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

   1 //
   2 // System.IO/FileStream.cs
   3 //
   4 // Authors:
   5 //      Dietmar Maurer (dietmar@ximian.com)
   6 //      Dan Lewis (dihlewis@yahoo.co.uk)
   7 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   8 //
   9 // (C) 2001-2003 Ximian, Inc.  http://www.ximian.com
  10 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System.Collections;
  33 using System.Globalization;
  34 using System.Runtime.CompilerServices;
  35 using System.Runtime.InteropServices;
  36 using System.Runtime.Remoting.Messaging;
  37 using System.Security.Permissions;
  38 using System.Threading;
  39
  40 #if NET_2_0
  41 using Microsoft.Win32.SafeHandles;
  42 #endif
  43
  44 namespace System.IO
  45 {
  46         public class FileStream : Stream
  47         {
  48                 // construct from handle
  49
  50                 public FileStream (IntPtr handle, FileAccess access)
  51                         : this (handle, access, true, DefaultBufferSize, false) {}
  52
  53                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle)
  54                         : this (handle, access, ownsHandle, DefaultBufferSize, false) {}
  55
  56                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize)
  57                         : this (handle, access, ownsHandle, bufferSize, false) {}
  58
  59                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync)
  60                         : this (handle, access, ownsHandle, bufferSize, isAsync, false) {}
  61
  62                 [SecurityPermission (SecurityAction.Demand, UnmanagedCode = true)]
  63                 internal FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync, bool noBuffering)
  64                 {
  65                         this.handle = MonoIO.InvalidHandle;
  66                         if (handle == this.handle)
  67                                 throw new ArgumentException ("handle", Locale.GetText ("Invalid."));
  68
  69                         if (access < FileAccess.Read || access > FileAccess.ReadWrite)
  70                                 throw new ArgumentOutOfRangeException ("access");
  71
  72                         MonoIOError error;
  73                         MonoFileType ftype = MonoIO.GetFileType (handle, out error);
  74
  75                         if (error != MonoIOError.ERROR_SUCCESS) {
  76                                 throw MonoIO.GetException (name, error);
  77                         }
  78
  79                         if (ftype == MonoFileType.Unknown) {
  80                                 throw new IOException ("Invalid handle.");
  81                         } else if (ftype == MonoFileType.Disk) {
  82                                 this.canseek = true;
  83                         } else {
  84                                 this.canseek = false;
  85                                 noBuffering = true;
  86                                 bufferSize = 0;
  87                         }
  88
  89                         this.handle = handle;
  90                         this.access = access;
  91                         this.owner = ownsHandle;
  92                         this.async = isAsync;
  93                         this.anonymous = false;
  94
  95                         InitBuffer (bufferSize, noBuffering);
  96
  97                         if (canseek) {
  98                                 buf_start = MonoIO.Seek (handle, 0, SeekOrigin.Current, out error);
  99                                 if (error != MonoIOError.ERROR_SUCCESS) {
 100                                         throw MonoIO.GetException (name, error);
 101                                 }
 102                         }
 103
 104                         /* Can't set append mode */
 105                         this.append_startpos=0;
 106                 }
 107
 108                 // construct from filename
 109
 110                 public FileStream (string name, FileMode mode)
 111                         : this (name, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), FileShare.Read, DefaultBufferSize, false, FileOptions.None)
 112                 {
 113                 }
 114
 115                 public FileStream (string name, FileMode mode, FileAccess access)
 116                         : this (name, mode, access, access == FileAccess.Write ? FileShare.None : FileShare.Read, DefaultBufferSize, false, false)
 117                 {
 118                 }
 119
 120                 public FileStream (string name, FileMode mode, FileAccess access, FileShare share)
 121                         : this (name, mode, access, share, DefaultBufferSize, false, FileOptions.None)
 122                 {
 123                 }
 124
 125                 public FileStream (string name, FileMode mode, FileAccess access, FileShare share, int bufferSize)
 126                         : this (name, mode, access, share, bufferSize, false, FileOptions.None)
 127                 {
 128                 }
 129
 130                 public FileStream (string name, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool isAsync)
 131                         : this (name, mode, access, share, bufferSize, isAsync, FileOptions.None)
 132                 {
 133                 }
 134
 135 #if NET_2_0
 136                 public FileStream (string name, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options)
 137                         : this (name, mode, access, share, bufferSize, false, options)
 138                 {
 139                 }
 140 #endif
 141
 142                 internal FileStream (string name, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool isAsync, bool anonymous)
 143                         : this (name, mode, access, share, bufferSize, anonymous, isAsync ? FileOptions.Asynchronous : FileOptions.None)
 144                 {
 145                 }
 146
 147                 internal FileStream (string name, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool anonymous, FileOptions options)
 148                 {
 149                         if (name == null) {
 150                                 throw new ArgumentNullException ("name");
 151                         }
 152
 153                         if (name.Length == 0) {
 154                                 throw new ArgumentException ("Name is empty");
 155                         }
 156
 157 #if NET_2_0
 158                         // ignore the Inheritable flag
 159                         share &= ~FileShare.Inheritable;
 160
 161 #endif
 162
 163                         if (bufferSize <= 0)
 164                                 throw new ArgumentOutOfRangeException ("Positive number required.");
 165
 166                         if (mode < FileMode.CreateNew || mode > FileMode.Append)
 167                                 throw new ArgumentOutOfRangeException ("mode", "Enum value was out of legal range.");
 168
 169                         if (access < FileAccess.Read || access > FileAccess.ReadWrite)
 170                                 throw new ArgumentOutOfRangeException ("access", "Enum value was out of legal range.");
 171
 172                         if (share < FileShare.None || share > FileShare.ReadWrite)
 173                                 throw new ArgumentOutOfRangeException ("share", "Enum value was out of legal range.");
 174
 175                         if (name.IndexOfAny (Path.InvalidPathChars) != -1) {
 176                                 throw new ArgumentException ("Name has invalid chars");
 177                         }
 178
 179                         if (Directory.Exists (name)) {
 180                                 // don't leak the path information for isolated storage
 181                                 string msg = Locale.GetText ("Access to the path '{0}' is denied.");
 182                                 string fname = (anonymous) ? Path.GetFileName (name) : Path.GetFullPath (name);
 183                                 throw new UnauthorizedAccessException (String.Format (msg, fname));
 184                         }
 185
 186                         /* Append streams can't be read (see FileMode
 187                          * docs)
 188                          */
 189                         if (mode==FileMode.Append &&
 190                                 (access&FileAccess.Read)==FileAccess.Read) {
 191                                 throw new ArgumentException("Append access can be requested only in write-only mode.");
 192                         }
 193
 194                         if ((access & FileAccess.Write) == 0 &&
 195                                 (mode != FileMode.Open && mode != FileMode.OpenOrCreate)) {
 196                                 string msg = Locale.GetText ("Combining FileMode: {0} with " +
 197                                         "FileAccess: {1} is invalid.");
 198                                 throw new ArgumentException (string.Format (msg, access, mode));
 199                         }
 200
 201                         string dname = Path.GetDirectoryName (name);
 202                         if (dname.Length > 0) {
 203                                 string fp = Path.GetFullPath (dname);
 204                                 if (!Directory.Exists (fp)) {
 205                                         // don't leak the path information for isolated storage
 206                                         string msg = Locale.GetText ("Could not find a part of the path \"{0}\".");
 207                                         string fname = (anonymous) ? dname : fp;
 208                                         throw new DirectoryNotFoundException (String.Format (msg, fname));
 209                                 }
 210                         }
 211
 212                         if (access == FileAccess.Read && mode != FileMode.Create && mode != FileMode.OpenOrCreate &&
 213                                         mode != FileMode.CreateNew && !File.Exists (name)) {
 214                                 // don't leak the path information for isolated storage
 215                                 string msg = Locale.GetText ("Could not find file \"{0}\".");
 216                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 217                                 throw new FileNotFoundException (String.Format (msg, fname), fname);
 218                         }
 219
 220                         // IsolatedStorage needs to keep the Name property to the default "[Unknown]"
 221                         if (!anonymous)
 222                                 this.name = name;
 223
 224                         // TODO: demand permissions
 225
 226                         MonoIOError error;
 227
 228                         this.handle = MonoIO.Open (name, mode, access, share, options, out error);
 229                         if (handle == MonoIO.InvalidHandle) {
 230                                 // don't leak the path information for isolated storage
 231                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 232                                 throw MonoIO.GetException (fname, error);
 233                         }
 234
 235                         this.access = access;
 236                         this.owner = true;
 237                         this.anonymous = anonymous;
 238
 239                         /* Can we open non-files by name? */
 240
 241                         if (MonoIO.GetFileType (handle, out error) == MonoFileType.Disk) {
 242                                 this.canseek = true;
 243                                 this.async = (options & FileOptions.Asynchronous) != 0;
 244                         } else {
 245                                 this.canseek = false;
 246                                 this.async = false;
 247                         }
 248
 249
 250                         if (access == FileAccess.Read && canseek && (bufferSize == DefaultBufferSize)) {
 251                                 /* Avoid allocating a large buffer for small files */
 252                                 long len = Length;
 253                                 if (bufferSize > len) {
 254                                         bufferSize = (int)(len < 1000 ? 1000 : len);
 255                                 }
 256                         }
 257
 258                         InitBuffer (bufferSize, false);
 259
 260                         if (mode==FileMode.Append) {
 261                                 this.Seek (0, SeekOrigin.End);
 262                                 this.append_startpos=this.Position;
 263                         } else {
 264                                 this.append_startpos=0;
 265                         }
 266                 }
 267
 268                 // properties
 269
 270                 public override bool CanRead {
 271                         get {
 272                                 return access == FileAccess.Read ||
 273                                        access == FileAccess.ReadWrite;
 274                         }
 275                 }
 276
 277                 public override bool CanWrite {
 278                         get {
 279                                 return access == FileAccess.Write ||
 280                                        access == FileAccess.ReadWrite;
 281                         }
 282                 }
 283
 284                 public override bool CanSeek {
 285                         get {
 286                                 return(canseek);
 287                         }
 288                 }
 289
 290                 public virtual bool IsAsync {
 291                         get {
 292                                 return (async);
 293                         }
 294                 }
 295
 296                 public string Name {
 297                         get {
 298                                 return name;
 299                         }
 300                 }
 301
 302                 public override long Length {
 303                         get {
 304                                 if (handle == MonoIO.InvalidHandle)
 305                                         throw new ObjectDisposedException ("Stream has been closed");
 306
 307                                 if (!CanSeek)
 308                                         throw new NotSupportedException ("The stream does not support seeking");
 309
 310                                 // Buffered data might change the length of the stream
 311                                 FlushBufferIfDirty ();
 312
 313                                 MonoIOError error;
 314                                 long length;
 315
 316                                 length = MonoIO.GetLength (handle, out error);
 317                                 if (error != MonoIOError.ERROR_SUCCESS) {
 318                                         // don't leak the path information for isolated storage
 319                                         string fname = (anonymous) ? Path.GetFileName (name) : name;
 320                                         throw MonoIO.GetException (fname, error);
 321                                 }
 322
 323                                 return(length);
 324                         }
 325                 }
 326
 327                 public override long Position {
 328                         get {
 329                                 if (handle == MonoIO.InvalidHandle)
 330                                         throw new ObjectDisposedException ("Stream has been closed");
 331
 332                                 if(CanSeek == false)
 333                                         throw new NotSupportedException("The stream does not support seeking");
 334
 335                                 return(buf_start + buf_offset);
 336                         }
 337                         set {
 338                                 if (handle == MonoIO.InvalidHandle)
 339                                         throw new ObjectDisposedException ("Stream has been closed");
 340
 341                                 if(CanSeek == false) {
 342                                         throw new NotSupportedException("The stream does not support seeking");
 343                                 }
 344
 345                                 if(value < 0) {
 346                                         throw new ArgumentOutOfRangeException("Attempt to set the position to a negative value");
 347                                 }
 348
 349                                 Seek (value, SeekOrigin.Begin);
 350                         }
 351                 }
 352
 353                 public virtual IntPtr Handle {
 354                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 355                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 356                         get {
 357                                 return handle;
 358                         }
 359                 }
 360
 361 #if NET_2_0
 362                 public virtual SafeFileHandle SafeFileHandle {
 363                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 364                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 365                         get { throw new NotImplementedException (); }
 366                 }
 367 #endif
 368
 369                 // methods
 370
 371                 public override int ReadByte ()
 372                 {
 373                         if (handle == MonoIO.InvalidHandle)
 374                                 throw new ObjectDisposedException ("Stream has been closed");
 375
 376                         if (!CanRead)
 377                                 throw new NotSupportedException ("Stream does not support reading");
 378
 379                         if (buf_size == 0) {
 380                                 int n = ReadData (handle, buf, 0, 1);
 381                                 if (n == 0) return -1;
 382                                 else return buf[0];
 383                         }
 384                         else if (buf_offset >= buf_length) {
 385                                 RefillBuffer ();
 386
 387                                 if (buf_length == 0)
 388                                         return -1;
 389                         }
 390
 391                         return buf [buf_offset ++];
 392                 }
 393
 394                 public override void WriteByte (byte value)
 395                 {
 396                         if (handle == MonoIO.InvalidHandle)
 397                                 throw new ObjectDisposedException ("Stream has been closed");
 398
 399                         if (!CanWrite)
 400                                 throw new NotSupportedException ("Stream does not support writing");
 401
 402                         if (buf_offset == buf_size)
 403                                 FlushBuffer ();
 404
 405                         if (buf_size == 0) { // No buffering
 406                                 buf [0] = value;
 407                                 buf_dirty = true;
 408                                 buf_length = 1;
 409                                 FlushBuffer ();
 410                                 return;
 411                         }
 412
 413                         buf [buf_offset ++] = value;
 414                         if (buf_offset > buf_length)
 415                                 buf_length = buf_offset;
 416
 417                         buf_dirty = true;
 418                 }
 419
 420                 public override int Read ([In,Out] byte[] dest, int dest_offset, int count)
 421                 {
 422                         if (handle == MonoIO.InvalidHandle)
 423                                 throw new ObjectDisposedException ("Stream has been closed");
 424                         if (dest == null)
 425                                 throw new ArgumentNullException ("destFile");
 426                         if (!CanRead)
 427                                 throw new NotSupportedException ("Stream does not support reading");
 428                         int len = dest.Length;
 429                         if (dest_offset < 0)
 430                                 throw new ArgumentOutOfRangeException ("dest_offset", "< 0");
 431                         if (count < 0)
 432                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 433                         if (dest_offset > len)
 434                                 throw new ArgumentException ("destination offset is beyond array size");
 435                         // reordered to avoid possible integer overflow
 436                         if (dest_offset > len - count)
 437                                 throw new ArgumentException ("Reading would overrun buffer");
 438
 439                         if (async) {
 440                                 IAsyncResult ares = BeginRead (dest, dest_offset, count, null, null);
 441                                 return EndRead (ares);
 442                         }
 443
 444                         return ReadInternal (dest, dest_offset, count);
 445                 }
 446
 447                 int ReadInternal (byte [] dest, int dest_offset, int count)
 448                 {
 449                         int copied = 0;
 450
 451                         int n = ReadSegment (dest, dest_offset, count);
 452                         copied += n;
 453                         count -= n;
 454
 455                         if (count == 0) {
 456                                 /* If there was already enough
 457                                  * buffered, no need to read
 458                                  * more from the file.
 459                                  */
 460                                 return (copied);
 461                         }
 462
 463                         if (count > buf_size) {
 464                                 /* Read as much as we can, up
 465                                  * to count bytes
 466                                  */
 467                                 FlushBuffer();
 468                                 n = ReadData (handle, dest,
 469                                               dest_offset+copied,
 470                                               count);
 471
 472                                 /* Make the next buffer read
 473                                  * start from the right place
 474                                  */
 475                                 buf_start += n;
 476                         } else {
 477                                 RefillBuffer ();
 478                                 n = ReadSegment (dest,
 479                                                  dest_offset+copied,
 480                                                  count);
 481                         }
 482
 483                         copied += n;
 484
 485                         return copied;
 486                 }
 487
 488                 delegate int ReadDelegate (byte [] buffer, int offset, int count);
 489
 490                 public override IAsyncResult BeginRead (byte [] buffer, int offset, int count,
 491                                                         AsyncCallback cback, object state)
 492                 {
 493                         if (handle == MonoIO.InvalidHandle)
 494                                 throw new ObjectDisposedException ("Stream has been closed");
 495
 496                         if (!CanRead)
 497                                 throw new NotSupportedException ("This stream does not support reading");
 498
 499                         if (buffer == null)
 500                                 throw new ArgumentNullException ("buffer");
 501
 502                         if (count < 0)
 503                                 throw new ArgumentOutOfRangeException ("count", "Must be >= 0");
 504
 505                         if (offset < 0)
 506                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 507
 508                         // reordered to avoid possible integer overflow
 509                         if (count > buffer.Length - offset)
 510                                 throw new ArgumentException ("Buffer too small. count/offset wrong.");
 511
 512                         if (!async)
 513                                 return base.BeginRead (buffer, offset, count, cback, state);
 514
 515                         ReadDelegate r = new ReadDelegate (ReadInternal);
 516                         return r.BeginInvoke (buffer, offset, count, cback, state);
 517                 }
 518
 519                 public override int EndRead (IAsyncResult async_result)
 520                 {
 521                         if (async_result == null)
 522                                 throw new ArgumentNullException ("async_result");
 523
 524                         if (!async)
 525                                 return base.EndRead (async_result);
 526
 527                         AsyncResult ares = async_result as AsyncResult;
 528                         if (ares == null)
 529                                 throw new ArgumentException ("Invalid IAsyncResult", "async_result");
 530
 531                         ReadDelegate r = ares.AsyncDelegate as ReadDelegate;
 532                         if (r == null)
 533                                 throw new ArgumentException ("Invalid IAsyncResult", "async_result");
 534
 535                         return r.EndInvoke (async_result);
 536                 }
 537
 538                 public override void Write (byte[] src, int src_offset, int count)
 539                 {
 540                         if (handle == MonoIO.InvalidHandle)
 541                                 throw new ObjectDisposedException ("Stream has been closed");
 542                         if (src == null)
 543                                 throw new ArgumentNullException ("src");
 544                         if (src_offset < 0)
 545                                 throw new ArgumentOutOfRangeException ("src_offset", "< 0");
 546                         if (count < 0)
 547                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 548                         // ordered to avoid possible integer overflow
 549                         if (src_offset > src.Length - count)
 550                                 throw new ArgumentException ("Reading would overrun buffer");
 551                         if (!CanWrite)
 552                                 throw new NotSupportedException ("Stream does not support writing");
 553
 554                         if (async) {
 555                                 IAsyncResult ares = BeginWrite (src, src_offset, count, null, null);
 556                                 EndWrite (ares);
 557                                 return;
 558                         }
 559
 560                         WriteInternal (src, src_offset, count);
 561                 }
 562
 563                 void WriteInternal (byte [] src, int src_offset, int count)
 564                 {
 565                         if (count > buf_size) {
 566                                 // shortcut for long writes
 567                                 MonoIOError error;
 568
 569                                 FlushBuffer ();
 570
 571                                 MonoIO.Write (handle, src, src_offset, count, out error);
 572                                 if (error != MonoIOError.ERROR_SUCCESS) {
 573                                         // don't leak the path information for isolated storage
 574                                         string fname = (anonymous) ? Path.GetFileName (name) : name;
 575                                         throw MonoIO.GetException (fname, error);
 576                                 }
 577
 578                                 buf_start += count;
 579                         } else {
 580
 581                                 int copied = 0;
 582                                 while (count > 0) {
 583
 584                                         int n = WriteSegment (src, src_offset + copied, count);
 585                                         copied += n;
 586                                         count -= n;
 587
 588                                         if (count == 0) {
 589                                                 break;
 590                                         }
 591
 592                                         FlushBuffer ();
 593                                 }
 594                         }
 595                 }
 596
 597                 delegate void WriteDelegate (byte [] buffer, int offset, int count);
 598
 599                 public override IAsyncResult BeginWrite (byte [] buffer, int offset, int count,
 600                                                         AsyncCallback cback, object state)
 601                 {
 602                         if (handle == MonoIO.InvalidHandle)
 603                                 throw new ObjectDisposedException ("Stream has been closed");
 604
 605                         if (!CanWrite)
 606                                 throw new NotSupportedException ("This stream does not support writing");
 607
 608                         if (buffer == null)
 609                                 throw new ArgumentNullException ("buffer");
 610
 611                         if (count < 0)
 612                                 throw new ArgumentOutOfRangeException ("count", "Must be >= 0");
 613
 614                         if (offset < 0)
 615                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 616
 617                         // reordered to avoid possible integer overflow
 618                         if (count > buffer.Length - offset)
 619                                 throw new ArgumentException ("Buffer too small. count/offset wrong.");
 620
 621                         if (!async)
 622                                 return base.BeginWrite (buffer, offset, count, cback, state);
 623
 624                         FileStreamAsyncResult result = new FileStreamAsyncResult (cback, state);
 625                         result.BytesRead = -1;
 626                         result.Count = count;
 627                         result.OriginalCount = count;
 628
 629                         if (buf_dirty) {
 630                                 MemoryStream ms = new MemoryStream ();
 631                                 FlushBufferToStream (ms);
 632                                 ms.Write (buffer, offset, count);
 633                                 offset = 0;
 634                                 count = (int) ms.Length;
 635                         }
 636
 637                         WriteDelegate w = new WriteDelegate (WriteInternal);
 638                         return w.BeginInvoke (buffer, offset, count, cback, state);
 639                 }
 640
 641                 public override void EndWrite (IAsyncResult async_result)
 642                 {
 643                         if (async_result == null)
 644                                 throw new ArgumentNullException ("async_result");
 645
 646                         if (!async) {
 647                                 base.EndWrite (async_result);
 648                                 return;
 649                         }
 650
 651                         AsyncResult ares = async_result as AsyncResult;
 652                         if (ares == null)
 653                                 throw new ArgumentException ("Invalid IAsyncResult", "async_result");
 654
 655                         WriteDelegate w = ares.AsyncDelegate as WriteDelegate;
 656                         if (w == null)
 657                                 throw new ArgumentException ("Invalid IAsyncResult", "async_result");
 658
 659                         w.EndInvoke (async_result);
 660                         return;
 661                 }
 662
 663                 public override long Seek (long offset, SeekOrigin origin)
 664                 {
 665                         long pos;
 666
 667                         if (handle == MonoIO.InvalidHandle)
 668                                 throw new ObjectDisposedException ("Stream has been closed");
 669
 670                         // make absolute
 671
 672                         if(CanSeek == false) {
 673                                 throw new NotSupportedException("The stream does not support seeking");
 674                         }
 675
 676                         switch (origin) {
 677                         case SeekOrigin.End:
 678                                 pos = Length + offset;
 679                                 break;
 680
 681                         case SeekOrigin.Current:
 682                                 pos = Position + offset;
 683                                 break;
 684
 685                         case SeekOrigin.Begin:
 686                                 pos = offset;
 687                                 break;
 688
 689                         default:
 690                                 throw new ArgumentException ("origin", "Invalid SeekOrigin");
 691                         }
 692
 693                         if (pos < 0) {
 694                                 /* LAMESPEC: shouldn't this be
 695                                  * ArgumentOutOfRangeException?
 696                                  */
 697                                 throw new IOException("Attempted to Seek before the beginning of the stream");
 698                         }
 699
 700                         if(pos < this.append_startpos) {
 701                                 /* More undocumented crap */
 702                                 throw new IOException("Can't seek back over pre-existing data in append mode");
 703                         }
 704
 705                         FlushBuffer ();
 706
 707                         MonoIOError error;
 708
 709                         buf_start = MonoIO.Seek (handle, pos,
 710                                                  SeekOrigin.Begin,
 711                                                  out error);
 712
 713                         if (error != MonoIOError.ERROR_SUCCESS) {
 714                                 // don't leak the path information for isolated storage
 715                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 716                                 throw MonoIO.GetException (fname, error);
 717                         }
 718
 719                         return(buf_start);
 720                 }
 721
 722                 public override void SetLength (long length)
 723                 {
 724                         if (handle == MonoIO.InvalidHandle)
 725                                 throw new ObjectDisposedException ("Stream has been closed");
 726
 727                         if(CanSeek == false)
 728                                 throw new NotSupportedException("The stream does not support seeking");
 729
 730                         if(CanWrite == false)
 731                                 throw new NotSupportedException("The stream does not support writing");
 732
 733                         if(length < 0)
 734                                 throw new ArgumentOutOfRangeException("Length is less than 0");
 735
 736                         Flush ();
 737
 738                         MonoIOError error;
 739
 740                         MonoIO.SetLength (handle, length, out error);
 741                         if (error != MonoIOError.ERROR_SUCCESS) {
 742                                 // don't leak the path information for isolated storage
 743                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 744                                 throw MonoIO.GetException (fname, error);
 745                         }
 746
 747                         if (Position > length)
 748                                 Position = length;
 749                 }
 750
 751                 public override void Flush ()
 752                 {
 753                         if (handle == MonoIO.InvalidHandle)
 754                                 throw new ObjectDisposedException ("Stream has been closed");
 755
 756                         FlushBuffer ();
 757
 758                         // The flushing is not actually required, in
 759                         //the mono runtime we were mapping flush to
 760                         //`fsync' which is not the same.
 761                         //
 762                         //MonoIO.Flush (handle);
 763                 }
 764
 765                 public override void Close ()
 766                 {
 767                         Dispose (true);
 768                         GC.SuppressFinalize (this);     // remove from finalize queue
 769                 }
 770
 771                 public virtual void Lock (long position, long length)
 772                 {
 773                         if (handle == MonoIO.InvalidHandle)
 774                                 throw new ObjectDisposedException ("Stream has been closed");
 775                         if (position < 0) {
 776                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 777                         }
 778                         if (length < 0) {
 779                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 780                         }
 781                         if (handle == MonoIO.InvalidHandle) {
 782                                 throw new ObjectDisposedException ("Stream has been closed");
 783                         }
 784
 785                         MonoIOError error;
 786
 787                         MonoIO.Lock (handle, position, length, out error);
 788                         if (error != MonoIOError.ERROR_SUCCESS) {
 789                                 // don't leak the path information for isolated storage
 790                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 791                                 throw MonoIO.GetException (fname, error);
 792                         }
 793                 }
 794
 795                 public virtual void Unlock (long position, long length)
 796                 {
 797                         if (handle == MonoIO.InvalidHandle)
 798                                 throw new ObjectDisposedException ("Stream has been closed");
 799                         if (position < 0) {
 800                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 801                         }
 802                         if (length < 0) {
 803                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 804                         }
 805
 806                         MonoIOError error;
 807
 808                         MonoIO.Unlock (handle, position, length, out error);
 809                         if (error != MonoIOError.ERROR_SUCCESS) {
 810                                 // don't leak the path information for isolated storage
 811                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 812                                 throw MonoIO.GetException (fname, error);
 813                         }
 814                 }
 815
 816                 // protected
 817
 818                 ~FileStream ()
 819                 {
 820                         Dispose (false);
 821                 }
 822
 823 #if NET_2_0
 824                 protected override void Dispose (bool disposing)
 825 #else
 826                 protected virtual void Dispose (bool disposing)
 827 #endif
 828                 {
 829                         if (handle != MonoIO.InvalidHandle) {
 830                                 FlushBuffer ();
 831
 832                                 if (owner) {
 833                                         MonoIOError error;
 834
 835                                         MonoIO.Close (handle, out error);
 836                                         if (error != MonoIOError.ERROR_SUCCESS) {
 837                                                 // don't leak the path information for isolated storage
 838                                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 839                                                 throw MonoIO.GetException (fname, error);
 840                                         }
 841
 842                                         handle = MonoIO.InvalidHandle;
 843                                 }
 844                         }
 845
 846                         canseek = false;
 847                         access = 0;
 848                         if (disposing) {
 849                                 buf = null;
 850                         }
 851                 }
 852
 853                 // private.
 854
 855                 // ReadSegment, WriteSegment, FlushBuffer,
 856                 // RefillBuffer and ReadData should only be called
 857                 // when the Monitor lock is held, but these methods
 858                 // grab it again just to be safe.
 859
 860                 private int ReadSegment (byte [] dest, int dest_offset, int count)
 861                 {
 862                         if (count > buf_length - buf_offset) {
 863                                 count = buf_length - buf_offset;
 864                         }
 865
 866                         if (count > 0) {
 867                                 Buffer.BlockCopy (buf, buf_offset,
 868                                                   dest, dest_offset,
 869                                                   count);
 870                                 buf_offset += count;
 871                         }
 872
 873                         return(count);
 874                 }
 875
 876                 private int WriteSegment (byte [] src, int src_offset,
 877                                           int count)
 878                 {
 879                         if (count > buf_size - buf_offset) {
 880                                 count = buf_size - buf_offset;
 881                         }
 882
 883                         if (count > 0) {
 884                                 Buffer.BlockCopy (src, src_offset,
 885                                                   buf, buf_offset,
 886                                                   count);
 887                                 buf_offset += count;
 888                                 if (buf_offset > buf_length) {
 889                                         buf_length = buf_offset;
 890                                 }
 891
 892                                 buf_dirty = true;
 893                         }
 894
 895                         return(count);
 896                 }
 897
 898                 void FlushBufferToStream (Stream st)
 899                 {
 900                         if (buf_dirty) {
 901                                 if (CanSeek == true) {
 902                                         MonoIOError error;
 903                                         MonoIO.Seek (handle, buf_start,
 904                                                      SeekOrigin.Begin,
 905                                                      out error);
 906                                         if (error != MonoIOError.ERROR_SUCCESS) {
 907                                                 // don't leak the path information for isolated storage
 908                                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 909                                                 throw MonoIO.GetException (fname, error);
 910                                         }
 911                                 }
 912                                 st.Write (buf, 0, buf_length);
 913                         }
 914
 915                         buf_start += buf_offset;
 916                         buf_offset = buf_length = 0;
 917                         buf_dirty = false;
 918                 }
 919
 920                 private void FlushBuffer ()
 921                 {
 922                         if (buf_dirty) {
 923                                 MonoIOError error;
 924
 925                                 if (CanSeek == true) {
 926                                         MonoIO.Seek (handle, buf_start,
 927                                                      SeekOrigin.Begin,
 928                                                      out error);
 929                                         if (error != MonoIOError.ERROR_SUCCESS) {
 930                                                 // don't leak the path information for isolated storage
 931                                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 932                                                 throw MonoIO.GetException (fname, error);
 933                                         }
 934                                 }
 935                                 MonoIO.Write (handle, buf, 0,
 936                                               buf_length, out error);
 937
 938                                 if (error != MonoIOError.ERROR_SUCCESS) {
 939                                         // don't leak the path information for isolated storage
 940                                         string fname = (anonymous) ? Path.GetFileName (name) : name;
 941                                         throw MonoIO.GetException (fname, error);
 942                                 }
 943                         }
 944
 945                         buf_start += buf_offset;
 946                         buf_offset = buf_length = 0;
 947                         buf_dirty = false;
 948                 }
 949
 950                 private void FlushBufferIfDirty ()
 951                 {
 952                         if (buf_dirty)
 953                                 FlushBuffer ();
 954                 }
 955
 956                 private void RefillBuffer ()
 957                 {
 958                         FlushBuffer();
 959
 960                         buf_length = ReadData (handle, buf, 0,
 961                                                buf_size);
 962                 }
 963
 964                 private int ReadData (IntPtr handle, byte[] buf, int offset,
 965                                       int count)
 966                 {
 967                         MonoIOError error;
 968                         int amount = 0;
 969
 970                         /* when async == true, if we get here we don't suport AIO or it's disabled
 971                          * and we're using the threadpool */
 972                         amount = MonoIO.Read (handle, buf, offset, count, out error);
 973                         if (error == MonoIOError.ERROR_BROKEN_PIPE) {
 974                                 amount = 0; // might not be needed, but well...
 975                         } else if (error != MonoIOError.ERROR_SUCCESS) {
 976                                 // don't leak the path information for isolated storage
 977                                 string fname = (anonymous) ? Path.GetFileName (name) : name;
 978                                 throw MonoIO.GetException (fname, error);
 979                         }
 980
 981                         /* Check for read error */
 982                         if(amount == -1) {
 983                                 throw new IOException ();
 984                         }
 985
 986                         return(amount);
 987                 }
 988
 989                 private void InitBuffer (int size, bool noBuffering)
 990                 {
 991                         if (noBuffering) {
 992                                 size = 0;
 993                                 // We need a buffer for the ReadByte method. This buffer won't
 994                                 // be used for anything else since buf_size==0.
 995                                 buf = new byte [1];
 996                         }
 997                         else {
 998                                 if (size <= 0)
 999                                         throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
1000                                 if (size < 8)
1001                                         size = 8;
1002                                 buf = new byte [size];
1003                         }
1004
1005                         buf_size = size;
1006                         buf_start = 0;
1007                         buf_offset = buf_length = 0;
1008                         buf_dirty = false;
1009                 }
1010
1011                 // fields
1012
1013                 internal const int DefaultBufferSize = 8192;
1014
1015                 private FileAccess access;
1016                 private bool owner;
1017                 private bool async;
1018                 private bool canseek;
1019                 private long append_startpos;
1020                 private bool anonymous;
1021
1022                 private byte [] buf;                    // the buffer
1023                 private int buf_size;                   // capacity in bytes
1024                 private int buf_length;                 // number of valid bytes in buffer
1025                 private int buf_offset;                 // position of next byte
1026                 private bool buf_dirty;                 // true if buffer has been written to
1027                 private long buf_start;                 // location of buffer in file
1028                 private string name = "[Unknown]";      // name of file.
1029
1030                 IntPtr handle;                          // handle to underlying file
1031         }
1032 }
1033