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 // create the file, fail if it already exists and bOverwrite
 210 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 211 {
 212     // if bOverwrite we create a new file or truncate the existing one,
 213     // otherwise we only create the new file and fail if it already exists
 214     int fd = open(wxFNCONV(szFileName),
 215                   O_WRONLY | O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL)
 216                   ACCESS(accessMode));
 217
 218     if ( fd == -1 ) {
 219         wxLogSysError(_("can't create file '%s'"), szFileName);
 220         return FALSE;
 221     }
 222     else {
 223         Attach(fd);
 224         return TRUE;
 225     }
 226 }
 227
 228 // open the file
 229 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 230 {
 231     int flags = O_BINARY;
 232
 233     switch ( mode ) {
 234         case read:
 235             flags |= O_RDONLY;
 236             break;
 237
 238         case write:
 239             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 240             break;
 241
 242         case write_append:
 243             flags |= O_WRONLY | O_APPEND;
 244             break;
 245
 246         case read_write:
 247             flags |= O_RDWR;
 248             break;
 249     }
 250
 251     int fd = open(wxFNCONV(szFileName), flags ACCESS(accessMode));
 252
 253     if ( fd == -1 ) {
 254         wxLogSysError(_("can't open file '%s'"), szFileName);
 255         return FALSE;
 256     }
 257     else {
 258         Attach(fd);
 259         return TRUE;
 260     }
 261 }
 262
 263 // close
 264 bool wxFile::Close()
 265 {
 266     if ( IsOpened() ) {
 267         if ( close(m_fd) == -1 ) {
 268             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 269             m_fd = fd_invalid;
 270             return FALSE;
 271         }
 272         else
 273             m_fd = fd_invalid;
 274     }
 275
 276     return TRUE;
 277 }
 278
 279 // ----------------------------------------------------------------------------
 280 // read/write
 281 // ----------------------------------------------------------------------------
 282
 283 // read
 284 off_t wxFile::Read(void *pBuf, off_t nCount)
 285 {
 286     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 287
 288 #ifdef __MWERKS__
 289     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 290 #else
 291     int iRc = ::read(m_fd, pBuf, nCount);
 292 #endif
 293     if ( iRc == -1 ) {
 294         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 295         return wxInvalidOffset;
 296     }
 297     else
 298         return (size_t)iRc;
 299 }
 300
 301 // write
 302 size_t wxFile::Write(const void *pBuf, size_t nCount)
 303 {
 304     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 305
 306 #ifdef __MWERKS__
 307     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 308 #else
 309     int iRc = ::write(m_fd, pBuf, nCount);
 310 #endif
 311     if ( iRc == -1 ) {
 312         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 313         m_error = TRUE;
 314         return 0;
 315     }
 316     else
 317         return iRc;
 318 }
 319
 320 // flush
 321 bool wxFile::Flush()
 322 {
 323     if ( IsOpened() ) {
 324 #if defined(__VISUALC__) || wxHAVE_FSYNC
 325         if ( fsync(m_fd) == -1 )
 326         {
 327             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 328             return FALSE;
 329         }
 330 #else // no fsync
 331         // just do nothing
 332 #endif // fsync
 333     }
 334
 335     return TRUE;
 336 }
 337
 338 // ----------------------------------------------------------------------------
 339 // seek
 340 // ----------------------------------------------------------------------------
 341
 342 // seek
 343 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 344 {
 345     wxASSERT( IsOpened() );
 346
 347     int origin;
 348     switch ( mode ) {
 349         default:
 350             wxFAIL_MSG(_("unknown seek origin"));
 351
 352         case wxFromStart:
 353             origin = SEEK_SET;
 354             break;
 355
 356         case wxFromCurrent:
 357             origin = SEEK_CUR;
 358             break;
 359
 360         case wxFromEnd:
 361             origin = SEEK_END;
 362             break;
 363     }
 364
 365     int iRc = lseek(m_fd, ofs, origin);
 366     if ( iRc == -1 ) {
 367         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 368         return wxInvalidOffset;
 369     }
 370     else
 371         return (off_t)iRc;
 372 }
 373
 374 // get current off_t
 375 off_t wxFile::Tell() const
 376 {
 377     wxASSERT( IsOpened() );
 378
 379     int iRc = tell(m_fd);
 380     if ( iRc == -1 ) {
 381         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 382         return wxInvalidOffset;
 383     }
 384     else
 385         return (off_t)iRc;
 386 }
 387
 388 // get current file length
 389 off_t wxFile::Length() const
 390 {
 391     wxASSERT( IsOpened() );
 392
 393 #ifdef __VISUALC__
 394     int iRc = _filelength(m_fd);
 395 #else // !VC++
 396     int iRc = tell(m_fd);
 397     if ( iRc != -1 ) {
 398         // @ have to use const_cast :-(
 399         int iLen = ((wxFile *)this)->SeekEnd();
 400         if ( iLen != -1 ) {
 401             // restore old position
 402             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 403                 // error
 404                 iLen = -1;
 405             }
 406         }
 407
 408         iRc = iLen;
 409     }
 410 #endif  // VC++
 411
 412     if ( iRc == -1 ) {
 413         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 414         return wxInvalidOffset;
 415     }
 416     else
 417         return (off_t)iRc;
 418 }
 419
 420 // is end of file reached?
 421 bool wxFile::Eof() const
 422 {
 423     wxASSERT( IsOpened() );
 424
 425     int iRc;
 426
 427 #if defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 428     // @@ this doesn't work, of course, on unseekable file descriptors
 429     off_t ofsCur = Tell(),
 430     ofsMax = Length();
 431     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 432         iRc = -1;
 433     else
 434         iRc = ofsCur == ofsMax;
 435 #else  // Windows and "native" compiler
 436     iRc = eof(m_fd);
 437 #endif // Windows/Unix
 438
 439     switch ( iRc ) {
 440         case 1:
 441             break;
 442
 443         case 0:
 444             return FALSE;
 445
 446         case -1:
 447             wxLogSysError(_("can't determine if the end of file is reached on \
 448                 descriptor %d"), m_fd);
 449                 break;
 450
 451         default:
 452             wxFAIL_MSG(_("invalid eof() return value."));
 453     }
 454
 455     return TRUE;
 456 }
 457
 458 // ============================================================================
 459 // implementation of wxTempFile
 460 // ============================================================================
 461
 462 // ----------------------------------------------------------------------------
 463 // construction
 464 // ----------------------------------------------------------------------------
 465 wxTempFile::wxTempFile(const wxString& strName)
 466 {
 467     Open(strName);
 468 }
 469
 470 bool wxTempFile::Open(const wxString& strName)
 471 {
 472     m_strName = strName;
 473
 474     // we want to create the file in the same directory as strName because
 475     // otherwise rename() in Commit() might not work (if the files are on
 476     // different partitions for example). Unfortunately, the only standard
 477     // (POSIX) temp file creation function tmpnam() can't do it.
 478 #if defined(__UNIX__) || defined(__WXSTUBS__)|| defined( __WXMAC__ )
 479     static const wxChar *szMktempSuffix = _T("XXXXXX");
 480     m_strTemp << strName << szMktempSuffix;
 481     mktemp(MBSTRINGCAST m_strTemp.mb_str()); // will do because length doesn't change
 482 #else // Windows
 483     wxString strPath;
 484     wxSplitPath(strName, &strPath, NULL, NULL);
 485     if ( strPath.IsEmpty() )
 486         strPath = _T('.');  // GetTempFileName will fail if we give it empty string
 487 #ifdef __WIN32__
 488     if ( !GetTempFileName(strPath, _T("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 489 #else
 490         // Not sure why MSVC++ 1.5 header defines first param as BYTE - bug?
 491         if ( !GetTempFileName((BYTE) (const wxChar*) strPath, _T("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 492 #endif
 493             wxLogLastError(_T("GetTempFileName"));
 494     m_strTemp.UngetWriteBuf();
 495 #endif  // Windows/Unix
 496
 497     int access = wxS_DEFAULT;
 498 #ifdef __UNIX__
 499     // create the file with the same mode as the original one under Unix
 500     mode_t umaskOld = 0; // just to suppress compiler warning
 501     bool changedUmask;
 502
 503     struct stat st;
 504     if ( stat(strName.fn_str(), &st) == 0 )
 505     {
 506         // this assumes that only lower bits of st_mode contain the access
 507         // rights, but it's true for at least all Unices which have S_IXXXX()
 508         // macros, so should not be less portable than using (not POSIX)
 509         // S_IFREG &c
 510         access = st.st_mode & 0777;
 511
 512         // we want to create the file with exactly the same access rights as
 513         // the original one, so disable the user's umask for the moment
 514         umaskOld = umask(0);
 515         changedUmask = TRUE;
 516     }
 517     else
 518     {
 519         // file probably didn't exist, just create with default mode _using_
 520         // user's umask (new files creation should respet umask)
 521         changedUmask = FALSE;
 522     }
 523 #endif // Unix
 524
 525     bool ok = m_file.Open(m_strTemp, wxFile::write, access);
 526
 527 #ifdef __UNIX__
 528     if ( changedUmask )
 529     {
 530         // restore umask now that the file is created
 531         (void)umask(umaskOld);
 532     }
 533 #endif // Unix
 534
 535     return ok;
 536 }
 537
 538 // ----------------------------------------------------------------------------
 539 // destruction
 540 // ----------------------------------------------------------------------------
 541
 542 wxTempFile::~wxTempFile()
 543 {
 544     if ( IsOpened() )
 545         Discard();
 546 }
 547
 548 bool wxTempFile::Commit()
 549 {
 550     m_file.Close();
 551
 552     if ( wxFile::Exists(m_strName) && remove(m_strName.fn_str()) != 0 ) {
 553         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 554         return FALSE;
 555     }
 556
 557     if ( rename(m_strTemp.fn_str(), m_strName.fn_str()) != 0 ) {
 558         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 559         return FALSE;
 560     }
 561
 562     return TRUE;
 563 }
 564
 565 void wxTempFile::Discard()
 566 {
 567     m_file.Close();
 568     if ( remove(m_strTemp.fn_str()) != 0 )
 569         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 570 }
 571
 572 #endif
 573