/*

 * Copyright (c) 2010, 2015, 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.

 *

 * 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.

 */

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.Reader;

import java.io.Writer;

import java.net.URI;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

import java.util.Objects;

import java.util.regex.Pattern;

import javax.lang.model.element.Modifier;

import javax.lang.model.element.NestingKind;

import javax.tools.JavaFileManager.Location;

import javax.tools.JavaFileObject;

import javax.tools.StandardJavaFileManager;

import com.sun.tools.javac.api.WrappingJavaFileManager;

/**

 * A JavaFileManager that can throw IOException on attempting to read or write

 * selected files that match a regular expression.

 */

public class FileManager

        extends WrappingJavaFileManager<StandardJavaFileManager>

        implements StandardJavaFileManager {

    private static final String CANT_READ = "cantRead:";

    private static final String CANT_WRITE = "cantWrite:";

    private Pattern cantRead;

    private Pattern cantWrite;

    public FileManager(StandardJavaFileManager fm, List<String> opts) {

        super(fm);

        for (String opt: opts) {

            if (opt.startsWith(CANT_READ))

                cantRead = Pattern.compile(opt.substring(CANT_READ.length()));

            else if (opt.startsWith(CANT_WRITE))

                cantWrite = Pattern.compile(opt.substring(CANT_WRITE.length()));

            else

                throw new IllegalArgumentException(opt);

        }

    }

    @Override

    protected JavaFileObject wrap(JavaFileObject fo) {

        return (fo == null) ? null : new WrappedFileObject(fo);

    }

    @Override

    protected JavaFileObject unwrap(JavaFileObject fo) {

        if (fo instanceof WrappedFileObject)

            return ((WrappedFileObject) fo).delegate;

        else

            return fo;

    }

    public Iterable<? extends JavaFileObject> getJavaFileObjectsFromFiles(Iterable<? extends File> files) {

        return wrap2(fileManager.getJavaFileObjectsFromFiles(files));

    }

    public Iterable<? extends JavaFileObject> getJavaFileObjects(File... files) {

        return wrap2(fileManager.getJavaFileObjects(files));

    }

    public Iterable<? extends JavaFileObject> getJavaFileObjectsFromStrings(Iterable<String> names) {

        return wrap2(fileManager.getJavaFileObjectsFromStrings(names));

    }

    public Iterable<? extends JavaFileObject> getJavaFileObjects(String... names) {

        return wrap2(fileManager.getJavaFileObjects(names));

    }

    /* This method is regrettably necessary because WrappingJavaFileManager.wrap takes

     *          Iterable<JavaFileObject> fileObjects

     * instead of

     *          Iterable<? extends JavaFileObject> fileObjects

     */

    protected Iterable<JavaFileObject> wrap2(Iterable<? extends JavaFileObject> fileObjects) {

        List<JavaFileObject> mapped = new ArrayList<JavaFileObject>();

        for (JavaFileObject fileObject : fileObjects)

            mapped.add(wrap(fileObject));

        return Collections.unmodifiableList(mapped);

    }

    public void setLocation(Location location, Iterable<? extends File> path) throws IOException {

        fileManager.setLocation(location, path);

    }

    public Iterable<? extends File> getLocation(Location location) {

        return fileManager.getLocation(location);

    }

    class WrappedFileObject implements JavaFileObject {

        WrappedFileObject(JavaFileObject fileObject) {

            delegate = Objects.requireNonNull(fileObject);

        }

        public Kind getKind() {

            return delegate.getKind();

        }

        public boolean isNameCompatible(String simpleName, Kind kind) {

            return delegate.isNameCompatible(simpleName, kind);

        }

        public NestingKind getNestingKind() {

            return delegate.getNestingKind();

        }

        public Modifier getAccessLevel() {

            return delegate.getAccessLevel();

        }

        public URI toUri() {

            return delegate.toUri();

        }

        public String getName() {

            return delegate.getName();

        }

        public InputStream openInputStream() throws IOException {

            checkRead();

            return delegate.openInputStream();

        }

        public OutputStream openOutputStream() throws IOException {

            checkWrite();

            return delegate.openOutputStream();

        }

        public Reader openReader(boolean ignoreEncodingErrors) throws IOException {

            checkRead();

            return delegate.openReader(ignoreEncodingErrors);

        }

        public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

            checkRead();

            return delegate.getCharContent(ignoreEncodingErrors);

        }

        public Writer openWriter() throws IOException {

            checkWrite();

            return delegate.openWriter();

        }

        public long getLastModified() {

            return delegate.getLastModified();

        }

        public boolean delete() {

            return delegate.delete();

        }

        void checkRead() throws IOException {

            String canonName = getName().replace(File.separatorChar, '/');

            if (cantRead != null && cantRead.matcher(canonName).matches())

                throw new IOException("FileManager: Can't read");

        }

        void checkWrite() throws IOException {

            String canonName = getName().replace(File.separatorChar, '/');

            if (cantWrite != null && cantWrite.matcher(canonName).matches())

                throw new IOException("FileManager: Can't write");

        }

        JavaFileObject delegate;

    }

}