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(__WINDOWS__) && !defined(__GNUWIN32__)
  31   #include  <io.h>
  32 #elif (defined(__UNIX__) || defined(__GNUWIN32__))
  33   #include  <unistd.h>
  34 #else
  35         #error  "Please specify the header with file functions declarations."
  36 #endif  //Win/UNIX
  37
  38 #include  <stdio.h>       // SEEK_xxx constants
  39 #include  <fcntl.h>       // O_RDONLY &c
  40 #include  <sys/types.h>   // needed for stat
  41 #include  <sys/stat.h>    // stat
  42
  43 // Microsoft compiler loves underscores, feed them to it
  44 #ifdef    _MSC_VER
  45   // functions
  46   #define   open        _open
  47   #define   close       _close
  48   #define   read        _read
  49   #define   write       _write
  50   #define   lseek       _lseek
  51   #define   fsync       _commit
  52   #define   access      _access
  53   #define   eof         _eof
  54
  55   // types
  56   #define   stat        _stat
  57
  58   // constants
  59   #define   O_RDONLY    _O_RDONLY
  60   #define   O_WRONLY    _O_WRONLY
  61   #define   O_RDWR      _O_RDWR
  62   #define   O_EXCL      _O_EXCL
  63   #define   O_CREAT     _O_CREAT
  64   #define   O_BINARY    _O_BINARY
  65
  66   #define   S_IFDIR     _S_IFDIR
  67   #define   S_IFREG     _S_IFREG
  68
  69   #define   S_IREAD     _S_IREAD
  70   #define   S_IWRITE    _S_IWRITE
  71 #else
  72   #define   tell(fd)    lseek(fd, 0, SEEK_CUR)
  73 #endif  //_MSC_VER
  74
  75 // there is no distinction between text and binary files under Unix
  76 #ifdef          __UNIX__
  77         #define         O_BINARY                (0)
  78 #endif  //__UNIX__
  79
  80 // wxWindows
  81 #include  <wx/string.h>
  82 #include  <wx/intl.h>
  83 #include  <wx/file.h>
  84 #include  <wx/log.h>
  85
  86
  87 // ============================================================================
  88 // implementation of wxFile
  89 // ============================================================================
  90
  91 // ----------------------------------------------------------------------------
  92 // static functions
  93 // ----------------------------------------------------------------------------
  94 bool wxFile::Exists(const char *sz)
  95 {
  96   struct stat st;
  97   return !access(sz, 0) && !stat(sz, &st) && (st.st_mode & S_IFREG);
  98 }
  99
 100 // ----------------------------------------------------------------------------
 101 // opening/closing
 102 // ----------------------------------------------------------------------------
 103
 104 // ctors
 105 wxFile::wxFile(const char *szFileName, OpenMode mode)
 106 {
 107   m_fd = fd_invalid;
 108
 109   Open(szFileName, mode);
 110 }
 111
 112 // dtor
 113 wxFile::~wxFile()
 114 {
 115   Close();
 116 }
 117
 118 // create the file, fail if it already exists and bOverwrite
 119 bool wxFile::Create(const char *szFileName, bool bOverwrite)
 120 {
 121   // if bOverwrite we create a new file or truncate the existing one,
 122   // otherwise we only create the new file and fail if it already exists
 123   int fd = bOverwrite ? creat(szFileName, 0)
 124                       : open(szFileName, O_CREAT | O_EXCL);
 125
 126   if ( fd == -1 ) {
 127     wxLogSysError("can't create file '%s'", szFileName);
 128     return FALSE;
 129   }
 130   else {
 131     Attach(fd);
 132     return TRUE;
 133   }
 134 }
 135
 136 // open the file
 137 bool wxFile::Open(const char *szFileName, OpenMode mode)
 138 {
 139   int flags = O_BINARY;
 140
 141   switch ( mode ) {
 142     case read:
 143       flags |= O_RDONLY;
 144       break;
 145
 146     case write:
 147       flags |= O_WRONLY | O_CREAT;
 148       break;
 149
 150     case read_write:
 151       flags |= O_RDWR;
 152       break;
 153   }
 154
 155   int fd = open(szFileName, flags, S_IREAD | S_IWRITE);
 156
 157   if ( fd == -1 ) {
 158     wxLogSysError("can't open file '%s'", szFileName);
 159     return FALSE;
 160   }
 161   else {
 162     Attach(fd);
 163     return TRUE;
 164   }
 165 }
 166
 167 // close
 168 void wxFile::Close()
 169 {
 170   if ( IsOpened() ) {
 171     if ( close(m_fd) == -1 )
 172       wxLogSysError("can't close file descriptor %d", m_fd);
 173
 174     m_fd = fd_invalid;
 175   }
 176 }
 177
 178 // ----------------------------------------------------------------------------
 179 // read/write
 180 // ----------------------------------------------------------------------------
 181
 182 // read
 183 off_t wxFile::Read(void *pBuf, off_t nCount)
 184 {
 185   wxCHECK_RET( (pBuf != NULL) && IsOpened(), 0 );
 186
 187   int iRc = ::read(m_fd, pBuf, nCount);
 188   if ( iRc == -1 ) {
 189     wxLogSysError("can't read from file descriptor %d", m_fd);
 190     return ofsInvalid;
 191   }
 192   else
 193     return (uint)iRc;
 194 }
 195
 196 // write
 197 bool wxFile::Write(const void *pBuf, uint nCount)
 198 {
 199   wxCHECK_RET( (pBuf != NULL) && IsOpened(), 0 );
 200
 201   int iRc = ::write(m_fd, pBuf, nCount);
 202   if ( iRc == -1 ) {
 203     wxLogSysError("can't write to file descriptor %d", m_fd);
 204     return FALSE;
 205   }
 206   else
 207     return TRUE;
 208 }
 209
 210 // flush
 211 bool wxFile::Flush()
 212 {
 213   if ( IsOpened() ) {
 214                 // ## fsync() is not ANSI (BSDish)
 215 //    if ( fsync(m_fd) == -1 ) { // TODO
 216       if (TRUE) {
 217       wxLogSysError("can't flush file descriptor %d", m_fd);
 218       return FALSE;
 219     }
 220   }
 221
 222   return TRUE;
 223 }
 224
 225 // ----------------------------------------------------------------------------
 226 // seek
 227 // ----------------------------------------------------------------------------
 228
 229 // seek
 230 off_t wxFile::Seek(off_t ofs, SeekMode mode)
 231 {
 232   wxASSERT( IsOpened() );
 233
 234   int flag = -1;
 235   switch ( mode ) {
 236     case FromStart:
 237       flag = SEEK_SET;
 238       break;
 239
 240     case FromCurrent:
 241       flag = SEEK_CUR;
 242       break;
 243
 244     case FromEnd:
 245       flag = SEEK_END;
 246       break;
 247
 248     default:
 249       wxFAIL_MSG("unknown seek origin");
 250   }
 251
 252   int iRc = lseek(m_fd, ofs, flag);
 253   if ( iRc == -1 ) {
 254     wxLogSysError("can't seek on file descriptor %d", m_fd);
 255     return ofsInvalid;
 256   }
 257   else
 258     return (off_t)iRc;
 259 }
 260
 261 // get current off_t
 262 off_t wxFile::Tell() const
 263 {
 264   wxASSERT( IsOpened() );
 265
 266   int iRc = tell(m_fd);
 267   if ( iRc == -1 ) {
 268     wxLogSysError("can't get seek position on file descriptor %d", m_fd);
 269     return ofsInvalid;
 270   }
 271   else
 272     return (off_t)iRc;
 273 }
 274
 275 // get current file length
 276 off_t wxFile::Length() const
 277 {
 278   wxASSERT( IsOpened() );
 279
 280   #ifdef  _MSC_VER
 281     int iRc = _filelength(m_fd);
 282   #else
 283     int iRc = tell(m_fd);
 284     if ( iRc != -1 ) {
 285                         // # have to use const_cast :-(
 286       int iLen = ((wxFile *)this)->SeekEnd();
 287       if ( iLen != -1 ) {
 288         // restore old position
 289         if ( ((wxFile *)this)->Seek(iRc) == -1 ) {
 290           // error
 291           iLen = -1;
 292         }
 293       }
 294
 295       iRc = iLen;
 296     }
 297
 298   #endif  //_MSC_VER
 299
 300   if ( iRc == -1 ) {
 301     wxLogSysError("can't find length of file on file descriptor %d", m_fd);
 302     return ofsInvalid;
 303   }
 304   else
 305     return (off_t)iRc;
 306 }
 307
 308 // is end of file reached?
 309 bool wxFile::Eof() const
 310 {
 311   wxASSERT( IsOpened() );
 312
 313   // TODO: no eof in GnuWin32
 314
 315 #ifdef __LINUX__
 316
 317   int iRc = Tell() == Length();
 318
 319 #else
 320
 321 #if defined(__GNUWIN32__)
 322   int iRc = -1;
 323 #else
 324   int iRc = eof(m_fd);
 325 #endif
 326
 327 #endif
 328
 329   switch ( iRc ) {
 330     case 1:
 331       break;
 332
 333     case 0:
 334       return FALSE;
 335
 336     case -1:
 337       wxLogSysError("can't determine if the end of file is reached on "
 338                     "descriptor %d", m_fd);
 339       break;
 340
 341     default:
 342       wxFAIL_MSG("invalid eof() return value.");
 343   }
 344
 345   return TRUE;
 346 }
 347
 348 // ============================================================================
 349 // implementation of wxTempFile
 350 // ============================================================================
 351
 352 // ----------------------------------------------------------------------------
 353 // construction
 354 // ----------------------------------------------------------------------------
 355 wxTempFile::wxTempFile(const wxString& strName)
 356 {
 357   Open(strName);
 358 }
 359
 360 bool wxTempFile::Open(const wxString& strName)
 361 {
 362   m_strName = strName;
 363   m_strTemp = tmpnam(NULL);
 364   return m_file.Open(m_strTemp, wxFile::write);
 365 }
 366
 367 // ----------------------------------------------------------------------------
 368 // destruction
 369 // ----------------------------------------------------------------------------
 370
 371 wxTempFile::~wxTempFile()
 372 {
 373   if ( IsOpened() )
 374     Discard();
 375 }
 376
 377 bool wxTempFile::Commit()
 378 {
 379   m_file.Close();
 380
 381   if ( wxFile::Exists(m_strName) && remove(m_strName) != 0 ) {
 382     wxLogSysError("can't remove file '%s'", m_strName.c_str());
 383     return FALSE;
 384   }
 385
 386   if ( rename(m_strTemp, m_strName) != 0 ) {
 387     wxLogSysError("can't commit changes to file '%s'", m_strName.c_str());
 388     return FALSE;
 389   }
 390
 391   return TRUE;
 392 }
 393
 394 void wxTempFile::Discard()
 395 {
 396   m_file.Close();
 397   if ( remove(m_strTemp) != 0 )
 398     wxLogSysError("can't remove temporary file '%s'", m_strTemp.c_str());
 399 }