mcs/class/System/System.Net/ChunkStream.cs

   1 //
   2 // System.Net.ChunkStream
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //
   7 // (C) 2003 Ximian, Inc (http://www.ximian.com)
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System.Collections;
  32 using System.Globalization;
  33 using System.IO;
  34 using System.Text;
  35
  36 namespace System.Net
  37 {
  38         class ChunkStream
  39         {
  40                 enum State {
  41                         None,
  42                         Body,
  43                         BodyFinished,
  44                         Trailer
  45                 }
  46
  47                 class Chunk {
  48                         public byte [] Bytes;
  49                         public int Offset;
  50
  51                         public Chunk (byte [] chunk)
  52                         {
  53                                 this.Bytes = chunk;
  54                         }
  55
  56                         public int Read (byte [] buffer, int offset, int size)
  57                         {
  58                                 int nread = (size > Bytes.Length - Offset) ? Bytes.Length - Offset : size;
  59                                 Buffer.BlockCopy (Bytes, Offset, buffer, offset, nread);
  60                                 Offset += nread;
  61                                 return nread;
  62                         }
  63                 }
  64
  65                 internal WebHeaderCollection headers;
  66                 int chunkSize;
  67                 int chunkRead;
  68                 State state;
  69                 //byte [] waitBuffer;
  70                 StringBuilder saved;
  71                 bool sawCR;
  72                 bool gotit;
  73                 int trailerState;
  74                 ArrayList chunks;
  75
  76                 public ChunkStream (byte [] buffer, int offset, int size, WebHeaderCollection headers)
  77                                         : this (headers)
  78                 {
  79                         Write (buffer, offset, size);
  80                 }
  81
  82                 public ChunkStream (WebHeaderCollection headers)
  83                 {
  84                         this.headers = headers;
  85                         saved = new StringBuilder ();
  86                         chunks = new ArrayList ();
  87                         chunkSize = -1;
  88                 }
  89
  90                 public void ResetBuffer ()
  91                 {
  92                         chunkSize = -1;
  93                         chunkRead = 0;
  94                         chunks.Clear ();
  95                 }
  96
  97                 public void WriteAndReadBack (byte [] buffer, int offset, int size, ref int read)
  98                 {
  99                         if (offset + read > 0)
 100                                 Write (buffer, offset, offset+read);
 101                         read = Read (buffer, offset, size);
 102                 }
 103
 104                 public int Read (byte [] buffer, int offset, int size)
 105                 {
 106                         return ReadFromChunks (buffer, offset, size);
 107                 }
 108
 109                 int ReadFromChunks (byte [] buffer, int offset, int size)
 110                 {
 111                         int count = chunks.Count;
 112                         int nread = 0;
 113                         for (int i = 0; i < count; i++) {
 114                                 Chunk chunk = (Chunk) chunks [i];
 115                                 if (chunk == null)
 116                                         continue;
 117
 118                                 if (chunk.Offset == chunk.Bytes.Length) {
 119                                         chunks [i] = null;
 120                                         continue;
 121                                 }
 122
 123                                 nread += chunk.Read (buffer, offset + nread, size - nread);
 124                                 if (nread == size)
 125                                         break;
 126                         }
 127
 128                         return nread;
 129                 }
 130
 131                 public void Write (byte [] buffer, int offset, int size)
 132                 {
 133                         InternalWrite (buffer, ref offset, size);
 134                 }
 135
 136                 void InternalWrite (byte [] buffer, ref int offset, int size)
 137                 {
 138                         if (state == State.None) {
 139                                 state = GetChunkSize (buffer, ref offset, size);
 140                                 if (state == State.None)
 141                                         return;
 142
 143                                 saved.Length = 0;
 144                                 sawCR = false;
 145                                 gotit = false;
 146                         }
 147
 148                         if (state == State.Body && offset < size) {
 149                                 state = ReadBody (buffer, ref offset, size);
 150                                 if (state == State.Body)
 151                                         return;
 152                         }
 153
 154                         if (state == State.BodyFinished && offset < size) {
 155                                 state = ReadCRLF (buffer, ref offset, size);
 156                                 if (state == State.BodyFinished)
 157                                         return;
 158
 159                                 sawCR = false;
 160                         }
 161
 162                         if (state == State.Trailer && offset < size) {
 163                                 state = ReadTrailer (buffer, ref offset, size);
 164                                 if (state == State.Trailer)
 165                                         return;
 166
 167                                 saved.Length = 0;
 168                                 sawCR = false;
 169                                 gotit = false;
 170                         }
 171
 172                         if (offset < size)
 173                                 InternalWrite (buffer, ref offset, size);
 174                 }
 175
 176                 public bool WantMore {
 177                         get { return (chunkRead != chunkSize || chunkSize != 0 || state != State.None); }
 178                 }
 179
 180                 public int ChunkLeft {
 181                         get { return chunkSize - chunkRead; }
 182                 }
 183
 184                 State ReadBody (byte [] buffer, ref int offset, int size)
 185                 {
 186                         if (chunkSize == 0)
 187                                 return State.BodyFinished;
 188
 189                         int diff = size - offset;
 190                         if (diff + chunkRead > chunkSize)
 191                                 diff = chunkSize - chunkRead;
 192
 193                         byte [] chunk = new byte [diff];
 194                         Buffer.BlockCopy (buffer, offset, chunk, 0, diff);
 195                         chunks.Add (new Chunk (chunk));
 196                         offset += diff;
 197                         chunkRead += diff;
 198                         return (chunkRead == chunkSize) ? State.BodyFinished : State.Body;
 199
 200                 }
 201
 202                 State GetChunkSize (byte [] buffer, ref int offset, int size)
 203                 {
 204                         char c = '\0';
 205                         while (offset < size) {
 206                                 c = (char) buffer [offset++];
 207                                 if (c == '\r') {
 208                                         if (sawCR)
 209                                                 ThrowProtocolViolation ("2 CR found");
 210
 211                                         sawCR = true;
 212                                         continue;
 213                                 }
 214
 215                                 if (sawCR && c == '\n')
 216                                         break;
 217
 218                                 if (c == ' ')
 219                                         gotit = true;
 220
 221                                 if (!gotit)
 222                                         saved.Append (c);
 223
 224                                 if (saved.Length > 20)
 225                                         ThrowProtocolViolation ("chunk size too long.");
 226                         }
 227
 228                         if (!sawCR || c != '\n') {
 229                                 if (offset < size)
 230                                         ThrowProtocolViolation ("Missing \\n");
 231
 232                                 try {
 233                                         if (saved.Length > 0)
 234                                                 chunkSize = Int32.Parse (saved.ToString (), NumberStyles.HexNumber);
 235                                 } catch (Exception) {
 236                                         ThrowProtocolViolation ("Cannot parse chunk size.");
 237                                 }
 238
 239                                 return State.None;
 240                         }
 241
 242                         chunkRead = 0;
 243                         try {
 244                                 chunkSize = Int32.Parse (saved.ToString (), NumberStyles.HexNumber);
 245                         } catch (Exception) {
 246                                 ThrowProtocolViolation ("Cannot parse chunk size.");
 247                         }
 248
 249                         if (chunkSize == 0) {
 250                                 trailerState = 2;
 251                                 return State.Trailer;
 252                         }
 253
 254                         return State.Body;
 255                 }
 256
 257                 State ReadCRLF (byte [] buffer, ref int offset, int size)
 258                 {
 259                         if (!sawCR) {
 260                                 if ((char) buffer [offset++] != '\r')
 261                                         ThrowProtocolViolation ("Expecting \\r");
 262
 263                                 sawCR = true;
 264                                 if (offset == size)
 265                                         return State.BodyFinished;
 266                         }
 267
 268                         if (sawCR && (char) buffer [offset++] != '\n')
 269                                 ThrowProtocolViolation ("Expecting \\n");
 270
 271                         return State.None;
 272                 }
 273
 274                 State ReadTrailer (byte [] buffer, ref int offset, int size)
 275                 {
 276                         char c = '\0';
 277
 278                         // short path
 279                         if (trailerState == 2 && (char) buffer [offset] == '\r' && saved.Length == 0) {
 280                                 offset++;
 281                                 if (offset < size && (char) buffer [offset] == '\n') {
 282                                         offset++;
 283                                         return State.None;
 284                                 }
 285                                 offset--;
 286                         }
 287
 288                         int st = trailerState;
 289                         string stString = "\r\n\r";
 290                         while (offset < size && st < 4) {
 291                                 c = (char) buffer [offset++];
 292                                 if ((st == 0 || st == 2) && c == '\r') {
 293                                         st++;
 294                                         continue;
 295                                 }
 296
 297                                 if ((st == 1 || st == 3) && c == '\n') {
 298                                         st++;
 299                                         continue;
 300                                 }
 301
 302                                 if (st > 0) {
 303                                         saved.Append (stString.Substring (0, saved.Length == 0? st-2: st));
 304                                         st = 0;
 305                                 }
 306                         }
 307
 308                         if (st < 4) {
 309                                 trailerState = st;
 310                                 if (offset <  size)
 311                                         ThrowProtocolViolation ("Error reading trailer.");
 312
 313                                 return State.Trailer;
 314                         }
 315
 316                         StringReader reader = new StringReader (saved.ToString ());
 317                         string line;
 318                         while ((line = reader.ReadLine ()) != null && line != "")
 319                                 headers.Add (line);
 320
 321                         return State.None;
 322                 }
 323
 324                 static void ThrowProtocolViolation (string message)
 325                 {
 326                         WebException we = new WebException (message, null, WebExceptionStatus.ServerProtocolViolation, null);
 327                         throw we;
 328                 }
 329         }
 330 }
 331