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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
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
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package com.oracle.truffle.js.nodes.binary;

import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.profiles.ConditionProfile;
import com.oracle.truffle.js.nodes.JavaScriptNode;
import com.oracle.truffle.js.nodes.cast.JSToBooleanNode;
import com.oracle.truffle.js.nodes.control.ResumableNode;
import com.oracle.truffle.js.nodes.control.YieldException;

public abstract class JSLogicalNode extends JSBinaryNode implements ResumableNode {

    private static final int RESUME_RIGHT = 1;
    private static final int RESUME_UNEXECUTED = 0;

    private final boolean negate;

    @Child private JSToBooleanNode toBooleanCast;

    protected final ConditionProfile canShortCircuit = ConditionProfile.createBinaryProfile();

    public JSLogicalNode(JavaScriptNode left, JavaScriptNode right, boolean negate) {
        super(left, right);
        this.negate = negate;
    }

    protected boolean toBoolean(Object operand) {
        if (toBooleanCast == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            toBooleanCast = insert(JSToBooleanNode.create());
        }
        boolean value = toBooleanCast.executeBoolean(operand);
        return negate ? !value : value;
    }

    protected boolean useLeftValue(Object leftValue) {
        return toBoolean(leftValue);
    }

    @Override
    public final Object execute(VirtualFrame frame) {
        Object leftValue = getLeft().execute(frame);
        if (canShortCircuit.profile(useLeftValue(leftValue))) {
            return leftValue;
        } else {
            return getRight().execute(frame);
        }
    }

    @Override
    public Object resume(VirtualFrame frame) {
        int state = getStateAsIntAndReset(frame);
        if (state == RESUME_UNEXECUTED) {
            Object leftValue = getLeft().execute(frame);
            if (canShortCircuit.profile(useLeftValue(leftValue))) {
                return leftValue;
            } else {
                try {
                    return getRight().execute(frame);
                } catch (YieldException e) {
                    setState(frame, RESUME_RIGHT);
                    throw e;
                }
            }
        } else {
            assert state == RESUME_RIGHT;
            try {
                return getRight().execute(frame);
            } catch (YieldException e) {
                setState(frame, RESUME_RIGHT);
                throw e;
            }
        }
    }
}