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 license
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 // ----------------------------------------------------------------------------
  14 // headers
  15 // ----------------------------------------------------------------------------
  16
  17 #ifdef __GNUG__
  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(__WXWINE__) && !defined(__WXMICROWIN__)
  32   #include  <io.h>
  33
  34 #ifndef __SALFORDC__
  35     #define   WIN32_LEAN_AND_MEAN
  36     #define   NOSERVICE
  37     #define   NOIME
  38     #define   NOATOM
  39     #define   NOGDI
  40     #define   NOGDICAPMASKS
  41     #define   NOMETAFILE
  42     #define   NOMINMAX
  43     #define   NOMSG
  44     #define   NOOPENFILE
  45     #define   NORASTEROPS
  46     #define   NOSCROLL
  47     #define   NOSOUND
  48     #define   NOSYSMETRICS
  49     #define   NOTEXTMETRIC
  50     #define   NOWH
  51     #define   NOCOMM
  52     #define   NOKANJI
  53     #define   NOCRYPT
  54     #define   NOMCX
  55 #endif
  56
  57     #include  <windows.h>     // for GetTempFileName
  58 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  59     #include  <unistd.h>
  60     #ifdef __GNUWIN32__
  61         #include <windows.h>
  62     #endif
  63 #elif (defined(__WXPM__))
  64     #include <io.h>
  65     #define   W_OK        2
  66     #define   R_OK        4
  67 #elif (defined(__WXSTUBS__))
  68     // Have to ifdef this for different environments
  69     #include <io.h>
  70 #elif (defined(__WXMAC__))
  71 #if __MSL__ < 0x6000
  72     int access( const char *path, int mode ) { return 0 ; }
  73 #else
  74     int _access( const char *path, int mode ) { return 0 ; }
  75 #endif
  76     char* mktemp( char * path ) { return path ;}
  77     #include <stat.h>
  78     #define   W_OK        2
  79     #define   R_OK        4
  80     #include  <unistd.h>
  81 #else
  82     #error  "Please specify the header with file functions declarations."
  83 #endif  //Win/UNIX
  84
  85 #include  <stdio.h>       // SEEK_xxx constants
  86 #include  <fcntl.h>       // O_RDONLY &c
  87
  88 #ifndef __MWERKS__
  89     #include  <sys/types.h>   // needed for stat
  90     #include  <sys/stat.h>    // stat
  91 #elif ( defined(__MWERKS__) && defined(__WXMSW__) )
  92     #include  <sys/types.h>   // needed for stat
  93     #include  <sys/stat.h>    // stat
  94 #endif
  95
  96 #if defined(__BORLANDC__) || defined(_MSC_VER)
  97     #define   W_OK        2
  98     #define   R_OK        4
  99 #endif
 100
 101 // there is no distinction between text and binary files under Unix, so define
 102 // O_BINARY as 0 if the system headers don't do it already
 103 #if defined(__UNIX__) && !defined(O_BINARY)
 104     #define   O_BINARY    (0)
 105 #endif  //__UNIX__
 106
 107 #ifdef __SALFORDC__
 108     #include <unix.h>
 109 #endif
 110
 111 #ifndef MAX_PATH
 112     #define MAX_PATH 512
 113 #endif
 114
 115 // some broken compilers don't have 3rd argument in open() and creat()
 116 #ifdef __SALFORDC__
 117     #define ACCESS(access)
 118     #define stat    _stat
 119 #else // normal compiler
 120     #define ACCESS(access)  , (access)
 121 #endif // Salford C
 122
 123 // wxWindows
 124 #include  "wx/string.h"
 125 #include  "wx/intl.h"
 126 #include  "wx/file.h"
 127 #include  "wx/log.h"
 128
 129 // ============================================================================
 130 // implementation of wxFile
 131 // ============================================================================
 132
 133 // ----------------------------------------------------------------------------
 134 // static functions
 135 // ----------------------------------------------------------------------------
 136 bool wxFile::Exists(const wxChar *name)
 137 {
 138     wxStructStat st;
 139 #if wxUSE_UNICODE && wxMBFILES
 140     wxCharBuffer fname = wxConvFile.cWC2MB(name);
 141
 142     return !wxAccess(fname, 0) &&
 143            !wxStat(wxMBSTRINGCAST fname, &st) &&
 144            (st.st_mode & S_IFREG);
 145
 146 #else
 147     return !wxAccess(name, 0) &&
 148            !wxStat(name, &st) &&
 149            (st.st_mode & S_IFREG);
 150 #endif
 151 }
 152
 153 bool wxFile::Access(const wxChar *name, OpenMode mode)
 154 {
 155     int how = 0;
 156
 157     switch ( mode ) {
 158         case read:
 159             how = R_OK;
 160             break;
 161
 162         case write:
 163             how = W_OK;
 164             break;
 165
 166         default:
 167             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 168     }
 169
 170     return wxAccess(wxFNCONV(name), how) == 0;
 171 }
 172
 173 // ----------------------------------------------------------------------------
 174 // opening/closing
 175 // ----------------------------------------------------------------------------
 176
 177 // ctors
 178 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 179 {
 180     m_fd = fd_invalid;
 181     m_error = FALSE;
 182
 183     Open(szFileName, mode);
 184 }
 185
 186 // create the file, fail if it already exists and bOverwrite
 187 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 188 {
 189     // if bOverwrite we create a new file or truncate the existing one,
 190     // otherwise we only create the new file and fail if it already exists
 191 #if defined(__WXMAC__) && !defined(__UNIX__)
 192   // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
 193   // int fd = open(wxUnix2MacFilename( szFileName ), O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 194   int fd = creat( szFileName , accessMode);
 195 #else
 196     int fd = wxOpen(wxFNCONV(szFileName),
 197                     O_BINARY | O_WRONLY | O_CREAT |
 198                     (bOverwrite ? O_TRUNC : O_EXCL)
 199                     ACCESS(accessMode));
 200 #endif
 201     if ( fd == -1 ) {
 202         wxLogSysError(_("can't create file '%s'"), szFileName);
 203         return FALSE;
 204     }
 205     else {
 206         Attach(fd);
 207         return TRUE;
 208     }
 209 }
 210
 211 // open the file
 212 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 213 {
 214     int flags = O_BINARY;
 215
 216     switch ( mode ) {
 217         case read:
 218             flags |= O_RDONLY;
 219             break;
 220
 221         case write_append:
 222             if ( wxFile::Exists(szFileName) )
 223             {
 224                 flags |= O_WRONLY | O_APPEND;
 225                 break;
 226             }
 227             //else: fall through as write_append is the same as write if the
 228             //      file doesn't exist
 229
 230         case write:
 231             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 232             break;
 233
 234         case write_excl:
 235             flags |= O_WRONLY | O_CREAT | O_EXCL;
 236             break;
 237
 238         case read_write:
 239             flags |= O_RDWR;
 240             break;
 241     }
 242
 243     int fd = wxOpen(wxFNCONV(szFileName), flags ACCESS(accessMode));
 244     if ( fd == -1 ) {
 245         wxLogSysError(_("can't open file '%s'"), szFileName);
 246         return FALSE;
 247     }
 248     else {
 249         Attach(fd);
 250         return TRUE;
 251     }
 252 }
 253
 254 // close
 255 bool wxFile::Close()
 256 {
 257     if ( IsOpened() ) {
 258         if ( close(m_fd) == -1 ) {
 259             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 260             m_fd = fd_invalid;
 261             return FALSE;
 262         }
 263         else
 264             m_fd = fd_invalid;
 265     }
 266
 267     return TRUE;
 268 }
 269
 270 // ----------------------------------------------------------------------------
 271 // read/write
 272 // ----------------------------------------------------------------------------
 273
 274 // read
 275 off_t wxFile::Read(void *pBuf, off_t nCount)
 276 {
 277     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 278
 279 #ifdef __MWERKS__
 280     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 281 #else
 282     int iRc = ::read(m_fd, pBuf, nCount);
 283 #endif
 284     if ( iRc == -1 ) {
 285         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 286         return wxInvalidOffset;
 287     }
 288     else
 289         return (size_t)iRc;
 290 }
 291
 292 // write
 293 size_t wxFile::Write(const void *pBuf, size_t nCount)
 294 {
 295     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 296
 297 #ifdef __MWERKS__
 298 #if __MSL__ >= 0x6000
 299     int iRc = ::write(m_fd, (void*) pBuf, nCount);
 300 #else
 301     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 302 #endif
 303 #else
 304     int iRc = ::write(m_fd, pBuf, nCount);
 305 #endif
 306     if ( iRc == -1 ) {
 307         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 308         m_error = TRUE;
 309         return 0;
 310     }
 311     else
 312         return iRc;
 313 }
 314
 315 // flush
 316 bool wxFile::Flush()
 317 {
 318     if ( IsOpened() ) {
 319 #if defined(__VISUALC__) || wxHAVE_FSYNC
 320         if ( wxFsync(m_fd) == -1 )
 321         {
 322             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 323             return FALSE;
 324         }
 325 #else // no fsync
 326         // just do nothing
 327 #endif // fsync
 328     }
 329
 330     return TRUE;
 331 }
 332
 333 // ----------------------------------------------------------------------------
 334 // seek
 335 // ----------------------------------------------------------------------------
 336
 337 // seek
 338 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 339 {
 340     wxASSERT( IsOpened() );
 341
 342     int origin;
 343     switch ( mode ) {
 344         default:
 345             wxFAIL_MSG(_("unknown seek origin"));
 346
 347         case wxFromStart:
 348             origin = SEEK_SET;
 349             break;
 350
 351         case wxFromCurrent:
 352             origin = SEEK_CUR;
 353             break;
 354
 355         case wxFromEnd:
 356             origin = SEEK_END;
 357             break;
 358     }
 359
 360     int iRc = lseek(m_fd, ofs, origin);
 361     if ( iRc == -1 ) {
 362         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 363         return wxInvalidOffset;
 364     }
 365     else
 366         return (off_t)iRc;
 367 }
 368
 369 // get current off_t
 370 off_t wxFile::Tell() const
 371 {
 372     wxASSERT( IsOpened() );
 373
 374     int iRc = wxTell(m_fd);
 375     if ( iRc == -1 ) {
 376         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 377         return wxInvalidOffset;
 378     }
 379     else
 380         return (off_t)iRc;
 381 }
 382
 383 // get current file length
 384 off_t wxFile::Length() const
 385 {
 386     wxASSERT( IsOpened() );
 387
 388 #ifdef __VISUALC__
 389     int iRc = _filelength(m_fd);
 390 #else // !VC++
 391     int iRc = wxTell(m_fd);
 392     if ( iRc != -1 ) {
 393         // @ have to use const_cast :-(
 394         int iLen = ((wxFile *)this)->SeekEnd();
 395         if ( iLen != -1 ) {
 396             // restore old position
 397             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 398                 // error
 399                 iLen = -1;
 400             }
 401         }
 402
 403         iRc = iLen;
 404     }
 405 #endif  // VC++
 406
 407     if ( iRc == -1 ) {
 408         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 409         return wxInvalidOffset;
 410     }
 411     else
 412         return (off_t)iRc;
 413 }
 414
 415 // is end of file reached?
 416 bool wxFile::Eof() const
 417 {
 418     wxASSERT( IsOpened() );
 419
 420     int iRc;
 421
 422 #if defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 423     // @@ this doesn't work, of course, on unseekable file descriptors
 424     off_t ofsCur = Tell(),
 425     ofsMax = Length();
 426     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 427         iRc = -1;
 428     else
 429         iRc = ofsCur == ofsMax;
 430 #else  // Windows and "native" compiler
 431     iRc = eof(m_fd);
 432 #endif // Windows/Unix
 433
 434     switch ( iRc ) {
 435         case 1:
 436             break;
 437
 438         case 0:
 439             return FALSE;
 440
 441         case -1:
 442             wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 443                 break;
 444
 445         default:
 446             wxFAIL_MSG(_("invalid eof() return value."));
 447     }
 448
 449     return TRUE;
 450 }
 451
 452 // ============================================================================
 453 // implementation of wxTempFile
 454 // ============================================================================
 455
 456 // ----------------------------------------------------------------------------
 457 // construction
 458 // ----------------------------------------------------------------------------
 459 wxTempFile::wxTempFile(const wxString& strName)
 460 {
 461     Open(strName);
 462 }
 463
 464 bool wxTempFile::Open(const wxString& strName)
 465 {
 466     m_strName = strName;
 467
 468     // we want to create the file in the same directory as strName because
 469     // otherwise rename() in Commit() might not work (if the files are on
 470     // different partitions for example). Unfortunately, the only standard
 471     // (POSIX) temp file creation function tmpnam() can't do it.
 472 #if defined(__UNIX__) || defined(__WXSTUBS__)|| defined( __WXMAC__ )
 473     static const wxChar *szMktempSuffix = wxT("XXXXXX");
 474     m_strTemp << strName << szMktempSuffix;
 475     // can use the cast because length doesn't change
 476     mktemp(wxMBSTRINGCAST m_strTemp.mb_str());
 477 #elif  defined(__WXPM__)
 478     // for now just create a file
 479     // future enhancements can be to set some extended attributes for file systems
 480     // OS/2 supports that have them (HPFS, FAT32) and security (HPFS386)
 481     static const wxChar *szMktempSuffix = wxT("XXX");
 482     m_strTemp << strName << szMktempSuffix;
 483     // Temporarily remove - MN
 484     #ifndef __WATCOMC__
 485     ::DosCreateDir(m_strTemp.GetWriteBuf(MAX_PATH), NULL);
 486     #endif
 487 #else // Windows
 488     wxString strPath;
 489     wxSplitPath(strName, &strPath, NULL, NULL);
 490     if ( strPath.IsEmpty() )
 491         strPath = wxT('.');  // GetTempFileName will fail if we give it empty string
 492 #ifdef __WIN32__
 493     if ( !GetTempFileName(strPath, wxT("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 494 #else
 495         // Not sure why MSVC++ 1.5 header defines first param as BYTE - bug?
 496         if ( !GetTempFileName((BYTE) (DWORD)(const wxChar*) strPath, wxT("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 497 #endif
 498             wxLogLastError(wxT("GetTempFileName"));
 499     m_strTemp.UngetWriteBuf();
 500 #endif  // Windows/Unix
 501
 502     int access = wxS_DEFAULT;
 503 #ifdef __UNIX__
 504     // create the file with the same mode as the original one under Unix
 505     mode_t umaskOld = 0; // just to suppress compiler warning
 506     bool changedUmask;
 507
 508     wxStructStat st;
 509     if ( stat(strName.fn_str(), &st) == 0 )
 510     {
 511         // this assumes that only lower bits of st_mode contain the access
 512         // rights, but it's true for at least all Unices which have S_IXXXX()
 513         // macros, so should not be less portable than using (not POSIX)
 514         // S_IFREG &c
 515         access = st.st_mode & 0777;
 516
 517         // we want to create the file with exactly the same access rights as
 518         // the original one, so disable the user's umask for the moment
 519         umaskOld = umask(0);
 520         changedUmask = TRUE;
 521     }
 522     else
 523     {
 524         // file probably didn't exist, just create with default mode _using_
 525         // user's umask (new files creation should respect umask)
 526         changedUmask = FALSE;
 527     }
 528 #endif // Unix
 529
 530     // Open this file securely, since it surely should not exist unless
 531     // nefarious activities (or other random bad things) are at play.
 532
 533     bool ok = m_file.Open(m_strTemp, wxFile::write_excl, access);
 534
 535     // FIXME: If !ok here should we loop and try again with another file
 536     //        name?  That is the standard recourse if open(O_EXCL) fails,
 537     //        though of course it should be protected against possible
 538     //        infinite looping too.
 539
 540 #ifdef __UNIX__
 541     if ( changedUmask )
 542     {
 543         // restore umask now that the file is created
 544         (void)umask(umaskOld);
 545     }
 546 #endif // Unix
 547
 548     return ok;
 549 }
 550
 551 // ----------------------------------------------------------------------------
 552 // destruction
 553 // ----------------------------------------------------------------------------
 554
 555 wxTempFile::~wxTempFile()
 556 {
 557     if ( IsOpened() )
 558         Discard();
 559 }
 560
 561 bool wxTempFile::Commit()
 562 {
 563     m_file.Close();
 564
 565     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 566         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 567         return FALSE;
 568     }
 569
 570     if ( wxRename(m_strTemp, m_strName) != 0 ) {
 571         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 572         return FALSE;
 573     }
 574
 575     return TRUE;
 576 }
 577
 578 void wxTempFile::Discard()
 579 {
 580     m_file.Close();
 581     if ( wxRemove(m_strTemp) != 0 )
 582         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 583 }
 584
 585 #endif
 586