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 //  Marek Safar (marek.safar@gmail.com)
   9 //
  10 // (C) 2001-2003 Ximian, Inc.  http://www.ximian.com
  11 // Copyright (C) 2004-2005, 2008, 2010 Novell, Inc (http://www.novell.com)
  12 // Copyright 2011 Xamarin Inc (http://www.xamarin.com).
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.Collections;
  35 using System.Globalization;
  36 using System.Runtime.CompilerServices;
  37 using System.Runtime.InteropServices;
  38 using System.Runtime.Remoting.Messaging;
  39 using System.Security;
  40 using System.Security.AccessControl;
  41 using System.Security.Permissions;
  42 using System.Threading;
  43 using System.Threading.Tasks;
  44 using Microsoft.Win32.SafeHandles;
  45
  46 namespace System.IO
  47 {
  48         [ComVisible (true)]
  49         public class FileStream : Stream
  50         {
  51                 // construct from handle
  52
  53                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access) instead")]
  54                 public FileStream (IntPtr handle, FileAccess access)
  55                         : this (handle, access, true, DefaultBufferSize, false, false) {}
  56
  57                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access) instead")]
  58                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle)
  59                         : this (handle, access, ownsHandle, DefaultBufferSize, false, false) {}
  60
  61                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access, int bufferSize) instead")]
  62                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize)
  63                         : this (handle, access, ownsHandle, bufferSize, false, false) {}
  64
  65                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access, int bufferSize, bool isAsync) instead")]
  66                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync)
  67                         : this (handle, access, ownsHandle, bufferSize, isAsync, false) {}
  68
  69                 [SecurityPermission (SecurityAction.Demand, UnmanagedCode = true)]
  70                 internal FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync, bool isConsoleWrapper)
  71                 {
  72                         if (handle == MonoIO.InvalidHandle)
  73                                 throw new ArgumentException ("handle", Locale.GetText ("Invalid."));
  74
  75                         Init (new SafeFileHandle (handle, false), access, ownsHandle, bufferSize, isAsync, isConsoleWrapper);
  76                 }
  77
  78                 // construct from filename
  79
  80                 public FileStream (string path, FileMode mode)
  81                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), FileShare.Read, DefaultBufferSize, false, FileOptions.None)
  82                 {
  83                 }
  84
  85                 public FileStream (string path, FileMode mode, FileAccess access)
  86                         : this (path, mode, access, access == FileAccess.Write ? FileShare.None : FileShare.Read, DefaultBufferSize, false, false)
  87                 {
  88                 }
  89
  90                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share)
  91                         : this (path, mode, access, share, DefaultBufferSize, false, FileOptions.None)
  92                 {
  93                 }
  94
  95                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize)
  96                         : this (path, mode, access, share, bufferSize, false, FileOptions.None)
  97                 {
  98                 }
  99
 100                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool useAsync)
 101                         : this (path, mode, access, share, bufferSize, useAsync ? FileOptions.Asynchronous : FileOptions.None)
 102                 {
 103                 }
 104
 105                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options)
 106                         : this (path, mode, access, share, bufferSize, false, options)
 107                 {
 108                 }
 109
 110                 public FileStream (SafeFileHandle handle, FileAccess access)
 111                         :this(handle, access, DefaultBufferSize, false)
 112                 {
 113                 }
 114
 115                 public FileStream (SafeFileHandle handle, FileAccess access,
 116                                    int bufferSize)
 117                         :this(handle, access, bufferSize, false)
 118                 {
 119                 }
 120
 121                 public FileStream (SafeFileHandle handle, FileAccess access, int bufferSize, bool isAsync)
 122                 {
 123                         Init (handle, access, false, bufferSize, isAsync, false);
 124                 }
 125
 126                 [MonoLimitation ("This ignores the rights parameter")]
 127                 public FileStream (string path, FileMode mode,
 128                                    FileSystemRights rights, FileShare share,
 129                                    int bufferSize, FileOptions options)
 130                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), share, bufferSize, false, options)
 131                 {
 132                 }
 133
 134                 [MonoLimitation ("This ignores the rights and fileSecurity parameters")]
 135                 public FileStream (string path, FileMode mode,
 136                                    FileSystemRights rights, FileShare share,
 137                                    int bufferSize, FileOptions options,
 138                                    FileSecurity fileSecurity)
 139                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), share, bufferSize, false, options)
 140                 {
 141                 }
 142
 143                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options, string msgPath, bool bFromProxy, bool useLongPath = false, bool checkHost = false)
 144                         : this (path, mode, access, share, bufferSize, false, options)
 145                 {
 146                 }
 147
 148                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool isAsync, bool anonymous)
 149                         : this (path, mode, access, share, bufferSize, anonymous, isAsync ? FileOptions.Asynchronous : FileOptions.None)
 150                 {
 151                 }
 152
 153                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool anonymous, FileOptions options)
 154                 {
 155                         if (path == null) {
 156                                 throw new ArgumentNullException ("path");
 157                         }
 158
 159                         if (path.Length == 0) {
 160                                 throw new ArgumentException ("Path is empty");
 161                         }
 162
 163                         this.anonymous = anonymous;
 164                         // ignore the Inheritable flag
 165                         share &= ~FileShare.Inheritable;
 166
 167                         if (bufferSize <= 0)
 168                                 throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
 169
 170                         if (mode < FileMode.CreateNew || mode > FileMode.Append) {
 171 #if MOBILE
 172                                 if (anonymous)
 173                                         throw new ArgumentException ("mode", "Enum value was out of legal range.");
 174                                 else
 175 #endif
 176                                 throw new ArgumentOutOfRangeException ("mode", "Enum value was out of legal range.");
 177                         }
 178
 179                         if (access < FileAccess.Read || access > FileAccess.ReadWrite) {
 180                                 throw new ArgumentOutOfRangeException ("access", "Enum value was out of legal range.");
 181                         }
 182
 183                         if (share < FileShare.None || share > (FileShare.ReadWrite | FileShare.Delete)) {
 184                                 throw new ArgumentOutOfRangeException ("share", "Enum value was out of legal range.");
 185                         }
 186
 187                         if (path.IndexOfAny (Path.InvalidPathChars) != -1) {
 188                                 throw new ArgumentException ("Name has invalid chars");
 189                         }
 190
 191                         path = Path.InsecureGetFullPath (path);
 192
 193                         if (Directory.Exists (path)) {
 194                                 // don't leak the path information for isolated storage
 195                                 string msg = Locale.GetText ("Access to the path '{0}' is denied.");
 196                                 throw new UnauthorizedAccessException (String.Format (msg, GetSecureFileName (path, false)));
 197                         }
 198
 199                         /* Append streams can't be read (see FileMode
 200                          * docs)
 201                          */
 202                         if (mode==FileMode.Append &&
 203                                 (access&FileAccess.Read)==FileAccess.Read) {
 204                                 throw new ArgumentException("Append access can be requested only in write-only mode.");
 205                         }
 206
 207                         if ((access & FileAccess.Write) == 0 &&
 208                                 (mode != FileMode.Open && mode != FileMode.OpenOrCreate)) {
 209                                 string msg = Locale.GetText ("Combining FileMode: {0} with " +
 210                                         "FileAccess: {1} is invalid.");
 211                                 throw new ArgumentException (string.Format (msg, access, mode));
 212                         }
 213
 214                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 215
 216                         string dname = Path.GetDirectoryName (path);
 217                         if (dname.Length > 0) {
 218                                 string fp = Path.GetFullPath (dname);
 219                                 if (!Directory.Exists (fp)) {
 220                                         // don't leak the path information for isolated storage
 221                                         string msg = Locale.GetText ("Could not find a part of the path \"{0}\".");
 222                                         string fname = (anonymous) ? dname : Path.GetFullPath (path);
 223                                         throw new DirectoryNotFoundException (String.Format (msg, fname));
 224                                 }
 225                         }
 226
 227                         // IsolatedStorage needs to keep the Name property to the default "[Unknown]"
 228                         if (!anonymous)
 229                                 this.name = path;
 230
 231                         // TODO: demand permissions
 232
 233                         MonoIOError error;
 234
 235                         var nativeHandle = MonoIO.Open (path, mode, access, share, options, out error);
 236
 237                         if (nativeHandle == MonoIO.InvalidHandle) {
 238                                 // don't leak the path information for isolated storage
 239                                 throw MonoIO.GetException (GetSecureFileName (path), error);
 240                         }
 241
 242                         this.safeHandle = new SafeFileHandle (nativeHandle, false);
 243
 244                         this.access = access;
 245                         this.owner = true;
 246
 247                         /* Can we open non-files by name? */
 248
 249                         if (MonoIO.GetFileType (safeHandle, out error) == MonoFileType.Disk) {
 250                                 this.canseek = true;
 251                                 this.async = (options & FileOptions.Asynchronous) != 0;
 252                         } else {
 253                                 this.canseek = false;
 254                                 this.async = false;
 255                         }
 256
 257
 258                         if (access == FileAccess.Read && canseek && (bufferSize == DefaultBufferSize)) {
 259                                 /* Avoid allocating a large buffer for small files */
 260                                 long len = Length;
 261                                 if (bufferSize > len) {
 262                                         bufferSize = (int)(len < 1000 ? 1000 : len);
 263                                 }
 264                         }
 265
 266                         InitBuffer (bufferSize, false);
 267
 268                         if (mode==FileMode.Append) {
 269                                 this.Seek (0, SeekOrigin.End);
 270                                 this.append_startpos=this.Position;
 271                         } else {
 272                                 this.append_startpos=0;
 273                         }
 274                 }
 275
 276                 private void Init (SafeFileHandle safeHandle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync, bool isConsoleWrapper)
 277                 {
 278                         if (!isConsoleWrapper && safeHandle.IsInvalid)
 279                                 throw new ArgumentException(Environment.GetResourceString("Arg_InvalidHandle"), "handle");
 280                         if (access < FileAccess.Read || access > FileAccess.ReadWrite)
 281                                 throw new ArgumentOutOfRangeException ("access");
 282                         if (!isConsoleWrapper && bufferSize <= 0)
 283                                 throw new ArgumentOutOfRangeException("bufferSize", Environment.GetResourceString("ArgumentOutOfRange_NeedPosNum"));
 284
 285                         MonoIOError error;
 286                         MonoFileType ftype = MonoIO.GetFileType (safeHandle, out error);
 287
 288                         if (error != MonoIOError.ERROR_SUCCESS) {
 289                                 throw MonoIO.GetException (name, error);
 290                         }
 291
 292                         if (ftype == MonoFileType.Unknown) {
 293                                 throw new IOException ("Invalid handle.");
 294                         } else if (ftype == MonoFileType.Disk) {
 295                                 this.canseek = true;
 296                         } else {
 297                                 this.canseek = false;
 298                         }
 299
 300                         this.safeHandle = safeHandle;
 301                         ExposeHandle ();
 302                         this.access = access;
 303                         this.owner = ownsHandle;
 304                         this.async = isAsync;
 305                         this.anonymous = false;
 306
 307                         if (canseek) {
 308                                 buf_start = MonoIO.Seek (safeHandle, 0, SeekOrigin.Current, out error);
 309                                 if (error != MonoIOError.ERROR_SUCCESS) {
 310                                         throw MonoIO.GetException (name, error);
 311                                 }
 312                         }
 313
 314                         /* Can't set append mode */
 315                         this.append_startpos=0;
 316                 }
 317
 318                 // properties
 319
 320                 public override bool CanRead {
 321                         get {
 322                                 return access == FileAccess.Read ||
 323                                        access == FileAccess.ReadWrite;
 324                         }
 325                 }
 326
 327                 public override bool CanWrite {
 328                         get {
 329                                 return access == FileAccess.Write ||
 330                                         access == FileAccess.ReadWrite;
 331                         }
 332                 }
 333
 334                 public override bool CanSeek {
 335                         get {
 336                                 return(canseek);
 337                         }
 338                 }
 339
 340                 public virtual bool IsAsync {
 341                         get {
 342                                 return (async);
 343                         }
 344                 }
 345
 346                 public string Name {
 347                         get {
 348                                 return name;
 349                         }
 350                 }
 351
 352                 public override long Length {
 353                         get {
 354                                 if (safeHandle.IsClosed)
 355                                         throw new ObjectDisposedException ("Stream has been closed");
 356
 357                                 if (!CanSeek)
 358                                         throw new NotSupportedException ("The stream does not support seeking");
 359
 360                                 // Buffered data might change the length of the stream
 361                                 FlushBufferIfDirty ();
 362
 363                                 MonoIOError error;
 364
 365                                 long length = MonoIO.GetLength (safeHandle, out error);
 366
 367                                 if (error != MonoIOError.ERROR_SUCCESS) {
 368                                         // don't leak the path information for isolated storage
 369                                         throw MonoIO.GetException (GetSecureFileName (name), error);
 370                                 }
 371
 372                                 return(length);
 373                         }
 374                 }
 375
 376                 public override long Position {
 377                         get {
 378                                 if (safeHandle.IsClosed)
 379                                         throw new ObjectDisposedException ("Stream has been closed");
 380
 381                                 if (CanSeek == false)
 382                                         throw new NotSupportedException("The stream does not support seeking");
 383
 384                                 if (!isExposed)
 385                                         return(buf_start + buf_offset);
 386
 387                                 // If the handle was leaked outside we always ask the real handle
 388                                 MonoIOError error;
 389
 390                                 long ret = MonoIO.Seek (safeHandle, 0, SeekOrigin.Current, out error);
 391
 392                                 if (error != MonoIOError.ERROR_SUCCESS) {
 393                                         // don't leak the path information for isolated storage
 394                                         throw MonoIO.GetException (GetSecureFileName (name), error);
 395                                 }
 396
 397                                 return ret;
 398                         }
 399                         set {
 400                                 if (value < 0) throw new ArgumentOutOfRangeException("value", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
 401
 402                                 Seek (value, SeekOrigin.Begin);
 403                         }
 404                 }
 405
 406                 [Obsolete ("Use SafeFileHandle instead")]
 407                 public virtual IntPtr Handle {
 408                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 409                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 410                         get {
 411                                 var handle = safeHandle.DangerousGetHandle ();
 412                                 if (!isExposed)
 413                                         ExposeHandle ();
 414                                 return handle;
 415                         }
 416                 }
 417
 418                 public virtual SafeFileHandle SafeFileHandle {
 419                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 420                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 421                         get {
 422                                 if (!isExposed)
 423                                         ExposeHandle ();
 424                                 return safeHandle;
 425                         }
 426                 }
 427
 428                 void ExposeHandle ()
 429                 {
 430                         isExposed = true;
 431                         FlushBuffer ();
 432                         InitBuffer (0, true);
 433                 }
 434
 435                 // methods
 436
 437                 public override int ReadByte ()
 438                 {
 439                         if (safeHandle.IsClosed)
 440                                 throw new ObjectDisposedException ("Stream has been closed");
 441
 442                         if (!CanRead)
 443                                 throw new NotSupportedException ("Stream does not support reading");
 444
 445                         if (buf_size == 0) {
 446                                 int n = ReadData (safeHandle, buf, 0, 1);
 447                                 if (n == 0) return -1;
 448                                 else return buf[0];
 449                         }
 450                         else if (buf_offset >= buf_length) {
 451                                 RefillBuffer ();
 452
 453                                 if (buf_length == 0)
 454                                         return -1;
 455                         }
 456
 457                         return buf [buf_offset ++];
 458                 }
 459
 460                 public override void WriteByte (byte value)
 461                 {
 462                         if (safeHandle.IsClosed)
 463                                 throw new ObjectDisposedException ("Stream has been closed");
 464
 465                         if (!CanWrite)
 466                                 throw new NotSupportedException ("Stream does not support writing");
 467
 468                         if (buf_offset == buf_size)
 469                                 FlushBuffer ();
 470
 471                         if (buf_size == 0) { // No buffering
 472                                 buf [0] = value;
 473                                 buf_dirty = true;
 474                                 buf_length = 1;
 475                                 FlushBuffer ();
 476                                 return;
 477                         }
 478
 479                         buf [buf_offset ++] = value;
 480                         if (buf_offset > buf_length)
 481                                 buf_length = buf_offset;
 482
 483                         buf_dirty = true;
 484                 }
 485
 486                 public override int Read ([In,Out] byte[] array, int offset, int count)
 487                 {
 488                         if (safeHandle.IsClosed)
 489                                 throw new ObjectDisposedException ("Stream has been closed");
 490                         if (array == null)
 491                                 throw new ArgumentNullException ("array");
 492                         if (!CanRead)
 493                                 throw new NotSupportedException ("Stream does not support reading");
 494                         int len = array.Length;
 495                         if (offset < 0)
 496                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 497                         if (count < 0)
 498                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 499                         if (offset > len)
 500                                 throw new ArgumentException ("destination offset is beyond array size");
 501                         // reordered to avoid possible integer overflow
 502                         if (offset > len - count)
 503                                 throw new ArgumentException ("Reading would overrun buffer");
 504
 505                         if (async) {
 506                                 IAsyncResult ares = BeginRead (array, offset, count, null, null);
 507                                 return EndRead (ares);
 508                         }
 509
 510                         return ReadInternal (array, offset, count);
 511                 }
 512
 513                 int ReadInternal (byte [] dest, int offset, int count)
 514                 {
 515                         int n = ReadSegment (dest, offset, count);
 516                         if (n == count) {
 517                                 return count;
 518                         }
 519
 520                         int copied = n;
 521                         count -= n;
 522
 523                         if (count > buf_size) {
 524                                 /* Read as much as we can, up
 525                                  * to count bytes
 526                                  */
 527                                 FlushBuffer();
 528                                 n = ReadData (safeHandle, dest, offset+n, count);
 529
 530                                 /* Make the next buffer read
 531                                  * start from the right place
 532                                  */
 533                                 buf_start += n;
 534                         } else {
 535                                 RefillBuffer ();
 536                                 n = ReadSegment (dest, offset+copied, count);
 537                         }
 538
 539                         return copied + n;
 540                 }
 541
 542                 delegate int ReadDelegate (byte [] buffer, int offset, int count);
 543
 544                 public override IAsyncResult BeginRead (byte [] array, int offset, int numBytes,
 545                                                         AsyncCallback userCallback, object stateObject)
 546                 {
 547                         if (safeHandle.IsClosed)
 548                                 throw new ObjectDisposedException ("Stream has been closed");
 549
 550                         if (!CanRead)
 551                                 throw new NotSupportedException ("This stream does not support reading");
 552
 553                         if (array == null)
 554                                 throw new ArgumentNullException ("array");
 555
 556                         if (numBytes < 0)
 557                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 558
 559                         if (offset < 0)
 560                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 561
 562                         // reordered to avoid possible integer overflow
 563                         if (numBytes > array.Length - offset)
 564                                 throw new ArgumentException ("Buffer too small. numBytes/offset wrong.");
 565
 566                         if (!async)
 567                                 return base.BeginRead (array, offset, numBytes, userCallback, stateObject);
 568
 569                         ReadDelegate r = new ReadDelegate (ReadInternal);
 570                         return r.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 571                 }
 572
 573                 public override int EndRead (IAsyncResult asyncResult)
 574                 {
 575                         if (asyncResult == null)
 576                                 throw new ArgumentNullException ("asyncResult");
 577
 578                         if (!async)
 579                                 return base.EndRead (asyncResult);
 580
 581                         AsyncResult ares = asyncResult as AsyncResult;
 582                         if (ares == null)
 583                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 584
 585                         ReadDelegate r = ares.AsyncDelegate as ReadDelegate;
 586                         if (r == null)
 587                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 588
 589                         return r.EndInvoke (asyncResult);
 590                 }
 591
 592                 public override void Write (byte[] array, int offset, int count)
 593                 {
 594                         if (safeHandle.IsClosed)
 595                                 throw new ObjectDisposedException ("Stream has been closed");
 596                         if (array == null)
 597                                 throw new ArgumentNullException ("array");
 598                         if (offset < 0)
 599                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 600                         if (count < 0)
 601                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 602                         // ordered to avoid possible integer overflow
 603                         if (offset > array.Length - count)
 604                                 throw new ArgumentException ("Reading would overrun buffer");
 605                         if (!CanWrite)
 606                                 throw new NotSupportedException ("Stream does not support writing");
 607
 608                         if (async) {
 609                                 IAsyncResult ares = BeginWrite (array, offset, count, null, null);
 610                                 EndWrite (ares);
 611                                 return;
 612                         }
 613
 614                         WriteInternal (array, offset, count);
 615                 }
 616
 617                 void WriteInternal (byte [] src, int offset, int count)
 618                 {
 619                         if (count > buf_size) {
 620                                 // shortcut for long writes
 621                                 MonoIOError error;
 622
 623                                 FlushBuffer ();
 624
 625                                 if (CanSeek && !isExposed) {
 626                                         MonoIO.Seek (safeHandle, buf_start, SeekOrigin.Begin, out error);
 627                                         if (error != MonoIOError.ERROR_SUCCESS)
 628                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 629                                 }
 630
 631                                 int wcount = count;
 632
 633                                 while (wcount > 0){
 634                                         int n = MonoIO.Write (safeHandle, src, offset, wcount, out error);
 635                                         if (error != MonoIOError.ERROR_SUCCESS)
 636                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 637
 638                                         wcount -= n;
 639                                         offset += n;
 640                                 }
 641                                 buf_start += count;
 642                         } else {
 643
 644                                 int copied = 0;
 645                                 while (count > 0) {
 646
 647                                         int n = WriteSegment (src, offset + copied, count);
 648                                         copied += n;
 649                                         count -= n;
 650
 651                                         if (count == 0) {
 652                                                 break;
 653                                         }
 654
 655                                         FlushBuffer ();
 656                                 }
 657                         }
 658                 }
 659
 660                 delegate void WriteDelegate (byte [] buffer, int offset, int count);
 661
 662                 public override IAsyncResult BeginWrite (byte [] array, int offset, int numBytes,
 663                                                         AsyncCallback userCallback, object stateObject)
 664                 {
 665                         if (safeHandle.IsClosed)
 666                                 throw new ObjectDisposedException ("Stream has been closed");
 667
 668                         if (!CanWrite)
 669                                 throw new NotSupportedException ("This stream does not support writing");
 670
 671                         if (array == null)
 672                                 throw new ArgumentNullException ("array");
 673
 674                         if (numBytes < 0)
 675                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 676
 677                         if (offset < 0)
 678                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 679
 680                         // reordered to avoid possible integer overflow
 681                         if (numBytes > array.Length - offset)
 682                                 throw new ArgumentException ("array too small. numBytes/offset wrong.");
 683
 684                         if (!async)
 685                                 return base.BeginWrite (array, offset, numBytes, userCallback, stateObject);
 686
 687                         FileStreamAsyncResult result = new FileStreamAsyncResult (userCallback, stateObject);
 688                         result.BytesRead = -1;
 689                         result.Count = numBytes;
 690                         result.OriginalCount = numBytes;
 691 /*
 692                         if (buf_dirty) {
 693                                 MemoryStream ms = new MemoryStream ();
 694                                 FlushBuffer (ms);
 695                                 ms.Write (array, offset, numBytes);
 696
 697                                 // Set arguments to new compounded buffer
 698                                 offset = 0;
 699                                 array = ms.ToArray ();
 700                                 numBytes = array.Length;
 701                         }
 702 */
 703                         WriteDelegate w = WriteInternal;
 704                         return w.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 705                 }
 706
 707                 public override void EndWrite (IAsyncResult asyncResult)
 708                 {
 709                         if (asyncResult == null)
 710                                 throw new ArgumentNullException ("asyncResult");
 711
 712                         if (!async) {
 713                                 base.EndWrite (asyncResult);
 714                                 return;
 715                         }
 716
 717                         AsyncResult ares = asyncResult as AsyncResult;
 718                         if (ares == null)
 719                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 720
 721                         WriteDelegate w = ares.AsyncDelegate as WriteDelegate;
 722                         if (w == null)
 723                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 724
 725                         w.EndInvoke (asyncResult);
 726                         return;
 727                 }
 728
 729                 public override long Seek (long offset, SeekOrigin origin)
 730                 {
 731                         long pos;
 732
 733                         if (safeHandle.IsClosed)
 734                                 throw new ObjectDisposedException ("Stream has been closed");
 735
 736                         // make absolute
 737
 738                         if(CanSeek == false) {
 739                                 throw new NotSupportedException("The stream does not support seeking");
 740                         }
 741
 742                         switch (origin) {
 743                         case SeekOrigin.End:
 744                                 pos = Length + offset;
 745                                 break;
 746
 747                         case SeekOrigin.Current:
 748                                 pos = Position + offset;
 749                                 break;
 750
 751                         case SeekOrigin.Begin:
 752                                 pos = offset;
 753                                 break;
 754
 755                         default:
 756                                 throw new ArgumentException ("origin", "Invalid SeekOrigin");
 757                         }
 758
 759                         if (pos < 0) {
 760                                 /* LAMESPEC: shouldn't this be
 761                                  * ArgumentOutOfRangeException?
 762                                  */
 763                                 throw new IOException("Attempted to Seek before the beginning of the stream");
 764                         }
 765
 766                         if(pos < this.append_startpos) {
 767                                 /* More undocumented crap */
 768                                 throw new IOException("Can't seek back over pre-existing data in append mode");
 769                         }
 770
 771                         FlushBuffer ();
 772
 773                         MonoIOError error;
 774
 775                         buf_start = MonoIO.Seek (safeHandle, pos, SeekOrigin.Begin, out error);
 776
 777                         if (error != MonoIOError.ERROR_SUCCESS) {
 778                                 // don't leak the path information for isolated storage
 779                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 780                         }
 781
 782                         return(buf_start);
 783                 }
 784
 785                 public override void SetLength (long value)
 786                 {
 787                         if (safeHandle.IsClosed)
 788                                 throw new ObjectDisposedException ("Stream has been closed");
 789
 790                         if(CanSeek == false)
 791                                 throw new NotSupportedException("The stream does not support seeking");
 792
 793                         if(CanWrite == false)
 794                                 throw new NotSupportedException("The stream does not support writing");
 795
 796                         if(value < 0)
 797                                 throw new ArgumentOutOfRangeException("value is less than 0");
 798
 799                         FlushBuffer ();
 800
 801                         MonoIOError error;
 802
 803                         MonoIO.SetLength (safeHandle, value, out error);
 804                         if (error != MonoIOError.ERROR_SUCCESS) {
 805                                 // don't leak the path information for isolated storage
 806                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 807                         }
 808
 809                         if (Position > value)
 810                                 Position = value;
 811                 }
 812
 813                 public override void Flush ()
 814                 {
 815                         if (safeHandle.IsClosed)
 816                                 throw new ObjectDisposedException ("Stream has been closed");
 817
 818                         FlushBuffer ();
 819                 }
 820
 821                 public virtual void Flush (bool flushToDisk)
 822                 {
 823                         if (safeHandle.IsClosed)
 824                                 throw new ObjectDisposedException ("Stream has been closed");
 825
 826                         FlushBuffer ();
 827
 828                         // This does the fsync
 829                         if (flushToDisk){
 830                                 MonoIOError error;
 831                                 MonoIO.Flush (safeHandle, out error);
 832                         }
 833                 }
 834
 835                 public virtual void Lock (long position, long length)
 836                 {
 837                         if (safeHandle.IsClosed)
 838                                 throw new ObjectDisposedException ("Stream has been closed");
 839                         if (position < 0) {
 840                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 841                         }
 842                         if (length < 0) {
 843                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 844                         }
 845
 846                         MonoIOError error;
 847
 848                         MonoIO.Lock (safeHandle, position, length, out error);
 849                         if (error != MonoIOError.ERROR_SUCCESS) {
 850                                 // don't leak the path information for isolated storage
 851                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 852                         }
 853                 }
 854
 855                 public virtual void Unlock (long position, long length)
 856                 {
 857                         if (safeHandle.IsClosed)
 858                                 throw new ObjectDisposedException ("Stream has been closed");
 859                         if (position < 0) {
 860                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 861                         }
 862                         if (length < 0) {
 863                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 864                         }
 865
 866                         MonoIOError error;
 867
 868                         MonoIO.Unlock (safeHandle, position, length, out error);
 869                         if (error != MonoIOError.ERROR_SUCCESS) {
 870                                 // don't leak the path information for isolated storage
 871                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 872                         }
 873                 }
 874
 875                 // protected
 876
 877                 ~FileStream ()
 878                 {
 879                         Dispose (false);
 880                 }
 881
 882                 protected override void Dispose (bool disposing)
 883                 {
 884                         Exception exc = null;
 885                         if (safeHandle != null && !safeHandle.IsClosed) {
 886                                 try {
 887                                         // If the FileStream is in "exposed" status
 888                                         // it means that we do not have a buffer(we write the data without buffering)
 889                                         // therefor we don't and can't flush the buffer becouse we don't have one.
 890                                         FlushBuffer ();
 891                                 } catch (Exception e) {
 892                                         exc = e;
 893                                 }
 894
 895                                 if (owner) {
 896                                         MonoIOError error;
 897
 898                                         MonoIO.Close (safeHandle.DangerousGetHandle (), out error);
 899                                         if (error != MonoIOError.ERROR_SUCCESS) {
 900                                                 // don't leak the path information for isolated storage
 901                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 902                                         }
 903
 904                                         safeHandle.DangerousRelease ();
 905                                 }
 906                         }
 907
 908                         canseek = false;
 909                         access = 0;
 910
 911                         if (disposing && buf != null) {
 912                                 if (buf.Length == DefaultBufferSize && buf_recycle == null) {
 913                                         lock (buf_recycle_lock) {
 914                                                 if (buf_recycle == null) {
 915                                                         buf_recycle = buf;
 916                                                 }
 917                                         }
 918                                 }
 919
 920                                 buf = null;
 921                                 GC.SuppressFinalize (this);
 922                         }
 923                         if (exc != null)
 924                                 throw exc;
 925                 }
 926
 927                 public FileSecurity GetAccessControl ()
 928                 {
 929                         if (safeHandle.IsClosed)
 930                                 throw new ObjectDisposedException ("Stream has been closed");
 931
 932                         return new FileSecurity (SafeFileHandle,
 933                                                  AccessControlSections.Owner |
 934                                                  AccessControlSections.Group |
 935                                                  AccessControlSections.Access);
 936                 }
 937
 938                 public void SetAccessControl (FileSecurity fileSecurity)
 939                 {
 940                         if (safeHandle.IsClosed)
 941                                 throw new ObjectDisposedException ("Stream has been closed");
 942
 943                         if (null == fileSecurity)
 944                                 throw new ArgumentNullException ("fileSecurity");
 945
 946                         fileSecurity.PersistModifications (SafeFileHandle);
 947                 }
 948
 949                 public override Task FlushAsync (CancellationToken cancellationToken)
 950                 {
 951                         if (safeHandle.IsClosed)
 952                                 throw new ObjectDisposedException ("Stream has been closed");
 953
 954                         return base.FlushAsync (cancellationToken);
 955                 }
 956
 957                 public override Task<int> ReadAsync (byte[] buffer, int offset, int count, CancellationToken cancellationToken)
 958                 {
 959                         return base.ReadAsync (buffer, offset, count, cancellationToken);
 960                 }
 961
 962                 public override Task WriteAsync (byte[] buffer, int offset, int count, CancellationToken cancellationToken)
 963                 {
 964                         return base.WriteAsync (buffer, offset, count, cancellationToken);
 965                 }
 966
 967                 // private.
 968
 969                 // ReadSegment, WriteSegment, FlushBuffer,
 970                 // RefillBuffer and ReadData should only be called
 971                 // when the Monitor lock is held, but these methods
 972                 // grab it again just to be safe.
 973
 974                 private int ReadSegment (byte [] dest, int dest_offset, int count)
 975                 {
 976                         count = Math.Min (count, buf_length - buf_offset);
 977
 978                         if (count > 0) {
 979                                 // Use the fastest method, all range checks has been done
 980                                 Buffer.InternalBlockCopy (buf, buf_offset, dest, dest_offset, count);
 981                                 buf_offset += count;
 982                         }
 983
 984                         return count;
 985                 }
 986
 987                 private int WriteSegment (byte [] src, int src_offset,
 988                                           int count)
 989                 {
 990                         if (count > buf_size - buf_offset) {
 991                                 count = buf_size - buf_offset;
 992                         }
 993
 994                         if (count > 0) {
 995                                 Buffer.BlockCopy (src, src_offset,
 996                                                   buf, buf_offset,
 997                                                   count);
 998                                 buf_offset += count;
 999                                 if (buf_offset > buf_length) {
1000                                         buf_length = buf_offset;
1001                                 }
1002
1003                                 buf_dirty = true;
1004                         }
1005
1006                         return(count);
1007                 }
1008
1009                 void FlushBuffer ()
1010                 {
1011                         if (buf_dirty) {
1012 //                              if (st == null) {
1013                                         MonoIOError error;
1014
1015                                         if (CanSeek == true && !isExposed) {
1016                                                 MonoIO.Seek (safeHandle, buf_start, SeekOrigin.Begin, out error);
1017
1018                                                 if (error != MonoIOError.ERROR_SUCCESS) {
1019                                                         // don't leak the path information for isolated storage
1020                                                         throw MonoIO.GetException (GetSecureFileName (name), error);
1021                                                 }
1022                                         }
1023
1024                                         int wcount = buf_length;
1025                                         int offset = 0;
1026                                         while (wcount > 0){
1027                                                 int n = MonoIO.Write (safeHandle, buf, offset, buf_length, out error);
1028                                                 if (error != MonoIOError.ERROR_SUCCESS) {
1029                                                         // don't leak the path information for isolated storage
1030                                                         throw MonoIO.GetException (GetSecureFileName (name), error);
1031                                                 }
1032                                                 wcount -= n;
1033                                                 offset += n;
1034                                         }
1035 //                              } else {
1036 //                                      st.Write (buf, 0, buf_length);
1037 //                              }
1038                         }
1039
1040                         buf_start += buf_offset;
1041                         buf_offset = buf_length = 0;
1042                         buf_dirty = false;
1043                 }
1044
1045                 private void FlushBufferIfDirty ()
1046                 {
1047                         if (buf_dirty)
1048                                 FlushBuffer ();
1049                 }
1050
1051                 private void RefillBuffer ()
1052                 {
1053                         FlushBuffer ();
1054
1055                         buf_length = ReadData (safeHandle, buf, 0, buf_size);
1056                 }
1057
1058                 private int ReadData (SafeHandle safeHandle, byte[] buf, int offset,
1059                                       int count)
1060                 {
1061                         MonoIOError error;
1062                         int amount = 0;
1063
1064                         /* when async == true, if we get here we don't suport AIO or it's disabled
1065                          * and we're using the threadpool */
1066                         amount = MonoIO.Read (safeHandle, buf, offset, count, out error);
1067                         if (error == MonoIOError.ERROR_BROKEN_PIPE) {
1068                                 amount = 0; // might not be needed, but well...
1069                         } else if (error != MonoIOError.ERROR_SUCCESS) {
1070                                 // don't leak the path information for isolated storage
1071                                 throw MonoIO.GetException (GetSecureFileName (name), error);
1072                         }
1073
1074                         /* Check for read error */
1075                         if(amount == -1) {
1076                                 throw new IOException ();
1077                         }
1078
1079                         return(amount);
1080                 }
1081
1082                 void InitBuffer (int size, bool isZeroSize)
1083                 {
1084                         if (isZeroSize) {
1085                                 size = 0;
1086                                 buf = new byte[1];
1087                         } else {
1088                                 if (size <= 0)
1089                                         throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
1090
1091                                 size = Math.Max (size, 8);
1092
1093                                 //
1094                                 // Instead of allocating a new default buffer use the
1095                                 // last one if there is any available
1096                                 //
1097                                 if (size <= DefaultBufferSize && buf_recycle != null) {
1098                                         lock (buf_recycle_lock) {
1099                                                 if (buf_recycle != null) {
1100                                                         buf = buf_recycle;
1101                                                         buf_recycle = null;
1102                                                 }
1103                                         }
1104                                 }
1105
1106                                 if (buf == null)
1107                                         buf = new byte [size];
1108                                 else
1109                                         Array.Clear (buf, 0, size);
1110                         }
1111
1112                         buf_size = size;
1113 //                      buf_start = 0;
1114 //                      buf_offset = buf_length = 0;
1115 //                      buf_dirty = false;
1116                 }
1117
1118                 private string GetSecureFileName (string filename)
1119                 {
1120                         return (anonymous) ? Path.GetFileName (filename) : Path.GetFullPath (filename);
1121                 }
1122
1123                 private string GetSecureFileName (string filename, bool full)
1124                 {
1125                         return (anonymous) ? Path.GetFileName (filename) :
1126                                 (full) ? Path.GetFullPath (filename) : filename;
1127                 }
1128
1129                 // fields
1130
1131                 internal const int DefaultBufferSize = 4096;
1132
1133                 // Input buffer ready for recycling
1134                 static byte[] buf_recycle;
1135                 static readonly object buf_recycle_lock = new object ();
1136
1137                 private byte [] buf;                    // the buffer
1138                 private string name = "[Unknown]";      // name of file.
1139
1140                 private SafeFileHandle safeHandle;
1141                 private bool isExposed;
1142
1143                 private long append_startpos;
1144
1145                 private FileAccess access;
1146                 private bool owner;
1147                 private bool async;
1148                 private bool canseek;
1149                 private bool anonymous;
1150                 private bool buf_dirty;                 // true if buffer has been written to
1151
1152                 private int buf_size;                   // capacity in bytes
1153                 private int buf_length;                 // number of valid bytes in buffer
1154                 private int buf_offset;                 // position of next byte
1155                 private long buf_start;                 // location of buffer in file
1156         }
1157 }