src/common/file.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        file.cpp
// Purpose:     wxFile - encapsulates low-level "file descriptor"
//              wxTempFile
// Author:      Vadim Zeitlin
// Modified by:
// Created:     29/01/98
// RCS-ID:      $Id: file.cpp 42876 2006-10-31 23:29:02Z SN $
// Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
  #pragma hdrstop
#endif

#if wxUSE_FILE

// standard
#if defined(__WXMSW__) && !defined(__GNUWIN32__) && !defined(__WXMICROWIN__) && !defined(__WXWINCE__)

#ifndef __SALFORDC__
    #define   WIN32_LEAN_AND_MEAN
    #define   NOSERVICE
    #define   NOIME
    #define   NOATOM
    #define   NOGDI
    #define   NOGDICAPMASKS
    #define   NOMETAFILE
    #define   NOMINMAX
    #define   NOMSG
    #define   NOOPENFILE
    #define   NORASTEROPS
    #define   NOSCROLL
    #define   NOSOUND
    #define   NOSYSMETRICS
    #define   NOTEXTMETRIC
    #define   NOWH
    #define   NOCOMM
    #define   NOKANJI
    #define   NOCRYPT
    #define   NOMCX
#endif

#elif defined(__WXMSW__) && defined(__WXWINCE__)
    #include  "wx/msw/missing.h"
#elif (defined(__OS2__))
    #include <io.h>
#elif (defined(__UNIX__) || defined(__GNUWIN32__))
    #include  <unistd.h>
    #include  <time.h>
    #include  <sys/stat.h>
    #ifdef __GNUWIN32__
        #include "wx/msw/wrapwin.h"
    #endif
#elif defined(__DOS__)
    #if defined(__WATCOMC__)
       #include <io.h>
    #elif defined(__DJGPP__)
       #include <io.h>
       #include <unistd.h>
       #include <stdio.h>
    #else
        #error  "Please specify the header with file functions declarations."
    #endif
#elif (defined(__WXSTUBS__))
    // Have to ifdef this for different environments
    #include <io.h>
#elif (defined(__WXMAC__))
#if __MSL__ < 0x6000
    int access( const char *path, int mode ) { return 0 ; }
#else
    int _access( const char *path, int mode ) { return 0 ; }
#endif
    char* mktemp( char * path ) { return path ;}
    #include <stat.h>
    #include <unistd.h>
#else
    #error  "Please specify the header with file functions declarations."
#endif  //Win/UNIX

#include  <stdio.h>       // SEEK_xxx constants

// Windows compilers don't have these constants
#ifndef W_OK
    enum
    {
        F_OK = 0,   // test for existence
        X_OK = 1,   //          execute permission
        W_OK = 2,   //          write
        R_OK = 4    //          read
    };
#endif // W_OK

#ifdef __SALFORDC__
    #include <unix.h>
#endif

// some broken compilers don't have 3rd argument in open() and creat()
#ifdef __SALFORDC__
    #define ACCESS(access)
    #define stat    _stat
#else // normal compiler
    #define ACCESS(access)  , (access)
#endif // Salford C

// wxWidgets
#ifndef WX_PRECOMP
    #include  "wx/string.h"
    #include  "wx/intl.h"
    #include  "wx/log.h"
#endif // !WX_PRECOMP

#include  "wx/filename.h"
#include  "wx/file.h"
#include  "wx/filefn.h"

// there is no distinction between text and binary files under Unix, so define
// O_BINARY as 0 if the system headers don't do it already
#if defined(__UNIX__) && !defined(O_BINARY)
    #define   O_BINARY    (0)
#endif  //__UNIX__

#ifdef __WXMSW__
    #include "wx/msw/mslu.h"
#endif

#ifdef __WXWINCE__
    #include "wx/msw/private.h"
#endif

#ifndef MAX_PATH
    #define MAX_PATH 512
#endif

// ============================================================================
// implementation of wxFile
// ============================================================================

// ----------------------------------------------------------------------------
// static functions
// ----------------------------------------------------------------------------

bool wxFile::Exists(const wxChar *name)
{
    return wxFileExists(name);
}

bool wxFile::Access(const wxChar *name, OpenMode mode)
{
    int how;

    switch ( mode )
    {
        default:
            wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
            // fall through

        case read:
            how = R_OK;
            break;

        case write:
            how = W_OK;
            break;

        case read_write:
            how = R_OK | W_OK;
            break;
    }

    return wxAccess(name, how) == 0;
}

// ----------------------------------------------------------------------------
// opening/closing
// ----------------------------------------------------------------------------

// ctors
wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
{
    m_fd = fd_invalid;
    m_error = false;

    Open(szFileName, mode);
}

// create the file, fail if it already exists and bOverwrite
bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
{
    // if bOverwrite we create a new file or truncate the existing one,
    // otherwise we only create the new file and fail if it already exists
#if defined(__WXMAC__) && !defined(__UNIX__) && !wxUSE_UNICODE
    // Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
    // int fd = open( szFileName , O_CREAT | (bOverwrite ? O_TRUNC : O_EXCL), access);
    int fd = creat( szFileName , accessMode);
#else
    int fd = wxOpen( szFileName,
                     O_BINARY | O_WRONLY | O_CREAT |
                     (bOverwrite ? O_TRUNC : O_EXCL)
                     ACCESS(accessMode) );
#endif
    if ( fd == -1 )
    {
        wxLogSysError(_("can't create file '%s'"), szFileName);
        return false;
    }

    Attach(fd);
    return true;
}

// open the file
bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
{
    int flags = O_BINARY;

    switch ( mode )
    {
        case read:
            flags |= O_RDONLY;
            break;

        case write_append:
            if ( wxFile::Exists(szFileName) )
            {
                flags |= O_WRONLY | O_APPEND;
                break;
            }
            //else: fall through as write_append is the same as write if the
            //      file doesn't exist

        case write:
            flags |= O_WRONLY | O_CREAT | O_TRUNC;
            break;

        case write_excl:
            flags |= O_WRONLY | O_CREAT | O_EXCL;
            break;

        case read_write:
            flags |= O_RDWR;
            break;
    }

#ifdef __WINDOWS__
    // only read/write bits for "all" are supported by this function under
    // Windows, and VC++ 8 returns EINVAL if any other bits are used in
    // accessMode, so clear them as they have at best no effect anyhow
    accessMode &= wxS_IRUSR | wxS_IWUSR;
#endif // __WINDOWS__

    int fd = wxOpen( szFileName, flags ACCESS(accessMode));

    if ( fd == -1 )
    {
        wxLogSysError(_("can't open file '%s'"), szFileName);
        return false;
    }

    Attach(fd);
    return true;
}

// close
bool wxFile::Close()
{
    if ( IsOpened() ) {
        if (wxClose(m_fd) == -1)
        {
            wxLogSysError(_("can't close file descriptor %d"), m_fd);
            m_fd = fd_invalid;
            return false;
        }
        else
            m_fd = fd_invalid;
    }

    return true;
}

// ----------------------------------------------------------------------------
// read/write
// ----------------------------------------------------------------------------

// read
ssize_t wxFile::Read(void *pBuf, size_t nCount)
{
    wxCHECK( (pBuf != NULL) && IsOpened(), 0 );

    ssize_t iRc = wxRead(m_fd, pBuf, nCount);

    if ( iRc == -1 )
    {
        wxLogSysError(_("can't read from file descriptor %d"), m_fd);
        return wxInvalidOffset;
    }

    return iRc;
}

// write
size_t wxFile::Write(const void *pBuf, size_t nCount)
{
    wxCHECK( (pBuf != NULL) && IsOpened(), 0 );

    ssize_t iRc = wxWrite(m_fd, pBuf, nCount);

    if ( iRc == -1 )
    {
        wxLogSysError(_("can't write to file descriptor %d"), m_fd);
        m_error = true;
        iRc = 0;
    }

    return iRc;
}

// flush
bool wxFile::Flush()
{
#ifdef HAVE_FSYNC
    // fsync() only works on disk files and returns errors for pipes, don't
    // call it then
    if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
    {
        if ( wxFsync(m_fd) == -1 )
        {
            wxLogSysError(_("can't flush file descriptor %d"), m_fd);
            return false;
        }
    }
#endif // HAVE_FSYNC

    return true;
}

// ----------------------------------------------------------------------------
// seek
// ----------------------------------------------------------------------------

// seek
wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
{
    wxASSERT_MSG( IsOpened(), _T("can't seek on closed file") );
    wxCHECK_MSG( ofs != wxInvalidOffset || mode != wxFromStart,
                 wxInvalidOffset,
                 _T("invalid absolute file offset") );

    int origin;
    switch ( mode ) {
        default:
            wxFAIL_MSG(_("unknown seek origin"));

        case wxFromStart:
            origin = SEEK_SET;
            break;

        case wxFromCurrent:
            origin = SEEK_CUR;
            break;

        case wxFromEnd:
            origin = SEEK_END;
            break;
    }

    wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
    if ( iRc == wxInvalidOffset )
    {
        wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
    }

    return iRc;
}

// get current file offset
wxFileOffset wxFile::Tell() const
{
    wxASSERT( IsOpened() );

    wxFileOffset iRc = wxTell(m_fd);
    if ( iRc == wxInvalidOffset )
    {
        wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
    }

    return iRc;
}

// get current file length
wxFileOffset wxFile::Length() const
{
    wxASSERT( IsOpened() );

    wxFileOffset iRc = Tell();
    if ( iRc != wxInvalidOffset ) {
        // have to use const_cast :-(
        wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
        if ( iLen != wxInvalidOffset ) {
            // restore old position
            if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
                // error
                iLen = wxInvalidOffset;
            }
        }

        iRc = iLen;
    }

    if ( iRc == wxInvalidOffset )
    {
        wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
    }

    return iRc;
}

// is end of file reached?
bool wxFile::Eof() const
{
    wxASSERT( IsOpened() );

    wxFileOffset iRc;

#if defined(__DOS__) || defined(__UNIX__) || defined(__GNUWIN32__) || defined( __MWERKS__ ) || defined(__SALFORDC__)
    // @@ this doesn't work, of course, on unseekable file descriptors
    wxFileOffset ofsCur = Tell(),
    ofsMax = Length();
    if ( ofsCur == wxInvalidOffset || ofsMax == wxInvalidOffset )
        iRc = wxInvalidOffset;
    else
        iRc = ofsCur == ofsMax;
#else  // Windows and "native" compiler
    iRc = wxEof(m_fd);
#endif // Windows/Unix

    if ( iRc == 1)
        {}
    else if ( iRc == 0 )
        return false;
    else if ( iRc == wxInvalidOffset )
        wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
    else
        wxFAIL_MSG(_("invalid eof() return value."));

    return true;
}

// ============================================================================
// implementation of wxTempFile
// ============================================================================

// ----------------------------------------------------------------------------
// construction
// ----------------------------------------------------------------------------

wxTempFile::wxTempFile(const wxString& strName)
{
    Open(strName);
}

bool wxTempFile::Open(const wxString& strName)
{
    // we must have an absolute filename because otherwise CreateTempFileName()
    // would create the temp file in $TMP (i.e. the system standard location
    // for the temp files) which might be on another volume/drive/mount and
    // wxRename()ing it later to m_strName from Commit() would then fail
    //
    // with the absolute filename, the temp file is created in the same
    // directory as this one which ensures that wxRename() may work later
    wxFileName fn(strName);
    if ( !fn.IsAbsolute() )
    {
        fn.Normalize(wxPATH_NORM_ABSOLUTE);
    }

    m_strName = fn.GetFullPath();

    m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);

    if ( m_strTemp.empty() )
    {
        // CreateTempFileName() failed
        return false;
    }

#ifdef __UNIX__
    // the temp file should have the same permissions as the original one
    mode_t mode;

    wxStructStat st;
    if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
    {
        mode = st.st_mode;
    }
    else
    {
        // file probably didn't exist, just give it the default mode _using_
        // user's umask (new files creation should respect umask)
        mode_t mask = umask(0777);
        mode = 0666 & ~mask;
        umask(mask);
    }

    if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
    {
#ifndef __OS2__
        wxLogSysError(_("Failed to set temporary file permissions"));
#endif
    }
#endif // Unix

    return true;
}

// ----------------------------------------------------------------------------
// destruction
// ----------------------------------------------------------------------------

wxTempFile::~wxTempFile()
{
    if ( IsOpened() )
        Discard();
}

bool wxTempFile::Commit()
{
    m_file.Close();

    if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
        wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
        return false;
    }

    if ( !wxRenameFile(m_strTemp, m_strName)  ) {
        wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
        return false;
    }

    return true;
}

void wxTempFile::Discard()
{
    m_file.Close();
    if ( wxRemove(m_strTemp) != 0 )
        wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
}

#endif // wxUSE_FILE

1	william	31	/////////////////////////////////////////////////////////////////////////////
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: file.cpp 42876 2006-10-31 23:29:02Z SN $
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			#ifndef __SALFORDC__
30			#define WIN32_LEAN_AND_MEAN
31			#define NOSERVICE
32			#define NOIME
33			#define NOATOM
34			#define NOGDI
35			#define NOGDICAPMASKS
36			#define NOMETAFILE
37			#define NOMINMAX
38			#define NOMSG
39			#define NOOPENFILE
40			#define NORASTEROPS
41			#define NOSCROLL
42			#define NOSOUND
43			#define NOSYSMETRICS
44			#define NOTEXTMETRIC
45			#define NOWH
46			#define NOCOMM
47			#define NOKANJI
48			#define NOCRYPT
49			#define NOMCX
50			#endif
51
52			#elif defined(__WXMSW__) && defined(__WXWINCE__)
53			#include "wx/msw/missing.h"
54			#elif (defined(__OS2__))
55			#include <io.h>
56			#elif (defined(__UNIX__) \|\| defined(__GNUWIN32__))
57			#include <unistd.h>
58			#include <time.h>
59			#include <sys/stat.h>
60			#ifdef __GNUWIN32__
61			#include "wx/msw/wrapwin.h"
62			#endif
63			#elif defined(__DOS__)
64			#if defined(__WATCOMC__)
65			#include <io.h>
66			#elif defined(__DJGPP__)
67			#include <io.h>
68			#include <unistd.h>
69			#include <stdio.h>
70			#else
71			#error "Please specify the header with file functions declarations."
72			#endif
73			#elif (defined(__WXSTUBS__))
74			// Have to ifdef this for different environments
75			#include <io.h>
76			#elif (defined(__WXMAC__))
77			#if __MSL__ < 0x6000
78			int access( const char *path, int mode ) { return 0 ; }
79			#else
80			int _access( const char *path, int mode ) { return 0 ; }
81			#endif
82			char* mktemp( char * path ) { return path ;}
83			#include <stat.h>
84			#include <unistd.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			// Windows compilers don't have these constants
92			#ifndef W_OK
93			enum
94			{
95			F_OK = 0, // test for existence
96			X_OK = 1, // execute permission
97			W_OK = 2, // write
98			R_OK = 4 // read
99			};
100			#endif // W_OK
101
102			#ifdef __SALFORDC__
103			#include <unix.h>
104			#endif
105
106			// some broken compilers don't have 3rd argument in open() and creat()
107			#ifdef __SALFORDC__
108			#define ACCESS(access)
109			#define stat _stat
110			#else // normal compiler
111			#define ACCESS(access) , (access)
112			#endif // Salford C
113
114			// wxWidgets
115			#ifndef WX_PRECOMP
116			#include "wx/string.h"
117			#include "wx/intl.h"
118			#include "wx/log.h"
119			#endif // !WX_PRECOMP
120
121			#include "wx/filename.h"
122			#include "wx/file.h"
123			#include "wx/filefn.h"
124
125			// there is no distinction between text and binary files under Unix, so define
126			// O_BINARY as 0 if the system headers don't do it already
127			#if defined(__UNIX__) && !defined(O_BINARY)
128			#define O_BINARY (0)
129			#endif //__UNIX__
130
131			#ifdef __WXMSW__
132			#include "wx/msw/mslu.h"
133			#endif
134
135			#ifdef __WXWINCE__
136			#include "wx/msw/private.h"
137			#endif
138
139			#ifndef MAX_PATH
140			#define MAX_PATH 512
141			#endif
142
143			// ============================================================================
144			// implementation of wxFile
145			// ============================================================================
146
147			// ----------------------------------------------------------------------------
148			// static functions
149			// ----------------------------------------------------------------------------
150
151			bool wxFile::Exists(const wxChar *name)
152			{
153			return wxFileExists(name);
154			}
155
156			bool wxFile::Access(const wxChar *name, OpenMode mode)
157			{
158			int how;
159
160			switch ( mode )
161			{
162			default:
163			wxFAIL_MSG(wxT("bad wxFile::Access mode parameter."));
164			// fall through
165
166			case read:
167			how = R_OK;
168			break;
169
170			case write:
171			how = W_OK;
172			break;
173
174			case read_write:
175			how = R_OK \| W_OK;
176			break;
177			}
178
179			return wxAccess(name, how) == 0;
180			}
181
182			// ----------------------------------------------------------------------------
183			// opening/closing
184			// ----------------------------------------------------------------------------
185
186			// ctors
187			wxFile::wxFile(const wxChar *szFileName, OpenMode mode)
188			{
189			m_fd = fd_invalid;
190			m_error = false;
191
192			Open(szFileName, mode);
193			}
194
195			// create the file, fail if it already exists and bOverwrite
196			bool wxFile::Create(const wxChar *szFileName, bool bOverwrite, int accessMode)
197			{
198			// if bOverwrite we create a new file or truncate the existing one,
199			// otherwise we only create the new file and fail if it already exists
200			#if defined(__WXMAC__) && !defined(__UNIX__) && !wxUSE_UNICODE
201			// Dominic Mazzoni [dmazzoni+@cs.cmu.edu] reports that open is still broken on the mac, so we replace
202			// int fd = open( szFileName , O_CREAT \| (bOverwrite ? O_TRUNC : O_EXCL), access);
203			int fd = creat( szFileName , accessMode);
204			#else
205			int fd = wxOpen( szFileName,
206			O_BINARY \| O_WRONLY \| O_CREAT \|
207			(bOverwrite ? O_TRUNC : O_EXCL)
208			ACCESS(accessMode) );
209			#endif
210			if ( fd == -1 )
211			{
212			wxLogSysError(_("can't create file '%s'"), szFileName);
213			return false;
214			}
215
216			Attach(fd);
217			return true;
218			}
219
220			// open the file
221			bool wxFile::Open(const wxChar *szFileName, OpenMode mode, int accessMode)
222			{
223			int flags = O_BINARY;
224
225			switch ( mode )
226			{
227			case read:
228			flags \|= O_RDONLY;
229			break;
230
231			case write_append:
232			if ( wxFile::Exists(szFileName) )
233			{
234			flags \|= O_WRONLY \| O_APPEND;
235			break;
236			}
237			//else: fall through as write_append is the same as write if the
238			// file doesn't exist
239
240			case write:
241			flags \|= O_WRONLY \| O_CREAT \| O_TRUNC;
242			break;
243
244			case write_excl:
245			flags \|= O_WRONLY \| O_CREAT \| O_EXCL;
246			break;
247
248			case read_write:
249			flags \|= O_RDWR;
250			break;
251			}
252
253			#ifdef __WINDOWS__
254			// only read/write bits for "all" are supported by this function under
255			// Windows, and VC++ 8 returns EINVAL if any other bits are used in
256			// accessMode, so clear them as they have at best no effect anyhow
257			accessMode &= wxS_IRUSR \| wxS_IWUSR;
258			#endif // __WINDOWS__
259
260			int fd = wxOpen( szFileName, flags ACCESS(accessMode));
261
262			if ( fd == -1 )
263			{
264			wxLogSysError(_("can't open file '%s'"), szFileName);
265			return false;
266			}
267
268			Attach(fd);
269			return true;
270			}
271
272			// close
273			bool wxFile::Close()
274			{
275			if ( IsOpened() ) {
276			if (wxClose(m_fd) == -1)
277			{
278			wxLogSysError(_("can't close file descriptor %d"), m_fd);
279			m_fd = fd_invalid;
280			return false;
281			}
282			else
283			m_fd = fd_invalid;
284			}
285
286			return true;
287			}
288
289			// ----------------------------------------------------------------------------
290			// read/write
291			// ----------------------------------------------------------------------------
292
293			// read
294			ssize_t wxFile::Read(void *pBuf, size_t nCount)
295			{
296			wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
297
298			ssize_t iRc = wxRead(m_fd, pBuf, nCount);
299
300			if ( iRc == -1 )
301			{
302			wxLogSysError(_("can't read from file descriptor %d"), m_fd);
303			return wxInvalidOffset;
304			}
305
306			return iRc;
307			}
308
309			// write
310			size_t wxFile::Write(const void *pBuf, size_t nCount)
311			{
312			wxCHECK( (pBuf != NULL) && IsOpened(), 0 );
313
314			ssize_t iRc = wxWrite(m_fd, pBuf, nCount);
315
316			if ( iRc == -1 )
317			{
318			wxLogSysError(_("can't write to file descriptor %d"), m_fd);
319			m_error = true;
320			iRc = 0;
321			}
322
323			return iRc;
324			}
325
326			// flush
327			bool wxFile::Flush()
328			{
329			#ifdef HAVE_FSYNC
330			// fsync() only works on disk files and returns errors for pipes, don't
331			// call it then
332			if ( IsOpened() && GetKind() == wxFILE_KIND_DISK )
333			{
334			if ( wxFsync(m_fd) == -1 )
335			{
336			wxLogSysError(_("can't flush file descriptor %d"), m_fd);
337			return false;
338			}
339			}
340			#endif // HAVE_FSYNC
341
342			return true;
343			}
344
345			// ----------------------------------------------------------------------------
346			// seek
347			// ----------------------------------------------------------------------------
348
349			// seek
350			wxFileOffset wxFile::Seek(wxFileOffset ofs, wxSeekMode mode)
351			{
352			wxASSERT_MSG( IsOpened(), _T("can't seek on closed file") );
353			wxCHECK_MSG( ofs != wxInvalidOffset \|\| mode != wxFromStart,
354			wxInvalidOffset,
355			_T("invalid absolute file offset") );
356
357			int origin;
358			switch ( mode ) {
359			default:
360			wxFAIL_MSG(_("unknown seek origin"));
361
362			case wxFromStart:
363			origin = SEEK_SET;
364			break;
365
366			case wxFromCurrent:
367			origin = SEEK_CUR;
368			break;
369
370			case wxFromEnd:
371			origin = SEEK_END;
372			break;
373			}
374
375			wxFileOffset iRc = wxSeek(m_fd, ofs, origin);
376			if ( iRc == wxInvalidOffset )
377			{
378			wxLogSysError(_("can't seek on file descriptor %d"), m_fd);
379			}
380
381			return iRc;
382			}
383
384			// get current file offset
385			wxFileOffset wxFile::Tell() const
386			{
387			wxASSERT( IsOpened() );
388
389			wxFileOffset iRc = wxTell(m_fd);
390			if ( iRc == wxInvalidOffset )
391			{
392			wxLogSysError(_("can't get seek position on file descriptor %d"), m_fd);
393			}
394
395			return iRc;
396			}
397
398			// get current file length
399			wxFileOffset wxFile::Length() const
400			{
401			wxASSERT( IsOpened() );
402
403			wxFileOffset iRc = Tell();
404			if ( iRc != wxInvalidOffset ) {
405			// have to use const_cast :-(
406			wxFileOffset iLen = ((wxFile *)this)->SeekEnd();
407			if ( iLen != wxInvalidOffset ) {
408			// restore old position
409			if ( ((wxFile *)this)->Seek(iRc) == wxInvalidOffset ) {
410			// error
411			iLen = wxInvalidOffset;
412			}
413			}
414
415			iRc = iLen;
416			}
417
418			if ( iRc == wxInvalidOffset )
419			{
420			wxLogSysError(_("can't find length of file on file descriptor %d"), m_fd);
421			}
422
423			return iRc;
424			}
425
426			// is end of file reached?
427			bool wxFile::Eof() const
428			{
429			wxASSERT( IsOpened() );
430
431			wxFileOffset iRc;
432
433			#if defined(__DOS__) \|\| defined(__UNIX__) \|\| defined(__GNUWIN32__) \|\| defined( __MWERKS__ ) \|\| defined(__SALFORDC__)
434			// @@ this doesn't work, of course, on unseekable file descriptors
435			wxFileOffset ofsCur = Tell(),
436			ofsMax = Length();
437			if ( ofsCur == wxInvalidOffset \|\| ofsMax == wxInvalidOffset )
438			iRc = wxInvalidOffset;
439			else
440			iRc = ofsCur == ofsMax;
441			#else // Windows and "native" compiler
442			iRc = wxEof(m_fd);
443			#endif // Windows/Unix
444
445			if ( iRc == 1)
446			{}
447			else if ( iRc == 0 )
448			return false;
449			else if ( iRc == wxInvalidOffset )
450			wxLogSysError(_("can't determine if the end of file is reached on descriptor %d"), m_fd);
451			else
452			wxFAIL_MSG(_("invalid eof() return value."));
453
454			return true;
455			}
456
457			// ============================================================================
458			// implementation of wxTempFile
459			// ============================================================================
460
461			// ----------------------------------------------------------------------------
462			// construction
463			// ----------------------------------------------------------------------------
464
465			wxTempFile::wxTempFile(const wxString& strName)
466			{
467			Open(strName);
468			}
469
470			bool wxTempFile::Open(const wxString& strName)
471			{
472			// we must have an absolute filename because otherwise CreateTempFileName()
473			// would create the temp file in $TMP (i.e. the system standard location
474			// for the temp files) which might be on another volume/drive/mount and
475			// wxRename()ing it later to m_strName from Commit() would then fail
476			//
477			// with the absolute filename, the temp file is created in the same
478			// directory as this one which ensures that wxRename() may work later
479			wxFileName fn(strName);
480			if ( !fn.IsAbsolute() )
481			{
482			fn.Normalize(wxPATH_NORM_ABSOLUTE);
483			}
484
485			m_strName = fn.GetFullPath();
486
487			m_strTemp = wxFileName::CreateTempFileName(m_strName, &m_file);
488
489			if ( m_strTemp.empty() )
490			{
491			// CreateTempFileName() failed
492			return false;
493			}
494
495			#ifdef __UNIX__
496			// the temp file should have the same permissions as the original one
497			mode_t mode;
498
499			wxStructStat st;
500			if ( stat( (const char*) m_strName.fn_str(), &st) == 0 )
501			{
502			mode = st.st_mode;
503			}
504			else
505			{
506			// file probably didn't exist, just give it the default mode _using_
507			// user's umask (new files creation should respect umask)
508			mode_t mask = umask(0777);
509			mode = 0666 & ~mask;
510			umask(mask);
511			}
512
513			if ( chmod( (const char*) m_strTemp.fn_str(), mode) == -1 )
514			{
515			#ifndef __OS2__
516			wxLogSysError(_("Failed to set temporary file permissions"));
517			#endif
518			}
519			#endif // Unix
520
521			return true;
522			}
523
524			// ----------------------------------------------------------------------------
525			// destruction
526			// ----------------------------------------------------------------------------
527
528			wxTempFile::~wxTempFile()
529			{
530			if ( IsOpened() )
531			Discard();
532			}
533
534			bool wxTempFile::Commit()
535			{
536			m_file.Close();
537
538			if ( wxFile::Exists(m_strName) && wxRemove(m_strName) != 0 ) {
539			wxLogSysError(_("can't remove file '%s'"), m_strName.c_str());
540			return false;
541			}
542
543			if ( !wxRenameFile(m_strTemp, m_strName) ) {
544			wxLogSysError(_("can't commit changes to file '%s'"), m_strName.c_str());
545			return false;
546			}
547
548			return true;
549			}
550
551			void wxTempFile::Discard()
552			{
553			m_file.Close();
554			if ( wxRemove(m_strTemp) != 0 )
555			wxLogSysError(_("can't remove temporary file '%s'"), m_strTemp.c_str());
556			}
557
558			#endif // wxUSE_FILE
559