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 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(__WXMSW__) && !defined(__GNUWIN32__) && !defined(__WXMICROWIN__) && !defined(__WXWINCE__)
  28
  29 #ifndef __SALFORDC__
  30     #define   WIN32_LEAN_AND_MEAN
  31     #define   NOSERVICE
  32     #define   NOIME
  33     #define   NOATOM
  34     #define   NOGDI
  35     #define   NOGDICAPMASKS
  36     #define   NOMETAFILE
  37     #define   NOMINMAX
  38     #define   NOMSG
  39     #define   NOOPENFILE
  40     #define   NORASTEROPS
  41     #define   NOSCROLL
  42     #define   NOSOUND
  43     #define   NOSYSMETRICS
  44     #define   NOTEXTMETRIC
  45     #define   NOWH
  46     #define   NOCOMM
  47     #define   NOKANJI
  48     #define   NOCRYPT
  49     #define   NOMCX
  50 #endif
  51
  52 #elif defined(__WXMSW__) && defined(__WXWINCE__)
  53     #include  "wx/msw/missing.h"
  54 #elif (defined(__OS2__))
  55     #include <io.h>
  56 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  57     #include  <unistd.h>
  58     #include  <time.h>
  59     #include  <sys/stat.h>
  60     #ifdef __GNUWIN32__
  61         #include "wx/msw/wrapwin.h"
  62     #endif
  63 #elif defined(__DOS__)
  64     #if defined(__WATCOMC__)
  65        #include <io.h>
  66     #elif defined(__DJGPP__)
  67        #include <io.h>
  68        #include <unistd.h>
  69        #include <stdio.h>
  70     #else
  71         #error  "Please specify the header with file functions declarations."
  72     #endif
  73 #elif (defined(__WXSTUBS__))
  74     // Have to ifdef this for different environments
  75     #include <io.h>
  76 #elif (defined(__WXMAC__))
  77 #if __MSL__ < 0x6000
  78     int access( const char *path, int mode ) { return 0 ; }
  79 #else
  80     int _access( const char *path, int mode ) { return 0 ; }
  81 #endif
  82     char* mktemp( char * path ) { return path ;}
  83     #include <stat.h>
  84     #include <unistd.h>
  85 #else
  86     #error  "Please specify the header with file functions declarations."
  87 #endif  //Win/UNIX
  88
  89 #include  <stdio.h>       // SEEK_xxx constants
  90
  91 // Windows compilers don't have these constants
  92 #ifndef W_OK
  93     enum
  94     {
  95         F_OK = 0,   // test for existence
  96         X_OK = 1,   //          execute permission
  97         W_OK = 2,   //          write
  98         R_OK = 4    //          read
  99     };
 100 #endif // W_OK
 101
 102 #ifdef __SALFORDC__
 103     #include <unix.h>
 104 #endif
 105
 106 // some broken compilers don't have 3rd argument in open() and creat()
 107 #ifdef __SALFORDC__
 108     #define ACCESS(access)
 109     #define stat    _stat
 110 #else // normal compiler
 111     #define ACCESS(access)  , (access)
 112 #endif // Salford C
 113
 114 // wxWidgets
 115 #ifndef WX_PRECOMP
 116     #include  "wx/string.h"
 117     #include  "wx/intl.h"
 118     #include  "wx/log.h"
 119     #include "wx/crt.h"
 120 #endif // !WX_PRECOMP
 121
 122 #include  "wx/filename.h"
 123 #include  "wx/file.h"
 124 #include  "wx/filefn.h"
 125
 126 // there is no distinction between text and binary files under Unix, so define
 127 // O_BINARY as 0 if the system headers don't do it already
 128 #if defined(__UNIX__) && !defined(O_BINARY)
 129     #define   O_BINARY    (0)
 130 #endif  //__UNIX__
 131
 132 #ifdef __WXMSW__
 133     #include "wx/msw/mslu.h"
 134 #endif
 135
 136 #ifdef __WXWINCE__
 137     #include "wx/msw/private.h"
 138 #endif
 139
 140 #ifndef MAX_PATH
 141     #define MAX_PATH 512
 142 #endif
 143
 144 // ============================================================================
 145 // implementation of wxFile
 146 // ============================================================================
 147
 148 // ----------------------------------------------------------------------------
 149 // static functions
 150 // ----------------------------------------------------------------------------
 151
 152 bool wxFile::Exists(const wxString& name)
 153 {
 154     return wxFileExists(name);
 155 }
 156
 157 bool wxFile::Access(const wxString& name, OpenMode mode)
 158 {
 159     int how;
 160
 161     switch ( mode )
 162     {
 163         default:
 164             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 165             // fall through
 166
 167         case read:
 168             how = R_OK;
 169             break;
 170
 171         case write:
 172             how = W_OK;
 173             break;
 174
 175         case read_write:
 176             how = R_OK | W_OK;
 177             break;
 178     }
 179
 180     return wxAccess(name, how) == 0;
 181 }
 182
 183 // ----------------------------------------------------------------------------
 184 // opening/closing
 185 // ----------------------------------------------------------------------------
 186
 187 // ctors
 188 wxFile::wxFile(const wxString& fileName, OpenMode mode)
 189 {
 190     m_fd = fd_invalid;
 191     m_error = false;
 192
 193     Open(fileName, mode);
 194 }
 195
 196 // create the file, fail if it already exists and bOverwrite
 197 bool wxFile::Create(const wxString& fileName, bool bOverwrite, int accessMode)
 198 {
 199     // if bOverwrite we create a new file or truncate the existing one,
 200     // otherwise we only create the new file and fail if it already exists
 201     int fd = wxOpen( fileName,
 202                      O_BINARY | O_WRONLY | O_CREAT |
 203                      (bOverwrite ? O_TRUNC : O_EXCL)
 204                      ACCESS(accessMode) );
 205     if ( fd == -1 )
 206     {
 207         wxLogSysError(_("can't create file '%s'"), fileName);
 208         return false;
 209     }
 210
 211     Attach(fd);
 212     return true;
 213 }
 214
 215 // open the file
 216 bool wxFile::Open(const wxString& fileName, OpenMode mode, int accessMode)
 217 {
 218     int flags = O_BINARY;
 219
 220     switch ( mode )
 221     {
 222         case read:
 223             flags |= O_RDONLY;
 224             break;
 225
 226         case write_append:
 227             if ( wxFile::Exists(fileName) )
 228             {
 229                 flags |= O_WRONLY | O_APPEND;
 230                 break;
 231             }
 232             //else: fall through as write_append is the same as write if the
 233             //      file doesn't exist
 234
 235         case write:
 236             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 237             break;
 238
 239         case write_excl:
 240             flags |= O_WRONLY | O_CREAT | O_EXCL;
 241             break;
 242
 243         case read_write:
 244             flags |= O_RDWR;
 245             break;
 246     }
 247
 248 #ifdef __WINDOWS__
 249     // only read/write bits for "all" are supported by this function under
 250     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 251     // accessMode, so clear them as they have at best no effect anyhow
 252     accessMode &= wxS_IRUSR | wxS_IWUSR;
 253 #endif // __WINDOWS__
 254
 255     int fd = wxOpen( fileName, flags ACCESS(accessMode));
 256
 257     if ( fd == -1 )
 258     {
 259         wxLogSysError(_("can't open file '%s'"), fileName);
 260         return false;
 261     }
 262
 263     Attach(fd);
 264     return true;
 265 }
 266
 267 // close
 268 bool wxFile::Close()
 269 {
 270     if ( IsOpened() ) {
 271         if (wxClose(m_fd) == -1)
 272         {
 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 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 290 {
 291     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 292
 293     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 294
 295     if ( iRc == -1 )
 296     {
 297         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 298         return wxInvalidOffset;
 299     }
 300
 301     return iRc;
 302 }
 303
 304 // write
 305 size_t wxFile::Write(const void *pBuf, size_t nCount)
 306 {
 307     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 308
 309     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 310
 311     if ( iRc == -1 )
 312     {
 313         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 314         m_error = true;
 315         iRc = 0;
 316     }
 317
 318     return iRc;
 319 }
 320
 321 bool wxFile::Write(const wxString& s, const wxMBConv& conv)
 322 {
 323   const wxWX2MBbuf buf = s.mb_str(conv);
 324   if ( !buf )
 325       return false;
 326
 327   const size_t size = strlen(buf); // FIXME: use buf.length() when available
 328   return Write(buf, size) == size;
 329 }
 330
 331 // flush
 332 bool wxFile::Flush()
 333 {
 334 #ifdef HAVE_FSYNC
 335     // fsync() only works on disk files and returns errors for pipes, don't
 336     // call it then
 337     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 338     {
 339         if ( wxFsync(m_fd) == -1 )
 340         {
 341             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 342             return false;
 343         }
 344     }
 345 #endif // HAVE_FSYNC
 346
 347     return true;
 348 }
 349
 350 // ----------------------------------------------------------------------------
 351 // seek
 352 // ----------------------------------------------------------------------------
 353
 354 // seek
 355 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 356 {
 357     wxASSERT_MSG( IsOpened(), _T("can't seek on closed file") );
 358     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 359                  wxInvalidOffset,
 360                  _T("invalid absolute file offset") );
 361
 362     int origin;
 363     switch ( mode ) {
 364         default:
 365             wxFAIL_MSG(_T("unknown seek origin"));
 366
 367         case wxFromStart:
 368             origin = SEEK_SET;
 369             break;
 370
 371         case wxFromCurrent:
 372             origin = SEEK_CUR;
 373             break;
 374
 375         case wxFromEnd:
 376             origin = SEEK_END;
 377             break;
 378     }
 379
 380     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 381     if ( iRc == wxInvalidOffset )
 382     {
 383         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 384     }
 385
 386     return iRc;
 387 }
 388
 389 // get current file offset
 390 wxFileOffset wxFile::Tell() const
 391 {
 392     wxASSERT( IsOpened() );
 393
 394     wxFileOffset iRc = wxTell(m_fd);
 395     if ( iRc == wxInvalidOffset )
 396     {
 397         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 398     }
 399
 400     return iRc;
 401 }
 402
 403 // get current file length
 404 wxFileOffset wxFile::Length() const
 405 {
 406     wxASSERT( IsOpened() );
 407
 408     wxFileOffset iRc = Tell();
 409     if ( iRc != wxInvalidOffset ) {
 410         // have to use const_cast :-(
 411         wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
 412         if ( iLen != wxInvalidOffset ) {
 413             // restore old position
 414             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 415                 // error
 416                 iLen = wxInvalidOffset;
 417             }
 418         }
 419
 420         iRc = iLen;
 421     }
 422
 423     if ( iRc == wxInvalidOffset )
 424     {
 425         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 426     }
 427
 428     return iRc;
 429 }
 430
 431 // is end of file reached?
 432 bool wxFile::Eof() const
 433 {
 434     wxASSERT( IsOpened() );
 435
 436     wxFileOffset iRc;
 437
 438 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 439     // @@ this doesn't work, of course, on unseekable file descriptors
 440     wxFileOffset ofsCur = Tell(),
 441     ofsMax = Length();
 442     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 443         iRc = wxInvalidOffset;
 444     else
 445         iRc = ofsCur == ofsMax;
 446 #else  // Windows and "native" compiler
 447     iRc = wxEof(m_fd);
 448 #endif // Windows/Unix
 449
 450     if ( iRc == 1)
 451         {}
 452     else if ( iRc == 0 )
 453         return false;
 454     else if ( iRc == wxInvalidOffset )
 455         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 456     else
 457         wxFAIL_MSG(_T("invalid eof() return value."));
 458
 459     return true;
 460 }
 461
 462 // ============================================================================
 463 // implementation of wxTempFile
 464 // ============================================================================
 465
 466 // ----------------------------------------------------------------------------
 467 // construction
 468 // ----------------------------------------------------------------------------
 469
 470 wxTempFile::wxTempFile(const wxString& strName)
 471 {
 472     Open(strName);
 473 }
 474
 475 bool wxTempFile::Open(const wxString& strName)
 476 {
 477     // we must have an absolute filename because otherwise CreateTempFileName()
 478     // would create the temp file in $TMP (i.e. the system standard location
 479     // for the temp files) which might be on another volume/drive/mount and
 480     // wxRename()ing it later to m_strName from Commit() would then fail
 481     //
 482     // with the absolute filename, the temp file is created in the same
 483     // directory as this one which ensures that wxRename() may work later
 484     wxFileName fn(strName);
 485     if ( !fn.IsAbsolute() )
 486     {
 487         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 488     }
 489
 490     m_strName = fn.GetFullPath();
 491
 492     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 493
 494     if ( m_strTemp.empty() )
 495     {
 496         // CreateTempFileName() failed
 497         return false;
 498     }
 499
 500 #ifdef __UNIX__
 501     // the temp file should have the same permissions as the original one
 502     mode_t mode;
 503
 504     wxStructStat st;
 505     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 506     {
 507         mode = st.st_mode;
 508     }
 509     else
 510     {
 511         // file probably didn't exist, just give it the default mode _using_
 512         // user's umask (new files creation should respect umask)
 513         mode_t mask = umask(0777);
 514         mode = 0666 & ~mask;
 515         umask(mask);
 516     }
 517
 518     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 519     {
 520 #ifndef __OS2__
 521         wxLogSysError(_("Failed to set temporary file permissions"));
 522 #endif
 523     }
 524 #endif // Unix
 525
 526     return true;
 527 }
 528
 529 // ----------------------------------------------------------------------------
 530 // destruction
 531 // ----------------------------------------------------------------------------
 532
 533 wxTempFile::~wxTempFile()
 534 {
 535     if ( IsOpened() )
 536         Discard();
 537 }
 538
 539 bool wxTempFile::Commit()
 540 {
 541     m_file.Close();
 542
 543     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 544         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 545         return false;
 546     }
 547
 548     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 549         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 550         return false;
 551     }
 552
 553     return true;
 554 }
 555
 556 void wxTempFile::Discard()
 557 {
 558     m_file.Close();
 559     if ( wxRemove(m_strTemp) != 0 )
 560         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 561 }
 562
 563 #endif // wxUSE_FILE
 564