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__)
  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 char *name)
 160 {
 161     struct stat st;
 162
 163     return !access(name, 0) &&
 164            !stat((char*) name, &st) &&
 165            (st.st_mode & S_IFREG);
 166 }
 167
 168 bool wxFile::Access(const char *name, OpenMode mode)
 169 {
 170     int how = 0;
 171
 172     switch ( mode ) {
 173         case read:
 174             how = R_OK;
 175             break;
 176
 177         case write:
 178             how = W_OK;
 179             break;
 180
 181         default:
 182             wxFAIL_MSG("bad wxFile::Access mode parameter.");
 183     }
 184
 185     return access(name, how) == 0;
 186 }
 187
 188 // ----------------------------------------------------------------------------
 189 // opening/closing
 190 // ----------------------------------------------------------------------------
 191
 192 // ctors
 193 wxFile::wxFile(const char *szFileName, OpenMode mode)
 194 {
 195     m_fd = fd_invalid;
 196     m_error = FALSE;
 197
 198     Open(szFileName, mode);
 199 }
 200
 201 // dtor
 202 wxFile::~wxFile()
 203 {
 204     Close();
 205 }
 206
 207 // create the file, fail if it already exists and bOverwrite
 208 bool wxFile::Create(const char *szFileName, bool bOverwrite, int accessMode)
 209 {
 210     // if bOverwrite we create a new file or truncate the existing one,
 211     // otherwise we only create the new file and fail if it already exists
 212     int fd = open(szFileName,
 213                   O_WRONLY | O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL)
 214                   ACCESS(accessMode));
 215
 216     if ( fd == -1 ) {
 217         wxLogSysError(_("can't create file '%s'"), szFileName);
 218         return FALSE;
 219     }
 220     else {
 221         Attach(fd);
 222         return TRUE;
 223     }
 224 }
 225
 226 // open the file
 227 bool wxFile::Open(const char *szFileName, OpenMode mode, int accessMode)
 228 {
 229     int flags = O_BINARY;
 230
 231     switch ( mode ) {
 232         case read:
 233             flags |= O_RDONLY;
 234             break;
 235
 236         case write:
 237             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 238             break;
 239
 240         case write_append:
 241             flags |= O_WRONLY | O_APPEND;
 242             break;
 243
 244         case read_write:
 245             flags |= O_RDWR;
 246             break;
 247     }
 248
 249     int fd = open(szFileName, flags ACCESS(accessMode));
 250
 251     if ( fd == -1 ) {
 252         wxLogSysError(_("can't open file '%s'"), szFileName);
 253         return FALSE;
 254     }
 255     else {
 256         Attach(fd);
 257         return TRUE;
 258     }
 259 }
 260
 261 // close
 262 bool wxFile::Close()
 263 {
 264     if ( IsOpened() ) {
 265         if ( close(m_fd) == -1 ) {
 266             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 267             m_fd = fd_invalid;
 268             return FALSE;
 269         }
 270         else
 271             m_fd = fd_invalid;
 272     }
 273
 274     return TRUE;
 275 }
 276
 277 // ----------------------------------------------------------------------------
 278 // read/write
 279 // ----------------------------------------------------------------------------
 280
 281 // read
 282 off_t wxFile::Read(void *pBuf, off_t nCount)
 283 {
 284     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 285
 286 #ifdef __MWERKS__
 287     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 288 #else
 289     int iRc = ::read(m_fd, pBuf, nCount);
 290 #endif
 291     if ( iRc == -1 ) {
 292         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 293         return wxInvalidOffset;
 294     }
 295     else
 296         return (size_t)iRc;
 297 }
 298
 299 // write
 300 size_t wxFile::Write(const void *pBuf, size_t nCount)
 301 {
 302     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 303
 304 #ifdef __MWERKS__
 305     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 306 #else
 307     int iRc = ::write(m_fd, pBuf, nCount);
 308 #endif
 309     if ( iRc == -1 ) {
 310         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 311         m_error = TRUE;
 312         return 0;
 313     }
 314     else
 315         return iRc;
 316 }
 317
 318 // flush
 319 bool wxFile::Flush()
 320 {
 321     if ( IsOpened() ) {
 322 #if defined(__VISUALC__) || wxHAVE_FSYNC
 323         if ( fsync(m_fd) == -1 )
 324         {
 325             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 326             return FALSE;
 327         }
 328 #else // no fsync
 329         // just do nothing
 330 #endif // fsync
 331     }
 332
 333     return TRUE;
 334 }
 335
 336 // ----------------------------------------------------------------------------
 337 // seek
 338 // ----------------------------------------------------------------------------
 339
 340 // seek
 341 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 342 {
 343     wxASSERT( IsOpened() );
 344
 345     int flag = -1;
 346     switch ( mode ) {
 347         case wxFromStart:
 348             flag = SEEK_SET;
 349             break;
 350
 351         case wxFromCurrent:
 352             flag = SEEK_CUR;
 353             break;
 354
 355         case wxFromEnd:
 356             flag = SEEK_END;
 357             break;
 358
 359         default:
 360             wxFAIL_MSG(_("unknown seek origin"));
 361     }
 362
 363     int iRc = lseek(m_fd, ofs, flag);
 364     if ( iRc == -1 ) {
 365         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 366         return wxInvalidOffset;
 367     }
 368     else
 369         return (off_t)iRc;
 370 }
 371
 372 // get current off_t
 373 off_t wxFile::Tell() const
 374 {
 375     wxASSERT( IsOpened() );
 376
 377     int iRc = tell(m_fd);
 378     if ( iRc == -1 ) {
 379         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 380         return wxInvalidOffset;
 381     }
 382     else
 383         return (off_t)iRc;
 384 }
 385
 386 // get current file length
 387 off_t wxFile::Length() const
 388 {
 389     wxASSERT( IsOpened() );
 390
 391 #ifdef __VISUALC__
 392     int iRc = _filelength(m_fd);
 393 #else // !VC++
 394     int iRc = tell(m_fd);
 395     if ( iRc != -1 ) {
 396         // @ have to use const_cast :-(
 397         int iLen = ((wxFile *)this)->SeekEnd();
 398         if ( iLen != -1 ) {
 399             // restore old position
 400             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 401                 // error
 402                 iLen = -1;
 403             }
 404         }
 405
 406         iRc = iLen;
 407     }
 408 #endif  // VC++
 409
 410     if ( iRc == -1 ) {
 411         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 412         return wxInvalidOffset;
 413     }
 414     else
 415         return (off_t)iRc;
 416 }
 417
 418 // is end of file reached?
 419 bool wxFile::Eof() const
 420 {
 421     wxASSERT( IsOpened() );
 422
 423     int iRc;
 424
 425 #if defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 426     // @@ this doesn't work, of course, on unseekable file descriptors
 427     off_t ofsCur = Tell(),
 428     ofsMax = Length();
 429     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 430         iRc = -1;
 431     else
 432         iRc = ofsCur == ofsMax;
 433 #else  // Windows and "native" compiler
 434     iRc = eof(m_fd);
 435 #endif // Windows/Unix
 436
 437     switch ( iRc ) {
 438         case 1:
 439             break;
 440
 441         case 0:
 442             return FALSE;
 443
 444         case -1:
 445             wxLogSysError(_("can't determine if the end of file is reached on \
 446                 descriptor %d"), m_fd);
 447                 break;
 448
 449         default:
 450             wxFAIL_MSG(_("invalid eof() return value."));
 451     }
 452
 453     return TRUE;
 454 }
 455
 456 // ============================================================================
 457 // implementation of wxTempFile
 458 // ============================================================================
 459
 460 // ----------------------------------------------------------------------------
 461 // construction
 462 // ----------------------------------------------------------------------------
 463 wxTempFile::wxTempFile(const wxString& strName)
 464 {
 465     Open(strName);
 466 }
 467
 468 bool wxTempFile::Open(const wxString& strName)
 469 {
 470     m_strName = strName;
 471
 472     // we want to create the file in the same directory as strName because
 473     // otherwise rename() in Commit() might not work (if the files are on
 474     // different partitions for example). Unfortunately, the only standard
 475     // (POSIX) temp file creation function tmpnam() can't do it.
 476 #if defined(__UNIX__) || defined(__WXSTUBS__)|| defined( __WXMAC__ )
 477     static const char *szMktempSuffix = "XXXXXX";
 478     m_strTemp << strName << szMktempSuffix;
 479     mktemp((char *)m_strTemp.c_str()); // will do because length doesn't change
 480 #else // Windows
 481     wxString strPath;
 482     wxSplitPath(strName, &strPath, NULL, NULL);
 483     if ( strPath.IsEmpty() )
 484         strPath = '.';  // GetTempFileName will fail if we give it empty string
 485 #ifdef __WIN32__
 486     if ( !GetTempFileName(strPath, "wx_",0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 487 #else
 488         // Not sure why MSVC++ 1.5 header defines first param as BYTE - bug?
 489         if ( !GetTempFileName((BYTE) (const char*) strPath, "wx_",0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 490 #endif
 491             wxLogLastError("GetTempFileName");
 492     m_strTemp.UngetWriteBuf();
 493 #endif  // Windows/Unix
 494
 495     int access = wxS_DEFAULT;
 496 #ifdef __UNIX__
 497     // create the file with the same mode as the original one under Unix
 498     struct stat st;
 499     if ( stat(strName, &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     else
 508     {
 509         wxLogLastError("stat");
 510     }
 511
 512     // we want to create the file with exactly the same access rights as the
 513     // original one, so disable the user's umask for the moment
 514     mode_t umaskOld = umask(0);
 515 #endif // Unix
 516
 517     bool ok =  m_file.Open(m_strTemp, wxFile::write, access);
 518
 519 #ifdef __UNIX__
 520     // restore umask now that the file is created
 521     (void)umask(umaskOld);
 522 #endif // Unix
 523
 524     return ok;
 525 }
 526
 527 // ----------------------------------------------------------------------------
 528 // destruction
 529 // ----------------------------------------------------------------------------
 530
 531 wxTempFile::~wxTempFile()
 532 {
 533     if ( IsOpened() )
 534         Discard();
 535 }
 536
 537 bool wxTempFile::Commit()
 538 {
 539     m_file.Close();
 540
 541     if ( wxFile::Exists(m_strName) && remove(m_strName) != 0 ) {
 542         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 543         return FALSE;
 544     }
 545
 546     if ( rename(m_strTemp, m_strName) != 0 ) {
 547         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 548         return FALSE;
 549     }
 550
 551     return TRUE;
 552 }
 553
 554 void wxTempFile::Discard()
 555 {
 556     m_file.Close();
 557     if ( remove(m_strTemp) != 0 )
 558         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 559 }