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                 WebHeaderCollection headers;
  66                 int chunkSize;
  67                 int chunkRead;
  68                 State state;
  69                 //byte [] waitBuffer;
  70                 StringBuilder saved;
  71                 bool sawCR;
  72                 bool gotit;
  73                 ArrayList chunks;
  74
  75                 public ChunkStream (byte [] buffer, int offset, int size, WebHeaderCollection headers)
  76                 {
  77                         this.headers = headers;
  78                         saved = new StringBuilder ();
  79                         chunks = new ArrayList ();
  80                         chunkSize = -1;
  81                         Write (buffer, offset, size);
  82                 }
  83
  84                 public void ResetBuffer ()
  85                 {
  86                         chunkSize = -1;
  87                         chunkRead = 0;
  88                         chunks.Clear ();
  89                 }
  90
  91                 public void WriteAndReadBack (byte [] buffer, int offset, int size, ref int read)
  92                 {
  93                         if (offset + read > 0)
  94                                 Write (buffer, offset, offset+read);
  95                         read = Read (buffer, offset, size);
  96                 }
  97
  98                 public int Read (byte [] buffer, int offset, int size)
  99                 {
 100                         return ReadFromChunks (buffer, offset, size);
 101                 }
 102
 103                 int ReadFromChunks (byte [] buffer, int offset, int size)
 104                 {
 105                         int count = chunks.Count;
 106                         int nread = 0;
 107                         for (int i = 0; i < count; i++) {
 108                                 Chunk chunk = (Chunk) chunks [i];
 109                                 if (chunk == null)
 110                                         continue;
 111
 112                                 if (chunk.Offset == chunk.Bytes.Length) {
 113                                         chunks [i] = null;
 114                                         continue;
 115                                 }
 116
 117                                 nread += chunk.Read (buffer, offset + nread, size - nread);
 118                                 if (nread == size)
 119                                         break;
 120                         }
 121
 122                         return nread;
 123                 }
 124
 125                 public void Write (byte [] buffer, int offset, int size)
 126                 {
 127                         InternalWrite (buffer, ref offset, size);
 128                 }
 129
 130                 void InternalWrite (byte [] buffer, ref int offset, int size)
 131                 {
 132                         if (state == State.None) {
 133                                 state = GetChunkSize (buffer, ref offset, size);
 134                                 if (state == State.None)
 135                                         return;
 136
 137                                 saved.Length = 0;
 138                                 sawCR = false;
 139                                 gotit = false;
 140                         }
 141
 142                         if (state == State.Body && offset < size) {
 143                                 state = ReadBody (buffer, ref offset, size);
 144                                 if (state == State.Body)
 145                                         return;
 146                         }
 147
 148                         if (state == State.BodyFinished && offset < size) {
 149                                 state = ReadCRLF (buffer, ref offset, size);
 150                                 if (state == State.BodyFinished)
 151                                         return;
 152
 153                                 sawCR = false;
 154                         }
 155
 156                         if (state == State.Trailer && offset < size) {
 157                                 state = ReadTrailer (buffer, ref offset, size);
 158                                 if (state == State.Trailer)
 159                                         return;
 160
 161                                 saved.Length = 0;
 162                                 sawCR = false;
 163                                 gotit = false;
 164                         }
 165
 166                         if (offset < size)
 167                                 InternalWrite (buffer, ref offset, size);
 168                 }
 169
 170                 public bool WantMore {
 171                         get { return (chunkRead != chunkSize || chunkSize != 0 || state != State.None); }
 172                 }
 173
 174                 public int ChunkLeft {
 175                         get { return chunkSize - chunkRead; }
 176                 }
 177
 178                 State ReadBody (byte [] buffer, ref int offset, int size)
 179                 {
 180                         if (chunkSize == 0)
 181                                 return State.BodyFinished;
 182
 183                         int diff = size - offset;
 184                         if (diff + chunkRead > chunkSize)
 185                                 diff = chunkSize - chunkRead;
 186
 187                         byte [] chunk = new byte [diff];
 188                         Buffer.BlockCopy (buffer, offset, chunk, 0, diff);
 189                         chunks.Add (new Chunk (chunk));
 190                         offset += diff;
 191                         chunkRead += diff;
 192                         return (chunkRead == chunkSize) ? State.BodyFinished : State.Body;
 193
 194                 }
 195
 196                 State GetChunkSize (byte [] buffer, ref int offset, int size)
 197                 {
 198                         char c = '\0';
 199                         while (offset < size) {
 200                                 c = (char) buffer [offset++];
 201                                 if (c == '\r') {
 202                                         if (sawCR)
 203                                                 ThrowProtocolViolation ("2 CR found");
 204
 205                                         sawCR = true;
 206                                         continue;
 207                                 }
 208
 209                                 if (sawCR && c == '\n')
 210                                         break;
 211
 212                                 if (c == ' ')
 213                                         gotit = true;
 214
 215                                 if (!gotit)
 216                                         saved.Append (c);
 217
 218                                 if (saved.Length > 20)
 219                                         ThrowProtocolViolation ("chunk size too long.");
 220                         }
 221
 222                         if (!sawCR || c != '\n') {
 223                                 if (offset < size)
 224                                         ThrowProtocolViolation ("Missing \\n");
 225
 226                                 try {
 227                                         if (saved.Length > 0)
 228                                                 chunkSize = Int32.Parse (saved.ToString (), NumberStyles.HexNumber);
 229                                 } catch (Exception) {
 230                                         ThrowProtocolViolation ("Cannot parse chunk size.");
 231                                 }
 232
 233                                 return State.None;
 234                         }
 235
 236                         chunkRead = 0;
 237                         try {
 238                                 chunkSize = Int32.Parse (saved.ToString (), NumberStyles.HexNumber);
 239                         } catch (Exception) {
 240                                 ThrowProtocolViolation ("Cannot parse chunk size.");
 241                         }
 242
 243                         if (chunkSize == 0)
 244                                 return State.Trailer;
 245
 246                         return State.Body;
 247                 }
 248
 249                 State ReadCRLF (byte [] buffer, ref int offset, int size)
 250                 {
 251                         if (!sawCR) {
 252                                 if ((char) buffer [offset++] != '\r')
 253                                         ThrowProtocolViolation ("Expecting \\r");
 254
 255                                 sawCR = true;
 256                                 if (offset == size)
 257                                         return State.BodyFinished;
 258                         }
 259
 260                         if (sawCR && (char) buffer [offset++] != '\n')
 261                                 ThrowProtocolViolation ("Expecting \\n");
 262
 263                         return State.None;
 264                 }
 265
 266                 State ReadTrailer (byte [] buffer, ref int offset, int size)
 267                 {
 268                         char c = '\0';
 269
 270                         // short path
 271                         if ((char) buffer [offset] == '\r') {
 272                                 offset++;
 273                                 if ((char) buffer [offset] == '\n') {
 274                                         offset++;
 275                                         return State.None;
 276                                 }
 277                                 offset--;
 278                         }
 279
 280                         int st = 0;
 281                         string stString = "\r\n\r";
 282                         while (offset < size && st < 4) {
 283                                 c = (char) buffer [offset++];
 284                                 if ((st == 0 || st == 2) && c == '\r') {
 285                                         st++;
 286                                         continue;
 287                                 }
 288
 289                                 if ((st == 1 || st == 3) && c == '\n') {
 290                                         st++;
 291                                         continue;
 292                                 }
 293
 294                                 if (st > 0) {
 295                                         saved.Append (stString.Substring (0, st));
 296                                         st = 0;
 297                                 }
 298                         }
 299
 300                         if (st < 4) {
 301                                 if (offset <  size)
 302                                         ThrowProtocolViolation ("Error reading trailer.");
 303
 304                                 return State.Trailer;
 305                         }
 306
 307                         StringReader reader = new StringReader (saved.ToString ());
 308                         string line;
 309                         while ((line = reader.ReadLine ()) != null && line != "")
 310                                 headers.Add (line);
 311
 312                         return State.None;
 313                 }
 314
 315                 static void ThrowProtocolViolation (string message)
 316                 {
 317                         WebException we = new WebException (message, null, WebExceptionStatus.ServerProtocolViolation, null);
 318                         throw we;
 319                 }
 320         }
 321 }
 322