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
  91   #define   S_IREAD     _S_IREAD
  92   #define   S_IWRITE    _S_IWRITE
  93 #else
  94   #define   tell(fd)    lseek(fd, 0, SEEK_CUR)
  95 #endif  //_MSC_VER
  96
  97 // there is no distinction between text and binary files under Unix
  98 #ifdef          __UNIX__
  99         #define         O_BINARY                (0)
 100 #endif  //__UNIX__
 101
 102 // wxWindows
 103 #include  <wx/string.h>
 104 #include  <wx/intl.h>
 105 #include  <wx/file.h>
 106 #include  <wx/log.h>
 107
 108
 109 // ============================================================================
 110 // implementation of wxFile
 111 // ============================================================================
 112
 113 // ----------------------------------------------------------------------------
 114 // static functions
 115 // ----------------------------------------------------------------------------
 116 bool wxFile::Exists(const char *sz)
 117 {
 118   struct stat st;
 119   return !access(sz, 0) && !stat(sz, &st) && (st.st_mode & S_IFREG);
 120 }
 121
 122 // ----------------------------------------------------------------------------
 123 // opening/closing
 124 // ----------------------------------------------------------------------------
 125
 126 // ctors
 127 wxFile::wxFile(const char *szFileName, OpenMode mode)
 128 {
 129   m_fd = fd_invalid;
 130   m_error = FALSE;
 131
 132   Open(szFileName, mode);
 133 }
 134
 135 // dtor
 136 wxFile::~wxFile()
 137 {
 138   Close();
 139 }
 140
 141 // create the file, fail if it already exists and bOverwrite
 142 bool wxFile::Create(const char *szFileName, bool bOverwrite)
 143 {
 144   // if bOverwrite we create a new file or truncate the existing one,
 145   // otherwise we only create the new file and fail if it already exists
 146   int fd = open(szFileName, O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL));
 147
 148   if ( fd == -1 ) {
 149     wxLogSysError("can't create file '%s'", szFileName);
 150     return FALSE;
 151   }
 152   else {
 153     Attach(fd);
 154     return TRUE;
 155   }
 156 }
 157
 158 // open the file
 159 bool wxFile::Open(const char *szFileName, OpenMode mode)
 160 {
 161   int flags = O_BINARY;
 162
 163   switch ( mode ) {
 164     case read:
 165       flags |= O_RDONLY;
 166       break;
 167
 168     case write:
 169       flags |= O_WRONLY | O_CREAT | O_TRUNC;
 170       break;
 171
 172     case write_append:
 173       flags |= O_WRONLY | O_APPEND;
 174       break;
 175
 176     case read_write:
 177       flags |= O_RDWR;
 178       break;
 179   }
 180
 181   int fd = open(szFileName, flags, S_IREAD | S_IWRITE);
 182
 183   if ( fd == -1 ) {
 184     wxLogSysError("can't open file '%s'", szFileName);
 185     return FALSE;
 186   }
 187   else {
 188     Attach(fd);
 189     return TRUE;
 190   }
 191 }
 192
 193 // close
 194 bool wxFile::Close()
 195 {
 196   if ( IsOpened() ) {
 197     if ( close(m_fd) == -1 ) {
 198       wxLogSysError("can't close file descriptor %d", m_fd);
 199       m_fd = fd_invalid;
 200       return FALSE;
 201     }
 202     else
 203       m_fd = fd_invalid;
 204   }
 205
 206   return TRUE;
 207 }
 208
 209 // ----------------------------------------------------------------------------
 210 // read/write
 211 // ----------------------------------------------------------------------------
 212
 213 // read
 214 off_t wxFile::Read(void *pBuf, off_t nCount)
 215 {
 216   wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 217
 218   int iRc = ::read(m_fd, pBuf, nCount);
 219   if ( iRc == -1 ) {
 220     wxLogSysError("can't read from file descriptor %d", m_fd);
 221     return ofsInvalid;
 222   }
 223   else
 224     return (uint)iRc;
 225 }
 226
 227 // write
 228 uint wxFile::Write(const void *pBuf, uint nCount)
 229 {
 230   wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
 231
 232   int iRc = ::write(m_fd, pBuf, nCount);
 233   if ( iRc == -1 ) {
 234     wxLogSysError("can't write to file descriptor %d", m_fd);
 235     m_error = TRUE;
 236     return 0;
 237   }
 238   else
 239     return iRc;
 240 }
 241
 242 // flush
 243 bool wxFile::Flush()
 244 {
 245   if ( IsOpened() ) {
 246                 // @@@ fsync() is not ANSI (BSDish)
 247 //    if ( fsync(m_fd) == -1 ) { // TODO
 248       if (TRUE) {
 249       wxLogSysError("can't flush file descriptor %d", m_fd);
 250       return FALSE;
 251     }
 252   }
 253
 254   return TRUE;
 255 }
 256
 257 // ----------------------------------------------------------------------------
 258 // seek
 259 // ----------------------------------------------------------------------------
 260
 261 // seek
 262 off_t wxFile::Seek(off_t ofs, wxSeekMode mode)
 263 {
 264   wxASSERT( IsOpened() );
 265
 266   int flag = -1;
 267   switch ( mode ) {
 268     case wxFromStart:
 269       flag = SEEK_SET;
 270       break;
 271
 272     case wxFromCurrent:
 273       flag = SEEK_CUR;
 274       break;
 275
 276     case wxFromEnd:
 277       flag = SEEK_END;
 278       break;
 279
 280     default:
 281       wxFAIL_MSG("unknown seek origin");
 282   }
 283
 284   int iRc = lseek(m_fd, ofs, flag);
 285   if ( iRc == -1 ) {
 286     wxLogSysError("can't seek on file descriptor %d", m_fd);
 287     return ofsInvalid;
 288   }
 289   else
 290     return (off_t)iRc;
 291 }
 292
 293 // get current off_t
 294 off_t wxFile::Tell() const
 295 {
 296   wxASSERT( IsOpened() );
 297
 298   int iRc = tell(m_fd);
 299   if ( iRc == -1 ) {
 300     wxLogSysError("can't get seek position on file descriptor %d", m_fd);
 301     return ofsInvalid;
 302   }
 303   else
 304     return (off_t)iRc;
 305 }
 306
 307 // get current file length
 308 off_t wxFile::Length() const
 309 {
 310   wxASSERT( IsOpened() );
 311
 312   #ifdef  _MSC_VER
 313     int iRc = _filelength(m_fd);
 314   #else
 315     int iRc = tell(m_fd);
 316     if ( iRc != -1 ) {
 317                         // @ have to use const_cast :-(
 318       int iLen = ((wxFile *)this)->SeekEnd();
 319       if ( iLen != -1 ) {
 320         // restore old position
 321         if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 322           // error
 323           iLen = -1;
 324         }
 325       }
 326
 327       iRc = iLen;
 328     }
 329
 330   #endif  //_MSC_VER
 331
 332   if ( iRc == -1 ) {
 333     wxLogSysError("can't find length of file on file descriptor %d", m_fd);
 334     return ofsInvalid;
 335   }
 336   else
 337     return (off_t)iRc;
 338 }
 339
 340 // is end of file reached?
 341 bool wxFile::Eof() const
 342 {
 343   wxASSERT( IsOpened() );
 344
 345   int iRc;
 346
 347   #if defined(__UNIX__) || defined(__GNUWIN32__)
 348     // @@ this doesn't work, of course, on unseekable file descriptors
 349     off_t ofsCur = Tell(),
 350           ofsMax = Length();
 351     if ( ofsCur == ofsInvalid || ofsMax == ofsInvalid )
 352       iRc = -1;
 353     else
 354      iRc = ofsCur == ofsMax;
 355   #else  // Windows and "native" compiler
 356     iRc = eof(m_fd);
 357   #endif // Windows/Unix
 358
 359   switch ( iRc ) {
 360     case 1:
 361       break;
 362
 363     case 0:
 364       return FALSE;
 365
 366     case -1:
 367       wxLogSysError("can't determine if the end of file is reached on "
 368                     "descriptor %d", m_fd);
 369       break;
 370
 371     default:
 372       wxFAIL_MSG("invalid eof() return value.");
 373   }
 374
 375   return TRUE;
 376 }
 377
 378 // ============================================================================
 379 // implementation of wxTempFile
 380 // ============================================================================
 381
 382 // ----------------------------------------------------------------------------
 383 // construction
 384 // ----------------------------------------------------------------------------
 385 wxTempFile::wxTempFile(const wxString& strName)
 386 {
 387   Open(strName);
 388 }
 389
 390 bool wxTempFile::Open(const wxString& strName)
 391 {
 392   m_strName = strName;
 393
 394   // we want to create the file in the same directory as strName because
 395   // otherwise rename() in Commit() might not work (if the files are on
 396   // different partitions for example). Unfortunately, the only standard
 397   // (POSIX) temp file creation function tmpnam() can't do it.
 398   #ifdef  __UNIX__
 399     static const char *szMktempSuffix = "XXXXXX";
 400     m_strTemp << strName << szMktempSuffix;
 401     mktemp((char *)m_strTemp.c_str()); // will do because length doesn't change
 402   #else // Windows
 403     wxString strPath;
 404     wxSplitPath(strName, &strPath, NULL, NULL);
 405     if ( strPath.IsEmpty() )
 406       strPath = '.';  // GetTempFileName will fail if we give it empty string
 407     if ( !GetTempFileName(strPath, "wx_",0, m_strTemp.GetWriteBuf(MAX_PATH)) )
 408       wxLogLastError("GetTempFileName");
 409     m_strTemp.UngetWriteBuf();
 410   #endif  // Windows/Unix
 411
 412   return m_file.Open(m_strTemp, wxFile::write);
 413 }
 414
 415 // ----------------------------------------------------------------------------
 416 // destruction
 417 // ----------------------------------------------------------------------------
 418
 419 wxTempFile::~wxTempFile()
 420 {
 421   if ( IsOpened() )
 422     Discard();
 423 }
 424
 425 bool wxTempFile::Commit()
 426 {
 427   m_file.Close();
 428
 429   if ( wxFile::Exists(m_strName) && remove(m_strName) != 0 ) {
 430     wxLogSysError("can't remove file '%s'", m_strName.c_str());
 431     return FALSE;
 432   }
 433
 434   if ( rename(m_strTemp, m_strName) != 0 ) {
 435     wxLogSysError("can't commit changes to file '%s'", m_strName.c_str());
 436     return FALSE;
 437   }
 438
 439   return TRUE;
 440 }
 441
 442 void wxTempFile::Discard()
 443 {
 444   m_file.Close();
 445   if ( remove(m_strTemp) != 0 )
 446     wxLogSysError("can't remove temporary file '%s'", m_strTemp.c_str());
 447 }