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 isConsoleWrapper)
  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, isConsoleWrapper);
  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                 public FileStream (SafeFileHandle handle, FileAccess access)
 117                         :this(handle, access, DefaultBufferSize, false)
 118                 {
 119                 }
 120
 121                 public FileStream (SafeFileHandle handle, FileAccess access,
 122                                    int bufferSize)
 123                         :this(handle, access, bufferSize, false)
 124                 {
 125                 }
 126
 127                 public FileStream (SafeFileHandle handle, FileAccess access, int bufferSize, bool isAsync)
 128                 {
 129                         Init (handle, access, false, bufferSize, isAsync, false);
 130                 }
 131
 132 #if !MOBILE
 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 = false, bool checkHost = false)
 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 isConsoleWrapper)
 295                 {
 296                         if (!isConsoleWrapper && safeHandle.IsInvalid)
 297                                 throw new ArgumentException(Environment.GetResourceString("Arg_InvalidHandle"), "handle");
 298                         if (access < FileAccess.Read || access > FileAccess.ReadWrite)
 299                                 throw new ArgumentOutOfRangeException ("access");
 300                         if (!isConsoleWrapper && bufferSize <= 0)
 301                                 throw new ArgumentOutOfRangeException("bufferSize", Environment.GetResourceString("ArgumentOutOfRange_NeedPosNum"));
 302
 303                         MonoIOError error;
 304                         MonoFileType ftype = MonoIO.GetFileType (safeHandle, out error);
 305
 306                         if (error != MonoIOError.ERROR_SUCCESS) {
 307                                 throw MonoIO.GetException (name, error);
 308                         }
 309
 310                         if (ftype == MonoFileType.Unknown) {
 311                                 throw new IOException ("Invalid handle.");
 312                         } else if (ftype == MonoFileType.Disk) {
 313                                 this.canseek = true;
 314                         } else {
 315                                 this.canseek = false;
 316                         }
 317
 318                         this.safeHandle = safeHandle;
 319                         ExposeHandle ();
 320                         this.access = access;
 321                         this.owner = ownsHandle;
 322                         this.async = isAsync;
 323                         this.anonymous = false;
 324
 325                         if (canseek) {
 326                                 buf_start = MonoIO.Seek (safeHandle, 0, SeekOrigin.Current, out error);
 327                                 if (error != MonoIOError.ERROR_SUCCESS) {
 328                                         throw MonoIO.GetException (name, error);
 329                                 }
 330                         }
 331
 332                         /* Can't set append mode */
 333                         this.append_startpos=0;
 334                 }
 335
 336                 // properties
 337
 338                 public override bool CanRead {
 339                         get {
 340                                 return access == FileAccess.Read ||
 341                                        access == FileAccess.ReadWrite;
 342                         }
 343                 }
 344
 345                 public override bool CanWrite {
 346                         get {
 347                                 return access == FileAccess.Write ||
 348                                         access == FileAccess.ReadWrite;
 349                         }
 350                 }
 351
 352                 public override bool CanSeek {
 353                         get {
 354                                 return(canseek);
 355                         }
 356                 }
 357
 358                 public virtual bool IsAsync {
 359                         get {
 360                                 return (async);
 361                         }
 362                 }
 363
 364                 public string Name {
 365                         get {
 366                                 return name;
 367                         }
 368                 }
 369
 370                 public override long Length {
 371                         get {
 372                                 if (safeHandle.IsClosed)
 373                                         throw new ObjectDisposedException ("Stream has been closed");
 374
 375                                 if (!CanSeek)
 376                                         throw new NotSupportedException ("The stream does not support seeking");
 377
 378                                 // Buffered data might change the length of the stream
 379                                 FlushBufferIfDirty ();
 380
 381                                 MonoIOError error;
 382
 383                                 long length = MonoIO.GetLength (safeHandle, out error);
 384
 385                                 if (error != MonoIOError.ERROR_SUCCESS) {
 386                                         // don't leak the path information for isolated storage
 387                                         throw MonoIO.GetException (GetSecureFileName (name), error);
 388                                 }
 389
 390                                 return(length);
 391                         }
 392                 }
 393
 394                 public override long Position {
 395                         get {
 396                                 if (safeHandle.IsClosed)
 397                                         throw new ObjectDisposedException ("Stream has been closed");
 398
 399                                 if (CanSeek == false)
 400                                         throw new NotSupportedException("The stream does not support seeking");
 401
 402                                 if (!isExposed)
 403                                         return(buf_start + buf_offset);
 404
 405                                 // If the handle was leaked outside we always ask the real handle
 406                                 MonoIOError error;
 407
 408                                 long ret = MonoIO.Seek (safeHandle, 0, SeekOrigin.Current, out error);
 409
 410                                 if (error != MonoIOError.ERROR_SUCCESS) {
 411                                         // don't leak the path information for isolated storage
 412                                         throw MonoIO.GetException (GetSecureFileName (name), error);
 413                                 }
 414
 415                                 return ret;
 416                         }
 417                         set {
 418                                 if (value < 0) throw new ArgumentOutOfRangeException("value", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
 419
 420                                 Seek (value, SeekOrigin.Begin);
 421                         }
 422                 }
 423
 424                 [Obsolete ("Use SafeFileHandle instead")]
 425                 public virtual IntPtr Handle {
 426                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 427                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 428                         get {
 429                                 var handle = safeHandle.DangerousGetHandle ();
 430                                 if (!isExposed)
 431                                         ExposeHandle ();
 432                                 return handle;
 433                         }
 434                 }
 435
 436                 public virtual SafeFileHandle SafeFileHandle {
 437                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 438                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 439                         get {
 440                                 if (!isExposed)
 441                                         ExposeHandle ();
 442                                 return safeHandle;
 443                         }
 444                 }
 445
 446                 void ExposeHandle ()
 447                 {
 448                         isExposed = true;
 449                         FlushBuffer ();
 450                         InitBuffer (0, true);
 451                 }
 452
 453                 // methods
 454
 455                 public override int ReadByte ()
 456                 {
 457                         if (safeHandle.IsClosed)
 458                                 throw new ObjectDisposedException ("Stream has been closed");
 459
 460                         if (!CanRead)
 461                                 throw new NotSupportedException ("Stream does not support reading");
 462
 463                         if (buf_size == 0) {
 464                                 int n = ReadData (safeHandle, buf, 0, 1);
 465                                 if (n == 0) return -1;
 466                                 else return buf[0];
 467                         }
 468                         else if (buf_offset >= buf_length) {
 469                                 RefillBuffer ();
 470
 471                                 if (buf_length == 0)
 472                                         return -1;
 473                         }
 474
 475                         return buf [buf_offset ++];
 476                 }
 477
 478                 public override void WriteByte (byte value)
 479                 {
 480                         if (safeHandle.IsClosed)
 481                                 throw new ObjectDisposedException ("Stream has been closed");
 482
 483                         if (!CanWrite)
 484                                 throw new NotSupportedException ("Stream does not support writing");
 485
 486                         if (buf_offset == buf_size)
 487                                 FlushBuffer ();
 488
 489                         if (buf_size == 0) { // No buffering
 490                                 buf [0] = value;
 491                                 buf_dirty = true;
 492                                 buf_length = 1;
 493                                 FlushBuffer ();
 494                                 return;
 495                         }
 496
 497                         buf [buf_offset ++] = value;
 498                         if (buf_offset > buf_length)
 499                                 buf_length = buf_offset;
 500
 501                         buf_dirty = true;
 502                 }
 503
 504                 public override int Read ([In,Out] byte[] array, int offset, int count)
 505                 {
 506                         if (safeHandle.IsClosed)
 507                                 throw new ObjectDisposedException ("Stream has been closed");
 508                         if (array == null)
 509                                 throw new ArgumentNullException ("array");
 510                         if (!CanRead)
 511                                 throw new NotSupportedException ("Stream does not support reading");
 512                         int len = array.Length;
 513                         if (offset < 0)
 514                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 515                         if (count < 0)
 516                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 517                         if (offset > len)
 518                                 throw new ArgumentException ("destination offset is beyond array size");
 519                         // reordered to avoid possible integer overflow
 520                         if (offset > len - count)
 521                                 throw new ArgumentException ("Reading would overrun buffer");
 522
 523                         if (async) {
 524                                 IAsyncResult ares = BeginRead (array, offset, count, null, null);
 525                                 return EndRead (ares);
 526                         }
 527
 528                         return ReadInternal (array, offset, count);
 529                 }
 530
 531                 int ReadInternal (byte [] dest, int offset, int count)
 532                 {
 533                         int n = ReadSegment (dest, offset, count);
 534                         if (n == count) {
 535                                 return count;
 536                         }
 537
 538                         int copied = n;
 539                         count -= n;
 540
 541                         if (count > buf_size) {
 542                                 /* Read as much as we can, up
 543                                  * to count bytes
 544                                  */
 545                                 FlushBuffer();
 546                                 n = ReadData (safeHandle, dest, offset+n, count);
 547
 548                                 /* Make the next buffer read
 549                                  * start from the right place
 550                                  */
 551                                 buf_start += n;
 552                         } else {
 553                                 RefillBuffer ();
 554                                 n = ReadSegment (dest, offset+copied, count);
 555                         }
 556
 557                         return copied + n;
 558                 }
 559
 560                 delegate int ReadDelegate (byte [] buffer, int offset, int count);
 561
 562                 public override IAsyncResult BeginRead (byte [] array, int offset, int numBytes,
 563                                                         AsyncCallback userCallback, object stateObject)
 564                 {
 565                         if (safeHandle.IsClosed)
 566                                 throw new ObjectDisposedException ("Stream has been closed");
 567
 568                         if (!CanRead)
 569                                 throw new NotSupportedException ("This stream does not support reading");
 570
 571                         if (array == null)
 572                                 throw new ArgumentNullException ("array");
 573
 574                         if (numBytes < 0)
 575                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 576
 577                         if (offset < 0)
 578                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 579
 580                         // reordered to avoid possible integer overflow
 581                         if (numBytes > array.Length - offset)
 582                                 throw new ArgumentException ("Buffer too small. numBytes/offset wrong.");
 583
 584                         if (!async)
 585                                 return base.BeginRead (array, offset, numBytes, userCallback, stateObject);
 586
 587                         ReadDelegate r = new ReadDelegate (ReadInternal);
 588                         return r.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 589                 }
 590
 591                 public override int EndRead (IAsyncResult asyncResult)
 592                 {
 593                         if (asyncResult == null)
 594                                 throw new ArgumentNullException ("asyncResult");
 595
 596                         if (!async)
 597                                 return base.EndRead (asyncResult);
 598
 599                         AsyncResult ares = asyncResult as AsyncResult;
 600                         if (ares == null)
 601                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 602
 603                         ReadDelegate r = ares.AsyncDelegate as ReadDelegate;
 604                         if (r == null)
 605                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 606
 607                         return r.EndInvoke (asyncResult);
 608                 }
 609
 610                 public override void Write (byte[] array, int offset, int count)
 611                 {
 612                         if (safeHandle.IsClosed)
 613                                 throw new ObjectDisposedException ("Stream has been closed");
 614                         if (array == null)
 615                                 throw new ArgumentNullException ("array");
 616                         if (offset < 0)
 617                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 618                         if (count < 0)
 619                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 620                         // ordered to avoid possible integer overflow
 621                         if (offset > array.Length - count)
 622                                 throw new ArgumentException ("Reading would overrun buffer");
 623                         if (!CanWrite)
 624                                 throw new NotSupportedException ("Stream does not support writing");
 625
 626                         if (async) {
 627                                 IAsyncResult ares = BeginWrite (array, offset, count, null, null);
 628                                 EndWrite (ares);
 629                                 return;
 630                         }
 631
 632                         WriteInternal (array, offset, count);
 633                 }
 634
 635                 void WriteInternal (byte [] src, int offset, int count)
 636                 {
 637                         if (count > buf_size) {
 638                                 // shortcut for long writes
 639                                 MonoIOError error;
 640
 641                                 FlushBuffer ();
 642                                 int wcount = count;
 643
 644                                 while (wcount > 0){
 645                                         int n = MonoIO.Write (safeHandle, src, offset, wcount, out error);
 646                                         if (error != MonoIOError.ERROR_SUCCESS)
 647                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 648
 649                                         wcount -= n;
 650                                         offset += n;
 651                                 }
 652                                 buf_start += count;
 653                         } else {
 654
 655                                 int copied = 0;
 656                                 while (count > 0) {
 657
 658                                         int n = WriteSegment (src, offset + copied, count);
 659                                         copied += n;
 660                                         count -= n;
 661
 662                                         if (count == 0) {
 663                                                 break;
 664                                         }
 665
 666                                         FlushBuffer ();
 667                                 }
 668                         }
 669                 }
 670
 671                 delegate void WriteDelegate (byte [] buffer, int offset, int count);
 672
 673                 public override IAsyncResult BeginWrite (byte [] array, int offset, int numBytes,
 674                                                         AsyncCallback userCallback, object stateObject)
 675                 {
 676                         if (safeHandle.IsClosed)
 677                                 throw new ObjectDisposedException ("Stream has been closed");
 678
 679                         if (!CanWrite)
 680                                 throw new NotSupportedException ("This stream does not support writing");
 681
 682                         if (array == null)
 683                                 throw new ArgumentNullException ("array");
 684
 685                         if (numBytes < 0)
 686                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 687
 688                         if (offset < 0)
 689                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 690
 691                         // reordered to avoid possible integer overflow
 692                         if (numBytes > array.Length - offset)
 693                                 throw new ArgumentException ("array too small. numBytes/offset wrong.");
 694
 695                         if (!async)
 696                                 return base.BeginWrite (array, offset, numBytes, userCallback, stateObject);
 697
 698                         FileStreamAsyncResult result = new FileStreamAsyncResult (userCallback, stateObject);
 699                         result.BytesRead = -1;
 700                         result.Count = numBytes;
 701                         result.OriginalCount = numBytes;
 702 /*
 703                         if (buf_dirty) {
 704                                 MemoryStream ms = new MemoryStream ();
 705                                 FlushBuffer (ms);
 706                                 ms.Write (array, offset, numBytes);
 707
 708                                 // Set arguments to new compounded buffer
 709                                 offset = 0;
 710                                 array = ms.ToArray ();
 711                                 numBytes = array.Length;
 712                         }
 713 */
 714                         WriteDelegate w = WriteInternal;
 715                         return w.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 716                 }
 717
 718                 public override void EndWrite (IAsyncResult asyncResult)
 719                 {
 720                         if (asyncResult == null)
 721                                 throw new ArgumentNullException ("asyncResult");
 722
 723                         if (!async) {
 724                                 base.EndWrite (asyncResult);
 725                                 return;
 726                         }
 727
 728                         AsyncResult ares = asyncResult as AsyncResult;
 729                         if (ares == null)
 730                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 731
 732                         WriteDelegate w = ares.AsyncDelegate as WriteDelegate;
 733                         if (w == null)
 734                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 735
 736                         w.EndInvoke (asyncResult);
 737                         return;
 738                 }
 739
 740                 public override long Seek (long offset, SeekOrigin origin)
 741                 {
 742                         long pos;
 743
 744                         if (safeHandle.IsClosed)
 745                                 throw new ObjectDisposedException ("Stream has been closed");
 746
 747                         // make absolute
 748
 749                         if(CanSeek == false) {
 750                                 throw new NotSupportedException("The stream does not support seeking");
 751                         }
 752
 753                         switch (origin) {
 754                         case SeekOrigin.End:
 755                                 pos = Length + offset;
 756                                 break;
 757
 758                         case SeekOrigin.Current:
 759                                 pos = Position + offset;
 760                                 break;
 761
 762                         case SeekOrigin.Begin:
 763                                 pos = offset;
 764                                 break;
 765
 766                         default:
 767                                 throw new ArgumentException ("origin", "Invalid SeekOrigin");
 768                         }
 769
 770                         if (pos < 0) {
 771                                 /* LAMESPEC: shouldn't this be
 772                                  * ArgumentOutOfRangeException?
 773                                  */
 774                                 throw new IOException("Attempted to Seek before the beginning of the stream");
 775                         }
 776
 777                         if(pos < this.append_startpos) {
 778                                 /* More undocumented crap */
 779                                 throw new IOException("Can't seek back over pre-existing data in append mode");
 780                         }
 781
 782                         FlushBuffer ();
 783
 784                         MonoIOError error;
 785
 786                         buf_start = MonoIO.Seek (safeHandle, pos, SeekOrigin.Begin, out error);
 787
 788                         if (error != MonoIOError.ERROR_SUCCESS) {
 789                                 // don't leak the path information for isolated storage
 790                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 791                         }
 792
 793                         return(buf_start);
 794                 }
 795
 796                 public override void SetLength (long value)
 797                 {
 798                         if (safeHandle.IsClosed)
 799                                 throw new ObjectDisposedException ("Stream has been closed");
 800
 801                         if(CanSeek == false)
 802                                 throw new NotSupportedException("The stream does not support seeking");
 803
 804                         if(CanWrite == false)
 805                                 throw new NotSupportedException("The stream does not support writing");
 806
 807                         if(value < 0)
 808                                 throw new ArgumentOutOfRangeException("value is less than 0");
 809
 810                         FlushBuffer ();
 811
 812                         MonoIOError error;
 813
 814                         MonoIO.SetLength (safeHandle, value, out error);
 815                         if (error != MonoIOError.ERROR_SUCCESS) {
 816                                 // don't leak the path information for isolated storage
 817                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 818                         }
 819
 820                         if (Position > value)
 821                                 Position = value;
 822                 }
 823
 824                 public override void Flush ()
 825                 {
 826                         if (safeHandle.IsClosed)
 827                                 throw new ObjectDisposedException ("Stream has been closed");
 828
 829                         FlushBuffer ();
 830                 }
 831
 832                 public virtual void Flush (bool flushToDisk)
 833                 {
 834                         if (safeHandle.IsClosed)
 835                                 throw new ObjectDisposedException ("Stream has been closed");
 836
 837                         FlushBuffer ();
 838
 839                         // This does the fsync
 840                         if (flushToDisk){
 841                                 MonoIOError error;
 842                                 MonoIO.Flush (safeHandle, out error);
 843                         }
 844                 }
 845
 846                 public virtual void Lock (long position, long length)
 847                 {
 848                         if (safeHandle.IsClosed)
 849                                 throw new ObjectDisposedException ("Stream has been closed");
 850                         if (position < 0) {
 851                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 852                         }
 853                         if (length < 0) {
 854                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 855                         }
 856
 857                         MonoIOError error;
 858
 859                         MonoIO.Lock (safeHandle, position, length, out error);
 860                         if (error != MonoIOError.ERROR_SUCCESS) {
 861                                 // don't leak the path information for isolated storage
 862                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 863                         }
 864                 }
 865
 866                 public virtual void Unlock (long position, long length)
 867                 {
 868                         if (safeHandle.IsClosed)
 869                                 throw new ObjectDisposedException ("Stream has been closed");
 870                         if (position < 0) {
 871                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 872                         }
 873                         if (length < 0) {
 874                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 875                         }
 876
 877                         MonoIOError error;
 878
 879                         MonoIO.Unlock (safeHandle, position, length, out error);
 880                         if (error != MonoIOError.ERROR_SUCCESS) {
 881                                 // don't leak the path information for isolated storage
 882                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 883                         }
 884                 }
 885
 886                 // protected
 887
 888                 ~FileStream ()
 889                 {
 890                         Dispose (false);
 891                 }
 892
 893                 protected override void Dispose (bool disposing)
 894                 {
 895                         Exception exc = null;
 896                         if (safeHandle != null && !safeHandle.IsClosed) {
 897                                 try {
 898                                         // If the FileStream is in "exposed" status
 899                                         // it means that we do not have a buffer(we write the data without buffering)
 900                                         // therefor we don't and can't flush the buffer becouse we don't have one.
 901                                         FlushBuffer ();
 902                                 } catch (Exception e) {
 903                                         exc = e;
 904                                 }
 905
 906                                 if (owner) {
 907                                         MonoIOError error;
 908
 909                                         MonoIO.Close (safeHandle.DangerousGetHandle (), out error);
 910                                         if (error != MonoIOError.ERROR_SUCCESS) {
 911                                                 // don't leak the path information for isolated storage
 912                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 913                                         }
 914
 915                                         safeHandle.DangerousRelease ();
 916                                 }
 917                         }
 918
 919                         canseek = false;
 920                         access = 0;
 921
 922                         if (disposing && buf != null) {
 923                                 if (buf.Length == DefaultBufferSize && buf_recycle == null) {
 924                                         lock (buf_recycle_lock) {
 925                                                 if (buf_recycle == null) {
 926                                                         buf_recycle = buf;
 927                                                 }
 928                                         }
 929                                 }
 930
 931                                 buf = null;
 932                                 GC.SuppressFinalize (this);
 933                         }
 934                         if (exc != null)
 935                                 throw exc;
 936                 }
 937
 938 #if !NET_2_1
 939                 public FileSecurity GetAccessControl ()
 940                 {
 941                         if (safeHandle.IsClosed)
 942                                 throw new ObjectDisposedException ("Stream has been closed");
 943
 944                         return new FileSecurity (SafeFileHandle,
 945                                                  AccessControlSections.Owner |
 946                                                  AccessControlSections.Group |
 947                                                  AccessControlSections.Access);
 948                 }
 949
 950                 public void SetAccessControl (FileSecurity fileSecurity)
 951                 {
 952                         if (safeHandle.IsClosed)
 953                                 throw new ObjectDisposedException ("Stream has been closed");
 954
 955                         if (null == fileSecurity)
 956                                 throw new ArgumentNullException ("fileSecurity");
 957
 958                         fileSecurity.PersistModifications (SafeFileHandle);
 959                 }
 960 #endif
 961
 962                 public override Task FlushAsync (CancellationToken cancellationToken)
 963                 {
 964                         if (safeHandle.IsClosed)
 965                                 throw new ObjectDisposedException ("Stream has been closed");
 966
 967                         return base.FlushAsync (cancellationToken);
 968                 }
 969
 970                 public override Task<int> ReadAsync (byte[] buffer, int offset, int count, CancellationToken cancellationToken)
 971                 {
 972                         return base.ReadAsync (buffer, offset, count, cancellationToken);
 973                 }
 974
 975                 public override Task WriteAsync (byte[] buffer, int offset, int count, CancellationToken cancellationToken)
 976                 {
 977                         return base.WriteAsync (buffer, offset, count, cancellationToken);
 978                 }
 979
 980                 // private.
 981
 982                 // ReadSegment, WriteSegment, FlushBuffer,
 983                 // RefillBuffer and ReadData should only be called
 984                 // when the Monitor lock is held, but these methods
 985                 // grab it again just to be safe.
 986
 987                 private int ReadSegment (byte [] dest, int dest_offset, int count)
 988                 {
 989                         count = Math.Min (count, buf_length - buf_offset);
 990
 991                         if (count > 0) {
 992                                 // Use the fastest method, all range checks has been done
 993                                 Buffer.InternalBlockCopy (buf, buf_offset, dest, dest_offset, count);
 994                                 buf_offset += count;
 995                         }
 996
 997                         return count;
 998                 }
 999
1000                 private int WriteSegment (byte [] src, int src_offset,
1001                                           int count)
1002                 {
1003                         if (count > buf_size - buf_offset) {
1004                                 count = buf_size - buf_offset;
1005                         }
1006
1007                         if (count > 0) {
1008                                 Buffer.BlockCopy (src, src_offset,
1009                                                   buf, buf_offset,
1010                                                   count);
1011                                 buf_offset += count;
1012                                 if (buf_offset > buf_length) {
1013                                         buf_length = buf_offset;
1014                                 }
1015
1016                                 buf_dirty = true;
1017                         }
1018
1019                         return(count);
1020                 }
1021
1022                 void FlushBuffer ()
1023                 {
1024                         if (buf_dirty) {
1025 //                              if (st == null) {
1026                                         MonoIOError error;
1027
1028                                         if (CanSeek == true && !isExposed) {
1029                                                 MonoIO.Seek (safeHandle, buf_start, SeekOrigin.Begin, out error);
1030
1031                                                 if (error != MonoIOError.ERROR_SUCCESS) {
1032                                                         // don't leak the path information for isolated storage
1033                                                         throw MonoIO.GetException (GetSecureFileName (name), error);
1034                                                 }
1035                                         }
1036
1037                                         int wcount = buf_length;
1038                                         int offset = 0;
1039                                         while (wcount > 0){
1040                                                 int n = MonoIO.Write (safeHandle, buf, 0, buf_length, out error);
1041                                                 if (error != MonoIOError.ERROR_SUCCESS) {
1042                                                         // don't leak the path information for isolated storage
1043                                                         throw MonoIO.GetException (GetSecureFileName (name), error);
1044                                                 }
1045                                                 wcount -= n;
1046                                                 offset += n;
1047                                         }
1048 //                              } else {
1049 //                                      st.Write (buf, 0, buf_length);
1050 //                              }
1051                         }
1052
1053                         buf_start += buf_offset;
1054                         buf_offset = buf_length = 0;
1055                         buf_dirty = false;
1056                 }
1057
1058                 private void FlushBufferIfDirty ()
1059                 {
1060                         if (buf_dirty)
1061                                 FlushBuffer ();
1062                 }
1063
1064                 private void RefillBuffer ()
1065                 {
1066                         FlushBuffer ();
1067
1068                         buf_length = ReadData (safeHandle, buf, 0, buf_size);
1069                 }
1070
1071                 private int ReadData (SafeHandle safeHandle, byte[] buf, int offset,
1072                                       int count)
1073                 {
1074                         MonoIOError error;
1075                         int amount = 0;
1076
1077                         /* when async == true, if we get here we don't suport AIO or it's disabled
1078                          * and we're using the threadpool */
1079                         amount = MonoIO.Read (safeHandle, buf, offset, count, out error);
1080                         if (error == MonoIOError.ERROR_BROKEN_PIPE) {
1081                                 amount = 0; // might not be needed, but well...
1082                         } else if (error != MonoIOError.ERROR_SUCCESS) {
1083                                 // don't leak the path information for isolated storage
1084                                 throw MonoIO.GetException (GetSecureFileName (name), error);
1085                         }
1086
1087                         /* Check for read error */
1088                         if(amount == -1) {
1089                                 throw new IOException ();
1090                         }
1091
1092                         return(amount);
1093                 }
1094
1095                 void InitBuffer (int size, bool isZeroSize)
1096                 {
1097                         if (isZeroSize) {
1098                                 size = 0;
1099                                 buf = new byte[1];
1100                         } else {
1101                                 if (size <= 0)
1102                                         throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
1103
1104                                 size = Math.Max (size, 8);
1105
1106                                 //
1107                                 // Instead of allocating a new default buffer use the
1108                                 // last one if there is any available
1109                                 //
1110                                 if (size <= DefaultBufferSize && buf_recycle != null) {
1111                                         lock (buf_recycle_lock) {
1112                                                 if (buf_recycle != null) {
1113                                                         buf = buf_recycle;
1114                                                         buf_recycle = null;
1115                                                 }
1116                                         }
1117                                 }
1118
1119                                 if (buf == null)
1120                                         buf = new byte [size];
1121                                 else
1122                                         Array.Clear (buf, 0, size);
1123                         }
1124
1125                         buf_size = size;
1126 //                      buf_start = 0;
1127 //                      buf_offset = buf_length = 0;
1128 //                      buf_dirty = false;
1129                 }
1130
1131                 private string GetSecureFileName (string filename)
1132                 {
1133                         return (anonymous) ? Path.GetFileName (filename) : Path.GetFullPath (filename);
1134                 }
1135
1136                 private string GetSecureFileName (string filename, bool full)
1137                 {
1138                         return (anonymous) ? Path.GetFileName (filename) :
1139                                 (full) ? Path.GetFullPath (filename) : filename;
1140                 }
1141
1142                 // fields
1143
1144                 internal const int DefaultBufferSize = 4096;
1145
1146                 // Input buffer ready for recycling
1147                 static byte[] buf_recycle;
1148                 static readonly object buf_recycle_lock = new object ();
1149
1150                 private byte [] buf;                    // the buffer
1151                 private string name = "[Unknown]";      // name of file.
1152
1153                 private SafeFileHandle safeHandle;
1154                 private bool isExposed;
1155
1156                 private long append_startpos;
1157
1158                 private FileAccess access;
1159                 private bool owner;
1160                 private bool async;
1161                 private bool canseek;
1162                 private bool anonymous;
1163                 private bool buf_dirty;                 // true if buffer has been written to
1164
1165                 private int buf_size;                   // capacity in bytes
1166                 private int buf_length;                 // number of valid bytes in buffer
1167                 private int buf_offset;                 // position of next byte
1168                 private long buf_start;                 // location of buffer in file
1169         }
1170 }