001/*
002 * Copyright (c) 2006-2012 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * All rights reserved. This program and the accompanying materials
005 * are made available under the terms of the Eclipse Public License v1.0
006 * which accompanies this distribution, and is available at
007 * http://www.eclipse.org/legal/epl-v10.html
008 *
009 * Contributors:
010 *     Florent Guillaume, jcarsique
011 */
012
013package org.nuxeo.ecm.core.blob.binary;
014
015import java.io.File;
016import java.io.IOException;
017import java.io.InputStream;
018
019import org.apache.commons.io.output.NullOutputStream;
020import org.nuxeo.ecm.core.api.Blob;
021import org.nuxeo.ecm.core.api.impl.blob.FileBlob;
022
023/**
024 * A simple filesystem-based binary manager. It stores the binaries according to their digest (hash), which means that
025 * no transactional behavior needs to be implemented.
026 * <p>
027 * A garbage collection is needed to purge unused binaries.
028 * <p>
029 * The format of the <em>binaries</em> directory is:
030 * <ul>
031 * <li><em>data/</em> hierarchy with the actual binaries in subdirectories,</li>
032 * <li><em>tmp/</em> temporary storage during creation,</li>
033 * <li><em>config.xml</em> a file containing the configuration used.</li>
034 * </ul>
035 *
036 * @author Florent Guillaume
037 */
038public class DefaultBinaryManager extends LocalBinaryManager {
039
040    @Override
041    public Binary getBinary(Blob blob) throws IOException {
042        if (!(blob instanceof FileBlob) || !((FileBlob) blob).isTemporary()) {
043            return super.getBinary(blob); // just open the stream
044        }
045        String digest = storeAndDigest((FileBlob) blob);
046        File file = getFileForDigest(digest, false);
047        /*
048         * Now we can build the Binary.
049         */
050        return new Binary(file, digest, blobProviderId);
051    }
052
053    /**
054     * Stores and digests a temporary FileBlob.
055     */
056    protected String storeAndDigest(FileBlob blob) throws IOException {
057        String digest;
058        try (InputStream in = blob.getStream()) {
059            digest = storeAndDigest(in, NullOutputStream.NULL_OUTPUT_STREAM);
060        }
061        File digestFile = getFileForDigest(digest, true);
062        if (digestFile.exists()) {
063            // The file with the proper digest is already there so don't do anything. This is to avoid
064            // "Stale NFS File Handle" problems which would occur if we tried to overwrite it anyway.
065            // Note that this doesn't try to protect from the case where two identical files are uploaded
066            // at the same time.
067            // Update date for the GC.
068            digestFile.setLastModified(blob.getFile().lastModified());
069        } else {
070            blob.moveTo(digestFile);
071        }
072        return digest;
073    }
074
075}