFrameUtil.getFunctionObject(frame));
            realm = currentRealm;
            enterContext = false;
        } else {
            // must enter function context if realm != currentRealm
            realm = JSFunction.getRealm(JSFrameUtil.getFunctionObject(frame));
            enterContext = realm != currentRealm;
        }
        Object prev = null;
        TruffleContext childContext = null;

        if (enterContext) {
            childContext = realm.getTruffleContext();
            prev = childContext.enter(this);
        }
        try {
            return executeInRealm(frame);
        } catch (JSException ex) {
            if (!seenException) {
                CompilerDirectives.transferToInterpreterAndInvalidate();
                seenException = true;
            }
            if (ex.getRealm() == null) {
                if (!seenNullRealm) {
                    CompilerDirectives.transferToInterpreterAndInvalidate();
                    seenNullRealm = true;
                }
                ex.setRealm(realm);
            }
            throw ex;
        } catch (StackOverflowError ex) {
            CompilerDirectives.transferToInterpreter();
            throw Errors.createRangeErrorStackOverflow(this);
        } finally {
            if (enterContext) {
                childContext.leave(this, prev);
            }
        }
    }

    protected abstract Object executeInRealm(VirtualFrame frame);

    protected abstract JSContext getContext();

    protected JSRealm getRealm() {
        return getContext().getRealm();
    }
}