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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * The Universal Permissive License (UPL), Version 1.0
 *
 * Subject to the condition set forth below, permission is hereby granted to any
 * 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
 * freely licensable by each licensor hereunder covering either (i) the
 * 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
 *
 * (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
 * is contributed by such licensors),
 *
 * without restriction, including without limitation the rights to copy, create
 * derivative works of, display, perform, and distribute the Software and make,
 * use, sell, offer for sale, import, export, have made, and have sold the
 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
 *
 * This license is subject to the following condition:
 *
 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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package com.oracle.graal.python.lib;

import com.oracle.graal.python.builtins.objects.PNone;
import com.oracle.graal.python.builtins.objects.iterator.PBigRangeIterator;
import com.oracle.graal.python.builtins.objects.iterator.PIntRangeIterator;
import com.oracle.graal.python.nodes.ErrorMessages;
import com.oracle.graal.python.nodes.PNodeWithContext;
import com.oracle.graal.python.nodes.PRaiseNode;
import com.oracle.graal.python.nodes.call.special.CallUnaryMethodNode;
import com.oracle.graal.python.nodes.call.special.LookupSpecialMethodSlotNode;
import com.oracle.graal.python.nodes.object.GetClassNode;
import com.oracle.graal.python.nodes.object.IsBuiltinClassProfile;
import com.oracle.graal.python.runtime.exception.PException;
import com.oracle.graal.python.runtime.exception.PythonErrorType;
import com.oracle.graal.python.runtime.object.PythonObjectFactory;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.GenerateUncached;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.Frame;
import com.oracle.truffle.api.frame.VirtualFrame;

/**
 * Obtains the next value of an iterator. When the iterator is exhausted it returns {@code null}. It
 * never raises {@code StopIteration}.
 */
@GenerateUncached
public abstract class PyIterNextNode extends PNodeWithContext {
    public abstract Object execute(Frame frame, Object iterator);

    @Specialization
    Object doIntRange(PIntRangeIterator iterator) {
        if (iterator.hasNextInt()) {
            return iterator.nextInt();
        }
        iterator.setExhausted();
        return null;
    }

    @Specialization
    Object doBigIntRange(PBigRangeIterator iterator,
                    @Cached PythonObjectFactory factory) {
        if (iterator.hasNextBigInt()) {
            return factory.createInt(iterator.nextBigInt());
        }
        iterator.setExhausted();
        return null;
    }

    // TODO list, tuple, enumerate, dict keys, dict values, dict items, string, bytes

    @Specialization
    Object doGeneric(VirtualFrame frame, Object iterator,
                    @Cached GetClassNode getClassNode,
                    @Cached(parameters = "Next") LookupSpecialMethodSlotNode lookupNext,
                    @Cached CallUnaryMethodNode callNext,
                    @Cached IsBuiltinClassProfile stopIterationProfile,
                    @Cached PRaiseNode raiseNode) {
        Object nextMethod = lookupNext.execute(frame, getClassNode.execute(iterator), iterator);
        if (nextMethod == PNone.NO_VALUE) {
            throw raiseNode.raise(PythonErrorType.TypeError, ErrorMessages.OBJ_NOT_ITERABLE, iterator);
        }
        try {
            return callNext.executeObject(frame, nextMethod, iterator);
        } catch (PException e) {
            e.expectStopIteration(stopIterationProfile);
            return null;
        }
    }

    public static PyIterNextNode create() {
        return PyIterNextNodeGen.create();
    }

    public static PyIterNextNode getUncached() {
        return PyIterNextNodeGen.getUncached();
    }
}
