/*
 * Copyright (c) 1997, 2017, 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
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package javax.activation;

import java.io.*;
import java.net.*;
import java.util.*;
import java.security.AccessController;
import java.security.PrivilegedAction;
import com.sun.activation.registries.MimeTypeFile;
import com.sun.activation.registries.LogSupport;

/**
 * This class extends FileTypeMap and provides data typing of files
 * via their file extension. It uses the {@code .mime.types} format. <p>
 *
 * <b>MIME types file search order:</b><p>
 * The MimetypesFileTypeMap looks in various places in the user's
 * system for MIME types file entries. When requests are made
 * to search for MIME types in the MimetypesFileTypeMap, it searches
 * MIME types files in the following order:
 * <ol>
 * <li> Programmatically added entries to the MimetypesFileTypeMap instance.
 * <li> The file {@code .mime.types} in the user's home directory.
 * <li> The file {@code mime.types} in the Java runtime.
 * <li> The file or resources named {@code META-INF/mime.types}.
 * <li> The file or resource named {@code META-INF/mimetypes.default}
 * (usually found only in the {@code activation.jar} file).
 * </ol>
 * <p>
 * (The current implementation looks for the {@code mime.types} file
 * in the Java runtime in the directory <i>java.home</i>{@code /conf}
 * if it exists, and otherwise in the directory
 * <i>java.home</i>{@code /lib}, where <i>java.home</i> is the value
 * of the "java.home" System property.  Note that the "conf" directory was
 * introduced in JDK 9.)
 * <p>
 * <b>MIME types file format:</b>
 *
 * <pre>{@code
 * # comments begin with a '#'
 * # the format is <mime type> <space separated file extensions>
 * # for example:
 * text/plain    txt text TXT
 * # this would map file.txt, file.text, and file.TXT to
 * # the mime type "text/plain"
 * }</pre>
 *
 * @author Bart Calder
 * @author Bill Shannon
 *
 * @since 1.6
 */
public class MimetypesFileTypeMap extends FileTypeMap {
    /*
     * We manage a collection of databases, searched in order.
     */
    private MimeTypeFile[] DB;
    private static final int PROG = 0;  // programmatically added entries

    private static final String defaultType = "application/octet-stream";

    private static final String confDir;

    static {
        String dir = null;
        try {
            dir = (String)AccessController.doPrivileged(
                new PrivilegedAction() {
                    public Object run() {
                        String home = System.getProperty("java.home");
                        String newdir = home + File.separator + "conf";
                        File conf = new File(newdir);
                        if (conf.exists())
                            return newdir + File.separator;
                        else
                            return home + File.separator + "lib" + File.separator;
                    }
                });
        } catch (Exception ex) {
            // ignore any exceptions
        }
        confDir = dir;
    }

    /**
     * The default constructor.
     */
    public MimetypesFileTypeMap() {
        Vector dbv = new Vector(5);     // usually 5 or less databases
        MimeTypeFile mf = null;
        dbv.addElement(null);           // place holder for PROG entry

        LogSupport.log("MimetypesFileTypeMap: load HOME");
        try {
            String user_home = System.getProperty("user.home");

            if (user_home != null) {
                String path = user_home + File.separator + ".mime.types";
                mf = loadFile(path);
                if (mf != null)
                    dbv.addElement(mf);
            }
        } catch (SecurityException ex) {}

        LogSupport.log("MimetypesFileTypeMap: load SYS");
        try {
            // check system's home
            if (confDir != null) {
                mf = loadFile(confDir + "mime.types");
                if (mf != null)
                    dbv.addElement(mf);
            }
        } catch (SecurityException ex) {}

        LogSupport.log("MimetypesFileTypeMap: load JAR");
        // load from the app's jar file
        loadAllResources(dbv, "META-INF/mime.types");

        LogSupport.log("MimetypesFileTypeMap: load DEF");
        mf = loadResource("/META-INF/mimetypes.default");

        if (mf != null)
            dbv.addElement(mf);

        DB = new MimeTypeFile[dbv.size()];
        dbv.copyInto(DB);
    }

    /**
     * Load from the named resource.
     */
    private MimeTypeFile loadResource(String name) {
        InputStream clis = null;
        try {
            clis = SecuritySupport.getResourceAsStream(this.getClass(), name);
            if (clis != null) {
                MimeTypeFile mf = new MimeTypeFile(clis);
                if (LogSupport.isLoggable())
                    LogSupport.log("MimetypesFileTypeMap: successfully " +
                        "loaded mime types file: " + name);
                return mf;
            } else {
                if (LogSupport.isLoggable())
                    LogSupport.log("MimetypesFileTypeMap: not loading " +
                        "mime types file: " + name);
            }
        } catch (IOException e) {
            if (LogSupport.isLoggable())
                LogSupport.log("MimetypesFileTypeMap: can't load " + name, e);
        } catch (SecurityException sex) {
            if (LogSupport.isLoggable())
                LogSupport.log("MimetypesFileTypeMap: can't load " + name, sex);
        } finally {
            try {
                if (clis != null)
                    clis.close();
            } catch (IOException ex) { }        // ignore it
        }
        return null;
    }

    /**
     * Load all of the named resource.
     */
    private void loadAllResources(Vector v, String name) {
        boolean anyLoaded = false;
        try {
            URL[] urls;
            ClassLoader cld = null;
            // First try the "application's" class loader.
            cld = SecuritySupport.getContextClassLoader();
            if (cld == null)
                cld = this.getClass().getClassLoader();
            if (cld != null)
                urls = SecuritySupport.getResources(cld, name);
            else
                urls = SecuritySupport.getSystemResources(name);
            if (urls != null) {
                if (LogSupport.isLoggable())
                    LogSupport.log("MimetypesFileTypeMap: getResources");
                for (int i = 0; i < urls.length; i++) {
                    URL url = urls[i];
                    InputStream clis = null;
                    if (LogSupport.isLoggable())
                        LogSupport.log("MimetypesFileTypeMap: URL " + url);
                    try {
                        clis = SecuritySupport.openStream(url);
                        if (clis != null) {
                            v.addElement(new MimeTypeFile(clis));
                            anyLoaded = true;
                            if (LogSupport.isLoggable())
                                LogSupport.log("MimetypesFileTypeMap: " +
                                    "successfully loaded " +
                                    "mime types from URL: " + url);
                        } else {
                            if (LogSupport.isLoggable())
                                LogSupport.log("MimetypesFileTypeMap: " +
                                    "not loading " +
                                    "mime types from URL: " + url);
                        }
                    } catch (IOException ioex) {
                        if (LogSupport.isLoggable())
                            LogSupport.log("MimetypesFileTypeMap: can't load " +
                                                url, ioex);
                    } catch (SecurityException sex) {
                        if (LogSupport.isLoggable())
                            LogSupport.log("MimetypesFileTypeMap: can't load " +
                                                url, sex);
                    } finally {
                        try {
                            if (clis != null)
                                clis.close();
                        } catch (IOException cex) { }
                    }
                }
            }
        } catch (Exception ex) {
            if (LogSupport.isLoggable())
                LogSupport.log("MimetypesFileTypeMap: can't load " + name, ex);
        }

        // if failed to load anything, fall back to old technique, just in case
        if (!anyLoaded) {
            LogSupport.log("MimetypesFileTypeMap: !anyLoaded");
            MimeTypeFile mf = loadResource("/" + name);
            if (mf != null)
                v.addElement(mf);
        }
    }

    /**
     * Load the named file.
     */
    private MimeTypeFile loadFile(String name) {
        MimeTypeFile mtf = null;

        try {
            mtf = new MimeTypeFile(name);
        } catch (IOException e) {
            //  e.printStackTrace();
        }
        return mtf;
    }

    /**
     * Construct a MimetypesFileTypeMap with programmatic entries
     * added from the named file.
     *
     * @param mimeTypeFileName  the file name
     * @exception       IOException     for errors reading the file
     */
    public MimetypesFileTypeMap(String mimeTypeFileName) throws IOException {
        this();
        DB[PROG] = new MimeTypeFile(mimeTypeFileName);
    }

    /**
     * Construct a MimetypesFileTypeMap with programmatic entries
     * added from the InputStream.
     *
     * @param is        the input stream to read from
     */
    public MimetypesFileTypeMap(InputStream is) {
        this();
        try {
            DB[PROG] = new MimeTypeFile(is);
        } catch (IOException ex) {
            // XXX - really should throw it
        }
    }

    /**
     * Prepend the MIME type values to the registry.
     *
     * @param mime_types A .mime.types formatted string of entries.
     */
    public synchronized void addMimeTypes(String mime_types) {
        // check to see if we have created the registry
        if (DB[PROG] == null)
            DB[PROG] = new MimeTypeFile(); // make one

        DB[PROG].appendToRegistry(mime_types);
    }

    /**
     * Return the MIME type of the file object.
     * The implementation in this class calls
     * {@code getContentType(f.getName())}.
     *
     * @param f the file
     * @return  the file's MIME type
     */
    public String getContentType(File f) {
        return this.getContentType(f.getName());
    }

    /**
     * Return the MIME type based on the specified file name.
     * The MIME type entries are searched as described above under
     * <i>MIME types file search order</i>.
     * If no entry is found, the type "application/octet-stream" is returned.
     *
     * @param filename  the file name
     * @return          the file's MIME type
     */
    public synchronized String getContentType(String filename) {
        int dot_pos = filename.lastIndexOf("."); // period index

        if (dot_pos < 0)
            return defaultType;

        String file_ext = filename.substring(dot_pos + 1);
        if (file_ext.length() == 0)
            return defaultType;

        for (int i = 0; i < DB.length; i++) {
            if (DB[i] == null)
                continue;
            String result = DB[i].getMIMETypeString(file_ext);
            if (result != null)
                return result;
        }
        return defaultType;
    }

    /**
     * for debugging...
     *
    public static void main(String[] argv) throws Exception {
        MimetypesFileTypeMap map = new MimetypesFileTypeMap();
        System.out.println("File " + argv[0] + " has MIME type " +
                                                map.getContentType(argv[0]));
        System.exit(0);
    }
    */
}