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 // Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ----------------------------------------------------------------------------
  13 // headers
  14 // ----------------------------------------------------------------------------
  15
  16 // For compilers that support precompilation, includes "wx.h".
  17 #include "wx/wxprec.h"
  18
  19 #ifdef __BORLANDC__
  20   #pragma hdrstop
  21 #endif
  22
  23 #if wxUSE_FILE
  24
  25 // standard
  26 #if defined(__WINDOWS__) && !defined(__GNUWIN32__) && !defined(__WXMICROWIN__) && !defined(__WXWINCE__)
  27
  28 #define   WIN32_LEAN_AND_MEAN
  29 #define   NOSERVICE
  30 #define   NOIME
  31 #define   NOATOM
  32 #define   NOGDI
  33 #define   NOGDICAPMASKS
  34 #define   NOMETAFILE
  35 #define   NOMINMAX
  36 #define   NOMSG
  37 #define   NOOPENFILE
  38 #define   NORASTEROPS
  39 #define   NOSCROLL
  40 #define   NOSOUND
  41 #define   NOSYSMETRICS
  42 #define   NOTEXTMETRIC
  43 #define   NOWH
  44 #define   NOCOMM
  45 #define   NOKANJI
  46 #define   NOCRYPT
  47 #define   NOMCX
  48
  49 #elif defined(__WINDOWS__) && defined(__WXWINCE__)
  50     #include  "wx/msw/missing.h"
  51 #elif (defined(__OS2__))
  52     #include <io.h>
  53 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  54     #include  <unistd.h>
  55     #include  <time.h>
  56     #include  <sys/stat.h>
  57     #ifdef __GNUWIN32__
  58         #include "wx/msw/wrapwin.h"
  59     #endif
  60 #elif defined(__DOS__)
  61     #if defined(__WATCOMC__)
  62        #include <io.h>
  63     #elif defined(__DJGPP__)
  64        #include <io.h>
  65        #include <unistd.h>
  66        #include <stdio.h>
  67     #else
  68         #error  "Please specify the header with file functions declarations."
  69     #endif
  70 #elif (defined(__WXSTUBS__))
  71     // Have to ifdef this for different environments
  72     #include <io.h>
  73 #elif (defined(__WXMAC__))
  74 #if __MSL__ < 0x6000
  75     int access( const char *path, int mode ) { return 0 ; }
  76 #else
  77     int _access( const char *path, int mode ) { return 0 ; }
  78 #endif
  79     char* mktemp( char * path ) { return path ;}
  80     #include <stat.h>
  81     #include <unistd.h>
  82 #else
  83     #error  "Please specify the header with file functions declarations."
  84 #endif  //Win/UNIX
  85
  86 #include  <stdio.h>       // SEEK_xxx constants
  87
  88 #ifndef __WXWINCE__
  89     #include <errno.h>
  90 #endif
  91
  92 // Windows compilers don't have these constants
  93 #ifndef W_OK
  94     enum
  95     {
  96         F_OK = 0,   // test for existence
  97         X_OK = 1,   //          execute permission
  98         W_OK = 2,   //          write
  99         R_OK = 4    //          read
 100     };
 101 #endif // W_OK
 102
 103 // wxWidgets
 104 #ifndef WX_PRECOMP
 105     #include  "wx/string.h"
 106     #include  "wx/intl.h"
 107     #include  "wx/log.h"
 108     #include "wx/crt.h"
 109 #endif // !WX_PRECOMP
 110
 111 #include  "wx/filename.h"
 112 #include  "wx/file.h"
 113 #include  "wx/filefn.h"
 114
 115 // there is no distinction between text and binary files under Unix, so define
 116 // O_BINARY as 0 if the system headers don't do it already
 117 #if defined(__UNIX__) && !defined(O_BINARY)
 118     #define   O_BINARY    (0)
 119 #endif  //__UNIX__
 120
 121 #ifdef __WINDOWS__
 122     #include "wx/msw/mslu.h"
 123 #endif
 124
 125 #ifdef __WXWINCE__
 126     #include "wx/msw/private.h"
 127 #endif
 128
 129 #ifndef MAX_PATH
 130     #define MAX_PATH 512
 131 #endif
 132
 133 // ============================================================================
 134 // implementation of wxFile
 135 // ============================================================================
 136
 137 // ----------------------------------------------------------------------------
 138 // static functions
 139 // ----------------------------------------------------------------------------
 140
 141 bool wxFile::Exists(const wxString& name)
 142 {
 143     return wxFileExists(name);
 144 }
 145
 146 bool wxFile::Access(const wxString& name, OpenMode mode)
 147 {
 148     int how;
 149
 150     switch ( mode )
 151     {
 152         default:
 153             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 154             // fall through
 155
 156         case read:
 157             how = R_OK;
 158             break;
 159
 160         case write:
 161             how = W_OK;
 162             break;
 163
 164         case read_write:
 165             how = R_OK | W_OK;
 166             break;
 167     }
 168
 169     return wxAccess(name, how) == 0;
 170 }
 171
 172 // ----------------------------------------------------------------------------
 173 // opening/closing
 174 // ----------------------------------------------------------------------------
 175
 176 // ctors
 177 wxFile::wxFile(const wxString& fileName, OpenMode mode)
 178 {
 179     m_fd = fd_invalid;
 180     m_lasterror = 0;
 181
 182     Open(fileName, mode);
 183 }
 184
 185 bool wxFile::CheckForError(wxFileOffset rc) const
 186 {
 187     if ( rc != -1 )
 188         return false;
 189
 190     const_cast<wxFile *>(this)->m_lasterror =
 191 #ifndef __WXWINCE__
 192                                                 errno
 193 #else
 194                                                 ::GetLastError()
 195 #endif
 196                                                 ;
 197
 198     return true;
 199 }
 200
 201 // create the file, fail if it already exists and bOverwrite
 202 bool wxFile::Create(const wxString& fileName, bool bOverwrite, int accessMode)
 203 {
 204     // if bOverwrite we create a new file or truncate the existing one,
 205     // otherwise we only create the new file and fail if it already exists
 206     int fildes = wxOpen( fileName,
 207                      O_BINARY | O_WRONLY | O_CREAT |
 208                      (bOverwrite ? O_TRUNC : O_EXCL),
 209                      accessMode );
 210     if ( CheckForError(fildes) )
 211     {
 212         wxLogSysError(_("can't create file '%s'"), fileName);
 213         return false;
 214     }
 215
 216     Attach(fildes);
 217     return true;
 218 }
 219
 220 // open the file
 221 bool wxFile::Open(const wxString& fileName, 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(fileName) )
 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 fildes = wxOpen( fileName, flags, accessMode);
 261
 262     if ( CheckForError(fildes) )
 263     {
 264         wxLogSysError(_("can't open file '%s'"), fileName);
 265         return false;
 266     }
 267
 268     Attach(fildes);
 269     return true;
 270 }
 271
 272 // close
 273 bool wxFile::Close()
 274 {
 275     if ( IsOpened() ) {
 276         if ( CheckForError(wxClose(m_fd)) )
 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 bool wxFile::ReadAll(wxString *str, const wxMBConv& conv)
 294 {
 295     wxCHECK_MSG( str, false, wxS("Output string must be non-NULL") );
 296
 297     ssize_t length = Length();
 298     wxCHECK_MSG( (wxFileOffset)length == Length(), false, wxT("huge file not supported") );
 299
 300     wxCharBuffer buf(length);
 301     char* p = buf.data();
 302     for ( ;; )
 303     {
 304         static const ssize_t READSIZE = 4096;
 305
 306         ssize_t nread = Read(p, length > READSIZE ? READSIZE : length);
 307         if ( nread == wxInvalidOffset )
 308             return false;
 309
 310         p += nread;
 311         if ( length <= nread )
 312             break;
 313
 314         length -= nread;
 315     }
 316
 317     *p = 0;
 318
 319     wxString strTmp(buf, conv);
 320     str->swap(strTmp);
 321
 322     return true;
 323 }
 324
 325 // read
 326 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 327 {
 328     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 329
 330     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 331
 332     if ( CheckForError(iRc) )
 333     {
 334         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 335         return wxInvalidOffset;
 336     }
 337
 338     return iRc;
 339 }
 340
 341 // write
 342 size_t wxFile::Write(const void *pBuf, size_t nCount)
 343 {
 344     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 345
 346     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 347
 348     if ( CheckForError(iRc) )
 349     {
 350         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 351         iRc = 0;
 352     }
 353
 354     return iRc;
 355 }
 356
 357 bool wxFile::Write(const wxString& s, const wxMBConv& conv)
 358 {
 359   const wxWX2MBbuf buf = s.mb_str(conv);
 360   if ( !buf )
 361       return false;
 362
 363 #if wxUSE_UNICODE
 364   const size_t size = buf.length();
 365 #else
 366   const size_t size = s.length();
 367 #endif
 368
 369   return Write(buf, size) == size;
 370 }
 371
 372 // flush
 373 bool wxFile::Flush()
 374 {
 375 #ifdef HAVE_FSYNC
 376     // fsync() only works on disk files and returns errors for pipes, don't
 377     // call it then
 378     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 379     {
 380         if ( CheckForError(wxFsync(m_fd)) )
 381         {
 382             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 383             return false;
 384         }
 385     }
 386 #endif // HAVE_FSYNC
 387
 388     return true;
 389 }
 390
 391 // ----------------------------------------------------------------------------
 392 // seek
 393 // ----------------------------------------------------------------------------
 394
 395 // seek
 396 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 397 {
 398     wxASSERT_MSG( IsOpened(), wxT("can't seek on closed file") );
 399     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 400                  wxInvalidOffset,
 401                  wxT("invalid absolute file offset") );
 402
 403     int origin;
 404     switch ( mode ) {
 405         default:
 406             wxFAIL_MSG(wxT("unknown seek origin"));
 407
 408         case wxFromStart:
 409             origin = SEEK_SET;
 410             break;
 411
 412         case wxFromCurrent:
 413             origin = SEEK_CUR;
 414             break;
 415
 416         case wxFromEnd:
 417             origin = SEEK_END;
 418             break;
 419     }
 420
 421     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 422     if ( CheckForError(iRc) )
 423     {
 424         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 425     }
 426
 427     return iRc;
 428 }
 429
 430 // get current file offset
 431 wxFileOffset wxFile::Tell() const
 432 {
 433     wxASSERT( IsOpened() );
 434
 435     wxFileOffset iRc = wxTell(m_fd);
 436     if ( CheckForError(iRc) )
 437     {
 438         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 439     }
 440
 441     return iRc;
 442 }
 443
 444 // get current file length
 445 wxFileOffset wxFile::Length() const
 446 {
 447     wxASSERT( IsOpened() );
 448
 449     // we use a special method for Linux systems where files in sysfs (i.e.
 450     // those under /sys typically) return length of 4096 bytes even when
 451     // they're much smaller -- this is a problem as it results in errors later
 452     // when we try reading 4KB from them
 453 #ifdef __LINUX__
 454     struct stat st;
 455     if ( fstat(m_fd, &st) == 0 )
 456     {
 457         // returning 0 for the special files indicates to the caller that they
 458         // are not seekable
 459         return st.st_blocks ? st.st_size : 0;
 460     }
 461     //else: failed to stat, try the normal method
 462 #endif // __LINUX__
 463
 464     wxFileOffset iRc = Tell();
 465     if ( iRc != wxInvalidOffset ) {
 466         wxFileOffset iLen = const_cast<wxFile *>(this)->SeekEnd();
 467         if ( iLen != wxInvalidOffset ) {
 468             // restore old position
 469             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 470                 // error
 471                 iLen = wxInvalidOffset;
 472             }
 473         }
 474
 475         iRc = iLen;
 476     }
 477
 478     if ( iRc == wxInvalidOffset )
 479     {
 480         // last error was already set by Tell()
 481         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 482     }
 483
 484     return iRc;
 485 }
 486
 487 // is end of file reached?
 488 bool wxFile::Eof() const
 489 {
 490     wxASSERT( IsOpened() );
 491
 492     wxFileOffset iRc;
 493
 494 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__)
 495     // @@ this doesn't work, of course, on unseekable file descriptors
 496     wxFileOffset ofsCur = Tell(),
 497     ofsMax = Length();
 498     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 499         iRc = wxInvalidOffset;
 500     else
 501         iRc = ofsCur == ofsMax;
 502 #else  // Windows and "native" compiler
 503     iRc = wxEof(m_fd);
 504 #endif // Windows/Unix
 505
 506     if ( iRc == 0 )
 507         return false;
 508
 509     if ( iRc == wxInvalidOffset )
 510     {
 511         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 512     }
 513
 514     return true;
 515 }
 516
 517 // ============================================================================
 518 // implementation of wxTempFile
 519 // ============================================================================
 520
 521 // ----------------------------------------------------------------------------
 522 // construction
 523 // ----------------------------------------------------------------------------
 524
 525 wxTempFile::wxTempFile(const wxString& strName)
 526 {
 527     Open(strName);
 528 }
 529
 530 bool wxTempFile::Open(const wxString& strName)
 531 {
 532     // we must have an absolute filename because otherwise CreateTempFileName()
 533     // would create the temp file in $TMP (i.e. the system standard location
 534     // for the temp files) which might be on another volume/drive/mount and
 535     // wxRename()ing it later to m_strName from Commit() would then fail
 536     //
 537     // with the absolute filename, the temp file is created in the same
 538     // directory as this one which ensures that wxRename() may work later
 539     wxFileName fn(strName);
 540     if ( !fn.IsAbsolute() )
 541     {
 542         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 543     }
 544
 545     m_strName = fn.GetFullPath();
 546
 547     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 548
 549     if ( m_strTemp.empty() )
 550     {
 551         // CreateTempFileName() failed
 552         return false;
 553     }
 554
 555 #ifdef __UNIX__
 556     // the temp file should have the same permissions as the original one
 557     mode_t mode;
 558
 559     wxStructStat st;
 560     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 561     {
 562         mode = st.st_mode;
 563     }
 564     else
 565     {
 566         // file probably didn't exist, just give it the default mode _using_
 567         // user's umask (new files creation should respect umask)
 568         mode_t mask = umask(0777);
 569         mode = 0666 & ~mask;
 570         umask(mask);
 571     }
 572
 573     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 574     {
 575 #ifndef __OS2__
 576         wxLogSysError(_("Failed to set temporary file permissions"));
 577 #endif
 578     }
 579 #endif // Unix
 580
 581     return true;
 582 }
 583
 584 // ----------------------------------------------------------------------------
 585 // destruction
 586 // ----------------------------------------------------------------------------
 587
 588 wxTempFile::~wxTempFile()
 589 {
 590     if ( IsOpened() )
 591         Discard();
 592 }
 593
 594 bool wxTempFile::Commit()
 595 {
 596     m_file.Close();
 597
 598     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 599         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 600         return false;
 601     }
 602
 603     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 604         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 605         return false;
 606     }
 607
 608     return true;
 609 }
 610
 611 void wxTempFile::Discard()
 612 {
 613     m_file.Close();
 614     if ( wxRemove(m_strTemp) != 0 )
 615     {
 616         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 617     }
 618 }
 619
 620 #endif // wxUSE_FILE
 621