wxWidgets/include/wx/file.h
2009-11-05 14:59:30 +00:00

226 lines
8.1 KiB
C++

/////////////////////////////////////////////////////////////////////////////
// Name: file.h
// Purpose: wxFile - encapsulates low-level "file descriptor"
// wxTempFile - safely replace the old file
// Author: Vadim Zeitlin
// Modified by:
// Created: 29/01/98
// RCS-ID: $Id$
// Copyright: (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_FILEH__
#define _WX_FILEH__
#include "wx/defs.h"
#if wxUSE_FILE
#include "wx/string.h"
#include "wx/filefn.h"
#include "wx/strconv.h"
// ----------------------------------------------------------------------------
// constants
// ----------------------------------------------------------------------------
// we redefine these constants here because S_IREAD &c are _not_ standard
// however, we do assume that the values correspond to the Unix umask bits
enum wxPosixPermissions
{
// standard Posix names for these permission flags:
wxS_IRUSR = 00400,
wxS_IWUSR = 00200,
wxS_IXUSR = 00100,
wxS_IRGRP = 00040,
wxS_IWGRP = 00020,
wxS_IXGRP = 00010,
wxS_IROTH = 00004,
wxS_IWOTH = 00002,
wxS_IXOTH = 00001,
// longer but more readable synonyms for the constants above:
wxPOSIX_USER_READ = wxS_IRUSR,
wxPOSIX_USER_WRITE = wxS_IWUSR,
wxPOSIX_USER_EXECUTE = wxS_IXUSR,
wxPOSIX_GROUP_READ = wxS_IRGRP,
wxPOSIX_GROUP_WRITE = wxS_IWGRP,
wxPOSIX_GROUP_EXECUTE = wxS_IXGRP,
wxPOSIX_OTHERS_READ = wxS_IROTH,
wxPOSIX_OTHERS_WRITE = wxS_IWOTH,
wxPOSIX_OTHERS_EXECUTE = wxS_IXOTH,
// default mode for the new files: allow reading/writing them to everybody but
// the effective file mode will be set after anding this value with umask and
// so won't include wxS_IW{GRP,OTH} for the default 022 umask value
wxS_DEFAULT = (wxPOSIX_USER_READ | wxPOSIX_USER_WRITE | \
wxPOSIX_GROUP_READ | wxPOSIX_GROUP_WRITE | \
wxPOSIX_OTHERS_READ | wxPOSIX_OTHERS_WRITE),
// default mode for the new directories (see wxFileName::Mkdir): allow
// reading/writing/executing them to everybody, but just like wxS_DEFAULT
// the effective directory mode will be set after anding this value with umask
wxS_DIR_DEFAULT = (wxPOSIX_USER_READ | wxPOSIX_USER_WRITE | wxPOSIX_USER_EXECUTE | \
wxPOSIX_GROUP_READ | wxPOSIX_GROUP_WRITE | wxPOSIX_GROUP_EXECUTE | \
wxPOSIX_OTHERS_READ | wxPOSIX_OTHERS_WRITE | wxPOSIX_OTHERS_EXECUTE)
};
// ----------------------------------------------------------------------------
// class wxFile: raw file IO
//
// NB: for space efficiency this class has no virtual functions, including
// dtor which is _not_ virtual, so it shouldn't be used as a base class.
// ----------------------------------------------------------------------------
class WXDLLIMPEXP_BASE wxFile
{
public:
// more file constants
// -------------------
// opening mode
enum OpenMode { read, write, read_write, write_append, write_excl };
// standard values for file descriptor
enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
// static functions
// ----------------
// check whether a regular file by this name exists
static bool Exists(const wxString& name);
// check whether we can access the given file in given mode
// (only read and write make sense here)
static bool Access(const wxString& name, OpenMode mode);
// ctors
// -----
// def ctor
wxFile() { m_fd = fd_invalid; m_error = false; }
// open specified file (may fail, use IsOpened())
wxFile(const wxString& fileName, OpenMode mode = read);
// attach to (already opened) file
wxFile(int lfd) { m_fd = lfd; m_error = false; }
// open/close
// create a new file (with the default value of bOverwrite, it will fail if
// the file already exists, otherwise it will overwrite it and succeed)
bool Create(const wxString& fileName, bool bOverwrite = false,
int access = wxS_DEFAULT);
bool Open(const wxString& fileName, OpenMode mode = read,
int access = wxS_DEFAULT);
bool Close(); // Close is a NOP if not opened
// assign an existing file descriptor and get it back from wxFile object
void Attach(int lfd) { Close(); m_fd = lfd; m_error = false; }
void Detach() { m_fd = fd_invalid; }
int fd() const { return m_fd; }
// read/write (unbuffered)
// returns number of bytes read or wxInvalidOffset on error
ssize_t Read(void *pBuf, size_t nCount);
// returns the number of bytes written
size_t Write(const void *pBuf, size_t nCount);
// returns true on success
bool Write(const wxString& s, const wxMBConv& conv = wxMBConvUTF8());
// flush data not yet written
bool Flush();
// file pointer operations (return wxInvalidOffset on failure)
// move ptr ofs bytes related to start/current offset/end of file
wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart);
// move ptr to ofs bytes before the end
wxFileOffset SeekEnd(wxFileOffset ofs = 0) { return Seek(ofs, wxFromEnd); }
// get current offset
wxFileOffset Tell() const;
// get current file length
wxFileOffset Length() const;
// simple accessors
// is file opened?
bool IsOpened() const { return m_fd != fd_invalid; }
// is end of file reached?
bool Eof() const;
// has an error occurred?
bool Error() const { return m_error; }
// type such as disk or pipe
wxFileKind GetKind() const { return wxGetFileKind(m_fd); }
// dtor closes the file if opened
~wxFile() { Close(); }
private:
// copy ctor and assignment operator are private because
// it doesn't make sense to copy files this way:
// attempt to do it will provoke a compile-time error.
wxFile(const wxFile&);
wxFile& operator=(const wxFile&);
int m_fd; // file descriptor or INVALID_FD if not opened
bool m_error; // error memory
};
// ----------------------------------------------------------------------------
// class wxTempFile: if you want to replace another file, create an instance
// of wxTempFile passing the name of the file to be replaced to the ctor. Then
// you can write to wxTempFile and call Commit() function to replace the old
// file (and close this one) or call Discard() to cancel the modification. If
// you call neither of them, dtor will call Discard().
// ----------------------------------------------------------------------------
class WXDLLIMPEXP_BASE wxTempFile
{
public:
// ctors
// default
wxTempFile() { }
// associates the temp file with the file to be replaced and opens it
wxTempFile(const wxString& strName);
// open the temp file (strName is the name of file to be replaced)
bool Open(const wxString& strName);
// is the file opened?
bool IsOpened() const { return m_file.IsOpened(); }
// get current file length
wxFileOffset Length() const { return m_file.Length(); }
// move ptr ofs bytes related to start/current offset/end of file
wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart)
{ return m_file.Seek(ofs, mode); }
// get current offset
wxFileOffset Tell() const { return m_file.Tell(); }
// I/O (both functions return true on success, false on failure)
bool Write(const void *p, size_t n) { return m_file.Write(p, n) == n; }
bool Write(const wxString& str, const wxMBConv& conv = wxMBConvUTF8())
{ return m_file.Write(str, conv); }
// flush data: can be called before closing file to ensure that data was
// correctly written out
bool Flush() { return m_file.Flush(); }
// different ways to close the file
// validate changes and delete the old file of name m_strName
bool Commit();
// discard changes
void Discard();
// dtor calls Discard() if file is still opened
~wxTempFile();
private:
// no copy ctor/assignment operator
wxTempFile(const wxTempFile&);
wxTempFile& operator=(const wxTempFile&);
wxString m_strName, // name of the file to replace in Commit()
m_strTemp; // temporary file name
wxFile m_file; // the temporary file
};
#endif // wxUSE_FILE
#endif // _WX_FILEH__