com.oracle.svm.thirdparty.gson.GsonFeature Maven / Gradle / Ivy
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/*
* Copyright (c) 2017, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.oracle.svm.thirdparty.gson;
import java.util.Optional;
import org.graalvm.nativeimage.hosted.Feature;
import org.graalvm.nativeimage.hosted.RuntimeReflection;
import com.oracle.svm.util.ReflectionUtil;
/**
* Support for the Gson library on SubstrateVM.
*
* Gson uses reflection to instantiate data classes and write properties. All such data classes need
* to be registered manually by the user using the {@link RuntimeReflection runtime reflection
* support} of Substrate VM. It is not feasible to automatically detect all necessary classes.
*
* This feature registers parts of {@code sun.misc.Unsafe} as reflectively accessible. Gson uses it
* internally to instantiate classes that do not have a no-argument constructor.
*/
public final class GsonFeature implements Feature {
private static Optional requiredModule() {
return ModuleLayer.boot().findModule("jdk.unsupported");
}
@Override
public boolean isInConfiguration(IsInConfigurationAccess access) {
/* `sun.misc.Unsafe` is in `jdk.unsupported` */
return requiredModule().isPresent();
}
@Override
public void beforeAnalysis(BeforeAnalysisAccess access) {
Class gsonClass = access.findClassByName("com.google.gson.Gson");
if (gsonClass != null) {
access.registerReachabilityHandler(GsonFeature::makeUnsafeReflectivelyAccessible, gsonClass);
}
}
private static void makeUnsafeReflectivelyAccessible(DuringAnalysisAccess a) {
Class unsafeClass = a.findClassByName("sun.misc.Unsafe");
RuntimeReflection.register(unsafeClass);
RuntimeReflection.register(ReflectionUtil.lookupField(unsafeClass, "theUnsafe"));
RuntimeReflection.register(ReflectionUtil.lookupMethod(unsafeClass, "allocateInstance", Class.class));
}
}