/*
 * Copyright (C) 2006 Sun Microsystems, Inc. All rights reserved. 
 * Use is subject to license terms.
 *
 * Redistribution and use in source and binary forms, with or without modification, are 
 * permitted provided that the following conditions are met: Redistributions of source code 
 * must retain the above copyright notice, this list of conditions and the following disclaimer.
 * 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. Neither the name of the Sun Microsystems nor the names of 
 * is contributors may be used to endorse or promote products derived from this software 
 * without specific prior written permission. 

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * 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 COPYRIGHT OWNER 
 * OR 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.
 */

/*
 * File sourced from: https://scripting.dev.java.net/source/browse/scripting/engines/java/src/com/sun/script/java/ 
 *
 * MemoryJavaFileManager.java
 * @author A. Sundararajan
 */

package org.nuiton.wikitty.publication.engine;

import java.io.*;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.CharBuffer;
import java.util.Map;
import java.util.HashMap;
import javax.tools.*;
import javax.tools.JavaFileObject.Kind;

/**
 * JavaFileManager that keeps compiled .class bytes in memory.
 */
public final class MemoryJavaFileManager extends ForwardingJavaFileManager {                 

    /** Java source file extension. */
    private final static String EXT = ".java";

    private Map<String, byte[]> classBytes;
    
    public MemoryJavaFileManager(JavaFileManager fileManager) {
        super(fileManager);
        classBytes = new HashMap<String, byte[]>();
    }

    public Map<String, byte[]> getClassBytes() {
        return classBytes;
    }
   
    public void close() throws IOException {
        classBytes = new HashMap<String, byte[]>();
    }

    public void flush() throws IOException {
    }

    /**
     * A file object used to represent Java source coming from a string.
     */
    private static class StringInputBuffer extends SimpleJavaFileObject {
        final String code;
        
        StringInputBuffer(String name, String code) {
            super(toURI(name), Kind.SOURCE);
            this.code = code;
        }
        
        public CharBuffer getCharContent(boolean ignoreEncodingErrors) {
            return CharBuffer.wrap(code);
        }

        public Reader openReader() {
            return new StringReader(code);
        }
    }

    /**
     * A file object that stores Java bytecode into the classBytes map.
     */
    private class ClassOutputBuffer extends SimpleJavaFileObject {
        private String name;

        ClassOutputBuffer(String name) { 
            super(toURI(name), Kind.CLASS);
            this.name = name;
        }

        public OutputStream openOutputStream() {
            return new FilterOutputStream(new ByteArrayOutputStream()) {
                public void close() throws IOException {
                    out.close();
                    ByteArrayOutputStream bos = (ByteArrayOutputStream)out;
                    classBytes.put(name, bos.toByteArray());
                }
            };
        }
    }
    
    public JavaFileObject getJavaFileForOutput(JavaFileManager.Location location,
                                    String className,
                                    Kind kind,
                                    FileObject sibling) throws IOException {
        if (kind == Kind.CLASS) {
            return new ClassOutputBuffer(className);
        } else {
            return super.getJavaFileForOutput(location, className, kind, sibling);
        }
    }

    static JavaFileObject makeStringSource(String name, String code) {
        return new StringInputBuffer(name, code);
    }

    static URI toURI(String name) {
        File file = new File(name);
        if (file.exists()) {
            return file.toURI();
        } else {
            try {
                final StringBuilder newUri = new StringBuilder();
                newUri.append("mfm:///");
                newUri.append(name.replace('.', '/'));
                if(name.endsWith(EXT)) newUri.replace(newUri.length() - EXT.length(), newUri.length(), EXT);
                return URI.create(newUri.toString());
            } catch (Exception exp) {
                return URI.create("mfm:///com/sun/script/java/java_source");
            }
        }
    }
}
