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     #include  <windows.h>     // for GetTempFileName
  58 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  59     #include  <unistd.h>
  60     #ifdef __GNUWIN32__
  61         #include <windows.h>
  62     #endif
  63 #elif (defined(__WXPM__))
  64     #include <io.h>
  65     #define   W_OK        2
  66     #define   R_OK        4
  67 #elif (defined(__WXSTUBS__))
  68     // Have to ifdef this for different environments
  69     #include <io.h>
  70 #elif (defined(__WXMAC__))
  71 #if __MSL__ < 0x6000
  72     int access( const char *path, int mode ) { return 0 ; }
  73 #else
  74     int _access( const char *path, int mode ) { return 0 ; }
  75 #endif
  76     char* mktemp( char * path ) { return path ;}
  77     #include <stat.h>
  78     #define   W_OK        2
  79     #define   R_OK        4
  80     #include  <unistd.h>
  81 #else
  82     #error  "Please specify the header with file functions declarations."
  83 #endif  //Win/UNIX
  84
  85 #include  <stdio.h>       // SEEK_xxx constants
  86 #include  <fcntl.h>       // O_RDONLY &c
  87
  88 #ifndef __MWERKS__
  89     #include  <sys/types.h>   // needed for stat
  90     #include  <sys/stat.h>    // stat
  91 #elif ( defined(__MWERKS__) && defined(__WXMSW__) )
  92     #include  <sys/types.h>   // needed for stat
  93     #include  <sys/stat.h>    // stat
  94 #endif
  95
  96 #if defined(__BORLANDC__) || defined(_MSC_VER)
  97     #define   W_OK        2
  98     #define   R_OK        4
  99 #endif
 100
 101 // there is no distinction between text and binary files under Unix, so define
 102 // O_BINARY as 0 if the system headers don't do it already
 103 #if defined(__UNIX__) && !defined(O_BINARY)
 104     #define   O_BINARY    (0)
 105 #endif  //__UNIX__
 106
 107 #ifdef __SALFORDC__
 108     #include <unix.h>
 109 #endif
 110
 111 #ifndef MAX_PATH
 112     #define MAX_PATH 512
 113 #endif
 114
 115 // some broken compilers don't have 3rd argument in open() and creat()
 116 #ifdef __SALFORDC__
 117     #define ACCESS(access)
 118     #define stat    _stat
 119 #else // normal compiler
 120     #define ACCESS(access)  , (access)
 121 #endif // Salford C
 122
 123 // wxWindows
 124 #include  "wx/string.h"
 125 #include  "wx/intl.h"
 126 #include  "wx/file.h"
 127 #include  "wx/log.h"
 128
 129 // ============================================================================
 130 // implementation of wxFile
 131 // ============================================================================
 132
 133 // ----------------------------------------------------------------------------
 134 // static functions
 135 // ----------------------------------------------------------------------------
 136 bool wxFile::Exists(const wxChar *name)
 137 {
 138     wxStructStat st;
 139 #if wxUSE_UNICODE && wxMBFILES
 140     wxCharBuffer fname = wxConvFile.cWC2MB(name);
 141
 142     return !wxAccess(fname, 0) &&
 143            !wxStat(wxMBSTRINGCAST fname, &st) &&
 144            (st.st_mode & S_IFREG);
 145
 146 #else
 147     return !wxAccess(name, 0) &&
 148            !wxStat(name, &st) &&
 149            (st.st_mode & S_IFREG);
 150 #endif
 151 }
 152
 153 bool wxFile::Access(const wxChar *name, OpenMode mode)
 154 {
 155     int how = 0;
 156
 157     switch ( mode ) {
 158         case read:
 159             how = R_OK;
 160             break;
 161
 162         case write:
 163             how = W_OK;
 164             break;
 165
 166         default:
 167             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 168     }
 169
 170     return wxAccess(wxFNCONV(name), how) == 0;
 171 }
 172
 173 // ----------------------------------------------------------------------------
 174 // opening/closing
 175 // ----------------------------------------------------------------------------
 176
 177 // ctors
 178 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 179 {
 180     m_fd = fd_invalid;
 181     m_error = FALSE;
 182
 183     Open(szFileName, mode);
 184 }
 185
 186 // create the file, fail if it already exists and bOverwrite
 187 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 188 {
 189     // if bOverwrite we create a new file or truncate the existing one,
 190     // otherwise we only create the new file and fail if it already exists
 191 #if defined(__WXMAC__) && !defined(__UNIX__)
 192   // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
 193   // int fd = open(wxUnix2MacFilename( szFileName ), O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 194   int fd = creat( szFileName , accessMode);
 195 #else
 196     int fd = wxOpen(wxFNCONV(szFileName),
 197                     O_BINARY | O_WRONLY | O_CREAT |
 198                     (bOverwrite ? O_TRUNC : O_EXCL)
 199                     ACCESS(accessMode));
 200 #endif
 201     if ( fd == -1 ) {
 202         wxLogSysError(_("can't create file '%s'"), szFileName);
 203         return FALSE;
 204     }
 205     else {
 206         Attach(fd);
 207         return TRUE;
 208     }
 209 }
 210
 211 // open the file
 212 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 213 {
 214     int flags = O_BINARY;
 215
 216     switch ( mode ) {
 217         case read:
 218             flags |= O_RDONLY;
 219             break;
 220
 221         case write_append:
 222             if ( wxFile::Exists(szFileName) )
 223             {
 224                 flags |= O_WRONLY | O_APPEND;
 225                 break;
 226             }
 227             //else: fall through as write_append is the same as write if the
 228             //      file doesn't exist
 229
 230         case write:
 231             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 232             break;
 233
 234         case read_write:
 235             flags |= O_RDWR;
 236             break;
 237     }
 238
 239     int fd = wxOpen(wxFNCONV(szFileName), flags ACCESS(accessMode));
 240     if ( fd == -1 ) {
 241         wxLogSysError(_("can't open file '%s'"), szFileName);
 242         return FALSE;
 243     }
 244     else {
 245         Attach(fd);
 246         return TRUE;
 247     }
 248 }
 249
 250 // close
 251 bool wxFile::Close()
 252 {
 253     if ( IsOpened() ) {
 254         if ( close(m_fd) == -1 ) {
 255             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 256             m_fd = fd_invalid;
 257             return FALSE;
 258         }
 259         else
 260             m_fd = fd_invalid;
 261     }
 262
 263     return TRUE;
 264 }
 265
 266 // ----------------------------------------------------------------------------
 267 // read/write
 268 // ----------------------------------------------------------------------------
 269
 270 // read
 271 off_t wxFile::Read(void *pBuf, off_t nCount)
 272 {
 273     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 274
 275 #ifdef __MWERKS__
 276     int iRc = ::read(m_fd, (char*) pBuf, nCount);
 277 #else
 278     int iRc = ::read(m_fd, pBuf, nCount);
 279 #endif
 280     if ( iRc == -1 ) {
 281         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 282         return wxInvalidOffset;
 283     }
 284     else
 285         return (size_t)iRc;
 286 }
 287
 288 // write
 289 size_t wxFile::Write(const void *pBuf, size_t nCount)
 290 {
 291     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 292
 293 #ifdef __MWERKS__
 294 #if __MSL__ >= 0x6000
 295     int iRc = ::write(m_fd, (void*) pBuf, nCount);
 296 #else
 297     int iRc = ::write(m_fd, (const char*) pBuf, nCount);
 298 #endif
 299 #else
 300     int iRc = ::write(m_fd, pBuf, nCount);
 301 #endif
 302     if ( iRc == -1 ) {
 303         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 304         m_error = TRUE;
 305         return 0;
 306     }
 307     else
 308         return iRc;
 309 }
 310
 311 // flush
 312 bool wxFile::Flush()
 313 {
 314     if ( IsOpened() ) {
 315 #if defined(__VISUALC__) || wxHAVE_FSYNC
 316         if ( wxFsync(m_fd) == -1 )
 317         {
 318             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 319             return FALSE;
 320         }
 321 #else // no fsync
 322         // just do nothing
 323 #endif // fsync
 324     }
 325
 326     return TRUE;
 327 }
 328
 329 // ----------------------------------------------------------------------------
 330 // seek
 331 // ----------------------------------------------------------------------------
 332
 333 // seek
 334 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 335 {
 336     wxASSERT( IsOpened() );
 337
 338     int origin;
 339     switch ( mode ) {
 340         default:
 341             wxFAIL_MSG(_("unknown seek origin"));
 342
 343         case wxFromStart:
 344             origin = SEEK_SET;
 345             break;
 346
 347         case wxFromCurrent:
 348             origin = SEEK_CUR;
 349             break;
 350
 351         case wxFromEnd:
 352             origin = SEEK_END;
 353             break;
 354     }
 355
 356     int iRc = lseek(m_fd, ofs, origin);
 357     if ( iRc == -1 ) {
 358         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 359         return wxInvalidOffset;
 360     }
 361     else
 362         return (off_t)iRc;
 363 }
 364
 365 // get current off_t
 366 off_t wxFile::Tell() const
 367 {
 368     wxASSERT( IsOpened() );
 369
 370     int iRc = wxTell(m_fd);
 371     if ( iRc == -1 ) {
 372         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 373         return wxInvalidOffset;
 374     }
 375     else
 376         return (off_t)iRc;
 377 }
 378
 379 // get current file length
 380 off_t wxFile::Length() const
 381 {
 382     wxASSERT( IsOpened() );
 383
 384 #ifdef __VISUALC__
 385     int iRc = _filelength(m_fd);
 386 #else // !VC++
 387     int iRc = wxTell(m_fd);
 388     if ( iRc != -1 ) {
 389         // @ have to use const_cast :-(
 390         int iLen = ((wxFile *)this)->SeekEnd();
 391         if ( iLen != -1 ) {
 392             // restore old position
 393             if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 394                 // error
 395                 iLen = -1;
 396             }
 397         }
 398
 399         iRc = iLen;
 400     }
 401 #endif  // VC++
 402
 403     if ( iRc == -1 ) {
 404         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 405         return wxInvalidOffset;
 406     }
 407     else
 408         return (off_t)iRc;
 409 }
 410
 411 // is end of file reached?
 412 bool wxFile::Eof() const
 413 {
 414     wxASSERT( IsOpened() );
 415
 416     int iRc;
 417
 418 #if defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 419     // @@ this doesn't work, of course, on unseekable file descriptors
 420     off_t ofsCur = Tell(),
 421     ofsMax = Length();
 422     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 423         iRc = -1;
 424     else
 425         iRc = ofsCur == ofsMax;
 426 #else  // Windows and "native" compiler
 427     iRc = eof(m_fd);
 428 #endif // Windows/Unix
 429
 430     switch ( iRc ) {
 431         case 1:
 432             break;
 433
 434         case 0:
 435             return FALSE;
 436
 437         case -1:
 438             wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 439                 break;
 440
 441         default:
 442             wxFAIL_MSG(_("invalid eof() return value."));
 443     }
 444
 445     return TRUE;
 446 }
 447
 448 // ============================================================================
 449 // implementation of wxTempFile
 450 // ============================================================================
 451
 452 // ----------------------------------------------------------------------------
 453 // construction
 454 // ----------------------------------------------------------------------------
 455 wxTempFile::wxTempFile(const wxString& strName)
 456 {
 457     Open(strName);
 458 }
 459
 460 bool wxTempFile::Open(const wxString& strName)
 461 {
 462     m_strName = strName;
 463
 464     // we want to create the file in the same directory as strName because
 465     // otherwise rename() in Commit() might not work (if the files are on
 466     // different partitions for example). Unfortunately, the only standard
 467     // (POSIX) temp file creation function tmpnam() can't do it.
 468 #if defined(__UNIX__) || defined(__WXSTUBS__)|| defined( __WXMAC__ )
 469     static const wxChar *szMktempSuffix = wxT("XXXXXX");
 470     m_strTemp << strName << szMktempSuffix;
 471     // can use the cast because length doesn't change
 472     mktemp(wxMBSTRINGCAST m_strTemp.mb_str());
 473 #elif  defined(__WXPM__)
 474     // for now just create a file
 475     // future enhancements can be to set some extended attributes for file systems
 476     // OS/2 supports that have them (HPFS, FAT32) and security (HPFS386)
 477     static const wxChar *szMktempSuffix = wxT("XXX");
 478     m_strTemp << strName << szMktempSuffix;
 479     // Temporarily remove - MN
 480     #ifndef __WATCOMC__
 481     ::DosCreateDir(m_strTemp.GetWriteBuf(MAX_PATH), NULL);
 482     #endif
 483 #else // Windows
 484     wxString strPath;
 485     wxSplitPath(strName, &strPath, NULL, NULL);
 486     if ( strPath.IsEmpty() )
 487         strPath = wxT('.');  // GetTempFileName will fail if we give it empty string
 488 #ifdef __WIN32__
 489     if ( !GetTempFileName(strPath, wxT("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 490 #else
 491         // Not sure why MSVC++ 1.5 header defines first param as BYTE - bug?
 492         if ( !GetTempFileName((BYTE) (DWORD)(const wxChar*) strPath, wxT("wx_"),0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 493 #endif
 494             wxLogLastError(wxT("GetTempFileName"));
 495     m_strTemp.UngetWriteBuf();
 496 #endif  // Windows/Unix
 497
 498     int access = wxS_DEFAULT;
 499 #ifdef __UNIX__
 500     // create the file with the same mode as the original one under Unix
 501     mode_t umaskOld = 0; // just to suppress compiler warning
 502     bool changedUmask;
 503
 504     wxStructStat st;
 505     if ( stat(strName.fn_str(), &st) == 0 )
 506     {
 507         // this assumes that only lower bits of st_mode contain the access
 508         // rights, but it's true for at least all Unices which have S_IXXXX()
 509         // macros, so should not be less portable than using (not POSIX)
 510         // S_IFREG &c
 511         access = st.st_mode & 0777;
 512
 513         // we want to create the file with exactly the same access rights as
 514         // the original one, so disable the user's umask for the moment
 515         umaskOld = umask(0);
 516         changedUmask = TRUE;
 517     }
 518     else
 519     {
 520         // file probably didn't exist, just create with default mode _using_
 521         // user's umask (new files creation should respet umask)
 522         changedUmask = FALSE;
 523     }
 524 #endif // Unix
 525
 526     bool ok = m_file.Open(m_strTemp, wxFile::write, access);
 527
 528 #ifdef __UNIX__
 529     if ( changedUmask )
 530     {
 531         // restore umask now that the file is created
 532         (void)umask(umaskOld);
 533     }
 534 #endif // Unix
 535
 536     return ok;
 537 }
 538
 539 // ----------------------------------------------------------------------------
 540 // destruction
 541 // ----------------------------------------------------------------------------
 542
 543 wxTempFile::~wxTempFile()
 544 {
 545     if ( IsOpened() )
 546         Discard();
 547 }
 548
 549 bool wxTempFile::Commit()
 550 {
 551     m_file.Close();
 552
 553     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 554         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 555         return FALSE;
 556     }
 557
 558     if ( wxRename(m_strTemp, m_strName) != 0 ) {
 559         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 560         return FALSE;
 561     }
 562
 563     return TRUE;
 564 }
 565
 566 void wxTempFile::Discard()
 567 {
 568     m_file.Close();
 569     if ( wxRemove(m_strTemp) != 0 )
 570         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 571 }
 572
 573 #endif
 574