/*
* Copyright (C) 2010, Google Inc.
* 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.http.server;
import static org.eclipse.jgit.http.server.ServletUtils.acceptsGzipEncoding;
import static org.eclipse.jgit.util.HttpSupport.ENCODING_GZIP;
import static org.eclipse.jgit.util.HttpSupport.HDR_CONTENT_ENCODING;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jgit.util.TemporaryBuffer;
/**
* Buffers a response, trying to gzip it if the user agent supports that.
* <p>
* If the response overflows the buffer, gzip is skipped and the response is
* streamed to the client as its produced, most likely using HTTP/1.1 chunked
* encoding. This is useful for servlets that produce mixed-mode content, where
* smaller payloads are primarily pure text that compresses well, while much
* larger payloads are heavily compressed binary data. {@link UploadPackServlet}
* is one such servlet.
*/
class SmartOutputStream extends TemporaryBuffer {
private static final int LIMIT = 32 * 1024;
private final HttpServletRequest req;
private final HttpServletResponse rsp;
private boolean startedOutput;
SmartOutputStream(final HttpServletRequest req,
final HttpServletResponse rsp) {
super(LIMIT);
this.req = req;
this.rsp = rsp;
}
@Override
protected OutputStream overflow() throws IOException {
startedOutput = true;
return rsp.getOutputStream();
}
public void close() throws IOException {
super.close();
if (!startedOutput) {
// If output hasn't started yet, the entire thing fit into our
// buffer. Try to use a proper Content-Length header, and also
// deflate the response with gzip if it will be smaller.
TemporaryBuffer out = this;
if (256 < out.length() && acceptsGzipEncoding(req)) {
TemporaryBuffer gzbuf = new TemporaryBuffer.Heap(LIMIT);
try {
GZIPOutputStream gzip = new GZIPOutputStream(gzbuf);
try {
out.writeTo(gzip, null);
} finally {
gzip.close();
}
if (gzbuf.length() < out.length()) {
out = gzbuf;
rsp.setHeader(HDR_CONTENT_ENCODING, ENCODING_GZIP);
}
} catch (IOException err) {
// Most likely caused by overflowing the buffer, meaning
// its larger if it were compressed. Discard compressed
// copy and use the original.
}
}
// The Content-Length cannot overflow when cast to an int, our
// hardcoded LIMIT constant above assures us we wouldn't store
// more than 2 GiB of content in memory.
rsp.setContentLength((int) out.length());
final OutputStream os = rsp.getOutputStream();
try {
out.writeTo(os, null);
os.flush();
} finally {
os.close();
}
}
}
}