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