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 #ifndef __WXWINCE__
  92     #include <errno.h>
  93 #endif
  94
  95 // Windows compilers don't have these constants
  96 #ifndef W_OK
  97     enum
  98     {
  99         F_OK = 0,   // test for existence
 100         X_OK = 1,   //          execute permission
 101         W_OK = 2,   //          write
 102         R_OK = 4    //          read
 103     };
 104 #endif // W_OK
 105
 106 // wxWidgets
 107 #ifndef WX_PRECOMP
 108     #include  "wx/string.h"
 109     #include  "wx/intl.h"
 110     #include  "wx/log.h"
 111     #include "wx/crt.h"
 112 #endif // !WX_PRECOMP
 113
 114 #include  "wx/filename.h"
 115 #include  "wx/file.h"
 116 #include  "wx/filefn.h"
 117
 118 // there is no distinction between text and binary files under Unix, so define
 119 // O_BINARY as 0 if the system headers don't do it already
 120 #if defined(__UNIX__) && !defined(O_BINARY)
 121     #define   O_BINARY    (0)
 122 #endif  //__UNIX__
 123
 124 #ifdef __WXMSW__
 125     #include "wx/msw/mslu.h"
 126 #endif
 127
 128 #ifdef __WXWINCE__
 129     #include "wx/msw/private.h"
 130 #endif
 131
 132 #ifndef MAX_PATH
 133     #define MAX_PATH 512
 134 #endif
 135
 136 // ============================================================================
 137 // implementation of wxFile
 138 // ============================================================================
 139
 140 // ----------------------------------------------------------------------------
 141 // static functions
 142 // ----------------------------------------------------------------------------
 143
 144 bool wxFile::Exists(const wxString& name)
 145 {
 146     return wxFileExists(name);
 147 }
 148
 149 bool wxFile::Access(const wxString& name, OpenMode mode)
 150 {
 151     int how;
 152
 153     switch ( mode )
 154     {
 155         default:
 156             wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
 157             // fall through
 158
 159         case read:
 160             how = R_OK;
 161             break;
 162
 163         case write:
 164             how = W_OK;
 165             break;
 166
 167         case read_write:
 168             how = R_OK | W_OK;
 169             break;
 170     }
 171
 172     return wxAccess(name, how) == 0;
 173 }
 174
 175 // ----------------------------------------------------------------------------
 176 // opening/closing
 177 // ----------------------------------------------------------------------------
 178
 179 // ctors
 180 wxFile::wxFile(const wxString& fileName, OpenMode mode)
 181 {
 182     m_fd = fd_invalid;
 183     m_lasterror = 0;
 184
 185     Open(fileName, mode);
 186 }
 187
 188 bool wxFile::CheckForError(wxFileOffset rc) const
 189 {
 190     if ( rc != -1 )
 191         return false;
 192
 193     const_cast<wxFile *>(this)->m_lasterror =
 194 #ifndef __WXWINCE__
 195                                                 errno
 196 #else
 197                                                 ::GetLastError()
 198 #endif
 199                                                 ;
 200
 201     return true;
 202 }
 203
 204 // create the file, fail if it already exists and bOverwrite
 205 bool wxFile::Create(const wxString& fileName, bool bOverwrite, int accessMode)
 206 {
 207     // if bOverwrite we create a new file or truncate the existing one,
 208     // otherwise we only create the new file and fail if it already exists
 209     int fd = wxOpen( fileName,
 210                      O_BINARY | O_WRONLY | O_CREAT |
 211                      (bOverwrite ? O_TRUNC : O_EXCL),
 212                      accessMode );
 213     if ( CheckForError(fd) )
 214     {
 215         wxLogSysError(_("can't create file '%s'"), fileName);
 216         return false;
 217     }
 218
 219     Attach(fd);
 220     return true;
 221 }
 222
 223 // open the file
 224 bool wxFile::Open(const wxString& fileName, OpenMode mode, int accessMode)
 225 {
 226     int flags = O_BINARY;
 227
 228     switch ( mode )
 229     {
 230         case read:
 231             flags |= O_RDONLY;
 232             break;
 233
 234         case write_append:
 235             if ( wxFile::Exists(fileName) )
 236             {
 237                 flags |= O_WRONLY | O_APPEND;
 238                 break;
 239             }
 240             //else: fall through as write_append is the same as write if the
 241             //      file doesn't exist
 242
 243         case write:
 244             flags |= O_WRONLY | O_CREAT | O_TRUNC;
 245             break;
 246
 247         case write_excl:
 248             flags |= O_WRONLY | O_CREAT | O_EXCL;
 249             break;
 250
 251         case read_write:
 252             flags |= O_RDWR;
 253             break;
 254     }
 255
 256 #ifdef __WINDOWS__
 257     // only read/write bits for "all" are supported by this function under
 258     // Windows, and VC++ 8 returns EINVAL if any other bits are used in
 259     // accessMode, so clear them as they have at best no effect anyhow
 260     accessMode &= wxS_IRUSR | wxS_IWUSR;
 261 #endif // __WINDOWS__
 262
 263     int fd = wxOpen( fileName, flags, accessMode);
 264
 265     if ( CheckForError(fd) )
 266     {
 267         wxLogSysError(_("can't open file '%s'"), fileName);
 268         return false;
 269     }
 270
 271     Attach(fd);
 272     return true;
 273 }
 274
 275 // close
 276 bool wxFile::Close()
 277 {
 278     if ( IsOpened() ) {
 279         if ( CheckForError(wxClose(m_fd)) )
 280         {
 281             wxLogSysError(_("can't close file descriptor %d"), m_fd);
 282             m_fd = fd_invalid;
 283             return false;
 284         }
 285         else
 286             m_fd = fd_invalid;
 287     }
 288
 289     return true;
 290 }
 291
 292 // ----------------------------------------------------------------------------
 293 // read/write
 294 // ----------------------------------------------------------------------------
 295
 296 // read
 297 ssize_t wxFile::Read(void *pBuf, size_t nCount)
 298 {
 299     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 300
 301     ssize_t iRc = wxRead(m_fd, pBuf, nCount);
 302
 303     if ( CheckForError(iRc) )
 304     {
 305         wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 306         return wxInvalidOffset;
 307     }
 308
 309     return iRc;
 310 }
 311
 312 // write
 313 size_t wxFile::Write(const void *pBuf, size_t nCount)
 314 {
 315     wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 316
 317     ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
 318
 319     if ( CheckForError(iRc) )
 320     {
 321         wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 322         iRc = 0;
 323     }
 324
 325     return iRc;
 326 }
 327
 328 bool wxFile::Write(const wxString& s, const wxMBConv& conv)
 329 {
 330   const wxWX2MBbuf buf = s.mb_str(conv);
 331   if ( !buf )
 332       return false;
 333
 334 #if wxUSE_UNICODE
 335   const size_t size = buf.length();
 336 #else
 337   const size_t size = s.length();
 338 #endif
 339
 340   return Write(buf, size) == size;
 341 }
 342
 343 // flush
 344 bool wxFile::Flush()
 345 {
 346 #ifdef HAVE_FSYNC
 347     // fsync() only works on disk files and returns errors for pipes, don't
 348     // call it then
 349     if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
 350     {
 351         if ( CheckForError(wxFsync(m_fd)) )
 352         {
 353             wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 354             return false;
 355         }
 356     }
 357 #endif // HAVE_FSYNC
 358
 359     return true;
 360 }
 361
 362 // ----------------------------------------------------------------------------
 363 // seek
 364 // ----------------------------------------------------------------------------
 365
 366 // seek
 367 wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
 368 {
 369     wxASSERT_MSG( IsOpened(), wxT("can't seek on closed file") );
 370     wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
 371                  wxInvalidOffset,
 372                  wxT("invalid absolute file offset") );
 373
 374     int origin;
 375     switch ( mode ) {
 376         default:
 377             wxFAIL_MSG(wxT("unknown seek origin"));
 378
 379         case wxFromStart:
 380             origin = SEEK_SET;
 381             break;
 382
 383         case wxFromCurrent:
 384             origin = SEEK_CUR;
 385             break;
 386
 387         case wxFromEnd:
 388             origin = SEEK_END;
 389             break;
 390     }
 391
 392     wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
 393     if ( CheckForError(iRc) )
 394     {
 395         wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 396     }
 397
 398     return iRc;
 399 }
 400
 401 // get current file offset
 402 wxFileOffset wxFile::Tell() const
 403 {
 404     wxASSERT( IsOpened() );
 405
 406     wxFileOffset iRc = wxTell(m_fd);
 407     if ( CheckForError(iRc) )
 408     {
 409         wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 410     }
 411
 412     return iRc;
 413 }
 414
 415 // get current file length
 416 wxFileOffset wxFile::Length() const
 417 {
 418     wxASSERT( IsOpened() );
 419
 420     // we use a special method for Linux systems where files in sysfs (i.e.
 421     // those under /sys typically) return length of 4096 bytes even when
 422     // they're much smaller -- this is a problem as it results in errors later
 423     // when we try reading 4KB from them
 424 #ifdef __LINUX__
 425     struct stat st;
 426     if ( fstat(m_fd, &st) == 0 )
 427     {
 428         // returning 0 for the special files indicates to the caller that they
 429         // are not seekable
 430         return st.st_blocks ? st.st_size : 0;
 431     }
 432     //else: failed to stat, try the normal method
 433 #endif // __LINUX__
 434
 435     wxFileOffset iRc = Tell();
 436     if ( iRc != wxInvalidOffset ) {
 437         wxFileOffset iLen = const_cast<wxFile *>(this)->SeekEnd();
 438         if ( iLen != wxInvalidOffset ) {
 439             // restore old position
 440             if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
 441                 // error
 442                 iLen = wxInvalidOffset;
 443             }
 444         }
 445
 446         iRc = iLen;
 447     }
 448
 449     if ( iRc == wxInvalidOffset )
 450     {
 451         // last error was already set by Tell()
 452         wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 453     }
 454
 455     return iRc;
 456 }
 457
 458 // is end of file reached?
 459 bool wxFile::Eof() const
 460 {
 461     wxASSERT( IsOpened() );
 462
 463     wxFileOffset iRc;
 464
 465 #if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ )
 466     // @@ this doesn't work, of course, on unseekable file descriptors
 467     wxFileOffset ofsCur = Tell(),
 468     ofsMax = Length();
 469     if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
 470         iRc = wxInvalidOffset;
 471     else
 472         iRc = ofsCur == ofsMax;
 473 #else  // Windows and "native" compiler
 474     iRc = wxEof(m_fd);
 475 #endif // Windows/Unix
 476
 477     if ( iRc == 0 )
 478         return false;
 479
 480     if ( iRc == wxInvalidOffset )
 481     {
 482         wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
 483     }
 484     else if ( iRc != 1 )
 485     {
 486         wxFAIL_MSG(wxT("invalid eof() return value."));
 487     }
 488
 489     return true;
 490 }
 491
 492 // ============================================================================
 493 // implementation of wxTempFile
 494 // ============================================================================
 495
 496 // ----------------------------------------------------------------------------
 497 // construction
 498 // ----------------------------------------------------------------------------
 499
 500 wxTempFile::wxTempFile(const wxString& strName)
 501 {
 502     Open(strName);
 503 }
 504
 505 bool wxTempFile::Open(const wxString& strName)
 506 {
 507     // we must have an absolute filename because otherwise CreateTempFileName()
 508     // would create the temp file in $TMP (i.e. the system standard location
 509     // for the temp files) which might be on another volume/drive/mount and
 510     // wxRename()ing it later to m_strName from Commit() would then fail
 511     //
 512     // with the absolute filename, the temp file is created in the same
 513     // directory as this one which ensures that wxRename() may work later
 514     wxFileName fn(strName);
 515     if ( !fn.IsAbsolute() )
 516     {
 517         fn.Normalize(wxPATH_NORM_ABSOLUTE);
 518     }
 519
 520     m_strName = fn.GetFullPath();
 521
 522     m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
 523
 524     if ( m_strTemp.empty() )
 525     {
 526         // CreateTempFileName() failed
 527         return false;
 528     }
 529
 530 #ifdef __UNIX__
 531     // the temp file should have the same permissions as the original one
 532     mode_t mode;
 533
 534     wxStructStat st;
 535     if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
 536     {
 537         mode = st.st_mode;
 538     }
 539     else
 540     {
 541         // file probably didn't exist, just give it the default mode _using_
 542         // user's umask (new files creation should respect umask)
 543         mode_t mask = umask(0777);
 544         mode = 0666 & ~mask;
 545         umask(mask);
 546     }
 547
 548     if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
 549     {
 550 #ifndef __OS2__
 551         wxLogSysError(_("Failed to set temporary file permissions"));
 552 #endif
 553     }
 554 #endif // Unix
 555
 556     return true;
 557 }
 558
 559 // ----------------------------------------------------------------------------
 560 // destruction
 561 // ----------------------------------------------------------------------------
 562
 563 wxTempFile::~wxTempFile()
 564 {
 565     if ( IsOpened() )
 566         Discard();
 567 }
 568
 569 bool wxTempFile::Commit()
 570 {
 571     m_file.Close();
 572
 573     if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
 574         wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 575         return false;
 576     }
 577
 578     if ( !wxRenameFile(m_strTemp, m_strName)  ) {
 579         wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 580         return false;
 581     }
 582
 583     return true;
 584 }
 585
 586 void wxTempFile::Discard()
 587 {
 588     m_file.Close();
 589     if ( wxRemove(m_strTemp) != 0 )
 590     {
 591         wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 592     }
 593 }
 594
 595 #endif // wxUSE_FILE
 596