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 Novell, Inc (http://www.novell.com)
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System.Collections;
  34 using System.Globalization;
  35 using System.Runtime.CompilerServices;
  36 using System.Runtime.InteropServices;
  37 using System.Runtime.Remoting.Messaging;
  38 using System.Security.Permissions;
  39 using System.Threading;
  40
  41 using Microsoft.Win32.SafeHandles;
  42 #if NET_2_1
  43 using System.IO.IsolatedStorage;
  44 using System.Security;
  45 #else
  46 using System.Security.AccessControl;
  47 #endif
  48
  49 namespace System.IO
  50 {
  51         [ComVisible (true)]
  52         public class FileStream : Stream
  53         {
  54                 // construct from handle
  55
  56                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access) instead")]
  57                 public FileStream (IntPtr handle, FileAccess access)
  58                         : this (handle, access, true, DefaultBufferSize, false) {}
  59
  60                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access) instead")]
  61                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle)
  62                         : this (handle, access, ownsHandle, DefaultBufferSize, false) {}
  63
  64                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access, int bufferSize) instead")]
  65                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize)
  66                         : this (handle, access, ownsHandle, bufferSize, false) {}
  67
  68                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access, int bufferSize, bool isAsync) instead")]
  69                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync)
  70                         : this (handle, access, ownsHandle, bufferSize, isAsync, false) {}
  71
  72                 [SecurityPermission (SecurityAction.Demand, UnmanagedCode = true)]
  73                 internal FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync, bool isZeroSize)
  74                 {
  75                         this.handle = MonoIO.InvalidHandle;
  76                         if (handle == this.handle)
  77                                 throw new ArgumentException ("handle", Locale.GetText ("Invalid."));
  78
  79                         if (access < FileAccess.Read || access > FileAccess.ReadWrite)
  80                                 throw new ArgumentOutOfRangeException ("access");
  81
  82                         MonoIOError error;
  83                         MonoFileType ftype = MonoIO.GetFileType (handle, out error);
  84
  85                         if (error != MonoIOError.ERROR_SUCCESS) {
  86                                 throw MonoIO.GetException (name, error);
  87                         }
  88
  89                         if (ftype == MonoFileType.Unknown) {
  90                                 throw new IOException ("Invalid handle.");
  91                         } else if (ftype == MonoFileType.Disk) {
  92                                 this.canseek = true;
  93                         } else {
  94                                 this.canseek = false;
  95                         }
  96
  97                         this.handle = handle;
  98                         this.access = access;
  99                         this.owner = ownsHandle;
 100                         this.async = isAsync;
 101 #if MOONLIGHT
 102                         // default the browser to 'all' anonymous files and let other usage (like smcs) with 'normal'
 103                         // (i.e. non-anonymous except for isolated storage) files and paths
 104                         this.anonymous = SecurityManager.SecurityEnabled;
 105 #else
 106                         this.anonymous = false;
 107 #endif
 108                         if (isZeroSize)
 109                                 bufferSize = 1;
 110
 111                         InitBuffer (bufferSize);
 112
 113                         if (canseek) {
 114                                 buf_start = MonoIO.Seek (handle, 0, SeekOrigin.Current, out error);
 115                                 if (error != MonoIOError.ERROR_SUCCESS) {
 116                                         throw MonoIO.GetException (name, error);
 117                                 }
 118                         }
 119
 120                         /* Can't set append mode */
 121                         this.append_startpos=0;
 122                 }
 123
 124                 // construct from filename
 125
 126                 public FileStream (string path, FileMode mode)
 127                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), FileShare.Read, DefaultBufferSize, false, FileOptions.None)
 128                 {
 129                 }
 130
 131                 public FileStream (string path, FileMode mode, FileAccess access)
 132                         : this (path, mode, access, access == FileAccess.Write ? FileShare.None : FileShare.Read, DefaultBufferSize, false, false)
 133                 {
 134                 }
 135
 136                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share)
 137                         : this (path, mode, access, share, DefaultBufferSize, false, FileOptions.None)
 138                 {
 139                 }
 140
 141                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize)
 142                         : this (path, mode, access, share, bufferSize, false, FileOptions.None)
 143                 {
 144                 }
 145
 146                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool useAsync)
 147                         : this (path, mode, access, share, bufferSize, useAsync, FileOptions.None)
 148                 {
 149                 }
 150
 151 #if !NET_2_1
 152                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options)
 153                         : this (path, mode, access, share, bufferSize, false, options)
 154                 {
 155                 }
 156
 157                 public FileStream (SafeFileHandle handle, FileAccess access)
 158                         :this(handle, access, DefaultBufferSize, false)
 159                 {
 160                 }
 161
 162                 public FileStream (SafeFileHandle handle, FileAccess access,
 163                                    int bufferSize)
 164                         :this(handle, access, bufferSize, false)
 165                 {
 166                 }
 167
 168                 [MonoLimitationAttribute("Need to use SafeFileHandle instead of underlying handle")]
 169                 public FileStream (SafeFileHandle handle, FileAccess access,
 170                                    int bufferSize, bool isAsync)
 171                         :this (handle.DangerousGetHandle (), access, false, bufferSize, isAsync)
 172                 {
 173                         this.safeHandle = handle;
 174                 }
 175
 176                 [MonoLimitation ("This ignores the rights parameter")]
 177                 public FileStream (string path, FileMode mode,
 178                                    FileSystemRights rights, FileShare share,
 179                                    int bufferSize, FileOptions options)
 180                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), share, bufferSize, false, options)
 181                 {
 182                 }
 183
 184                 [MonoLimitation ("This ignores the rights and fileSecurity parameters")]
 185                 public FileStream (string path, FileMode mode,
 186                                    FileSystemRights rights, FileShare share,
 187                                    int bufferSize, FileOptions options,
 188                                    FileSecurity fileSecurity)
 189                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), share, bufferSize, false, options)
 190                 {
 191                 }
 192 #endif
 193
 194                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool isAsync, bool anonymous)
 195                         : this (path, mode, access, share, bufferSize, anonymous, isAsync ? FileOptions.Asynchronous : FileOptions.None)
 196                 {
 197                 }
 198
 199                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool anonymous, FileOptions options)
 200                 {
 201                         if (path == null) {
 202                                 throw new ArgumentNullException ("path");
 203                         }
 204
 205                         if (path.Length == 0) {
 206                                 throw new ArgumentException ("Path is empty");
 207                         }
 208
 209                         // ignore the Inheritable flag
 210                         share &= ~FileShare.Inheritable;
 211
 212                         if (bufferSize <= 0)
 213                                 throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
 214
 215                         if (mode < FileMode.CreateNew || mode > FileMode.Append) {
 216 #if NET_2_1
 217                                 if (anonymous)
 218                                         throw new ArgumentException ("mode", "Enum value was out of legal range.");
 219                                 else
 220 #endif
 221                                 throw new ArgumentOutOfRangeException ("mode", "Enum value was out of legal range.");
 222                         }
 223
 224                         if (access < FileAccess.Read || access > FileAccess.ReadWrite) {
 225 #if NET_2_1
 226                                 if (anonymous)
 227                                         throw new IsolatedStorageException ("Enum value for FileAccess was out of legal range.");
 228                                 else
 229 #endif
 230                                 throw new ArgumentOutOfRangeException ("access", "Enum value was out of legal range.");
 231                         }
 232
 233                         if (share < FileShare.None || share > (FileShare.ReadWrite | FileShare.Delete)) {
 234 #if NET_2_1
 235                                 if (anonymous)
 236                                         throw new IsolatedStorageException ("Enum value for FileShare was out of legal range.");
 237                                 else
 238 #endif
 239                                 throw new ArgumentOutOfRangeException ("share", "Enum value was out of legal range.");
 240                         }
 241
 242                         if (path.IndexOfAny (Path.InvalidPathChars) != -1) {
 243                                 throw new ArgumentException ("Name has invalid chars");
 244                         }
 245
 246                         if (Directory.Exists (path)) {
 247                                 // don't leak the path information for isolated storage
 248                                 string msg = Locale.GetText ("Access to the path '{0}' is denied.");
 249                                 throw new UnauthorizedAccessException (String.Format (msg, GetSecureFileName (path, false)));
 250                         }
 251
 252                         /* Append streams can't be read (see FileMode
 253                          * docs)
 254                          */
 255                         if (mode==FileMode.Append &&
 256                                 (access&FileAccess.Read)==FileAccess.Read) {
 257                                 throw new ArgumentException("Append access can be requested only in write-only mode.");
 258                         }
 259
 260                         if ((access & FileAccess.Write) == 0 &&
 261                                 (mode != FileMode.Open && mode != FileMode.OpenOrCreate)) {
 262                                 string msg = Locale.GetText ("Combining FileMode: {0} with " +
 263                                         "FileAccess: {1} is invalid.");
 264                                 throw new ArgumentException (string.Format (msg, access, mode));
 265                         }
 266
 267                         string dname = Path.GetDirectoryName (path);
 268                         if (dname.Length > 0) {
 269                                 string fp = Path.GetFullPath (dname);
 270                                 if (!Directory.Exists (fp)) {
 271                                         // don't leak the path information for isolated storage
 272                                         string msg = Locale.GetText ("Could not find a part of the path \"{0}\".");
 273                                         string fname = (anonymous) ? dname : Path.GetFullPath (path);
 274 #if NET_2_1
 275                                         // don't use GetSecureFileName for the directory name
 276                                         throw new IsolatedStorageException (String.Format (msg, fname));
 277 #else
 278                                         throw new DirectoryNotFoundException (String.Format (msg, fname));
 279 #endif
 280                                 }
 281                         }
 282
 283                         if (access == FileAccess.Read && mode != FileMode.Create && mode != FileMode.OpenOrCreate &&
 284                                         mode != FileMode.CreateNew && !File.Exists (path)) {
 285                                 // don't leak the path information for isolated storage
 286                                 string msg = Locale.GetText ("Could not find file \"{0}\".");
 287                                 string fname = GetSecureFileName (path);
 288 #if NET_2_1
 289                                 throw new IsolatedStorageException (String.Format (msg, fname));
 290 #else
 291                                 throw new FileNotFoundException (String.Format (msg, fname), fname);
 292 #endif
 293                         }
 294
 295                         // IsolatedStorage needs to keep the Name property to the default "[Unknown]"
 296                         if (!anonymous)
 297                                 this.name = path;
 298
 299                         // TODO: demand permissions
 300
 301                         MonoIOError error;
 302
 303                         this.handle = MonoIO.Open (path, mode, access, share, options, out error);
 304                         if (handle == MonoIO.InvalidHandle) {
 305                                 // don't leak the path information for isolated storage
 306                                 throw MonoIO.GetException (GetSecureFileName (path), error);
 307                         }
 308
 309                         this.access = access;
 310                         this.owner = true;
 311                         this.anonymous = anonymous;
 312
 313                         /* Can we open non-files by name? */
 314
 315                         if (MonoIO.GetFileType (handle, out error) == MonoFileType.Disk) {
 316                                 this.canseek = true;
 317                                 this.async = (options & FileOptions.Asynchronous) != 0;
 318                         } else {
 319                                 this.canseek = false;
 320                                 this.async = false;
 321                         }
 322
 323
 324                         if (access == FileAccess.Read && canseek && (bufferSize == DefaultBufferSize)) {
 325                                 /* Avoid allocating a large buffer for small files */
 326                                 long len = Length;
 327                                 if (bufferSize > len) {
 328                                         bufferSize = (int)(len < 1000 ? 1000 : len);
 329                                 }
 330                         }
 331
 332                         InitBuffer (bufferSize);
 333
 334                         if (mode==FileMode.Append) {
 335                                 this.Seek (0, SeekOrigin.End);
 336                                 this.append_startpos=this.Position;
 337                         } else {
 338                                 this.append_startpos=0;
 339                         }
 340                 }
 341
 342                 // properties
 343
 344                 public override bool CanRead {
 345                         get {
 346                                 return access == FileAccess.Read ||
 347                                        access == FileAccess.ReadWrite;
 348                         }
 349                 }
 350
 351                 public override bool CanWrite {
 352                         get {
 353                                 return access == FileAccess.Write ||
 354                                         access == FileAccess.ReadWrite;
 355                         }
 356                 }
 357
 358                 public override bool CanSeek {
 359                         get {
 360                                 return(canseek);
 361                         }
 362                 }
 363
 364                 public virtual bool IsAsync {
 365                         get {
 366                                 return (async);
 367                         }
 368                 }
 369
 370                 public string Name {
 371                         get {
 372                                 return name;
 373                         }
 374                 }
 375
 376                 public override long Length {
 377                         get {
 378                                 if (handle == MonoIO.InvalidHandle)
 379                                         throw new ObjectDisposedException ("Stream has been closed");
 380
 381                                 if (!CanSeek)
 382                                         throw new NotSupportedException ("The stream does not support seeking");
 383
 384                                 // Buffered data might change the length of the stream
 385                                 FlushBufferIfDirty ();
 386
 387                                 MonoIOError error;
 388                                 long length;
 389
 390                                 length = MonoIO.GetLength (handle, out error);
 391                                 if (error != MonoIOError.ERROR_SUCCESS) {
 392                                         // don't leak the path information for isolated storage
 393                                         throw MonoIO.GetException (GetSecureFileName (name), error);
 394                                 }
 395
 396                                 return(length);
 397                         }
 398                 }
 399
 400                 public override long Position {
 401                         get {
 402                                 if (handle == MonoIO.InvalidHandle)
 403                                         throw new ObjectDisposedException ("Stream has been closed");
 404
 405                                 if(CanSeek == false)
 406                                         throw new NotSupportedException("The stream does not support seeking");
 407
 408                                 return(buf_start + buf_offset);
 409                         }
 410                         set {
 411                                 if (handle == MonoIO.InvalidHandle)
 412                                         throw new ObjectDisposedException ("Stream has been closed");
 413
 414                                 if(CanSeek == false) {
 415                                         throw new NotSupportedException("The stream does not support seeking");
 416                                 }
 417
 418                                 if(value < 0) {
 419                                         throw new ArgumentOutOfRangeException("Attempt to set the position to a negative value");
 420                                 }
 421
 422                                 Seek (value, SeekOrigin.Begin);
 423                         }
 424                 }
 425
 426                 [Obsolete ("Use SafeFileHandle instead")]
 427                 public virtual IntPtr Handle {
 428                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 429                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 430                         get {
 431                                 return handle;
 432                         }
 433                 }
 434
 435                 public virtual SafeFileHandle SafeFileHandle {
 436                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 437                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 438                         get {
 439                                 SafeFileHandle ret;
 440
 441                                 if (safeHandle != null)
 442                                         ret = safeHandle;
 443                                 else
 444                                         ret = new SafeFileHandle (handle, owner);
 445
 446                                 FlushBuffer ();
 447                                 return ret;
 448                         }
 449                 }
 450
 451                 // methods
 452
 453                 public override int ReadByte ()
 454                 {
 455                         if (handle == MonoIO.InvalidHandle)
 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 (handle, 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 (handle == MonoIO.InvalidHandle)
 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 (handle == MonoIO.InvalidHandle)
 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 copied = 0;
 532
 533                         int n = ReadSegment (dest, offset, count);
 534                         copied += n;
 535                         count -= n;
 536
 537                         if (count == 0) {
 538                                 /* If there was already enough
 539                                  * buffered, no need to read
 540                                  * more from the file.
 541                                  */
 542                                 return (copied);
 543                         }
 544
 545                         if (count > buf_size) {
 546                                 /* Read as much as we can, up
 547                                  * to count bytes
 548                                  */
 549                                 FlushBuffer();
 550                                 n = ReadData (handle, dest,
 551                                               offset+copied,
 552                                               count);
 553
 554                                 /* Make the next buffer read
 555                                  * start from the right place
 556                                  */
 557                                 buf_start += n;
 558                         } else {
 559                                 RefillBuffer ();
 560                                 n = ReadSegment (dest,
 561                                                  offset+copied,
 562                                                  count);
 563                         }
 564
 565                         copied += n;
 566
 567                         return copied;
 568                 }
 569
 570                 delegate int ReadDelegate (byte [] buffer, int offset, int count);
 571
 572                 public override IAsyncResult BeginRead (byte [] array, int offset, int numBytes,
 573                                                         AsyncCallback userCallback, object stateObject)
 574                 {
 575                         if (handle == MonoIO.InvalidHandle)
 576                                 throw new ObjectDisposedException ("Stream has been closed");
 577
 578                         if (!CanRead)
 579                                 throw new NotSupportedException ("This stream does not support reading");
 580
 581                         if (array == null)
 582                                 throw new ArgumentNullException ("array");
 583
 584                         if (numBytes < 0)
 585                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 586
 587                         if (offset < 0)
 588                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 589
 590                         // reordered to avoid possible integer overflow
 591                         if (numBytes > array.Length - offset)
 592                                 throw new ArgumentException ("Buffer too small. numBytes/offset wrong.");
 593
 594                         if (!async)
 595                                 return base.BeginRead (array, offset, numBytes, userCallback, stateObject);
 596
 597                         ReadDelegate r = new ReadDelegate (ReadInternal);
 598                         return r.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 599                 }
 600
 601                 public override int EndRead (IAsyncResult asyncResult)
 602                 {
 603                         if (asyncResult == null)
 604                                 throw new ArgumentNullException ("asyncResult");
 605
 606                         if (!async)
 607                                 return base.EndRead (asyncResult);
 608
 609                         AsyncResult ares = asyncResult as AsyncResult;
 610                         if (ares == null)
 611                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 612
 613                         ReadDelegate r = ares.AsyncDelegate as ReadDelegate;
 614                         if (r == null)
 615                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 616
 617                         return r.EndInvoke (asyncResult);
 618                 }
 619
 620                 public override void Write (byte[] array, int offset, int count)
 621                 {
 622                         if (handle == MonoIO.InvalidHandle)
 623                                 throw new ObjectDisposedException ("Stream has been closed");
 624                         if (array == null)
 625                                 throw new ArgumentNullException ("array");
 626                         if (offset < 0)
 627                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 628                         if (count < 0)
 629                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 630                         // ordered to avoid possible integer overflow
 631                         if (offset > array.Length - count)
 632                                 throw new ArgumentException ("Reading would overrun buffer");
 633                         if (!CanWrite)
 634                                 throw new NotSupportedException ("Stream does not support writing");
 635
 636                         if (async) {
 637                                 IAsyncResult ares = BeginWrite (array, offset, count, null, null);
 638                                 EndWrite (ares);
 639                                 return;
 640                         }
 641
 642                         WriteInternal (array, offset, count);
 643                 }
 644
 645                 void WriteInternal (byte [] src, int offset, int count)
 646                 {
 647                         if (count > buf_size) {
 648                                 // shortcut for long writes
 649                                 MonoIOError error;
 650
 651                                 FlushBuffer ();
 652                                 int wcount = count;
 653
 654                                 while (wcount > 0){
 655                                         int n = MonoIO.Write (handle, src, offset, wcount, out error);
 656                                         if (error != MonoIOError.ERROR_SUCCESS)
 657                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 658
 659                                         wcount -= n;
 660                                         offset += n;
 661                                 }
 662                                 buf_start += count;
 663                         } else {
 664
 665                                 int copied = 0;
 666                                 while (count > 0) {
 667
 668                                         int n = WriteSegment (src, offset + copied, count);
 669                                         copied += n;
 670                                         count -= n;
 671
 672                                         if (count == 0) {
 673                                                 break;
 674                                         }
 675
 676                                         FlushBuffer ();
 677                                 }
 678                         }
 679                 }
 680
 681                 delegate void WriteDelegate (byte [] buffer, int offset, int count);
 682
 683                 public override IAsyncResult BeginWrite (byte [] array, int offset, int numBytes,
 684                                                         AsyncCallback userCallback, object stateObject)
 685                 {
 686                         if (handle == MonoIO.InvalidHandle)
 687                                 throw new ObjectDisposedException ("Stream has been closed");
 688
 689                         if (!CanWrite)
 690                                 throw new NotSupportedException ("This stream does not support writing");
 691
 692                         if (array == null)
 693                                 throw new ArgumentNullException ("array");
 694
 695                         if (numBytes < 0)
 696                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 697
 698                         if (offset < 0)
 699                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 700
 701                         // reordered to avoid possible integer overflow
 702                         if (numBytes > array.Length - offset)
 703                                 throw new ArgumentException ("array too small. numBytes/offset wrong.");
 704
 705                         if (!async)
 706                                 return base.BeginWrite (array, offset, numBytes, userCallback, stateObject);
 707
 708                         FileStreamAsyncResult result = new FileStreamAsyncResult (userCallback, stateObject);
 709                         result.BytesRead = -1;
 710                         result.Count = numBytes;
 711                         result.OriginalCount = numBytes;
 712
 713                         if (buf_dirty) {
 714                                 MemoryStream ms = new MemoryStream ();
 715                                 FlushBuffer (ms);
 716                                 ms.Write (array, offset, numBytes);
 717                                 offset = 0;
 718                                 numBytes = (int) ms.Length;
 719                         }
 720
 721                         WriteDelegate w = new WriteDelegate (WriteInternal);
 722                         return w.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 723                 }
 724
 725                 public override void EndWrite (IAsyncResult asyncResult)
 726                 {
 727                         if (asyncResult == null)
 728                                 throw new ArgumentNullException ("asyncResult");
 729
 730                         if (!async) {
 731                                 base.EndWrite (asyncResult);
 732                                 return;
 733                         }
 734
 735                         AsyncResult ares = asyncResult as AsyncResult;
 736                         if (ares == null)
 737                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 738
 739                         WriteDelegate w = ares.AsyncDelegate as WriteDelegate;
 740                         if (w == null)
 741                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 742
 743                         w.EndInvoke (asyncResult);
 744                         return;
 745                 }
 746
 747                 public override long Seek (long offset, SeekOrigin origin)
 748                 {
 749                         long pos;
 750
 751                         if (handle == MonoIO.InvalidHandle)
 752                                 throw new ObjectDisposedException ("Stream has been closed");
 753
 754                         // make absolute
 755
 756                         if(CanSeek == false) {
 757                                 throw new NotSupportedException("The stream does not support seeking");
 758                         }
 759
 760                         switch (origin) {
 761                         case SeekOrigin.End:
 762                                 pos = Length + offset;
 763                                 break;
 764
 765                         case SeekOrigin.Current:
 766                                 pos = Position + offset;
 767                                 break;
 768
 769                         case SeekOrigin.Begin:
 770                                 pos = offset;
 771                                 break;
 772
 773                         default:
 774                                 throw new ArgumentException ("origin", "Invalid SeekOrigin");
 775                         }
 776
 777                         if (pos < 0) {
 778                                 /* LAMESPEC: shouldn't this be
 779                                  * ArgumentOutOfRangeException?
 780                                  */
 781                                 throw new IOException("Attempted to Seek before the beginning of the stream");
 782                         }
 783
 784                         if(pos < this.append_startpos) {
 785                                 /* More undocumented crap */
 786                                 throw new IOException("Can't seek back over pre-existing data in append mode");
 787                         }
 788
 789                         FlushBuffer ();
 790
 791                         MonoIOError error;
 792
 793                         buf_start = MonoIO.Seek (handle, pos,
 794                                                  SeekOrigin.Begin,
 795                                                  out error);
 796
 797                         if (error != MonoIOError.ERROR_SUCCESS) {
 798                                 // don't leak the path information for isolated storage
 799                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 800                         }
 801
 802                         return(buf_start);
 803                 }
 804
 805                 public override void SetLength (long value)
 806                 {
 807                         if (handle == MonoIO.InvalidHandle)
 808                                 throw new ObjectDisposedException ("Stream has been closed");
 809
 810                         if(CanSeek == false)
 811                                 throw new NotSupportedException("The stream does not support seeking");
 812
 813                         if(CanWrite == false)
 814                                 throw new NotSupportedException("The stream does not support writing");
 815
 816                         if(value < 0)
 817                                 throw new ArgumentOutOfRangeException("value is less than 0");
 818
 819                         Flush ();
 820
 821                         MonoIOError error;
 822
 823                         MonoIO.SetLength (handle, value, out error);
 824                         if (error != MonoIOError.ERROR_SUCCESS) {
 825                                 // don't leak the path information for isolated storage
 826                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 827                         }
 828
 829                         if (Position > value)
 830                                 Position = value;
 831                 }
 832
 833                 public override void Flush ()
 834                 {
 835                         if (handle == MonoIO.InvalidHandle)
 836                                 throw new ObjectDisposedException ("Stream has been closed");
 837
 838                         FlushBuffer ();
 839                 }
 840
 841 #if NET_4_0
 842                 public virtual void Flush (bool flushToDisk)
 843                 {
 844                         FlushBuffer ();
 845
 846                         // This does the fsync
 847                         if (flushToDisk){
 848                                 MonoIOError error;
 849                                 MonoIO.Flush (handle, out error);
 850                         }
 851                 }
 852 #endif
 853
 854                 public virtual void Lock (long position, long length)
 855                 {
 856                         if (handle == MonoIO.InvalidHandle)
 857                                 throw new ObjectDisposedException ("Stream has been closed");
 858                         if (position < 0) {
 859                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 860                         }
 861                         if (length < 0) {
 862                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 863                         }
 864                         if (handle == MonoIO.InvalidHandle) {
 865                                 throw new ObjectDisposedException ("Stream has been closed");
 866                         }
 867
 868                         MonoIOError error;
 869
 870                         MonoIO.Lock (handle, position, length, out error);
 871                         if (error != MonoIOError.ERROR_SUCCESS) {
 872                                 // don't leak the path information for isolated storage
 873                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 874                         }
 875                 }
 876
 877                 public virtual void Unlock (long position, long length)
 878                 {
 879                         if (handle == MonoIO.InvalidHandle)
 880                                 throw new ObjectDisposedException ("Stream has been closed");
 881                         if (position < 0) {
 882                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 883                         }
 884                         if (length < 0) {
 885                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 886                         }
 887
 888                         MonoIOError error;
 889
 890                         MonoIO.Unlock (handle, position, length, out error);
 891                         if (error != MonoIOError.ERROR_SUCCESS) {
 892                                 // don't leak the path information for isolated storage
 893                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 894                         }
 895                 }
 896
 897                 // protected
 898
 899                 ~FileStream ()
 900                 {
 901                         Dispose (false);
 902                 }
 903
 904                 protected override void Dispose (bool disposing)
 905                 {
 906                         Exception exc = null;
 907                         if (handle != MonoIO.InvalidHandle) {
 908                                 try {
 909                                         FlushBuffer ();
 910                                 } catch (Exception e) {
 911                                         exc = e;
 912                                 }
 913
 914                                 if (owner) {
 915                                         MonoIOError error;
 916
 917                                         MonoIO.Close (handle, out error);
 918                                         if (error != MonoIOError.ERROR_SUCCESS) {
 919                                                 // don't leak the path information for isolated storage
 920                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 921                                         }
 922
 923                                         handle = MonoIO.InvalidHandle;
 924                                 }
 925                         }
 926
 927                         canseek = false;
 928                         access = 0;
 929
 930                         if (disposing && buf != null) {
 931                                 if (buf.Length == DefaultBufferSize && buf_recycle == null) {
 932                                         lock (buf_recycle_lock) {
 933                                                 if (buf_recycle == null) {
 934                                                         buf_recycle = buf;
 935                                                 }
 936                                         }
 937                                 }
 938
 939                                 buf = null;
 940                                 GC.SuppressFinalize (this);
 941                         }
 942                         if (exc != null)
 943                                 throw exc;
 944                 }
 945
 946 #if !NET_2_1
 947                 public FileSecurity GetAccessControl ()
 948                 {
 949                         throw new NotImplementedException ();
 950                 }
 951
 952                 public void SetAccessControl (FileSecurity fileSecurity)
 953                 {
 954                         throw new NotImplementedException ();
 955                 }
 956 #endif
 957
 958                 // private.
 959
 960                 // ReadSegment, WriteSegment, FlushBuffer,
 961                 // RefillBuffer and ReadData should only be called
 962                 // when the Monitor lock is held, but these methods
 963                 // grab it again just to be safe.
 964
 965                 private int ReadSegment (byte [] dest, int dest_offset, int count)
 966                 {
 967                         if (count > buf_length - buf_offset) {
 968                                 count = buf_length - buf_offset;
 969                         }
 970
 971                         if (count > 0) {
 972                                 Buffer.BlockCopy (buf, buf_offset,
 973                                                   dest, dest_offset,
 974                                                   count);
 975                                 buf_offset += count;
 976                         }
 977
 978                         return(count);
 979                 }
 980
 981                 private int WriteSegment (byte [] src, int src_offset,
 982                                           int count)
 983                 {
 984                         if (count > buf_size - buf_offset) {
 985                                 count = buf_size - buf_offset;
 986                         }
 987
 988                         if (count > 0) {
 989                                 Buffer.BlockCopy (src, src_offset,
 990                                                   buf, buf_offset,
 991                                                   count);
 992                                 buf_offset += count;
 993                                 if (buf_offset > buf_length) {
 994                                         buf_length = buf_offset;
 995                                 }
 996
 997                                 buf_dirty = true;
 998                         }
 999
1000                         return(count);
1001                 }
1002
1003                 void FlushBuffer (Stream st)
1004                 {
1005                         if (buf_dirty) {
1006                                 MonoIOError error;
1007
1008                                 if (CanSeek == true) {
1009                                         MonoIO.Seek (handle, buf_start,
1010                                                      SeekOrigin.Begin,
1011                                                      out error);
1012                                         if (error != MonoIOError.ERROR_SUCCESS) {
1013                                                 // don't leak the path information for isolated storage
1014                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
1015                                         }
1016                                 }
1017                                 if (st == null) {
1018                                         int wcount = buf_length;
1019                                         int offset = 0;
1020                                         while (wcount > 0){
1021                                                 int n = MonoIO.Write (handle, buf, 0, buf_length, out error);
1022                                                 if (error != MonoIOError.ERROR_SUCCESS) {
1023                                                         // don't leak the path information for isolated storage
1024                                                         throw MonoIO.GetException (GetSecureFileName (name), error);
1025                                                 }
1026                                                 wcount -= n;
1027                                                 offset += n;
1028                                         }
1029                                 } else {
1030                                         st.Write (buf, 0, buf_length);
1031                                 }
1032                         }
1033
1034                         buf_start += buf_offset;
1035                         buf_offset = buf_length = 0;
1036                         buf_dirty = false;
1037                 }
1038
1039                 private void FlushBuffer ()
1040                 {
1041                         FlushBuffer (null);
1042                 }
1043
1044                 private void FlushBufferIfDirty ()
1045                 {
1046                         if (buf_dirty)
1047                                 FlushBuffer (null);
1048                 }
1049
1050                 private void RefillBuffer ()
1051                 {
1052                         FlushBuffer (null);
1053
1054                         buf_length = ReadData (handle, buf, 0,
1055                                                buf_size);
1056                 }
1057
1058                 private int ReadData (IntPtr handle, byte[] buf, int offset,
1059                                       int count)
1060                 {
1061                         MonoIOError error;
1062                         int amount = 0;
1063
1064                         /* when async == true, if we get here we don't suport AIO or it's disabled
1065                          * and we're using the threadpool */
1066                         amount = MonoIO.Read (handle, buf, offset, count, out error);
1067                         if (error == MonoIOError.ERROR_BROKEN_PIPE) {
1068                                 amount = 0; // might not be needed, but well...
1069                         } else if (error != MonoIOError.ERROR_SUCCESS) {
1070                                 // don't leak the path information for isolated storage
1071                                 throw MonoIO.GetException (GetSecureFileName (name), error);
1072                         }
1073
1074                         /* Check for read error */
1075                         if(amount == -1) {
1076                                 throw new IOException ();
1077                         }
1078
1079                         return(amount);
1080                 }
1081
1082                 void InitBuffer (int size)
1083                 {
1084                         if (size <= 0)
1085                                 throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
1086
1087                         size = Math.Max (size, 8);
1088
1089                         //
1090                         // Instead of allocating a new default buffer use the
1091                         // last one if there is any available
1092                         //
1093                         if (size <= DefaultBufferSize && buf_recycle != null) {
1094                                 lock (buf_recycle_lock) {
1095                                         if (buf_recycle != null) {
1096                                                 buf = buf_recycle;
1097                                                 buf_recycle = null;
1098                                         }
1099                                 }
1100                         }
1101
1102                         if (buf == null)
1103                                 buf = new byte [size];
1104                         else
1105                                 Array.Clear (buf, 0, size);
1106
1107                         buf_size = size;
1108 //                      buf_start = 0;
1109 //                      buf_offset = buf_length = 0;
1110 //                      buf_dirty = false;
1111                 }
1112
1113                 private string GetSecureFileName (string filename)
1114                 {
1115                         return (anonymous) ? Path.GetFileName (filename) : Path.GetFullPath (filename);
1116                 }
1117
1118                 private string GetSecureFileName (string filename, bool full)
1119                 {
1120                         return (anonymous) ? Path.GetFileName (filename) :
1121                                 (full) ? Path.GetFullPath (filename) : filename;
1122                 }
1123
1124                 // fields
1125
1126                 internal const int DefaultBufferSize = 8192;
1127
1128                 // Input buffer ready for recycling
1129                 static byte[] buf_recycle;
1130                 static readonly object buf_recycle_lock = new object ();
1131
1132                 private FileAccess access;
1133                 private bool owner;
1134                 private bool async;
1135                 private bool canseek;
1136                 private long append_startpos;
1137                 private bool anonymous;
1138
1139                 private byte [] buf;                    // the buffer
1140                 private int buf_size;                   // capacity in bytes
1141                 private int buf_length;                 // number of valid bytes in buffer
1142                 private int buf_offset;                 // position of next byte
1143                 private bool buf_dirty;                 // true if buffer has been written to
1144                 private long buf_start;                 // location of buffer in file
1145                 private string name = "[Unknown]";      // name of file.
1146
1147                 IntPtr handle;                          // handle to underlying file
1148                 SafeFileHandle safeHandle;              // set only when using one of the
1149                                                         // constructors taking SafeFileHandle
1150         }
1151 }