src/common/file.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/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 #define   WIN32_LEAN_AND_MEAN
  30 #define   NOSERVICE
  31 #define   NOIME
  32 #define   NOATOM
  33 #define   NOGDI
  34 #define   NOGDICAPMASKS
  35 #define   NOMETAFILE
  36 #define   NOMINMAX
  37 #define   NOMSG
  38 #define   NOOPENFILE
  39 #define   NORASTEROPS
  40 #define   NOSCROLL
  41 #define   NOSOUND
  42 #define   NOSYSMETRICS
  43 #define   NOTEXTMETRIC
  44 #define   NOWH
  45 #define   NOCOMM
  46 #define   NOKANJI
  47 #define   NOCRYPT
  48 #define   NOMCX
  49
  50 #elif defined(__WXMSW__) && defined(__WXWINCE__)
  51     #include  "wx/msw/missing.h"
  52 #elif (defined(__OS2__))
  53     #include <io.h>
  54 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  55     #include  <unistd.h>
  56     #include  <time.h>
  57     #include  <sys/stat.h>
  58     #ifdef __GNUWIN32__
  59         #include "wx/msw/wrapwin.h"
  60     #endif
  61 #elif defined(__DOS__)
  62     #if defined(__WATCOMC__)
  63        #include <io.h>
  64     #elif defined(__DJGPP__)
  65        #include <io.h>
  66        #include <unistd.h>
  67        #include <stdio.h>
  68     #else
  69         #error  "Please specify the header with file functions declarations."
  70     #endif
  71 #elif (defined(__WXSTUBS__))
  72     // Have to ifdef this for different environments
  73     #include <io.h>
  74 #elif (defined(__WXMAC__))
  75 #if __MSL__ < 0x6000
  76     int access( const char *path, int mode ) { return 0 ; }
  77 #else
  78     int _access( const char *path, int mode ) { return 0 ; }
  79 #endif
  80     char* mktemp( char * path ) { return path ;}
  81     #include <stat.h>
  82     #include <unistd.h>
  83 #else
  84     #error  "Please specify the header with file functions declarations."
  85 #endif  //Win/UNIX
  86
  87 #include  <stdio.h>       // SEEK_xxx constants
  88
  89 #ifndef __WXWINCE__
  90     #include <errno.h>
  91 #endif
  92
  93 // Windows compilers don't have these constants
  94 #ifndef W_OK
  95     enum
  96     {
  97         F_OK = 0,   // test for existence
  98         X_OK = 1,   //          execute permission
  99         W_OK = 2,   //          write
 100         R_OK = 4    //          read
 101     };
 102 #endif // W_OK
 103
 104 // wxWidgets
 105 #ifndef WX_PRECOMP
 106     #include  "wx/string.h"
 107     #include  "wx/intl.h"
 108     #include  "wx/log.h"
 109     #include "wx/crt.h"
 110 #endif // !WX_PRECOMP
 111
 112 #include  "wx/filename.h"
 113 #include  "wx/file.h"
 114 #include  "wx/filefn.h"
 115
 116 // there is no distinction between text and binary files under Unix, so define
 117 // O_BINARY as 0 if the system headers don't do it already
 118 #if defined(__UNIX__) && !defined(O_BINARY)
 119     #define   O_BINARY    (0)
 120 #endif  //__UNIX__
 121
 122 #ifdef __WXMSW__
 123     #include "wx/msw/mslu.h"
 124 #endif
 125
 126 #ifdef __WXWINCE__
 127     #include "wx/msw/private.h"
 128 #endif
 129
 130 #ifndef MAX_PATH
 131     #define MAX_PATH 512
 132 #endif
 133
 134 // ============================================================================
 135 // implementation of wxFile
 136 // ============================================================================
 137
 138 // ----------------------------------------------------------------------------
 139 // static functions
 140 // ----------------------------------------------------------------------------
 141
 142 bool wxFile::Exists(const wxString& name)
 143 {
 144     return wxFileExists(name);
 145 }
 146
 147 bool wxFile::Access(const wxString& name, OpenMode mode)
 148 {
 149     int how;
 150
 151     switch ( mode )
 152     {
 153         default:
 154             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 155             // fall through
 156
 157         case read:
 158             how = R_OK;
 159             break;
 160
 161         case write:
 162             how = W_OK;
 163             break;
 164
 165         case read_write:
 166             how = R_OK | W_OK;
 167             break;
 168     }
 169
 170     return wxAccess(name, how) == 0;
 171 }
 172
 173 // ----------------------------------------------------------------------------
 174 // opening/closing
 175 // ----------------------------------------------------------------------------
 176
 177 // ctors
 178 wxFile::wxFile(const wxString& fileName, OpenMode mode)
 179 {
 180     m_fd = fd_invalid;
 181     m_lasterror = 0;
 182
 183     Open(fileName, mode);
 184 }
 185
 186 bool wxFile::CheckForError(wxFileOffset rc) const
 187 {
 188     if ( rc != -1 )
 189         return false;
 190
 191     const_cast<wxFile *>(this)->m_lasterror =
 192 #ifndef __WXWINCE__
 193                                                 errno
 194 #else
 195                                                 ::GetLastError()
 196 #endif
 197                                                 ;
 198
 199     return true;
 200 }
 201
 202 // create the file, fail if it already exists and bOverwrite
 203 bool wxFile::Create(const wxString& fileName, bool bOverwrite, int accessMode)
 204 {
 205     // if bOverwrite we create a new file or truncate the existing one,
 206     // otherwise we only create the new file and fail if it already exists
 207     int fd = wxOpen( fileName,
 208                      O_BINARY | O_WRONLY | O_CREAT |
 209                      (bOverwrite ? O_TRUNC : O_EXCL),
 210                      accessMode );
 211     if ( CheckForError(fd) )
 212     {
 213         wxLogSysError(_("can't create file '%s'"), fileName);
 214         return false;
 215     }
 216
 217     Attach(fd);
 218     return true;
 219 }
 220
 221 // open the file
 222 bool wxFile::Open(const wxString& fileName, 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(fileName) )
 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 #ifdef __WINDOWS__
 255     // only read/write bits for "all" are supported by this function under
 256     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 257     // accessMode, so clear them as they have at best no effect anyhow
 258     accessMode &= wxS_IRUSR | wxS_IWUSR;
 259 #endif // __WINDOWS__
 260
 261     int fd = wxOpen( fileName, flags, accessMode);
 262
 263     if ( CheckForError(fd) )
 264     {
 265         wxLogSysError(_("can't open file '%s'"), fileName);
 266         return false;
 267     }
 268
 269     Attach(fd);
 270     return true;
 271 }
 272
 273 // close
 274 bool wxFile::Close()
 275 {
 276     if ( IsOpened() ) {
 277         if ( CheckForError(wxClose(m_fd)) )
 278         {
 279             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 280             m_fd = fd_invalid;
 281             return false;
 282         }
 283         else
 284             m_fd = fd_invalid;
 285     }
 286
 287     return true;
 288 }
 289
 290 // ----------------------------------------------------------------------------
 291 // read/write
 292 // ----------------------------------------------------------------------------
 293
 294 // read
 295 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 296 {
 297     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 298
 299     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 300
 301     if ( CheckForError(iRc) )
 302     {
 303         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 304         return wxInvalidOffset;
 305     }
 306
 307     return iRc;
 308 }
 309
 310 // write
 311 size_t wxFile::Write(const void *pBuf, size_t nCount)
 312 {
 313     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 314
 315     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 316
 317     if ( CheckForError(iRc) )
 318     {
 319         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 320         iRc = 0;
 321     }
 322
 323     return iRc;
 324 }
 325
 326 bool wxFile::Write(const wxString& s, const wxMBConv& conv)
 327 {
 328   const wxWX2MBbuf buf = s.mb_str(conv);
 329   if ( !buf )
 330       return false;
 331
 332 #if wxUSE_UNICODE
 333   const size_t size = buf.length();
 334 #else
 335   const size_t size = s.length();
 336 #endif
 337
 338   return Write(buf, size) == size;
 339 }
 340
 341 // flush
 342 bool wxFile::Flush()
 343 {
 344 #ifdef HAVE_FSYNC
 345     // fsync() only works on disk files and returns errors for pipes, don't
 346     // call it then
 347     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 348     {
 349         if ( CheckForError(wxFsync(m_fd)) )
 350         {
 351             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 352             return false;
 353         }
 354     }
 355 #endif // HAVE_FSYNC
 356
 357     return true;
 358 }
 359
 360 // ----------------------------------------------------------------------------
 361 // seek
 362 // ----------------------------------------------------------------------------
 363
 364 // seek
 365 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 366 {
 367     wxASSERT_MSG( IsOpened(), wxT("can't seek on closed file") );
 368     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 369                  wxInvalidOffset,
 370                  wxT("invalid absolute file offset") );
 371
 372     int origin;
 373     switch ( mode ) {
 374         default:
 375             wxFAIL_MSG(wxT("unknown seek origin"));
 376
 377         case wxFromStart:
 378             origin = SEEK_SET;
 379             break;
 380
 381         case wxFromCurrent:
 382             origin = SEEK_CUR;
 383             break;
 384
 385         case wxFromEnd:
 386             origin = SEEK_END;
 387             break;
 388     }
 389
 390     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 391     if ( CheckForError(iRc) )
 392     {
 393         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 394     }
 395
 396     return iRc;
 397 }
 398
 399 // get current file offset
 400 wxFileOffset wxFile::Tell() const
 401 {
 402     wxASSERT( IsOpened() );
 403
 404     wxFileOffset iRc = wxTell(m_fd);
 405     if ( CheckForError(iRc) )
 406     {
 407         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 408     }
 409
 410     return iRc;
 411 }
 412
 413 // get current file length
 414 wxFileOffset wxFile::Length() const
 415 {
 416     wxASSERT( IsOpened() );
 417
 418     // we use a special method for Linux systems where files in sysfs (i.e.
 419     // those under /sys typically) return length of 4096 bytes even when
 420     // they're much smaller -- this is a problem as it results in errors later
 421     // when we try reading 4KB from them
 422 #ifdef __LINUX__
 423     struct stat st;
 424     if ( fstat(m_fd, &st) == 0 )
 425     {
 426         // returning 0 for the special files indicates to the caller that they
 427         // are not seekable
 428         return st.st_blocks ? st.st_size : 0;
 429     }
 430     //else: failed to stat, try the normal method
 431 #endif // __LINUX__
 432
 433     wxFileOffset iRc = Tell();
 434     if ( iRc != wxInvalidOffset ) {
 435         wxFileOffset iLen = const_cast<wxFile *>(this)->SeekEnd();
 436         if ( iLen != wxInvalidOffset ) {
 437             // restore old position
 438             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 439                 // error
 440                 iLen = wxInvalidOffset;
 441             }
 442         }
 443
 444         iRc = iLen;
 445     }
 446
 447     if ( iRc == wxInvalidOffset )
 448     {
 449         // last error was already set by Tell()
 450         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 451     }
 452
 453     return iRc;
 454 }
 455
 456 // is end of file reached?
 457 bool wxFile::Eof() const
 458 {
 459     wxASSERT( IsOpened() );
 460
 461     wxFileOffset iRc;
 462
 463 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ )
 464     // @@ this doesn't work, of course, on unseekable file descriptors
 465     wxFileOffset ofsCur = Tell(),
 466     ofsMax = Length();
 467     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 468         iRc = wxInvalidOffset;
 469     else
 470         iRc = ofsCur == ofsMax;
 471 #else  // Windows and "native" compiler
 472     iRc = wxEof(m_fd);
 473 #endif // Windows/Unix
 474
 475     if ( iRc == 0 )
 476         return false;
 477
 478     if ( iRc == wxInvalidOffset )
 479     {
 480         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 481     }
 482     else if ( iRc != 1 )
 483     {
 484         wxFAIL_MSG(wxT("invalid eof() return value."));
 485     }
 486
 487     return true;
 488 }
 489
 490 // ============================================================================
 491 // implementation of wxTempFile
 492 // ============================================================================
 493
 494 // ----------------------------------------------------------------------------
 495 // construction
 496 // ----------------------------------------------------------------------------
 497
 498 wxTempFile::wxTempFile(const wxString& strName)
 499 {
 500     Open(strName);
 501 }
 502
 503 bool wxTempFile::Open(const wxString& strName)
 504 {
 505     // we must have an absolute filename because otherwise CreateTempFileName()
 506     // would create the temp file in $TMP (i.e. the system standard location
 507     // for the temp files) which might be on another volume/drive/mount and
 508     // wxRename()ing it later to m_strName from Commit() would then fail
 509     //
 510     // with the absolute filename, the temp file is created in the same
 511     // directory as this one which ensures that wxRename() may work later
 512     wxFileName fn(strName);
 513     if ( !fn.IsAbsolute() )
 514     {
 515         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 516     }
 517
 518     m_strName = fn.GetFullPath();
 519
 520     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 521
 522     if ( m_strTemp.empty() )
 523     {
 524         // CreateTempFileName() failed
 525         return false;
 526     }
 527
 528 #ifdef __UNIX__
 529     // the temp file should have the same permissions as the original one
 530     mode_t mode;
 531
 532     wxStructStat st;
 533     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 534     {
 535         mode = st.st_mode;
 536     }
 537     else
 538     {
 539         // file probably didn't exist, just give it the default mode _using_
 540         // user's umask (new files creation should respect umask)
 541         mode_t mask = umask(0777);
 542         mode = 0666 & ~mask;
 543         umask(mask);
 544     }
 545
 546     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 547     {
 548 #ifndef __OS2__
 549         wxLogSysError(_("Failed to set temporary file permissions"));
 550 #endif
 551     }
 552 #endif // Unix
 553
 554     return true;
 555 }
 556
 557 // ----------------------------------------------------------------------------
 558 // destruction
 559 // ----------------------------------------------------------------------------
 560
 561 wxTempFile::~wxTempFile()
 562 {
 563     if ( IsOpened() )
 564         Discard();
 565 }
 566
 567 bool wxTempFile::Commit()
 568 {
 569     m_file.Close();
 570
 571     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 572         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 573         return false;
 574     }
 575
 576     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 577         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 578         return false;
 579     }
 580
 581     return true;
 582 }
 583
 584 void wxTempFile::Discard()
 585 {
 586     m_file.Close();
 587     if ( wxRemove(m_strTemp) != 0 )
 588     {
 589         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 590     }
 591 }
 592
 593 #endif // wxUSE_FILE
 594