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                         chunkRead = 0;
 205                         chunkSize = 0;
 206                         char c = '\0';
 207                         while (offset < size) {
 208                                 c = (char) buffer [offset++];
 209                                 if (c == '\r') {
 210                                         if (sawCR)
 211                                                 ThrowProtocolViolation ("2 CR found");
 212
 213                                         sawCR = true;
 214                                         continue;
 215                                 }
 216
 217                                 if (sawCR && c == '\n')
 218                                         break;
 219
 220                                 if (c == ' ')
 221                                         gotit = true;
 222
 223                                 if (!gotit)
 224                                         saved.Append (c);
 225
 226                                 if (saved.Length > 20)
 227                                         ThrowProtocolViolation ("chunk size too long.");
 228                         }
 229
 230                         if (!sawCR || c != '\n') {
 231                                 if (offset < size)
 232                                         ThrowProtocolViolation ("Missing \\n");
 233
 234                                 try {
 235                                         if (saved.Length > 0) {
 236                                                 chunkSize = Int32.Parse (RemoveChunkExtension (saved.ToString ()), NumberStyles.HexNumber);
 237                                         }
 238                                 } catch (Exception) {
 239                                         ThrowProtocolViolation ("Cannot parse chunk size.");
 240                                 }
 241
 242                                 return State.None;
 243                         }
 244
 245                         chunkRead = 0;
 246                         try {
 247                                 chunkSize = Int32.Parse (RemoveChunkExtension (saved.ToString ()), NumberStyles.HexNumber);
 248                         } catch (Exception) {
 249                                 ThrowProtocolViolation ("Cannot parse chunk size.");
 250                         }
 251
 252                         if (chunkSize == 0) {
 253                                 trailerState = 2;
 254                                 return State.Trailer;
 255                         }
 256
 257                         return State.Body;
 258                 }
 259
 260                 static string RemoveChunkExtension (string input)
 261                 {
 262                         int idx = input.IndexOf (';');
 263                         if (idx == -1)
 264                                 return input;
 265                         return input.Substring (0, idx);
 266                 }
 267
 268                 State ReadCRLF (byte [] buffer, ref int offset, int size)
 269                 {
 270                         if (!sawCR) {
 271                                 if ((char) buffer [offset++] != '\r')
 272                                         ThrowProtocolViolation ("Expecting \\r");
 273
 274                                 sawCR = true;
 275                                 if (offset == size)
 276                                         return State.BodyFinished;
 277                         }
 278
 279                         if (sawCR && (char) buffer [offset++] != '\n')
 280                                 ThrowProtocolViolation ("Expecting \\n");
 281
 282                         return State.None;
 283                 }
 284
 285                 State ReadTrailer (byte [] buffer, ref int offset, int size)
 286                 {
 287                         char c = '\0';
 288
 289                         // short path
 290                         if (trailerState == 2 && (char) buffer [offset] == '\r' && saved.Length == 0) {
 291                                 offset++;
 292                                 if (offset < size && (char) buffer [offset] == '\n') {
 293                                         offset++;
 294                                         return State.None;
 295                                 }
 296                                 offset--;
 297                         }
 298
 299                         int st = trailerState;
 300                         string stString = "\r\n\r";
 301                         while (offset < size && st < 4) {
 302                                 c = (char) buffer [offset++];
 303                                 if ((st == 0 || st == 2) && c == '\r') {
 304                                         st++;
 305                                         continue;
 306                                 }
 307
 308                                 if ((st == 1 || st == 3) && c == '\n') {
 309                                         st++;
 310                                         continue;
 311                                 }
 312
 313                                 if (st > 0) {
 314                                         saved.Append (stString.Substring (0, saved.Length == 0? st-2: st));
 315                                         st = 0;
 316                                         if (saved.Length > 4196)
 317                                                 ThrowProtocolViolation ("Error reading trailer (too long).");
 318                                 }
 319                         }
 320
 321                         if (st < 4) {
 322                                 trailerState = st;
 323                                 if (offset < size)
 324                                         ThrowProtocolViolation ("Error reading trailer.");
 325
 326                                 return State.Trailer;
 327                         }
 328
 329                         StringReader reader = new StringReader (saved.ToString ());
 330                         string line;
 331                         while ((line = reader.ReadLine ()) != null && line != "")
 332                                 headers.Add (line);
 333
 334                         return State.None;
 335                 }
 336
 337                 static void ThrowProtocolViolation (string message)
 338                 {
 339                         WebException we = new WebException (message, null, WebExceptionStatus.ServerProtocolViolation, null);
 340                         throw we;
 341                 }
 342         }
 343 }
 344