BEGIN LICENSE BLOCK *****
Version: EPL 2.0/GPL 2.0/LGPL 2.1
The contents of this file are subject to the Eclipse Public
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.eclipse.org/legal/epl-v20.html
Software distributed under the License is distributed on an "AS
IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
implied. See the License for the specific language governing
rights and limitations under the License.
Alternatively, the contents of this file may be used under the terms of
either of the GNU General Public License Version 2 or later (the "GPL"),
or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of either the GPL or the LGPL, and not to allow others to
use your version of this file under the terms of the EPL, indicate your
decision by deleting the provisions above and replace them with the notice
and other provisions required by the GPL or the LGPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the EPL, the GPL or the LGPL.
END LICENSE BLOCK /***** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * 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.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/
package org.jruby.util;

import org.objectweb.asm.ClassWriter;

ASM helpers for JRuby.
Author:
kares/**
 * ASM helpers for JRuby.
 *
 * @author kares
 */
public abstract class ASM {

    private ASM() { /* no instances */ }

    public static ClassWriter newClassWriter() {
        return new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
    }

    public static ClassWriter newClassWriter(ClassLoader loader) {
        return newClassWriter(loader, ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
    }

    public static ClassWriter newClassWriter(ClassLoader loader, final int flags) {
        return new ClassLoaderAwareWriter(loader, flags);
    }

    
NOTE: required to account for ASM calculating stack-map frames
in which case it might need to know of JRuby's dynamically loaded classes
Author:
kares/**
     * NOTE: required to account for ASM calculating stack-map frames
     * in which case it might need to know of JRuby's dynamically loaded classes
     *
     * @author kares
     */
    private static class ClassLoaderAwareWriter extends ClassWriter {

        private final ClassLoader loader;

        ClassLoaderAwareWriter(final ClassLoader loader, final int flags) {
            super(flags);
            this.loader = loader != null ? loader : ASM.class.getClassLoader();
        }

        @Override
        protected String getCommonSuperClass(String type1, String type2) {
            try {
                return getCommonSuperClassImpl(type1, type2, loader);
            }
            catch (TypeNotPresentException ex) {
                throw ex;
            }
        }

        private static String getCommonSuperClassImpl(String type1, String type2, final ClassLoader loader)
                throws TypeNotPresentException {
            Class<?> class1;
            try {
                class1 = Class.forName(type1.replace('/', '.'), false, loader);
            }
            catch (ClassNotFoundException|Error e) {
                throw new TypeNotPresentException(type1, e);
            }
            Class<?> class2;
            try {
                class2 = Class.forName(type2.replace('/', '.'), false, loader);
            }
            catch (ClassNotFoundException|Error e) {
                throw new TypeNotPresentException(type2, e);
            }
            if (class1.isAssignableFrom(class2)) {
                return type1;
            }
            if (class2.isAssignableFrom(class1)) {
                return type2;
            }
            if (class1.isInterface() || class2.isInterface()) {
                return "java/lang/Object";
            }
            do {
                class1 = class1.getSuperclass();
            }
            while (!class1.isAssignableFrom(class2));

            return class1.getName().replace('.', '/');
        }

    }

}