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 #include "wx/defs.h"
  24
  25 #ifdef __BORLANDC__
  26     #pragma hdrstop
  27 #endif
  28
  29 // standard
  30 #if defined(__WXMSW__) && !defined(__GNUWIN32__) && !defined(__WXWINE__)
  31   #include  <io.h>
  32
  33 #ifndef __SALFORDC__
  34     #define   WIN32_LEAN_AND_MEAN
  35     #define   NOSERVICE
  36     #define   NOIME
  37     #define   NOATOM
  38     #define   NOGDI
  39     #define   NOGDICAPMASKS
  40     #define   NOMETAFILE
  41     #define   NOMINMAX
  42     #define   NOMSG
  43     #define   NOOPENFILE
  44     #define   NORASTEROPS
  45     #define   NOSCROLL
  46     #define   NOSOUND
  47     #define   NOSYSMETRICS
  48     #define   NOTEXTMETRIC
  49     #define   NOWH
  50     #define   NOCOMM
  51     #define   NOKANJI
  52     #define   NOCRYPT
  53     #define   NOMCX
  54 #endif
  55
  56     #include  <windows.h>     // for GetTempFileName
  57 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  58     #include  <unistd.h>
  59     #ifdef __GNUWIN32__
  60         #include <windows.h>
  61     #endif
  62 #elif (defined(__WXSTUBS__))
  63     // Have to ifdef this for different environments
  64     #include <io.h>
  65 #elif (defined(__WXMAC__))
  66     int access( const char *path, int mode ) { return 0 ; }
  67     char* mktemp( char * path ) { return path ;}
  68     #include  <unistd.h>
  69     #include  <unix.h>
  70     #define   W_OK        2
  71     #define   R_OK        4
  72 #else
  73     #error  "Please specify the header with file functions declarations."
  74 #endif  //Win/UNIX
  75
  76 #include  <stdio.h>       // SEEK_xxx constants
  77 #include  <fcntl.h>       // O_RDONLY &c
  78
  79 #ifndef __MWERKS__
  80     #include  <sys/types.h>   // needed for stat
  81     #include  <sys/stat.h>    // stat
  82 #endif
  83
  84 // Microsoft compiler loves underscores, feed them to it
  85 #ifdef  __VISUALC__
  86     // functions
  87     #define   open        _open
  88     #define   close       _close
  89     #define   read        _read
  90     #define   write       _write
  91     #define   lseek       _lseek
  92     #define   fsync       _commit
  93     #define   access      _access
  94     #define   eof         _eof
  95
  96     // types
  97     #define   stat        _stat
  98
  99     // constants
 100
 101     #define   O_RDONLY    _O_RDONLY
 102     #define   O_WRONLY    _O_WRONLY
 103     #define   O_RDWR      _O_RDWR
 104     #define   O_EXCL      _O_EXCL
 105     #define   O_CREAT     _O_CREAT
 106     #define   O_BINARY    _O_BINARY
 107
 108     #define   S_IFDIR     _S_IFDIR
 109     #define   S_IFREG     _S_IFREG
 110 #else
 111     #define   tell(fd)    lseek(fd, 0, SEEK_CUR)
 112 #endif  // VC++
 113
 114 #if defined(__BORLANDC__) || defined(_MSC_VER)
 115     #define   W_OK        2
 116     #define   R_OK        4
 117 #endif
 118
 119 // there is no distinction between text and binary files under Unix
 120 #ifdef    __UNIX__
 121     #define   O_BINARY    (0)
 122 #endif  //__UNIX__
 123
 124 #ifdef __SALFORDC__
 125     #include <unix.h>
 126 #endif
 127
 128 // wxWindows
 129 #include  <wx/string.h>
 130 #include  <wx/intl.h>
 131 #include  <wx/file.h>
 132 #include  <wx/log.h>
 133
 134 #ifndef MAX_PATH
 135     #define MAX_PATH 512
 136 #endif
 137
 138 #ifdef __WXMAC__
 139     char gwxMacFileName[ MAX_PATH ] ;
 140     char gwxMacFileName2[ MAX_PATH ] ;
 141     char gwxMacFileName3[ MAX_PATH ] ;
 142 #endif
 143
 144 // some broken compilers don't have 3rd argument in open() and creat()
 145 #ifdef __SALFORDC__
 146     #define ACCESS(access)
 147     #define stat    _stat
 148 #else // normal compiler
 149     #define ACCESS(access)  , (access)
 150 #endif // Salford C
 151
 152 // ============================================================================
 153 // implementation of wxFile
 154 // ============================================================================
 155
 156 // ----------------------------------------------------------------------------
 157 // static functions
 158 // ----------------------------------------------------------------------------
 159 bool wxFile::Exists(const wxChar *name)
 160 {
 161     struct stat st;
 162 #if wxUSE_UNICODE && wxMBFILES
 163     wxCharBuffer fname = wxConvFile.cWC2MB(name);
 164
 165     return !access(fname, 0) &&
 166            !stat(MBSTRINGCAST fname, &st) &&
 167            (st.st_mode & S_IFREG);
 168 #else
 169     return !access(name, 0) &&
 170            !stat((wxChar*) name, &st) &&
 171            (st.st_mode & S_IFREG);
 172 #endif
 173 }
 174
 175 bool wxFile::Access(const wxChar *name, OpenMode mode)
 176 {
 177     int how = 0;
 178
 179     switch ( mode ) {
 180         case read:
 181             how = R_OK;
 182             break;
 183
 184         case write:
 185             how = W_OK;
 186             break;
 187
 188         default:
 189             wxFAIL_MSG(_T("bad wxFile::Access mode parameter."));
 190     }
 191
 192     return access(wxFNCONV(name), how) == 0;
 193 }
 194
 195 // ----------------------------------------------------------------------------
 196 // opening/closing
 197 // ----------------------------------------------------------------------------
 198
 199 // ctors
 200 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 201 {
 202     m_fd = fd_invalid;
 203     m_error = FALSE;
 204
 205     Open(szFileName, mode);
 206 }
 207
 208 // dtor
 209 wxFile::~wxFile()
 210 {
 211     Close();
 212 }
 213
 214 // create the file, fail if it already exists and bOverwrite
 215 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 216 {
 217     // if bOverwrite we create a new file or truncate the existing one,
 218     // otherwise we only create the new file and fail if it already exists
 219     int fd = open(wxFNCONV(szFileName),
 220                   O_WRONLY | O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL)
 221                   ACCESS(accessMode));
 222
 223     if ( fd == -1 ) {
 224         wxLogSysError(_("can't create file '%s'"), szFileName);
 225         return FALSE;
 226     }
 227     else {
 228         Attach(fd);
 229         return TRUE;
 230     }
 231 }
 232
 233 // open the file
 234 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 235 {
 236     int flags = O_BINARY;
 237
 238     switch ( mode ) {
 239         case read:
 240             flags |= O_RDONLY;
 241             break;
 242
 243         case write:
 244             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 245             break;
 246
 247         case write_append:
 248             flags |= O_WRONLY | O_APPEND;
 249             break;
 250
 251         case read_write:
 252             flags |= O_RDWR;
 253             break;
 254     }
 255
 256     int fd = open(wxFNCONV(szFileName), flags ACCESS(accessMode));
 257
 258     if ( fd == -1 ) {
 259         wxLogSysError(_("can't open file '%s'"), szFileName);
 260         return FALSE;
 261     }
 262     else {
 263         Attach(fd);
 264         return TRUE;
 265     }
 266 }
 267
 268 // close
 269 bool wxFile::Close()
 270 {
 271     if ( IsOpened() ) {
 272         if ( close(m_fd) == -1 ) {
 273             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 274             m_fd = fd_invalid;
 275             return FALSE;
 276         }
 277         else
 278             m_fd = fd_invalid;
 279     }
 280
 281     return TRUE;
 282 }
 283
 284 // ----------------------------------------------------------------------------
 285 // read/write
 286 // ----------------------------------------------------------------------------
 287
 288 // read
 289 off_t wxFile::Read(void *pBuf, off_t nCount)
 290 {
 291     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 292
 293 #ifdef __MWERKS__
 294     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 295 #else
 296     int iRc = ::read(m_fd, pBuf, nCount);
 297 #endif
 298     if ( iRc == -1 ) {
 299         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 300         return wxInvalidOffset;
 301     }
 302     else
 303         return (size_t)iRc;
 304 }
 305
 306 // write
 307 size_t wxFile::Write(const void *pBuf, size_t nCount)
 308 {
 309     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 310
 311 #ifdef __MWERKS__
 312     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 313 #else
 314     int iRc = ::write(m_fd, pBuf, nCount);
 315 #endif
 316     if ( iRc == -1 ) {
 317         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 318         m_error = TRUE;
 319         return 0;
 320     }
 321     else
 322         return iRc;
 323 }
 324
 325 // flush
 326 bool wxFile::Flush()
 327 {
 328     if ( IsOpened() ) {
 329 #if defined(__VISUALC__) || wxHAVE_FSYNC
 330         if ( fsync(m_fd) == -1 )
 331         {
 332             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 333             return FALSE;
 334         }
 335 #else // no fsync
 336         // just do nothing
 337 #endif // fsync
 338     }
 339
 340     return TRUE;
 341 }
 342
 343 // ----------------------------------------------------------------------------
 344 // seek
 345 // ----------------------------------------------------------------------------
 346
 347 // seek
 348 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 349 {
 350     wxASSERT( IsOpened() );
 351
 352     int flag = -1;
 353     switch ( mode ) {
 354         case wxFromStart:
 355             flag = SEEK_SET;
 356             break;
 357
 358         case wxFromCurrent:
 359             flag = SEEK_CUR;
 360             break;
 361
 362         case wxFromEnd:
 363             flag = SEEK_END;
 364             break;
 365
 366         default:
 367             wxFAIL_MSG(_("unknown seek origin"));
 368     }
 369
 370     int iRc = lseek(m_fd, ofs, flag);
 371     if ( iRc == -1 ) {
 372         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 373         return wxInvalidOffset;
 374     }
 375     else
 376         return (off_t)iRc;
 377 }
 378
 379 // get current off_t
 380 off_t wxFile::Tell() const
 381 {
 382     wxASSERT( IsOpened() );
 383
 384     int iRc = tell(m_fd);
 385     if ( iRc == -1 ) {
 386         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 387         return wxInvalidOffset;
 388     }
 389     else
 390         return (off_t)iRc;
 391 }
 392
 393 // get current file length
 394 off_t wxFile::Length() const
 395 {
 396     wxASSERT( IsOpened() );
 397
 398 #ifdef __VISUALC__
 399     int iRc = _filelength(m_fd);
 400 #else // !VC++
 401     int iRc = tell(m_fd);
 402     if ( iRc != -1 ) {
 403         // @ have to use const_cast :-(
 404         int iLen = ((wxFile *)this)->SeekEnd();
 405         if ( iLen != -1 ) {
 406             // restore old position
 407             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 408                 // error
 409                 iLen = -1;
 410             }
 411         }
 412
 413         iRc = iLen;
 414     }
 415 #endif  // VC++
 416
 417     if ( iRc == -1 ) {
 418         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 419         return wxInvalidOffset;
 420     }
 421     else
 422         return (off_t)iRc;
 423 }
 424
 425 // is end of file reached?
 426 bool wxFile::Eof() const
 427 {
 428     wxASSERT( IsOpened() );
 429
 430     int iRc;
 431
 432 #if defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 433     // @@ this doesn't work, of course, on unseekable file descriptors
 434     off_t ofsCur = Tell(),
 435     ofsMax = Length();
 436     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 437         iRc = -1;
 438     else
 439         iRc = ofsCur == ofsMax;
 440 #else  // Windows and "native" compiler
 441     iRc = eof(m_fd);
 442 #endif // Windows/Unix
 443
 444     switch ( iRc ) {
 445         case 1:
 446             break;
 447
 448         case 0:
 449             return FALSE;
 450
 451         case -1:
 452             wxLogSysError(_("can't determine if the end of file is reached on \
 453                 descriptor %d"), m_fd);
 454                 break;
 455
 456         default:
 457             wxFAIL_MSG(_("invalid eof() return value."));
 458     }
 459
 460     return TRUE;
 461 }
 462
 463 // ============================================================================
 464 // implementation of wxTempFile
 465 // ============================================================================
 466
 467 // ----------------------------------------------------------------------------
 468 // construction
 469 // ----------------------------------------------------------------------------
 470 wxTempFile::wxTempFile(const wxString& strName)
 471 {
 472     Open(strName);
 473 }
 474
 475 bool wxTempFile::Open(const wxString& strName)
 476 {
 477     m_strName = strName;
 478
 479     // we want to create the file in the same directory as strName because
 480     // otherwise rename() in Commit() might not work (if the files are on
 481     // different partitions for example). Unfortunately, the only standard
 482     // (POSIX) temp file creation function tmpnam() can't do it.
 483 #if defined(__UNIX__) || defined(__WXSTUBS__)|| defined( __WXMAC__ )
 484     static const wxChar *szMktempSuffix = _T("XXXXXX");
 485     m_strTemp << strName << szMktempSuffix;
 486     mktemp(MBSTRINGCAST m_strTemp.mb_str()); // will do because length doesn't change
 487 #else // Windows
 488     wxString strPath;
 489     wxSplitPath(strName, &strPath, NULL, NULL);
 490     if ( strPath.IsEmpty() )
 491         strPath = _T('.');  // GetTempFileName will fail if we give it empty string
 492 #ifdef __WIN32__
 493     if ( !GetTempFileName(strPath, _T("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) (const wxChar*) strPath, _T("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 497 #endif
 498             wxLogLastError(_T("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     struct stat 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 respet umask)
 526         changedUmask = FALSE;
 527     }
 528 #endif // Unix
 529
 530     bool ok = m_file.Open(m_strTemp, wxFile::write, access);
 531
 532 #ifdef __UNIX__
 533     if ( changedUmask )
 534     {
 535         // restore umask now that the file is created
 536         (void)umask(umaskOld);
 537     }
 538 #endif // Unix
 539
 540     return ok;
 541 }
 542
 543 // ----------------------------------------------------------------------------
 544 // destruction
 545 // ----------------------------------------------------------------------------
 546
 547 wxTempFile::~wxTempFile()
 548 {
 549     if ( IsOpened() )
 550         Discard();
 551 }
 552
 553 bool wxTempFile::Commit()
 554 {
 555     m_file.Close();
 556
 557     if ( wxFile::Exists(m_strName) && remove(m_strName.fn_str()) != 0 ) {
 558         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 559         return FALSE;
 560     }
 561
 562     if ( rename(m_strTemp.fn_str(), m_strName.fn_str()) != 0 ) {
 563         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 564         return FALSE;
 565     }
 566
 567     return TRUE;
 568 }
 569
 570 void wxTempFile::Discard()
 571 {
 572     m_file.Close();
 573     if ( remove(m_strTemp.fn_str()) != 0 )
 574         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 575 }