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 // Windows compilers don't have these constants
  90 #ifndef W_OK
  91     enum
  92     {
  93         F_OK = 0,   // test for existence
  94         X_OK = 1,   //          execute permission
  95         W_OK = 2,   //          write
  96         R_OK = 4    //          read
  97     };
  98 #endif // W_OK
  99
 100 // wxWidgets
 101 #ifndef WX_PRECOMP
 102     #include  "wx/string.h"
 103     #include  "wx/intl.h"
 104     #include  "wx/log.h"
 105     #include "wx/crt.h"
 106 #endif // !WX_PRECOMP
 107
 108 #include  "wx/filename.h"
 109 #include  "wx/file.h"
 110 #include  "wx/filefn.h"
 111
 112 // there is no distinction between text and binary files under Unix, so define
 113 // O_BINARY as 0 if the system headers don't do it already
 114 #if defined(__UNIX__) && !defined(O_BINARY)
 115     #define   O_BINARY    (0)
 116 #endif  //__UNIX__
 117
 118 #ifdef __WXMSW__
 119     #include "wx/msw/mslu.h"
 120 #endif
 121
 122 #ifdef __WXWINCE__
 123     #include "wx/msw/private.h"
 124 #endif
 125
 126 #ifndef MAX_PATH
 127     #define MAX_PATH 512
 128 #endif
 129
 130 // ============================================================================
 131 // implementation of wxFile
 132 // ============================================================================
 133
 134 // ----------------------------------------------------------------------------
 135 // static functions
 136 // ----------------------------------------------------------------------------
 137
 138 bool wxFile::Exists(const wxString& name)
 139 {
 140     return wxFileExists(name);
 141 }
 142
 143 bool wxFile::Access(const wxString& name, OpenMode mode)
 144 {
 145     int how;
 146
 147     switch ( mode )
 148     {
 149         default:
 150             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 151             // fall through
 152
 153         case read:
 154             how = R_OK;
 155             break;
 156
 157         case write:
 158             how = W_OK;
 159             break;
 160
 161         case read_write:
 162             how = R_OK | W_OK;
 163             break;
 164     }
 165
 166     return wxAccess(name, how) == 0;
 167 }
 168
 169 // ----------------------------------------------------------------------------
 170 // opening/closing
 171 // ----------------------------------------------------------------------------
 172
 173 // ctors
 174 wxFile::wxFile(const wxString& fileName, OpenMode mode)
 175 {
 176     m_fd = fd_invalid;
 177     m_error = false;
 178
 179     Open(fileName, mode);
 180 }
 181
 182 // create the file, fail if it already exists and bOverwrite
 183 bool wxFile::Create(const wxString& fileName, bool bOverwrite, int accessMode)
 184 {
 185     // if bOverwrite we create a new file or truncate the existing one,
 186     // otherwise we only create the new file and fail if it already exists
 187     int fd = wxOpen( fileName,
 188                      O_BINARY | O_WRONLY | O_CREAT |
 189                      (bOverwrite ? O_TRUNC : O_EXCL),
 190                      accessMode );
 191     if ( fd == -1 )
 192     {
 193         wxLogSysError(_("can't create file '%s'"), fileName);
 194         return false;
 195     }
 196
 197     Attach(fd);
 198     return true;
 199 }
 200
 201 // open the file
 202 bool wxFile::Open(const wxString& fileName, OpenMode mode, int accessMode)
 203 {
 204     int flags = O_BINARY;
 205
 206     switch ( mode )
 207     {
 208         case read:
 209             flags |= O_RDONLY;
 210             break;
 211
 212         case write_append:
 213             if ( wxFile::Exists(fileName) )
 214             {
 215                 flags |= O_WRONLY | O_APPEND;
 216                 break;
 217             }
 218             //else: fall through as write_append is the same as write if the
 219             //      file doesn't exist
 220
 221         case write:
 222             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 223             break;
 224
 225         case write_excl:
 226             flags |= O_WRONLY | O_CREAT | O_EXCL;
 227             break;
 228
 229         case read_write:
 230             flags |= O_RDWR;
 231             break;
 232     }
 233
 234 #ifdef __WINDOWS__
 235     // only read/write bits for "all" are supported by this function under
 236     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 237     // accessMode, so clear them as they have at best no effect anyhow
 238     accessMode &= wxS_IRUSR | wxS_IWUSR;
 239 #endif // __WINDOWS__
 240
 241     int fd = wxOpen( fileName, flags, accessMode);
 242
 243     if ( fd == -1 )
 244     {
 245         wxLogSysError(_("can't open file '%s'"), fileName);
 246         return false;
 247     }
 248
 249     Attach(fd);
 250     return true;
 251 }
 252
 253 // close
 254 bool wxFile::Close()
 255 {
 256     if ( IsOpened() ) {
 257         if (wxClose(m_fd) == -1)
 258         {
 259             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 260             m_fd = fd_invalid;
 261             return false;
 262         }
 263         else
 264             m_fd = fd_invalid;
 265     }
 266
 267     return true;
 268 }
 269
 270 // ----------------------------------------------------------------------------
 271 // read/write
 272 // ----------------------------------------------------------------------------
 273
 274 // read
 275 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 276 {
 277     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 278
 279     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 280
 281     if ( iRc == -1 )
 282     {
 283         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 284         return wxInvalidOffset;
 285     }
 286
 287     return iRc;
 288 }
 289
 290 // write
 291 size_t wxFile::Write(const void *pBuf, size_t nCount)
 292 {
 293     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 294
 295     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 296
 297     if ( iRc == -1 )
 298     {
 299         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 300         m_error = true;
 301         iRc = 0;
 302     }
 303
 304     return iRc;
 305 }
 306
 307 bool wxFile::Write(const wxString& s, const wxMBConv& conv)
 308 {
 309   const wxWX2MBbuf buf = s.mb_str(conv);
 310   if ( !buf )
 311       return false;
 312
 313   const size_t size = strlen(buf); // FIXME: use buf.length() when available
 314   return Write(buf, size) == size;
 315 }
 316
 317 // flush
 318 bool wxFile::Flush()
 319 {
 320 #ifdef HAVE_FSYNC
 321     // fsync() only works on disk files and returns errors for pipes, don't
 322     // call it then
 323     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 324     {
 325         if ( wxFsync(m_fd) == -1 )
 326         {
 327             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 328             return false;
 329         }
 330     }
 331 #endif // HAVE_FSYNC
 332
 333     return true;
 334 }
 335
 336 // ----------------------------------------------------------------------------
 337 // seek
 338 // ----------------------------------------------------------------------------
 339
 340 // seek
 341 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 342 {
 343     wxASSERT_MSG( IsOpened(), _T("can't seek on closed file") );
 344     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 345                  wxInvalidOffset,
 346                  _T("invalid absolute file offset") );
 347
 348     int origin;
 349     switch ( mode ) {
 350         default:
 351             wxFAIL_MSG(_T("unknown seek origin"));
 352
 353         case wxFromStart:
 354             origin = SEEK_SET;
 355             break;
 356
 357         case wxFromCurrent:
 358             origin = SEEK_CUR;
 359             break;
 360
 361         case wxFromEnd:
 362             origin = SEEK_END;
 363             break;
 364     }
 365
 366     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 367     if ( iRc == wxInvalidOffset )
 368     {
 369         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 370     }
 371
 372     return iRc;
 373 }
 374
 375 // get current file offset
 376 wxFileOffset wxFile::Tell() const
 377 {
 378     wxASSERT( IsOpened() );
 379
 380     wxFileOffset iRc = wxTell(m_fd);
 381     if ( iRc == wxInvalidOffset )
 382     {
 383         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 384     }
 385
 386     return iRc;
 387 }
 388
 389 // get current file length
 390 wxFileOffset wxFile::Length() const
 391 {
 392     wxASSERT( IsOpened() );
 393
 394     wxFileOffset iRc = Tell();
 395     if ( iRc != wxInvalidOffset ) {
 396         // have to use const_cast :-(
 397         wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
 398         if ( iLen != wxInvalidOffset ) {
 399             // restore old position
 400             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 401                 // error
 402                 iLen = wxInvalidOffset;
 403             }
 404         }
 405
 406         iRc = iLen;
 407     }
 408
 409     if ( iRc == wxInvalidOffset )
 410     {
 411         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 412     }
 413
 414     return iRc;
 415 }
 416
 417 // is end of file reached?
 418 bool wxFile::Eof() const
 419 {
 420     wxASSERT( IsOpened() );
 421
 422     wxFileOffset iRc;
 423
 424 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ )
 425     // @@ this doesn't work, of course, on unseekable file descriptors
 426     wxFileOffset ofsCur = Tell(),
 427     ofsMax = Length();
 428     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 429         iRc = wxInvalidOffset;
 430     else
 431         iRc = ofsCur == ofsMax;
 432 #else  // Windows and "native" compiler
 433     iRc = wxEof(m_fd);
 434 #endif // Windows/Unix
 435
 436     if ( iRc == 1)
 437         {}
 438     else if ( iRc == 0 )
 439         return false;
 440     else if ( iRc == wxInvalidOffset )
 441         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 442     else
 443         wxFAIL_MSG(_T("invalid eof() return value."));
 444
 445     return true;
 446 }
 447
 448 // ============================================================================
 449 // implementation of wxTempFile
 450 // ============================================================================
 451
 452 // ----------------------------------------------------------------------------
 453 // construction
 454 // ----------------------------------------------------------------------------
 455
 456 wxTempFile::wxTempFile(const wxString& strName)
 457 {
 458     Open(strName);
 459 }
 460
 461 bool wxTempFile::Open(const wxString& strName)
 462 {
 463     // we must have an absolute filename because otherwise CreateTempFileName()
 464     // would create the temp file in $TMP (i.e. the system standard location
 465     // for the temp files) which might be on another volume/drive/mount and
 466     // wxRename()ing it later to m_strName from Commit() would then fail
 467     //
 468     // with the absolute filename, the temp file is created in the same
 469     // directory as this one which ensures that wxRename() may work later
 470     wxFileName fn(strName);
 471     if ( !fn.IsAbsolute() )
 472     {
 473         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 474     }
 475
 476     m_strName = fn.GetFullPath();
 477
 478     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 479
 480     if ( m_strTemp.empty() )
 481     {
 482         // CreateTempFileName() failed
 483         return false;
 484     }
 485
 486 #ifdef __UNIX__
 487     // the temp file should have the same permissions as the original one
 488     mode_t mode;
 489
 490     wxStructStat st;
 491     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 492     {
 493         mode = st.st_mode;
 494     }
 495     else
 496     {
 497         // file probably didn't exist, just give it the default mode _using_
 498         // user's umask (new files creation should respect umask)
 499         mode_t mask = umask(0777);
 500         mode = 0666 & ~mask;
 501         umask(mask);
 502     }
 503
 504     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 505     {
 506 #ifndef __OS2__
 507         wxLogSysError(_("Failed to set temporary file permissions"));
 508 #endif
 509     }
 510 #endif // Unix
 511
 512     return true;
 513 }
 514
 515 // ----------------------------------------------------------------------------
 516 // destruction
 517 // ----------------------------------------------------------------------------
 518
 519 wxTempFile::~wxTempFile()
 520 {
 521     if ( IsOpened() )
 522         Discard();
 523 }
 524
 525 bool wxTempFile::Commit()
 526 {
 527     m_file.Close();
 528
 529     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 530         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 531         return false;
 532     }
 533
 534     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 535         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 536         return false;
 537     }
 538
 539     return true;
 540 }
 541
 542 void wxTempFile::Discard()
 543 {
 544     m_file.Close();
 545     if ( wxRemove(m_strTemp) != 0 )
 546         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 547 }
 548
 549 #endif // wxUSE_FILE
 550