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
  24 #ifdef __BORLANDC__
  25   #pragma hdrstop
  26 #endif
  27
  28 #if wxUSE_FILE
  29
  30 // standard
  31 #if defined(__WXMSW__) && !defined(__GNUWIN32__) && !defined(__WXMICROWIN__)
  32   #include  <io.h>
  33
  34 #ifndef __SALFORDC__
  35     #define   WIN32_LEAN_AND_MEAN
  36     #define   NOSERVICE
  37     #define   NOIME
  38     #define   NOATOM
  39     #define   NOGDI
  40     #define   NOGDICAPMASKS
  41     #define   NOMETAFILE
  42     #define   NOMINMAX
  43     #define   NOMSG
  44     #define   NOOPENFILE
  45     #define   NORASTEROPS
  46     #define   NOSCROLL
  47     #define   NOSOUND
  48     #define   NOSYSMETRICS
  49     #define   NOTEXTMETRIC
  50     #define   NOWH
  51     #define   NOCOMM
  52     #define   NOKANJI
  53     #define   NOCRYPT
  54     #define   NOMCX
  55 #endif
  56
  57 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  58     #include  <unistd.h>
  59     #ifdef __GNUWIN32__
  60         #include <windows.h>
  61     #endif
  62 #elif defined(__DOS__)
  63     #if defined(__WATCOMC__)
  64        #include <io.h>
  65     #elif defined(__DJGPP__)
  66        #include <io.h>
  67        #include <unistd.h>
  68        #include <stdio.h>
  69     #else
  70         #error  "Please specify the header with file functions declarations."
  71     #endif
  72 #elif (defined(__WXPM__))
  73     #include <io.h>
  74 #elif (defined(__WXSTUBS__))
  75     // Have to ifdef this for different environments
  76     #include <io.h>
  77 #elif (defined(__WXMAC__))
  78 #if __MSL__ < 0x6000
  79     int access( const char *path, int mode ) { return 0 ; }
  80 #else
  81     int _access( const char *path, int mode ) { return 0 ; }
  82 #endif
  83     char* mktemp( char * path ) { return path ;}
  84     #include <stat.h>
  85     #include  <unistd.h>
  86 #else
  87     #error  "Please specify the header with file functions declarations."
  88 #endif  //Win/UNIX
  89
  90 #include  <stdio.h>       // SEEK_xxx constants
  91 #include  <fcntl.h>       // O_RDONLY &c
  92
  93 #if !defined(__MWERKS__) || defined(__WXMSW__)
  94     #include  <sys/types.h>   // needed for stat
  95     #include  <sys/stat.h>    // stat
  96 #endif
  97
  98 // Windows compilers don't have these constants
  99 #ifndef W_OK
 100     enum
 101     {
 102         F_OK = 0,   // test for existence
 103         X_OK = 1,   //          execute permission
 104         W_OK = 2,   //          write
 105         R_OK = 4    //          read
 106     };
 107 #endif // W_OK
 108
 109 // there is no distinction between text and binary files under Unix, so define
 110 // O_BINARY as 0 if the system headers don't do it already
 111 #if defined(__UNIX__) && !defined(O_BINARY)
 112     #define   O_BINARY    (0)
 113 #endif  //__UNIX__
 114
 115 #ifdef __SALFORDC__
 116     #include <unix.h>
 117 #endif
 118
 119 #ifndef MAX_PATH
 120     #define MAX_PATH 512
 121 #endif
 122
 123 // some broken compilers don't have 3rd argument in open() and creat()
 124 #ifdef __SALFORDC__
 125     #define ACCESS(access)
 126     #define stat    _stat
 127 #else // normal compiler
 128     #define ACCESS(access)  , (access)
 129 #endif // Salford C
 130
 131 // wxWindows
 132 #ifndef WX_PRECOMP
 133     #include  "wx/string.h"
 134     #include  "wx/intl.h"
 135     #include  "wx/log.h"
 136 #endif // !WX_PRECOMP
 137
 138 #include  "wx/filename.h"
 139 #include  "wx/file.h"
 140 #include  "wx/filefn.h"
 141
 142 #ifdef __WXMSW__
 143     #include "wx/msw/mslu.h"
 144 #endif
 145
 146 // ============================================================================
 147 // implementation of wxFile
 148 // ============================================================================
 149
 150 // ----------------------------------------------------------------------------
 151 // static functions
 152 // ----------------------------------------------------------------------------
 153
 154 bool wxFile::Exists(const wxChar *name)
 155 {
 156     return wxFileExists(name);
 157 }
 158
 159 bool wxFile::Access(const wxChar *name, OpenMode mode)
 160 {
 161     int how;
 162
 163     switch ( mode )
 164     {
 165         default:
 166             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 167             // fall through
 168
 169         case read:
 170             how = R_OK;
 171             break;
 172
 173         case write:
 174             how = W_OK;
 175             break;
 176
 177         case read_write:
 178             how = R_OK | W_OK;
 179             break;
 180     }
 181
 182     return wxAccess(name, how) == 0;
 183 }
 184
 185 // ----------------------------------------------------------------------------
 186 // opening/closing
 187 // ----------------------------------------------------------------------------
 188
 189 // ctors
 190 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 191 {
 192     m_fd = fd_invalid;
 193     m_error = FALSE;
 194
 195     Open(szFileName, mode);
 196 }
 197
 198 // create the file, fail if it already exists and bOverwrite
 199 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 200 {
 201     // if bOverwrite we create a new file or truncate the existing one,
 202     // otherwise we only create the new file and fail if it already exists
 203 #if defined(__WXMAC__) && !defined(__UNIX__)
 204     // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
 205     // int fd = open(wxUnix2MacFilename( szFileName ), O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 206     int fd = creat( szFileName , accessMode);
 207 #else
 208     int fd = wxOpen( szFileName,
 209                      O_BINARY | O_WRONLY | O_CREAT |
 210                      (bOverwrite ? O_TRUNC : O_EXCL)
 211                      ACCESS(accessMode) );
 212 #endif
 213     if ( fd == -1 )
 214     {
 215         wxLogSysError(_("can't create file '%s'"), szFileName);
 216         return FALSE;
 217     }
 218     else
 219     {
 220         Attach(fd);
 221         return TRUE;
 222     }
 223 }
 224
 225 // open the file
 226 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 227 {
 228     int flags = O_BINARY;
 229
 230     switch ( mode )
 231     {
 232         case read:
 233             flags |= O_RDONLY;
 234             break;
 235
 236         case write_append:
 237             if ( wxFile::Exists(szFileName) )
 238             {
 239                 flags |= O_WRONLY | O_APPEND;
 240                 break;
 241             }
 242             //else: fall through as write_append is the same as write if the
 243             //      file doesn't exist
 244
 245         case write:
 246             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 247             break;
 248
 249         case write_excl:
 250             flags |= O_WRONLY | O_CREAT | O_EXCL;
 251             break;
 252
 253         case read_write:
 254             flags |= O_RDWR;
 255             break;
 256     }
 257
 258     int fd = wxOpen( szFileName, flags ACCESS(accessMode));
 259     if ( fd == -1 )
 260     {
 261         wxLogSysError(_("can't open file '%s'"), szFileName);
 262         return FALSE;
 263     }
 264     else {
 265         Attach(fd);
 266         return TRUE;
 267     }
 268 }
 269
 270 // close
 271 bool wxFile::Close()
 272 {
 273     if ( IsOpened() ) {
 274         if ( close(m_fd) == -1 ) {
 275             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 276             m_fd = fd_invalid;
 277             return FALSE;
 278         }
 279         else
 280             m_fd = fd_invalid;
 281     }
 282
 283     return TRUE;
 284 }
 285
 286 // ----------------------------------------------------------------------------
 287 // read/write
 288 // ----------------------------------------------------------------------------
 289
 290 // read
 291 off_t wxFile::Read(void *pBuf, off_t nCount)
 292 {
 293     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 294
 295 #ifdef __MWERKS__
 296     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 297 #else
 298     int iRc = ::read(m_fd, pBuf, nCount);
 299 #endif
 300     if ( iRc == -1 ) {
 301         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 302         return wxInvalidOffset;
 303     }
 304     else
 305         return (size_t)iRc;
 306 }
 307
 308 // write
 309 size_t wxFile::Write(const void *pBuf, size_t nCount)
 310 {
 311     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 312
 313 #ifdef __MWERKS__
 314 #if __MSL__ >= 0x6000
 315     int iRc = ::write(m_fd, (void*) pBuf, nCount);
 316 #else
 317     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 318 #endif
 319 #else
 320     int iRc = ::write(m_fd, pBuf, nCount);
 321 #endif
 322     if ( iRc == -1 ) {
 323         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 324         m_error = TRUE;
 325         return 0;
 326     }
 327     else
 328         return iRc;
 329 }
 330
 331 // flush
 332 bool wxFile::Flush()
 333 {
 334     if ( IsOpened() ) {
 335 #if defined(__VISUALC__) || wxHAVE_FSYNC
 336         if ( wxFsync(m_fd) == -1 )
 337         {
 338             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 339             return FALSE;
 340         }
 341 #else // no fsync
 342         // just do nothing
 343 #endif // fsync
 344     }
 345
 346     return TRUE;
 347 }
 348
 349 // ----------------------------------------------------------------------------
 350 // seek
 351 // ----------------------------------------------------------------------------
 352
 353 // seek
 354 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 355 {
 356     wxASSERT( IsOpened() );
 357
 358     int origin;
 359     switch ( mode ) {
 360         default:
 361             wxFAIL_MSG(_("unknown seek origin"));
 362
 363         case wxFromStart:
 364             origin = SEEK_SET;
 365             break;
 366
 367         case wxFromCurrent:
 368             origin = SEEK_CUR;
 369             break;
 370
 371         case wxFromEnd:
 372             origin = SEEK_END;
 373             break;
 374     }
 375
 376     int iRc = lseek(m_fd, ofs, origin);
 377     if ( iRc == -1 ) {
 378         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 379         return wxInvalidOffset;
 380     }
 381     else
 382         return (off_t)iRc;
 383 }
 384
 385 // get current off_t
 386 off_t wxFile::Tell() const
 387 {
 388     wxASSERT( IsOpened() );
 389
 390     int iRc = wxTell(m_fd);
 391     if ( iRc == -1 ) {
 392         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 393         return wxInvalidOffset;
 394     }
 395     else
 396         return (off_t)iRc;
 397 }
 398
 399 // get current file length
 400 off_t wxFile::Length() const
 401 {
 402     wxASSERT( IsOpened() );
 403
 404 #ifdef __VISUALC__
 405     int iRc = _filelength(m_fd);
 406 #else // !VC++
 407     int iRc = wxTell(m_fd);
 408     if ( iRc != -1 ) {
 409         // @ have to use const_cast :-(
 410         int iLen = ((wxFile *)this)->SeekEnd();
 411         if ( iLen != -1 ) {
 412             // restore old position
 413             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 414                 // error
 415                 iLen = -1;
 416             }
 417         }
 418
 419         iRc = iLen;
 420     }
 421 #endif  // VC++
 422
 423     if ( iRc == -1 ) {
 424         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 425         return wxInvalidOffset;
 426     }
 427     else
 428         return (off_t)iRc;
 429 }
 430
 431 // is end of file reached?
 432 bool wxFile::Eof() const
 433 {
 434     wxASSERT( IsOpened() );
 435
 436     int 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     off_t ofsCur = Tell(),
 441     ofsMax = Length();
 442     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 443         iRc = -1;
 444     else
 445         iRc = ofsCur == ofsMax;
 446 #else  // Windows and "native" compiler
 447     iRc = eof(m_fd);
 448 #endif // Windows/Unix
 449
 450     switch ( iRc ) {
 451         case 1:
 452             break;
 453
 454         case 0:
 455             return FALSE;
 456
 457         case -1:
 458             wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 459                 break;
 460
 461         default:
 462             wxFAIL_MSG(_("invalid eof() return value."));
 463     }
 464
 465     return TRUE;
 466 }
 467
 468 // ============================================================================
 469 // implementation of wxTempFile
 470 // ============================================================================
 471
 472 // ----------------------------------------------------------------------------
 473 // construction
 474 // ----------------------------------------------------------------------------
 475
 476 wxTempFile::wxTempFile(const wxString& strName)
 477 {
 478     Open(strName);
 479 }
 480
 481 bool wxTempFile::Open(const wxString& strName)
 482 {
 483     // we must have an absolute filename because otherwise CreateTempFileName()
 484     // would create the temp file in $TMP (i.e. the system standard location
 485     // for the temp files) which might be on another volume/drive/mount and
 486     // wxRename()ing it later to m_strName from Commit() would then fail
 487     //
 488     // with the absolute filename, the temp file is created in the same
 489     // directory as this one which ensures that wxRename() may work later
 490     wxFileName fn(strName);
 491     if ( !fn.IsAbsolute() )
 492     {
 493         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 494     }
 495
 496     m_strName = fn.GetFullPath();
 497
 498     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 499
 500     if ( m_strTemp.empty() )
 501     {
 502         // CreateTempFileName() failed
 503         return FALSE;
 504     }
 505
 506 #ifdef __UNIX__
 507     // the temp file should have the same permissions as the original one
 508     mode_t mode;
 509
 510     wxStructStat st;
 511     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 512     {
 513         mode = st.st_mode;
 514     }
 515     else
 516     {
 517         // file probably didn't exist, just give it the default mode _using_
 518         // user's umask (new files creation should respect umask)
 519         mode_t mask = umask(0777);
 520         mode = 0666 & ~mask;
 521         umask(mask);
 522     }
 523
 524     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 525     {
 526         wxLogSysError(_("Failed to set temporary file permissions"));
 527     }
 528 #endif // Unix
 529
 530     return TRUE;
 531 }
 532
 533 // ----------------------------------------------------------------------------
 534 // destruction
 535 // ----------------------------------------------------------------------------
 536
 537 wxTempFile::~wxTempFile()
 538 {
 539     if ( IsOpened() )
 540         Discard();
 541 }
 542
 543 bool wxTempFile::Commit()
 544 {
 545     m_file.Close();
 546
 547     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 548         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 549         return FALSE;
 550     }
 551
 552     if ( wxRename(m_strTemp, m_strName) != 0 ) {
 553         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 554         return FALSE;
 555     }
 556
 557     return TRUE;
 558 }
 559
 560 void wxTempFile::Discard()
 561 {
 562     m_file.Close();
 563     if ( wxRemove(m_strTemp) != 0 )
 564         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 565 }
 566
 567 #endif // wxUSE_FILE
 568