mcs/class/corlib/System.IO/StreamWriter.cs

   1 //\r
   2 // System.IO.StreamWriter.cs\r
   3 //\r
   4 // Authors:\r
   5 //   Dietmar Maurer (dietmar@ximian.com)\r
   6 //   Paolo Molaro (lupus@ximian.com)\r
   7 //   Marek Safar (marek.safar@gmail.com)\r
   8 //\r
   9 // (C) Ximian, Inc.  http://www.ximian.com\r
  10 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)\r
  11 // Copyright 2011, 2013 Xamarin Inc.\r
  12 //\r
  13 // Permission is hereby granted, free of charge, to any person obtaining\r
  14 // a copy of this software and associated documentation files (the\r
  15 // "Software"), to deal in the Software without restriction, including\r
  16 // without limitation the rights to use, copy, modify, merge, publish,\r
  17 // distribute, sublicense, and/or sell copies of the Software, and to\r
  18 // permit persons to whom the Software is furnished to do so, subject to\r
  19 // the following conditions:\r
  20 // \r
  21 // The above copyright notice and this permission notice shall be\r
  22 // included in all copies or substantial portions of the Software.\r
  23 // \r
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,\r
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF\r
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND\r
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE\r
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION\r
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION\r
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\r
  31 //\r
  32 \r
  33 using System.Text;\r
  34 using System.Runtime.InteropServices;\r
  35 #if NET_4_5\r
  36 using System.Threading.Tasks;\r
  37 #endif\r
  38 \r
  39 namespace System.IO {\r
  40         \r
  41         [Serializable]\r
  42         [ComVisible (true)]\r
  43         public class StreamWriter : TextWriter {\r
  44 \r
  45                 private Encoding internalEncoding;\r
  46 \r
  47                 private Stream internalStream;\r
  48 \r
  49                 private const int DefaultBufferSize = 1024;\r
  50                 private const int DefaultFileBufferSize = 4096;\r
  51                 private const int MinimumBufferSize = 256;\r
  52 \r
  53                 private byte[] byte_buf;\r
  54                 private char[] decode_buf;\r
  55                 private int byte_pos;\r
  56                 private int decode_pos;\r
  57 \r
  58                 private bool iflush;\r
  59                 private bool preamble_done;\r
  60 \r
  61 #if NET_4_5\r
  62                 readonly bool leave_open;\r
  63                 IDecoupledTask async_task;\r
  64 #endif\r
  65 \r
  66                 public new static readonly StreamWriter Null = new StreamWriter (Stream.Null, Encoding.UTF8Unmarked, 1);\r
  67 \r
  68                 public StreamWriter (Stream stream)\r
  69                         : this (stream, Encoding.UTF8Unmarked, DefaultBufferSize) {}\r
  70 \r
  71                 public StreamWriter (Stream stream, Encoding encoding)\r
  72                         : this (stream, encoding, DefaultBufferSize) {}\r
  73 \r
  74                 internal void Initialize(Encoding encoding, int bufferSize) {\r
  75                         internalEncoding = encoding;\r
  76                         decode_pos = byte_pos = 0;\r
  77                         int BufferSize = Math.Max(bufferSize, MinimumBufferSize);\r
  78                         decode_buf = new char [BufferSize];\r
  79                         byte_buf = new byte [encoding.GetMaxByteCount (BufferSize)];\r
  80 \r
  81                         // Fixes bug http://bugzilla.ximian.com/show_bug.cgi?id=74513\r
  82                         if (internalStream.CanSeek && internalStream.Position > 0)\r
  83                                 preamble_done = true;\r
  84                 }\r
  85 \r
  86 #if NET_4_5\r
  87                 public StreamWriter (Stream stream, Encoding encoding, int bufferSize)\r
  88                         : this (stream, encoding, bufferSize, false)\r
  89                 {\r
  90                 }\r
  91                 \r
  92                 public StreamWriter (Stream stream, Encoding encoding, int bufferSize, bool leaveOpen)\r
  93 #else\r
  94                 const bool leave_open = false;\r
  95 \r
  96                 public StreamWriter (Stream stream, Encoding encoding, int bufferSize)\r
  97 #endif\r
  98                 {\r
  99                         if (null == stream)\r
 100                                 throw new ArgumentNullException("stream");\r
 101                         if (null == encoding)\r
 102                                 throw new ArgumentNullException("encoding");\r
 103                         if (bufferSize <= 0)\r
 104                                 throw new ArgumentOutOfRangeException("bufferSize");\r
 105                         if (!stream.CanWrite)\r
 106                                 throw new ArgumentException ("Can not write to stream");\r
 107 \r
 108 #if NET_4_5\r
 109                         leave_open = leaveOpen;\r
 110 #endif\r
 111                         internalStream = stream;\r
 112 \r
 113                         Initialize(encoding, bufferSize);\r
 114                 }\r
 115 \r
 116                 public StreamWriter (string path)\r
 117                         : this (path, false, Encoding.UTF8Unmarked, DefaultFileBufferSize) {}\r
 118 \r
 119                 public StreamWriter (string path, bool append)\r
 120                         : this (path, append, Encoding.UTF8Unmarked, DefaultFileBufferSize) {}\r
 121 \r
 122                 public StreamWriter (string path, bool append, Encoding encoding)\r
 123                         : this (path, append, encoding, DefaultFileBufferSize) {}\r
 124 \r
 125                 public StreamWriter (string path, bool append, Encoding encoding, int bufferSize)\r
 126                 {\r
 127                         if (null == encoding)\r
 128                                 throw new ArgumentNullException("encoding");\r
 129                         if (bufferSize <= 0)\r
 130                                 throw new ArgumentOutOfRangeException("bufferSize");\r
 131 \r
 132                         FileMode mode;\r
 133 \r
 134                         if (append)\r
 135                                 mode = FileMode.Append;\r
 136                         else\r
 137                                 mode = FileMode.Create;\r
 138                         \r
 139                         internalStream = new FileStream (path, mode, FileAccess.Write, FileShare.Read);\r
 140 \r
 141                         if (append)\r
 142                                 internalStream.Position = internalStream.Length;\r
 143                         else\r
 144                                 internalStream.SetLength (0);\r
 145 \r
 146                         Initialize(encoding, bufferSize);\r
 147                 }\r
 148 \r
 149                 public virtual bool AutoFlush {\r
 150                         get {\r
 151                                 return iflush;\r
 152                         }\r
 153                         set {\r
 154                                 iflush = value;\r
 155                                 if (iflush)\r
 156                                         Flush ();\r
 157                         }\r
 158                 }\r
 159 \r
 160                 public virtual Stream BaseStream {\r
 161                         get {\r
 162                                 return internalStream;\r
 163                         }\r
 164                 }\r
 165 \r
 166                 public override Encoding Encoding {\r
 167                         get {\r
 168                                 return internalEncoding;\r
 169                         }\r
 170                 }\r
 171 \r
 172                 protected override void Dispose (bool disposing) \r
 173                 {\r
 174                         if (byte_buf == null || !disposing)\r
 175                                 return;\r
 176 \r
 177                         try {\r
 178                                 Flush ();\r
 179                         } finally {\r
 180                                 byte_buf = null;\r
 181                                 internalEncoding = null;\r
 182                                 decode_buf = null;\r
 183 \r
 184                                 if (!leave_open) {\r
 185                                         internalStream.Close ();\r
 186                                 }\r
 187 \r
 188                                 internalStream = null;\r
 189                         }\r
 190                 }\r
 191 \r
 192                 public override void Flush ()\r
 193                 {\r
 194                         CheckState ();\r
 195                         FlushCore ();\r
 196                 }\r
 197 \r
 198                 // Keep in sync with FlushCoreAsync\r
 199                 void FlushCore ()\r
 200                 {\r
 201                         Decode ();\r
 202                         if (byte_pos > 0) {\r
 203                                 FlushBytes ();\r
 204                                 internalStream.Flush ();\r
 205                         }\r
 206                 }\r
 207 \r
 208                 // how the speedup works:\r
 209                 // the Write () methods simply copy the characters in a buffer of chars (decode_buf)\r
 210                 // Decode () is called when the buffer is full or we need to flash.\r
 211                 // Decode () will use the encoding to get the bytes and but them inside\r
 212                 // byte_buf. From byte_buf the data is finally outputted to the stream.\r
 213                 void FlushBytes () \r
 214                 {\r
 215                         // write the encoding preamble only at the start of the stream\r
 216                         if (!preamble_done && byte_pos > 0) {\r
 217                                 byte[] preamble = internalEncoding.GetPreamble ();\r
 218                                 if (preamble.Length > 0)\r
 219                                         internalStream.Write (preamble, 0, preamble.Length);\r
 220                                 preamble_done = true;\r
 221                         }\r
 222                         internalStream.Write (byte_buf, 0, byte_pos);\r
 223                         byte_pos = 0;\r
 224                 }\r
 225 \r
 226                 void Decode () \r
 227                 {\r
 228                         if (byte_pos > 0)\r
 229                                 FlushBytes ();\r
 230                         if (decode_pos > 0) {\r
 231                                 int len = internalEncoding.GetBytes (decode_buf, 0, decode_pos, byte_buf, byte_pos);\r
 232                                 byte_pos += len;\r
 233                                 decode_pos = 0;\r
 234                         }\r
 235                 }\r
 236 \r
 237 #if NET_4_5\r
 238                 async Task FlushCoreAsync ()\r
 239                 {\r
 240                         await DecodeAsync ().ConfigureAwait (false);\r
 241                         if (byte_pos > 0) {\r
 242                                 await FlushBytesAsync ().ConfigureAwait (false);\r
 243                                 await internalStream.FlushAsync ().ConfigureAwait (false);\r
 244                         }\r
 245                 }\r
 246 \r
 247                 async Task FlushBytesAsync ()\r
 248                 {\r
 249                         // write the encoding preamble only at the start of the stream\r
 250                         if (!preamble_done && byte_pos > 0) {\r
 251                                 byte[] preamble = internalEncoding.GetPreamble ();\r
 252                                 if (preamble.Length > 0)\r
 253                                         await internalStream.WriteAsync (preamble, 0, preamble.Length).ConfigureAwait (false);\r
 254                                 preamble_done = true;\r
 255                         }\r
 256 \r
 257                         await internalStream.WriteAsync (byte_buf, 0, byte_pos).ConfigureAwait (false);\r
 258                         byte_pos = 0;\r
 259                 }\r
 260 \r
 261                 async Task DecodeAsync () \r
 262                 {\r
 263                         if (byte_pos > 0)\r
 264                                 await FlushBytesAsync ().ConfigureAwait (false);\r
 265                         if (decode_pos > 0) {\r
 266                                 int len = internalEncoding.GetBytes (decode_buf, 0, decode_pos, byte_buf, byte_pos);\r
 267                                 byte_pos += len;\r
 268                                 decode_pos = 0;\r
 269                         }\r
 270                 }               \r
 271 #endif\r
 272 \r
 273                 public override void Write (char[] buffer, int index, int count) \r
 274                 {\r
 275                         if (buffer == null)\r
 276                                 throw new ArgumentNullException ("buffer");\r
 277                         if (index < 0)\r
 278                                 throw new ArgumentOutOfRangeException ("index", "< 0");\r
 279                         if (count < 0)\r
 280                                 throw new ArgumentOutOfRangeException ("count", "< 0");\r
 281                         // re-ordered to avoid possible integer overflow\r
 282                         if (index > buffer.Length - count)\r
 283                                 throw new ArgumentException ("index + count > buffer.Length");\r
 284 \r
 285                         CheckState ();\r
 286 \r
 287                         LowLevelWrite (buffer, index, count);\r
 288                         if (iflush)\r
 289                                 FlushCore ();\r
 290                 }\r
 291                 \r
 292                 void LowLevelWrite (char[] buffer, int index, int count)\r
 293                 {\r
 294                         while (count > 0) {\r
 295                                 int todo = decode_buf.Length - decode_pos;\r
 296                                 if (todo == 0) {\r
 297                                         Decode ();\r
 298                                         todo = decode_buf.Length;\r
 299                                 }\r
 300                                 if (todo > count)\r
 301                                         todo = count;\r
 302                                 Buffer.BlockCopy (buffer, index * 2, decode_buf, decode_pos * 2, todo * 2);\r
 303                                 count -= todo;\r
 304                                 index += todo;\r
 305                                 decode_pos += todo;\r
 306                         }\r
 307                 }\r
 308                 \r
 309                 void LowLevelWrite (string s)\r
 310                 {\r
 311                         int count = s.Length;\r
 312                         int index = 0;\r
 313                         while (count > 0) {\r
 314                                 int todo = decode_buf.Length - decode_pos;\r
 315                                 if (todo == 0) {\r
 316                                         Decode ();\r
 317                                         todo = decode_buf.Length;\r
 318                                 }\r
 319                                 if (todo > count)\r
 320                                         todo = count;\r
 321                                 \r
 322                                 for (int i = 0; i < todo; i ++)\r
 323                                         decode_buf [i + decode_pos] = s [i + index];\r
 324                                 \r
 325                                 count -= todo;\r
 326                                 index += todo;\r
 327                                 decode_pos += todo;\r
 328                         }\r
 329                 }\r
 330 \r
 331                 public override void Write (char value)\r
 332                 {\r
 333                         CheckState ();\r
 334 \r
 335                         // the size of decode_buf is always > 0 and\r
 336                         // we check for overflow right away\r
 337                         if (decode_pos >= decode_buf.Length)\r
 338                                 Decode ();\r
 339                         decode_buf [decode_pos++] = value;\r
 340                         if (iflush)\r
 341                                 FlushCore ();\r
 342                 }\r
 343 \r
 344                 public override void Write (char[] buffer)\r
 345                 {\r
 346                         CheckState ();\r
 347 \r
 348                         if (buffer != null)\r
 349                                 LowLevelWrite (buffer, 0, buffer.Length);\r
 350                         if (iflush)\r
 351                                 FlushCore ();\r
 352                 }\r
 353 \r
 354                 public override void Write (string value) \r
 355                 {\r
 356                         CheckState ();\r
 357 \r
 358                         if (value != null)\r
 359                                 LowLevelWrite (value);\r
 360                         \r
 361                         if (iflush)\r
 362                                 FlushCore ();\r
 363                 }\r
 364 \r
 365                 public override void Close()\r
 366                 {\r
 367                         Dispose (true);\r
 368                 }\r
 369 \r
 370                 void CheckState ()\r
 371                 {\r
 372                         if (byte_buf == null)\r
 373                                 throw new ObjectDisposedException ("StreamWriter");\r
 374 \r
 375 #if NET_4_5\r
 376                         if (async_task != null && !async_task.IsCompleted)\r
 377                                 throw new InvalidOperationException ();\r
 378 #endif\r
 379                 }\r
 380 \r
 381 #if NET_4_5\r
 382                 public override Task FlushAsync ()\r
 383                 {\r
 384                         CheckState ();\r
 385                         DecoupledTask res;\r
 386                         async_task = res = new DecoupledTask (FlushCoreAsync ());\r
 387                         return res.Task;\r
 388                 }\r
 389 \r
 390                 public override Task WriteAsync (char value)\r
 391                 {\r
 392                         CheckState ();\r
 393 \r
 394                         DecoupledTask res;\r
 395                         async_task = res = new DecoupledTask (WriteAsyncCore (value));\r
 396                         return res.Task;\r
 397                 }\r
 398 \r
 399                 async Task WriteAsyncCore (char value)\r
 400                 {\r
 401                         // the size of decode_buf is always > 0 and\r
 402                         // we check for overflow right away\r
 403                         if (decode_pos >= decode_buf.Length)\r
 404                                 await DecodeAsync ().ConfigureAwait (false);\r
 405                         decode_buf [decode_pos++] = value;\r
 406 \r
 407                         if (iflush)\r
 408                                 await FlushCoreAsync ().ConfigureAwait (false);\r
 409                 }\r
 410 \r
 411                 public override Task WriteAsync (char[] buffer, int index, int count)\r
 412                 {\r
 413                         CheckState ();\r
 414                         if (buffer == null)\r
 415                                 return TaskConstants.Finished;\r
 416 \r
 417                         DecoupledTask res;\r
 418                         async_task = res = new DecoupledTask (WriteAsyncCore (buffer, index, count));\r
 419                         return res.Task;\r
 420                 }\r
 421 \r
 422                 async Task WriteAsyncCore (char[] buffer, int index, int count)\r
 423                 {\r
 424                         // Debug.Assert (buffer == null);\r
 425 \r
 426                         LowLevelWrite (buffer, 0, buffer.Length);\r
 427 \r
 428                         if (iflush)\r
 429                                 await FlushCoreAsync ().ConfigureAwait (false);\r
 430                 }\r
 431 \r
 432                 public override Task WriteAsync (string value)\r
 433                 {\r
 434                         CheckState ();\r
 435                         DecoupledTask res;                      \r
 436                         async_task = res = new DecoupledTask(base.WriteAsync (value));\r
 437                         return res.Task;\r
 438                 }\r
 439 \r
 440                 public override Task WriteLineAsync ()\r
 441                 {\r
 442                         CheckState ();\r
 443                         DecoupledTask res;                      \r
 444                         async_task = res = new DecoupledTask (base.WriteLineAsync ());\r
 445                         return res.Task;\r
 446                 }\r
 447 \r
 448                 public override Task WriteLineAsync (char value)\r
 449                 {\r
 450                         CheckState ();\r
 451                         DecoupledTask res;\r
 452                         async_task = res = new DecoupledTask (base.WriteLineAsync (value));\r
 453                         return res.Task;\r
 454                 }\r
 455 \r
 456                 public override Task WriteLineAsync (char[] buffer, int index, int count)\r
 457                 {\r
 458                         CheckState ();\r
 459                         DecoupledTask res;\r
 460                         async_task = res = new DecoupledTask (base.WriteLineAsync (buffer, index, count));\r
 461                         return res.Task;\r
 462                 }\r
 463 \r
 464                 public override Task WriteLineAsync (string value)\r
 465                 {\r
 466                         CheckState ();\r
 467                         DecoupledTask res;                      \r
 468                         async_task = res = new DecoupledTask (base.WriteLineAsync (value));\r
 469                         return res.Task;\r
 470                 }\r
 471 #endif\r
 472         }\r
 473 }\r