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(__WXSTUBS__))
  64     // Have to ifdef this for different environments
  65     #include <io.h>
  66 #elif (defined(__WXMAC__))
  67     int access( const char *path, int mode ) { return 0 ; }
  68     char* mktemp( char * path ) { return path ;}
  69     #include  <unistd.h>
  70     #include  <unix.h>
  71     #define   W_OK        2
  72     #define   R_OK        4
  73 #else
  74     #error  "Please specify the header with file functions declarations."
  75 #endif  //Win/UNIX
  76
  77 #include  <stdio.h>       // SEEK_xxx constants
  78 #include  <fcntl.h>       // O_RDONLY &c
  79
  80 #ifndef __MWERKS__
  81     #include  <sys/types.h>   // needed for stat
  82     #include  <sys/stat.h>    // stat
  83 #endif
  84
  85 // Microsoft compiler loves underscores, feed them to it
  86 #ifdef  __VISUALC__
  87     // functions
  88     #define   open        _open
  89     #define   close       _close
  90     #define   read        _read
  91     #define   write       _write
  92     #define   lseek       _lseek
  93     #define   fsync       _commit
  94     #define   access      _access
  95     #define   eof         _eof
  96
  97     // types
  98     #define   stat        _stat
  99
 100     // constants
 101
 102     #define   O_RDONLY    _O_RDONLY
 103     #define   O_WRONLY    _O_WRONLY
 104     #define   O_RDWR      _O_RDWR
 105     #define   O_EXCL      _O_EXCL
 106     #define   O_CREAT     _O_CREAT
 107     #define   O_BINARY    _O_BINARY
 108
 109     #define   S_IFDIR     _S_IFDIR
 110     #define   S_IFREG     _S_IFREG
 111 #else
 112     #define   tell(fd)    lseek(fd, 0, SEEK_CUR)
 113 #endif  // VC++
 114
 115 #if defined(__BORLANDC__) || defined(_MSC_VER)
 116     #define   W_OK        2
 117     #define   R_OK        4
 118 #endif
 119
 120 // there is no distinction between text and binary files under Unix
 121 #ifdef    __UNIX__
 122     #define   O_BINARY    (0)
 123 #endif  //__UNIX__
 124
 125 #ifdef __SALFORDC__
 126     #include <unix.h>
 127 #endif
 128
 129 // wxWindows
 130 #include  <wx/string.h>
 131 #include  <wx/intl.h>
 132 #include  <wx/file.h>
 133 #include  <wx/log.h>
 134
 135 #ifndef MAX_PATH
 136     #define MAX_PATH 512
 137 #endif
 138
 139 #ifdef __WXMAC__
 140     char gwxMacFileName[ MAX_PATH ] ;
 141     char gwxMacFileName2[ MAX_PATH ] ;
 142     char gwxMacFileName3[ MAX_PATH ] ;
 143 #endif
 144
 145 // some broken compilers don't have 3rd argument in open() and creat()
 146 #ifdef __SALFORDC__
 147     #define ACCESS(access)
 148     #define stat    _stat
 149 #else // normal compiler
 150     #define ACCESS(access)  , (access)
 151 #endif // Salford C
 152
 153 // ============================================================================
 154 // implementation of wxFile
 155 // ============================================================================
 156
 157 // ----------------------------------------------------------------------------
 158 // static functions
 159 // ----------------------------------------------------------------------------
 160 bool wxFile::Exists(const wxChar *name)
 161 {
 162     struct stat st;
 163 #if wxUSE_UNICODE && wxMBFILES
 164     wxCharBuffer fname = wxConvFile.cWC2MB(name);
 165
 166     return !access(fname, 0) &&
 167            !stat(MBSTRINGCAST fname, &st) &&
 168            (st.st_mode & S_IFREG);
 169 #else
 170     return !access(name, 0) &&
 171            !stat((wxChar*) name, &st) &&
 172            (st.st_mode & S_IFREG);
 173 #endif
 174 }
 175
 176 bool wxFile::Access(const wxChar *name, OpenMode mode)
 177 {
 178     int how = 0;
 179
 180     switch ( mode ) {
 181         case read:
 182             how = R_OK;
 183             break;
 184
 185         case write:
 186             how = W_OK;
 187             break;
 188
 189         default:
 190             wxFAIL_MSG(_T("bad wxFile::Access mode parameter."));
 191     }
 192
 193     return access(wxFNCONV(name), how) == 0;
 194 }
 195
 196 // ----------------------------------------------------------------------------
 197 // opening/closing
 198 // ----------------------------------------------------------------------------
 199
 200 // ctors
 201 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 202 {
 203     m_fd = fd_invalid;
 204     m_error = FALSE;
 205
 206     Open(szFileName, mode);
 207 }
 208
 209 // dtor
 210 wxFile::~wxFile()
 211 {
 212     Close();
 213 }
 214
 215 // create the file, fail if it already exists and bOverwrite
 216 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 217 {
 218     // if bOverwrite we create a new file or truncate the existing one,
 219     // otherwise we only create the new file and fail if it already exists
 220     int fd = open(wxFNCONV(szFileName),
 221                   O_WRONLY | O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL)
 222                   ACCESS(accessMode));
 223
 224     if ( fd == -1 ) {
 225         wxLogSysError(_("can't create file '%s'"), szFileName);
 226         return FALSE;
 227     }
 228     else {
 229         Attach(fd);
 230         return TRUE;
 231     }
 232 }
 233
 234 // open the file
 235 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 236 {
 237     int flags = O_BINARY;
 238
 239     switch ( mode ) {
 240         case read:
 241             flags |= O_RDONLY;
 242             break;
 243
 244         case write:
 245             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 246             break;
 247
 248         case write_append:
 249             flags |= O_WRONLY | O_APPEND;
 250             break;
 251
 252         case read_write:
 253             flags |= O_RDWR;
 254             break;
 255     }
 256
 257     int fd = open(wxFNCONV(szFileName), flags ACCESS(accessMode));
 258
 259     if ( fd == -1 ) {
 260         wxLogSysError(_("can't open file '%s'"), szFileName);
 261         return FALSE;
 262     }
 263     else {
 264         Attach(fd);
 265         return TRUE;
 266     }
 267 }
 268
 269 // close
 270 bool wxFile::Close()
 271 {
 272     if ( IsOpened() ) {
 273         if ( close(m_fd) == -1 ) {
 274             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 275             m_fd = fd_invalid;
 276             return FALSE;
 277         }
 278         else
 279             m_fd = fd_invalid;
 280     }
 281
 282     return TRUE;
 283 }
 284
 285 // ----------------------------------------------------------------------------
 286 // read/write
 287 // ----------------------------------------------------------------------------
 288
 289 // read
 290 off_t wxFile::Read(void *pBuf, off_t nCount)
 291 {
 292     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 293
 294 #ifdef __MWERKS__
 295     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 296 #else
 297     int iRc = ::read(m_fd, pBuf, nCount);
 298 #endif
 299     if ( iRc == -1 ) {
 300         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 301         return wxInvalidOffset;
 302     }
 303     else
 304         return (size_t)iRc;
 305 }
 306
 307 // write
 308 size_t wxFile::Write(const void *pBuf, size_t nCount)
 309 {
 310     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 311
 312 #ifdef __MWERKS__
 313     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 314 #else
 315     int iRc = ::write(m_fd, pBuf, nCount);
 316 #endif
 317     if ( iRc == -1 ) {
 318         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 319         m_error = TRUE;
 320         return 0;
 321     }
 322     else
 323         return iRc;
 324 }
 325
 326 // flush
 327 bool wxFile::Flush()
 328 {
 329     if ( IsOpened() ) {
 330 #if defined(__VISUALC__) || wxHAVE_FSYNC
 331         if ( fsync(m_fd) == -1 )
 332         {
 333             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 334             return FALSE;
 335         }
 336 #else // no fsync
 337         // just do nothing
 338 #endif // fsync
 339     }
 340
 341     return TRUE;
 342 }
 343
 344 // ----------------------------------------------------------------------------
 345 // seek
 346 // ----------------------------------------------------------------------------
 347
 348 // seek
 349 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 350 {
 351     wxASSERT( IsOpened() );
 352
 353     int flag = -1;
 354     switch ( mode ) {
 355         case wxFromStart:
 356             flag = SEEK_SET;
 357             break;
 358
 359         case wxFromCurrent:
 360             flag = SEEK_CUR;
 361             break;
 362
 363         case wxFromEnd:
 364             flag = SEEK_END;
 365             break;
 366
 367         default:
 368             wxFAIL_MSG(_("unknown seek origin"));
 369     }
 370
 371     int iRc = lseek(m_fd, ofs, flag);
 372     if ( iRc == -1 ) {
 373         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 374         return wxInvalidOffset;
 375     }
 376     else
 377         return (off_t)iRc;
 378 }
 379
 380 // get current off_t
 381 off_t wxFile::Tell() const
 382 {
 383     wxASSERT( IsOpened() );
 384
 385     int iRc = tell(m_fd);
 386     if ( iRc == -1 ) {
 387         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 388         return wxInvalidOffset;
 389     }
 390     else
 391         return (off_t)iRc;
 392 }
 393
 394 // get current file length
 395 off_t wxFile::Length() const
 396 {
 397     wxASSERT( IsOpened() );
 398
 399 #ifdef __VISUALC__
 400     int iRc = _filelength(m_fd);
 401 #else // !VC++
 402     int iRc = tell(m_fd);
 403     if ( iRc != -1 ) {
 404         // @ have to use const_cast :-(
 405         int iLen = ((wxFile *)this)->SeekEnd();
 406         if ( iLen != -1 ) {
 407             // restore old position
 408             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 409                 // error
 410                 iLen = -1;
 411             }
 412         }
 413
 414         iRc = iLen;
 415     }
 416 #endif  // VC++
 417
 418     if ( iRc == -1 ) {
 419         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 420         return wxInvalidOffset;
 421     }
 422     else
 423         return (off_t)iRc;
 424 }
 425
 426 // is end of file reached?
 427 bool wxFile::Eof() const
 428 {
 429     wxASSERT( IsOpened() );
 430
 431     int iRc;
 432
 433 #if defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 434     // @@ this doesn't work, of course, on unseekable file descriptors
 435     off_t ofsCur = Tell(),
 436     ofsMax = Length();
 437     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 438         iRc = -1;
 439     else
 440         iRc = ofsCur == ofsMax;
 441 #else  // Windows and "native" compiler
 442     iRc = eof(m_fd);
 443 #endif // Windows/Unix
 444
 445     switch ( iRc ) {
 446         case 1:
 447             break;
 448
 449         case 0:
 450             return FALSE;
 451
 452         case -1:
 453             wxLogSysError(_("can't determine if the end of file is reached on \
 454                 descriptor %d"), m_fd);
 455                 break;
 456
 457         default:
 458             wxFAIL_MSG(_("invalid eof() return value."));
 459     }
 460
 461     return TRUE;
 462 }
 463
 464 // ============================================================================
 465 // implementation of wxTempFile
 466 // ============================================================================
 467
 468 // ----------------------------------------------------------------------------
 469 // construction
 470 // ----------------------------------------------------------------------------
 471 wxTempFile::wxTempFile(const wxString& strName)
 472 {
 473     Open(strName);
 474 }
 475
 476 bool wxTempFile::Open(const wxString& strName)
 477 {
 478     m_strName = strName;
 479
 480     // we want to create the file in the same directory as strName because
 481     // otherwise rename() in Commit() might not work (if the files are on
 482     // different partitions for example). Unfortunately, the only standard
 483     // (POSIX) temp file creation function tmpnam() can't do it.
 484 #if defined(__UNIX__) || defined(__WXSTUBS__)|| defined( __WXMAC__ )
 485     static const wxChar *szMktempSuffix = _T("XXXXXX");
 486     m_strTemp << strName << szMktempSuffix;
 487     mktemp(MBSTRINGCAST m_strTemp.mb_str()); // will do because length doesn't change
 488 #else // Windows
 489     wxString strPath;
 490     wxSplitPath(strName, &strPath, NULL, NULL);
 491     if ( strPath.IsEmpty() )
 492         strPath = _T('.');  // GetTempFileName will fail if we give it empty string
 493 #ifdef __WIN32__
 494     if ( !GetTempFileName(strPath, _T("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 495 #else
 496         // Not sure why MSVC++ 1.5 header defines first param as BYTE - bug?
 497         if ( !GetTempFileName((BYTE) (const wxChar*) strPath, _T("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 498 #endif
 499             wxLogLastError(_T("GetTempFileName"));
 500     m_strTemp.UngetWriteBuf();
 501 #endif  // Windows/Unix
 502
 503     int access = wxS_DEFAULT;
 504 #ifdef __UNIX__
 505     // create the file with the same mode as the original one under Unix
 506     mode_t umaskOld = 0; // just to suppress compiler warning
 507     bool changedUmask;
 508
 509     struct stat st;
 510     if ( stat(strName.fn_str(), &st) == 0 )
 511     {
 512         // this assumes that only lower bits of st_mode contain the access
 513         // rights, but it's true for at least all Unices which have S_IXXXX()
 514         // macros, so should not be less portable than using (not POSIX)
 515         // S_IFREG &c
 516         access = st.st_mode & 0777;
 517
 518         // we want to create the file with exactly the same access rights as
 519         // the original one, so disable the user's umask for the moment
 520         umaskOld = umask(0);
 521         changedUmask = TRUE;
 522     }
 523     else
 524     {
 525         // file probably didn't exist, just create with default mode _using_
 526         // user's umask (new files creation should respet umask)
 527         changedUmask = FALSE;
 528     }
 529 #endif // Unix
 530
 531     bool ok = m_file.Open(m_strTemp, wxFile::write, access);
 532
 533 #ifdef __UNIX__
 534     if ( changedUmask )
 535     {
 536         // restore umask now that the file is created
 537         (void)umask(umaskOld);
 538     }
 539 #endif // Unix
 540
 541     return ok;
 542 }
 543
 544 // ----------------------------------------------------------------------------
 545 // destruction
 546 // ----------------------------------------------------------------------------
 547
 548 wxTempFile::~wxTempFile()
 549 {
 550     if ( IsOpened() )
 551         Discard();
 552 }
 553
 554 bool wxTempFile::Commit()
 555 {
 556     m_file.Close();
 557
 558     if ( wxFile::Exists(m_strName) && remove(m_strName.fn_str()) != 0 ) {
 559         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 560         return FALSE;
 561     }
 562
 563     if ( rename(m_strTemp.fn_str(), m_strName.fn_str()) != 0 ) {
 564         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 565         return FALSE;
 566     }
 567
 568     return TRUE;
 569 }
 570
 571 void wxTempFile::Discard()
 572 {
 573     m_file.Close();
 574     if ( remove(m_strTemp.fn_str()) != 0 )
 575         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 576 }
 577
 578 #endif