org.eclipse.jgit.lfs.server.fs.ObjectDownloadListener.java Source code

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Here is the source code for org.eclipse.jgit.lfs.server.fs.ObjectDownloadListener.java

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/*
 * Copyright (C) 2015, Matthias Sohn <matthias.sohn@sap.com>
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * 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 Eclipse Foundation, Inc. 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 OWNER 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 org.eclipse.jgit.lfs.server.fs;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.servlet.AsyncContext;
import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletResponse;

import org.apache.http.HttpStatus;
import org.eclipse.jgit.lfs.lib.AnyLongObjectId;
import org.eclipse.jgit.lfs.lib.Constants;
import org.eclipse.jgit.util.HttpSupport;

/**
 * Handle asynchronous large object download
 */
class ObjectDownloadListener implements WriteListener {

    private static Logger LOG = Logger.getLogger(ObjectDownloadListener.class.getName());

    private final AsyncContext context;

    private final HttpServletResponse response;

    private final ServletOutputStream out;

    private final ReadableByteChannel in;

    private final WritableByteChannel outChannel;

    private final ByteBuffer buffer = ByteBuffer.allocateDirect(8192);

    /**
     * @param repository
     *            the repository storing large objects
     * @param context
     *            the servlet asynchronous context
     * @param response
     *            the servlet response
     * @param id
     *            id of the object to be downloaded
     * @throws IOException
     */
    public ObjectDownloadListener(FileLfsRepository repository, AsyncContext context, HttpServletResponse response,
            AnyLongObjectId id) throws IOException {
        this.context = context;
        this.response = response;
        this.in = repository.getReadChannel(id);
        this.out = response.getOutputStream();
        this.outChannel = Channels.newChannel(out);

        response.addHeader(HttpSupport.HDR_CONTENT_LENGTH, String.valueOf(repository.getSize(id)));
        response.setContentType(Constants.HDR_APPLICATION_OCTET_STREAM);
    }

    /**
     * Write file content
     *
     * @throws IOException
     */
    @Override
    public void onWritePossible() throws IOException {
        while (out.isReady()) {
            if (in.read(buffer) != -1) {
                buffer.flip();
                outChannel.write(buffer);
                buffer.compact();
            } else {
                in.close();
                buffer.flip();
                while (out.isReady()) {
                    if (buffer.hasRemaining()) {
                        outChannel.write(buffer);
                    } else {
                        context.complete();
                    }
                }
            }
        }
    }

    /**
     * Handle errors
     *
     * @param e
     *            the cause
     */
    @Override
    public void onError(Throwable e) {
        try {
            FileLfsServlet.sendError(response, HttpStatus.SC_INTERNAL_SERVER_ERROR, e.getMessage());
            context.complete();
            in.close();
        } catch (IOException ex) {
            LOG.log(Level.SEVERE, ex.getMessage(), ex);
        }
    }
}