/**
* Copyright (c) 2012, The National Archives <pronom@nationalarchives.gsi.gov.uk>
* All rights reserved.
*
* 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 The National Archives nor the
* names of its 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 HOLDER 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.
*/
package uk.gov.nationalarchives.droid.container;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import net.domesdaybook.reader.ByteReader;
import uk.gov.nationalarchives.droid.core.interfaces.IdentificationRequest;
import uk.gov.nationalarchives.droid.core.interfaces.RequestIdentifier;
import uk.gov.nationalarchives.droid.core.interfaces.archive.ArchiveFileUtils;
import uk.gov.nationalarchives.droid.core.interfaces.resource.CachedByteArray;
import uk.gov.nationalarchives.droid.core.interfaces.resource.CachedByteArrays;
import uk.gov.nationalarchives.droid.core.interfaces.resource.CachedBytes;
import uk.gov.nationalarchives.droid.core.interfaces.resource.ResourceUtils;
import uk.gov.nationalarchives.droid.core.interfaces.resource.RequestMetaData;
/**
* @author rflitcroft
*
*/
public class ContainerFileIdentificationRequest implements IdentificationRequest {
private static final int BUFFER_CACHE_CAPACITY = 10;
private static final int CAPACITY = 50 * 1024; // 50 kB
private Long size;
private CachedBytes cachedBinary;
private File tempFile;
private int lruCapacity;
private int bufferCapacity;
private File tempDir;
private Log log = LogFactory.getLog(this.getClass());
/**
* Constructs a new container file resource.
* @param tempDir the location to write temp files.
*/
public ContainerFileIdentificationRequest(File tempDir) {
this(BUFFER_CACHE_CAPACITY, CAPACITY, tempDir);
}
/**
* Constructs a new container file resource.
* @param lruCapacity the buffer cache capacity
* @param bufferCapacity the buffer capacity
* @param tempDir the location to write temp files.
*/
ContainerFileIdentificationRequest(int lruCapacity, int bufferCapacity, File tempDir) {
this.lruCapacity = lruCapacity;
this.bufferCapacity = bufferCapacity;
this.tempDir = tempDir;
}
/**
* {@inheritDoc}
*/
@Override
public final void open(InputStream in) throws IOException {
/* using normal stream access and CachedByteArrays */
byte[] firstBuffer = new byte[bufferCapacity];
int bytesRead = ResourceUtils.readBuffer(in, firstBuffer);
if (bytesRead < 1) {
firstBuffer = new byte[0];
cachedBinary = new CachedByteArray(firstBuffer, 0);
size = 0L;
} else if (bytesRead < bufferCapacity) {
// size the buffer to the amount of bytes available:
// firstBuffer = Arrays.copyOf(firstBuffer, bytesRead);
cachedBinary = new CachedByteArray(firstBuffer, bytesRead);
size = (long) bytesRead;
} else {
cachedBinary = new CachedByteArrays(lruCapacity, bufferCapacity, firstBuffer, bufferCapacity);
tempFile = ArchiveFileUtils.writeEntryToTemp(tempDir, firstBuffer, in);
cachedBinary.setSourceFile(tempFile);
size = tempFile.length();
}
/* using nio and cachedByteBufers
ReadableByteChannel channel = Channels.newChannel(in);
ByteBuffer buffer = ByteBuffer.allocate(bufferCapacity);
int bytesRead = 0;
do {
bytesRead = channel.read(buffer);
} while (bytesRead >= 0 && buffer.hasRemaining());
binaryCache = new CachedByteBuffers(lruCapacity, bufferCapacity, buffer);
if (buffer.limit() == buffer.capacity()) {
tempFile = ArchiveFileUtils.writeEntryToTemp(tempDir, buffer, channel);
binaryCache.setSourceFile(tempFile);
size = tempFile.length();
} else {
size = (long) buffer.limit();
}
*/
}
/**
* Releases resources for this resource.
* @throws IOException if the resource could not be closed
*/
@Override
public final void close() throws IOException {
try {
if (cachedBinary != null) {
cachedBinary.close();
cachedBinary = null;
}
} finally {
if (tempFile != null) {
if (!tempFile.delete() && tempFile.exists()) {
String message = String.format("Could not delete temporary file [%s] for container identification."
+ "Will try to delete on exit.",
tempFile.getAbsolutePath());
log.warn(message);
// only do this in extreme circumstances, or the app will leak memory until it closes down.
tempFile.deleteOnExit();
}
tempFile = null;
}
}
}
/**
* Really ensure that temporary files are deleted, if the close method is not called.
* Do not rely on this - this is just a double-double safety measure to avoid leaving
* temporary files hanging around.
* {@inheritDoc}
*/
@Override
//CHECKSTYLE:OFF
public void finalize() throws Throwable {
//CHECKSTYLE:ON
try {
close();
} finally {
super.finalize();
}
}
/**
* {@inheritDoc}
*/
@Override
public final byte getByte(long position) {
return cachedBinary.readByte(position);
}
/**
* {@inheritDoc}
*/
@Override
public final String getExtension() {
return null;
}
/**
* {@inheritDoc}
*/
@Override
public final String getFileName() {
return null;
}
/**
* {@inheritDoc}
*/
@Override
public final long size() {
return size;
}
/**
* @return the raf
*/
CachedBytes getCache() {
return cachedBinary;
}
/**
* {@inheritDoc}
* @throws IOException
*/
@Override
public final InputStream getSourceInputStream() throws IOException {
return cachedBinary.getSourceInputStream();
}
/**
* {@inheritDoc}
* @throws IOException
*/
@Override
public final File getSourceFile() throws IOException {
if (tempFile == null) {
final InputStream stream = cachedBinary.getSourceInputStream();
try {
tempFile = ResourceUtils.createTemporaryFileFromStream(tempDir, stream);
} finally {
if (stream != null) {
stream.close();
}
}
}
return tempFile;
}
/**
* @return the tempFile
*/
File getTempFile() {
return tempFile;
}
/**
* {@inheritDoc}
*/
@Override
public RequestMetaData getRequestMetaData() {
return null;
}
/**
* {@inheritDoc}
*/
@Override
public RequestIdentifier getIdentifier() {
return null;
}
/**
* {@inheritDoc}
*/
@Override
public final ByteReader getReader() {
return cachedBinary;
}
}