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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
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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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 *
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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.array;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.api.profiles.ConditionProfile;
import com.oracle.truffle.api.profiles.ValueProfile;
import com.oracle.truffle.js.nodes.access.JSHasPropertyNode;
import com.oracle.truffle.js.runtime.JSContext;
import com.oracle.truffle.js.runtime.JSRuntime;
import com.oracle.truffle.js.runtime.array.ScriptArray;
import com.oracle.truffle.js.runtime.objects.JSObject;
import com.oracle.truffle.js.runtime.objects.Null;

Provides the functionality of ScriptArray.firstElementIndex but additionally adheres to the
prototype chain. It is implemented in a specialized and profiled fashion.
/**
 * Provides the functionality of ScriptArray.firstElementIndex but additionally adheres to the
 * prototype chain. It is implemented in a specialized and profiled fashion.
 *
 */
public abstract class JSArrayFirstElementIndexNode extends JSArrayElementIndexNode {

    protected JSArrayFirstElementIndexNode(JSContext context) {
        super(context);
    }

    public static JSArrayFirstElementIndexNode create(JSContext context) {
        return JSArrayFirstElementIndexNodeGen.create(context);
    }

    public final long executeLong(Object object, long length) {
        return executeLong(object, length, isArray(object));
    }

    public abstract long executeLong(Object object, long length, boolean isArray);

    @Specialization(guards = {"isArray", "!hasPrototypeElements(object)", "getArrayType(object) == cachedArrayType",
                    "!cachedArrayType.hasHoles(object)"}, limit = "MAX_CACHED_ARRAY_TYPES")
    public long doWithoutHolesCached(DynamicObject object, @SuppressWarnings("unused") long length, @SuppressWarnings("unused") boolean isArray,
                    @Cached("getArrayTypeIfArray(object, isArray)") ScriptArray cachedArrayType) {
        assert isSupportedArray(object) && cachedArrayType == getArrayType(object);
        return cachedArrayType.firstElementIndex(object);
    }

    @Specialization(guards = {"isArray", "!hasPrototypeElements(object)", "!hasHoles(object)"}, replaces = "doWithoutHolesCached")
    public long doWithoutHolesUncached(DynamicObject object, @SuppressWarnings("unused") long length, @SuppressWarnings("unused") boolean isArray) {
        assert isSupportedArray(object);
        return getArrayType(object).firstElementIndex(object);
    }

    @Specialization(guards = {"isArray", "!hasPrototypeElements(object)", "getArrayType(object) == cachedArrayType",
                    "cachedArrayType.hasHoles(object)"}, limit = "MAX_CACHED_ARRAY_TYPES")
    public long doWithHolesCached(DynamicObject object, long length, @SuppressWarnings("unused") boolean isArray,
                    @Cached("getArrayTypeIfArray(object, isArray)") ScriptArray cachedArrayType,
                    @Cached("create(context)") JSArrayNextElementIndexNode nextElementIndexNode,
                    @Cached("createBinaryProfile()") ConditionProfile isZero) {
        assert isSupportedArray(object) && cachedArrayType == getArrayType(object);
        return holesArrayImpl(object, length, cachedArrayType, nextElementIndexNode, isZero);
    }

    @Specialization(guards = {"isArray", "hasPrototypeElements(object) || hasHoles(object)"}, replaces = "doWithHolesCached")
    public long doWithHolesUncached(DynamicObject object, long length, @SuppressWarnings("unused") boolean isArray,
                    @Cached("create(context)") JSArrayNextElementIndexNode nextElementIndexNode,
                    @Cached("createBinaryProfile()") ConditionProfile isZero,
                    @Cached("createClassProfile()") ValueProfile arrayTypeProfile) {
        assert isSupportedArray(object);
        ScriptArray array = arrayTypeProfile.profile(getArrayType(object));
        return holesArrayImpl(object, length, array, nextElementIndexNode, isZero);
    }

    private long holesArrayImpl(DynamicObject object, long length, ScriptArray array,
                    JSArrayNextElementIndexNode nextElementIndexNode, ConditionProfile isZero) {
        long firstIndex = array.firstElementIndex(object);
        if (isZero.profile(firstIndex == 0)) {
            return firstIndex;
        }

        // object itself might have larger indices in the shape
        DynamicObject prototype = object;
        while (prototype != Null.instance) {
            long firstProtoIndex = nextElementIndexNode.executeLong(prototype, -1, length);
            if (firstProtoIndex == 0) {
                return 0;
            }
            if (firstIndex > 0) {
                firstIndex = Math.min(firstIndex, firstProtoIndex);
            }
            if (!context.getArrayPrototypeNoElementsAssumption().isValid()) {
                prototype = JSObject.getPrototype(prototype);
            } else {
                break;
            }
        }
        return firstIndex;
    }

    @Specialization(guards = {"!isArray", "isSuitableForEnumBasedProcessingUsingOwnKeys(object, length)"})
    public long firstObjectViaEnumeration(DynamicObject object, long length, @SuppressWarnings("unused") boolean isArray,
                    @Cached("create()") JSHasPropertyNode hasPropertyNode) {
        if (hasPropertyNode.executeBoolean(object, 0)) {
            return 0;
        }
        return firstObjectViaEnumerationIntl(object, length);
    }

    @Specialization(guards = {"!isArray", "!isSuitableForEnumBasedProcessingUsingOwnKeys(object, length)", "isSuitableForEnumBasedProcessing(object, length)"})
    public long firstObjectViaFullEnumeration(DynamicObject object, long length, @SuppressWarnings("unused") boolean isArray,
                    @Cached("create()") JSHasPropertyNode hasPropertyNode) {
        if (hasPropertyNode.executeBoolean(object, 0)) {
            return 0;
        }
        return firstObjectViaFullEnumerationIntl(object, length);
    }

    @Specialization(guards = {"!isArray", "!isSuitableForEnumBasedProcessing(object, length)"})
    public long doObject(Object object, long length, @SuppressWarnings("unused") boolean isArray,
                    @Cached("create()") JSHasPropertyNode hasPropertyNode) {
        long index = 0;
        while (!hasPropertyNode.executeBoolean(object, index) && index <= (length - 1)) {
            index++;
        }
        return index;
    }

    @TruffleBoundary
    private static long firstObjectViaEnumerationIntl(DynamicObject object, long length) {
        long result = length == 0 ? 1 : length; // not found
        for (Object key : JSObject.ownPropertyKeys(object)) {
            if (key == null) {
                continue;
            }
            if (key instanceof String) {
                long candidate = JSRuntime.propertyNameToIntegerIndex((String) key);
                // no other length check necessary - current result is guarded by ToLength
                if (candidate >= 0 && candidate < result) {
                    result = candidate;
                }
            }
        }
        return result;
    }

    @TruffleBoundary
    private static long firstObjectViaFullEnumerationIntl(DynamicObject object, long length) {
        long result = Long.MAX_VALUE;
        DynamicObject chainObject = object;
        do {
            result = Math.min(result, firstObjectViaEnumerationIntl(chainObject, length));
            chainObject = JSObject.getPrototype(chainObject);
        } while (chainObject != Null.instance);
        return result;
    }

}