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.Permissions;
  41 using System.Threading;
  42 using Microsoft.Win32.SafeHandles;
  43
  44 #if NET_2_1
  45 using System.IO.IsolatedStorage;
  46 #else
  47 using System.Security.AccessControl;
  48 #endif
  49
  50 using System.Threading.Tasks;
  51
  52 namespace System.IO
  53 {
  54         [ComVisible (true)]
  55         public class FileStream : Stream
  56         {
  57                 // construct from handle
  58
  59                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access) instead")]
  60                 public FileStream (IntPtr handle, FileAccess access)
  61                         : this (handle, access, true, DefaultBufferSize, false, false) {}
  62
  63                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access) instead")]
  64                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle)
  65                         : this (handle, access, ownsHandle, DefaultBufferSize, false, false) {}
  66
  67                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access, int bufferSize) instead")]
  68                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize)
  69                         : this (handle, access, ownsHandle, bufferSize, false, false) {}
  70
  71                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access, int bufferSize, bool isAsync) instead")]
  72                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync)
  73                         : this (handle, access, ownsHandle, bufferSize, isAsync, false) {}
  74
  75                 [SecurityPermission (SecurityAction.Demand, UnmanagedCode = true)]
  76                 internal FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync, bool isZeroSize)
  77                 {
  78                         if (handle == MonoIO.InvalidHandle)
  79                                 throw new ArgumentException ("handle", Locale.GetText ("Invalid."));
  80
  81                         Init (new SafeFileHandle (handle, false), access, ownsHandle, bufferSize, isAsync, isZeroSize);
  82                 }
  83
  84                 // construct from filename
  85
  86                 public FileStream (string path, FileMode mode)
  87                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), FileShare.Read, DefaultBufferSize, false, FileOptions.None)
  88                 {
  89                 }
  90
  91                 public FileStream (string path, FileMode mode, FileAccess access)
  92                         : this (path, mode, access, access == FileAccess.Write ? FileShare.None : FileShare.Read, DefaultBufferSize, false, false)
  93                 {
  94                 }
  95
  96                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share)
  97                         : this (path, mode, access, share, DefaultBufferSize, false, FileOptions.None)
  98                 {
  99                 }
 100
 101                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize)
 102                         : this (path, mode, access, share, bufferSize, false, FileOptions.None)
 103                 {
 104                 }
 105
 106                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool useAsync)
 107                         : this (path, mode, access, share, bufferSize, useAsync ? FileOptions.Asynchronous : FileOptions.None)
 108                 {
 109                 }
 110
 111                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options)
 112                         : this (path, mode, access, share, bufferSize, false, options)
 113                 {
 114                 }
 115
 116 #if !NET_2_1
 117                 public FileStream (SafeFileHandle handle, FileAccess access)
 118                         :this(handle, access, DefaultBufferSize, false)
 119                 {
 120                 }
 121
 122                 public FileStream (SafeFileHandle handle, FileAccess access,
 123                                    int bufferSize)
 124                         :this(handle, access, bufferSize, false)
 125                 {
 126                 }
 127
 128                 public FileStream (SafeFileHandle handle, FileAccess access, int bufferSize, bool isAsync)
 129                 {
 130                         Init (handle, access, false, bufferSize, isAsync, false);
 131                 }
 132
 133                 [MonoLimitation ("This ignores the rights parameter")]
 134                 public FileStream (string path, FileMode mode,
 135                                    FileSystemRights rights, FileShare share,
 136                                    int bufferSize, FileOptions options)
 137                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), share, bufferSize, false, options)
 138                 {
 139                 }
 140
 141                 [MonoLimitation ("This ignores the rights and fileSecurity parameters")]
 142                 public FileStream (string path, FileMode mode,
 143                                    FileSystemRights rights, FileShare share,
 144                                    int bufferSize, FileOptions options,
 145                                    FileSecurity fileSecurity)
 146                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), share, bufferSize, false, options)
 147                 {
 148                 }
 149 #endif
 150
 151                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options, string msgPath, bool bFromProxy, bool useLongPath, bool checkHost)
 152                         : this (path, mode, access, share, bufferSize, false, options)
 153                 {
 154                 }
 155
 156                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool isAsync, bool anonymous)
 157                         : this (path, mode, access, share, bufferSize, anonymous, isAsync ? FileOptions.Asynchronous : FileOptions.None)
 158                 {
 159                 }
 160
 161                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool anonymous, FileOptions options)
 162                 {
 163                         if (path == null) {
 164                                 throw new ArgumentNullException ("path");
 165                         }
 166
 167                         if (path.Length == 0) {
 168                                 throw new ArgumentException ("Path is empty");
 169                         }
 170
 171                         this.anonymous = anonymous;
 172                         // ignore the Inheritable flag
 173                         share &= ~FileShare.Inheritable;
 174
 175                         if (bufferSize <= 0)
 176                                 throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
 177
 178                         if (mode < FileMode.CreateNew || mode > FileMode.Append) {
 179 #if NET_2_1
 180                                 if (anonymous)
 181                                         throw new ArgumentException ("mode", "Enum value was out of legal range.");
 182                                 else
 183 #endif
 184                                 throw new ArgumentOutOfRangeException ("mode", "Enum value was out of legal range.");
 185                         }
 186
 187                         if (access < FileAccess.Read || access > FileAccess.ReadWrite) {
 188                                 throw new ArgumentOutOfRangeException ("access", "Enum value was out of legal range.");
 189                         }
 190
 191                         if (share < FileShare.None || share > (FileShare.ReadWrite | FileShare.Delete)) {
 192                                 throw new ArgumentOutOfRangeException ("share", "Enum value was out of legal range.");
 193                         }
 194
 195                         if (path.IndexOfAny (Path.InvalidPathChars) != -1) {
 196                                 throw new ArgumentException ("Name has invalid chars");
 197                         }
 198
 199                         if (Directory.Exists (path)) {
 200                                 // don't leak the path information for isolated storage
 201                                 string msg = Locale.GetText ("Access to the path '{0}' is denied.");
 202                                 throw new UnauthorizedAccessException (String.Format (msg, GetSecureFileName (path, false)));
 203                         }
 204
 205                         /* Append streams can't be read (see FileMode
 206                          * docs)
 207                          */
 208                         if (mode==FileMode.Append &&
 209                                 (access&FileAccess.Read)==FileAccess.Read) {
 210                                 throw new ArgumentException("Append access can be requested only in write-only mode.");
 211                         }
 212
 213                         if ((access & FileAccess.Write) == 0 &&
 214                                 (mode != FileMode.Open && mode != FileMode.OpenOrCreate)) {
 215                                 string msg = Locale.GetText ("Combining FileMode: {0} with " +
 216                                         "FileAccess: {1} is invalid.");
 217                                 throw new ArgumentException (string.Format (msg, access, mode));
 218                         }
 219
 220                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 221
 222                         string dname;
 223                         if (Path.DirectorySeparatorChar != '/' && path.IndexOf ('/') >= 0)
 224                                 dname = Path.GetDirectoryName (Path.GetFullPath (path));
 225                         else
 226                                 dname = Path.GetDirectoryName (path);
 227                         if (dname.Length > 0) {
 228                                 string fp = Path.GetFullPath (dname);
 229                                 if (!Directory.Exists (fp)) {
 230                                         // don't leak the path information for isolated storage
 231                                         string msg = Locale.GetText ("Could not find a part of the path \"{0}\".");
 232                                         string fname = (anonymous) ? dname : Path.GetFullPath (path);
 233                                         throw new DirectoryNotFoundException (String.Format (msg, fname));
 234                                 }
 235                         }
 236
 237                         if (access == FileAccess.Read && mode != FileMode.Create && mode != FileMode.OpenOrCreate &&
 238                                         mode != FileMode.CreateNew && !File.Exists (path)) {
 239                                 // don't leak the path information for isolated storage
 240                                 string msg = Locale.GetText ("Could not find file \"{0}\".");
 241                                 string fname = GetSecureFileName (path);
 242                                 throw new FileNotFoundException (String.Format (msg, fname), fname);
 243                         }
 244
 245                         // IsolatedStorage needs to keep the Name property to the default "[Unknown]"
 246                         if (!anonymous)
 247                                 this.name = path;
 248
 249                         // TODO: demand permissions
 250
 251                         MonoIOError error;
 252
 253                         var nativeHandle = MonoIO.Open (path, mode, access, share, options, out error);
 254
 255                         if (nativeHandle == MonoIO.InvalidHandle) {
 256                                 // don't leak the path information for isolated storage
 257                                 throw MonoIO.GetException (GetSecureFileName (path), error);
 258                         }
 259
 260                         this.safeHandle = new SafeFileHandle (nativeHandle, false);
 261
 262                         this.access = access;
 263                         this.owner = true;
 264
 265                         /* Can we open non-files by name? */
 266
 267                         if (MonoIO.GetFileType (safeHandle, out error) == MonoFileType.Disk) {
 268                                 this.canseek = true;
 269                                 this.async = (options & FileOptions.Asynchronous) != 0;
 270                         } else {
 271                                 this.canseek = false;
 272                                 this.async = false;
 273                         }
 274
 275
 276                         if (access == FileAccess.Read && canseek && (bufferSize == DefaultBufferSize)) {
 277                                 /* Avoid allocating a large buffer for small files */
 278                                 long len = Length;
 279                                 if (bufferSize > len) {
 280                                         bufferSize = (int)(len < 1000 ? 1000 : len);
 281                                 }
 282                         }
 283
 284                         InitBuffer (bufferSize, false);
 285
 286                         if (mode==FileMode.Append) {
 287                                 this.Seek (0, SeekOrigin.End);
 288                                 this.append_startpos=this.Position;
 289                         } else {
 290                                 this.append_startpos=0;
 291                         }
 292                 }
 293
 294                 private void Init (SafeFileHandle safeHandle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync, bool isZeroSize)
 295                 {
 296                         if (access < FileAccess.Read || access > FileAccess.ReadWrite)
 297                                 throw new ArgumentOutOfRangeException ("access");
 298
 299                         MonoIOError error;
 300                         MonoFileType ftype = MonoIO.GetFileType (safeHandle, out error);
 301
 302                         if (error != MonoIOError.ERROR_SUCCESS) {
 303                                 throw MonoIO.GetException (name, error);
 304                         }
 305
 306                         if (ftype == MonoFileType.Unknown) {
 307                                 throw new IOException ("Invalid handle.");
 308                         } else if (ftype == MonoFileType.Disk) {
 309                                 this.canseek = true;
 310                         } else {
 311                                 this.canseek = false;
 312                         }
 313
 314                         this.safeHandle = safeHandle;
 315                         ExposeHandle ();
 316                         this.access = access;
 317                         this.owner = ownsHandle;
 318                         this.async = isAsync;
 319                         this.anonymous = false;
 320
 321                         if (canseek) {
 322                                 buf_start = MonoIO.Seek (safeHandle, 0, SeekOrigin.Current, out error);
 323                                 if (error != MonoIOError.ERROR_SUCCESS) {
 324                                         throw MonoIO.GetException (name, error);
 325                                 }
 326                         }
 327
 328                         /* Can't set append mode */
 329                         this.append_startpos=0;
 330                 }
 331
 332                 // properties
 333
 334                 public override bool CanRead {
 335                         get {
 336                                 return access == FileAccess.Read ||
 337                                        access == FileAccess.ReadWrite;
 338                         }
 339                 }
 340
 341                 public override bool CanWrite {
 342                         get {
 343                                 return access == FileAccess.Write ||
 344                                         access == FileAccess.ReadWrite;
 345                         }
 346                 }
 347
 348                 public override bool CanSeek {
 349                         get {
 350                                 return(canseek);
 351                         }
 352                 }
 353
 354                 public virtual bool IsAsync {
 355                         get {
 356                                 return (async);
 357                         }
 358                 }
 359
 360                 public string Name {
 361                         get {
 362                                 return name;
 363                         }
 364                 }
 365
 366                 public override long Length {
 367                         get {
 368                                 if (safeHandle.IsClosed)
 369                                         throw new ObjectDisposedException ("Stream has been closed");
 370
 371                                 if (!CanSeek)
 372                                         throw new NotSupportedException ("The stream does not support seeking");
 373
 374                                 // Buffered data might change the length of the stream
 375                                 FlushBufferIfDirty ();
 376
 377                                 MonoIOError error;
 378
 379                                 long length = MonoIO.GetLength (safeHandle, out error);
 380
 381                                 if (error != MonoIOError.ERROR_SUCCESS) {
 382                                         // don't leak the path information for isolated storage
 383                                         throw MonoIO.GetException (GetSecureFileName (name), error);
 384                                 }
 385
 386                                 return(length);
 387                         }
 388                 }
 389
 390                 public override long Position {
 391                         get {
 392                                 if (safeHandle.IsClosed)
 393                                         throw new ObjectDisposedException ("Stream has been closed");
 394
 395                                 if (CanSeek == false)
 396                                         throw new NotSupportedException("The stream does not support seeking");
 397
 398                                 if (!isExposed)
 399                                         return(buf_start + buf_offset);
 400
 401                                 // If the handle was leaked outside we always ask the real handle
 402                                 MonoIOError error;
 403
 404                                 long ret = MonoIO.Seek (safeHandle, 0, SeekOrigin.Current, out error);
 405
 406                                 if (error != MonoIOError.ERROR_SUCCESS) {
 407                                         // don't leak the path information for isolated storage
 408                                         throw MonoIO.GetException (GetSecureFileName (name), error);
 409                                 }
 410
 411                                 return ret;
 412                         }
 413                         set {
 414                                 if(value < 0) {
 415                                         throw new ArgumentOutOfRangeException("Attempt to set the position to a negative value");
 416                                 }
 417
 418                                 Seek (value, SeekOrigin.Begin);
 419                         }
 420                 }
 421
 422                 [Obsolete ("Use SafeFileHandle instead")]
 423                 public virtual IntPtr Handle {
 424                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 425                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 426                         get {
 427                                 var handle = safeHandle.DangerousGetHandle ();
 428                                 if (!isExposed)
 429                                         ExposeHandle ();
 430                                 return handle;
 431                         }
 432                 }
 433
 434                 public virtual SafeFileHandle SafeFileHandle {
 435                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 436                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 437                         get {
 438                                 if (!isExposed)
 439                                         ExposeHandle ();
 440                                 return safeHandle;
 441                         }
 442                 }
 443
 444                 void ExposeHandle ()
 445                 {
 446                         isExposed = true;
 447                         FlushBuffer ();
 448                         InitBuffer (0, true);
 449                 }
 450
 451                 // methods
 452
 453                 public override int ReadByte ()
 454                 {
 455                         if (safeHandle.IsClosed)
 456                                 throw new ObjectDisposedException ("Stream has been closed");
 457
 458                         if (!CanRead)
 459                                 throw new NotSupportedException ("Stream does not support reading");
 460
 461                         if (buf_size == 0) {
 462                                 int n = ReadData (safeHandle, buf, 0, 1);
 463                                 if (n == 0) return -1;
 464                                 else return buf[0];
 465                         }
 466                         else if (buf_offset >= buf_length) {
 467                                 RefillBuffer ();
 468
 469                                 if (buf_length == 0)
 470                                         return -1;
 471                         }
 472
 473                         return buf [buf_offset ++];
 474                 }
 475
 476                 public override void WriteByte (byte value)
 477                 {
 478                         if (safeHandle.IsClosed)
 479                                 throw new ObjectDisposedException ("Stream has been closed");
 480
 481                         if (!CanWrite)
 482                                 throw new NotSupportedException ("Stream does not support writing");
 483
 484                         if (buf_offset == buf_size)
 485                                 FlushBuffer ();
 486
 487                         if (buf_size == 0) { // No buffering
 488                                 buf [0] = value;
 489                                 buf_dirty = true;
 490                                 buf_length = 1;
 491                                 FlushBuffer ();
 492                                 return;
 493                         }
 494
 495                         buf [buf_offset ++] = value;
 496                         if (buf_offset > buf_length)
 497                                 buf_length = buf_offset;
 498
 499                         buf_dirty = true;
 500                 }
 501
 502                 public override int Read ([In,Out] byte[] array, int offset, int count)
 503                 {
 504                         if (safeHandle.IsClosed)
 505                                 throw new ObjectDisposedException ("Stream has been closed");
 506                         if (array == null)
 507                                 throw new ArgumentNullException ("array");
 508                         if (!CanRead)
 509                                 throw new NotSupportedException ("Stream does not support reading");
 510                         int len = array.Length;
 511                         if (offset < 0)
 512                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 513                         if (count < 0)
 514                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 515                         if (offset > len)
 516                                 throw new ArgumentException ("destination offset is beyond array size");
 517                         // reordered to avoid possible integer overflow
 518                         if (offset > len - count)
 519                                 throw new ArgumentException ("Reading would overrun buffer");
 520
 521                         if (async) {
 522                                 IAsyncResult ares = BeginRead (array, offset, count, null, null);
 523                                 return EndRead (ares);
 524                         }
 525
 526                         return ReadInternal (array, offset, count);
 527                 }
 528
 529                 int ReadInternal (byte [] dest, int offset, int count)
 530                 {
 531                         int n = ReadSegment (dest, offset, count);
 532                         if (n == count) {
 533                                 return count;
 534                         }
 535
 536                         int copied = n;
 537                         count -= n;
 538
 539                         if (count > buf_size) {
 540                                 /* Read as much as we can, up
 541                                  * to count bytes
 542                                  */
 543                                 FlushBuffer();
 544                                 n = ReadData (safeHandle, dest, offset+n, count);
 545
 546                                 /* Make the next buffer read
 547                                  * start from the right place
 548                                  */
 549                                 buf_start += n;
 550                         } else {
 551                                 RefillBuffer ();
 552                                 n = ReadSegment (dest, offset+copied, count);
 553                         }
 554
 555                         return copied + n;
 556                 }
 557
 558                 delegate int ReadDelegate (byte [] buffer, int offset, int count);
 559
 560                 public override IAsyncResult BeginRead (byte [] array, int offset, int numBytes,
 561                                                         AsyncCallback userCallback, object stateObject)
 562                 {
 563                         if (safeHandle.IsClosed)
 564                                 throw new ObjectDisposedException ("Stream has been closed");
 565
 566                         if (!CanRead)
 567                                 throw new NotSupportedException ("This stream does not support reading");
 568
 569                         if (array == null)
 570                                 throw new ArgumentNullException ("array");
 571
 572                         if (numBytes < 0)
 573                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 574
 575                         if (offset < 0)
 576                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 577
 578                         // reordered to avoid possible integer overflow
 579                         if (numBytes > array.Length - offset)
 580                                 throw new ArgumentException ("Buffer too small. numBytes/offset wrong.");
 581
 582                         if (!async)
 583                                 return base.BeginRead (array, offset, numBytes, userCallback, stateObject);
 584
 585                         ReadDelegate r = new ReadDelegate (ReadInternal);
 586                         return r.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 587                 }
 588
 589                 public override int EndRead (IAsyncResult asyncResult)
 590                 {
 591                         if (asyncResult == null)
 592                                 throw new ArgumentNullException ("asyncResult");
 593
 594                         if (!async)
 595                                 return base.EndRead (asyncResult);
 596
 597                         AsyncResult ares = asyncResult as AsyncResult;
 598                         if (ares == null)
 599                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 600
 601                         ReadDelegate r = ares.AsyncDelegate as ReadDelegate;
 602                         if (r == null)
 603                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 604
 605                         return r.EndInvoke (asyncResult);
 606                 }
 607
 608                 public override void Write (byte[] array, int offset, int count)
 609                 {
 610                         if (safeHandle.IsClosed)
 611                                 throw new ObjectDisposedException ("Stream has been closed");
 612                         if (array == null)
 613                                 throw new ArgumentNullException ("array");
 614                         if (offset < 0)
 615                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 616                         if (count < 0)
 617                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 618                         // ordered to avoid possible integer overflow
 619                         if (offset > array.Length - count)
 620                                 throw new ArgumentException ("Reading would overrun buffer");
 621                         if (!CanWrite)
 622                                 throw new NotSupportedException ("Stream does not support writing");
 623
 624                         if (async) {
 625                                 IAsyncResult ares = BeginWrite (array, offset, count, null, null);
 626                                 EndWrite (ares);
 627                                 return;
 628                         }
 629
 630                         WriteInternal (array, offset, count);
 631                 }
 632
 633                 void WriteInternal (byte [] src, int offset, int count)
 634                 {
 635                         if (count > buf_size) {
 636                                 // shortcut for long writes
 637                                 MonoIOError error;
 638
 639                                 FlushBuffer ();
 640                                 int wcount = count;
 641
 642                                 while (wcount > 0){
 643                                         int n = MonoIO.Write (safeHandle, src, offset, wcount, out error);
 644                                         if (error != MonoIOError.ERROR_SUCCESS)
 645                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 646
 647                                         wcount -= n;
 648                                         offset += n;
 649                                 }
 650                                 buf_start += count;
 651                         } else {
 652
 653                                 int copied = 0;
 654                                 while (count > 0) {
 655
 656                                         int n = WriteSegment (src, offset + copied, count);
 657                                         copied += n;
 658                                         count -= n;
 659
 660                                         if (count == 0) {
 661                                                 break;
 662                                         }
 663
 664                                         FlushBuffer ();
 665                                 }
 666                         }
 667                 }
 668
 669                 delegate void WriteDelegate (byte [] buffer, int offset, int count);
 670
 671                 public override IAsyncResult BeginWrite (byte [] array, int offset, int numBytes,
 672                                                         AsyncCallback userCallback, object stateObject)
 673                 {
 674                         if (safeHandle.IsClosed)
 675                                 throw new ObjectDisposedException ("Stream has been closed");
 676
 677                         if (!CanWrite)
 678                                 throw new NotSupportedException ("This stream does not support writing");
 679
 680                         if (array == null)
 681                                 throw new ArgumentNullException ("array");
 682
 683                         if (numBytes < 0)
 684                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 685
 686                         if (offset < 0)
 687                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 688
 689                         // reordered to avoid possible integer overflow
 690                         if (numBytes > array.Length - offset)
 691                                 throw new ArgumentException ("array too small. numBytes/offset wrong.");
 692
 693                         if (!async)
 694                                 return base.BeginWrite (array, offset, numBytes, userCallback, stateObject);
 695
 696                         FileStreamAsyncResult result = new FileStreamAsyncResult (userCallback, stateObject);
 697                         result.BytesRead = -1;
 698                         result.Count = numBytes;
 699                         result.OriginalCount = numBytes;
 700 /*
 701                         if (buf_dirty) {
 702                                 MemoryStream ms = new MemoryStream ();
 703                                 FlushBuffer (ms);
 704                                 ms.Write (array, offset, numBytes);
 705
 706                                 // Set arguments to new compounded buffer
 707                                 offset = 0;
 708                                 array = ms.ToArray ();
 709                                 numBytes = array.Length;
 710                         }
 711 */
 712                         WriteDelegate w = WriteInternal;
 713                         return w.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 714                 }
 715
 716                 public override void EndWrite (IAsyncResult asyncResult)
 717                 {
 718                         if (asyncResult == null)
 719                                 throw new ArgumentNullException ("asyncResult");
 720
 721                         if (!async) {
 722                                 base.EndWrite (asyncResult);
 723                                 return;
 724                         }
 725
 726                         AsyncResult ares = asyncResult as AsyncResult;
 727                         if (ares == null)
 728                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 729
 730                         WriteDelegate w = ares.AsyncDelegate as WriteDelegate;
 731                         if (w == null)
 732                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 733
 734                         w.EndInvoke (asyncResult);
 735                         return;
 736                 }
 737
 738                 public override long Seek (long offset, SeekOrigin origin)
 739                 {
 740                         long pos;
 741
 742                         if (safeHandle.IsClosed)
 743                                 throw new ObjectDisposedException ("Stream has been closed");
 744
 745                         // make absolute
 746
 747                         if(CanSeek == false) {
 748                                 throw new NotSupportedException("The stream does not support seeking");
 749                         }
 750
 751                         switch (origin) {
 752                         case SeekOrigin.End:
 753                                 pos = Length + offset;
 754                                 break;
 755
 756                         case SeekOrigin.Current:
 757                                 pos = Position + offset;
 758                                 break;
 759
 760                         case SeekOrigin.Begin:
 761                                 pos = offset;
 762                                 break;
 763
 764                         default:
 765                                 throw new ArgumentException ("origin", "Invalid SeekOrigin");
 766                         }
 767
 768                         if (pos < 0) {
 769                                 /* LAMESPEC: shouldn't this be
 770                                  * ArgumentOutOfRangeException?
 771                                  */
 772                                 throw new IOException("Attempted to Seek before the beginning of the stream");
 773                         }
 774
 775                         if(pos < this.append_startpos) {
 776                                 /* More undocumented crap */
 777                                 throw new IOException("Can't seek back over pre-existing data in append mode");
 778                         }
 779
 780                         FlushBuffer ();
 781
 782                         MonoIOError error;
 783
 784                         buf_start = MonoIO.Seek (safeHandle, pos, SeekOrigin.Begin, out error);
 785
 786                         if (error != MonoIOError.ERROR_SUCCESS) {
 787                                 // don't leak the path information for isolated storage
 788                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 789                         }
 790
 791                         return(buf_start);
 792                 }
 793
 794                 public override void SetLength (long value)
 795                 {
 796                         if (safeHandle.IsClosed)
 797                                 throw new ObjectDisposedException ("Stream has been closed");
 798
 799                         if(CanSeek == false)
 800                                 throw new NotSupportedException("The stream does not support seeking");
 801
 802                         if(CanWrite == false)
 803                                 throw new NotSupportedException("The stream does not support writing");
 804
 805                         if(value < 0)
 806                                 throw new ArgumentOutOfRangeException("value is less than 0");
 807
 808                         FlushBuffer ();
 809
 810                         MonoIOError error;
 811
 812                         MonoIO.SetLength (safeHandle, value, out error);
 813                         if (error != MonoIOError.ERROR_SUCCESS) {
 814                                 // don't leak the path information for isolated storage
 815                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 816                         }
 817
 818                         if (Position > value)
 819                                 Position = value;
 820                 }
 821
 822                 public override void Flush ()
 823                 {
 824                         if (safeHandle.IsClosed)
 825                                 throw new ObjectDisposedException ("Stream has been closed");
 826
 827                         FlushBuffer ();
 828                 }
 829
 830                 public virtual void Flush (bool flushToDisk)
 831                 {
 832                         if (safeHandle.IsClosed)
 833                                 throw new ObjectDisposedException ("Stream has been closed");
 834
 835                         FlushBuffer ();
 836
 837                         // This does the fsync
 838                         if (flushToDisk){
 839                                 MonoIOError error;
 840                                 MonoIO.Flush (safeHandle, out error);
 841                         }
 842                 }
 843
 844                 public virtual void Lock (long position, long length)
 845                 {
 846                         if (safeHandle.IsClosed)
 847                                 throw new ObjectDisposedException ("Stream has been closed");
 848                         if (position < 0) {
 849                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 850                         }
 851                         if (length < 0) {
 852                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 853                         }
 854
 855                         MonoIOError error;
 856
 857                         MonoIO.Lock (safeHandle, position, length, out error);
 858                         if (error != MonoIOError.ERROR_SUCCESS) {
 859                                 // don't leak the path information for isolated storage
 860                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 861                         }
 862                 }
 863
 864                 public virtual void Unlock (long position, long length)
 865                 {
 866                         if (safeHandle.IsClosed)
 867                                 throw new ObjectDisposedException ("Stream has been closed");
 868                         if (position < 0) {
 869                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 870                         }
 871                         if (length < 0) {
 872                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 873                         }
 874
 875                         MonoIOError error;
 876
 877                         MonoIO.Unlock (safeHandle, position, length, out error);
 878                         if (error != MonoIOError.ERROR_SUCCESS) {
 879                                 // don't leak the path information for isolated storage
 880                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 881                         }
 882                 }
 883
 884                 // protected
 885
 886                 ~FileStream ()
 887                 {
 888                         Dispose (false);
 889                 }
 890
 891                 protected override void Dispose (bool disposing)
 892                 {
 893                         Exception exc = null;
 894                         if (safeHandle != null && !safeHandle.IsClosed) {
 895                                 try {
 896                                         // If the FileStream is in "exposed" status
 897                                         // it means that we do not have a buffer(we write the data without buffering)
 898                                         // therefor we don't and can't flush the buffer becouse we don't have one.
 899                                         FlushBuffer ();
 900                                 } catch (Exception e) {
 901                                         exc = e;
 902                                 }
 903
 904                                 if (owner) {
 905                                         MonoIOError error;
 906
 907                                         MonoIO.Close (safeHandle.DangerousGetHandle (), out error);
 908                                         if (error != MonoIOError.ERROR_SUCCESS) {
 909                                                 // don't leak the path information for isolated storage
 910                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 911                                         }
 912
 913                                         safeHandle.DangerousRelease ();
 914                                 }
 915                         }
 916
 917                         canseek = false;
 918                         access = 0;
 919
 920                         if (disposing && buf != null) {
 921                                 if (buf.Length == DefaultBufferSize && buf_recycle == null) {
 922                                         lock (buf_recycle_lock) {
 923                                                 if (buf_recycle == null) {
 924                                                         buf_recycle = buf;
 925                                                 }
 926                                         }
 927                                 }
 928
 929                                 buf = null;
 930                                 GC.SuppressFinalize (this);
 931                         }
 932                         if (exc != null)
 933                                 throw exc;
 934                 }
 935
 936 #if !NET_2_1
 937                 public FileSecurity GetAccessControl ()
 938                 {
 939                         if (safeHandle.IsClosed)
 940                                 throw new ObjectDisposedException ("Stream has been closed");
 941
 942                         return new FileSecurity (SafeFileHandle,
 943                                                  AccessControlSections.Owner |
 944                                                  AccessControlSections.Group |
 945                                                  AccessControlSections.Access);
 946                 }
 947
 948                 public void SetAccessControl (FileSecurity fileSecurity)
 949                 {
 950                         if (safeHandle.IsClosed)
 951                                 throw new ObjectDisposedException ("Stream has been closed");
 952
 953                         if (null == fileSecurity)
 954                                 throw new ArgumentNullException ("fileSecurity");
 955
 956                         fileSecurity.PersistModifications (SafeFileHandle);
 957                 }
 958 #endif
 959
 960                 public override Task FlushAsync (CancellationToken cancellationToken)
 961                 {
 962                         if (safeHandle.IsClosed)
 963                                 throw new ObjectDisposedException ("Stream has been closed");
 964
 965                         return base.FlushAsync (cancellationToken);
 966                 }
 967
 968                 public override Task<int> ReadAsync (byte[] buffer, int offset, int count, CancellationToken cancellationToken)
 969                 {
 970                         return base.ReadAsync (buffer, offset, count, cancellationToken);
 971                 }
 972
 973                 public override Task WriteAsync (byte[] buffer, int offset, int count, CancellationToken cancellationToken)
 974                 {
 975                         return base.WriteAsync (buffer, offset, count, cancellationToken);
 976                 }
 977
 978                 // private.
 979
 980                 // ReadSegment, WriteSegment, FlushBuffer,
 981                 // RefillBuffer and ReadData should only be called
 982                 // when the Monitor lock is held, but these methods
 983                 // grab it again just to be safe.
 984
 985                 private int ReadSegment (byte [] dest, int dest_offset, int count)
 986                 {
 987                         count = Math.Min (count, buf_length - buf_offset);
 988
 989                         if (count > 0) {
 990                                 // Use the fastest method, all range checks has been done
 991                                 Buffer.BlockCopyInternal (buf, buf_offset, dest, dest_offset, count);
 992                                 buf_offset += count;
 993                         }
 994
 995                         return count;
 996                 }
 997
 998                 private int WriteSegment (byte [] src, int src_offset,
 999                                           int count)
1000                 {
1001                         if (count > buf_size - buf_offset) {
1002                                 count = buf_size - buf_offset;
1003                         }
1004
1005                         if (count > 0) {
1006                                 Buffer.BlockCopy (src, src_offset,
1007                                                   buf, buf_offset,
1008                                                   count);
1009                                 buf_offset += count;
1010                                 if (buf_offset > buf_length) {
1011                                         buf_length = buf_offset;
1012                                 }
1013
1014                                 buf_dirty = true;
1015                         }
1016
1017                         return(count);
1018                 }
1019
1020                 void FlushBuffer ()
1021                 {
1022                         if (buf_dirty) {
1023 //                              if (st == null) {
1024                                         MonoIOError error;
1025
1026                                         if (CanSeek == true && !isExposed) {
1027                                                 MonoIO.Seek (safeHandle, buf_start, SeekOrigin.Begin, out error);
1028
1029                                                 if (error != MonoIOError.ERROR_SUCCESS) {
1030                                                         // don't leak the path information for isolated storage
1031                                                         throw MonoIO.GetException (GetSecureFileName (name), error);
1032                                                 }
1033                                         }
1034
1035                                         int wcount = buf_length;
1036                                         int offset = 0;
1037                                         while (wcount > 0){
1038                                                 int n = MonoIO.Write (safeHandle, buf, 0, buf_length, out error);
1039                                                 if (error != MonoIOError.ERROR_SUCCESS) {
1040                                                         // don't leak the path information for isolated storage
1041                                                         throw MonoIO.GetException (GetSecureFileName (name), error);
1042                                                 }
1043                                                 wcount -= n;
1044                                                 offset += n;
1045                                         }
1046 //                              } else {
1047 //                                      st.Write (buf, 0, buf_length);
1048 //                              }
1049                         }
1050
1051                         buf_start += buf_offset;
1052                         buf_offset = buf_length = 0;
1053                         buf_dirty = false;
1054                 }
1055
1056                 private void FlushBufferIfDirty ()
1057                 {
1058                         if (buf_dirty)
1059                                 FlushBuffer ();
1060                 }
1061
1062                 private void RefillBuffer ()
1063                 {
1064                         FlushBuffer ();
1065
1066                         buf_length = ReadData (safeHandle, buf, 0, buf_size);
1067                 }
1068
1069                 private int ReadData (SafeHandle safeHandle, byte[] buf, int offset,
1070                                       int count)
1071                 {
1072                         MonoIOError error;
1073                         int amount = 0;
1074
1075                         /* when async == true, if we get here we don't suport AIO or it's disabled
1076                          * and we're using the threadpool */
1077                         amount = MonoIO.Read (safeHandle, buf, offset, count, out error);
1078                         if (error == MonoIOError.ERROR_BROKEN_PIPE) {
1079                                 amount = 0; // might not be needed, but well...
1080                         } else if (error != MonoIOError.ERROR_SUCCESS) {
1081                                 // don't leak the path information for isolated storage
1082                                 throw MonoIO.GetException (GetSecureFileName (name), error);
1083                         }
1084
1085                         /* Check for read error */
1086                         if(amount == -1) {
1087                                 throw new IOException ();
1088                         }
1089
1090                         return(amount);
1091                 }
1092
1093                 void InitBuffer (int size, bool isZeroSize)
1094                 {
1095                         if (isZeroSize) {
1096                                 size = 0;
1097                                 buf = new byte[1];
1098                         } else {
1099                                 if (size <= 0)
1100                                         throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
1101
1102                                 size = Math.Max (size, 8);
1103
1104                                 //
1105                                 // Instead of allocating a new default buffer use the
1106                                 // last one if there is any available
1107                                 //
1108                                 if (size <= DefaultBufferSize && buf_recycle != null) {
1109                                         lock (buf_recycle_lock) {
1110                                                 if (buf_recycle != null) {
1111                                                         buf = buf_recycle;
1112                                                         buf_recycle = null;
1113                                                 }
1114                                         }
1115                                 }
1116
1117                                 if (buf == null)
1118                                         buf = new byte [size];
1119                                 else
1120                                         Array.Clear (buf, 0, size);
1121                         }
1122
1123                         buf_size = size;
1124 //                      buf_start = 0;
1125 //                      buf_offset = buf_length = 0;
1126 //                      buf_dirty = false;
1127                 }
1128
1129                 private string GetSecureFileName (string filename)
1130                 {
1131                         return (anonymous) ? Path.GetFileName (filename) : Path.GetFullPath (filename);
1132                 }
1133
1134                 private string GetSecureFileName (string filename, bool full)
1135                 {
1136                         return (anonymous) ? Path.GetFileName (filename) :
1137                                 (full) ? Path.GetFullPath (filename) : filename;
1138                 }
1139
1140                 // fields
1141
1142                 internal const int DefaultBufferSize = 4096;
1143
1144                 // Input buffer ready for recycling
1145                 static byte[] buf_recycle;
1146                 static readonly object buf_recycle_lock = new object ();
1147
1148                 private byte [] buf;                    // the buffer
1149                 private string name = "[Unknown]";      // name of file.
1150
1151                 private SafeFileHandle safeHandle;
1152                 private bool isExposed;
1153
1154                 private long append_startpos;
1155
1156                 private FileAccess access;
1157                 private bool owner;
1158                 private bool async;
1159                 private bool canseek;
1160                 private bool anonymous;
1161                 private bool buf_dirty;                 // true if buffer has been written to
1162
1163                 private int buf_size;                   // capacity in bytes
1164                 private int buf_length;                 // number of valid bytes in buffer
1165                 private int buf_offset;                 // position of next byte
1166                 private long buf_start;                 // location of buffer in file
1167         }
1168 }