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
 148 // ============================================================================
 149 // implementation of wxFile
 150 // ============================================================================
 151
 152 // ----------------------------------------------------------------------------
 153 // static functions
 154 // ----------------------------------------------------------------------------
 155
 156 bool wxFile::Exists(const wxChar *name)
 157 {
 158     return wxFileExists(name);
 159 }
 160
 161 bool wxFile::Access(const wxChar *name, OpenMode mode)
 162 {
 163     int how;
 164
 165     switch ( mode )
 166     {
 167         default:
 168             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 169             // fall through
 170
 171         case read:
 172             how = R_OK;
 173             break;
 174
 175         case write:
 176             how = W_OK;
 177             break;
 178
 179         case read_write:
 180             how = R_OK | W_OK;
 181             break;
 182     }
 183
 184     return wxAccess(name, how) == 0;
 185 }
 186
 187 // ----------------------------------------------------------------------------
 188 // opening/closing
 189 // ----------------------------------------------------------------------------
 190
 191 // ctors
 192 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 193 {
 194     m_fd = fd_invalid;
 195     m_error = false;
 196
 197     Open(szFileName, mode);
 198 }
 199
 200 // create the file, fail if it already exists and bOverwrite
 201 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 202 {
 203     // if bOverwrite we create a new file or truncate the existing one,
 204     // otherwise we only create the new file and fail if it already exists
 205 #if defined(__WXMAC__) && !defined(__UNIX__) && !wxUSE_UNICODE
 206     // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
 207     // int fd = open( szFileName , O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 208     int fd = creat( szFileName , accessMode);
 209 #else
 210     int fd = wxOpen( szFileName,
 211                      O_BINARY | O_WRONLY | O_CREAT |
 212                      (bOverwrite ? O_TRUNC : O_EXCL)
 213                      ACCESS(accessMode) );
 214 #endif
 215     if ( fd == -1 )
 216     {
 217         wxLogSysError(_("can't create file '%s'"), szFileName);
 218         return false;
 219     }
 220     else
 221     {
 222         Attach(fd);
 223         return true;
 224     }
 225 }
 226
 227 // open the file
 228 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 229 {
 230     int flags = O_BINARY;
 231
 232     switch ( mode )
 233     {
 234         case read:
 235             flags |= O_RDONLY;
 236             break;
 237
 238         case write_append:
 239             if ( wxFile::Exists(szFileName) )
 240             {
 241                 flags |= O_WRONLY | O_APPEND;
 242                 break;
 243             }
 244             //else: fall through as write_append is the same as write if the
 245             //      file doesn't exist
 246
 247         case write:
 248             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 249             break;
 250
 251         case write_excl:
 252             flags |= O_WRONLY | O_CREAT | O_EXCL;
 253             break;
 254
 255         case read_write:
 256             flags |= O_RDWR;
 257             break;
 258     }
 259
 260 #ifdef __WINDOWS__
 261     // only read/write bits for "all" are supported by this function under
 262     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 263     // accessMode, so clear them as they have at best no effect anyhow
 264     accessMode &= wxS_IRUSR | wxS_IWUSR;
 265 #endif // __WINDOWS__
 266
 267     int fd = wxOpen( szFileName, flags ACCESS(accessMode));
 268
 269     if ( fd == -1 )
 270     {
 271         wxLogSysError(_("can't open file '%s'"), szFileName);
 272         return false;
 273     }
 274     else {
 275         Attach(fd);
 276         return true;
 277     }
 278 }
 279
 280 // close
 281 bool wxFile::Close()
 282 {
 283     if ( IsOpened() ) {
 284         if (wxClose(m_fd) == -1)
 285         {
 286             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 287             m_fd = fd_invalid;
 288             return false;
 289         }
 290         else
 291             m_fd = fd_invalid;
 292     }
 293
 294     return true;
 295 }
 296
 297 // ----------------------------------------------------------------------------
 298 // read/write
 299 // ----------------------------------------------------------------------------
 300
 301 // read
 302 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 303 {
 304     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 305
 306     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 307
 308     if ( iRc == -1 )
 309     {
 310         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 311         return wxInvalidOffset;
 312     }
 313
 314     return iRc;
 315 }
 316
 317 // write
 318 size_t wxFile::Write(const void *pBuf, size_t nCount)
 319 {
 320     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 321
 322     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 323
 324     if ( iRc == -1 )
 325     {
 326         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 327         m_error = true;
 328         iRc = 0;
 329     }
 330
 331     return iRc;
 332 }
 333
 334 // flush
 335 bool wxFile::Flush()
 336 {
 337 #if defined(__VISUALC__) || defined(HAVE_FSYNC)
 338     // fsync() only works on disk files and returns errors for pipes, don't
 339     // call it then
 340     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 341     {
 342         if ( wxFsync(m_fd) == -1 )
 343         {
 344             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 345             return false;
 346         }
 347     }
 348 #endif // fsync
 349
 350     return true;
 351 }
 352
 353 // ----------------------------------------------------------------------------
 354 // seek
 355 // ----------------------------------------------------------------------------
 356
 357 // seek
 358 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 359 {
 360     wxASSERT_MSG( IsOpened(), _T("can't seek on closed file") );
 361     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 362                  wxInvalidOffset,
 363                  _T("invalid absolute file offset") );
 364
 365     int origin;
 366     switch ( mode ) {
 367         default:
 368             wxFAIL_MSG(_("unknown seek origin"));
 369
 370         case wxFromStart:
 371             origin = SEEK_SET;
 372             break;
 373
 374         case wxFromCurrent:
 375             origin = SEEK_CUR;
 376             break;
 377
 378         case wxFromEnd:
 379             origin = SEEK_END;
 380             break;
 381     }
 382
 383     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 384     if ( iRc == wxInvalidOffset )
 385     {
 386         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 387     }
 388
 389     return iRc;
 390 }
 391
 392 // get current file offset
 393 wxFileOffset wxFile::Tell() const
 394 {
 395     wxASSERT( IsOpened() );
 396
 397     wxFileOffset iRc = wxTell(m_fd);
 398     if ( iRc == wxInvalidOffset )
 399     {
 400         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 401     }
 402
 403     return iRc;
 404 }
 405
 406 // get current file length
 407 wxFileOffset wxFile::Length() const
 408 {
 409     wxASSERT( IsOpened() );
 410
 411     wxFileOffset iRc = Tell();
 412     if ( iRc != wxInvalidOffset ) {
 413         // have to use const_cast :-(
 414         wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
 415         if ( iLen != wxInvalidOffset ) {
 416             // restore old position
 417             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 418                 // error
 419                 iLen = wxInvalidOffset;
 420             }
 421         }
 422
 423         iRc = iLen;
 424     }
 425
 426     if ( iRc == wxInvalidOffset )
 427     {
 428         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 429     }
 430
 431     return iRc;
 432 }
 433
 434 // is end of file reached?
 435 bool wxFile::Eof() const
 436 {
 437     wxASSERT( IsOpened() );
 438
 439     wxFileOffset iRc;
 440
 441 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 442     // @@ this doesn't work, of course, on unseekable file descriptors
 443     wxFileOffset ofsCur = Tell(),
 444     ofsMax = Length();
 445     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 446         iRc = wxInvalidOffset;
 447     else
 448         iRc = ofsCur == ofsMax;
 449 #else  // Windows and "native" compiler
 450     iRc = wxEof(m_fd);
 451 #endif // Windows/Unix
 452
 453     if ( iRc == 1)
 454         {}
 455     else if ( iRc == 0 )
 456         return false;
 457     else if ( iRc == wxInvalidOffset )
 458         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 459     else
 460         wxFAIL_MSG(_("invalid eof() return value."));
 461
 462     return true;
 463 }
 464
 465 // ============================================================================
 466 // implementation of wxTempFile
 467 // ============================================================================
 468
 469 // ----------------------------------------------------------------------------
 470 // construction
 471 // ----------------------------------------------------------------------------
 472
 473 wxTempFile::wxTempFile(const wxString& strName)
 474 {
 475     Open(strName);
 476 }
 477
 478 bool wxTempFile::Open(const wxString& strName)
 479 {
 480     // we must have an absolute filename because otherwise CreateTempFileName()
 481     // would create the temp file in $TMP (i.e. the system standard location
 482     // for the temp files) which might be on another volume/drive/mount and
 483     // wxRename()ing it later to m_strName from Commit() would then fail
 484     //
 485     // with the absolute filename, the temp file is created in the same
 486     // directory as this one which ensures that wxRename() may work later
 487     wxFileName fn(strName);
 488     if ( !fn.IsAbsolute() )
 489     {
 490         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 491     }
 492
 493     m_strName = fn.GetFullPath();
 494
 495     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 496
 497     if ( m_strTemp.empty() )
 498     {
 499         // CreateTempFileName() failed
 500         return false;
 501     }
 502
 503 #ifdef __UNIX__
 504     // the temp file should have the same permissions as the original one
 505     mode_t mode;
 506
 507     wxStructStat st;
 508     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 509     {
 510         mode = st.st_mode;
 511     }
 512     else
 513     {
 514         // file probably didn't exist, just give it the default mode _using_
 515         // user's umask (new files creation should respect umask)
 516         mode_t mask = umask(0777);
 517         mode = 0666 & ~mask;
 518         umask(mask);
 519     }
 520
 521     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 522     {
 523 #ifndef __OS2__
 524         wxLogSysError(_("Failed to set temporary file permissions"));
 525 #endif
 526     }
 527 #endif // Unix
 528
 529     return true;
 530 }
 531
 532 // ----------------------------------------------------------------------------
 533 // destruction
 534 // ----------------------------------------------------------------------------
 535
 536 wxTempFile::~wxTempFile()
 537 {
 538     if ( IsOpened() )
 539         Discard();
 540 }
 541
 542 bool wxTempFile::Commit()
 543 {
 544     m_file.Close();
 545
 546     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 547         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 548         return false;
 549     }
 550
 551     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 552         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 553         return false;
 554     }
 555
 556     return true;
 557 }
 558
 559 void wxTempFile::Discard()
 560 {
 561     m_file.Close();
 562     if ( wxRemove(m_strTemp) != 0 )
 563         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 564 }
 565
 566 #endif // wxUSE_FILE
 567