org.apache.aries.spifly.statictool.StaticToolClassWriter Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of org.apache.aries.spifly.static.tool Show documentation

This tool does the weaving to support SPI ServiceLoader statically.

There is a newer version: 1.3.7

Show newest version

/*
 * 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.aries.spifly.statictool;

import org.objectweb.asm.ClassWriter;

/**
 * We need to override ASM's default behaviour in
 * {@link #getCommonSuperClass(String, String)} so that it accepts a custom
 * classloader that can also see the jar that is being processed.
 */
public final class StaticToolClassWriter extends ClassWriter {

    private static final String OBJECT_INTERNAL_NAME = "java/lang/Object";
    private final ClassLoader loader;

    public StaticToolClassWriter(int flags, ClassLoader loader) {
        super(flags);

        this.loader = loader;
    }

    /**
     * The implementation uses the classloader provided using the Constructor.
     *
     * This is a slight variation on ASM's default behaviour as that obtains the
     * classloader to use ASMs classloader.
     */
    @Override
    protected String getCommonSuperClass(final String type1, final String type2) {
        Class c, d;
        try {
            c = Class.forName(type1.replace('/', '.'), false, loader);
            d = Class.forName(type2.replace('/', '.'), false, loader);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

        if (c.isAssignableFrom(d)) {
            return type1;
        }
        if (d.isAssignableFrom(c)) {
            return type2;
        }

        if (c.isInterface() || d.isInterface()) {
            return OBJECT_INTERNAL_NAME;
        }

        do {
            c = c.getSuperclass();
        } while (!c.isAssignableFrom(d));

        return c.getName().replace('.', '/');
    }
}