rpuch commented on a change in pull request #567: URL: https://github.com/apache/ignite-3/pull/567#discussion_r788685299
########## File path: modules/network/src/main/java/org/apache/ignite/internal/network/serialization/marshal/ProxyMarshaller.java ########## @@ -0,0 +1,122 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 org.apache.ignite.internal.network.serialization.marshal; + +import java.io.DataInputStream; +import java.io.DataOutputStream; +import java.io.IOException; +import java.lang.reflect.Field; +import java.lang.reflect.InvocationHandler; +import java.lang.reflect.Method; +import java.lang.reflect.Proxy; + +/** + * (Un)marshalling logic specific to {@link Proxy} instances. + */ +class ProxyMarshaller { + private final ValueWriter<Object> valueWriter; + private final ValueReader<Object> valueReader; + + /** + * The placeholder to use when pre-instantiating a Proxy (because we didn't read the actual handler yet). + */ + private static final InvocationHandler placeholderInvocationHandler = new PlaceholderInvocationHandler(); + + private static final Field proxyHandlerField = findProxyHandlerField(); + + private static Field findProxyHandlerField() { + Field field; + try { + field = Proxy.class.getDeclaredField("h"); + } catch (NoSuchFieldException e) { + throw new ExceptionInInitializerError(e); + } + + field.setAccessible(true); + + return field; + } + + ProxyMarshaller(ValueWriter<Object> valueWriter, ValueReader<Object> valueReader) { + this.valueWriter = valueWriter; + this.valueReader = valueReader; + } + + boolean isProxyClass(Class<?> classToCheck) { + return Proxy.isProxyClass(classToCheck); + } + + void writeProxy(Object proxy, DataOutputStream output, MarshallingContext context) throws MarshalException, IOException { + assert Proxy.isProxyClass(proxy.getClass()); + + BuiltInMarshalling.writeClassArray(proxy.getClass().getInterfaces(), output, context); + + valueWriter.write(Proxy.getInvocationHandler(proxy), output, context); + } + + Object preInstantiateProxy(DataInputStream input, UnmarshallingContext context) throws UnmarshalException, IOException { + Class<?>[] interfaces = BuiltInMarshalling.readClassArray(input, context); + + return Proxy.newProxyInstance(context.classLoader(), interfaces, placeholderInvocationHandler); + } + + void fillProxyFrom(DataInputStream input, Object proxyToFill, UnmarshallingContext context) throws UnmarshalException, IOException { + InvocationHandler invocationHandler = readInvocationHandler(input, context); + replaceInvocationHandler(proxyToFill, invocationHandler); + } + + private InvocationHandler readInvocationHandler(DataInputStream input, UnmarshallingContext context) + throws IOException, UnmarshalException { + Object object = valueReader.read(input, context); + if (!(object instanceof InvocationHandler)) { + throw new UnmarshalException("Expected an InvocationHandler, but read " + object); + } + return (InvocationHandler) object; + } + + private void replaceInvocationHandler(Object objectToFill, InvocationHandler invocationHandler) throws UnmarshalException { + try { + proxyHandlerField.set(objectToFill, invocationHandler); + } catch (IllegalAccessException e) { + throw new UnmarshalException("Cannot set Proxy.h", e); + } + } + + private static class PlaceholderInvocationHandler implements InvocationHandler { + /** {@inheritDoc} */ + @Override + public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { + if ("equals".equals(method.getName()) && method.getParameterTypes().length == 1 + && method.getParameterTypes()[0] == Object.class) { + return proxy == args[0]; + } + if ("hashCode".equals(method.getName()) && noArgs(method)) { + return hashCode(); + } + if ("toString".equals(method.getName()) && noArgs(method)) { + return "Proxy with placeholder"; + } + + throw new UnsupportedOperationException("This is a dummy placeholder, but it was got an invocation on " + method); Review comment: If we just return `null`, it may cause another exception in another place that will mask the original problem. On the other hand, if we throw an exception ourselves (as we know that we should not reach that point of execution), this makes the problem clear to a person who encounters it. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
