src/common/file.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        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 license
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 // ----------------------------------------------------------------------------
  14 // headers
  15 // ----------------------------------------------------------------------------
  16
  17 #ifdef __GNUG__
  18 #pragma implementation "file.h"
  19 #endif
  20
  21 // For compilers that support precompilation, includes "wx.h".
  22 #include "wx/wxprec.h"
  23 #include "wx/defs.h"
  24
  25 #ifdef __BORLANDC__
  26 #pragma hdrstop
  27 #endif
  28
  29 // standard
  30 #if   defined(__WXMSW__) && !defined(__GNUWIN32__)
  31   #include  <io.h>
  32
  33   #define   WIN32_LEAN_AND_MEAN
  34   #define   NOSERVICE
  35   #define   NOIME
  36   #define   NOATOM
  37   #define   NOGDI
  38   #define   NOGDICAPMASKS
  39   #define   NOMETAFILE
  40   #define   NOMINMAX
  41   #define   NOMSG
  42   #define   NOOPENFILE
  43   #define   NORASTEROPS
  44   #define   NOSCROLL
  45   #define   NOSOUND
  46   #define   NOSYSMETRICS
  47   #define   NOTEXTMETRIC
  48   #define   NOWH
  49   #define   NOCOMM
  50   #define   NOKANJI
  51   #define   NOCRYPT
  52   #define   NOMCX
  53   #include  <windows.h>     // for GetTempFileName
  54 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  55   #include  <unistd.h>
  56 #else
  57   #error  "Please specify the header with file functions declarations."
  58 #endif  //Win/UNIX
  59
  60 #include  <stdio.h>       // SEEK_xxx constants
  61 #include  <fcntl.h>       // O_RDONLY &c
  62 #include  <sys/types.h>   // needed for stat
  63 #include  <sys/stat.h>    // stat
  64
  65 // Microsoft compiler loves underscores, feed them to it
  66 #ifdef    _MSC_VER
  67   // functions
  68   #define   open        _open
  69   #define   close       _close
  70   #define   read        _read
  71   #define   write       _write
  72   #define   lseek       _lseek
  73   #define   fsync       _commit
  74   #define   access      _access
  75   #define   eof         _eof
  76
  77   // types
  78   #define   stat        _stat
  79
  80   // constants
  81   #define   O_RDONLY    _O_RDONLY
  82   #define   O_WRONLY    _O_WRONLY
  83   #define   O_RDWR      _O_RDWR
  84   #define   O_EXCL      _O_EXCL
  85   #define   O_CREAT     _O_CREAT
  86   #define   O_BINARY    _O_BINARY
  87
  88   #define   S_IFDIR     _S_IFDIR
  89   #define   S_IFREG     _S_IFREG
  90 #else
  91   #define   tell(fd)    lseek(fd, 0, SEEK_CUR)
  92 #endif  //_MSC_VER
  93
  94 // there is no distinction between text and binary files under Unix
  95 #ifdef    __UNIX__
  96   #define   O_BINARY    (0)
  97 #endif  //__UNIX__
  98
  99 // wxWindows
 100 #include  <wx/string.h>
 101 #include  <wx/intl.h>
 102 #include  <wx/file.h>
 103 #include  <wx/log.h>
 104
 105
 106 // ============================================================================
 107 // implementation of wxFile
 108 // ============================================================================
 109
 110 // ----------------------------------------------------------------------------
 111 // static functions
 112 // ----------------------------------------------------------------------------
 113 bool wxFile::Exists(const char *sz)
 114 {
 115   struct stat st;
 116   return !access(sz, 0) && !stat(sz, &st) && (st.st_mode & S_IFREG);
 117 }
 118
 119 // ----------------------------------------------------------------------------
 120 // opening/closing
 121 // ----------------------------------------------------------------------------
 122
 123 // ctors
 124 wxFile::wxFile(const char *szFileName, OpenMode mode)
 125 {
 126   m_fd = fd_invalid;
 127   m_error = FALSE;
 128
 129   Open(szFileName, mode);
 130 }
 131
 132 // dtor
 133 wxFile::~wxFile()
 134 {
 135   Close();
 136 }
 137
 138 // create the file, fail if it already exists and bOverwrite
 139 bool wxFile::Create(const char *szFileName, bool bOverwrite, int access)
 140 {
 141   // if bOverwrite we create a new file or truncate the existing one,
 142   // otherwise we only create the new file and fail if it already exists
 143   int fd = open(szFileName, O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
 144
 145   if ( fd == -1 ) {
 146     wxLogSysError(_("can't create file '%s'"), szFileName);
 147     return FALSE;
 148   }
 149   else {
 150     Attach(fd);
 151     return TRUE;
 152   }
 153 }
 154
 155 // open the file
 156 bool wxFile::Open(const char *szFileName, OpenMode mode, int access)
 157 {
 158   int flags = O_BINARY;
 159
 160   switch ( mode ) {
 161     case read:
 162       flags |= O_RDONLY;
 163       break;
 164
 165     case write:
 166       flags |= O_WRONLY | O_CREAT | O_TRUNC;
 167       break;
 168
 169     case write_append:
 170       flags |= O_WRONLY | O_APPEND;
 171       break;
 172
 173     case read_write:
 174       flags |= O_RDWR;
 175       break;
 176   }
 177
 178   int fd = open(szFileName, flags, access);
 179
 180   if ( fd == -1 ) {
 181     wxLogSysError(_("can't open file '%s'"), szFileName);
 182     return FALSE;
 183   }
 184   else {
 185     Attach(fd);
 186     return TRUE;
 187   }
 188 }
 189
 190 // close
 191 bool wxFile::Close()
 192 {
 193   if ( IsOpened() ) {
 194     if ( close(m_fd) == -1 ) {
 195       wxLogSysError(_("can't close file descriptor %d"), m_fd);
 196       m_fd = fd_invalid;
 197       return FALSE;
 198     }
 199     else
 200       m_fd = fd_invalid;
 201   }
 202
 203   return TRUE;
 204 }
 205
 206 // ----------------------------------------------------------------------------
 207 // read/write
 208 // ----------------------------------------------------------------------------
 209
 210 // read
 211 off_t wxFile::Read(void *pBuf, off_t nCount)
 212 {
 213   wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 214
 215   int iRc = ::read(m_fd, pBuf, nCount);
 216   if ( iRc == -1 ) {
 217     wxLogSysError(_("can't read from file descriptor %d"), m_fd);
 218     return ofsInvalid;
 219   }
 220   else
 221     return (uint)iRc;
 222 }
 223
 224 // write
 225 uint wxFile::Write(const void *pBuf, uint nCount)
 226 {
 227   wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 228
 229   int iRc = ::write(m_fd, pBuf, nCount);
 230   if ( iRc == -1 ) {
 231     wxLogSysError(_("can't write to file descriptor %d"), m_fd);
 232     m_error = TRUE;
 233     return 0;
 234   }
 235   else
 236     return (uint)iRc;
 237 }
 238
 239 // flush
 240 bool wxFile::Flush()
 241 {
 242   if ( IsOpened() ) {
 243 // @@@ fsync() is not ANSI (BSDish)
 244 //    if ( fsync(m_fd) == -1 ) { // TODO
 245       if (TRUE) {
 246       wxLogSysError(_("can't flush file descriptor %d"), m_fd);
 247       return FALSE;
 248     }
 249   }
 250
 251   return TRUE;
 252 }
 253
 254 // ----------------------------------------------------------------------------
 255 // seek
 256 // ----------------------------------------------------------------------------
 257
 258 // seek
 259 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 260 {
 261   wxASSERT( IsOpened() );
 262
 263   int flag = -1;
 264   switch ( mode ) {
 265     case wxFromStart:
 266       flag = SEEK_SET;
 267       break;
 268
 269     case wxFromCurrent:
 270       flag = SEEK_CUR;
 271       break;
 272
 273     case wxFromEnd:
 274       flag = SEEK_END;
 275       break;
 276
 277     default:
 278       wxFAIL_MSG("unknown seek origin");
 279   }
 280
 281   int iRc = lseek(m_fd, ofs, flag);
 282   if ( iRc == -1 ) {
 283     wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
 284     return ofsInvalid;
 285   }
 286   else
 287     return (off_t)iRc;
 288 }
 289
 290 // get current off_t
 291 off_t wxFile::Tell() const
 292 {
 293   wxASSERT( IsOpened() );
 294
 295   int iRc = tell(m_fd);
 296   if ( iRc == -1 ) {
 297     wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
 298     return ofsInvalid;
 299   }
 300   else
 301     return (off_t)iRc;
 302 }
 303
 304 // get current file length
 305 off_t wxFile::Length() const
 306 {
 307   wxASSERT( IsOpened() );
 308
 309   #ifdef  _MSC_VER
 310     int iRc = _filelength(m_fd);
 311   #else
 312     int iRc = tell(m_fd);
 313     if ( iRc != -1 ) {
 314       // @ have to use const_cast :-(
 315       int iLen = ((wxFile *)this)->SeekEnd();
 316       if ( iLen != -1 ) {
 317         // restore old position
 318         if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 319           // error
 320           iLen = -1;
 321         }
 322       }
 323
 324       iRc = iLen;
 325     }
 326
 327   #endif  //_MSC_VER
 328
 329   if ( iRc == -1 ) {
 330     wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
 331     return ofsInvalid;
 332   }
 333   else
 334     return (off_t)iRc;
 335 }
 336
 337 // is end of file reached?
 338 bool wxFile::Eof() const
 339 {
 340   wxASSERT( IsOpened() );
 341
 342   int iRc;
 343
 344   #if defined(__UNIX__) || defined(__GNUWIN32__)
 345     // @@ this doesn't work, of course, on unseekable file descriptors
 346     off_t ofsCur = Tell(),
 347           ofsMax = Length();
 348     if ( ofsCur == ofsInvalid || ofsMax == ofsInvalid )
 349       iRc = -1;
 350     else
 351      iRc = ofsCur == ofsMax;
 352   #else  // Windows and "native" compiler
 353     iRc = eof(m_fd);
 354   #endif // Windows/Unix
 355
 356   switch ( iRc ) {
 357     case 1:
 358       break;
 359
 360     case 0:
 361       return FALSE;
 362
 363     case -1:
 364       wxLogSysError(_("can't determine if the end of file is reached on "
 365                       "descriptor %d"), m_fd);
 366       break;
 367
 368     default:
 369       wxFAIL_MSG("invalid eof() return value.");
 370   }
 371
 372   return TRUE;
 373 }
 374
 375 // ============================================================================
 376 // implementation of wxTempFile
 377 // ============================================================================
 378
 379 // ----------------------------------------------------------------------------
 380 // construction
 381 // ----------------------------------------------------------------------------
 382 wxTempFile::wxTempFile(const wxString& strName)
 383 {
 384   Open(strName);
 385 }
 386
 387 bool wxTempFile::Open(const wxString& strName)
 388 {
 389   m_strName = strName;
 390
 391   // we want to create the file in the same directory as strName because
 392   // otherwise rename() in Commit() might not work (if the files are on
 393   // different partitions for example). Unfortunately, the only standard
 394   // (POSIX) temp file creation function tmpnam() can't do it.
 395   #ifdef  __UNIX__
 396     static const char *szMktempSuffix = "XXXXXX";
 397     m_strTemp << strName << szMktempSuffix;
 398     mktemp((char *)m_strTemp.c_str()); // will do because length doesn't change
 399   #else // Windows
 400     wxString strPath;
 401     wxSplitPath(strName, &strPath, NULL, NULL);
 402     if ( strPath.IsEmpty() )
 403       strPath = '.';  // GetTempFileName will fail if we give it empty string
 404     if ( !GetTempFileName(strPath, "wx_",0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 405       wxLogLastError("GetTempFileName");
 406     m_strTemp.UngetWriteBuf();
 407   #endif  // Windows/Unix
 408
 409   return m_file.Open(m_strTemp, wxFile::write);
 410 }
 411
 412 // ----------------------------------------------------------------------------
 413 // destruction
 414 // ----------------------------------------------------------------------------
 415
 416 wxTempFile::~wxTempFile()
 417 {
 418   if ( IsOpened() )
 419     Discard();
 420 }
 421
 422 bool wxTempFile::Commit()
 423 {
 424   m_file.Close();
 425
 426   if ( wxFile::Exists(m_strName) && remove(m_strName) != 0 ) {
 427     wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
 428     return FALSE;
 429   }
 430
 431   if ( rename(m_strTemp, m_strName) != 0 ) {
 432     wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
 433     return FALSE;
 434   }
 435
 436   return TRUE;
 437 }
 438
 439 void wxTempFile::Discard()
 440 {
 441   m_file.Close();
 442   if ( remove(m_strTemp) != 0 )
 443     wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
 444 }