| /* |
| * Copyright 2000-2014 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. |
| */ |
| |
| /* |
| * Created by IntelliJ IDEA. |
| * User: cdr |
| * Date: Jul 26, 2007 |
| * Time: 3:52:05 PM |
| */ |
| package com.intellij.util.concurrency; |
| |
| import com.intellij.util.ReflectionUtil; |
| import org.jetbrains.annotations.NotNull; |
| import sun.misc.Unsafe; |
| |
| import java.lang.reflect.Field; |
| import java.lang.reflect.Modifier; |
| |
| /** |
| * Utility class similar to {@link java.util.concurrent.atomic.AtomicReferenceFieldUpdater} except: |
| * - removed access check in getAndSet() hot path for performance |
| * - new methods "forFieldXXX" added that search by field type instead of field name, which is useful in scrambled classes |
| */ |
| public class AtomicFieldUpdater<T,V> { |
| private static final Unsafe unsafe = getUnsafe(); |
| |
| @NotNull |
| public static Unsafe getUnsafe() { |
| Unsafe unsafe = ReflectionUtil.getField(Unsafe.class, null, Unsafe.class, "theUnsafe"); |
| if (unsafe == null) { |
| throw new RuntimeException("Could not find 'theUnsafe' field in the " + Unsafe.class); |
| } |
| return unsafe; |
| } |
| |
| private final long offset; |
| |
| @NotNull |
| public static <T, V> AtomicFieldUpdater<T, V> forFieldOfType(@NotNull Class<T> ownerClass, @NotNull Class<V> fieldType) { |
| return new AtomicFieldUpdater<T, V>(ownerClass, fieldType); |
| } |
| |
| @NotNull |
| public static <T> AtomicFieldUpdater<T, Long> forLongFieldIn(@NotNull Class<T> ownerClass) { |
| return new AtomicFieldUpdater<T, Long>(ownerClass, long.class); |
| } |
| |
| @NotNull |
| public static <T> AtomicFieldUpdater<T, Integer> forIntFieldIn(@NotNull Class<T> ownerClass) { |
| return new AtomicFieldUpdater<T, Integer>(ownerClass, int.class); |
| } |
| |
| private AtomicFieldUpdater(@NotNull Class<T> ownerClass, @NotNull Class<V> fieldType) { |
| Field found = getTheOnlyVolatileFieldOfClass(ownerClass, fieldType); |
| offset = unsafe.objectFieldOffset(found); |
| } |
| |
| @NotNull |
| private static <T,V> Field getTheOnlyVolatileFieldOfClass(@NotNull Class<T> ownerClass, @NotNull Class<V> fieldType) { |
| Field[] declaredFields = ownerClass.getDeclaredFields(); |
| Field found = null; |
| for (Field field : declaredFields) { |
| if ((field.getModifiers() & (Modifier.STATIC | Modifier.FINAL)) != 0) { |
| continue; |
| } |
| if (fieldType.isAssignableFrom(field.getType())) { |
| if (found == null) { |
| found = field; |
| } |
| else { |
| throw new IllegalArgumentException("Two fields of "+fieldType+" found in the "+ownerClass+": "+found.getName() + " and "+field.getName()); |
| } |
| } |
| } |
| if (found == null) { |
| throw new IllegalArgumentException("No (non-static, non-final) field of "+fieldType+" found in the "+ownerClass); |
| } |
| found.setAccessible(true); |
| if ((found.getModifiers() & Modifier.VOLATILE) == 0) { |
| throw new IllegalArgumentException("Field "+found+" in the "+ownerClass+" must be volatile"); |
| } |
| return found; |
| } |
| |
| public boolean compareAndSet(@NotNull T owner, V expected, V newValue) { |
| return unsafe.compareAndSwapObject(owner, offset, expected, newValue); |
| } |
| |
| public boolean compareAndSetLong(@NotNull T owner, long expected, long newValue) { |
| return unsafe.compareAndSwapLong(owner, offset, expected, newValue); |
| } |
| |
| public boolean compareAndSetInt(@NotNull T owner, int expected, int newValue) { |
| return unsafe.compareAndSwapInt(owner, offset, expected, newValue); |
| } |
| |
| public void set(@NotNull T owner, V newValue) { |
| unsafe.putObjectVolatile(owner, offset, newValue); |
| } |
| |
| public V get(@NotNull T owner) { |
| //noinspection unchecked |
| return (V)unsafe.getObjectVolatile(owner, offset); |
| } |
| } |