/*

 * Copyright (c) 2016, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jshell.execution;

import java.io.File;

import java.net.URL;

import java.net.URLClassLoader;

import java.security.CodeSource;

import java.util.Map;

import java.util.TreeMap;

import jdk.jshell.spi.ExecutionControl.ClassBytecodes;

import jdk.jshell.spi.ExecutionControl.ClassInstallException;

import jdk.jshell.spi.ExecutionControl.EngineTerminationException;

import jdk.jshell.spi.ExecutionControl.InternalException;

import jdk.jshell.spi.ExecutionControl.NotImplementedException;

/**

 * The standard implementation of {@link LoaderDelegate} using

 * a {@link URLClassLoader}.

 *

 * @author Robert Field

 */

class DefaultLoaderDelegate implements LoaderDelegate {

    private final RemoteClassLoader loader;

    private final Map<String, Class<?>> klasses = new TreeMap<>();

    class RemoteClassLoader extends URLClassLoader {

        private final Map<String, byte[]> classObjects = new TreeMap<>();

        RemoteClassLoader() {

            super(new URL[0]);

        }

        void delare(String name, byte[] bytes) {

            classObjects.put(name, bytes);

        }

        @Override

        protected Class<?> findClass(String name) throws ClassNotFoundException {

            byte[] b = classObjects.get(name);

            if (b == null) {

                return super.findClass(name);

            }

            return super.defineClass(name, b, 0, b.length, (CodeSource) null);

        }

        @Override

        public void addURL(URL url) {

            super.addURL(url);

        }

    }

    public DefaultLoaderDelegate() {

        this.loader = new RemoteClassLoader();

        Thread.currentThread().setContextClassLoader(loader);

    }

    @Override

    public void load(ClassBytecodes[] cbcs)

            throws ClassInstallException, EngineTerminationException {

        boolean[] loaded = new boolean[cbcs.length];

        try {

            for (ClassBytecodes cbc : cbcs) {

                loader.delare(cbc.name(), cbc.bytecodes());

            }

            for (int i = 0; i < cbcs.length; ++i) {

                ClassBytecodes cbc = cbcs[i];

                Class<?> klass = loader.loadClass(cbc.name());

                klasses.put(cbc.name(), klass);

                loaded[i] = true;

                // Get class loaded to the point of, at least, preparation

                klass.getDeclaredMethods();

            }

        } catch (Throwable ex) {

            throw new ClassInstallException("load: " + ex.getMessage(), loaded);

        }

    }

    @Override

    public void addToClasspath(String cp)

            throws EngineTerminationException, InternalException {

        try {

            for (String path : cp.split(File.pathSeparator)) {

                loader.addURL(new File(path).toURI().toURL());

            }

        } catch (Exception ex) {

            throw new InternalException(ex.toString());

        }

    }

    @Override

    public Class<?> findClass(String name) throws ClassNotFoundException {

        Class<?> klass = klasses.get(name);

        if (klass == null) {

            throw new ClassNotFoundException(name + " not found");

        } else {

            return klass;

        }

    }

}