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Kotlin Full Reflection Library

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/*
 * Copyright 2010-2015 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package kotlin.reflect.jvm.internal;

import kotlin.jvm.functions.Function0;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.lang.ref.SoftReference;

public class ReflectProperties {
    public static abstract class Val {
        private static final Object NULL_VALUE = new Object() {
        };

        @SuppressWarnings({"UnusedParameters", "unused"})
        public final T getValue(Object instance, Object metadata) {
            return invoke();
        }

        public abstract T invoke();

        protected Object escape(T value) {
            return value == null ? NULL_VALUE : value;
        }

        @SuppressWarnings("unchecked")
        protected T unescape(Object value) {
            return value == NULL_VALUE ? null : (T) value;
        }
    }

    // A delegate for a lazy property on a soft reference, whose initializer may be invoked multiple times
    // including simultaneously from different threads
    public static class LazySoftVal extends Val implements Function0 {
        private final Function0 initializer;
        private volatile SoftReference