src/common/file.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/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 licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 // ----------------------------------------------------------------------------
  14 // headers
  15 // ----------------------------------------------------------------------------
  16
  17 // For compilers that support precompilation, includes "wx.h".
  18 #include "wx/wxprec.h"
  19
  20 #ifdef __BORLANDC__
  21   #pragma hdrstop
  22 #endif
  23
  24 #if wxUSE_FILE
  25
  26 // standard
  27 #if defined(__WINDOWS__) && !defined(__GNUWIN32__) && !defined(__WXMICROWIN__) && !defined(__WXWINCE__)
  28
  29 #define   WIN32_LEAN_AND_MEAN
  30 #define   NOSERVICE
  31 #define   NOIME
  32 #define   NOATOM
  33 #define   NOGDI
  34 #define   NOGDICAPMASKS
  35 #define   NOMETAFILE
  36 #define   NOMINMAX
  37 #define   NOMSG
  38 #define   NOOPENFILE
  39 #define   NORASTEROPS
  40 #define   NOSCROLL
  41 #define   NOSOUND
  42 #define   NOSYSMETRICS
  43 #define   NOTEXTMETRIC
  44 #define   NOWH
  45 #define   NOCOMM
  46 #define   NOKANJI
  47 #define   NOCRYPT
  48 #define   NOMCX
  49
  50 #elif defined(__WINDOWS__) && defined(__WXWINCE__)
  51     #include  "wx/msw/missing.h"
  52 #elif (defined(__OS2__))
  53     #include <io.h>
  54 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  55     #include  <unistd.h>
  56     #include  <time.h>
  57     #include  <sys/stat.h>
  58     #ifdef __GNUWIN32__
  59         #include "wx/msw/wrapwin.h"
  60     #endif
  61 #elif defined(__DOS__)
  62     #if defined(__WATCOMC__)
  63        #include <io.h>
  64     #elif defined(__DJGPP__)
  65        #include <io.h>
  66        #include <unistd.h>
  67        #include <stdio.h>
  68     #else
  69         #error  "Please specify the header with file functions declarations."
  70     #endif
  71 #elif (defined(__WXSTUBS__))
  72     // Have to ifdef this for different environments
  73     #include <io.h>
  74 #elif (defined(__WXMAC__))
  75 #if __MSL__ < 0x6000
  76     int access( const char *path, int mode ) { return 0 ; }
  77 #else
  78     int _access( const char *path, int mode ) { return 0 ; }
  79 #endif
  80     char* mktemp( char * path ) { return path ;}
  81     #include <stat.h>
  82     #include <unistd.h>
  83 #else
  84     #error  "Please specify the header with file functions declarations."
  85 #endif  //Win/UNIX
  86
  87 #include  <stdio.h>       // SEEK_xxx constants
  88
  89 #ifndef __WXWINCE__
  90     #include <errno.h>
  91 #endif
  92
  93 // Windows compilers don't have these constants
  94 #ifndef W_OK
  95     enum
  96     {
  97         F_OK = 0,   // test for existence
  98         X_OK = 1,   //          execute permission
  99         W_OK = 2,   //          write
 100         R_OK = 4    //          read
 101     };
 102 #endif // W_OK
 103
 104 // wxWidgets
 105 #ifndef WX_PRECOMP
 106     #include  "wx/string.h"
 107     #include  "wx/intl.h"
 108     #include  "wx/log.h"
 109     #include "wx/crt.h"
 110 #endif // !WX_PRECOMP
 111
 112 #include  "wx/filename.h"
 113 #include  "wx/file.h"
 114 #include  "wx/filefn.h"
 115
 116 // there is no distinction between text and binary files under Unix, so define
 117 // O_BINARY as 0 if the system headers don't do it already
 118 #if defined(__UNIX__) && !defined(O_BINARY)
 119     #define   O_BINARY    (0)
 120 #endif  //__UNIX__
 121
 122 #ifdef __WINDOWS__
 123     #include "wx/msw/mslu.h"
 124 #endif
 125
 126 #ifdef __WXWINCE__
 127     #include "wx/msw/private.h"
 128 #endif
 129
 130 #ifndef MAX_PATH
 131     #define MAX_PATH 512
 132 #endif
 133
 134 // ============================================================================
 135 // implementation of wxFile
 136 // ============================================================================
 137
 138 // ----------------------------------------------------------------------------
 139 // static functions
 140 // ----------------------------------------------------------------------------
 141
 142 bool wxFile::Exists(const wxString& name)
 143 {
 144     return wxFileExists(name);
 145 }
 146
 147 bool wxFile::Access(const wxString& name, OpenMode mode)
 148 {
 149     int how;
 150
 151     switch ( mode )
 152     {
 153         default:
 154             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 155             // fall through
 156
 157         case read:
 158             how = R_OK;
 159             break;
 160
 161         case write:
 162             how = W_OK;
 163             break;
 164
 165         case read_write:
 166             how = R_OK | W_OK;
 167             break;
 168     }
 169
 170     return wxAccess(name, how) == 0;
 171 }
 172
 173 // ----------------------------------------------------------------------------
 174 // opening/closing
 175 // ----------------------------------------------------------------------------
 176
 177 // ctors
 178 wxFile::wxFile(const wxString& fileName, OpenMode mode)
 179 {
 180     m_fd = fd_invalid;
 181     m_lasterror = 0;
 182
 183     Open(fileName, mode);
 184 }
 185
 186 bool wxFile::CheckForError(wxFileOffset rc) const
 187 {
 188     if ( rc != -1 )
 189         return false;
 190
 191     const_cast<wxFile *>(this)->m_lasterror =
 192 #ifndef __WXWINCE__
 193                                                 errno
 194 #else
 195                                                 ::GetLastError()
 196 #endif
 197                                                 ;
 198
 199     return true;
 200 }
 201
 202 // create the file, fail if it already exists and bOverwrite
 203 bool wxFile::Create(const wxString& fileName, bool bOverwrite, int accessMode)
 204 {
 205     // if bOverwrite we create a new file or truncate the existing one,
 206     // otherwise we only create the new file and fail if it already exists
 207     int fildes = wxOpen( fileName,
 208                      O_BINARY | O_WRONLY | O_CREAT |
 209                      (bOverwrite ? O_TRUNC : O_EXCL),
 210                      accessMode );
 211     if ( CheckForError(fildes) )
 212     {
 213         wxLogSysError(_("can't create file '%s'"), fileName);
 214         return false;
 215     }
 216
 217     Attach(fildes);
 218     return true;
 219 }
 220
 221 // open the file
 222 bool wxFile::Open(const wxString& fileName, OpenMode mode, int accessMode)
 223 {
 224     int flags = O_BINARY;
 225
 226     switch ( mode )
 227     {
 228         case read:
 229             flags |= O_RDONLY;
 230             break;
 231
 232         case write_append:
 233             if ( wxFile::Exists(fileName) )
 234             {
 235                 flags |= O_WRONLY | O_APPEND;
 236                 break;
 237             }
 238             //else: fall through as write_append is the same as write if the
 239             //      file doesn't exist
 240
 241         case write:
 242             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 243             break;
 244
 245         case write_excl:
 246             flags |= O_WRONLY | O_CREAT | O_EXCL;
 247             break;
 248
 249         case read_write:
 250             flags |= O_RDWR;
 251             break;
 252     }
 253
 254 #ifdef __WINDOWS__
 255     // only read/write bits for "all" are supported by this function under
 256     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 257     // accessMode, so clear them as they have at best no effect anyhow
 258     accessMode &= wxS_IRUSR | wxS_IWUSR;
 259 #endif // __WINDOWS__
 260
 261     int fildes = wxOpen( fileName, flags, accessMode);
 262
 263     if ( CheckForError(fildes) )
 264     {
 265         wxLogSysError(_("can't open file '%s'"), fileName);
 266         return false;
 267     }
 268
 269     Attach(fildes);
 270     return true;
 271 }
 272
 273 // close
 274 bool wxFile::Close()
 275 {
 276     if ( IsOpened() ) {
 277         if ( CheckForError(wxClose(m_fd)) )
 278         {
 279             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 280             m_fd = fd_invalid;
 281             return false;
 282         }
 283         else
 284             m_fd = fd_invalid;
 285     }
 286
 287     return true;
 288 }
 289
 290 // ----------------------------------------------------------------------------
 291 // read/write
 292 // ----------------------------------------------------------------------------
 293
 294 bool wxFile::ReadAll(wxString *str, const wxMBConv& conv)
 295 {
 296     wxCHECK_MSG( str, false, wxS("Output string must be non-NULL") );
 297
 298     ssize_t length = Length();
 299     wxCHECK_MSG( (wxFileOffset)length == Length(), false, wxT("huge file not supported") );
 300
 301     wxCharBuffer buf(length);
 302     char* p = buf.data();
 303     for ( ;; )
 304     {
 305         static const unsigned READSIZE = 4096;
 306
 307         ssize_t nread = Read(p, length > READSIZE ? READSIZE : length);
 308         if ( nread == wxInvalidOffset )
 309             return false;
 310
 311         p += nread;
 312         if ( length <= nread )
 313             break;
 314
 315         length -= nread;
 316     }
 317
 318     *p = 0;
 319
 320     wxString strTmp(buf, conv);
 321     str->swap(strTmp);
 322
 323     return true;
 324 }
 325
 326 // read
 327 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 328 {
 329     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 330
 331     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 332
 333     if ( CheckForError(iRc) )
 334     {
 335         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 336         return wxInvalidOffset;
 337     }
 338
 339     return iRc;
 340 }
 341
 342 // write
 343 size_t wxFile::Write(const void *pBuf, size_t nCount)
 344 {
 345     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 346
 347     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 348
 349     if ( CheckForError(iRc) )
 350     {
 351         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 352         iRc = 0;
 353     }
 354
 355     return iRc;
 356 }
 357
 358 bool wxFile::Write(const wxString& s, const wxMBConv& conv)
 359 {
 360   const wxWX2MBbuf buf = s.mb_str(conv);
 361   if ( !buf )
 362       return false;
 363
 364 #if wxUSE_UNICODE
 365   const size_t size = buf.length();
 366 #else
 367   const size_t size = s.length();
 368 #endif
 369
 370   return Write(buf, size) == size;
 371 }
 372
 373 // flush
 374 bool wxFile::Flush()
 375 {
 376 #ifdef HAVE_FSYNC
 377     // fsync() only works on disk files and returns errors for pipes, don't
 378     // call it then
 379     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 380     {
 381         if ( CheckForError(wxFsync(m_fd)) )
 382         {
 383             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 384             return false;
 385         }
 386     }
 387 #endif // HAVE_FSYNC
 388
 389     return true;
 390 }
 391
 392 // ----------------------------------------------------------------------------
 393 // seek
 394 // ----------------------------------------------------------------------------
 395
 396 // seek
 397 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 398 {
 399     wxASSERT_MSG( IsOpened(), wxT("can't seek on closed file") );
 400     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 401                  wxInvalidOffset,
 402                  wxT("invalid absolute file offset") );
 403
 404     int origin;
 405     switch ( mode ) {
 406         default:
 407             wxFAIL_MSG(wxT("unknown seek origin"));
 408
 409         case wxFromStart:
 410             origin = SEEK_SET;
 411             break;
 412
 413         case wxFromCurrent:
 414             origin = SEEK_CUR;
 415             break;
 416
 417         case wxFromEnd:
 418             origin = SEEK_END;
 419             break;
 420     }
 421
 422     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 423     if ( CheckForError(iRc) )
 424     {
 425         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 426     }
 427
 428     return iRc;
 429 }
 430
 431 // get current file offset
 432 wxFileOffset wxFile::Tell() const
 433 {
 434     wxASSERT( IsOpened() );
 435
 436     wxFileOffset iRc = wxTell(m_fd);
 437     if ( CheckForError(iRc) )
 438     {
 439         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 440     }
 441
 442     return iRc;
 443 }
 444
 445 // get current file length
 446 wxFileOffset wxFile::Length() const
 447 {
 448     wxASSERT( IsOpened() );
 449
 450     // we use a special method for Linux systems where files in sysfs (i.e.
 451     // those under /sys typically) return length of 4096 bytes even when
 452     // they're much smaller -- this is a problem as it results in errors later
 453     // when we try reading 4KB from them
 454 #ifdef __LINUX__
 455     struct stat st;
 456     if ( fstat(m_fd, &st) == 0 )
 457     {
 458         // returning 0 for the special files indicates to the caller that they
 459         // are not seekable
 460         return st.st_blocks ? st.st_size : 0;
 461     }
 462     //else: failed to stat, try the normal method
 463 #endif // __LINUX__
 464
 465     wxFileOffset iRc = Tell();
 466     if ( iRc != wxInvalidOffset ) {
 467         wxFileOffset iLen = const_cast<wxFile *>(this)->SeekEnd();
 468         if ( iLen != wxInvalidOffset ) {
 469             // restore old position
 470             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 471                 // error
 472                 iLen = wxInvalidOffset;
 473             }
 474         }
 475
 476         iRc = iLen;
 477     }
 478
 479     if ( iRc == wxInvalidOffset )
 480     {
 481         // last error was already set by Tell()
 482         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 483     }
 484
 485     return iRc;
 486 }
 487
 488 // is end of file reached?
 489 bool wxFile::Eof() const
 490 {
 491     wxASSERT( IsOpened() );
 492
 493     wxFileOffset iRc;
 494
 495 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__)
 496     // @@ this doesn't work, of course, on unseekable file descriptors
 497     wxFileOffset ofsCur = Tell(),
 498     ofsMax = Length();
 499     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 500         iRc = wxInvalidOffset;
 501     else
 502         iRc = ofsCur == ofsMax;
 503 #else  // Windows and "native" compiler
 504     iRc = wxEof(m_fd);
 505 #endif // Windows/Unix
 506
 507     if ( iRc == 0 )
 508         return false;
 509
 510     if ( iRc == wxInvalidOffset )
 511     {
 512         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 513     }
 514     else if ( iRc != 1 )
 515     {
 516         wxFAIL_MSG(wxT("invalid eof() return value."));
 517     }
 518
 519     return true;
 520 }
 521
 522 // ============================================================================
 523 // implementation of wxTempFile
 524 // ============================================================================
 525
 526 // ----------------------------------------------------------------------------
 527 // construction
 528 // ----------------------------------------------------------------------------
 529
 530 wxTempFile::wxTempFile(const wxString& strName)
 531 {
 532     Open(strName);
 533 }
 534
 535 bool wxTempFile::Open(const wxString& strName)
 536 {
 537     // we must have an absolute filename because otherwise CreateTempFileName()
 538     // would create the temp file in $TMP (i.e. the system standard location
 539     // for the temp files) which might be on another volume/drive/mount and
 540     // wxRename()ing it later to m_strName from Commit() would then fail
 541     //
 542     // with the absolute filename, the temp file is created in the same
 543     // directory as this one which ensures that wxRename() may work later
 544     wxFileName fn(strName);
 545     if ( !fn.IsAbsolute() )
 546     {
 547         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 548     }
 549
 550     m_strName = fn.GetFullPath();
 551
 552     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 553
 554     if ( m_strTemp.empty() )
 555     {
 556         // CreateTempFileName() failed
 557         return false;
 558     }
 559
 560 #ifdef __UNIX__
 561     // the temp file should have the same permissions as the original one
 562     mode_t mode;
 563
 564     wxStructStat st;
 565     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 566     {
 567         mode = st.st_mode;
 568     }
 569     else
 570     {
 571         // file probably didn't exist, just give it the default mode _using_
 572         // user's umask (new files creation should respect umask)
 573         mode_t mask = umask(0777);
 574         mode = 0666 & ~mask;
 575         umask(mask);
 576     }
 577
 578     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 579     {
 580 #ifndef __OS2__
 581         wxLogSysError(_("Failed to set temporary file permissions"));
 582 #endif
 583     }
 584 #endif // Unix
 585
 586     return true;
 587 }
 588
 589 // ----------------------------------------------------------------------------
 590 // destruction
 591 // ----------------------------------------------------------------------------
 592
 593 wxTempFile::~wxTempFile()
 594 {
 595     if ( IsOpened() )
 596         Discard();
 597 }
 598
 599 bool wxTempFile::Commit()
 600 {
 601     m_file.Close();
 602
 603     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 604         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 605         return false;
 606     }
 607
 608     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 609         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 610         return false;
 611     }
 612
 613     return true;
 614 }
 615
 616 void wxTempFile::Discard()
 617 {
 618     m_file.Close();
 619     if ( wxRemove(m_strTemp) != 0 )
 620     {
 621         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 622     }
 623 }
 624
 625 #endif // wxUSE_FILE
 626