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 #ifdef __SALFORDC__
 103     #include <unix.h>
 104 #endif
 105
 106 // some broken compilers don't have 3rd argument in open() and creat()
 107 #ifdef __SALFORDC__
 108     #define ACCESS(access)
 109     #define stat    _stat
 110 #else // normal compiler
 111     #define ACCESS(access)  , (access)
 112 #endif // Salford C
 113
 114 // wxWidgets
 115 #ifndef WX_PRECOMP
 116     #include  "wx/string.h"
 117     #include  "wx/intl.h"
 118     #include  "wx/log.h"
 119 #endif // !WX_PRECOMP
 120
 121 #include  "wx/filename.h"
 122 #include  "wx/file.h"
 123 #include  "wx/filefn.h"
 124
 125 // there is no distinction between text and binary files under Unix, so define
 126 // O_BINARY as 0 if the system headers don't do it already
 127 #if defined(__UNIX__) && !defined(O_BINARY)
 128     #define   O_BINARY    (0)
 129 #endif  //__UNIX__
 130
 131 #ifdef __WXMSW__
 132     #include "wx/msw/mslu.h"
 133 #endif
 134
 135 #ifdef __WXWINCE__
 136     #include "wx/msw/private.h"
 137 #endif
 138
 139 #ifndef MAX_PATH
 140     #define MAX_PATH 512
 141 #endif
 142
 143 // ============================================================================
 144 // implementation of wxFile
 145 // ============================================================================
 146
 147 // ----------------------------------------------------------------------------
 148 // static functions
 149 // ----------------------------------------------------------------------------
 150
 151 bool wxFile::Exists(const wxChar *name)
 152 {
 153     return wxFileExists(name);
 154 }
 155
 156 bool wxFile::Access(const wxChar *name, OpenMode mode)
 157 {
 158     int how;
 159
 160     switch ( mode )
 161     {
 162         default:
 163             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 164             // fall through
 165
 166         case read:
 167             how = R_OK;
 168             break;
 169
 170         case write:
 171             how = W_OK;
 172             break;
 173
 174         case read_write:
 175             how = R_OK | W_OK;
 176             break;
 177     }
 178
 179     return wxAccess(name, how) == 0;
 180 }
 181
 182 // ----------------------------------------------------------------------------
 183 // opening/closing
 184 // ----------------------------------------------------------------------------
 185
 186 // ctors
 187 wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
 188 {
 189     m_fd = fd_invalid;
 190     m_error = false;
 191
 192     Open(szFileName, mode);
 193 }
 194
 195 // create the file, fail if it already exists and bOverwrite
 196 bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
 197 {
 198     // if bOverwrite we create a new file or truncate the existing one,
 199     // otherwise we only create the new file and fail if it already exists
 200 #if defined(__WXMAC__) && !defined(__UNIX__) && !wxUSE_UNICODE
 201     // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
 202     // int fd = open( szFileName , O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 203     int fd = creat( szFileName , accessMode);
 204 #else
 205     int fd = wxOpen( szFileName,
 206                      O_BINARY | O_WRONLY | O_CREAT |
 207                      (bOverwrite ? O_TRUNC : O_EXCL)
 208                      ACCESS(accessMode) );
 209 #endif
 210     if ( fd == -1 )
 211     {
 212         wxLogSysError(_("can't create file '%s'"), szFileName);
 213         return false;
 214     }
 215
 216     Attach(fd);
 217     return true;
 218 }
 219
 220 // open the file
 221 bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
 222 {
 223     int flags = O_BINARY;
 224
 225     switch ( mode )
 226     {
 227         case read:
 228             flags |= O_RDONLY;
 229             break;
 230
 231         case write_append:
 232             if ( wxFile::Exists(szFileName) )
 233             {
 234                 flags |= O_WRONLY | O_APPEND;
 235                 break;
 236             }
 237             //else: fall through as write_append is the same as write if the
 238             //      file doesn't exist
 239
 240         case write:
 241             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 242             break;
 243
 244         case write_excl:
 245             flags |= O_WRONLY | O_CREAT | O_EXCL;
 246             break;
 247
 248         case read_write:
 249             flags |= O_RDWR;
 250             break;
 251     }
 252
 253 #ifdef __WINDOWS__
 254     // only read/write bits for "all" are supported by this function under
 255     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 256     // accessMode, so clear them as they have at best no effect anyhow
 257     accessMode &= wxS_IRUSR | wxS_IWUSR;
 258 #endif // __WINDOWS__
 259
 260     int fd = wxOpen( szFileName, flags ACCESS(accessMode));
 261
 262     if ( fd == -1 )
 263     {
 264         wxLogSysError(_("can't open file '%s'"), szFileName);
 265         return false;
 266     }
 267
 268     Attach(fd);
 269     return true;
 270 }
 271
 272 // close
 273 bool wxFile::Close()
 274 {
 275     if ( IsOpened() ) {
 276         if (wxClose(m_fd) == -1)
 277         {
 278             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 279             m_fd = fd_invalid;
 280             return false;
 281         }
 282         else
 283             m_fd = fd_invalid;
 284     }
 285
 286     return true;
 287 }
 288
 289 // ----------------------------------------------------------------------------
 290 // read/write
 291 // ----------------------------------------------------------------------------
 292
 293 // read
 294 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 295 {
 296     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 297
 298     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 299
 300     if ( iRc == -1 )
 301     {
 302         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 303         return wxInvalidOffset;
 304     }
 305
 306     return 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     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 315
 316     if ( iRc == -1 )
 317     {
 318         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 319         m_error = true;
 320         iRc = 0;
 321     }
 322
 323     return iRc;
 324 }
 325
 326 // flush
 327 bool wxFile::Flush()
 328 {
 329 #ifdef HAVE_FSYNC
 330     // fsync() only works on disk files and returns errors for pipes, don't
 331     // call it then
 332     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 333     {
 334         if ( wxFsync(m_fd) == -1 )
 335         {
 336             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 337             return false;
 338         }
 339     }
 340 #endif // HAVE_FSYNC
 341
 342     return true;
 343 }
 344
 345 // ----------------------------------------------------------------------------
 346 // seek
 347 // ----------------------------------------------------------------------------
 348
 349 // seek
 350 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 351 {
 352     wxASSERT_MSG( IsOpened(), _T("can't seek on closed file") );
 353     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 354                  wxInvalidOffset,
 355                  _T("invalid absolute file offset") );
 356
 357     int origin;
 358     switch ( mode ) {
 359         default:
 360             wxFAIL_MSG(_("unknown seek origin"));
 361
 362         case wxFromStart:
 363             origin = SEEK_SET;
 364             break;
 365
 366         case wxFromCurrent:
 367             origin = SEEK_CUR;
 368             break;
 369
 370         case wxFromEnd:
 371             origin = SEEK_END;
 372             break;
 373     }
 374
 375     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 376     if ( iRc == wxInvalidOffset )
 377     {
 378         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 379     }
 380
 381     return iRc;
 382 }
 383
 384 // get current file offset
 385 wxFileOffset wxFile::Tell() const
 386 {
 387     wxASSERT( IsOpened() );
 388
 389     wxFileOffset iRc = wxTell(m_fd);
 390     if ( iRc == wxInvalidOffset )
 391     {
 392         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 393     }
 394
 395     return iRc;
 396 }
 397
 398 // get current file length
 399 wxFileOffset wxFile::Length() const
 400 {
 401     wxASSERT( IsOpened() );
 402
 403     wxFileOffset iRc = Tell();
 404     if ( iRc != wxInvalidOffset ) {
 405         // have to use const_cast :-(
 406         wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
 407         if ( iLen != wxInvalidOffset ) {
 408             // restore old position
 409             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 410                 // error
 411                 iLen = wxInvalidOffset;
 412             }
 413         }
 414
 415         iRc = iLen;
 416     }
 417
 418     if ( iRc == wxInvalidOffset )
 419     {
 420         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 421     }
 422
 423     return iRc;
 424 }
 425
 426 // is end of file reached?
 427 bool wxFile::Eof() const
 428 {
 429     wxASSERT( IsOpened() );
 430
 431     wxFileOffset iRc;
 432
 433 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
 434     // @@ this doesn't work, of course, on unseekable file descriptors
 435     wxFileOffset ofsCur = Tell(),
 436     ofsMax = Length();
 437     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 438         iRc = wxInvalidOffset;
 439     else
 440         iRc = ofsCur == ofsMax;
 441 #else  // Windows and "native" compiler
 442     iRc = wxEof(m_fd);
 443 #endif // Windows/Unix
 444
 445     if ( iRc == 1)
 446         {}
 447     else if ( iRc == 0 )
 448         return false;
 449     else if ( iRc == wxInvalidOffset )
 450         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 451     else
 452         wxFAIL_MSG(_("invalid eof() return value."));
 453
 454     return true;
 455 }
 456
 457 // ============================================================================
 458 // implementation of wxTempFile
 459 // ============================================================================
 460
 461 // ----------------------------------------------------------------------------
 462 // construction
 463 // ----------------------------------------------------------------------------
 464
 465 wxTempFile::wxTempFile(const wxString& strName)
 466 {
 467     Open(strName);
 468 }
 469
 470 bool wxTempFile::Open(const wxString& strName)
 471 {
 472     // we must have an absolute filename because otherwise CreateTempFileName()
 473     // would create the temp file in $TMP (i.e. the system standard location
 474     // for the temp files) which might be on another volume/drive/mount and
 475     // wxRename()ing it later to m_strName from Commit() would then fail
 476     //
 477     // with the absolute filename, the temp file is created in the same
 478     // directory as this one which ensures that wxRename() may work later
 479     wxFileName fn(strName);
 480     if ( !fn.IsAbsolute() )
 481     {
 482         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 483     }
 484
 485     m_strName = fn.GetFullPath();
 486
 487     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 488
 489     if ( m_strTemp.empty() )
 490     {
 491         // CreateTempFileName() failed
 492         return false;
 493     }
 494
 495 #ifdef __UNIX__
 496     // the temp file should have the same permissions as the original one
 497     mode_t mode;
 498
 499     wxStructStat st;
 500     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 501     {
 502         mode = st.st_mode;
 503     }
 504     else
 505     {
 506         // file probably didn't exist, just give it the default mode _using_
 507         // user's umask (new files creation should respect umask)
 508         mode_t mask = umask(0777);
 509         mode = 0666 & ~mask;
 510         umask(mask);
 511     }
 512
 513     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 514     {
 515 #ifndef __OS2__
 516         wxLogSysError(_("Failed to set temporary file permissions"));
 517 #endif
 518     }
 519 #endif // Unix
 520
 521     return true;
 522 }
 523
 524 // ----------------------------------------------------------------------------
 525 // destruction
 526 // ----------------------------------------------------------------------------
 527
 528 wxTempFile::~wxTempFile()
 529 {
 530     if ( IsOpened() )
 531         Discard();
 532 }
 533
 534 bool wxTempFile::Commit()
 535 {
 536     m_file.Close();
 537
 538     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 539         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 540         return false;
 541     }
 542
 543     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 544         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 545         return false;
 546     }
 547
 548     return true;
 549 }
 550
 551 void wxTempFile::Discard()
 552 {
 553     m_file.Close();
 554     if ( wxRemove(m_strTemp) != 0 )
 555         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 556 }
 557
 558 #endif // wxUSE_FILE
 559