file.cpp
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CPP
568 行
/////////////////////////////////////////////////////////////////////////////
// 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,v 1.97 2005/09/19 23:34:07 VZ Exp $
// Copyright: (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------
#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
#pragma implementation "file.h"
#endif
// 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
// 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 __SALFORDC__
#include <unix.h>
#endif
#ifndef MAX_PATH
#define MAX_PATH 512
#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"
#ifdef __WXMSW__
#include "wx/msw/mslu.h"
#endif
#ifdef __WXWINCE__
#include "wx/msw/private.h"
#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;
}
else
{
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;
}
else {
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()
{
#if defined(__VISUALC__) || defined(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 // 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
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