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