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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
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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
 * 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
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package com.oracle.graal.python.lib;

import com.oracle.graal.python.builtins.objects.common.HashingStorage;
import com.oracle.graal.python.builtins.objects.common.HashingStorageLibrary;
import com.oracle.graal.python.builtins.objects.common.HashingStorageLibrary.ForEachNode;
import com.oracle.graal.python.builtins.objects.dict.PDict;
import com.oracle.graal.python.runtime.object.PythonObjectFactory;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.dsl.Bind;
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.library.CachedLibrary;
import com.oracle.truffle.api.nodes.Node;

/**
 * Equivalent to use for PyDict_Keys, which returns a list of the dictionary keys. The CPython
 * function does a hard cast to the internal dict structure or aborts with BadInternalCall.
 */
@GenerateUncached
public abstract class PyDictKeys extends Node {
    public abstract Object execute(PDict dict);

    @CompilerDirectives.ValueType
    protected static final class EachKeyState {
        private final Object[] ary;
        private int idx;

        EachKeyState(Object[] ary) {
            this.ary = ary;
            this.idx = 0;
        }
    }

    @GenerateUncached
    abstract static class ForEachKey extends ForEachNode<EachKeyState> {

        public abstract EachKeyState executeReprState(Object key, EachKeyState arg);

        @Override
        public final EachKeyState execute(Object key, EachKeyState arg) {
            return executeReprState(key, arg);
        }

        @Specialization
        static EachKeyState append(Object key, EachKeyState current) {
            current.ary[current.idx++] = key;
            return current;
        }
    }

    @Specialization(limit = "3")
    @SuppressWarnings("unused")
    static final Object getString(PDict dict,
                    @Bind("dict.getDictStorage()") HashingStorage dictStorage,
                    @Cached ForEachKey consumerNode,
                    @Cached PythonObjectFactory factory,
                    @CachedLibrary("dictStorage") HashingStorageLibrary lib) {
        int len = lib.length(dictStorage);
        EachKeyState result = lib.forEach(dictStorage, consumerNode, new EachKeyState(new Object[len]));
        return factory.createList(result.ary);
    }
}
