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(__WXWINE__) && !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     #define   W_OK        2
  75     #define   R_OK        4
  76 #elif (defined(__WXSTUBS__))
  77     // Have to ifdef this for different environments
  78     #include <io.h>
  79 #elif (defined(__WXMAC__))
  80 #if __MSL__ < 0x6000
  81     int access( const char *path, int mode ) { return 0 ; }
  82 #else
  83     int _access( const char *path, int mode ) { return 0 ; }
  84 #endif
  85     char* mktemp( char * path ) { return path ;}
  86     #include <stat.h>
  87     #define   W_OK        2
  88     #define   R_OK        4
  89     #include  <unistd.h>
  90 #else
  91     #error  "Please specify the header with file functions declarations."
  92 #endif  //Win/UNIX
  93
  94 #include  <stdio.h>       // SEEK_xxx constants
  95 #include  <fcntl.h>       // O_RDONLY &c
  96
  97 #ifndef __MWERKS__
  98     #include  <sys/types.h>   // needed for stat
  99     #include  <sys/stat.h>    // stat
 100 #elif ( defined(__MWERKS__) && defined(__WXMSW__) )
 101     #include  <sys/types.h>   // needed for stat
 102     #include  <sys/stat.h>    // stat
 103 #endif
 104
 105 #if defined(__BORLANDC__) || defined(_MSC_VER)
 106     #define   W_OK        2
 107     #define   R_OK        4
 108 #endif
 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
 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 bool wxFile::Exists(const wxChar *name)
 154 {
 155     wxStructStat st;
 156     return !wxAccess(name, 0) &&
 157            !wxStat(name, &st) &&
 158            (st.st_mode & S_IFREG);
 159 }
 160
 161 bool wxFile::Access(const wxChar *name, OpenMode mode)
 162 {
 163     int how = 0;
 164
 165     switch ( mode ) {
 166         case read:
 167             how = R_OK;
 168             break;
 169
 170         case write:
 171             how = W_OK;
 172             break;
 173
 174         default:
 175             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 176     }
 177
 178     return wxAccess( name, how) == 0;
 179 }
 180
 181 // ----------------------------------------------------------------------------
 182 // opening/closing
 183 // ----------------------------------------------------------------------------
 184
 185 // ctors
 186 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 187 {
 188     m_fd = fd_invalid;
 189     m_error = FALSE;
 190
 191     Open(szFileName, mode);
 192 }
 193
 194 // create the file, fail if it already exists and bOverwrite
 195 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 196 {
 197     // if bOverwrite we create a new file or truncate the existing one,
 198     // otherwise we only create the new file and fail if it already exists
 199 #if defined(__WXMAC__) && !defined(__UNIX__)
 200     // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
 201     // int fd = open(wxUnix2MacFilename( szFileName ), O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 202     int fd = creat( szFileName , accessMode);
 203 #else
 204     int fd = wxOpen( szFileName,
 205                      O_BINARY | O_WRONLY | O_CREAT |
 206                      (bOverwrite ? O_TRUNC : O_EXCL)
 207                      ACCESS(accessMode) );
 208 #endif
 209     if ( fd == -1 )
 210     {
 211         wxLogSysError(_("can't create file '%s'"), szFileName);
 212         return FALSE;
 213     }
 214     else
 215     {
 216         Attach(fd);
 217         return TRUE;
 218     }
 219 }
 220
 221 // open the file
 222 bool wxFile::Open(const wxChar *szFileName, 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(szFileName) )
 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     int fd = wxOpen( szFileName, flags ACCESS(accessMode));
 255     if ( fd == -1 )
 256     {
 257         wxLogSysError(_("can't open file '%s'"), szFileName);
 258         return FALSE;
 259     }
 260     else {
 261         Attach(fd);
 262         return TRUE;
 263     }
 264 }
 265
 266 // close
 267 bool wxFile::Close()
 268 {
 269     if ( IsOpened() ) {
 270         if ( close(m_fd) == -1 ) {
 271             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 272             m_fd = fd_invalid;
 273             return FALSE;
 274         }
 275         else
 276             m_fd = fd_invalid;
 277     }
 278
 279     return TRUE;
 280 }
 281
 282 // ----------------------------------------------------------------------------
 283 // read/write
 284 // ----------------------------------------------------------------------------
 285
 286 // read
 287 off_t wxFile::Read(void *pBuf, off_t nCount)
 288 {
 289     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 290
 291 #ifdef __MWERKS__
 292     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 293 #else
 294     int iRc = ::read(m_fd, pBuf, nCount);
 295 #endif
 296     if ( iRc == -1 ) {
 297         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 298         return wxInvalidOffset;
 299     }
 300     else
 301         return (size_t)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 #ifdef __MWERKS__
 310 #if __MSL__ >= 0x6000
 311     int iRc = ::write(m_fd, (void*) pBuf, nCount);
 312 #else
 313     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 314 #endif
 315 #else
 316     int iRc = ::write(m_fd, pBuf, nCount);
 317 #endif
 318     if ( iRc == -1 ) {
 319         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 320         m_error = TRUE;
 321         return 0;
 322     }
 323     else
 324         return iRc;
 325 }
 326
 327 // flush
 328 bool wxFile::Flush()
 329 {
 330     if ( IsOpened() ) {
 331 #if defined(__VISUALC__) || wxHAVE_FSYNC
 332         if ( wxFsync(m_fd) == -1 )
 333         {
 334             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 335             return FALSE;
 336         }
 337 #else // no fsync
 338         // just do nothing
 339 #endif // fsync
 340     }
 341
 342     return TRUE;
 343 }
 344
 345 // ----------------------------------------------------------------------------
 346 // seek
 347 // ----------------------------------------------------------------------------
 348
 349 // seek
 350 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 351 {
 352     wxASSERT( IsOpened() );
 353
 354     int origin;
 355     switch ( mode ) {
 356         default:
 357             wxFAIL_MSG(_("unknown seek origin"));
 358
 359         case wxFromStart:
 360             origin = SEEK_SET;
 361             break;
 362
 363         case wxFromCurrent:
 364             origin = SEEK_CUR;
 365             break;
 366
 367         case wxFromEnd:
 368             origin = SEEK_END;
 369             break;
 370     }
 371
 372     int iRc = lseek(m_fd, ofs, origin);
 373     if ( iRc == -1 ) {
 374         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 375         return wxInvalidOffset;
 376     }
 377     else
 378         return (off_t)iRc;
 379 }
 380
 381 // get current off_t
 382 off_t wxFile::Tell() const
 383 {
 384     wxASSERT( IsOpened() );
 385
 386     int iRc = wxTell(m_fd);
 387     if ( iRc == -1 ) {
 388         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 389         return wxInvalidOffset;
 390     }
 391     else
 392         return (off_t)iRc;
 393 }
 394
 395 // get current file length
 396 off_t wxFile::Length() const
 397 {
 398     wxASSERT( IsOpened() );
 399
 400 #ifdef __VISUALC__
 401     int iRc = _filelength(m_fd);
 402 #else // !VC++
 403     int iRc = wxTell(m_fd);
 404     if ( iRc != -1 ) {
 405         // @ have to use const_cast :-(
 406         int iLen = ((wxFile *)this)->SeekEnd();
 407         if ( iLen != -1 ) {
 408             // restore old position
 409             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 410                 // error
 411                 iLen = -1;
 412             }
 413         }
 414
 415         iRc = iLen;
 416     }
 417 #endif  // VC++
 418
 419     if ( iRc == -1 ) {
 420         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 421         return wxInvalidOffset;
 422     }
 423     else
 424         return (off_t)iRc;
 425 }
 426
 427 // is end of file reached?
 428 bool wxFile::Eof() const
 429 {
 430     wxASSERT( IsOpened() );
 431
 432     int iRc;
 433
 434 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 435     // @@ this doesn't work, of course, on unseekable file descriptors
 436     off_t ofsCur = Tell(),
 437     ofsMax = Length();
 438     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 439         iRc = -1;
 440     else
 441         iRc = ofsCur == ofsMax;
 442 #else  // Windows and "native" compiler
 443     iRc = eof(m_fd);
 444 #endif // Windows/Unix
 445
 446     switch ( iRc ) {
 447         case 1:
 448             break;
 449
 450         case 0:
 451             return FALSE;
 452
 453         case -1:
 454             wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 455                 break;
 456
 457         default:
 458             wxFAIL_MSG(_("invalid eof() return value."));
 459     }
 460
 461     return TRUE;
 462 }
 463
 464 // ============================================================================
 465 // implementation of wxTempFile
 466 // ============================================================================
 467
 468 // ----------------------------------------------------------------------------
 469 // construction
 470 // ----------------------------------------------------------------------------
 471
 472 wxTempFile::wxTempFile(const wxString& strName)
 473 {
 474     Open(strName);
 475 }
 476
 477 bool wxTempFile::Open(const wxString& strName)
 478 {
 479     // we must have an absolute filename because otherwise CreateTempFileName()
 480     // would create the temp file in $TMP (i.e. the system standard location
 481     // for the temp files) which might be on another volume/drive/mount and
 482     // wxRename()ing it later to m_strName from Commit() would then fail
 483     //
 484     // with the absolute filename, the temp file is created in the same
 485     // directory as this one which ensures that wxRename() may work later
 486     wxFileName fn(strName);
 487     if ( !fn.IsAbsolute() )
 488     {
 489         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 490     }
 491
 492     m_strName = fn.GetFullPath();
 493
 494     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 495
 496     if ( m_strTemp.empty() )
 497     {
 498         // CreateTempFileName() failed
 499         return FALSE;
 500     }
 501
 502 #ifdef __UNIX__
 503     // the temp file should have the same permissions as the original one
 504     mode_t mode;
 505
 506     wxStructStat st;
 507     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 508     {
 509         mode = st.st_mode;
 510     }
 511     else
 512     {
 513         // file probably didn't exist, just give it the default mode _using_
 514         // user's umask (new files creation should respect umask)
 515         mode_t mask = umask(0777);
 516         mode = 0666 & ~mask;
 517         umask(mask);
 518     }
 519
 520     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 521     {
 522         wxLogSysError(_("Failed to set temporary file permissions"));
 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 ( wxRename(m_strTemp, m_strName) != 0 ) {
 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