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 #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     #include  <sys/stat.h>
  60     #ifdef __GNUWIN32__
  61         #include <windows.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(__WXPM__))
  74     #include <io.h>
  75 #elif (defined(__WXSTUBS__))
  76     // Have to ifdef this for different environments
  77     #include <io.h>
  78 #elif (defined(__WXMAC__))
  79 #if __MSL__ < 0x6000
  80     int access( const char *path, int mode ) { return 0 ; }
  81 #else
  82     int _access( const char *path, int mode ) { return 0 ; }
  83 #endif
  84     char* mktemp( char * path ) { return path ;}
  85     #include <stat.h>
  86     #include  <unistd.h>
  87 #else
  88     #error  "Please specify the header with file functions declarations."
  89 #endif  //Win/UNIX
  90
  91 #include  <stdio.h>       // SEEK_xxx constants
  92 #include  <fcntl.h>       // O_RDONLY &c
  93
  94 #if !defined(__MWERKS__) || defined(__WXMSW__)
  95     #include  <sys/types.h>   // needed for stat
  96     #include  <sys/stat.h>    // stat
  97 #endif
  98
  99 // Windows compilers don't have these constants
 100 #ifndef W_OK
 101     enum
 102     {
 103         F_OK = 0,   // test for existence
 104         X_OK = 1,   //          execute permission
 105         W_OK = 2,   //          write
 106         R_OK = 4    //          read
 107     };
 108 #endif // W_OK
 109
 110 // there is no distinction between text and binary files under Unix, so define
 111 // O_BINARY as 0 if the system headers don't do it already
 112 #if defined(__UNIX__) && !defined(O_BINARY)
 113     #define   O_BINARY    (0)
 114 #endif  //__UNIX__
 115
 116 #ifdef __SALFORDC__
 117     #include <unix.h>
 118 #endif
 119
 120 #ifndef MAX_PATH
 121     #define MAX_PATH 512
 122 #endif
 123
 124 // some broken compilers don't have 3rd argument in open() and creat()
 125 #ifdef __SALFORDC__
 126     #define ACCESS(access)
 127     #define stat    _stat
 128 #else // normal compiler
 129     #define ACCESS(access)  , (access)
 130 #endif // Salford C
 131
 132 // wxWindows
 133 #ifndef WX_PRECOMP
 134     #include  "wx/string.h"
 135     #include  "wx/intl.h"
 136     #include  "wx/log.h"
 137 #endif // !WX_PRECOMP
 138
 139 #include  "wx/filename.h"
 140 #include  "wx/file.h"
 141 #include  "wx/filefn.h"
 142
 143 #ifdef __WXMSW__
 144     #include "wx/msw/mslu.h"
 145 #endif
 146
 147 // ============================================================================
 148 // implementation of wxFile
 149 // ============================================================================
 150
 151 // ----------------------------------------------------------------------------
 152 // static functions
 153 // ----------------------------------------------------------------------------
 154
 155 bool wxFile::Exists(const wxChar *name)
 156 {
 157     return wxFileExists(name);
 158 }
 159
 160 bool wxFile::Access(const wxChar *name, OpenMode mode)
 161 {
 162     int how;
 163
 164     switch ( mode )
 165     {
 166         default:
 167             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 168             // fall through
 169
 170         case read:
 171             how = R_OK;
 172             break;
 173
 174         case write:
 175             how = W_OK;
 176             break;
 177
 178         case read_write:
 179             how = R_OK | W_OK;
 180             break;
 181     }
 182
 183     return wxAccess(name, how) == 0;
 184 }
 185
 186 // ----------------------------------------------------------------------------
 187 // opening/closing
 188 // ----------------------------------------------------------------------------
 189
 190 // ctors
 191 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 192 {
 193     m_fd = fd_invalid;
 194     m_error = FALSE;
 195
 196     Open(szFileName, mode);
 197 }
 198
 199 // create the file, fail if it already exists and bOverwrite
 200 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 201 {
 202     // if bOverwrite we create a new file or truncate the existing one,
 203     // otherwise we only create the new file and fail if it already exists
 204 #if defined(__WXMAC__) && !defined(__UNIX__)
 205     // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
 206     // int fd = open(wxUnix2MacFilename( szFileName ), O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 207     int fd = creat( szFileName , accessMode);
 208 #else
 209     int fd = wxOpen( szFileName,
 210                      O_BINARY | O_WRONLY | O_CREAT |
 211                      (bOverwrite ? O_TRUNC : O_EXCL)
 212                      ACCESS(accessMode) );
 213 #endif
 214     if ( fd == -1 )
 215     {
 216         wxLogSysError(_("can't create file '%s'"), szFileName);
 217         return FALSE;
 218     }
 219     else
 220     {
 221         Attach(fd);
 222         return TRUE;
 223     }
 224 }
 225
 226 // open the file
 227 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 228 {
 229     int flags = O_BINARY;
 230
 231     switch ( mode )
 232     {
 233         case read:
 234             flags |= O_RDONLY;
 235             break;
 236
 237         case write_append:
 238             if ( wxFile::Exists(szFileName) )
 239             {
 240                 flags |= O_WRONLY | O_APPEND;
 241                 break;
 242             }
 243             //else: fall through as write_append is the same as write if the
 244             //      file doesn't exist
 245
 246         case write:
 247             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 248             break;
 249
 250         case write_excl:
 251             flags |= O_WRONLY | O_CREAT | O_EXCL;
 252             break;
 253
 254         case read_write:
 255             flags |= O_RDWR;
 256             break;
 257     }
 258
 259     int fd = wxOpen( szFileName, flags ACCESS(accessMode));
 260     if ( fd == -1 )
 261     {
 262         wxLogSysError(_("can't open file '%s'"), szFileName);
 263         return FALSE;
 264     }
 265     else {
 266         Attach(fd);
 267         return TRUE;
 268     }
 269 }
 270
 271 // close
 272 bool wxFile::Close()
 273 {
 274     if ( IsOpened() ) {
 275         if ( close(m_fd) == -1 ) {
 276             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 277             m_fd = fd_invalid;
 278             return FALSE;
 279         }
 280         else
 281             m_fd = fd_invalid;
 282     }
 283
 284     return TRUE;
 285 }
 286
 287 // ----------------------------------------------------------------------------
 288 // read/write
 289 // ----------------------------------------------------------------------------
 290
 291 // read
 292 off_t wxFile::Read(void *pBuf, off_t nCount)
 293 {
 294     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 295
 296 #ifdef __MWERKS__
 297     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 298 #else
 299     int iRc = ::read(m_fd, pBuf, nCount);
 300 #endif
 301     if ( iRc == -1 ) {
 302         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 303         return wxInvalidOffset;
 304     }
 305     else
 306         return (size_t)iRc;
 307 }
 308
 309 // write
 310 size_t wxFile::Write(const void *pBuf, size_t nCount)
 311 {
 312     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 313
 314 #ifdef __MWERKS__
 315 #if __MSL__ >= 0x6000
 316     int iRc = ::write(m_fd, (void*) pBuf, nCount);
 317 #else
 318     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 319 #endif
 320 #else
 321     int iRc = ::write(m_fd, pBuf, nCount);
 322 #endif
 323     if ( iRc == -1 ) {
 324         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 325         m_error = TRUE;
 326         return 0;
 327     }
 328     else
 329         return iRc;
 330 }
 331
 332 // flush
 333 bool wxFile::Flush()
 334 {
 335     if ( IsOpened() ) {
 336 #if defined(__VISUALC__) || wxHAVE_FSYNC
 337         if ( wxFsync(m_fd) == -1 )
 338         {
 339             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 340             return FALSE;
 341         }
 342 #else // no fsync
 343         // just do nothing
 344 #endif // fsync
 345     }
 346
 347     return TRUE;
 348 }
 349
 350 // ----------------------------------------------------------------------------
 351 // seek
 352 // ----------------------------------------------------------------------------
 353
 354 // seek
 355 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 356 {
 357     wxASSERT( IsOpened() );
 358
 359     int origin;
 360     switch ( mode ) {
 361         default:
 362             wxFAIL_MSG(_("unknown seek origin"));
 363
 364         case wxFromStart:
 365             origin = SEEK_SET;
 366             break;
 367
 368         case wxFromCurrent:
 369             origin = SEEK_CUR;
 370             break;
 371
 372         case wxFromEnd:
 373             origin = SEEK_END;
 374             break;
 375     }
 376
 377     int iRc = lseek(m_fd, ofs, origin);
 378     if ( iRc == -1 ) {
 379         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 380         return wxInvalidOffset;
 381     }
 382     else
 383         return (off_t)iRc;
 384 }
 385
 386 // get current off_t
 387 off_t wxFile::Tell() const
 388 {
 389     wxASSERT( IsOpened() );
 390
 391     int iRc = wxTell(m_fd);
 392     if ( iRc == -1 ) {
 393         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 394         return wxInvalidOffset;
 395     }
 396     else
 397         return (off_t)iRc;
 398 }
 399
 400 // get current file length
 401 off_t wxFile::Length() const
 402 {
 403     wxASSERT( IsOpened() );
 404
 405 #ifdef __VISUALC__
 406     int iRc = _filelength(m_fd);
 407 #else // !VC++
 408     int iRc = wxTell(m_fd);
 409     if ( iRc != -1 ) {
 410         // @ have to use const_cast :-(
 411         int iLen = ((wxFile *)this)->SeekEnd();
 412         if ( iLen != -1 ) {
 413             // restore old position
 414             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 415                 // error
 416                 iLen = -1;
 417             }
 418         }
 419
 420         iRc = iLen;
 421     }
 422 #endif  // VC++
 423
 424     if ( iRc == -1 ) {
 425         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 426         return wxInvalidOffset;
 427     }
 428     else
 429         return (off_t)iRc;
 430 }
 431
 432 // is end of file reached?
 433 bool wxFile::Eof() const
 434 {
 435     wxASSERT( IsOpened() );
 436
 437     int iRc;
 438
 439 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 440     // @@ this doesn't work, of course, on unseekable file descriptors
 441     off_t ofsCur = Tell(),
 442     ofsMax = Length();
 443     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 444         iRc = -1;
 445     else
 446         iRc = ofsCur == ofsMax;
 447 #else  // Windows and "native" compiler
 448     iRc = eof(m_fd);
 449 #endif // Windows/Unix
 450
 451     switch ( iRc ) {
 452         case 1:
 453             break;
 454
 455         case 0:
 456             return FALSE;
 457
 458         case -1:
 459             wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 460                 break;
 461
 462         default:
 463             wxFAIL_MSG(_("invalid eof() return value."));
 464     }
 465
 466     return TRUE;
 467 }
 468
 469 // ============================================================================
 470 // implementation of wxTempFile
 471 // ============================================================================
 472
 473 // ----------------------------------------------------------------------------
 474 // construction
 475 // ----------------------------------------------------------------------------
 476
 477 wxTempFile::wxTempFile(const wxString& strName)
 478 {
 479     Open(strName);
 480 }
 481
 482 bool wxTempFile::Open(const wxString& strName)
 483 {
 484     // we must have an absolute filename because otherwise CreateTempFileName()
 485     // would create the temp file in $TMP (i.e. the system standard location
 486     // for the temp files) which might be on another volume/drive/mount and
 487     // wxRename()ing it later to m_strName from Commit() would then fail
 488     //
 489     // with the absolute filename, the temp file is created in the same
 490     // directory as this one which ensures that wxRename() may work later
 491     wxFileName fn(strName);
 492     if ( !fn.IsAbsolute() )
 493     {
 494         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 495     }
 496
 497     m_strName = fn.GetFullPath();
 498
 499     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 500
 501     if ( m_strTemp.empty() )
 502     {
 503         // CreateTempFileName() failed
 504         return FALSE;
 505     }
 506
 507 #ifdef __UNIX__
 508     // the temp file should have the same permissions as the original one
 509     mode_t mode;
 510
 511     wxStructStat st;
 512     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 513     {
 514         mode = st.st_mode;
 515     }
 516     else
 517     {
 518         // file probably didn't exist, just give it the default mode _using_
 519         // user's umask (new files creation should respect umask)
 520         mode_t mask = umask(0777);
 521         mode = 0666 & ~mask;
 522         umask(mask);
 523     }
 524
 525     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 526     {
 527         wxLogSysError(_("Failed to set temporary file permissions"));
 528     }
 529 #endif // Unix
 530
 531     return TRUE;
 532 }
 533
 534 // ----------------------------------------------------------------------------
 535 // destruction
 536 // ----------------------------------------------------------------------------
 537
 538 wxTempFile::~wxTempFile()
 539 {
 540     if ( IsOpened() )
 541         Discard();
 542 }
 543
 544 bool wxTempFile::Commit()
 545 {
 546     m_file.Close();
 547
 548     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 549         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 550         return FALSE;
 551     }
 552
 553     if ( wxRename(m_strTemp, m_strName) != 0 ) {
 554         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 555         return FALSE;
 556     }
 557
 558     return TRUE;
 559 }
 560
 561 void wxTempFile::Discard()
 562 {
 563     m_file.Close();
 564     if ( wxRemove(m_strTemp) != 0 )
 565         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 566 }
 567
 568 #endif // wxUSE_FILE
 569