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 // there is no distinction between text and binary files under Unix, so define
 103 // O_BINARY as 0 if the system headers don't do it already
 104 #if defined(__UNIX__) && !defined(O_BINARY)
 105     #define   O_BINARY    (0)
 106 #endif  //__UNIX__
 107
 108 #ifdef __SALFORDC__
 109     #include <unix.h>
 110 #endif
 111
 112 #ifndef MAX_PATH
 113     #define MAX_PATH 512
 114 #endif
 115
 116 // some broken compilers don't have 3rd argument in open() and creat()
 117 #ifdef __SALFORDC__
 118     #define ACCESS(access)
 119     #define stat    _stat
 120 #else // normal compiler
 121     #define ACCESS(access)  , (access)
 122 #endif // Salford C
 123
 124 // wxWidgets
 125 #ifndef WX_PRECOMP
 126     #include  "wx/string.h"
 127     #include  "wx/intl.h"
 128     #include  "wx/log.h"
 129 #endif // !WX_PRECOMP
 130
 131 #include  "wx/filename.h"
 132 #include  "wx/file.h"
 133 #include  "wx/filefn.h"
 134
 135 #ifdef __WXMSW__
 136     #include "wx/msw/mslu.h"
 137 #endif
 138
 139 #ifdef __WXWINCE__
 140     #include "wx/msw/private.h"
 141 #endif
 142
 143
 144 // ============================================================================
 145 // implementation of wxFile
 146 // ============================================================================
 147
 148 // ----------------------------------------------------------------------------
 149 // static functions
 150 // ----------------------------------------------------------------------------
 151
 152 bool wxFile::Exists(const wxChar *name)
 153 {
 154     return wxFileExists(name);
 155 }
 156
 157 bool wxFile::Access(const wxChar *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 wxChar *szFileName, OpenMode mode)
 189 {
 190     m_fd = fd_invalid;
 191     m_error = false;
 192
 193     Open(szFileName, mode);
 194 }
 195
 196 // create the file, fail if it already exists and bOverwrite
 197 bool wxFile::Create(const wxChar *szFileName, 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 #if defined(__WXMAC__) && !defined(__UNIX__) && !wxUSE_UNICODE
 202     // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
 203     // int fd = open( szFileName , O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 204     int fd = creat( szFileName , accessMode);
 205 #else
 206     int fd = wxOpen( szFileName,
 207                      O_BINARY | O_WRONLY | O_CREAT |
 208                      (bOverwrite ? O_TRUNC : O_EXCL)
 209                      ACCESS(accessMode) );
 210 #endif
 211     if ( fd == -1 )
 212     {
 213         wxLogSysError(_("can't create file '%s'"), szFileName);
 214         return false;
 215     }
 216     else
 217     {
 218         Attach(fd);
 219         return true;
 220     }
 221 }
 222
 223 // open the file
 224 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 225 {
 226     int flags = O_BINARY;
 227
 228     switch ( mode )
 229     {
 230         case read:
 231             flags |= O_RDONLY;
 232             break;
 233
 234         case write_append:
 235             if ( wxFile::Exists(szFileName) )
 236             {
 237                 flags |= O_WRONLY | O_APPEND;
 238                 break;
 239             }
 240             //else: fall through as write_append is the same as write if the
 241             //      file doesn't exist
 242
 243         case write:
 244             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 245             break;
 246
 247         case write_excl:
 248             flags |= O_WRONLY | O_CREAT | O_EXCL;
 249             break;
 250
 251         case read_write:
 252             flags |= O_RDWR;
 253             break;
 254     }
 255
 256 #ifdef __WINDOWS__
 257     // only read/write bits for "all" are supported by this function under
 258     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 259     // accessMode, so clear them as they have at best no effect anyhow
 260     accessMode &= wxS_IRUSR | wxS_IWUSR;
 261 #endif // __WINDOWS__
 262
 263     int fd = wxOpen( szFileName, flags ACCESS(accessMode));
 264
 265     if ( fd == -1 )
 266     {
 267         wxLogSysError(_("can't open file '%s'"), szFileName);
 268         return false;
 269     }
 270     else {
 271         Attach(fd);
 272         return true;
 273     }
 274 }
 275
 276 // close
 277 bool wxFile::Close()
 278 {
 279     if ( IsOpened() ) {
 280         if (wxClose(m_fd) == -1)
 281         {
 282             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 283             m_fd = fd_invalid;
 284             return false;
 285         }
 286         else
 287             m_fd = fd_invalid;
 288     }
 289
 290     return true;
 291 }
 292
 293 // ----------------------------------------------------------------------------
 294 // read/write
 295 // ----------------------------------------------------------------------------
 296
 297 // read
 298 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 299 {
 300     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 301
 302     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 303
 304     if ( iRc == -1 )
 305     {
 306         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 307         return wxInvalidOffset;
 308     }
 309
 310     return iRc;
 311 }
 312
 313 // write
 314 size_t wxFile::Write(const void *pBuf, size_t nCount)
 315 {
 316     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 317
 318     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 319
 320     if ( iRc == -1 )
 321     {
 322         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 323         m_error = true;
 324         iRc = 0;
 325     }
 326
 327     return iRc;
 328 }
 329
 330 // flush
 331 bool wxFile::Flush()
 332 {
 333 #if defined(__VISUALC__) || defined(HAVE_FSYNC)
 334     // fsync() only works on disk files and returns errors for pipes, don't
 335     // call it then
 336     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 337     {
 338         if ( wxFsync(m_fd) == -1 )
 339         {
 340             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 341             return false;
 342         }
 343     }
 344 #endif // fsync
 345
 346     return true;
 347 }
 348
 349 // ----------------------------------------------------------------------------
 350 // seek
 351 // ----------------------------------------------------------------------------
 352
 353 // seek
 354 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 355 {
 356     wxASSERT_MSG( IsOpened(), _T("can't seek on closed file") );
 357     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 358                  wxInvalidOffset,
 359                  _T("invalid absolute file offset") );
 360
 361     int origin;
 362     switch ( mode ) {
 363         default:
 364             wxFAIL_MSG(_("unknown seek origin"));
 365
 366         case wxFromStart:
 367             origin = SEEK_SET;
 368             break;
 369
 370         case wxFromCurrent:
 371             origin = SEEK_CUR;
 372             break;
 373
 374         case wxFromEnd:
 375             origin = SEEK_END;
 376             break;
 377     }
 378
 379     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 380     if ( iRc == wxInvalidOffset )
 381     {
 382         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 383     }
 384
 385     return iRc;
 386 }
 387
 388 // get current file offset
 389 wxFileOffset wxFile::Tell() const
 390 {
 391     wxASSERT( IsOpened() );
 392
 393     wxFileOffset iRc = wxTell(m_fd);
 394     if ( iRc == wxInvalidOffset )
 395     {
 396         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 397     }
 398
 399     return iRc;
 400 }
 401
 402 // get current file length
 403 wxFileOffset wxFile::Length() const
 404 {
 405     wxASSERT( IsOpened() );
 406
 407     wxFileOffset iRc = Tell();
 408     if ( iRc != wxInvalidOffset ) {
 409         // have to use const_cast :-(
 410         wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
 411         if ( iLen != wxInvalidOffset ) {
 412             // restore old position
 413             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 414                 // error
 415                 iLen = wxInvalidOffset;
 416             }
 417         }
 418
 419         iRc = iLen;
 420     }
 421
 422     if ( iRc == wxInvalidOffset )
 423     {
 424         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 425     }
 426
 427     return iRc;
 428 }
 429
 430 // is end of file reached?
 431 bool wxFile::Eof() const
 432 {
 433     wxASSERT( IsOpened() );
 434
 435     wxFileOffset iRc;
 436
 437 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 438     // @@ this doesn't work, of course, on unseekable file descriptors
 439     wxFileOffset ofsCur = Tell(),
 440     ofsMax = Length();
 441     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 442         iRc = wxInvalidOffset;
 443     else
 444         iRc = ofsCur == ofsMax;
 445 #else  // Windows and "native" compiler
 446     iRc = wxEof(m_fd);
 447 #endif // Windows/Unix
 448
 449     if ( iRc == 1)
 450         {}
 451     else if ( iRc == 0 )
 452         return false;
 453     else if ( iRc == wxInvalidOffset )
 454         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 455     else
 456         wxFAIL_MSG(_("invalid eof() return value."));
 457
 458     return true;
 459 }
 460
 461 // ============================================================================
 462 // implementation of wxTempFile
 463 // ============================================================================
 464
 465 // ----------------------------------------------------------------------------
 466 // construction
 467 // ----------------------------------------------------------------------------
 468
 469 wxTempFile::wxTempFile(const wxString& strName)
 470 {
 471     Open(strName);
 472 }
 473
 474 bool wxTempFile::Open(const wxString& strName)
 475 {
 476     // we must have an absolute filename because otherwise CreateTempFileName()
 477     // would create the temp file in $TMP (i.e. the system standard location
 478     // for the temp files) which might be on another volume/drive/mount and
 479     // wxRename()ing it later to m_strName from Commit() would then fail
 480     //
 481     // with the absolute filename, the temp file is created in the same
 482     // directory as this one which ensures that wxRename() may work later
 483     wxFileName fn(strName);
 484     if ( !fn.IsAbsolute() )
 485     {
 486         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 487     }
 488
 489     m_strName = fn.GetFullPath();
 490
 491     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 492
 493     if ( m_strTemp.empty() )
 494     {
 495         // CreateTempFileName() failed
 496         return false;
 497     }
 498
 499 #ifdef __UNIX__
 500     // the temp file should have the same permissions as the original one
 501     mode_t mode;
 502
 503     wxStructStat st;
 504     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 505     {
 506         mode = st.st_mode;
 507     }
 508     else
 509     {
 510         // file probably didn't exist, just give it the default mode _using_
 511         // user's umask (new files creation should respect umask)
 512         mode_t mask = umask(0777);
 513         mode = 0666 & ~mask;
 514         umask(mask);
 515     }
 516
 517     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 518     {
 519 #ifndef __OS2__
 520         wxLogSysError(_("Failed to set temporary file permissions"));
 521 #endif
 522     }
 523 #endif // Unix
 524
 525     return true;
 526 }
 527
 528 // ----------------------------------------------------------------------------
 529 // destruction
 530 // ----------------------------------------------------------------------------
 531
 532 wxTempFile::~wxTempFile()
 533 {
 534     if ( IsOpened() )
 535         Discard();
 536 }
 537
 538 bool wxTempFile::Commit()
 539 {
 540     m_file.Close();
 541
 542     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 543         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 544         return false;
 545     }
 546
 547     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 548         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 549         return false;
 550     }
 551
 552     return true;
 553 }
 554
 555 void wxTempFile::Discard()
 556 {
 557     m_file.Close();
 558     if ( wxRemove(m_strTemp) != 0 )
 559         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 560 }
 561
 562 #endif // wxUSE_FILE
 563