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package com.oracle.truffle.js.runtime.objects;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import com.oracle.truffle.api.CompilerAsserts;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.object.Property;
import com.oracle.truffle.api.object.Shape;
import com.oracle.truffle.js.runtime.JSContext;
import com.oracle.truffle.js.runtime.JSRuntime;
import com.oracle.truffle.js.runtime.Symbol;
import com.oracle.truffle.js.runtime.util.DebugCounter;
import com.oracle.truffle.js.runtime.util.UnmodifiableArrayList;
import com.oracle.truffle.js.runtime.util.UnmodifiablePropertyKeyList;

Extra metadata associated with JavaScript object shapes.
See Also:
JSShape/**
 * Extra metadata associated with JavaScript object shapes.
 *
 * @see JSShape
 */
public final class JSShapeData {
    private static final Property[] EMPTY_PROPERTY_ARRAY = new Property[0];
    private static final String[] EMPTY_STRING_ARRAY = new String[0];
    private static final int UNKNOWN = -1;

    
The position in the property array where strings end and symbols start. /** The position in the property array where strings end and symbols start. */
    private int symbolsStartPos = UNKNOWN;
    
All properties, sorted using JSRuntime.comparePropertyKeys. /** All properties, sorted using {@link JSRuntime#comparePropertyKeys}. */
    private Property[] propertyArray;
    
Only enumerable properties with string keys (no symbols). /** Only enumerable properties with string keys (no symbols). */
    private String[] enumerablePropertyNames;

    private JSShapeData() {
    }

    private static Property[] createPropertiesArray(Shape shape) {
        CompilerAsserts.neverPartOfCompilation();
        propertyListAllocCount.inc();
        List<Property> ownProperties = shape.getPropertyList();
        sortProperties(ownProperties);
        return ownProperties.toArray(EMPTY_PROPERTY_ARRAY);
    }

    private static String[] createEnumerablePropertyNamesArray(Shape shape) {
        CompilerAsserts.neverPartOfCompilation();
        enumerablePropertyListAllocCount.inc();
        List<String> ownProperties = new ArrayList<>();
        shape.getPropertyList().forEach(property -> {
            if (JSProperty.isEnumerable(property) && property.getKey() instanceof String) {
                ownProperties.add((String) property.getKey());
            }
        });
        sortPropertyKeys(ownProperties);
        return ownProperties.toArray(EMPTY_STRING_ARRAY);
    }

    private static void sortProperties(List<Property> ownProperties) {
        CompilerAsserts.neverPartOfCompilation();
        Collections.sort(ownProperties, (o1, o2) -> JSRuntime.comparePropertyKeys(o1.getKey(), o2.getKey()));
    }

    private static void sortPropertyKeys(List<? extends Object> ownProperties) {
        CompilerAsserts.neverPartOfCompilation();
        Collections.sort(ownProperties, JSRuntime::comparePropertyKeys);
    }

    private static JSShapeData getShapeData(Shape shape) {
        CompilerAsserts.neverPartOfCompilation();
        JSContext context = JSShape.getJSContext(shape);
        synchronized (context) {
            Map<Shape, JSShapeData> map = context.getShapeDataMap();
            JSShapeData shapeData = map.get(shape);
            if (shapeData == null) {
                shapeData = new JSShapeData();
                map.put(shape, shapeData);
            }
            return shapeData;
        }
    }

    @TruffleBoundary
    private static Property[] getPropertiesArray(Shape shape) {
        assert shape.getPropertyCount() != 0;
        return getPropertiesArray(getShapeData(shape), shape);
    }

    private static Property[] getPropertiesArray(JSShapeData shapeData, Shape shape) {
        Property[] propertyArray = shapeData.propertyArray;
        if (propertyArray == null) {
            propertyArray = createPropertiesArray(shape);
            assert propertyArray.length == shape.getPropertyCount();
            shapeData.propertyArray = propertyArray;
        }
        return propertyArray;
    }

    private static int getSymbolsStart(JSShapeData shapeData, Property[] propertyArray) {
        int symbolsStart = shapeData.symbolsStartPos;
        if (symbolsStart == UNKNOWN) {
            shapeData.symbolsStartPos = symbolsStart = getSymbolsStart(propertyArray);
        }
        return symbolsStart;
    }

    private static int getSymbolsStart(Property[] propertyArray) {
        int pos = propertyArray.length;
        for (; pos > 0; pos--) {
            Property prev = propertyArray[pos - 1];
            if (!(prev.getKey() instanceof Symbol)) {
                break;
            }
        }
        return pos;
    }

    static UnmodifiableArrayList<Property> getProperties(Shape shape) {
        return asUnmodifiableList(shape.getPropertyCount() == 0 ? EMPTY_PROPERTY_ARRAY : getPropertiesArray(shape));
    }

    @TruffleBoundary
    private static String[] getEnumerablePropertyNamesArray(Shape shape) {
        assert shape.getPropertyCount() != 0;
        return getEnumerablePropertyNamesArray(getShapeData(shape), shape);
    }

    private static String[] getEnumerablePropertyNamesArray(JSShapeData shapeData, Shape shape) {
        String[] enumeratePropertyNames = shapeData.enumerablePropertyNames;
        if (enumeratePropertyNames == null) {
            enumeratePropertyNames = createEnumerablePropertyNamesArray(shape);
            shapeData.enumerablePropertyNames = enumeratePropertyNames;
        }
        return enumeratePropertyNames;
    }

    static UnmodifiableArrayList<String> getEnumerablePropertyNames(Shape shape) {
        return asUnmodifiableList(shape.getPropertyCount() == 0 ? EMPTY_STRING_ARRAY : getEnumerablePropertyNamesArray(shape));
    }

    @TruffleBoundary
    private static Property[] getPropertiesArrayIfHasEnumerablePropertyNames(Shape shape) {
        assert shape.getPropertyCount() != 0;
        JSShapeData shapeData = getShapeData(shape);
        if (getEnumerablePropertyNamesArray(shapeData, shape).length == 0) {
            return EMPTY_PROPERTY_ARRAY;
        } else {
            return getPropertiesArray(shapeData, shape);
        }
    }

    static UnmodifiableArrayList<Property> getPropertiesIfHasEnumerablePropertyNames(Shape shape) {
        return asUnmodifiableList(shape.getPropertyCount() == 0 ? EMPTY_PROPERTY_ARRAY : getPropertiesArrayIfHasEnumerablePropertyNames(shape));
    }

    static <T> UnmodifiablePropertyKeyList<T> getPropertyKeyList(Shape shape, boolean strings, boolean symbols) {
        CompilerAsserts.neverPartOfCompilation();
        Property[] propertyArray;
        int start;
        int end;
        if (shape.getPropertyCount() == 0) {
            propertyArray = EMPTY_PROPERTY_ARRAY;
            start = 0;
            end = 0;
        } else {
            JSShapeData shapeData = getShapeData(shape);
            propertyArray = getPropertiesArray(shapeData, shape);
            start = 0;
            end = propertyArray.length;
            if (!strings || !symbols) {
                int symbolsStart = getSymbolsStart(shapeData, propertyArray);
                if (!strings) {
                    start = symbolsStart;
                }
                if (!symbols) {
                    end = symbolsStart;
                }
            }
        }
        return UnmodifiablePropertyKeyList.create(propertyArray, start, end);
    }

    private static <T> UnmodifiableArrayList<T> asUnmodifiableList(T[] array) {
        return new UnmodifiableArrayList<>(array);
    }

    private static final DebugCounter enumerablePropertyListAllocCount = DebugCounter.create("Enumerable property lists allocated");
    private static final DebugCounter propertyListAllocCount = DebugCounter.create("Property lists allocated");
}