src/common/file.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        file.cpp
   3 // Purpose:     wxFile - encapsulates low-level "file descriptor"
   4 //              wxTempFile
   5 // Author:      Vadim Zeitlin
   6 // Modified by:
   7 // Created:     29/01/98
   8 // RCS-ID:      $Id$
   9 // Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
  10 // Licence:     wxWindows licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 // ----------------------------------------------------------------------------
  14 // headers
  15 // ----------------------------------------------------------------------------
  16
  17 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  18     #pragma implementation "file.h"
  19 #endif
  20
  21 // For compilers that support precompilation, includes "wx.h".
  22 #include "wx/wxprec.h"
  23
  24 #ifdef __BORLANDC__
  25   #pragma hdrstop
  26 #endif
  27
  28 #if wxUSE_FILE
  29
  30 // standard
  31 #if defined(__WXMSW__) && !defined(__GNUWIN32__) && !defined(__WXMICROWIN__) && !defined(__WXWINCE__)
  32
  33 #ifndef __SALFORDC__
  34     #define   WIN32_LEAN_AND_MEAN
  35     #define   NOSERVICE
  36     #define   NOIME
  37     #define   NOATOM
  38     #define   NOGDI
  39     #define   NOGDICAPMASKS
  40     #define   NOMETAFILE
  41     #define   NOMINMAX
  42     #define   NOMSG
  43     #define   NOOPENFILE
  44     #define   NORASTEROPS
  45     #define   NOSCROLL
  46     #define   NOSOUND
  47     #define   NOSYSMETRICS
  48     #define   NOTEXTMETRIC
  49     #define   NOWH
  50     #define   NOCOMM
  51     #define   NOKANJI
  52     #define   NOCRYPT
  53     #define   NOMCX
  54 #endif
  55
  56 #elif defined(__WXMSW__) && defined(__WXWINCE__)
  57     #include  "wx/msw/missing.h"
  58 #elif (defined(__OS2__))
  59     #include <io.h>
  60 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  61     #include  <unistd.h>
  62     #include  <time.h>
  63     #include  <sys/stat.h>
  64     #ifdef __GNUWIN32__
  65         #include "wx/msw/wrapwin.h"
  66     #endif
  67 #elif defined(__DOS__)
  68     #if defined(__WATCOMC__)
  69        #include <io.h>
  70     #elif defined(__DJGPP__)
  71        #include <io.h>
  72        #include <unistd.h>
  73        #include <stdio.h>
  74     #else
  75         #error  "Please specify the header with file functions declarations."
  76     #endif
  77 #elif (defined(__WXSTUBS__))
  78     // Have to ifdef this for different environments
  79     #include <io.h>
  80 #elif (defined(__WXMAC__))
  81 #if __MSL__ < 0x6000
  82     int access( const char *path, int mode ) { return 0 ; }
  83 #else
  84     int _access( const char *path, int mode ) { return 0 ; }
  85 #endif
  86     char* mktemp( char * path ) { return path ;}
  87     #include <stat.h>
  88     #include <unistd.h>
  89 #else
  90     #error  "Please specify the header with file functions declarations."
  91 #endif  //Win/UNIX
  92
  93 #include  <stdio.h>       // SEEK_xxx constants
  94
  95 // Windows compilers don't have these constants
  96 #ifndef W_OK
  97     enum
  98     {
  99         F_OK = 0,   // test for existence
 100         X_OK = 1,   //          execute permission
 101         W_OK = 2,   //          write
 102         R_OK = 4    //          read
 103     };
 104 #endif // W_OK
 105
 106 // there is no distinction between text and binary files under Unix, so define
 107 // O_BINARY as 0 if the system headers don't do it already
 108 #if defined(__UNIX__) && !defined(O_BINARY)
 109     #define   O_BINARY    (0)
 110 #endif  //__UNIX__
 111
 112 #ifdef __SALFORDC__
 113     #include <unix.h>
 114 #endif
 115
 116 #ifndef MAX_PATH
 117     #define MAX_PATH 512
 118 #endif
 119
 120 // some broken compilers don't have 3rd argument in open() and creat()
 121 #ifdef __SALFORDC__
 122     #define ACCESS(access)
 123     #define stat    _stat
 124 #else // normal compiler
 125     #define ACCESS(access)  , (access)
 126 #endif // Salford C
 127
 128 // wxWidgets
 129 #ifndef WX_PRECOMP
 130     #include  "wx/string.h"
 131     #include  "wx/intl.h"
 132     #include  "wx/log.h"
 133 #endif // !WX_PRECOMP
 134
 135 #include  "wx/filename.h"
 136 #include  "wx/file.h"
 137 #include  "wx/filefn.h"
 138
 139 #ifdef __WXMSW__
 140     #include "wx/msw/mslu.h"
 141 #endif
 142
 143 #ifdef __WXWINCE__
 144     #include "wx/msw/private.h"
 145 #endif
 146
 147 #if !defined __UNIX__ && !defined __DJGPP__
 148     #ifdef __WXWINCE__
 149         typedef int ssize_t;
 150     #else
 151         typedef ptrdiff_t ssize_t;
 152     #endif
 153 #endif
 154 wxCOMPILE_TIME_ASSERT(sizeof(ssize_t) == sizeof(size_t), ssize_t_wrong_size);
 155
 156 // ============================================================================
 157 // implementation of wxFile
 158 // ============================================================================
 159
 160 // ----------------------------------------------------------------------------
 161 // static functions
 162 // ----------------------------------------------------------------------------
 163
 164 bool wxFile::Exists(const wxChar *name)
 165 {
 166     return wxFileExists(name);
 167 }
 168
 169 bool wxFile::Access(const wxChar *name, OpenMode mode)
 170 {
 171     int how;
 172
 173     switch ( mode )
 174     {
 175         default:
 176             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 177             // fall through
 178
 179         case read:
 180             how = R_OK;
 181             break;
 182
 183         case write:
 184             how = W_OK;
 185             break;
 186
 187         case read_write:
 188             how = R_OK | W_OK;
 189             break;
 190     }
 191
 192     return wxAccess(name, how) == 0;
 193 }
 194
 195 // ----------------------------------------------------------------------------
 196 // opening/closing
 197 // ----------------------------------------------------------------------------
 198
 199 // ctors
 200 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 201 {
 202     m_fd = fd_invalid;
 203     m_error = false;
 204
 205     Open(szFileName, mode);
 206 }
 207
 208 // create the file, fail if it already exists and bOverwrite
 209 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 210 {
 211     // if bOverwrite we create a new file or truncate the existing one,
 212     // otherwise we only create the new file and fail if it already exists
 213 #if defined(__WXMAC__) && !defined(__UNIX__) && !wxUSE_UNICODE
 214     // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
 215     // int fd = open( szFileName , O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 216     int fd = creat( szFileName , accessMode);
 217 #else
 218     int fd = wxOpen( szFileName,
 219                      O_BINARY | O_WRONLY | O_CREAT |
 220                      (bOverwrite ? O_TRUNC : O_EXCL)
 221                      ACCESS(accessMode) );
 222 #endif
 223     if ( fd == -1 )
 224     {
 225         wxLogSysError(_("can't create file '%s'"), szFileName);
 226         return false;
 227     }
 228     else
 229     {
 230         Attach(fd);
 231         return true;
 232     }
 233 }
 234
 235 // open the file
 236 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 237 {
 238     int flags = O_BINARY;
 239
 240     switch ( mode )
 241     {
 242         case read:
 243             flags |= O_RDONLY;
 244             break;
 245
 246         case write_append:
 247             if ( wxFile::Exists(szFileName) )
 248             {
 249                 flags |= O_WRONLY | O_APPEND;
 250                 break;
 251             }
 252             //else: fall through as write_append is the same as write if the
 253             //      file doesn't exist
 254
 255         case write:
 256             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 257             break;
 258
 259         case write_excl:
 260             flags |= O_WRONLY | O_CREAT | O_EXCL;
 261             break;
 262
 263         case read_write:
 264             flags |= O_RDWR;
 265             break;
 266     }
 267
 268 #ifdef __WINDOWS__
 269     // only read/write bits for "all" are supported by this function under
 270     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 271     // accessMode, so clear them as they have at best no effect anyhow
 272     accessMode &= wxS_IRUSR | wxS_IWUSR;
 273 #endif // __WINDOWS__
 274
 275     int fd = wxOpen( szFileName, flags ACCESS(accessMode));
 276
 277     if ( fd == -1 )
 278     {
 279         wxLogSysError(_("can't open file '%s'"), szFileName);
 280         return false;
 281     }
 282     else {
 283         Attach(fd);
 284         return true;
 285     }
 286 }
 287
 288 // close
 289 bool wxFile::Close()
 290 {
 291     if ( IsOpened() ) {
 292         if (wxClose(m_fd) == -1)
 293         {
 294             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 295             m_fd = fd_invalid;
 296             return false;
 297         }
 298         else
 299             m_fd = fd_invalid;
 300     }
 301
 302     return true;
 303 }
 304
 305 // ----------------------------------------------------------------------------
 306 // read/write
 307 // ----------------------------------------------------------------------------
 308
 309 // read
 310 size_t wxFile::Read(void *pBuf, size_t nCount)
 311 {
 312     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 313
 314     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 315
 316     if ( iRc == -1 )
 317     {
 318         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 319         return (size_t)wxInvalidOffset;
 320     }
 321
 322     return iRc;
 323 }
 324
 325 // write
 326 size_t wxFile::Write(const void *pBuf, size_t nCount)
 327 {
 328     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 329
 330     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 331
 332     if ( iRc == -1 )
 333     {
 334         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 335         m_error = true;
 336         iRc = 0;
 337     }
 338
 339     return iRc;
 340 }
 341
 342 // flush
 343 bool wxFile::Flush()
 344 {
 345     if ( IsOpened() ) {
 346 #if defined(__VISUALC__) || wxHAVE_FSYNC
 347         if ( wxFsync(m_fd) == -1 )
 348         {
 349             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 350             return false;
 351         }
 352 #else // no fsync
 353         // just do nothing
 354 #endif // fsync
 355     }
 356
 357     return true;
 358 }
 359
 360 // ----------------------------------------------------------------------------
 361 // seek
 362 // ----------------------------------------------------------------------------
 363
 364 // seek
 365 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 366 {
 367     wxASSERT( IsOpened() );
 368
 369     int origin;
 370     switch ( mode ) {
 371         default:
 372             wxFAIL_MSG(_("unknown seek origin"));
 373
 374         case wxFromStart:
 375             origin = SEEK_SET;
 376             break;
 377
 378         case wxFromCurrent:
 379             origin = SEEK_CUR;
 380             break;
 381
 382         case wxFromEnd:
 383             origin = SEEK_END;
 384             break;
 385     }
 386
 387     if (ofs == wxInvalidOffset)
 388     {
 389         wxLogSysError(_("can't seek on file descriptor %d, large files support is not enabled."), m_fd);
 390         return wxInvalidOffset;
 391     }
 392     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 393     if ( iRc == wxInvalidOffset )
 394     {
 395         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 396     }
 397
 398     return iRc;
 399 }
 400
 401 // get current file offset
 402 wxFileOffset wxFile::Tell() const
 403 {
 404     wxASSERT( IsOpened() );
 405
 406     wxFileOffset iRc = wxTell(m_fd);
 407     if ( iRc == wxInvalidOffset )
 408     {
 409         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 410     }
 411
 412     return iRc;
 413 }
 414
 415 // get current file length
 416 wxFileOffset wxFile::Length() const
 417 {
 418     wxASSERT( IsOpened() );
 419
 420     wxFileOffset iRc = Tell();
 421     if ( iRc != wxInvalidOffset ) {
 422         // have to use const_cast :-(
 423         wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
 424         if ( iLen != wxInvalidOffset ) {
 425             // restore old position
 426             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 427                 // error
 428                 iLen = wxInvalidOffset;
 429             }
 430         }
 431
 432         iRc = iLen;
 433     }
 434
 435     if ( iRc == wxInvalidOffset )
 436     {
 437         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 438     }
 439
 440     return iRc;
 441 }
 442
 443 // is end of file reached?
 444 bool wxFile::Eof() const
 445 {
 446     wxASSERT( IsOpened() );
 447
 448     wxFileOffset iRc;
 449
 450 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 451     // @@ this doesn't work, of course, on unseekable file descriptors
 452     wxFileOffset ofsCur = Tell(),
 453     ofsMax = Length();
 454     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 455         iRc = wxInvalidOffset;
 456     else
 457         iRc = ofsCur == ofsMax;
 458 #else  // Windows and "native" compiler
 459     iRc = wxEof(m_fd);
 460 #endif // Windows/Unix
 461
 462     if ( iRc == 1)
 463         {}
 464     else if ( iRc == 0 )
 465         return false;
 466     else if ( iRc == wxInvalidOffset )
 467         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 468     else
 469         wxFAIL_MSG(_("invalid eof() return value."));
 470
 471     return true;
 472 }
 473
 474 // ============================================================================
 475 // implementation of wxTempFile
 476 // ============================================================================
 477
 478 // ----------------------------------------------------------------------------
 479 // construction
 480 // ----------------------------------------------------------------------------
 481
 482 wxTempFile::wxTempFile(const wxString& strName)
 483 {
 484     Open(strName);
 485 }
 486
 487 bool wxTempFile::Open(const wxString& strName)
 488 {
 489     // we must have an absolute filename because otherwise CreateTempFileName()
 490     // would create the temp file in $TMP (i.e. the system standard location
 491     // for the temp files) which might be on another volume/drive/mount and
 492     // wxRename()ing it later to m_strName from Commit() would then fail
 493     //
 494     // with the absolute filename, the temp file is created in the same
 495     // directory as this one which ensures that wxRename() may work later
 496     wxFileName fn(strName);
 497     if ( !fn.IsAbsolute() )
 498     {
 499         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 500     }
 501
 502     m_strName = fn.GetFullPath();
 503
 504     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 505
 506     if ( m_strTemp.empty() )
 507     {
 508         // CreateTempFileName() failed
 509         return false;
 510     }
 511
 512 #ifdef __UNIX__
 513     // the temp file should have the same permissions as the original one
 514     mode_t mode;
 515
 516     wxStructStat st;
 517     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 518     {
 519         mode = st.st_mode;
 520     }
 521     else
 522     {
 523         // file probably didn't exist, just give it the default mode _using_
 524         // user's umask (new files creation should respect umask)
 525         mode_t mask = umask(0777);
 526         mode = 0666 & ~mask;
 527         umask(mask);
 528     }
 529
 530     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 531     {
 532 #ifndef __OS2__
 533         wxLogSysError(_("Failed to set temporary file permissions"));
 534 #endif
 535     }
 536 #endif // Unix
 537
 538     return true;
 539 }
 540
 541 // ----------------------------------------------------------------------------
 542 // destruction
 543 // ----------------------------------------------------------------------------
 544
 545 wxTempFile::~wxTempFile()
 546 {
 547     if ( IsOpened() )
 548         Discard();
 549 }
 550
 551 bool wxTempFile::Commit()
 552 {
 553     m_file.Close();
 554
 555     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 556         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 557         return false;
 558     }
 559
 560     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 561         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 562         return false;
 563     }
 564
 565     return true;
 566 }
 567
 568 void wxTempFile::Discard()
 569 {
 570     m_file.Close();
 571     if ( wxRemove(m_strTemp) != 0 )
 572         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 573 }
 574
 575 #endif // wxUSE_FILE
 576