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

   1 //
   2 // System.IO.FileStream.cs
   3 //
   4 // Authors:
   5 //      Dietmar Maurer (dietmar@ximian.com)
   6 //      Dan Lewis (dihlewis@yahoo.co.uk)
   7 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   8 //  Marek Safar (marek.safar@gmail.com)
   9 //
  10 // (C) 2001-2003 Ximian, Inc.  http://www.ximian.com
  11 // Copyright (C) 2004-2005, 2008, 2010 Novell, Inc (http://www.novell.com)
  12 // Copyright 2011 Xamarin Inc (http://www.xamarin.com).
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.Collections;
  35 using System.Globalization;
  36 using System.Runtime.CompilerServices;
  37 using System.Runtime.InteropServices;
  38 using System.Runtime.Remoting.Messaging;
  39 using System.Security;
  40 using System.Security.AccessControl;
  41 using System.Security.Permissions;
  42 using System.Threading;
  43 using System.Threading.Tasks;
  44 using Microsoft.Win32.SafeHandles;
  45
  46 namespace System.IO
  47 {
  48         [ComVisible (true)]
  49         public class FileStream : Stream
  50         {
  51                 // construct from handle
  52
  53                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access) instead")]
  54                 public FileStream (IntPtr handle, FileAccess access)
  55                         : this (handle, access, true, DefaultBufferSize, false, false) {}
  56
  57                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access) instead")]
  58                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle)
  59                         : this (handle, access, ownsHandle, DefaultBufferSize, false, false) {}
  60
  61                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access, int bufferSize) instead")]
  62                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize)
  63                         : this (handle, access, ownsHandle, bufferSize, false, false) {}
  64
  65                 [Obsolete ("Use FileStream(SafeFileHandle handle, FileAccess access, int bufferSize, bool isAsync) instead")]
  66                 public FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync)
  67                         : this (handle, access, ownsHandle, bufferSize, isAsync, false) {}
  68
  69                 [SecurityPermission (SecurityAction.Demand, UnmanagedCode = true)]
  70                 internal FileStream (IntPtr handle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync, bool isConsoleWrapper)
  71                 {
  72                         if (handle == MonoIO.InvalidHandle)
  73                                 throw new ArgumentException ("handle", Locale.GetText ("Invalid."));
  74
  75                         Init (new SafeFileHandle (handle, false), access, ownsHandle, bufferSize, isAsync, isConsoleWrapper);
  76                 }
  77
  78                 // construct from filename
  79
  80                 public FileStream (string path, FileMode mode)
  81                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), FileShare.Read, DefaultBufferSize, false, FileOptions.None)
  82                 {
  83                 }
  84
  85                 public FileStream (string path, FileMode mode, FileAccess access)
  86                         : this (path, mode, access, access == FileAccess.Write ? FileShare.None : FileShare.Read, DefaultBufferSize, false, false)
  87                 {
  88                 }
  89
  90                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share)
  91                         : this (path, mode, access, share, DefaultBufferSize, false, FileOptions.None)
  92                 {
  93                 }
  94
  95                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize)
  96                         : this (path, mode, access, share, bufferSize, false, FileOptions.None)
  97                 {
  98                 }
  99
 100                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool useAsync)
 101                         : this (path, mode, access, share, bufferSize, useAsync ? FileOptions.Asynchronous : FileOptions.None)
 102                 {
 103                 }
 104
 105                 public FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options)
 106                         : this (path, mode, access, share, bufferSize, false, options)
 107                 {
 108                 }
 109
 110                 public FileStream (SafeFileHandle handle, FileAccess access)
 111                         :this(handle, access, DefaultBufferSize, false)
 112                 {
 113                 }
 114
 115                 public FileStream (SafeFileHandle handle, FileAccess access,
 116                                    int bufferSize)
 117                         :this(handle, access, bufferSize, false)
 118                 {
 119                 }
 120
 121                 public FileStream (SafeFileHandle handle, FileAccess access, int bufferSize, bool isAsync)
 122                 {
 123                         Init (handle, access, false, bufferSize, isAsync, false);
 124                 }
 125
 126                 [MonoLimitation ("This ignores the rights parameter")]
 127                 public FileStream (string path, FileMode mode,
 128                                    FileSystemRights rights, FileShare share,
 129                                    int bufferSize, FileOptions options)
 130                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), share, bufferSize, false, options)
 131                 {
 132                 }
 133
 134                 [MonoLimitation ("This ignores the rights and fileSecurity parameters")]
 135                 public FileStream (string path, FileMode mode,
 136                                    FileSystemRights rights, FileShare share,
 137                                    int bufferSize, FileOptions options,
 138                                    FileSecurity fileSecurity)
 139                         : this (path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), share, bufferSize, false, options)
 140                 {
 141                 }
 142
 143                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options, string msgPath, bool bFromProxy, bool useLongPath = false, bool checkHost = false)
 144                         : this (path, mode, access, share, bufferSize, false, options)
 145                 {
 146                 }
 147
 148                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool isAsync, bool anonymous)
 149                         : this (path, mode, access, share, bufferSize, anonymous, isAsync ? FileOptions.Asynchronous : FileOptions.None)
 150                 {
 151                 }
 152
 153                 internal FileStream (string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool anonymous, FileOptions options)
 154                 {
 155                         if (path == null) {
 156                                 throw new ArgumentNullException ("path");
 157                         }
 158
 159                         if (path.Length == 0) {
 160                                 throw new ArgumentException ("Path is empty");
 161                         }
 162
 163                         this.anonymous = anonymous;
 164                         // ignore the Inheritable flag
 165                         share &= ~FileShare.Inheritable;
 166
 167                         if (bufferSize <= 0)
 168                                 throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
 169
 170                         if (mode < FileMode.CreateNew || mode > FileMode.Append) {
 171 #if MOBILE
 172                                 if (anonymous)
 173                                         throw new ArgumentException ("mode", "Enum value was out of legal range.");
 174                                 else
 175 #endif
 176                                 throw new ArgumentOutOfRangeException ("mode", "Enum value was out of legal range.");
 177                         }
 178
 179                         if (access < FileAccess.Read || access > FileAccess.ReadWrite) {
 180                                 throw new ArgumentOutOfRangeException ("access", "Enum value was out of legal range.");
 181                         }
 182
 183                         if (share < FileShare.None || share > (FileShare.ReadWrite | FileShare.Delete)) {
 184                                 throw new ArgumentOutOfRangeException ("share", "Enum value was out of legal range.");
 185                         }
 186
 187                         if (path.IndexOfAny (Path.InvalidPathChars) != -1) {
 188                                 throw new ArgumentException ("Name has invalid chars");
 189                         }
 190
 191                         if (Directory.Exists (path)) {
 192                                 // don't leak the path information for isolated storage
 193                                 string msg = Locale.GetText ("Access to the path '{0}' is denied.");
 194                                 throw new UnauthorizedAccessException (String.Format (msg, GetSecureFileName (path, false)));
 195                         }
 196
 197                         /* Append streams can't be read (see FileMode
 198                          * docs)
 199                          */
 200                         if (mode==FileMode.Append &&
 201                                 (access&FileAccess.Read)==FileAccess.Read) {
 202                                 throw new ArgumentException("Append access can be requested only in write-only mode.");
 203                         }
 204
 205                         if ((access & FileAccess.Write) == 0 &&
 206                                 (mode != FileMode.Open && mode != FileMode.OpenOrCreate)) {
 207                                 string msg = Locale.GetText ("Combining FileMode: {0} with " +
 208                                         "FileAccess: {1} is invalid.");
 209                                 throw new ArgumentException (string.Format (msg, access, mode));
 210                         }
 211
 212                         SecurityManager.EnsureElevatedPermissions (); // this is a no-op outside moonlight
 213
 214                         string dname;
 215                         if (Path.DirectorySeparatorChar != '/' && path.IndexOf ('/') >= 0)
 216                                 dname = Path.GetDirectoryName (Path.GetFullPath (path));
 217                         else
 218                                 dname = Path.GetDirectoryName (path);
 219                         if (dname.Length > 0) {
 220                                 string fp = Path.GetFullPath (dname);
 221                                 if (!Directory.Exists (fp)) {
 222                                         // don't leak the path information for isolated storage
 223                                         string msg = Locale.GetText ("Could not find a part of the path \"{0}\".");
 224                                         string fname = (anonymous) ? dname : Path.GetFullPath (path);
 225                                         throw new DirectoryNotFoundException (String.Format (msg, fname));
 226                                 }
 227                         }
 228
 229                         if (access == FileAccess.Read && mode != FileMode.Create && mode != FileMode.OpenOrCreate &&
 230                                         mode != FileMode.CreateNew && !File.Exists (path)) {
 231                                 // don't leak the path information for isolated storage
 232                                 string msg = Locale.GetText ("Could not find file \"{0}\".");
 233                                 string fname = GetSecureFileName (path);
 234                                 throw new FileNotFoundException (String.Format (msg, fname), fname);
 235                         }
 236
 237                         // IsolatedStorage needs to keep the Name property to the default "[Unknown]"
 238                         if (!anonymous)
 239                                 this.name = path;
 240
 241                         // TODO: demand permissions
 242
 243                         MonoIOError error;
 244
 245                         var nativeHandle = MonoIO.Open (path, mode, access, share, options, out error);
 246
 247                         if (nativeHandle == MonoIO.InvalidHandle) {
 248                                 // don't leak the path information for isolated storage
 249                                 throw MonoIO.GetException (GetSecureFileName (path), error);
 250                         }
 251
 252                         this.safeHandle = new SafeFileHandle (nativeHandle, false);
 253
 254                         this.access = access;
 255                         this.owner = true;
 256
 257                         /* Can we open non-files by name? */
 258
 259                         if (MonoIO.GetFileType (safeHandle, out error) == MonoFileType.Disk) {
 260                                 this.canseek = true;
 261                                 this.async = (options & FileOptions.Asynchronous) != 0;
 262                         } else {
 263                                 this.canseek = false;
 264                                 this.async = false;
 265                         }
 266
 267
 268                         if (access == FileAccess.Read && canseek && (bufferSize == DefaultBufferSize)) {
 269                                 /* Avoid allocating a large buffer for small files */
 270                                 long len = Length;
 271                                 if (bufferSize > len) {
 272                                         bufferSize = (int)(len < 1000 ? 1000 : len);
 273                                 }
 274                         }
 275
 276                         InitBuffer (bufferSize, false);
 277
 278                         if (mode==FileMode.Append) {
 279                                 this.Seek (0, SeekOrigin.End);
 280                                 this.append_startpos=this.Position;
 281                         } else {
 282                                 this.append_startpos=0;
 283                         }
 284                 }
 285
 286                 private void Init (SafeFileHandle safeHandle, FileAccess access, bool ownsHandle, int bufferSize, bool isAsync, bool isConsoleWrapper)
 287                 {
 288                         if (!isConsoleWrapper && safeHandle.IsInvalid)
 289                                 throw new ArgumentException(Environment.GetResourceString("Arg_InvalidHandle"), "handle");
 290                         if (access < FileAccess.Read || access > FileAccess.ReadWrite)
 291                                 throw new ArgumentOutOfRangeException ("access");
 292                         if (!isConsoleWrapper && bufferSize <= 0)
 293                                 throw new ArgumentOutOfRangeException("bufferSize", Environment.GetResourceString("ArgumentOutOfRange_NeedPosNum"));
 294
 295                         MonoIOError error;
 296                         MonoFileType ftype = MonoIO.GetFileType (safeHandle, out error);
 297
 298                         if (error != MonoIOError.ERROR_SUCCESS) {
 299                                 throw MonoIO.GetException (name, error);
 300                         }
 301
 302                         if (ftype == MonoFileType.Unknown) {
 303                                 throw new IOException ("Invalid handle.");
 304                         } else if (ftype == MonoFileType.Disk) {
 305                                 this.canseek = true;
 306                         } else {
 307                                 this.canseek = false;
 308                         }
 309
 310                         this.safeHandle = safeHandle;
 311                         ExposeHandle ();
 312                         this.access = access;
 313                         this.owner = ownsHandle;
 314                         this.async = isAsync;
 315                         this.anonymous = false;
 316
 317                         if (canseek) {
 318                                 buf_start = MonoIO.Seek (safeHandle, 0, SeekOrigin.Current, out error);
 319                                 if (error != MonoIOError.ERROR_SUCCESS) {
 320                                         throw MonoIO.GetException (name, error);
 321                                 }
 322                         }
 323
 324                         /* Can't set append mode */
 325                         this.append_startpos=0;
 326                 }
 327
 328                 // properties
 329
 330                 public override bool CanRead {
 331                         get {
 332                                 return access == FileAccess.Read ||
 333                                        access == FileAccess.ReadWrite;
 334                         }
 335                 }
 336
 337                 public override bool CanWrite {
 338                         get {
 339                                 return access == FileAccess.Write ||
 340                                         access == FileAccess.ReadWrite;
 341                         }
 342                 }
 343
 344                 public override bool CanSeek {
 345                         get {
 346                                 return(canseek);
 347                         }
 348                 }
 349
 350                 public virtual bool IsAsync {
 351                         get {
 352                                 return (async);
 353                         }
 354                 }
 355
 356                 public string Name {
 357                         get {
 358                                 return name;
 359                         }
 360                 }
 361
 362                 public override long Length {
 363                         get {
 364                                 if (safeHandle.IsClosed)
 365                                         throw new ObjectDisposedException ("Stream has been closed");
 366
 367                                 if (!CanSeek)
 368                                         throw new NotSupportedException ("The stream does not support seeking");
 369
 370                                 // Buffered data might change the length of the stream
 371                                 FlushBufferIfDirty ();
 372
 373                                 MonoIOError error;
 374
 375                                 long length = MonoIO.GetLength (safeHandle, out error);
 376
 377                                 if (error != MonoIOError.ERROR_SUCCESS) {
 378                                         // don't leak the path information for isolated storage
 379                                         throw MonoIO.GetException (GetSecureFileName (name), error);
 380                                 }
 381
 382                                 return(length);
 383                         }
 384                 }
 385
 386                 public override long Position {
 387                         get {
 388                                 if (safeHandle.IsClosed)
 389                                         throw new ObjectDisposedException ("Stream has been closed");
 390
 391                                 if (CanSeek == false)
 392                                         throw new NotSupportedException("The stream does not support seeking");
 393
 394                                 if (!isExposed)
 395                                         return(buf_start + buf_offset);
 396
 397                                 // If the handle was leaked outside we always ask the real handle
 398                                 MonoIOError error;
 399
 400                                 long ret = MonoIO.Seek (safeHandle, 0, SeekOrigin.Current, out error);
 401
 402                                 if (error != MonoIOError.ERROR_SUCCESS) {
 403                                         // don't leak the path information for isolated storage
 404                                         throw MonoIO.GetException (GetSecureFileName (name), error);
 405                                 }
 406
 407                                 return ret;
 408                         }
 409                         set {
 410                                 if (value < 0) throw new ArgumentOutOfRangeException("value", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
 411
 412                                 Seek (value, SeekOrigin.Begin);
 413                         }
 414                 }
 415
 416                 [Obsolete ("Use SafeFileHandle instead")]
 417                 public virtual IntPtr Handle {
 418                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 419                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 420                         get {
 421                                 var handle = safeHandle.DangerousGetHandle ();
 422                                 if (!isExposed)
 423                                         ExposeHandle ();
 424                                 return handle;
 425                         }
 426                 }
 427
 428                 public virtual SafeFileHandle SafeFileHandle {
 429                         [SecurityPermission (SecurityAction.LinkDemand, UnmanagedCode = true)]
 430                         [SecurityPermission (SecurityAction.InheritanceDemand, UnmanagedCode = true)]
 431                         get {
 432                                 if (!isExposed)
 433                                         ExposeHandle ();
 434                                 return safeHandle;
 435                         }
 436                 }
 437
 438                 void ExposeHandle ()
 439                 {
 440                         isExposed = true;
 441                         FlushBuffer ();
 442                         InitBuffer (0, true);
 443                 }
 444
 445                 // methods
 446
 447                 public override int ReadByte ()
 448                 {
 449                         if (safeHandle.IsClosed)
 450                                 throw new ObjectDisposedException ("Stream has been closed");
 451
 452                         if (!CanRead)
 453                                 throw new NotSupportedException ("Stream does not support reading");
 454
 455                         if (buf_size == 0) {
 456                                 int n = ReadData (safeHandle, buf, 0, 1);
 457                                 if (n == 0) return -1;
 458                                 else return buf[0];
 459                         }
 460                         else if (buf_offset >= buf_length) {
 461                                 RefillBuffer ();
 462
 463                                 if (buf_length == 0)
 464                                         return -1;
 465                         }
 466
 467                         return buf [buf_offset ++];
 468                 }
 469
 470                 public override void WriteByte (byte value)
 471                 {
 472                         if (safeHandle.IsClosed)
 473                                 throw new ObjectDisposedException ("Stream has been closed");
 474
 475                         if (!CanWrite)
 476                                 throw new NotSupportedException ("Stream does not support writing");
 477
 478                         if (buf_offset == buf_size)
 479                                 FlushBuffer ();
 480
 481                         if (buf_size == 0) { // No buffering
 482                                 buf [0] = value;
 483                                 buf_dirty = true;
 484                                 buf_length = 1;
 485                                 FlushBuffer ();
 486                                 return;
 487                         }
 488
 489                         buf [buf_offset ++] = value;
 490                         if (buf_offset > buf_length)
 491                                 buf_length = buf_offset;
 492
 493                         buf_dirty = true;
 494                 }
 495
 496                 public override int Read ([In,Out] byte[] array, int offset, int count)
 497                 {
 498                         if (safeHandle.IsClosed)
 499                                 throw new ObjectDisposedException ("Stream has been closed");
 500                         if (array == null)
 501                                 throw new ArgumentNullException ("array");
 502                         if (!CanRead)
 503                                 throw new NotSupportedException ("Stream does not support reading");
 504                         int len = array.Length;
 505                         if (offset < 0)
 506                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 507                         if (count < 0)
 508                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 509                         if (offset > len)
 510                                 throw new ArgumentException ("destination offset is beyond array size");
 511                         // reordered to avoid possible integer overflow
 512                         if (offset > len - count)
 513                                 throw new ArgumentException ("Reading would overrun buffer");
 514
 515                         if (async) {
 516                                 IAsyncResult ares = BeginRead (array, offset, count, null, null);
 517                                 return EndRead (ares);
 518                         }
 519
 520                         return ReadInternal (array, offset, count);
 521                 }
 522
 523                 int ReadInternal (byte [] dest, int offset, int count)
 524                 {
 525                         int n = ReadSegment (dest, offset, count);
 526                         if (n == count) {
 527                                 return count;
 528                         }
 529
 530                         int copied = n;
 531                         count -= n;
 532
 533                         if (count > buf_size) {
 534                                 /* Read as much as we can, up
 535                                  * to count bytes
 536                                  */
 537                                 FlushBuffer();
 538                                 n = ReadData (safeHandle, dest, offset+n, count);
 539
 540                                 /* Make the next buffer read
 541                                  * start from the right place
 542                                  */
 543                                 buf_start += n;
 544                         } else {
 545                                 RefillBuffer ();
 546                                 n = ReadSegment (dest, offset+copied, count);
 547                         }
 548
 549                         return copied + n;
 550                 }
 551
 552                 delegate int ReadDelegate (byte [] buffer, int offset, int count);
 553
 554                 public override IAsyncResult BeginRead (byte [] array, int offset, int numBytes,
 555                                                         AsyncCallback userCallback, object stateObject)
 556                 {
 557                         if (safeHandle.IsClosed)
 558                                 throw new ObjectDisposedException ("Stream has been closed");
 559
 560                         if (!CanRead)
 561                                 throw new NotSupportedException ("This stream does not support reading");
 562
 563                         if (array == null)
 564                                 throw new ArgumentNullException ("array");
 565
 566                         if (numBytes < 0)
 567                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 568
 569                         if (offset < 0)
 570                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 571
 572                         // reordered to avoid possible integer overflow
 573                         if (numBytes > array.Length - offset)
 574                                 throw new ArgumentException ("Buffer too small. numBytes/offset wrong.");
 575
 576                         if (!async)
 577                                 return base.BeginRead (array, offset, numBytes, userCallback, stateObject);
 578
 579                         ReadDelegate r = new ReadDelegate (ReadInternal);
 580                         return r.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 581                 }
 582
 583                 public override int EndRead (IAsyncResult asyncResult)
 584                 {
 585                         if (asyncResult == null)
 586                                 throw new ArgumentNullException ("asyncResult");
 587
 588                         if (!async)
 589                                 return base.EndRead (asyncResult);
 590
 591                         AsyncResult ares = asyncResult as AsyncResult;
 592                         if (ares == null)
 593                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 594
 595                         ReadDelegate r = ares.AsyncDelegate as ReadDelegate;
 596                         if (r == null)
 597                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 598
 599                         return r.EndInvoke (asyncResult);
 600                 }
 601
 602                 public override void Write (byte[] array, int offset, int count)
 603                 {
 604                         if (safeHandle.IsClosed)
 605                                 throw new ObjectDisposedException ("Stream has been closed");
 606                         if (array == null)
 607                                 throw new ArgumentNullException ("array");
 608                         if (offset < 0)
 609                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 610                         if (count < 0)
 611                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 612                         // ordered to avoid possible integer overflow
 613                         if (offset > array.Length - count)
 614                                 throw new ArgumentException ("Reading would overrun buffer");
 615                         if (!CanWrite)
 616                                 throw new NotSupportedException ("Stream does not support writing");
 617
 618                         if (async) {
 619                                 IAsyncResult ares = BeginWrite (array, offset, count, null, null);
 620                                 EndWrite (ares);
 621                                 return;
 622                         }
 623
 624                         WriteInternal (array, offset, count);
 625                 }
 626
 627                 void WriteInternal (byte [] src, int offset, int count)
 628                 {
 629                         if (count > buf_size) {
 630                                 // shortcut for long writes
 631                                 MonoIOError error;
 632
 633                                 FlushBuffer ();
 634
 635                                 if (CanSeek && !isExposed) {
 636                                         MonoIO.Seek (safeHandle, buf_start, SeekOrigin.Begin, out error);
 637                                         if (error != MonoIOError.ERROR_SUCCESS)
 638                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 639                                 }
 640
 641                                 int wcount = count;
 642
 643                                 while (wcount > 0){
 644                                         int n = MonoIO.Write (safeHandle, src, offset, wcount, out error);
 645                                         if (error != MonoIOError.ERROR_SUCCESS)
 646                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 647
 648                                         wcount -= n;
 649                                         offset += n;
 650                                 }
 651                                 buf_start += count;
 652                         } else {
 653
 654                                 int copied = 0;
 655                                 while (count > 0) {
 656
 657                                         int n = WriteSegment (src, offset + copied, count);
 658                                         copied += n;
 659                                         count -= n;
 660
 661                                         if (count == 0) {
 662                                                 break;
 663                                         }
 664
 665                                         FlushBuffer ();
 666                                 }
 667                         }
 668                 }
 669
 670                 delegate void WriteDelegate (byte [] buffer, int offset, int count);
 671
 672                 public override IAsyncResult BeginWrite (byte [] array, int offset, int numBytes,
 673                                                         AsyncCallback userCallback, object stateObject)
 674                 {
 675                         if (safeHandle.IsClosed)
 676                                 throw new ObjectDisposedException ("Stream has been closed");
 677
 678                         if (!CanWrite)
 679                                 throw new NotSupportedException ("This stream does not support writing");
 680
 681                         if (array == null)
 682                                 throw new ArgumentNullException ("array");
 683
 684                         if (numBytes < 0)
 685                                 throw new ArgumentOutOfRangeException ("numBytes", "Must be >= 0");
 686
 687                         if (offset < 0)
 688                                 throw new ArgumentOutOfRangeException ("offset", "Must be >= 0");
 689
 690                         // reordered to avoid possible integer overflow
 691                         if (numBytes > array.Length - offset)
 692                                 throw new ArgumentException ("array too small. numBytes/offset wrong.");
 693
 694                         if (!async)
 695                                 return base.BeginWrite (array, offset, numBytes, userCallback, stateObject);
 696
 697                         FileStreamAsyncResult result = new FileStreamAsyncResult (userCallback, stateObject);
 698                         result.BytesRead = -1;
 699                         result.Count = numBytes;
 700                         result.OriginalCount = numBytes;
 701 /*
 702                         if (buf_dirty) {
 703                                 MemoryStream ms = new MemoryStream ();
 704                                 FlushBuffer (ms);
 705                                 ms.Write (array, offset, numBytes);
 706
 707                                 // Set arguments to new compounded buffer
 708                                 offset = 0;
 709                                 array = ms.ToArray ();
 710                                 numBytes = array.Length;
 711                         }
 712 */
 713                         WriteDelegate w = WriteInternal;
 714                         return w.BeginInvoke (array, offset, numBytes, userCallback, stateObject);
 715                 }
 716
 717                 public override void EndWrite (IAsyncResult asyncResult)
 718                 {
 719                         if (asyncResult == null)
 720                                 throw new ArgumentNullException ("asyncResult");
 721
 722                         if (!async) {
 723                                 base.EndWrite (asyncResult);
 724                                 return;
 725                         }
 726
 727                         AsyncResult ares = asyncResult as AsyncResult;
 728                         if (ares == null)
 729                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 730
 731                         WriteDelegate w = ares.AsyncDelegate as WriteDelegate;
 732                         if (w == null)
 733                                 throw new ArgumentException ("Invalid IAsyncResult", "asyncResult");
 734
 735                         w.EndInvoke (asyncResult);
 736                         return;
 737                 }
 738
 739                 public override long Seek (long offset, SeekOrigin origin)
 740                 {
 741                         long pos;
 742
 743                         if (safeHandle.IsClosed)
 744                                 throw new ObjectDisposedException ("Stream has been closed");
 745
 746                         // make absolute
 747
 748                         if(CanSeek == false) {
 749                                 throw new NotSupportedException("The stream does not support seeking");
 750                         }
 751
 752                         switch (origin) {
 753                         case SeekOrigin.End:
 754                                 pos = Length + offset;
 755                                 break;
 756
 757                         case SeekOrigin.Current:
 758                                 pos = Position + offset;
 759                                 break;
 760
 761                         case SeekOrigin.Begin:
 762                                 pos = offset;
 763                                 break;
 764
 765                         default:
 766                                 throw new ArgumentException ("origin", "Invalid SeekOrigin");
 767                         }
 768
 769                         if (pos < 0) {
 770                                 /* LAMESPEC: shouldn't this be
 771                                  * ArgumentOutOfRangeException?
 772                                  */
 773                                 throw new IOException("Attempted to Seek before the beginning of the stream");
 774                         }
 775
 776                         if(pos < this.append_startpos) {
 777                                 /* More undocumented crap */
 778                                 throw new IOException("Can't seek back over pre-existing data in append mode");
 779                         }
 780
 781                         FlushBuffer ();
 782
 783                         MonoIOError error;
 784
 785                         buf_start = MonoIO.Seek (safeHandle, pos, SeekOrigin.Begin, out error);
 786
 787                         if (error != MonoIOError.ERROR_SUCCESS) {
 788                                 // don't leak the path information for isolated storage
 789                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 790                         }
 791
 792                         return(buf_start);
 793                 }
 794
 795                 public override void SetLength (long value)
 796                 {
 797                         if (safeHandle.IsClosed)
 798                                 throw new ObjectDisposedException ("Stream has been closed");
 799
 800                         if(CanSeek == false)
 801                                 throw new NotSupportedException("The stream does not support seeking");
 802
 803                         if(CanWrite == false)
 804                                 throw new NotSupportedException("The stream does not support writing");
 805
 806                         if(value < 0)
 807                                 throw new ArgumentOutOfRangeException("value is less than 0");
 808
 809                         FlushBuffer ();
 810
 811                         MonoIOError error;
 812
 813                         MonoIO.SetLength (safeHandle, value, out error);
 814                         if (error != MonoIOError.ERROR_SUCCESS) {
 815                                 // don't leak the path information for isolated storage
 816                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 817                         }
 818
 819                         if (Position > value)
 820                                 Position = value;
 821                 }
 822
 823                 public override void Flush ()
 824                 {
 825                         if (safeHandle.IsClosed)
 826                                 throw new ObjectDisposedException ("Stream has been closed");
 827
 828                         FlushBuffer ();
 829                 }
 830
 831                 public virtual void Flush (bool flushToDisk)
 832                 {
 833                         if (safeHandle.IsClosed)
 834                                 throw new ObjectDisposedException ("Stream has been closed");
 835
 836                         FlushBuffer ();
 837
 838                         // This does the fsync
 839                         if (flushToDisk){
 840                                 MonoIOError error;
 841                                 MonoIO.Flush (safeHandle, out error);
 842                         }
 843                 }
 844
 845                 public virtual void Lock (long position, long length)
 846                 {
 847                         if (safeHandle.IsClosed)
 848                                 throw new ObjectDisposedException ("Stream has been closed");
 849                         if (position < 0) {
 850                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 851                         }
 852                         if (length < 0) {
 853                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 854                         }
 855
 856                         MonoIOError error;
 857
 858                         MonoIO.Lock (safeHandle, position, length, out error);
 859                         if (error != MonoIOError.ERROR_SUCCESS) {
 860                                 // don't leak the path information for isolated storage
 861                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 862                         }
 863                 }
 864
 865                 public virtual void Unlock (long position, long length)
 866                 {
 867                         if (safeHandle.IsClosed)
 868                                 throw new ObjectDisposedException ("Stream has been closed");
 869                         if (position < 0) {
 870                                 throw new ArgumentOutOfRangeException ("position must not be negative");
 871                         }
 872                         if (length < 0) {
 873                                 throw new ArgumentOutOfRangeException ("length must not be negative");
 874                         }
 875
 876                         MonoIOError error;
 877
 878                         MonoIO.Unlock (safeHandle, position, length, out error);
 879                         if (error != MonoIOError.ERROR_SUCCESS) {
 880                                 // don't leak the path information for isolated storage
 881                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 882                         }
 883                 }
 884
 885                 // protected
 886
 887                 ~FileStream ()
 888                 {
 889                         Dispose (false);
 890                 }
 891
 892                 protected override void Dispose (bool disposing)
 893                 {
 894                         Exception exc = null;
 895                         if (safeHandle != null && !safeHandle.IsClosed) {
 896                                 try {
 897                                         // If the FileStream is in "exposed" status
 898                                         // it means that we do not have a buffer(we write the data without buffering)
 899                                         // therefor we don't and can't flush the buffer becouse we don't have one.
 900                                         FlushBuffer ();
 901                                 } catch (Exception e) {
 902                                         exc = e;
 903                                 }
 904
 905                                 if (owner) {
 906                                         MonoIOError error;
 907
 908                                         MonoIO.Close (safeHandle.DangerousGetHandle (), out error);
 909                                         if (error != MonoIOError.ERROR_SUCCESS) {
 910                                                 // don't leak the path information for isolated storage
 911                                                 throw MonoIO.GetException (GetSecureFileName (name), error);
 912                                         }
 913
 914                                         safeHandle.DangerousRelease ();
 915                                 }
 916                         }
 917
 918                         canseek = false;
 919                         access = 0;
 920
 921                         if (disposing && buf != null) {
 922                                 if (buf.Length == DefaultBufferSize && buf_recycle == null) {
 923                                         lock (buf_recycle_lock) {
 924                                                 if (buf_recycle == null) {
 925                                                         buf_recycle = buf;
 926                                                 }
 927                                         }
 928                                 }
 929
 930                                 buf = null;
 931                                 GC.SuppressFinalize (this);
 932                         }
 933                         if (exc != null)
 934                                 throw exc;
 935                 }
 936
 937                 public FileSecurity GetAccessControl ()
 938                 {
 939                         if (safeHandle.IsClosed)
 940                                 throw new ObjectDisposedException ("Stream has been closed");
 941
 942                         return new FileSecurity (SafeFileHandle,
 943                                                  AccessControlSections.Owner |
 944                                                  AccessControlSections.Group |
 945                                                  AccessControlSections.Access);
 946                 }
 947
 948                 public void SetAccessControl (FileSecurity fileSecurity)
 949                 {
 950                         if (safeHandle.IsClosed)
 951                                 throw new ObjectDisposedException ("Stream has been closed");
 952
 953                         if (null == fileSecurity)
 954                                 throw new ArgumentNullException ("fileSecurity");
 955
 956                         fileSecurity.PersistModifications (SafeFileHandle);
 957                 }
 958
 959                 public override Task FlushAsync (CancellationToken cancellationToken)
 960                 {
 961                         if (safeHandle.IsClosed)
 962                                 throw new ObjectDisposedException ("Stream has been closed");
 963
 964                         return base.FlushAsync (cancellationToken);
 965                 }
 966
 967                 public override Task<int> ReadAsync (byte[] buffer, int offset, int count, CancellationToken cancellationToken)
 968                 {
 969                         return base.ReadAsync (buffer, offset, count, cancellationToken);
 970                 }
 971
 972                 public override Task WriteAsync (byte[] buffer, int offset, int count, CancellationToken cancellationToken)
 973                 {
 974                         return base.WriteAsync (buffer, offset, count, cancellationToken);
 975                 }
 976
 977                 // private.
 978
 979                 // ReadSegment, WriteSegment, FlushBuffer,
 980                 // RefillBuffer and ReadData should only be called
 981                 // when the Monitor lock is held, but these methods
 982                 // grab it again just to be safe.
 983
 984                 private int ReadSegment (byte [] dest, int dest_offset, int count)
 985                 {
 986                         count = Math.Min (count, buf_length - buf_offset);
 987
 988                         if (count > 0) {
 989                                 // Use the fastest method, all range checks has been done
 990                                 Buffer.InternalBlockCopy (buf, buf_offset, dest, dest_offset, count);
 991                                 buf_offset += count;
 992                         }
 993
 994                         return count;
 995                 }
 996
 997                 private int WriteSegment (byte [] src, int src_offset,
 998                                           int count)
 999                 {
1000                         if (count > buf_size - buf_offset) {
1001                                 count = buf_size - buf_offset;
1002                         }
1003
1004                         if (count > 0) {
1005                                 Buffer.BlockCopy (src, src_offset,
1006                                                   buf, buf_offset,
1007                                                   count);
1008                                 buf_offset += count;
1009                                 if (buf_offset > buf_length) {
1010                                         buf_length = buf_offset;
1011                                 }
1012
1013                                 buf_dirty = true;
1014                         }
1015
1016                         return(count);
1017                 }
1018
1019                 void FlushBuffer ()
1020                 {
1021                         if (buf_dirty) {
1022 //                              if (st == null) {
1023                                         MonoIOError error;
1024
1025                                         if (CanSeek == true && !isExposed) {
1026                                                 MonoIO.Seek (safeHandle, buf_start, SeekOrigin.Begin, out error);
1027
1028                                                 if (error != MonoIOError.ERROR_SUCCESS) {
1029                                                         // don't leak the path information for isolated storage
1030                                                         throw MonoIO.GetException (GetSecureFileName (name), error);
1031                                                 }
1032                                         }
1033
1034                                         int wcount = buf_length;
1035                                         int offset = 0;
1036                                         while (wcount > 0){
1037                                                 int n = MonoIO.Write (safeHandle, buf, offset, buf_length, out error);
1038                                                 if (error != MonoIOError.ERROR_SUCCESS) {
1039                                                         // don't leak the path information for isolated storage
1040                                                         throw MonoIO.GetException (GetSecureFileName (name), error);
1041                                                 }
1042                                                 wcount -= n;
1043                                                 offset += n;
1044                                         }
1045 //                              } else {
1046 //                                      st.Write (buf, 0, buf_length);
1047 //                              }
1048                         }
1049
1050                         buf_start += buf_offset;
1051                         buf_offset = buf_length = 0;
1052                         buf_dirty = false;
1053                 }
1054
1055                 private void FlushBufferIfDirty ()
1056                 {
1057                         if (buf_dirty)
1058                                 FlushBuffer ();
1059                 }
1060
1061                 private void RefillBuffer ()
1062                 {
1063                         FlushBuffer ();
1064
1065                         buf_length = ReadData (safeHandle, buf, 0, buf_size);
1066                 }
1067
1068                 private int ReadData (SafeHandle safeHandle, byte[] buf, int offset,
1069                                       int count)
1070                 {
1071                         MonoIOError error;
1072                         int amount = 0;
1073
1074                         /* when async == true, if we get here we don't suport AIO or it's disabled
1075                          * and we're using the threadpool */
1076                         amount = MonoIO.Read (safeHandle, buf, offset, count, out error);
1077                         if (error == MonoIOError.ERROR_BROKEN_PIPE) {
1078                                 amount = 0; // might not be needed, but well...
1079                         } else if (error != MonoIOError.ERROR_SUCCESS) {
1080                                 // don't leak the path information for isolated storage
1081                                 throw MonoIO.GetException (GetSecureFileName (name), error);
1082                         }
1083
1084                         /* Check for read error */
1085                         if(amount == -1) {
1086                                 throw new IOException ();
1087                         }
1088
1089                         return(amount);
1090                 }
1091
1092                 void InitBuffer (int size, bool isZeroSize)
1093                 {
1094                         if (isZeroSize) {
1095                                 size = 0;
1096                                 buf = new byte[1];
1097                         } else {
1098                                 if (size <= 0)
1099                                         throw new ArgumentOutOfRangeException ("bufferSize", "Positive number required.");
1100
1101                                 size = Math.Max (size, 8);
1102
1103                                 //
1104                                 // Instead of allocating a new default buffer use the
1105                                 // last one if there is any available
1106                                 //
1107                                 if (size <= DefaultBufferSize && buf_recycle != null) {
1108                                         lock (buf_recycle_lock) {
1109                                                 if (buf_recycle != null) {
1110                                                         buf = buf_recycle;
1111                                                         buf_recycle = null;
1112                                                 }
1113                                         }
1114                                 }
1115
1116                                 if (buf == null)
1117                                         buf = new byte [size];
1118                                 else
1119                                         Array.Clear (buf, 0, size);
1120                         }
1121
1122                         buf_size = size;
1123 //                      buf_start = 0;
1124 //                      buf_offset = buf_length = 0;
1125 //                      buf_dirty = false;
1126                 }
1127
1128                 private string GetSecureFileName (string filename)
1129                 {
1130                         return (anonymous) ? Path.GetFileName (filename) : Path.GetFullPath (filename);
1131                 }
1132
1133                 private string GetSecureFileName (string filename, bool full)
1134                 {
1135                         return (anonymous) ? Path.GetFileName (filename) :
1136                                 (full) ? Path.GetFullPath (filename) : filename;
1137                 }
1138
1139                 // fields
1140
1141                 internal const int DefaultBufferSize = 4096;
1142
1143                 // Input buffer ready for recycling
1144                 static byte[] buf_recycle;
1145                 static readonly object buf_recycle_lock = new object ();
1146
1147                 private byte [] buf;                    // the buffer
1148                 private string name = "[Unknown]";      // name of file.
1149
1150                 private SafeFileHandle safeHandle;
1151                 private bool isExposed;
1152
1153                 private long append_startpos;
1154
1155                 private FileAccess access;
1156                 private bool owner;
1157                 private bool async;
1158                 private bool canseek;
1159                 private bool anonymous;
1160                 private bool buf_dirty;                 // true if buffer has been written to
1161
1162                 private int buf_size;                   // capacity in bytes
1163                 private int buf_length;                 // number of valid bytes in buffer
1164                 private int buf_offset;                 // position of next byte
1165                 private long buf_start;                 // location of buffer in file
1166         }
1167 }