1 // Copyright 2011 The Chromium Authors 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 <stddef.h> 49 #include <stdint.h> 50 51 #include <string> 52 53 #include "base/containers/span.h" 54 #include "net/base/net_export.h" 55 56 namespace net { 57 58 // From RFC2617 section 3.6.1, the chunked transfer coding is defined as: 59 // 60 // Chunked-Body = *chunk 61 // last-chunk 62 // trailer 63 // CRLF 64 // chunk = chunk-size [ chunk-extension ] CRLF 65 // chunk-data CRLF 66 // chunk-size = 1*HEX 67 // last-chunk = 1*("0") [ chunk-extension ] CRLF 68 // 69 // chunk-extension = *( ";" chunk-ext-name [ "=" chunk-ext-val ] ) 70 // chunk-ext-name = token 71 // chunk-ext-val = token | quoted-string 72 // chunk-data = chunk-size(OCTET) 73 // trailer = *(entity-header CRLF) 74 // 75 // The chunk-size field is a string of hex digits indicating the size of the 76 // chunk. The chunked encoding is ended by any chunk whose size is zero, 77 // followed by the trailer, which is terminated by an empty line. 78 // 79 // NOTE: This implementation does not bother to parse trailers since they are 80 // not used on the web. 81 // 82 class NET_EXPORT_PRIVATE HttpChunkedDecoder { 83 public: 84 // The maximum length of |line_buf_| between calls to FilterBuff(). 85 // Exposed for tests. 86 static const size_t kMaxLineBufLen; 87 88 HttpChunkedDecoder(); 89 90 // Indicates that a previous call to FilterBuf encountered the final CRLF. reached_eof()91 bool reached_eof() const { return reached_eof_; } 92 93 // Returns the number of bytes after the final CRLF. bytes_after_eof()94 int bytes_after_eof() const { return bytes_after_eof_; } 95 96 // Called to filter out the chunk markers from buf and to check for end-of- 97 // file. This method modifies |buf| inline if necessary to remove chunk 98 // markers. The return value indicates the final size of decoded data stored 99 // in |buf|. Call reached_eof() after this method to check if end-of-file 100 // was encountered. 101 int FilterBuf(base::span<uint8_t> buf); 102 103 private: 104 // Scans |buf| for the next chunk delimiter. This method returns the number 105 // of bytes consumed from |buf|. If found, |chunk_remaining_| holds the 106 // value for the next chunk size. 107 int ScanForChunkRemaining(base::span<const uint8_t> buf); 108 109 // Converts the buffer |buf| to a numeric value. 110 // |buf| is a buffer containing a "chunk-size" (hex string). 111 // If the conversion succeeds, returns true and places the result in |out|. 112 static bool ParseChunkSize(base::span<const uint8_t> buf, uint64_t* out); 113 114 // Indicates the number of bytes remaining for the current chunk. 115 // Using uint64_t as it can exceed size_t. 116 uint64_t chunk_remaining_ = 0; 117 118 // A small buffer used to store a partial chunk marker. 119 std::string line_buf_; 120 121 // True if waiting for the terminal CRLF of a chunk's data. 122 bool chunk_terminator_remaining_ = false; 123 124 // Set to true when FilterBuf encounters the last-chunk. 125 bool reached_last_chunk_ = false; 126 127 // Set to true when FilterBuf encounters the final CRLF. 128 bool reached_eof_ = false; 129 130 // The number of extraneous unfiltered bytes after the final CRLF. 131 int bytes_after_eof_ = 0; 132 }; 133 134 } // namespace net 135 136 #endif // NET_HTTP_HTTP_CHUNKED_DECODER_H_ 137