/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Ant", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.tools.ant.util.depend.bcel;
import java.io.File;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;
import org.apache.bcel.classfile.ClassParser;
import org.apache.bcel.classfile.JavaClass;
import org.apache.tools.ant.util.depend.AbstractAnalyzer;

/**
 * A dependency analyzer which returns superclass and superinterface
 * dependencies.
 *
 * @author Conor MacNeill
 */
public class AncestorAnalyzer extends AbstractAnalyzer {
    
    public AncestorAnalyzer() {
        // force BCEL classes to load now
        try {
            ClassParser parser = new ClassParser("force");
        } catch (IOException e) {
            // ignore
        }
    }
    
    /**
     * Determine the dependencies of the configured root classes.
     *
     * @param files a vector to be populated with the files which contain
     *      the dependency classes
     * @param classes a vector to be populated with the names of the
     *      depencency classes.
     */
    protected void determineDependencies(Vector files, Vector classes) {
        // we get the root classes and build up a set of
        // classes upon which they depend
        Hashtable dependencies = new Hashtable();
        Hashtable containers = new Hashtable();
        Hashtable toAnalyze = new Hashtable();
        Hashtable nextAnalyze = new Hashtable();
        for (Enumeration e = getRootClasses(); e.hasMoreElements();) {
            String classname = (String) e.nextElement();
            toAnalyze.put(classname, classname);
        }

        int count = 0;
        int maxCount = isClosureRequired() ? MAX_LOOPS : 2;
        while (toAnalyze.size() != 0 && count++ < maxCount) {
            nextAnalyze.clear();
            for (Enumeration e = toAnalyze.keys(); e.hasMoreElements();) {
                String classname = (String) e.nextElement();
                dependencies.put(classname, classname);
                try {
                    File container = getClassContainer(classname);
                    if (container == null) {
                        continue;
                    }
                    containers.put(container, container);

                    ClassParser parser = null;
                    if (container.getName().endsWith(".class")) {
                        parser = new ClassParser(container.getPath());
                    } else {
                        parser = new ClassParser(container.getPath(),
                            classname.replace('.', '/') + ".class");
                    }

                    JavaClass javaClass = parser.parse();
                    String[] interfaces = javaClass.getInterfaceNames();
                    for (int i = 0; i < interfaces.length; ++i) {
                        String interfaceName = interfaces[i];
                        if (!dependencies.containsKey(interfaceName)) {
                            nextAnalyze.put(interfaceName, interfaceName);
                        }
                    }

                    if (javaClass.isClass()) {
                        String superClass = javaClass.getSuperclassName();
                        if (!dependencies.containsKey(superClass)) {
                            nextAnalyze.put(superClass, superClass);
                        }
                    }
                } catch (IOException ioe) {
                    // ignore
                }
            }

            Hashtable temp = toAnalyze;
            toAnalyze = nextAnalyze;
            nextAnalyze = temp;
        }

        files.removeAllElements();
        for (Enumeration e = containers.keys(); e.hasMoreElements();) {
            files.addElement((File) e.nextElement());
        }

        classes.removeAllElements();
        for (Enumeration e = dependencies.keys(); e.hasMoreElements();) {
            classes.addElement((String) e.nextElement());
        }
    }

    /**
     * Indicate if this analyzer can determine dependent files.
     *
     * @return true if the analyzer provides dependency file information.
     */
    protected boolean supportsFileDependencies() {
        return true;
    }

}