1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mobile/android/thirdparty/ch/boye/httpclientandroidlib/client/entity/DeflateDecompressingEntity.java Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,174 @@
1.4 +/*
1.5 + * ====================================================================
1.6 + *
1.7 + * Licensed to the Apache Software Foundation (ASF) under one or more
1.8 + * contributor license agreements. See the NOTICE file distributed with
1.9 + * this work for additional information regarding copyright ownership.
1.10 + * The ASF licenses this file to You under the Apache License, Version 2.0
1.11 + * (the "License"); you may not use this file except in compliance with
1.12 + * the License. You may obtain a copy of the License at
1.13 + *
1.14 + * http://www.apache.org/licenses/LICENSE-2.0
1.15 + *
1.16 + * Unless required by applicable law or agreed to in writing, software
1.17 + * distributed under the License is distributed on an "AS IS" BASIS,
1.18 + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
1.19 + * See the License for the specific language governing permissions and
1.20 + * limitations under the License.
1.21 + * ====================================================================
1.22 + *
1.23 + * This software consists of voluntary contributions made by many
1.24 + * individuals on behalf of the Apache Software Foundation. For more
1.25 + * information on the Apache Software Foundation, please see
1.26 + * <http://www.apache.org/>.
1.27 + *
1.28 +*/
1.29 +package ch.boye.httpclientandroidlib.client.entity;
1.30 +
1.31 +import java.io.IOException;
1.32 +import java.io.InputStream;
1.33 +import java.io.PushbackInputStream;
1.34 +import java.util.zip.DataFormatException;
1.35 +import java.util.zip.Inflater;
1.36 +import java.util.zip.InflaterInputStream;
1.37 +
1.38 +import ch.boye.httpclientandroidlib.Header;
1.39 +import ch.boye.httpclientandroidlib.HttpEntity;
1.40 +import ch.boye.httpclientandroidlib.entity.HttpEntityWrapper;
1.41 +
1.42 +/**
1.43 + * {@link HttpEntityWrapper} responsible for handling deflate Content Coded responses. In RFC2616
1.44 + * terms, <code>deflate</code> means a <code>zlib</code> stream as defined in RFC1950. Some server
1.45 + * implementations have misinterpreted RFC2616 to mean that a <code>deflate</code> stream as
1.46 + * defined in RFC1951 should be used (or maybe they did that since that's how IE behaves?). It's
1.47 + * confusing that <code>deflate</code> in HTTP 1.1 means <code>zlib</code> streams rather than
1.48 + * <code>deflate</code> streams. We handle both types in here, since that's what is seen on the
1.49 + * internet. Moral - prefer <code>gzip</code>!
1.50 + *
1.51 + * @see GzipDecompressingEntity
1.52 + *
1.53 + * @since 4.1
1.54 + */
1.55 +public class DeflateDecompressingEntity extends DecompressingEntity {
1.56 +
1.57 + /**
1.58 + * Creates a new {@link DeflateDecompressingEntity} which will wrap the specified
1.59 + * {@link HttpEntity}.
1.60 + *
1.61 + * @param entity
1.62 + * a non-null {@link HttpEntity} to be wrapped
1.63 + */
1.64 + public DeflateDecompressingEntity(final HttpEntity entity) {
1.65 + super(entity);
1.66 + }
1.67 +
1.68 + /**
1.69 + * Returns the non-null InputStream that should be returned to by all requests to
1.70 + * {@link #getContent()}.
1.71 + *
1.72 + * @return a non-null InputStream
1.73 + * @throws IOException if there was a problem
1.74 + */
1.75 + @Override
1.76 + InputStream getDecompressingInputStream(final InputStream wrapped) throws IOException {
1.77 + /*
1.78 + * A zlib stream will have a header.
1.79 + *
1.80 + * CMF | FLG [| DICTID ] | ...compressed data | ADLER32 |
1.81 + *
1.82 + * * CMF is one byte.
1.83 + *
1.84 + * * FLG is one byte.
1.85 + *
1.86 + * * DICTID is four bytes, and only present if FLG.FDICT is set.
1.87 + *
1.88 + * Sniff the content. Does it look like a zlib stream, with a CMF, etc? c.f. RFC1950,
1.89 + * section 2.2. http://tools.ietf.org/html/rfc1950#page-4
1.90 + *
1.91 + * We need to see if it looks like a proper zlib stream, or whether it is just a deflate
1.92 + * stream. RFC2616 calls zlib streams deflate. Confusing, isn't it? That's why some servers
1.93 + * implement deflate Content-Encoding using deflate streams, rather than zlib streams.
1.94 + *
1.95 + * We could start looking at the bytes, but to be honest, someone else has already read
1.96 + * the RFCs and implemented that for us. So we'll just use the JDK libraries and exception
1.97 + * handling to do this. If that proves slow, then we could potentially change this to check
1.98 + * the first byte - does it look like a CMF? What about the second byte - does it look like
1.99 + * a FLG, etc.
1.100 + */
1.101 +
1.102 + /* We read a small buffer to sniff the content. */
1.103 + byte[] peeked = new byte[6];
1.104 +
1.105 + PushbackInputStream pushback = new PushbackInputStream(wrapped, peeked.length);
1.106 +
1.107 + int headerLength = pushback.read(peeked);
1.108 +
1.109 + if (headerLength == -1) {
1.110 + throw new IOException("Unable to read the response");
1.111 + }
1.112 +
1.113 + /* We try to read the first uncompressed byte. */
1.114 + byte[] dummy = new byte[1];
1.115 +
1.116 + Inflater inf = new Inflater();
1.117 +
1.118 + try {
1.119 + int n;
1.120 + while ((n = inf.inflate(dummy)) == 0) {
1.121 + if (inf.finished()) {
1.122 +
1.123 + /* Not expecting this, so fail loudly. */
1.124 + throw new IOException("Unable to read the response");
1.125 + }
1.126 +
1.127 + if (inf.needsDictionary()) {
1.128 +
1.129 + /* Need dictionary - then it must be zlib stream with DICTID part? */
1.130 + break;
1.131 + }
1.132 +
1.133 + if (inf.needsInput()) {
1.134 + inf.setInput(peeked);
1.135 + }
1.136 + }
1.137 +
1.138 + if (n == -1) {
1.139 + throw new IOException("Unable to read the response");
1.140 + }
1.141 +
1.142 + /*
1.143 + * We read something without a problem, so it's a valid zlib stream. Just need to reset
1.144 + * and return an unused InputStream now.
1.145 + */
1.146 + pushback.unread(peeked, 0, headerLength);
1.147 + return new InflaterInputStream(pushback);
1.148 + } catch (DataFormatException e) {
1.149 +
1.150 + /* Presume that it's an RFC1951 deflate stream rather than RFC1950 zlib stream and try
1.151 + * again. */
1.152 + pushback.unread(peeked, 0, headerLength);
1.153 + return new InflaterInputStream(pushback, new Inflater(true));
1.154 + }
1.155 + }
1.156 +
1.157 + /**
1.158 + * {@inheritDoc}
1.159 + */
1.160 + @Override
1.161 + public Header getContentEncoding() {
1.162 +
1.163 + /* This HttpEntityWrapper has dealt with the Content-Encoding. */
1.164 + return null;
1.165 + }
1.166 +
1.167 + /**
1.168 + * {@inheritDoc}
1.169 + */
1.170 + @Override
1.171 + public long getContentLength() {
1.172 +
1.173 + /* Length of inflated content is unknown. */
1.174 + return -1;
1.175 + }
1.176 +
1.177 +}
