src/java/org/apache/poi/poifs/filesystem/POIFSFileSystem.java

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2003 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 acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache POI" 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",
 *    "Apache POI", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * 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.poi.poifs.filesystem;

import java.io.*;

import java.util.*;

import org.apache.poi.poifs.common.POIFSConstants;
import org.apache.poi.poifs.dev.POIFSViewable;
import org.apache.poi.poifs.property.DirectoryProperty;
import org.apache.poi.poifs.property.DocumentProperty;
import org.apache.poi.poifs.property.Property;
import org.apache.poi.poifs.property.PropertyTable;
import org.apache.poi.poifs.storage.BATBlock;
import org.apache.poi.poifs.storage.BlockAllocationTableReader;
import org.apache.poi.poifs.storage.BlockAllocationTableWriter;
import org.apache.poi.poifs.storage.BlockList;
import org.apache.poi.poifs.storage.BlockWritable;
import org.apache.poi.poifs.storage.HeaderBlockReader;
import org.apache.poi.poifs.storage.HeaderBlockWriter;
import org.apache.poi.poifs.storage.RawDataBlock;
import org.apache.poi.poifs.storage.RawDataBlockList;
import org.apache.poi.poifs.storage.SmallBlockTableReader;
import org.apache.poi.poifs.storage.SmallBlockTableWriter;
import org.apache.poi.poifs.storage.SmallDocumentBlock;

/**
 * This is the main class of the POIFS system; it manages the entire
 * life cycle of the filesystem.
 *
 * @author Marc Johnson (mjohnson at apache dot org)
 */

public class POIFSFileSystem
    implements POIFSViewable
{
    private PropertyTable _property_table;
    private List          _documents;
    private DirectoryNode _root;

    /**
     * Constructor, intended for writing
     */

    public POIFSFileSystem()
    {
        _property_table = new PropertyTable();
        _documents      = new ArrayList();
        _root           = null;
    }

    /**
     * Create a POIFSFileSystem from an InputStream
     *
     * @param stream the InputStream from which to read the data
     *
     * @exception IOException on errors reading, or on invalid data
     */

    public POIFSFileSystem(final InputStream stream)
        throws IOException
    {
        this();

        // read the header block from the stream
        HeaderBlockReader header_block_reader = new HeaderBlockReader(stream);

        // read the rest of the stream into blocks
        RawDataBlockList  data_blocks         = new RawDataBlockList(stream);

        // set up the block allocation table (necessary for the
        // data_blocks to be manageable
        new BlockAllocationTableReader(header_block_reader.getBATCount(),
                                       header_block_reader.getBATArray(),
                                       header_block_reader.getXBATCount(),
                                       header_block_reader.getXBATIndex(),
                                       data_blocks);

        // get property table from the document
        PropertyTable properties =
            new PropertyTable(header_block_reader.getPropertyStart(),
                              data_blocks);

        // init documents
        processProperties(SmallBlockTableReader
            .getSmallDocumentBlocks(data_blocks, properties
                .getRoot(), header_block_reader
                    .getSBATStart()), data_blocks, properties.getRoot()
                        .getChildren(), null);
    }

    /**
     * Create a new document to be added to the root directory
     *
     * @param stream the InputStream from which the document's data
     *               will be obtained
     * @param name the name of the new POIFSDocument
     *
     * @return the new DocumentEntry
     *
     * @exception IOException on error creating the new POIFSDocument
     */

    public DocumentEntry createDocument(final InputStream stream,
                                        final String name)
        throws IOException
    {
        return getRoot().createDocument(name, stream);
    }

    /**
     * create a new DocumentEntry in the root entry; the data will be
     * provided later
     *
     * @param name the name of the new DocumentEntry
     * @param size the size of the new DocumentEntry
     * @param writer the writer of the new DocumentEntry
     *
     * @return the new DocumentEntry
     *
     * @exception IOException
     */

    public DocumentEntry createDocument(final String name, final int size,
                                        final POIFSWriterListener writer)
        throws IOException
    {
        return getRoot().createDocument(name, size, writer);
    }

    /**
     * create a new DirectoryEntry in the root directory
     *
     * @param name the name of the new DirectoryEntry
     *
     * @return the new DirectoryEntry
     *
     * @exception IOException on name duplication
     */

    public DirectoryEntry createDirectory(final String name)
        throws IOException
    {
        return getRoot().createDirectory(name);
    }

    /**
     * Write the filesystem out
     *
     * @param stream the OutputStream to which the filesystem will be
     *               written
     *
     * @exception IOException thrown on errors writing to the stream
     */

    public void writeFilesystem(final OutputStream stream)
        throws IOException
    {

        // get the property table ready
        _property_table.preWrite();

        // create the small block store, and the SBAT
        SmallBlockTableWriter      sbtw       =
            new SmallBlockTableWriter(_documents, _property_table.getRoot());

        // create the block allocation table
        BlockAllocationTableWriter bat        =
            new BlockAllocationTableWriter();

        // create a list of BATManaged objects: the documents plus the
        // property table and the small block table
        List                       bm_objects = new ArrayList();

        bm_objects.addAll(_documents);
        bm_objects.add(_property_table);
        bm_objects.add(sbtw);
        bm_objects.add(sbtw.getSBAT());

        // walk the list, allocating space for each and assigning each
        // a starting block number
        Iterator iter = bm_objects.iterator();

        while (iter.hasNext())
        {
            BATManaged bmo         = ( BATManaged ) iter.next();
            int        block_count = bmo.countBlocks();

            if (block_count != 0)
            {
                bmo.setStartBlock(bat.allocateSpace(block_count));
            }
            else
            {

                // Either the BATManaged object is empty or its data
                // is composed of SmallBlocks; in either case,
                // allocating space in the BAT is inappropriate
            }
        }

        // allocate space for the block allocation table and take its
        // starting block
        int               batStartBlock       = bat.createBlocks();

        // get the extended block allocation table blocks
        HeaderBlockWriter header_block_writer = new HeaderBlockWriter();
        BATBlock[]        xbat_blocks         =
            header_block_writer.setBATBlocks(bat.countBlocks(),
                                             batStartBlock);

        // set the property table start block
        header_block_writer.setPropertyStart(_property_table.getStartBlock());

        // set the small block allocation table start block
        header_block_writer.setSBATStart(sbtw.getSBAT().getStartBlock());

        // set the small block allocation table block count
        header_block_writer.setSBATBlockCount(sbtw.getSBATBlockCount());

        // the header is now properly initialized. Make a list of
        // writers (the header block, followed by the documents, the
        // property table, the small block store, the small block
        // allocation table, the block allocation table, and the
        // extended block allocation table blocks)
        List writers = new ArrayList();

        writers.add(header_block_writer);
        writers.addAll(_documents);
        writers.add(_property_table);
        writers.add(sbtw);
        writers.add(sbtw.getSBAT());
        writers.add(bat);
        for (int j = 0; j < xbat_blocks.length; j++)
        {
            writers.add(xbat_blocks[ j ]);
        }

        // now, write everything out
        iter = writers.iterator();
        while (iter.hasNext())
        {
            BlockWritable writer = ( BlockWritable ) iter.next();

            writer.writeBlocks(stream);
        }
    }

    /**
     * read in a file and write it back out again
     *
     * @param args names of the files; arg[ 0 ] is the input file,
     *             arg[ 1 ] is the output file
     *
     * @exception IOException
     */

    public static void main(String args[])
        throws IOException
    {
        if (args.length != 2)
        {
            System.err.println(
                "two arguments required: input filename and output filename");
            System.exit(1);
        }
        FileInputStream  istream = new FileInputStream(args[ 0 ]);
        FileOutputStream ostream = new FileOutputStream(args[ 1 ]);

        new POIFSFileSystem(istream).writeFilesystem(ostream);
        istream.close();
        ostream.close();
    }

    /**
     * get the root entry
     *
     * @return the root entry
     */

    public DirectoryEntry getRoot()
    {
        if (_root == null)
        {
            _root = new DirectoryNode(_property_table.getRoot(), this, null);
        }
        return _root;
    }

    /**
     * open a document in the root entry's list of entries
     *
     * @param documentName the name of the document to be opened
     *
     * @return a newly opened DocumentInputStream
     *
     * @exception IOException if the document does not exist or the
     *            name is that of a DirectoryEntry
     */

    public DocumentInputStream createDocumentInputStream(
            final String documentName)
        throws IOException
    {
        Entry document = getRoot().getEntry(documentName);

        if (!document.isDocumentEntry())
        {
            throw new IOException("Entry '" + documentName
                                  + "' is not a DocumentEntry");
        }
        return new DocumentInputStream(( DocumentEntry ) document);
    }

    /**
     * add a new POIFSDocument
     *
     * @param document the POIFSDocument being added
     */

    void addDocument(final POIFSDocument document)
    {
        _documents.add(document);
        _property_table.addProperty(document.getDocumentProperty());
    }

    /**
     * add a new DirectoryProperty
     *
     * @param directory the DirectoryProperty being added
     */

    void addDirectory(final DirectoryProperty directory)
    {
        _property_table.addProperty(directory);
    }

    /**
     * remove an entry
     *
     * @param entry to be removed
     */

    void remove(EntryNode entry)
    {
        _property_table.removeProperty(entry.getProperty());
        if (entry.isDocumentEntry())
        {
            _documents.remove((( DocumentNode ) entry).getDocument());
        }
    }

    private void processProperties(final BlockList small_blocks,
                                   final BlockList big_blocks,
                                   final Iterator properties,
                                   final DirectoryNode dir)
        throws IOException
    {
        while (properties.hasNext())
        {
            Property      property = ( Property ) properties.next();
            String        name     = property.getName();
            DirectoryNode parent   = (dir == null)
                                     ? (( DirectoryNode ) getRoot())
                                     : dir;

            if (property.isDirectory())
            {
                DirectoryNode new_dir =
                    ( DirectoryNode ) parent.createDirectory(name);

                new_dir.setStorageClsid( property.getStorageClsid() );

                processProperties(
                    small_blocks, big_blocks,
                    (( DirectoryProperty ) property).getChildren(), new_dir);
            }
            else
            {
                int           startBlock = property.getStartBlock();
                int           size       = property.getSize();
                POIFSDocument document   = null;

                if (property.shouldUseSmallBlocks())
                {
                    document =
                        new POIFSDocument(name, small_blocks
                            .fetchBlocks(startBlock), size);
                }
                else
                {
                    document =
                        new POIFSDocument(name,
                                          big_blocks.fetchBlocks(startBlock),
                                          size);
                }
                parent.createDocument(document);
            }
        }
    }

    /* ********** START begin implementation of POIFSViewable ********** */

    /**
     * Get an array of objects, some of which may implement
     * POIFSViewable
     *
     * @return an array of Object; may not be null, but may be empty
     */

    public Object [] getViewableArray()
    {
        if (preferArray())
        {
            return (( POIFSViewable ) getRoot()).getViewableArray();
        }
        else
        {
            return new Object[ 0 ];
        }
    }

    /**
     * Get an Iterator of objects, some of which may implement
     * POIFSViewable
     *
     * @return an Iterator; may not be null, but may have an empty
     * back end store
     */

    public Iterator getViewableIterator()
    {
        if (!preferArray())
        {
            return (( POIFSViewable ) getRoot()).getViewableIterator();
        }
        else
        {
            return Collections.EMPTY_LIST.iterator();
        }
    }

    /**
     * Give viewers a hint as to whether to call getViewableArray or
     * getViewableIterator
     *
     * @return true if a viewer should call getViewableArray, false if
     *         a viewer should call getViewableIterator
     */

    public boolean preferArray()
    {
        return (( POIFSViewable ) getRoot()).preferArray();
    }

    /**
     * Provides a short description of the object, to be used when a
     * POIFSViewable object has not provided its contents.
     *
     * @return short description
     */

    public String getShortDescription()
    {
        return "POIFS FileSystem";
    }

    /* **********  END  begin implementation of POIFSViewable ********** */
}   // end public class POIFSFileSystem