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 #ifndef WX_PRECOMP
  29   #include "wx/defs.h"
  30 #endif
  31
  32 #if wxUSE_FILE
  33
  34 // standard
  35 #if defined(__WXMSW__) && !defined(__GNUWIN32__) && !defined(__WXWINE__)
  36   #include  <io.h>
  37
  38 #ifndef __SALFORDC__
  39     #define   WIN32_LEAN_AND_MEAN
  40     #define   NOSERVICE
  41     #define   NOIME
  42     #define   NOATOM
  43     #define   NOGDI
  44     #define   NOGDICAPMASKS
  45     #define   NOMETAFILE
  46     #define   NOMINMAX
  47     #define   NOMSG
  48     #define   NOOPENFILE
  49     #define   NORASTEROPS
  50     #define   NOSCROLL
  51     #define   NOSOUND
  52     #define   NOSYSMETRICS
  53     #define   NOTEXTMETRIC
  54     #define   NOWH
  55     #define   NOCOMM
  56     #define   NOKANJI
  57     #define   NOCRYPT
  58     #define   NOMCX
  59 #endif
  60
  61     #include  <windows.h>     // for GetTempFileName
  62 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  63     #include  <unistd.h>
  64     #ifdef __GNUWIN32__
  65         #include <windows.h>
  66     #endif
  67 #elif (defined(__WXSTUBS__))
  68     // Have to ifdef this for different environments
  69     #include <io.h>
  70 #elif (defined(__WXMAC__))
  71     int access( const char *path, int mode ) { return 0 ; }
  72     char* mktemp( char * path ) { return path ;}
  73     #include  <unistd.h>
  74     #include  <unix.h>
  75     #define   W_OK        2
  76     #define   R_OK        4
  77 #else
  78     #error  "Please specify the header with file functions declarations."
  79 #endif  //Win/UNIX
  80
  81 #include  <stdio.h>       // SEEK_xxx constants
  82 #include  <fcntl.h>       // O_RDONLY &c
  83
  84 #ifndef __MWERKS__
  85     #include  <sys/types.h>   // needed for stat
  86     #include  <sys/stat.h>    // stat
  87 #endif
  88
  89 // Microsoft compiler loves underscores, feed them to it
  90 #ifdef  __VISUALC__
  91     // functions
  92     #define   open        _open
  93     #define   close       _close
  94     #define   read        _read
  95     #define   write       _write
  96     #define   lseek       _lseek
  97     #define   fsync       _commit
  98     #define   access      _access
  99     #define   eof         _eof
 100
 101     // types
 102     #define   stat        _stat
 103
 104     // constants
 105
 106     #define   O_RDONLY    _O_RDONLY
 107     #define   O_WRONLY    _O_WRONLY
 108     #define   O_RDWR      _O_RDWR
 109     #define   O_EXCL      _O_EXCL
 110     #define   O_CREAT     _O_CREAT
 111     #define   O_BINARY    _O_BINARY
 112
 113     #define   S_IFDIR     _S_IFDIR
 114     #define   S_IFREG     _S_IFREG
 115 #else
 116     #define   tell(fd)    lseek(fd, 0, SEEK_CUR)
 117 #endif  // VC++
 118
 119 #if defined(__BORLANDC__) || defined(_MSC_VER)
 120     #define   W_OK        2
 121     #define   R_OK        4
 122 #endif
 123
 124 // there is no distinction between text and binary files under Unix
 125 #ifdef    __UNIX__
 126     #define   O_BINARY    (0)
 127 #endif  //__UNIX__
 128
 129 #ifdef __SALFORDC__
 130     #include <unix.h>
 131 #endif
 132
 133 // wxWindows
 134 #include  <wx/string.h>
 135 #include  <wx/intl.h>
 136 #include  <wx/file.h>
 137 #include  <wx/log.h>
 138
 139 #ifndef MAX_PATH
 140     #define MAX_PATH 512
 141 #endif
 142
 143 #ifdef __WXMAC__
 144     char gwxMacFileName[ MAX_PATH ] ;
 145     char gwxMacFileName2[ MAX_PATH ] ;
 146     char gwxMacFileName3[ MAX_PATH ] ;
 147 #endif
 148
 149 // some broken compilers don't have 3rd argument in open() and creat()
 150 #ifdef __SALFORDC__
 151     #define ACCESS(access)
 152     #define stat    _stat
 153 #else // normal compiler
 154     #define ACCESS(access)  , (access)
 155 #endif // Salford C
 156
 157 // ============================================================================
 158 // implementation of wxFile
 159 // ============================================================================
 160
 161 // ----------------------------------------------------------------------------
 162 // static functions
 163 // ----------------------------------------------------------------------------
 164 bool wxFile::Exists(const wxChar *name)
 165 {
 166     struct stat st;
 167 #if wxUSE_UNICODE && wxMBFILES
 168     wxCharBuffer fname = wxConvFile.cWC2MB(name);
 169
 170     return !access(fname, 0) &&
 171            !stat(MBSTRINGCAST fname, &st) &&
 172            (st.st_mode & S_IFREG);
 173 #else
 174     return !access(name, 0) &&
 175            !stat((wxChar*) name, &st) &&
 176            (st.st_mode & S_IFREG);
 177 #endif
 178 }
 179
 180 bool wxFile::Access(const wxChar *name, OpenMode mode)
 181 {
 182     int how = 0;
 183
 184     switch ( mode ) {
 185         case read:
 186             how = R_OK;
 187             break;
 188
 189         case write:
 190             how = W_OK;
 191             break;
 192
 193         default:
 194             wxFAIL_MSG(_T("bad wxFile::Access mode parameter."));
 195     }
 196
 197     return access(wxFNCONV(name), how) == 0;
 198 }
 199
 200 // ----------------------------------------------------------------------------
 201 // opening/closing
 202 // ----------------------------------------------------------------------------
 203
 204 // ctors
 205 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 206 {
 207     m_fd = fd_invalid;
 208     m_error = FALSE;
 209
 210     Open(szFileName, mode);
 211 }
 212
 213 // dtor
 214 wxFile::~wxFile()
 215 {
 216     Close();
 217 }
 218
 219 // create the file, fail if it already exists and bOverwrite
 220 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 221 {
 222     // if bOverwrite we create a new file or truncate the existing one,
 223     // otherwise we only create the new file and fail if it already exists
 224     int fd = open(wxFNCONV(szFileName),
 225                   O_WRONLY | O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL)
 226                   ACCESS(accessMode));
 227
 228     if ( fd == -1 ) {
 229         wxLogSysError(_("can't create file '%s'"), szFileName);
 230         return FALSE;
 231     }
 232     else {
 233         Attach(fd);
 234         return TRUE;
 235     }
 236 }
 237
 238 // open the file
 239 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 240 {
 241     int flags = O_BINARY;
 242
 243     switch ( mode ) {
 244         case read:
 245             flags |= O_RDONLY;
 246             break;
 247
 248         case write:
 249             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 250             break;
 251
 252         case write_append:
 253             flags |= O_WRONLY | O_APPEND;
 254             break;
 255
 256         case read_write:
 257             flags |= O_RDWR;
 258             break;
 259     }
 260
 261     int fd = open(wxFNCONV(szFileName), flags ACCESS(accessMode));
 262
 263     if ( fd == -1 ) {
 264         wxLogSysError(_("can't open file '%s'"), szFileName);
 265         return FALSE;
 266     }
 267     else {
 268         Attach(fd);
 269         return TRUE;
 270     }
 271 }
 272
 273 // close
 274 bool wxFile::Close()
 275 {
 276     if ( IsOpened() ) {
 277         if ( close(m_fd) == -1 ) {
 278             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 279             m_fd = fd_invalid;
 280             return FALSE;
 281         }
 282         else
 283             m_fd = fd_invalid;
 284     }
 285
 286     return TRUE;
 287 }
 288
 289 // ----------------------------------------------------------------------------
 290 // read/write
 291 // ----------------------------------------------------------------------------
 292
 293 // read
 294 off_t wxFile::Read(void *pBuf, off_t nCount)
 295 {
 296     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 297
 298 #ifdef __MWERKS__
 299     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 300 #else
 301     int iRc = ::read(m_fd, pBuf, nCount);
 302 #endif
 303     if ( iRc == -1 ) {
 304         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 305         return wxInvalidOffset;
 306     }
 307     else
 308         return (size_t)iRc;
 309 }
 310
 311 // write
 312 size_t wxFile::Write(const void *pBuf, size_t nCount)
 313 {
 314     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 315
 316 #ifdef __MWERKS__
 317     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 318 #else
 319     int iRc = ::write(m_fd, pBuf, nCount);
 320 #endif
 321     if ( iRc == -1 ) {
 322         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 323         m_error = TRUE;
 324         return 0;
 325     }
 326     else
 327         return iRc;
 328 }
 329
 330 // flush
 331 bool wxFile::Flush()
 332 {
 333     if ( IsOpened() ) {
 334 #if defined(__VISUALC__) || wxHAVE_FSYNC
 335         if ( fsync(m_fd) == -1 )
 336         {
 337             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 338             return FALSE;
 339         }
 340 #else // no fsync
 341         // just do nothing
 342 #endif // fsync
 343     }
 344
 345     return TRUE;
 346 }
 347
 348 // ----------------------------------------------------------------------------
 349 // seek
 350 // ----------------------------------------------------------------------------
 351
 352 // seek
 353 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 354 {
 355     wxASSERT( IsOpened() );
 356
 357     int flag = -1;
 358     switch ( mode ) {
 359         case wxFromStart:
 360             flag = SEEK_SET;
 361             break;
 362
 363         case wxFromCurrent:
 364             flag = SEEK_CUR;
 365             break;
 366
 367         case wxFromEnd:
 368             flag = SEEK_END;
 369             break;
 370
 371         default:
 372             wxFAIL_MSG(_("unknown seek origin"));
 373     }
 374
 375     int iRc = lseek(m_fd, ofs, flag);
 376     if ( iRc == -1 ) {
 377         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 378         return wxInvalidOffset;
 379     }
 380     else
 381         return (off_t)iRc;
 382 }
 383
 384 // get current off_t
 385 off_t wxFile::Tell() const
 386 {
 387     wxASSERT( IsOpened() );
 388
 389     int iRc = tell(m_fd);
 390     if ( iRc == -1 ) {
 391         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 392         return wxInvalidOffset;
 393     }
 394     else
 395         return (off_t)iRc;
 396 }
 397
 398 // get current file length
 399 off_t wxFile::Length() const
 400 {
 401     wxASSERT( IsOpened() );
 402
 403 #ifdef __VISUALC__
 404     int iRc = _filelength(m_fd);
 405 #else // !VC++
 406     int iRc = tell(m_fd);
 407     if ( iRc != -1 ) {
 408         // @ have to use const_cast :-(
 409         int iLen = ((wxFile *)this)->SeekEnd();
 410         if ( iLen != -1 ) {
 411             // restore old position
 412             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 413                 // error
 414                 iLen = -1;
 415             }
 416         }
 417
 418         iRc = iLen;
 419     }
 420 #endif  // VC++
 421
 422     if ( iRc == -1 ) {
 423         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 424         return wxInvalidOffset;
 425     }
 426     else
 427         return (off_t)iRc;
 428 }
 429
 430 // is end of file reached?
 431 bool wxFile::Eof() const
 432 {
 433     wxASSERT( IsOpened() );
 434
 435     int iRc;
 436
 437 #if defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 438     // @@ this doesn't work, of course, on unseekable file descriptors
 439     off_t ofsCur = Tell(),
 440     ofsMax = Length();
 441     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 442         iRc = -1;
 443     else
 444         iRc = ofsCur == ofsMax;
 445 #else  // Windows and "native" compiler
 446     iRc = eof(m_fd);
 447 #endif // Windows/Unix
 448
 449     switch ( iRc ) {
 450         case 1:
 451             break;
 452
 453         case 0:
 454             return FALSE;
 455
 456         case -1:
 457             wxLogSysError(_("can't determine if the end of file is reached on \
 458                 descriptor %d"), m_fd);
 459                 break;
 460
 461         default:
 462             wxFAIL_MSG(_("invalid eof() return value."));
 463     }
 464
 465     return TRUE;
 466 }
 467
 468 // ============================================================================
 469 // implementation of wxTempFile
 470 // ============================================================================
 471
 472 // ----------------------------------------------------------------------------
 473 // construction
 474 // ----------------------------------------------------------------------------
 475 wxTempFile::wxTempFile(const wxString& strName)
 476 {
 477     Open(strName);
 478 }
 479
 480 bool wxTempFile::Open(const wxString& strName)
 481 {
 482     m_strName = strName;
 483
 484     // we want to create the file in the same directory as strName because
 485     // otherwise rename() in Commit() might not work (if the files are on
 486     // different partitions for example). Unfortunately, the only standard
 487     // (POSIX) temp file creation function tmpnam() can't do it.
 488 #if defined(__UNIX__) || defined(__WXSTUBS__)|| defined( __WXMAC__ )
 489     static const wxChar *szMktempSuffix = _T("XXXXXX");
 490     m_strTemp << strName << szMktempSuffix;
 491     mktemp(MBSTRINGCAST m_strTemp.mb_str()); // will do because length doesn't change
 492 #else // Windows
 493     wxString strPath;
 494     wxSplitPath(strName, &strPath, NULL, NULL);
 495     if ( strPath.IsEmpty() )
 496         strPath = _T('.');  // GetTempFileName will fail if we give it empty string
 497 #ifdef __WIN32__
 498     if ( !GetTempFileName(strPath, _T("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 499 #else
 500         // Not sure why MSVC++ 1.5 header defines first param as BYTE - bug?
 501         if ( !GetTempFileName((BYTE) (const wxChar*) strPath, _T("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 502 #endif
 503             wxLogLastError(_T("GetTempFileName"));
 504     m_strTemp.UngetWriteBuf();
 505 #endif  // Windows/Unix
 506
 507     int access = wxS_DEFAULT;
 508 #ifdef __UNIX__
 509     // create the file with the same mode as the original one under Unix
 510     mode_t umaskOld = 0; // just to suppress compiler warning
 511     bool changedUmask;
 512
 513     struct stat st;
 514     if ( stat(strName.fn_str(), &st) == 0 )
 515     {
 516         // this assumes that only lower bits of st_mode contain the access
 517         // rights, but it's true for at least all Unices which have S_IXXXX()
 518         // macros, so should not be less portable than using (not POSIX)
 519         // S_IFREG &c
 520         access = st.st_mode & 0777;
 521
 522         // we want to create the file with exactly the same access rights as
 523         // the original one, so disable the user's umask for the moment
 524         umaskOld = umask(0);
 525         changedUmask = TRUE;
 526     }
 527     else
 528     {
 529         // file probably didn't exist, just create with default mode _using_
 530         // user's umask (new files creation should respet umask)
 531         changedUmask = FALSE;
 532     }
 533 #endif // Unix
 534
 535     bool ok = m_file.Open(m_strTemp, wxFile::write, access);
 536
 537 #ifdef __UNIX__
 538     if ( changedUmask )
 539     {
 540         // restore umask now that the file is created
 541         (void)umask(umaskOld);
 542     }
 543 #endif // Unix
 544
 545     return ok;
 546 }
 547
 548 // ----------------------------------------------------------------------------
 549 // destruction
 550 // ----------------------------------------------------------------------------
 551
 552 wxTempFile::~wxTempFile()
 553 {
 554     if ( IsOpened() )
 555         Discard();
 556 }
 557
 558 bool wxTempFile::Commit()
 559 {
 560     m_file.Close();
 561
 562     if ( wxFile::Exists(m_strName) && remove(m_strName.fn_str()) != 0 ) {
 563         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 564         return FALSE;
 565     }
 566
 567     if ( rename(m_strTemp.fn_str(), m_strName.fn_str()) != 0 ) {
 568         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 569         return FALSE;
 570     }
 571
 572     return TRUE;
 573 }
 574
 575 void wxTempFile::Discard()
 576 {
 577     m_file.Close();
 578     if ( remove(m_strTemp.fn_str()) != 0 )
 579         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 580 }
 581
 582 #endif