net/http/http_chunked_decoder.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // Derived from:
   6 //   mozilla/netwerk/protocol/http/src/nsHttpChunkedDecoder.h
   7 // The license block is:
   8 /* ***** BEGIN LICENSE BLOCK *****
   9  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  10  *
  11  * The contents of this file are subject to the Mozilla Public License Version
  12  * 1.1 (the "License"); you may not use this file except in compliance with
  13  * the License. You may obtain a copy of the License at
  14  * http://www.mozilla.org/MPL/
  15  *
  16  * Software distributed under the License is distributed on an "AS IS" basis,
  17  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  18  * for the specific language governing rights and limitations under the
  19  * License.
  20  *
  21  * The Original Code is Mozilla.
  22  *
  23  * The Initial Developer of the Original Code is
  24  * Netscape Communications.
  25  * Portions created by the Initial Developer are Copyright (C) 2001
  26  * the Initial Developer. All Rights Reserved.
  27  *
  28  * Contributor(s):
  29  *   Darin Fisher <darin@netscape.com> (original author)
  30  *
  31  * Alternatively, the contents of this file may be used under the terms of
  32  * either the GNU General Public License Version 2 or later (the "GPL"), or
  33  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  34  * in which case the provisions of the GPL or the LGPL are applicable instead
  35  * of those above. If you wish to allow use of your version of this file only
  36  * under the terms of either the GPL or the LGPL, and not to allow others to
  37  * use your version of this file under the terms of the MPL, indicate your
  38  * decision by deleting the provisions above and replace them with the notice
  39  * and other provisions required by the GPL or the LGPL. If you do not delete
  40  * the provisions above, a recipient may use your version of this file under
  41  * the terms of any one of the MPL, the GPL or the LGPL.
  42  *
  43  * ***** END LICENSE BLOCK ***** */
  44
  45 #ifndef NET_HTTP_HTTP_CHUNKED_DECODER_H_
  46 #define NET_HTTP_HTTP_CHUNKED_DECODER_H_
  47
  48 #include <string>
  49
  50 #include "net/base/net_export.h"
  51
  52 namespace net {
  53
  54 // From RFC2617 section 3.6.1, the chunked transfer coding is defined as:
  55 //
  56 //   Chunked-Body    = *chunk
  57 //                     last-chunk
  58 //                     trailer
  59 //                     CRLF
  60 //   chunk           = chunk-size [ chunk-extension ] CRLF
  61 //                     chunk-data CRLF
  62 //   chunk-size      = 1*HEX
  63 //   last-chunk      = 1*("0") [ chunk-extension ] CRLF
  64 //
  65 //   chunk-extension = *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
  66 //   chunk-ext-name  = token
  67 //   chunk-ext-val   = token | quoted-string
  68 //   chunk-data      = chunk-size(OCTET)
  69 //   trailer         = *(entity-header CRLF)
  70 //
  71 // The chunk-size field is a string of hex digits indicating the size of the
  72 // chunk.  The chunked encoding is ended by any chunk whose size is zero,
  73 // followed by the trailer, which is terminated by an empty line.
  74 //
  75 // NOTE: This implementation does not bother to parse trailers since they are
  76 // not used on the web.
  77 //
  78 class NET_EXPORT_PRIVATE HttpChunkedDecoder {
  79  public:
  80   // The maximum length of |line_buf_| between calls to FilterBuff().
  81   // Exposed for tests.
  82   static const size_t kMaxLineBufLen;
  83
  84   HttpChunkedDecoder();
  85
  86   // Indicates that a previous call to FilterBuf encountered the final CRLF.
  87   bool reached_eof() const { return reached_eof_; }
  88
  89   // Returns the number of bytes after the final CRLF.
  90   int bytes_after_eof() const { return bytes_after_eof_; }
  91
  92   // Called to filter out the chunk markers from buf and to check for end-of-
  93   // file.  This method modifies |buf| inline if necessary to remove chunk
  94   // markers.  The return value indicates the final size of decoded data stored
  95   // in |buf|.  Call reached_eof() after this method to check if end-of-file
  96   // was encountered.
  97   int FilterBuf(char* buf, int buf_len);
  98
  99  private:
 100   // Scans |buf| for the next chunk delimiter.  This method returns the number
 101   // of bytes consumed from |buf|.  If found, |chunk_remaining_| holds the
 102   // value for the next chunk size.
 103   int ScanForChunkRemaining(const char* buf, int buf_len);
 104
 105   // Converts string |start| of length |len| to a numeric value.
 106   // |start| is a string of type "chunk-size" (hex string).
 107   // If the conversion succeeds, returns true and places the result in |out|.
 108   static bool ParseChunkSize(const char* start, int len, int* out);
 109
 110   // Indicates the number of bytes remaining for the current chunk.
 111   int chunk_remaining_;
 112
 113   // A small buffer used to store a partial chunk marker.
 114   std::string line_buf_;
 115
 116   // True if waiting for the terminal CRLF of a chunk's data.
 117   bool chunk_terminator_remaining_;
 118
 119   // Set to true when FilterBuf encounters the last-chunk.
 120   bool reached_last_chunk_;
 121
 122   // Set to true when FilterBuf encounters the final CRLF.
 123   bool reached_eof_;
 124
 125   // The number of extraneous unfiltered bytes after the final CRLF.
 126   int bytes_after_eof_;
 127 };
 128
 129 }  // namespace net
 130
 131 #endif  // NET_HTTP_HTTP_CHUNKED_DECODER_H_