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 #elif defined(__WXPALMOS__)
  84     #include "wx/palmos/missing.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 // wxWidgets
 103 #ifndef WX_PRECOMP
 104     #include  "wx/string.h"
 105     #include  "wx/intl.h"
 106     #include  "wx/log.h"
 107     #include "wx/crt.h"
 108 #endif // !WX_PRECOMP
 109
 110 #include  "wx/filename.h"
 111 #include  "wx/file.h"
 112 #include  "wx/filefn.h"
 113
 114 // there is no distinction between text and binary files under Unix, so define
 115 // O_BINARY as 0 if the system headers don't do it already
 116 #if defined(__UNIX__) && !defined(O_BINARY)
 117     #define   O_BINARY    (0)
 118 #endif  //__UNIX__
 119
 120 #ifdef __WXMSW__
 121     #include "wx/msw/mslu.h"
 122 #endif
 123
 124 #ifdef __WXWINCE__
 125     #include "wx/msw/private.h"
 126 #endif
 127
 128 #ifndef MAX_PATH
 129     #define MAX_PATH 512
 130 #endif
 131
 132 // ============================================================================
 133 // implementation of wxFile
 134 // ============================================================================
 135
 136 // ----------------------------------------------------------------------------
 137 // static functions
 138 // ----------------------------------------------------------------------------
 139
 140 bool wxFile::Exists(const wxString& name)
 141 {
 142     return wxFileExists(name);
 143 }
 144
 145 bool wxFile::Access(const wxString& name, OpenMode mode)
 146 {
 147     int how;
 148
 149     switch ( mode )
 150     {
 151         default:
 152             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 153             // fall through
 154
 155         case read:
 156             how = R_OK;
 157             break;
 158
 159         case write:
 160             how = W_OK;
 161             break;
 162
 163         case read_write:
 164             how = R_OK | W_OK;
 165             break;
 166     }
 167
 168     return wxAccess(name, how) == 0;
 169 }
 170
 171 // ----------------------------------------------------------------------------
 172 // opening/closing
 173 // ----------------------------------------------------------------------------
 174
 175 // ctors
 176 wxFile::wxFile(const wxString& fileName, OpenMode mode)
 177 {
 178     m_fd = fd_invalid;
 179     m_error = false;
 180
 181     Open(fileName, mode);
 182 }
 183
 184 // create the file, fail if it already exists and bOverwrite
 185 bool wxFile::Create(const wxString& fileName, bool bOverwrite, int accessMode)
 186 {
 187     // if bOverwrite we create a new file or truncate the existing one,
 188     // otherwise we only create the new file and fail if it already exists
 189     int fd = wxOpen( fileName,
 190                      O_BINARY | O_WRONLY | O_CREAT |
 191                      (bOverwrite ? O_TRUNC : O_EXCL),
 192                      accessMode );
 193     if ( fd == -1 )
 194     {
 195         wxLogSysError(_("can't create file '%s'"), fileName);
 196         return false;
 197     }
 198
 199     Attach(fd);
 200     return true;
 201 }
 202
 203 // open the file
 204 bool wxFile::Open(const wxString& fileName, OpenMode mode, int accessMode)
 205 {
 206     int flags = O_BINARY;
 207
 208     switch ( mode )
 209     {
 210         case read:
 211             flags |= O_RDONLY;
 212             break;
 213
 214         case write_append:
 215             if ( wxFile::Exists(fileName) )
 216             {
 217                 flags |= O_WRONLY | O_APPEND;
 218                 break;
 219             }
 220             //else: fall through as write_append is the same as write if the
 221             //      file doesn't exist
 222
 223         case write:
 224             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 225             break;
 226
 227         case write_excl:
 228             flags |= O_WRONLY | O_CREAT | O_EXCL;
 229             break;
 230
 231         case read_write:
 232             flags |= O_RDWR;
 233             break;
 234     }
 235
 236 #ifdef __WINDOWS__
 237     // only read/write bits for "all" are supported by this function under
 238     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 239     // accessMode, so clear them as they have at best no effect anyhow
 240     accessMode &= wxS_IRUSR | wxS_IWUSR;
 241 #endif // __WINDOWS__
 242
 243     int fd = wxOpen( fileName, flags, accessMode);
 244
 245     if ( fd == -1 )
 246     {
 247         wxLogSysError(_("can't open file '%s'"), fileName);
 248         return false;
 249     }
 250
 251     Attach(fd);
 252     return true;
 253 }
 254
 255 // close
 256 bool wxFile::Close()
 257 {
 258     if ( IsOpened() ) {
 259         if (wxClose(m_fd) == -1)
 260         {
 261             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 262             m_fd = fd_invalid;
 263             return false;
 264         }
 265         else
 266             m_fd = fd_invalid;
 267     }
 268
 269     return true;
 270 }
 271
 272 // ----------------------------------------------------------------------------
 273 // read/write
 274 // ----------------------------------------------------------------------------
 275
 276 // read
 277 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 278 {
 279     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 280
 281     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 282
 283     if ( iRc == -1 )
 284     {
 285         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 286         return wxInvalidOffset;
 287     }
 288
 289     return iRc;
 290 }
 291
 292 // write
 293 size_t wxFile::Write(const void *pBuf, size_t nCount)
 294 {
 295     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 296
 297     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 298
 299     if ( iRc == -1 )
 300     {
 301         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 302         m_error = true;
 303         iRc = 0;
 304     }
 305
 306     return iRc;
 307 }
 308
 309 bool wxFile::Write(const wxString& s, const wxMBConv& conv)
 310 {
 311   const wxWX2MBbuf buf = s.mb_str(conv);
 312   if ( !buf )
 313       return false;
 314
 315   const size_t size = strlen(buf); // FIXME: use buf.length() when available
 316   return Write(buf, size) == size;
 317 }
 318
 319 // flush
 320 bool wxFile::Flush()
 321 {
 322 #ifdef HAVE_FSYNC
 323     // fsync() only works on disk files and returns errors for pipes, don't
 324     // call it then
 325     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 326     {
 327         if ( wxFsync(m_fd) == -1 )
 328         {
 329             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 330             return false;
 331         }
 332     }
 333 #endif // HAVE_FSYNC
 334
 335     return true;
 336 }
 337
 338 // ----------------------------------------------------------------------------
 339 // seek
 340 // ----------------------------------------------------------------------------
 341
 342 // seek
 343 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 344 {
 345     wxASSERT_MSG( IsOpened(), wxT("can't seek on closed file") );
 346     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 347                  wxInvalidOffset,
 348                  wxT("invalid absolute file offset") );
 349
 350     int origin;
 351     switch ( mode ) {
 352         default:
 353             wxFAIL_MSG(wxT("unknown seek origin"));
 354
 355         case wxFromStart:
 356             origin = SEEK_SET;
 357             break;
 358
 359         case wxFromCurrent:
 360             origin = SEEK_CUR;
 361             break;
 362
 363         case wxFromEnd:
 364             origin = SEEK_END;
 365             break;
 366     }
 367
 368     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 369     if ( iRc == wxInvalidOffset )
 370     {
 371         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 372     }
 373
 374     return iRc;
 375 }
 376
 377 // get current file offset
 378 wxFileOffset wxFile::Tell() const
 379 {
 380     wxASSERT( IsOpened() );
 381
 382     wxFileOffset iRc = wxTell(m_fd);
 383     if ( iRc == wxInvalidOffset )
 384     {
 385         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 386     }
 387
 388     return iRc;
 389 }
 390
 391 // get current file length
 392 wxFileOffset wxFile::Length() const
 393 {
 394     wxASSERT( IsOpened() );
 395
 396     // we use a special method for Linux systems where files in sysfs (i.e.
 397     // those under /sys typically) return length of 4096 bytes even when
 398     // they're much smaller -- this is a problem as it results in errors later
 399     // when we try reading 4KB from them
 400 #ifdef __LINUX__
 401     struct stat st;
 402     if ( fstat(m_fd, &st) == 0 )
 403     {
 404         // returning 0 for the special files indicates to the caller that they
 405         // are not seekable
 406         return st.st_blocks ? st.st_size : 0;
 407     }
 408     //else: failed to stat, try the normal method
 409 #endif // __LINUX__
 410
 411     wxFileOffset iRc = Tell();
 412     if ( iRc != wxInvalidOffset ) {
 413         // have to use const_cast :-(
 414         wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
 415         if ( iLen != wxInvalidOffset ) {
 416             // restore old position
 417             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 418                 // error
 419                 iLen = wxInvalidOffset;
 420             }
 421         }
 422
 423         iRc = iLen;
 424     }
 425
 426     if ( iRc == wxInvalidOffset )
 427     {
 428         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 429     }
 430
 431     return iRc;
 432 }
 433
 434 // is end of file reached?
 435 bool wxFile::Eof() const
 436 {
 437     wxASSERT( IsOpened() );
 438
 439     wxFileOffset iRc;
 440
 441 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ )
 442     // @@ this doesn't work, of course, on unseekable file descriptors
 443     wxFileOffset ofsCur = Tell(),
 444     ofsMax = Length();
 445     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 446         iRc = wxInvalidOffset;
 447     else
 448         iRc = ofsCur == ofsMax;
 449 #else  // Windows and "native" compiler
 450     iRc = wxEof(m_fd);
 451 #endif // Windows/Unix
 452
 453     if ( iRc == 0 )
 454         return false;
 455
 456     if ( iRc == wxInvalidOffset )
 457     {
 458         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 459     }
 460     else if ( iRc != 1 )
 461     {
 462         wxFAIL_MSG(wxT("invalid eof() return value."));
 463     }
 464
 465     return true;
 466 }
 467
 468 // ============================================================================
 469 // implementation of wxTempFile
 470 // ============================================================================
 471
 472 // ----------------------------------------------------------------------------
 473 // construction
 474 // ----------------------------------------------------------------------------
 475
 476 wxTempFile::wxTempFile(const wxString& strName)
 477 {
 478     Open(strName);
 479 }
 480
 481 bool wxTempFile::Open(const wxString& strName)
 482 {
 483     // we must have an absolute filename because otherwise CreateTempFileName()
 484     // would create the temp file in $TMP (i.e. the system standard location
 485     // for the temp files) which might be on another volume/drive/mount and
 486     // wxRename()ing it later to m_strName from Commit() would then fail
 487     //
 488     // with the absolute filename, the temp file is created in the same
 489     // directory as this one which ensures that wxRename() may work later
 490     wxFileName fn(strName);
 491     if ( !fn.IsAbsolute() )
 492     {
 493         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 494     }
 495
 496     m_strName = fn.GetFullPath();
 497
 498     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 499
 500     if ( m_strTemp.empty() )
 501     {
 502         // CreateTempFileName() failed
 503         return false;
 504     }
 505
 506 #ifdef __UNIX__
 507     // the temp file should have the same permissions as the original one
 508     mode_t mode;
 509
 510     wxStructStat st;
 511     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 512     {
 513         mode = st.st_mode;
 514     }
 515     else
 516     {
 517         // file probably didn't exist, just give it the default mode _using_
 518         // user's umask (new files creation should respect umask)
 519         mode_t mask = umask(0777);
 520         mode = 0666 & ~mask;
 521         umask(mask);
 522     }
 523
 524     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 525     {
 526 #ifndef __OS2__
 527         wxLogSysError(_("Failed to set temporary file permissions"));
 528 #endif
 529     }
 530 #endif // Unix
 531
 532     return true;
 533 }
 534
 535 // ----------------------------------------------------------------------------
 536 // destruction
 537 // ----------------------------------------------------------------------------
 538
 539 wxTempFile::~wxTempFile()
 540 {
 541     if ( IsOpened() )
 542         Discard();
 543 }
 544
 545 bool wxTempFile::Commit()
 546 {
 547     m_file.Close();
 548
 549     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 550         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 551         return false;
 552     }
 553
 554     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 555         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 556         return false;
 557     }
 558
 559     return true;
 560 }
 561
 562 void wxTempFile::Discard()
 563 {
 564     m_file.Close();
 565     if ( wxRemove(m_strTemp) != 0 )
 566     {
 567         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 568     }
 569 }
 570
 571 #endif // wxUSE_FILE
 572