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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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package com.oracle.truffle.js.nodes.control;

import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.js.nodes.JavaScriptNode;
import com.oracle.truffle.js.nodes.access.WriteNode;

public abstract class AbstractGeneratorBlockNode extends AbstractBlockNode {
    @Child protected JavaScriptNode readStateNode;
    @Child protected WriteNode writeStateNode;

    protected AbstractGeneratorBlockNode(JavaScriptNode[] statements, JavaScriptNode readStateNode, WriteNode writeStateNode) {
        super(statements);
        this.readStateNode = readStateNode;
        this.writeStateNode = writeStateNode;
    }

    protected final int getStateAndReset(VirtualFrame frame) {
        Object value = readStateNode.execute(frame);
        int index = (value instanceof Integer) ? (int) value : 0;
        setState(frame, 0);
        return index;
    }

    protected final void setState(VirtualFrame frame, int index) {
        writeStateNode.executeWrite(frame, index);
    }

    @Override
    public void executeVoid(VirtualFrame frame) {
        int index = getStateAndReset(frame);
        assert index < getStatements().length;
        block.executeVoid(frame, index);
    }

    @Override
    public Object execute(VirtualFrame frame) {
        int index = getStateAndReset(frame);
        assert index < getStatements().length;
        return block.executeGeneric(frame, index);
    }

    @Override
    public void executeVoid(VirtualFrame frame, JavaScriptNode node, int index, int startIndex) {
        if (index < startIndex) {
            return;
        }
        try {
            node.executeVoid(frame);
        } catch (YieldException e) {
            setState(frame, index);
            throw e;
        }
    }

    @Override
    public Object executeGeneric(VirtualFrame frame, JavaScriptNode node, int index, int startIndex) {
        assert index == getStatements().length - 1;
        try {
            return node.execute(frame);
        } catch (YieldException e) {
            setState(frame, index);
            throw e;
        }
    }
}