1 /*
   2  * Copyright (c) 1996, 2001, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package sun.rmi.transport.proxy;
  26 
  27 import java.io.*;
  28 
  29 import sun.rmi.runtime.Log;
  30 
  31 /**
  32  * The HttpInputStream class assists the HttpSendSocket and HttpReceiveSocket
  33  * classes by filtering out the header for the message as well as any
  34  * data after its proper content length.
  35  */
  36 class HttpInputStream extends FilterInputStream {
  37 
  38     /** bytes remaining to be read from proper content of message */
  39     protected int bytesLeft;
  40 
  41     /** bytes remaining to be read at time of last mark */
  42     protected int bytesLeftAtMark;
  43 
  44     /**
  45      * Create new filter on a given input stream.
  46      * @param in the InputStream to filter from
  47      */
  48     public HttpInputStream(InputStream in) throws IOException
  49     {
  50         super(in);
  51 
  52         if (in.markSupported())
  53             in.mark(0); // prevent resetting back to old marks
  54 
  55         // pull out header, looking for content length
  56 
  57         DataInputStream dis = new DataInputStream(in);
  58         String key = "Content-length:".toLowerCase();
  59         boolean contentLengthFound = false;
  60         String line;
  61         do {
  62             line = dis.readLine();
  63 
  64             if (RMIMasterSocketFactory.proxyLog.isLoggable(Log.VERBOSE)) {
  65                 RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,
  66                     "received header line: \"" + line + "\"");
  67             }
  68 
  69             if (line == null)
  70                 throw new EOFException();
  71 
  72             if (line.toLowerCase().startsWith(key)) {
  73                 if (contentLengthFound)
  74                     ; // what would we want to do in this case??
  75                 bytesLeft =
  76                     Integer.parseInt(line.substring(key.length()).trim());
  77                 contentLengthFound = true;
  78             }
  79 
  80             // The idea here is to go past the first blank line.
  81             // Some DataInputStream.readLine() documentation specifies that
  82             // it does include the line-terminating character(s) in the
  83             // returned string, but it actually doesn't, so we'll cover
  84             // all cases here...
  85         } while ((line.length() != 0) &&
  86                  (line.charAt(0) != '\r') && (line.charAt(0) != '\n'));
  87 
  88         if (!contentLengthFound || bytesLeft < 0) {
  89             // This really shouldn't happen, but if it does, shoud we fail??
  90             // For now, just give up and let a whole lot of bytes through...
  91             bytesLeft = Integer.MAX_VALUE;
  92         }
  93         bytesLeftAtMark = bytesLeft;
  94 
  95         if (RMIMasterSocketFactory.proxyLog.isLoggable(Log.VERBOSE)) {
  96             RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,
  97                 "content length: " + bytesLeft);
  98         }
  99     }
 100 
 101     /**
 102      * Returns the number of bytes that can be read with blocking.
 103      * Make sure that this does not exceed the number of bytes remaining
 104      * in the proper content of the message.
 105      */
 106     public int available() throws IOException
 107     {
 108         int bytesAvailable = in.available();
 109         if (bytesAvailable > bytesLeft)
 110             bytesAvailable = bytesLeft;
 111 
 112         return bytesAvailable;
 113     }
 114 
 115     /**
 116      * Read a byte of data from the stream.  Make sure that one is available
 117      * from the proper content of the message, else -1 is returned to
 118      * indicate to the user that the end of the stream has been reached.
 119      */
 120     public int read() throws IOException
 121     {
 122         if (bytesLeft > 0) {
 123             int data = in.read();
 124             if (data != -1)
 125                 -- bytesLeft;
 126 
 127             if (RMIMasterSocketFactory.proxyLog.isLoggable(Log.VERBOSE)) {
 128                 RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,
 129                    "received byte: '" +
 130                     ((data & 0x7F) < ' ' ? " " : String.valueOf((char) data)) +
 131                     "' " + data);
 132             }
 133 
 134             return data;
 135         }
 136         else {
 137             RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,
 138                                                 "read past content length");
 139 
 140             return -1;
 141         }
 142     }
 143 
 144     public int read(byte b[], int off, int len) throws IOException
 145     {
 146         if (bytesLeft == 0 && len > 0) {
 147             RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,
 148                                                 "read past content length");
 149 
 150             return -1;
 151         }
 152         if (len > bytesLeft)
 153             len = bytesLeft;
 154         int bytesRead = in.read(b, off, len);
 155         bytesLeft -= bytesRead;
 156 
 157         if (RMIMasterSocketFactory.proxyLog.isLoggable(Log.VERBOSE)) {
 158             RMIMasterSocketFactory.proxyLog.log(Log.VERBOSE,
 159                 "read " + bytesRead + " bytes, " + bytesLeft + " remaining");
 160         }
 161 
 162         return bytesRead;
 163     }
 164 
 165     /**
 166      * Mark the current position in the stream (for future calls to reset).
 167      * Remember where we are within the proper content of the message, so
 168      * that a reset method call can recreate our state properly.
 169      * @param readlimit how many bytes can be read before mark becomes invalid
 170      */
 171     public void mark(int readlimit)
 172     {
 173         in.mark(readlimit);
 174         if (in.markSupported())
 175             bytesLeftAtMark = bytesLeft;
 176     }
 177 
 178     /**
 179      * Repositions the stream to the last marked position.  Make sure to
 180      * adjust our position within the proper content accordingly.
 181      */
 182     public void reset() throws IOException
 183     {
 184         in.reset();
 185         bytesLeft = bytesLeftAtMark;
 186     }
 187 
 188     /**
 189      * Skips bytes of the stream.  Make sure to adjust our
 190      * position within the proper content accordingly.
 191      * @param n number of bytes to be skipped
 192      */
 193     public long skip(long n) throws IOException
 194     {
 195         if (n > bytesLeft)
 196             n = bytesLeft;
 197         long bytesSkipped = in.skip(n);
 198         bytesLeft -= bytesSkipped;
 199         return bytesSkipped;
 200     }
 201 }