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

import com.oracle.truffle.api.Assumption;
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.nodes.InvalidAssumptionException;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.api.object.FinalLocationException;
import com.oracle.truffle.api.object.IncompatibleLocationException;
import com.oracle.truffle.api.object.Location;
import com.oracle.truffle.api.object.Property;
import com.oracle.truffle.api.object.Shape;
import com.oracle.truffle.api.utilities.AlwaysValidAssumption;
import com.oracle.truffle.api.utilities.NeverValidAssumption;

public abstract class SLWritePropertyCacheNode extends Node {
    protected static final int CACHE_LIMIT = 3;

    protected final String propertyName;

    public SLWritePropertyCacheNode(String propertyName) {
        this.propertyName = propertyName;
    }

    public abstract void executeObject(DynamicObject receiver, Object value);

    @Specialization(guards = {"location != null", "shape.check(receiver)", "location.canSet(receiver, value)"}, assumptions = {"shape.getValidAssumption()"}, limit = "CACHE_LIMIT")
    public void writeExistingPropertyCached(DynamicObject receiver, Object value, //
                    @Cached("lookupLocation(receiver, value)") Location location, //
                    @Cached("receiver.getShape()") Shape shape, //
                    @Cached("ensureValid(receiver)") Assumption validAssumption) {
        try {
            validAssumption.check();
        } catch (InvalidAssumptionException e) {
            executeObject(receiver, value);
            return;
        }
        try {
            location.set(receiver, value, shape);
        } catch (IncompatibleLocationException | FinalLocationException e) {
            throw new IllegalStateException(e);
        }
    }

    @Specialization(guards = {"existing == null", "shapeBefore.check(receiver)", "shapeAfter != null", "newLocation.canSet(receiver, value)"}, assumptions = {"shapeBefore.getValidAssumption()",
                    "shapeAfter.getValidAssumption()"}, limit = "CACHE_LIMIT")
    public void writeNewPropertyCached(DynamicObject receiver, Object value, //
                    @Cached("lookupLocation(receiver, value)") @SuppressWarnings("unused") Location existing, //
                    @Cached("receiver.getShape()") Shape shapeBefore, //
                    @Cached("defineProperty(receiver, value)") Shape shapeAfter, //
                    @Cached("getLocation(shapeAfter)") Location newLocation, //
                    @Cached("ensureValid(receiver)") Assumption validAssumption) {
        try {
            validAssumption.check();
        } catch (InvalidAssumptionException e) {
            executeObject(receiver, value);
            return;
        }
        try {
            newLocation.set(receiver, value, shapeBefore, shapeAfter);
        } catch (IncompatibleLocationException e) {
            throw new IllegalStateException(e);
        }
    }

    @Specialization(contains = {"writeExistingPropertyCached", "writeNewPropertyCached"})
    @TruffleBoundary
    public void writeUncached(DynamicObject receiver, Object value) {
        receiver.define(propertyName, value);
    }

    protected final Location lookupLocation(DynamicObject object, Object value) {
        final Shape oldShape = object.getShape();
        final Property property = oldShape.getProperty(propertyName);

        if (property != null && property.getLocation().canSet(object, value)) {
            return property.getLocation();
        } else {
            return null;
        }
    }

    protected final Shape defineProperty(DynamicObject receiver, Object value) {
        Shape oldShape = receiver.getShape();
        Shape newShape = oldShape.defineProperty(propertyName, value, 0);
        return newShape;
    }

    protected final Location getLocation(Shape newShape) {
        return newShape.getProperty(propertyName).getLocation();
    }

    protected static Assumption ensureValid(DynamicObject receiver) {
        return receiver.updateShape() ? NeverValidAssumption.INSTANCE : AlwaysValidAssumption.INSTANCE;
    }
}