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| 1 | +/* |
| 2 | + * Licensed to the Apache Software Foundation (ASF) under one |
| 3 | + * or more contributor license agreements. See the NOTICE file |
| 4 | + * distributed with this work for additional information |
| 5 | + * regarding copyright ownership. The ASF licenses this file |
| 6 | + * to you under the Apache License, Version 2.0 (the |
| 7 | + * "License"); you may not use this file except in compliance |
| 8 | + * with the License. You may obtain a copy of the License at |
| 9 | + * |
| 10 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | + * |
| 12 | + * Unless required by applicable law or agreed to in writing, software |
| 13 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 14 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | + * See the License for the specific language governing permissions and |
| 16 | + * limitations under the License. |
| 17 | + */ |
| 18 | + |
| 19 | +package org.apache.hadoop.util; |
| 20 | + |
| 21 | +import org.apache.hadoop.classification.InterfaceAudience; |
| 22 | + |
| 23 | +import org.apache.hadoop.util.dynamic.BindingUtils; |
| 24 | +import org.apache.hadoop.util.dynamic.DynConstructors; |
| 25 | +import org.apache.hadoop.util.dynamic.DynMethods; |
| 26 | + |
| 27 | +import java.lang.reflect.InvocationHandler; |
| 28 | +import java.lang.reflect.Proxy; |
| 29 | + |
| 30 | +@InterfaceAudience.Private |
| 31 | +public class SignalUtil { |
| 32 | + |
| 33 | + static final Class<?> jdkSignalClazz = |
| 34 | + BindingUtils.loadClassSafely("sun.misc.Signal"); |
| 35 | + static final Class<?> jdkSignalHandlerClazz = |
| 36 | + BindingUtils.loadClassSafely("sun.misc.SignalHandler"); |
| 37 | + |
| 38 | + static DynConstructors.Ctor<?> jdkSignalCtor = |
| 39 | + new DynConstructors.Builder() |
| 40 | + .impl(jdkSignalClazz, String.class) |
| 41 | + .build(); |
| 42 | + |
| 43 | + static DynMethods.StaticMethod jdkSignalHandleStaticMethod = |
| 44 | + new DynMethods.Builder("handle") |
| 45 | + .impl(jdkSignalClazz, jdkSignalClazz, jdkSignalHandlerClazz) |
| 46 | + .buildStatic(); |
| 47 | + |
| 48 | + static DynMethods.StaticMethod jdkSignalRaiseStaticMethod = |
| 49 | + new DynMethods.Builder("raise") |
| 50 | + .impl(jdkSignalClazz, jdkSignalClazz) |
| 51 | + .buildStatic(); |
| 52 | + |
| 53 | + static DynMethods.UnboundMethod jdkSignalHandlerHandleMethod = |
| 54 | + new DynMethods.Builder("handle") |
| 55 | + .impl(jdkSignalHandlerClazz, jdkSignalClazz) |
| 56 | + .build(); |
| 57 | + |
| 58 | + @InterfaceAudience.Private |
| 59 | + public static class Signal { |
| 60 | + private final static DynMethods.UnboundMethod getNumberMethod = |
| 61 | + new DynMethods.Builder("getNumber").impl(jdkSignalClazz).build(); |
| 62 | + |
| 63 | + private final static DynMethods.UnboundMethod getNameMethod = |
| 64 | + new DynMethods.Builder("getName").impl(jdkSignalClazz).build(); |
| 65 | + |
| 66 | + private final Object delegate; |
| 67 | + |
| 68 | + public Signal(String name) { |
| 69 | + this.delegate = jdkSignalCtor.newInstance(name); |
| 70 | + } |
| 71 | + |
| 72 | + public Signal(Object delegate) { |
| 73 | + Preconditions.checkArgument(jdkSignalClazz.isInstance(delegate), |
| 74 | + String.format("Expected class is '%s', but actual class is '%s'", |
| 75 | + jdkSignalClazz.getName(), delegate.getClass().getName())); |
| 76 | + this.delegate = delegate; |
| 77 | + } |
| 78 | + |
| 79 | + public int getNumber() { |
| 80 | + return getNumberMethod.bind(delegate).invoke(); |
| 81 | + } |
| 82 | + |
| 83 | + public String getName() { |
| 84 | + return getNameMethod.bind(delegate).invoke(); |
| 85 | + } |
| 86 | + |
| 87 | + public boolean equals(Object obj) { |
| 88 | + if (this == obj) { |
| 89 | + return true; |
| 90 | + } |
| 91 | + if (obj instanceof Signal) { |
| 92 | + return delegate.equals(((Signal)obj).delegate); |
| 93 | + } |
| 94 | + return false; |
| 95 | + } |
| 96 | + |
| 97 | + public int hashCode() { |
| 98 | + return delegate.hashCode(); |
| 99 | + } |
| 100 | + |
| 101 | + public String toString() { |
| 102 | + return delegate.toString(); |
| 103 | + } |
| 104 | + } |
| 105 | + |
| 106 | + @InterfaceAudience.Private |
| 107 | + public interface Handler { |
| 108 | + void handle(Signal sig); |
| 109 | + } |
| 110 | + |
| 111 | + static class JdkSignalHandlerImpl implements Handler { |
| 112 | + |
| 113 | + private final Object delegate; |
| 114 | + |
| 115 | + JdkSignalHandlerImpl(Handler handler) { |
| 116 | + this.delegate = Proxy.newProxyInstance( |
| 117 | + getClass().getClassLoader(), |
| 118 | + new Class<?>[] { jdkSignalHandlerClazz }, |
| 119 | + (proxyObj, method, args) -> { |
| 120 | + if ("handle".equals(method.getName()) && args.length == 1 && jdkSignalClazz.isInstance(args[0])) { |
| 121 | + handler.handle(new Signal(args[0])); |
| 122 | + return null; |
| 123 | + } else { |
| 124 | + return InvocationHandler.invokeDefault(proxyObj, method, args); |
| 125 | + } |
| 126 | + } |
| 127 | + ); |
| 128 | + } |
| 129 | + |
| 130 | + JdkSignalHandlerImpl(Object delegate) { |
| 131 | + Preconditions.checkArgument(jdkSignalHandlerClazz.isInstance(delegate), |
| 132 | + String.format("Expected class is '%s', but actual class is '%s'", |
| 133 | + jdkSignalHandlerClazz.getName(), delegate.getClass().getName())); |
| 134 | + this.delegate = delegate; |
| 135 | + } |
| 136 | + |
| 137 | + @Override |
| 138 | + public void handle(Signal sig) { |
| 139 | + jdkSignalHandlerHandleMethod.bind(delegate).invoke(sig.delegate); |
| 140 | + } |
| 141 | + } |
| 142 | + |
| 143 | + public static Handler handle(Signal sig, Handler handler) { |
| 144 | + Object preHandle = jdkSignalHandleStaticMethod.invoke( |
| 145 | + sig.delegate, new JdkSignalHandlerImpl(handler).delegate); |
| 146 | + return new JdkSignalHandlerImpl(preHandle); |
| 147 | + } |
| 148 | + |
| 149 | + public static void raise(Signal sig) throws IllegalArgumentException { |
| 150 | + jdkSignalRaiseStaticMethod.invoke(sig.delegate); |
| 151 | + } |
| 152 | +} |
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