/*
 * FindBugs - Find Bugs in Java programs
 * Copyright (C) 2006-2007 University of Maryland
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.classfile.engine.asm;

import org.objectweb.asm.ClassReader;
import org.objectweb.asm.tree.ClassNode;

import edu.umd.cs.findbugs.classfile.CheckedAnalysisException;
import edu.umd.cs.findbugs.classfile.ClassDescriptor;
import edu.umd.cs.findbugs.classfile.IAnalysisCache;
import edu.umd.cs.findbugs.classfile.ICodeBaseEntry;
import edu.umd.cs.findbugs.classfile.InvalidClassFileFormatException;
import edu.umd.cs.findbugs.classfile.RecomputableClassAnalysisEngine;

/**
 * Analysis engine to produce the ClassNode (ASM tree format) for a class.
 * 
 * @author David Hovemeyer
 */
public class ClassNodeAnalysisEngine extends RecomputableClassAnalysisEngine<ClassNode> {

    /*
     * (non-Javadoc)
     * 
     * @see
     * edu.umd.cs.findbugs.classfile.IAnalysisEngine#analyze(edu.umd.cs.findbugs
     * .classfile.IAnalysisCache, java.lang.Object)
     */
    public ClassNode analyze(IAnalysisCache analysisCache, ClassDescriptor descriptor) throws CheckedAnalysisException {
        ClassReader classReader = analysisCache.getClassAnalysis(ClassReader.class, descriptor);

        ICodeBaseEntry entry = analysisCache.getClassPath().lookupResource(descriptor.toResourceName());

        // One of the less-than-ideal features of ASM is that
        // invalid classfile format is indicated by a
        // random runtime exception rather than something
        // indicative of the real problem.
        try {
            ClassNode cn = new ClassNode();
            classReader.accept(cn, 0);
            return cn;
        } catch (RuntimeException e) {
            throw new InvalidClassFileFormatException(descriptor, entry, e);
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * edu.umd.cs.findbugs.classfile.IAnalysisEngine#registerWith(edu.umd.cs
     * .findbugs.classfile.IAnalysisCache)
     */
    public void registerWith(IAnalysisCache analysisCache) {
        analysisCache.registerClassAnalysisEngine(ClassNode.class, this);
    }

}
