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修复StampedCache的get方法非原子问题

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Looly 2023-12-09 01:10:23 +08:00
parent dfc0b4ecf1
commit 6f4a115032
7 changed files with 168 additions and 115 deletions
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10
hutool-core/src/main/java/org/dromara/hutool/core/cache/impl/AbstractCache.java vendored
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@ -262,16 +262,10 @@ public abstract class AbstractCache<K, V> implements Cache<K, V> {
* 移除key对应的对象，不加锁
*
* @param key 键
* @param withMissCount 是否计数丢失数
* @return 移除的对象，无返回null
*/
protected CacheObj<K, V> removeWithoutLock(final K key, final boolean withMissCount) {
final CacheObj<K, V> co = cacheMap.remove(MutableObj.of(key));
if (withMissCount) {
// 在丢失计数有效的情况下，移除一般为get时的超时操作，此处应该丢失数+1
this.missCount.increment();
}
return co;
protected CacheObj<K, V> removeWithoutLock(final K key) {
return cacheMap.remove(MutableObj.of(key));
}
/**

2
hutool-core/src/main/java/org/dromara/hutool/core/cache/impl/FIFOCache.java vendored
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@ -83,7 +83,7 @@ public class FIFOCache<K, V> extends StampedCache<K, V> {
// 清理结束后依旧是满的，则删除第一个被缓存的对象
if (isFull() && null != first) {
removeWithoutLock(first.key, false);
removeWithoutLock(first.key);
onRemove(first.key, first.obj);
count++;
}

85
hutool-core/src/main/java/org/dromara/hutool/core/cache/impl/ReentrantCache.java vendored
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@ -30,7 +30,6 @@ public abstract class ReentrantCache<K, V> extends AbstractCache<K, V> {
private static final long serialVersionUID = 1L;
// 一些特殊缓存，例如使用了LinkedHashMap的缓存，由于get方法也会改变Map的结构，导致无法使用读写锁
// TODO 最优的解决方案是使用Guava的ConcurrentLinkedHashMap，此处使用简化的互斥锁
protected final ReentrantLock lock = new ReentrantLock();
@Override
@ -45,49 +44,12 @@ public abstract class ReentrantCache<K, V> extends AbstractCache<K, V> {
@Override
public boolean containsKey(final K key) {
lock.lock();
try {
// 不存在或已移除
final CacheObj<K, V> co = getWithoutLock(key);
if (co == null) {
return false;
}
if (!co.isExpired()) {
// 命中
return true;
}
} finally {
lock.unlock();
}
// 过期
remove(key, true);
return false;
return null != getOrRemoveExpired(key, false, false);
}
@Override
public V get(final K key, final boolean isUpdateLastAccess) {
CacheObj<K, V> co;
lock.lock();
try {
co = getWithoutLock(key);
} finally {
lock.unlock();
}
// 未命中
if (null == co) {
missCount.increment();
return null;
} else if (!co.isExpired()) {
hitCount.increment();
return co.get(isUpdateLastAccess);
}
// 过期，既不算命中也不算非命中
remove(key, true);
return null;
return getOrRemoveExpired(key, isUpdateLastAccess, true);
}
@Override
@ -114,7 +76,16 @@ public abstract class ReentrantCache<K, V> extends AbstractCache<K, V> {
@Override
public void remove(final K key) {
remove(key, false);
CacheObj<K, V> co;
lock.lock();
try {
co = removeWithoutLock(key);
} finally {
lock.unlock();
}
if (null != co) {
onRemove(co.key, co.obj);
}
}
@Override
@ -138,21 +109,37 @@ public abstract class ReentrantCache<K, V> extends AbstractCache<K, V> {
}
/**
* 移除key对应的对象
*
* @param key 键
* @param withMissCount 是否计数丢失数
* 获得值或清除过期值
* @param key 键
* @param isUpdateLastAccess 是否更新最后访问时间
* @param isUpdateCount 是否更新计数器
* @return 值或null
*/
private void remove(final K key, final boolean withMissCount) {
private V getOrRemoveExpired(final K key, final boolean isUpdateLastAccess, final boolean isUpdateCount) {
CacheObj<K, V> co;
lock.lock();
try {
co = removeWithoutLock(key, withMissCount);
co = getWithoutLock(key);
if(null != co && co.isExpired()){
//过期移除
removeWithoutLock(key);
co = null;
}
} finally {
lock.unlock();
}
if (null != co) {
onRemove(co.key, co.obj);
// 未命中
if (null == co) {
if(isUpdateCount){
missCount.increment();
}
return null;
}
if(isUpdateCount){
hitCount.increment();
}
return co.get(isUpdateLastAccess);
}
}

122
hutool-core/src/main/java/org/dromara/hutool/core/cache/impl/StampedCache.java vendored
View File

@ -45,54 +45,12 @@ public abstract class StampedCache<K, V> extends AbstractCache<K, V>{
@Override
public boolean containsKey(final K key) {
final long stamp = lock.readLock();
try {
// 不存在或已移除
final CacheObj<K, V> co = getWithoutLock(key);
if (co == null) {
return false;
}
if (!co.isExpired()) {
// 命中
return true;
}
} finally {
lock.unlockRead(stamp);
}
// 过期
remove(key, true);
return false;
return null != get(key, false, false);
}
@Override
public V get(final K key, final boolean isUpdateLastAccess) {
// 尝试读取缓存，使用乐观读锁
long stamp = lock.tryOptimisticRead();
CacheObj<K, V> co = getWithoutLock(key);
if(!lock.validate(stamp)){
// 有写线程修改了此对象，悲观读
stamp = lock.readLock();
try {
co = getWithoutLock(key);
} finally {
lock.unlockRead(stamp);
}
}
// 未命中
if (null == co) {
missCount.increment();
return null;
} else if (!co.isExpired()) {
hitCount.increment();
return co.get(isUpdateLastAccess);
}
// 过期，既不算命中也不算非命中
remove(key, true);
return null;
return get(key, isUpdateLastAccess, true);
}
@Override
@ -119,7 +77,16 @@ public abstract class StampedCache<K, V> extends AbstractCache<K, V>{
@Override
public void remove(final K key) {
remove(key, false);
final long stamp = lock.writeLock();
CacheObj<K, V> co;
try {
co = removeWithoutLock(key);
} finally {
lock.unlockWrite(stamp);
}
if (null != co) {
onRemove(co.key, co.obj);
}
}
@Override
@ -133,21 +100,78 @@ public abstract class StampedCache<K, V> extends AbstractCache<K, V>{
}
/**
* 移除key对应的对象
* 获取值
*
* @param key 键
* @param isUpdateLastAccess 是否更新最后修改时间
* @param isUpdateCount 是否更新命中数，get时更新，contains时不更新
* @return 值或null
*/
private V get(final K key, final boolean isUpdateLastAccess, final boolean isUpdateCount) {
// 尝试读取缓存，使用乐观读锁
long stamp = lock.tryOptimisticRead();
CacheObj<K, V> co = getWithoutLock(key);
if (false == lock.validate(stamp)) {
// 有写线程修改了此对象，悲观读
stamp = lock.readLock();
try {
co = getWithoutLock(key);
} finally {
lock.unlockRead(stamp);
}
}
// 未命中
if (null == co) {
if (isUpdateCount) {
missCount.increment();
}
return null;
} else if (false == co.isExpired()) {
if (isUpdateCount) {
hitCount.increment();
}
return co.get(isUpdateLastAccess);
}
// 悲观锁，二次检查
return getOrRemoveExpired(key, isUpdateCount);
}
/**
* 同步获取值，如果过期则移除之
*
* @param key 键
* @param withMissCount 是否计数丢失数
* @param isUpdateCount 是否更新命中数，get时更新，contains时不更新
* @return 有效值或null
*/
private void remove(final K key, final boolean withMissCount) {
private V getOrRemoveExpired(final K key, final boolean isUpdateCount) {
final long stamp = lock.writeLock();
CacheObj<K, V> co;
try {
co = removeWithoutLock(key, withMissCount);
co = getWithoutLock(key);
if (null == co) {
return null;
}
if (false == co.isExpired()) {
// 首先尝试获取值，如果值存在且有效，返回之
if (isUpdateCount) {
hitCount.increment();
}
return co.getValue();
}
// 无效移除
co = removeWithoutLock(key);
if(isUpdateCount){
missCount.increment();
}
} finally {
lock.unlockWrite(stamp);
}
if (null != co) {
onRemove(co.key, co.obj);
}
return null;
}
}

48
hutool-core/src/test/java/org/dromara/hutool/core/cache/IssueI8MEIXTest.java vendored Normal file
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@ -0,0 +1,48 @@
/*
* Copyright (c) 2023. looly(loolly@aliyun.com)
* Hutool is licensed under Mulan PSL v2.
* You can use this software according to the terms and conditions of the Mulan PSL v2.
* You may obtain a copy of Mulan PSL v2 at:
* https://license.coscl.org.cn/MulanPSL2
* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
* See the Mulan PSL v2 for more details.
*/
package org.dromara.hutool.core.cache;
import org.dromara.hutool.core.cache.impl.TimedCache;
import org.dromara.hutool.core.lang.Console;
import org.dromara.hutool.core.thread.ThreadUtil;
import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;
/**
* https://gitee.com/dromara/hutool/issues/I8MEIX<br>
* get操作非原子
*/
public class IssueI8MEIXTest {
@Test
@Disabled
void getRemoveTest() {
final TimedCache<String, String> cache = new TimedCache<>(200);
cache.put("a", "123");
ThreadUtil.sleep(300);
// 测试时，在get后的remove前加sleep测试在读取过程中put新值的问题
ThreadUtil.execute(() -> {
Console.log("get begin.");
Console.log(cache.get("a"));
});
ThreadUtil.execute(() -> {
ThreadUtil.sleep(200);
cache.put("a", "456");
Console.log("put ok.");
});
ThreadUtil.sleep(1000);
}
}

2
hutool-core/src/test/java/org/dromara/hutool/core/text/dfa/IssueI5Q4HDTest.java
View File

@ -32,6 +32,6 @@ public class IssueI5Q4HDTest {
wordTree.addWords(keyWordSet);
//DateUtil.beginOfHour()
final List<String> strings = wordTree.matchAll(content, -1, true, true);
Assertions.assertEquals("[站房, 站房建设, 面积较小, 不符合规范要求, 辅助设施, 站房]", strings.toString());
Assertions.assertEquals("[站房建设, 面积较小, 不符合规范要求, 辅助设施, 站房]", strings.toString());
}
}

14
hutool-core/src/test/java/org/dromara/hutool/core/text/dfa/NFATest.java
View File

@ -53,7 +53,7 @@ public class NFATest {
stopWatch.start("wordtree_char_find");
final List<String> ans2 = wordTree.matchAll(input, -1, true, true);
stopWatch.stop();
Assertions.assertEquals("she,he,her,say", String.join(",", ans2));
Assertions.assertEquals("she,her,say", String.join(",", ans2));
//Console.log(stopWatch.prettyPrint());
}
@ -120,7 +120,7 @@ public class NFATest {
wordTreeLocal.addWords("say", "her", "he", "she", "shr");
final List<String> ans2 = wordTreeLocal.matchAll(input, -1, true, true);
stopWatch.stop();
Assertions.assertEquals("she,he,her,say", String.join(",", ans2));
Assertions.assertEquals("she,her,say", String.join(",", ans2));
//Console.log(stopWatch.prettyPrint());
}
@ -157,8 +157,8 @@ public class NFATest {
final List<String> result1 = wordTreeLocal.matchAll(input, -1, true, true);
stopWatch.stop();
Assertions.assertEquals(3, result1.size());
Assertions.assertEquals("赵,赵啊,赵啊三", String.join(",", result1));
Assertions.assertEquals(1, result1.size());
Assertions.assertEquals("赵啊三", String.join(",", result1));
//Console.log(stopWatch.prettyPrint());
}
@ -196,8 +196,8 @@ public class NFATest {
.collect(Collectors.toList());
stopWatch.stop();
Assertions.assertEquals(3, result1.size());
Assertions.assertEquals("赵,赵啊,赵啊三", String.join(",", result1));
Assertions.assertEquals(1, result1.size());
Assertions.assertEquals("赵啊三", String.join(",", result1));
//Console.log(stopWatch.prettyPrint());
}
@ -233,7 +233,7 @@ public class NFATest {
stopWatch.stop();
Assertions.assertEquals(1, result1.size());
Assertions.assertEquals("赵", String.join(",", result1));
Assertions.assertEquals("赵啊三", String.join(",", result1));
//Console.log(stopWatch.prettyPrint());
}