mcs/class/Mono.Posix/Mono.Unix/StdioFileStream.cs

   1 //
   2 // Mono.Unix/StdioFileStream.cs
   3 //
   4 // Authors:
   5 //   Jonathan Pryor (jonpryor@vt.edu)
   6 //
   7 // (C) 2005-2006 Jonathan Pryor
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.IO;
  31 using System.Runtime.InteropServices;
  32 using System.Text;
  33 using Mono.Unix;
  34
  35 namespace Mono.Unix {
  36
  37         public class StdioFileStream : Stream
  38         {
  39                 public static readonly IntPtr InvalidFileStream  = IntPtr.Zero;
  40                 public static readonly IntPtr StandardInput  = Native.Stdlib.stdin;
  41                 public static readonly IntPtr StandardOutput = Native.Stdlib.stdout;
  42                 public static readonly IntPtr StandardError  = Native.Stdlib.stderr;
  43
  44                 public StdioFileStream (IntPtr fileStream)
  45                         : this (fileStream, true) {}
  46
  47                 public StdioFileStream (IntPtr fileStream, bool ownsHandle)
  48                 {
  49                         InitStream (fileStream, ownsHandle);
  50                 }
  51
  52                 public StdioFileStream (IntPtr fileStream, FileAccess access)
  53                         : this (fileStream, access, true) {}
  54
  55                 public StdioFileStream (IntPtr fileStream, FileAccess access, bool ownsHandle)
  56                 {
  57                         InitStream (fileStream, ownsHandle);
  58                         InitCanReadWrite (access);
  59                 }
  60
  61                 public StdioFileStream (string path)
  62                 {
  63                         if (path == null)
  64                                 throw new ArgumentNullException ("path");
  65                         InitStream (Fopen (path, "rb"), true);
  66                 }
  67
  68                 public StdioFileStream (string path, string mode)
  69                 {
  70                         if (path == null)
  71                                 throw new ArgumentNullException ("path");
  72                         InitStream (Fopen (path, mode), true);
  73                 }
  74
  75                 public StdioFileStream (string path, FileMode mode)
  76                 {
  77                         if (path == null)
  78                                 throw new ArgumentNullException ("path");
  79                         InitStream (Fopen (path, ToFopenMode (path, mode)), true);
  80                 }
  81
  82                 public StdioFileStream (string path, FileAccess access)
  83                 {
  84                         if (path == null)
  85                                 throw new ArgumentNullException ("path");
  86                         InitStream (Fopen (path, ToFopenMode (path, access)), true);
  87                         InitCanReadWrite (access);
  88                 }
  89
  90                 public StdioFileStream (string path, FileMode mode, FileAccess access)
  91                 {
  92                         if (path == null)
  93                                 throw new ArgumentNullException ("path");
  94                         InitStream (Fopen (path, ToFopenMode (path, mode, access)), true);
  95                         InitCanReadWrite (access);
  96                 }
  97
  98                 private static IntPtr Fopen (string path, string mode)
  99                 {
 100                         if (path.Length == 0)
 101                                 throw new ArgumentException ("path");
 102                         if (mode == null)
 103                                 throw new ArgumentNullException ("mode");
 104                         IntPtr f = Native.Stdlib.fopen (path, mode);
 105                         if (f == IntPtr.Zero)
 106                                 throw new DirectoryNotFoundException ("path",
 107                                                 UnixMarshal.CreateExceptionForLastError ());
 108                         return f;
 109                 }
 110
 111                 private void InitStream (IntPtr fileStream, bool ownsHandle)
 112                 {
 113                         if (InvalidFileStream == fileStream)
 114                                 throw new ArgumentException (Locale.GetText ("Invalid file stream"), "fileStream");
 115
 116                         this.file = fileStream;
 117                         this.owner = ownsHandle;
 118
 119                         try {
 120                                 long offset = Native.Stdlib.fseek (file, 0, Native.SeekFlags.SEEK_CUR);
 121                                 if (offset != -1)
 122                                         canSeek = true;
 123                                 Native.Stdlib.fread (IntPtr.Zero, 0, 0, file);
 124                                 if (Native.Stdlib.ferror (file) == 0)
 125                                         canRead = true;
 126                                 Native.Stdlib.fwrite (IntPtr.Zero, 0, 0, file);
 127                                 if (Native.Stdlib.ferror (file) == 0)
 128                                         canWrite = true;
 129                                 Native.Stdlib.clearerr (file);
 130                         }
 131                         catch (Exception) {
 132                                 throw new ArgumentException (Locale.GetText ("Invalid file stream"), "fileStream");
 133                         }
 134                         GC.KeepAlive (this);
 135                 }
 136
 137                 private void InitCanReadWrite (FileAccess access)
 138                 {
 139                         canRead = canRead &&
 140                                 (access == FileAccess.Read || access == FileAccess.ReadWrite);
 141                         canWrite = canWrite &&
 142                                 (access == FileAccess.Write || access == FileAccess.ReadWrite);
 143                 }
 144
 145                 private static string ToFopenMode (string file, FileMode mode)
 146                 {
 147                         string cmode = Native.NativeConvert.ToFopenMode (mode);
 148                         AssertFileMode (file, mode);
 149                         return cmode;
 150                 }
 151
 152                 private static string ToFopenMode (string file, FileAccess access)
 153                 {
 154                         return Native.NativeConvert.ToFopenMode (access);
 155                 }
 156
 157                 private static string ToFopenMode (string file, FileMode mode, FileAccess access)
 158                 {
 159                         string cmode = Native.NativeConvert.ToFopenMode (mode, access);
 160                         bool exists = AssertFileMode (file, mode);
 161                         // HACK: for open-or-create & read, mode is "rb", which doesn't create
 162                         // files.  If the file doesn't exist, we need to use "w+b" to ensure
 163                         // file creation.
 164                         if (mode == FileMode.OpenOrCreate && access == FileAccess.Read && !exists)
 165                                 cmode = "w+b";
 166                         return cmode;
 167                 }
 168
 169                 private static bool AssertFileMode (string file, FileMode mode)
 170                 {
 171                         bool exists = FileExists (file);
 172                         if (mode == FileMode.CreateNew && exists)
 173                                 throw new IOException ("File exists and FileMode.CreateNew specified");
 174                         if ((mode == FileMode.Open || mode == FileMode.Truncate) && !exists)
 175                                 throw new FileNotFoundException ("File doesn't exist and FileMode.Open specified", file);
 176                         return exists;
 177                 }
 178
 179                 private static bool FileExists (string file)
 180                 {
 181                         bool found = false;
 182                         IntPtr f = Native.Stdlib.fopen (file, "r");
 183                         found = f != IntPtr.Zero;
 184                         if (f != IntPtr.Zero)
 185                                 Native.Stdlib.fclose (f);
 186                         return found;
 187                 }
 188
 189                 private void AssertNotDisposed ()
 190                 {
 191                         if (file == InvalidFileStream)
 192                                 throw new ObjectDisposedException ("Invalid File Stream");
 193                         GC.KeepAlive (this);
 194                 }
 195
 196                 public IntPtr Handle {
 197                         get {
 198                                 AssertNotDisposed ();
 199                                 GC.KeepAlive (this);
 200                                 return file;
 201                         }
 202                 }
 203
 204                 public override bool CanRead {
 205                         get {return canRead;}
 206                 }
 207
 208                 public override bool CanSeek {
 209                         get {return canSeek;}
 210                 }
 211
 212                 public override bool CanWrite {
 213                         get {return canWrite;}
 214                 }
 215
 216                 public override long Length {
 217                         get {
 218                                 AssertNotDisposed ();
 219                                 if (!CanSeek)
 220                                         throw new NotSupportedException ("File Stream doesn't support seeking");
 221                                 long curPos = Native.Stdlib.ftell (file);
 222                                 if (curPos == -1)
 223                                         throw new NotSupportedException ("Unable to obtain current file position");
 224                                 int r = Native.Stdlib.fseek (file, 0, Native.SeekFlags.SEEK_END);
 225                                 UnixMarshal.ThrowExceptionForLastErrorIf (r);
 226
 227                                 long endPos = Native.Stdlib.ftell (file);
 228                                 if (endPos == -1)
 229                                         UnixMarshal.ThrowExceptionForLastError ();
 230
 231                                 r = Native.Stdlib.fseek (file, curPos, Native.SeekFlags.SEEK_SET);
 232                                 UnixMarshal.ThrowExceptionForLastErrorIf (r);
 233
 234                                 GC.KeepAlive (this);
 235                                 return endPos;
 236                         }
 237                 }
 238
 239                 public override long Position {
 240                         get {
 241                                 AssertNotDisposed ();
 242                                 if (!CanSeek)
 243                                         throw new NotSupportedException ("The stream does not support seeking");
 244                                 long pos = Native.Stdlib.ftell (file);
 245                                 if (pos == -1)
 246                                         UnixMarshal.ThrowExceptionForLastError ();
 247                                 GC.KeepAlive (this);
 248                                 return (long) pos;
 249                         }
 250                         set {
 251                                 AssertNotDisposed ();
 252                                 Seek (value, SeekOrigin.Begin);
 253                         }
 254                 }
 255
 256                 public void SaveFilePosition (Native.FilePosition pos)
 257                 {
 258                         AssertNotDisposed ();
 259                         int r = Native.Stdlib.fgetpos (file, pos);
 260                         UnixMarshal.ThrowExceptionForLastErrorIf (r);
 261                         GC.KeepAlive (this);
 262                 }
 263
 264                 public void RestoreFilePosition (Native.FilePosition pos)
 265                 {
 266                         AssertNotDisposed ();
 267                         if (pos == null)
 268                                 throw new ArgumentNullException ("value");
 269                         int r = Native.Stdlib.fsetpos (file, pos);
 270                         UnixMarshal.ThrowExceptionForLastErrorIf (r);
 271                         GC.KeepAlive (this);
 272                 }
 273
 274                 public override void Flush ()
 275                 {
 276                         AssertNotDisposed ();
 277                         int r = Native.Stdlib.fflush (file);
 278                         if (r != 0)
 279                                 UnixMarshal.ThrowExceptionForLastError ();
 280                         GC.KeepAlive (this);
 281                 }
 282
 283                 public override unsafe int Read ([In, Out] byte[] buffer, int offset, int count)
 284                 {
 285                         AssertNotDisposed ();
 286                         AssertValidBuffer (buffer, offset, count);
 287                         if (!CanRead)
 288                                 throw new NotSupportedException ("Stream does not support reading");
 289
 290                         ulong r = 0;
 291                         fixed (byte* buf = &buffer[offset]) {
 292                                 r = Native.Stdlib.fread (buf, 1, (ulong) count, file);
 293                         }
 294                         if (r != (ulong) count) {
 295                                 if (Native.Stdlib.ferror (file) != 0)
 296                                         throw new IOException ();
 297                         }
 298                         GC.KeepAlive (this);
 299                         return (int) r;
 300                 }
 301
 302                 private void AssertValidBuffer (byte[] buffer, int offset, int count)
 303                 {
 304                         if (buffer == null)
 305                                 throw new ArgumentNullException ("buffer");
 306                         if (offset < 0)
 307                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
 308                         if (count < 0)
 309                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 310                         if (offset > buffer.Length)
 311                                 throw new ArgumentException ("destination offset is beyond array size");
 312                         if (offset > (buffer.Length - count))
 313                                 throw new ArgumentException ("would overrun buffer");
 314                 }
 315
 316                 public void Rewind ()
 317                 {
 318                         AssertNotDisposed ();
 319                         Native.Stdlib.rewind (file);
 320                         GC.KeepAlive (this);
 321                 }
 322
 323                 public override long Seek (long offset, SeekOrigin origin)
 324                 {
 325                         AssertNotDisposed ();
 326                         if (!CanSeek)
 327                                 throw new NotSupportedException ("The File Stream does not support seeking");
 328
 329                         Native.SeekFlags sf = Native.SeekFlags.SEEK_CUR;
 330                         switch (origin) {
 331                                 case SeekOrigin.Begin:   sf = Native.SeekFlags.SEEK_SET; break;
 332                                 case SeekOrigin.Current: sf = Native.SeekFlags.SEEK_CUR; break;
 333                                 case SeekOrigin.End:     sf = Native.SeekFlags.SEEK_END; break;
 334                                 default: throw new ArgumentException ("origin");
 335                         }
 336
 337                         int r = Native.Stdlib.fseek (file, offset, sf);
 338                         if (r != 0)
 339                                 throw new IOException ("Unable to seek",
 340                                                 UnixMarshal.CreateExceptionForLastError ());
 341
 342                         long pos = Native.Stdlib.ftell (file);
 343                         if (pos == -1)
 344                                 throw new IOException ("Unable to get current file position",
 345                                                 UnixMarshal.CreateExceptionForLastError ());
 346
 347                         GC.KeepAlive (this);
 348                         return pos;
 349                 }
 350
 351                 public override void SetLength (long value)
 352                 {
 353                         throw new NotSupportedException ("ANSI C doesn't provide a way to truncate a file");
 354                 }
 355
 356                 public override unsafe void Write (byte[] buffer, int offset, int count)
 357                 {
 358                         AssertNotDisposed ();
 359                         AssertValidBuffer (buffer, offset, count);
 360                         if (!CanWrite)
 361                                 throw new NotSupportedException ("File Stream does not support writing");
 362
 363                         ulong r = 0;
 364                         fixed (byte* buf = &buffer[offset]) {
 365                                 r = Native.Stdlib.fwrite (buf, (ulong) 1, (ulong) count, file);
 366                         }
 367                         if (r != (ulong) count)
 368                                 UnixMarshal.ThrowExceptionForLastError ();
 369                         GC.KeepAlive (this);
 370                 }
 371
 372                 ~StdioFileStream ()
 373                 {
 374                         Close ();
 375                 }
 376
 377                 public override void Close ()
 378                 {
 379                         if (file == InvalidFileStream)
 380                                 return;
 381
 382                         if (owner) {
 383                                 int r = Native.Stdlib.fclose (file);
 384                                 if (r != 0)
 385                                         UnixMarshal.ThrowExceptionForLastError ();
 386                         } else
 387                                 Flush ();
 388
 389                         file = InvalidFileStream;
 390                         canRead = false;
 391                         canSeek = false;
 392                         canWrite = false;
 393
 394                         GC.SuppressFinalize (this);
 395                         GC.KeepAlive (this);
 396                 }
 397
 398                 private bool canSeek  = false;
 399                 private bool canRead  = false;
 400                 private bool canWrite = false;
 401                 private bool owner    = true;
 402                 private IntPtr file   = InvalidFileStream;
 403         }
 404 }
 405
 406 // vim: noexpandtab