org.apache.poi.poifs.filesystem.POIFSFileSystem Maven / Gradle / Ivy
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/* ====================================================================
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==================================================================== */
package org.apache.poi.poifs.filesystem;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
import java.nio.channels.ReadableByteChannel;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.apache.poi.EmptyFileException;
import org.apache.poi.poifs.common.POIFSBigBlockSize;
import org.apache.poi.poifs.common.POIFSConstants;
import org.apache.poi.poifs.dev.POIFSViewable;
import org.apache.poi.poifs.nio.ByteArrayBackedDataSource;
import org.apache.poi.poifs.nio.DataSource;
import org.apache.poi.poifs.nio.FileBackedDataSource;
import org.apache.poi.poifs.property.DirectoryProperty;
import org.apache.poi.poifs.property.DocumentProperty;
import org.apache.poi.poifs.property.PropertyTable;
import org.apache.poi.poifs.storage.BATBlock;
import org.apache.poi.poifs.storage.BATBlock.BATBlockAndIndex;
import org.apache.poi.poifs.storage.HeaderBlock;
import org.apache.poi.util.IOUtils;
import org.apache.poi.util.Internal;
import org.apache.poi.util.POILogFactory;
import org.apache.poi.util.POILogger;
/**
* This is the main class of the POIFS system; it manages the entire
* life cycle of the filesystem.
* This is the new NIO version, which uses less memory
*/
public class POIFSFileSystem extends BlockStore
implements POIFSViewable, Closeable
{
//arbitrarily selected; may need to increase
private static final int MAX_RECORD_LENGTH = 100_000;
private static final POILogger LOG = POILogFactory.getLogger(POIFSFileSystem.class);
/**
* Maximum number size (in blocks) of the allocation table as supported by
* POI.
*
* This constant has been chosen to help POI identify corrupted data in the
* header block (rather than crash immediately with {@link OutOfMemoryError}
* ). It's not clear if the compound document format actually specifies any
* upper limits. For files with 512 byte blocks, having an allocation table
* of 65,335 blocks would correspond to a total file size of 4GB. Needless
* to say, POI probably cannot handle files anywhere near that size.
*/
private static final int MAX_BLOCK_COUNT = 65535;
private POIFSMiniStore _mini_store;
private PropertyTable _property_table;
private List _xbat_blocks;
private List _bat_blocks;
private HeaderBlock _header;
private DirectoryNode _root;
private DataSource _data;
/**
* What big block size the file uses. Most files
* use 512 bytes, but a few use 4096
*/
private POIFSBigBlockSize bigBlockSize =
POIFSConstants.SMALLER_BIG_BLOCK_SIZE_DETAILS;
private POIFSFileSystem(boolean newFS)
{
_header = new HeaderBlock(bigBlockSize);
_property_table = new PropertyTable(_header);
_mini_store = new POIFSMiniStore(this, _property_table.getRoot(), new ArrayList<>(), _header);
_xbat_blocks = new ArrayList<>();
_bat_blocks = new ArrayList<>();
_root = null;
if(newFS) {
// Data needs to initially hold just the header block,
// a single bat block, and an empty properties section
_data = new ByteArrayBackedDataSource(IOUtils.safelyAllocate(
bigBlockSize.getBigBlockSize()*3, MAX_RECORD_LENGTH));
}
}
/**
* Constructor, intended for writing
*/
public POIFSFileSystem()
{
this(true);
// Reserve block 0 for the start of the Properties Table
// Create a single empty BAT, at pop that at offset 1
_header.setBATCount(1);
_header.setBATArray(new int[] { 1 });
BATBlock bb = BATBlock.createEmptyBATBlock(bigBlockSize, false);
bb.setOurBlockIndex(1);
_bat_blocks.add(bb);
setNextBlock(0, POIFSConstants.END_OF_CHAIN);
setNextBlock(1, POIFSConstants.FAT_SECTOR_BLOCK);
_property_table.setStartBlock(0);
}
/**
* Creates a POIFSFileSystem from a File. This uses less memory than
* creating from an InputStream. The File will be opened read-only
*
* Note that with this constructor, you will need to call {@link #close()}
* when you're done to have the underlying file closed, as the file is
* kept open during normal operation to read the data out.
*
* @param file the File from which to read the data
*
* @exception IOException on errors reading, or on invalid data
*/
public POIFSFileSystem(File file)
throws IOException
{
this(file, true);
}
/**
* Creates a POIFSFileSystem from a File. This uses less memory than
* creating from an InputStream.
*
* Note that with this constructor, you will need to call {@link #close()}
* when you're done to have the underlying file closed, as the file is
* kept open during normal operation to read the data out.
*
* @param file the File from which to read or read/write the data
* @param readOnly whether the POIFileSystem will only be used in read-only mode
*
* @exception IOException on errors reading, or on invalid data
*/
public POIFSFileSystem(File file, boolean readOnly)
throws IOException
{
this(null, file, readOnly, true);
}
/**
* Creates a POIFSFileSystem from an open FileChannel. This uses
* less memory than creating from an InputStream. The stream will
* be used in read-only mode.
*
* Note that with this constructor, you will need to call {@link #close()}
* when you're done to have the underlying Channel closed, as the channel is
* kept open during normal operation to read the data out.
*
* @param channel the FileChannel from which to read the data
*
* @exception IOException on errors reading, or on invalid data
*/
public POIFSFileSystem(FileChannel channel)
throws IOException
{
this(channel, true);
}
/**
* Creates a POIFSFileSystem from an open FileChannel. This uses
* less memory than creating from an InputStream.
*
* Note that with this constructor, you will need to call {@link #close()}
* when you're done to have the underlying Channel closed, as the channel is
* kept open during normal operation to read the data out.
*
* @param channel the FileChannel from which to read or read/write the data
* @param readOnly whether the POIFileSystem will only be used in read-only mode
*
* @exception IOException on errors reading, or on invalid data
*/
public POIFSFileSystem(FileChannel channel, boolean readOnly)
throws IOException
{
this(channel, null, readOnly, false);
}
private POIFSFileSystem(FileChannel channel, File srcFile, boolean readOnly, boolean closeChannelOnError)
throws IOException
{
this(false);
try {
// Initialize the datasource
if (srcFile != null) {
if (srcFile.length() == 0)
throw new EmptyFileException();
FileBackedDataSource d = new FileBackedDataSource(srcFile, readOnly);
channel = d.getChannel();
_data = d;
} else {
_data = new FileBackedDataSource(channel, readOnly);
}
// Get the header
ByteBuffer headerBuffer = ByteBuffer.allocate(POIFSConstants.SMALLER_BIG_BLOCK_SIZE);
IOUtils.readFully(channel, headerBuffer);
// Have the header processed
_header = new HeaderBlock(headerBuffer);
// Now process the various entries
readCoreContents();
} catch(IOException | RuntimeException e) {
// Comes from Iterators etc.
// TODO Decide if we can handle these better whilst
// still sticking to the iterator contract
if (closeChannelOnError && channel != null) {
channel.close();
}
throw e;
}
}
/**
* Create a POIFSFileSystem from an InputStream. Normally the stream is read until
* EOF. The stream is always closed.
*
* Some streams are usable after reaching EOF (typically those that return true
* for markSupported()). In the unlikely case that the caller has such a stream
* and needs to use it after this constructor completes, a work around is to wrap the
* stream in order to trap the close() call. A convenience method (
* createNonClosingInputStream()) has been provided for this purpose:
*
* InputStream wrappedStream = POIFSFileSystem.createNonClosingInputStream(is);
* HSSFWorkbook wb = new HSSFWorkbook(wrappedStream);
* is.reset();
* doSomethingElse(is);
*
* Note also the special case of ByteArrayInputStream for which the close()
* method does nothing.
*
* ByteArrayInputStream bais = ...
* HSSFWorkbook wb = new HSSFWorkbook(bais); // calls bais.close() !
* bais.reset(); // no problem
* doSomethingElse(bais);
*
*
* @param stream the InputStream from which to read the data
*
* @exception IOException on errors reading, or on invalid data
*/
public POIFSFileSystem(InputStream stream)
throws IOException
{
this(false);
boolean success = false;
try (ReadableByteChannel channel = Channels.newChannel(stream)) {
// Turn our InputStream into something NIO based
// Get the header
ByteBuffer headerBuffer = ByteBuffer.allocate(POIFSConstants.SMALLER_BIG_BLOCK_SIZE);
IOUtils.readFully(channel, headerBuffer);
// Have the header processed
_header = new HeaderBlock(headerBuffer);
// Sanity check the block count
sanityCheckBlockCount(_header.getBATCount());
// We need to buffer the whole file into memory when
// working with an InputStream.
// The max possible size is when each BAT block entry is used
long maxSize = BATBlock.calculateMaximumSize(_header);
if (maxSize > Integer.MAX_VALUE) {
throw new IllegalArgumentException("Unable read a >2gb file via an InputStream");
}
ByteBuffer data = ByteBuffer.allocate((int) maxSize);
// Copy in the header
headerBuffer.position(0);
data.put(headerBuffer);
data.position(headerBuffer.capacity());
// Now read the rest of the stream
IOUtils.readFully(channel, data);
success = true;
// Turn it into a DataSource
_data = new ByteArrayBackedDataSource(data.array(), data.position());
} finally {
// As per the constructor contract, always close the stream
closeInputStream(stream, success);
}
// Now process the various entries
readCoreContents();
}
/**
* @param stream the stream to be closed
* @param success false if an exception is currently being thrown in the calling method
*/
private void closeInputStream(InputStream stream, boolean success) {
try {
stream.close();
} catch (IOException e) {
if(success) {
throw new RuntimeException(e);
}
// else not success? Try block did not complete normally
// just print stack trace and leave original ex to be thrown
LOG.log(POILogger.ERROR, "can't close input stream", e);
}
}
/**
* Read and process the PropertiesTable and the
* FAT / XFAT blocks, so that we're ready to
* work with the file
*/
private void readCoreContents() throws IOException {
// Grab the block size
bigBlockSize = _header.getBigBlockSize();
// Each block should only ever be used by one of the
// FAT, XFAT or Property Table. Ensure it does
ChainLoopDetector loopDetector = getChainLoopDetector();
// Read the FAT blocks
for(int fatAt : _header.getBATArray()) {
readBAT(fatAt, loopDetector);
}
// Work out how many FAT blocks remain in the XFATs
int remainingFATs = _header.getBATCount() - _header.getBATArray().length;
// Now read the XFAT blocks, and the FATs within them
BATBlock xfat;
int nextAt = _header.getXBATIndex();
for(int i=0; i<_header.getXBATCount(); i++) {
loopDetector.claim(nextAt);
ByteBuffer fatData = getBlockAt(nextAt);
xfat = BATBlock.createBATBlock(bigBlockSize, fatData);
xfat.setOurBlockIndex(nextAt);
nextAt = xfat.getValueAt(bigBlockSize.getXBATEntriesPerBlock());
_xbat_blocks.add(xfat);
// Process all the (used) FATs from this XFAT
int xbatFATs = Math.min(remainingFATs, bigBlockSize.getXBATEntriesPerBlock());
for(int j=0; j sbats = new ArrayList<>();
_mini_store = new POIFSMiniStore(this, _property_table.getRoot(), sbats, _header);
nextAt = _header.getSBATStart();
for(int i=0; i<_header.getSBATCount() && nextAt != POIFSConstants.END_OF_CHAIN; i++) {
loopDetector.claim(nextAt);
ByteBuffer fatData = getBlockAt(nextAt);
sfat = BATBlock.createBATBlock(bigBlockSize, fatData);
sfat.setOurBlockIndex(nextAt);
sbats.add(sfat);
nextAt = getNextBlock(nextAt);
}
}
private void readBAT(int batAt, ChainLoopDetector loopDetector) throws IOException {
loopDetector.claim(batAt);
ByteBuffer fatData = getBlockAt(batAt);
BATBlock bat = BATBlock.createBATBlock(bigBlockSize, fatData);
bat.setOurBlockIndex(batAt);
_bat_blocks.add(bat);
}
private BATBlock createBAT(int offset, boolean isBAT) throws IOException {
// Create a new BATBlock
BATBlock newBAT = BATBlock.createEmptyBATBlock(bigBlockSize, !isBAT);
newBAT.setOurBlockIndex(offset);
// Ensure there's a spot in the file for it
ByteBuffer buffer = ByteBuffer.allocate(bigBlockSize.getBigBlockSize());
int writeTo = (1+offset) * bigBlockSize.getBigBlockSize(); // Header isn't in BATs
_data.write(buffer, writeTo);
// All done
return newBAT;
}
/**
* Load the block at the given offset.
*/
@Override
protected ByteBuffer getBlockAt(final int offset) throws IOException {
// The header block doesn't count, so add one
long blockWanted = offset + 1L;
long startAt = blockWanted * bigBlockSize.getBigBlockSize();
try {
return _data.read(bigBlockSize.getBigBlockSize(), startAt);
} catch (IndexOutOfBoundsException e) {
IndexOutOfBoundsException wrapped = new IndexOutOfBoundsException("Block " + offset + " not found");
wrapped.initCause(e);
throw wrapped;
}
}
/**
* Load the block at the given offset,
* extending the file if needed
*/
@Override
protected ByteBuffer createBlockIfNeeded(final int offset) throws IOException {
try {
return getBlockAt(offset);
} catch(IndexOutOfBoundsException e) {
// The header block doesn't count, so add one
long startAt = (offset+1L) * bigBlockSize.getBigBlockSize();
// Allocate and write
ByteBuffer buffer = ByteBuffer.allocate(getBigBlockSize());
_data.write(buffer, startAt);
// Retrieve the properly backed block
return getBlockAt(offset);
}
}
/**
* Returns the BATBlock that handles the specified offset,
* and the relative index within it
*/
@Override
protected BATBlockAndIndex getBATBlockAndIndex(final int offset) {
return BATBlock.getBATBlockAndIndex(
offset, _header, _bat_blocks
);
}
/**
* Works out what block follows the specified one.
*/
@Override
protected int getNextBlock(final int offset) {
BATBlockAndIndex bai = getBATBlockAndIndex(offset);
return bai.getBlock().getValueAt( bai.getIndex() );
}
/**
* Changes the record of what block follows the specified one.
*/
@Override
protected void setNextBlock(final int offset, final int nextBlock) {
BATBlockAndIndex bai = getBATBlockAndIndex(offset);
bai.getBlock().setValueAt(
bai.getIndex(), nextBlock
);
}
/**
* Finds a free block, and returns its offset.
* This method will extend the file if needed, and if doing
* so, allocate new FAT blocks to address the extra space.
*/
@Override
protected int getFreeBlock() throws IOException {
int numSectors = bigBlockSize.getBATEntriesPerBlock();
// First up, do we have any spare ones?
int offset = 0;
for (BATBlock bat : _bat_blocks) {
if(bat.hasFreeSectors()) {
// Claim one of them and return it
for(int j=0; j= 109) {
// Needs to come from an XBAT
BATBlock xbat = null;
for(BATBlock x : _xbat_blocks) {
if(x.hasFreeSectors()) {
xbat = x;
break;
}
}
if(xbat == null) {
// Oh joy, we need a new XBAT too...
xbat = createBAT(offset+1, false);
// Allocate our new BAT as the first block in the XBAT
xbat.setValueAt(0, offset);
// And allocate the XBAT in the BAT
bat.setValueAt(1, POIFSConstants.DIFAT_SECTOR_BLOCK);
// Will go one place higher as XBAT added in
offset++;
// Chain it
if(_xbat_blocks.size() == 0) {
_header.setXBATStart(offset);
} else {
_xbat_blocks.get(_xbat_blocks.size()-1).setValueAt(
bigBlockSize.getXBATEntriesPerBlock(), offset
);
}
_xbat_blocks.add(xbat);
_header.setXBATCount(_xbat_blocks.size());
} else {
// Allocate our BAT in the existing XBAT with space
for(int i=0; i getViewableIterator() {
if (!preferArray()) {
return getRoot().getViewableIterator();
}
return Collections.emptyList().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 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 ********** */
/**
* @return The Big Block size, normally 512 bytes, sometimes 4096 bytes
*/
public int getBigBlockSize() {
return bigBlockSize.getBigBlockSize();
}
/**
* @return The Big Block size, normally 512 bytes, sometimes 4096 bytes
*/
@SuppressWarnings("WeakerAccess")
public POIFSBigBlockSize getBigBlockSizeDetails() {
return bigBlockSize;
}
/**
* Creates a new {@link POIFSFileSystem} in a new {@link File}.
* Use {@link #POIFSFileSystem(File)} to open an existing File,
* this should only be used to create a new empty filesystem.
*
* @param file The file to create and open
* @return The created and opened {@link POIFSFileSystem}
*/
public static POIFSFileSystem create(File file) throws IOException {
// Create a new empty POIFS in the file
try (POIFSFileSystem tmp = new POIFSFileSystem();
OutputStream out = new FileOutputStream(file)) {
tmp.writeFilesystem(out);
}
// Open it up again backed by the file
return new POIFSFileSystem(file, false);
}
@Override
protected int getBlockStoreBlockSize() {
return getBigBlockSize();
}
@Internal
public PropertyTable getPropertyTable() {
return _property_table;
}
@Internal
public HeaderBlock getHeaderBlock() {
return _header;
}
private static void sanityCheckBlockCount(int block_count) throws IOException {
if (block_count <= 0) {
throw new IOException(
"Illegal block count; minimum count is 1, got " +
block_count + " instead"
);
}
if (block_count > MAX_BLOCK_COUNT) {
throw new IOException(
"Block count " + block_count +
" is too high. POI maximum is " + MAX_BLOCK_COUNT + "."
);
}
}
}