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1   /*
2   * Copyright 2017 The Netty Project
3   *
4   * The Netty Project licenses this file to you under the Apache License,
5   * version 2.0 (the "License"); you may not use this file except in compliance
6   * with the License. You may obtain a copy of the License at:
7   *
8   *   https://www.apache.org/licenses/LICENSE-2.0
9   *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13  * License for the specific language governing permissions and limitations
14  * under the License.
15  */
16  package io.netty.util.internal;
17  
18  import io.netty.util.internal.logging.InternalLogger;
19  import io.netty.util.internal.logging.InternalLoggerFactory;
20  
21  import java.lang.reflect.InvocationTargetException;
22  import java.lang.reflect.Method;
23  import java.nio.ByteBuffer;
24  import java.security.AccessController;
25  import java.security.PrivilegedAction;
26  
27  /**
28   * Provide a way to clean a ByteBuffer on Java9+.
29   */
30  final class CleanerJava9 implements Cleaner {
31      private static final InternalLogger logger = InternalLoggerFactory.getInstance(CleanerJava9.class);
32  
33      private static final Method INVOKE_CLEANER;
34  
35      static {
36          final Method method;
37          final Throwable error;
38          if (PlatformDependent0.hasUnsafe()) {
39              final ByteBuffer buffer = ByteBuffer.allocateDirect(1);
40              Object maybeInvokeMethod = AccessController.doPrivileged(new PrivilegedAction<Object>() {
41                  @Override
42                  public Object run() {
43                      try {
44                          // See https://bugs.openjdk.java.net/browse/JDK-8171377
45                          Method m = PlatformDependent0.UNSAFE.getClass().getDeclaredMethod(
46                                  "invokeCleaner", ByteBuffer.class);
47                          m.invoke(PlatformDependent0.UNSAFE, buffer);
48                          return m;
49                      } catch (NoSuchMethodException e) {
50                          return e;
51                      } catch (InvocationTargetException e) {
52                          return e;
53                      } catch (IllegalAccessException e) {
54                          return e;
55                      }
56                  }
57              });
58  
59              if (maybeInvokeMethod instanceof Throwable) {
60                  method = null;
61                  error = (Throwable) maybeInvokeMethod;
62              } else {
63                  method = (Method) maybeInvokeMethod;
64                  error = null;
65              }
66          } else {
67              method = null;
68              error = new UnsupportedOperationException("sun.misc.Unsafe unavailable");
69          }
70          if (error == null) {
71              logger.debug("java.nio.ByteBuffer.cleaner(): available");
72          } else {
73              logger.debug("java.nio.ByteBuffer.cleaner(): unavailable", error);
74          }
75          INVOKE_CLEANER = method;
76      }
77  
78      static boolean isSupported() {
79          return INVOKE_CLEANER != null;
80      }
81  
82      @Override
83      public void freeDirectBuffer(ByteBuffer buffer) {
84          // Try to minimize overhead when there is no SecurityManager present.
85          // See https://bugs.openjdk.java.net/browse/JDK-8191053.
86          if (System.getSecurityManager() == null) {
87              try {
88                  INVOKE_CLEANER.invoke(PlatformDependent0.UNSAFE, buffer);
89              } catch (Throwable cause) {
90                  PlatformDependent0.throwException(cause);
91              }
92          } else {
93              freeDirectBufferPrivileged(buffer);
94          }
95      }
96  
97      private static void freeDirectBufferPrivileged(final ByteBuffer buffer) {
98          Exception error = AccessController.doPrivileged(new PrivilegedAction<Exception>() {
99              @Override
100             public Exception run() {
101                 try {
102                     INVOKE_CLEANER.invoke(PlatformDependent0.UNSAFE, buffer);
103                 } catch (InvocationTargetException e) {
104                     return e;
105                 } catch (IllegalAccessException e) {
106                     return e;
107                 }
108                 return null;
109             }
110         });
111         if (error != null) {
112             PlatformDependent0.throwException(error);
113         }
114     }
115 }