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

import com.oracle.truffle.api.dsl.Executed;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.instrumentation.Tag;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.js.nodes.JavaScriptNode;
import com.oracle.truffle.js.nodes.cast.JSToBooleanNode;
import com.oracle.truffle.js.nodes.function.JSFunctionCallNode;
import com.oracle.truffle.js.runtime.Errors;
import com.oracle.truffle.js.runtime.JSArguments;
import com.oracle.truffle.js.runtime.JSContext;
import com.oracle.truffle.js.runtime.JSRuntime;
import com.oracle.truffle.js.runtime.objects.IteratorRecord;

import java.util.Set;

Combines IteratorStep and IteratorValue in one node.
Equivalent to the following steps:

Let next be IteratorStep(iteratorRecord).
(opt) If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
ReturnIfAbrupt(next).
If next is false,

(opt) Set iteratorRecord.[[Done]] to true.
Return doneResult.

Else,

Let value be IteratorValue(next).
(opt) If value is an abrupt completion, set iteratorRecord.[[Done]] to true.
Return value.


/**
 * Combines IteratorStep and IteratorValue in one node.
 *
 * Equivalent to the following steps:
 *
 * <ol>
 * <li>Let next be IteratorStep(iteratorRecord).
 * <li>(opt) If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
 * <li>ReturnIfAbrupt(next).
 * <li>If next is false,
 * <ol>
 * <li>(opt) Set iteratorRecord.[[Done]] to true.
 * <li>Return doneResult.
 * </ol>
 * <li>Else,
 * <ol>
 * <li>Let value be IteratorValue(next).
 * <li>(opt) If value is an abrupt completion, set iteratorRecord.[[Done]] to true.
 * <li>Return value.
 * </ol>
 * </ol>
 */
public abstract class IteratorGetNextValueNode extends JavaScriptNode {
    @Child @Executed JavaScriptNode iteratorNode;
    @Child private PropertyGetNode getValueNode;
    @Child private PropertyGetNode getDoneNode;
    @Child private JSFunctionCallNode methodCallNode;
    @Child private IsJSObjectNode isObjectNode;
    @Child private JavaScriptNode doneResultNode;
    @Child private JSToBooleanNode toBooleanNode;
    private final boolean setDone;

    protected IteratorGetNextValueNode(JSContext context, JavaScriptNode iteratorNode, JavaScriptNode doneNode, boolean setDone) {
        this.iteratorNode = iteratorNode;
        this.getValueNode = PropertyGetNode.create(JSRuntime.VALUE, false, context);
        this.getDoneNode = PropertyGetNode.create(JSRuntime.DONE, false, context);
        this.methodCallNode = JSFunctionCallNode.createCall();
        this.isObjectNode = IsJSObjectNode.create();
        this.toBooleanNode = JSToBooleanNode.create();
        this.doneResultNode = doneNode;
        this.setDone = setDone;
    }

    public static IteratorGetNextValueNode create(JSContext context, JavaScriptNode iterator, JavaScriptNode doneNode, boolean setDone) {
        return IteratorGetNextValueNodeGen.create(context, iterator, doneNode, setDone);
    }

    private Object iteratorNext(IteratorRecord iteratorRecord) {
        Object next = iteratorRecord.getNextMethod();
        DynamicObject iterator = iteratorRecord.getIterator();
        Object result = methodCallNode.executeCall(JSArguments.createZeroArg(iterator, next));
        if (!isObjectNode.executeBoolean(result)) {
            throw Errors.createTypeErrorIterResultNotAnObject(result, this);
        }
        return result;
    }

    @Specialization
    protected Object iteratorStepAndGetValue(VirtualFrame frame, IteratorRecord iteratorRecord) {
        try {
            Object result = iteratorNext(iteratorRecord);
            boolean done = toBooleanNode.executeBoolean(getDoneNode.getValue(result));
            if (!done) {
                return getValueNode.getValue(result);
            } else {
                if (setDone) {
                    iteratorRecord.setDone(true);
                }
                return doneResultNode.execute(frame);
            }
        } catch (Exception ex) {
            if (setDone) {
                iteratorRecord.setDone(true);
            }
            throw ex;
        }
    }

    public abstract Object execute(VirtualFrame frame, IteratorRecord iteratorRecord);

    @Override
    protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) {
        return create(getValueNode.getContext(), cloneUninitialized(iteratorNode, materializedTags), cloneUninitialized(doneResultNode, materializedTags), setDone);
    }
}