1 /*
2 * Copyright (C) 2010, Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.http.server;
45
46 import static org.eclipse.jgit.http.server.ServletUtils.acceptsGzipEncoding;
47 import static org.eclipse.jgit.util.HttpSupport.ENCODING_GZIP;
48 import static org.eclipse.jgit.util.HttpSupport.HDR_CONTENT_ENCODING;
49
50 import java.io.IOException;
51 import java.io.OutputStream;
52 import java.util.zip.GZIPOutputStream;
53
54 import javax.servlet.http.HttpServletRequest;
55 import javax.servlet.http.HttpServletResponse;
56
57 import org.eclipse.jgit.util.TemporaryBuffer;
58
59 /**
60 * Buffers a response, trying to gzip it if the user agent supports that.
61 * <p>
62 * If the response overflows the buffer, gzip is skipped and the response is
63 * streamed to the client as its produced, most likely using HTTP/1.1 chunked
64 * encoding. This is useful for servlets that produce mixed-mode content, where
65 * smaller payloads are primarily pure text that compresses well, while much
66 * larger payloads are heavily compressed binary data. {@link UploadPackServlet}
67 * is one such servlet.
68 */
69 class SmartOutputStream extends TemporaryBuffer {
70 private static final int LIMIT = 32 * 1024;
71
72 private final HttpServletRequest req;
73 private final HttpServletResponse rsp;
74 private boolean compressStream;
75 private boolean startedOutput;
76
77 SmartOutputStream(final HttpServletRequest req,
78 final HttpServletResponse rsp,
79 boolean compressStream) {
80 super(LIMIT);
81 this.req = req;
82 this.rsp = rsp;
83 this.compressStream = compressStream;
84 }
85
86 /** {@inheritDoc} */
87 @Override
88 protected OutputStream overflow() throws IOException {
89 startedOutput = true;
90
91 OutputStream out = rsp.getOutputStream();
92 if (compressStream && acceptsGzipEncoding(req)) {
93 rsp.setHeader(HDR_CONTENT_ENCODING, ENCODING_GZIP);
94 out = new GZIPOutputStream(out);
95 }
96 return out;
97 }
98
99 /** {@inheritDoc} */
100 @Override
101 public void close() throws IOException {
102 super.close();
103
104 if (!startedOutput) {
105 // If output hasn't started yet, the entire thing fit into our
106 // buffer. Try to use a proper Content-Length header, and also
107 // deflate the response with gzip if it will be smaller.
108 TemporaryBuffer out = this;
109
110 if (256 < out.length() && acceptsGzipEncoding(req)) {
111 TemporaryBuffer gzbuf = new TemporaryBuffer.Heap(LIMIT);
112 try {
113 GZIPOutputStream gzip = new GZIPOutputStream(gzbuf);
114 try {
115 out.writeTo(gzip, null);
116 } finally {
117 gzip.close();
118 }
119 if (gzbuf.length() < out.length()) {
120 out = gzbuf;
121 rsp.setHeader(HDR_CONTENT_ENCODING, ENCODING_GZIP);
122 }
123 } catch (IOException err) {
124 // Most likely caused by overflowing the buffer, meaning
125 // its larger if it were compressed. Discard compressed
126 // copy and use the original.
127 }
128 }
129
130 // The Content-Length cannot overflow when cast to an int, our
131 // hardcoded LIMIT constant above assures us we wouldn't store
132 // more than 2 GiB of content in memory.
133 rsp.setContentLength((int) out.length());
134 final OutputStream os = rsp.getOutputStream();
135 try {
136 out.writeTo(os, null);
137 os.flush();
138 } finally {
139 os.close();
140 }
141 }
142 }
143 }