190 lines
6.7 KiB
C++
190 lines
6.7 KiB
C++
/////////////////////////////////////////////////////////////////////////////
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// Name: wx/file.h
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// Purpose: wxFile - encapsulates low-level "file descriptor"
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// wxTempFile - safely replace the old file
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// Author: Vadim Zeitlin
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// Modified by:
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// Created: 29/01/98
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// RCS-ID: $Id: file.h 67254 2011-03-20 00:14:35Z DS $
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// Copyright: (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
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// Licence: wxWindows licence
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/////////////////////////////////////////////////////////////////////////////
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#ifndef _WX_FILEH__
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#define _WX_FILEH__
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#include "wx/defs.h"
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#if wxUSE_FILE
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#include "wx/string.h"
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#include "wx/filefn.h"
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#include "wx/strconv.h"
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// ----------------------------------------------------------------------------
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// class wxFile: raw file IO
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//
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// NB: for space efficiency this class has no virtual functions, including
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// dtor which is _not_ virtual, so it shouldn't be used as a base class.
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// ----------------------------------------------------------------------------
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class WXDLLIMPEXP_BASE wxFile
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{
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public:
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// more file constants
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// -------------------
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// opening mode
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enum OpenMode { read, write, read_write, write_append, write_excl };
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// standard values for file descriptor
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enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
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// static functions
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// ----------------
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// check whether a regular file by this name exists
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static bool Exists(const wxString& name);
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// check whether we can access the given file in given mode
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// (only read and write make sense here)
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static bool Access(const wxString& name, OpenMode mode);
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// ctors
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// -----
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// def ctor
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wxFile() { m_fd = fd_invalid; m_lasterror = 0; }
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// open specified file (may fail, use IsOpened())
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wxFile(const wxString& fileName, OpenMode mode = read);
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// attach to (already opened) file
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wxFile(int lfd) { m_fd = lfd; m_lasterror = 0; }
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// open/close
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// create a new file (with the default value of bOverwrite, it will fail if
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// the file already exists, otherwise it will overwrite it and succeed)
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bool Create(const wxString& fileName, bool bOverwrite = false,
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int access = wxS_DEFAULT);
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bool Open(const wxString& fileName, OpenMode mode = read,
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int access = wxS_DEFAULT);
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bool Close(); // Close is a NOP if not opened
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// assign an existing file descriptor and get it back from wxFile object
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void Attach(int lfd) { Close(); m_fd = lfd; m_lasterror = 0; }
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void Detach() { m_fd = fd_invalid; }
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int fd() const { return m_fd; }
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// read/write (unbuffered)
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// returns number of bytes read or wxInvalidOffset on error
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ssize_t Read(void *pBuf, size_t nCount);
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// returns the number of bytes written
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size_t Write(const void *pBuf, size_t nCount);
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// returns true on success
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bool Write(const wxString& s, const wxMBConv& conv = wxMBConvUTF8());
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// flush data not yet written
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bool Flush();
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// file pointer operations (return wxInvalidOffset on failure)
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// move ptr ofs bytes related to start/current offset/end of file
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wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart);
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// move ptr to ofs bytes before the end
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wxFileOffset SeekEnd(wxFileOffset ofs = 0) { return Seek(ofs, wxFromEnd); }
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// get current offset
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wxFileOffset Tell() const;
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// get current file length
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wxFileOffset Length() const;
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// simple accessors
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// is file opened?
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bool IsOpened() const { return m_fd != fd_invalid; }
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// is end of file reached?
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bool Eof() const;
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// has an error occurred?
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bool Error() const { return m_lasterror != 0; }
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// get last errno
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int GetLastError() const { return m_lasterror; }
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// reset error state
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void ClearLastError() { m_lasterror = 0; }
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// type such as disk or pipe
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wxFileKind GetKind() const { return wxGetFileKind(m_fd); }
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// dtor closes the file if opened
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~wxFile() { Close(); }
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private:
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// copy ctor and assignment operator are private because
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// it doesn't make sense to copy files this way:
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// attempt to do it will provoke a compile-time error.
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wxFile(const wxFile&);
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wxFile& operator=(const wxFile&);
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// Copy the value of errno into m_lasterror if rc == -1 and return true in
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// this case (indicating that we've got an error). Otherwise return false.
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//
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// Notice that we use the possibly 64 bit wxFileOffset instead of int here so
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// that it works for checking the result of functions such as tell() too.
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bool CheckForError(wxFileOffset rc) const;
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int m_fd; // file descriptor or INVALID_FD if not opened
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int m_lasterror; // errno value of last error
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};
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// ----------------------------------------------------------------------------
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// class wxTempFile: if you want to replace another file, create an instance
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// of wxTempFile passing the name of the file to be replaced to the ctor. Then
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// you can write to wxTempFile and call Commit() function to replace the old
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// file (and close this one) or call Discard() to cancel the modification. If
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// you call neither of them, dtor will call Discard().
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// ----------------------------------------------------------------------------
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class WXDLLIMPEXP_BASE wxTempFile
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{
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public:
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// ctors
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// default
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wxTempFile() { }
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// associates the temp file with the file to be replaced and opens it
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wxTempFile(const wxString& strName);
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// open the temp file (strName is the name of file to be replaced)
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bool Open(const wxString& strName);
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// is the file opened?
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bool IsOpened() const { return m_file.IsOpened(); }
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// get current file length
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wxFileOffset Length() const { return m_file.Length(); }
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// move ptr ofs bytes related to start/current offset/end of file
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wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart)
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{ return m_file.Seek(ofs, mode); }
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// get current offset
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wxFileOffset Tell() const { return m_file.Tell(); }
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// I/O (both functions return true on success, false on failure)
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bool Write(const void *p, size_t n) { return m_file.Write(p, n) == n; }
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bool Write(const wxString& str, const wxMBConv& conv = wxMBConvUTF8())
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{ return m_file.Write(str, conv); }
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// flush data: can be called before closing file to ensure that data was
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// correctly written out
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bool Flush() { return m_file.Flush(); }
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// different ways to close the file
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// validate changes and delete the old file of name m_strName
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bool Commit();
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// discard changes
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void Discard();
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// dtor calls Discard() if file is still opened
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~wxTempFile();
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private:
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// no copy ctor/assignment operator
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wxTempFile(const wxTempFile&);
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wxTempFile& operator=(const wxTempFile&);
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wxString m_strName, // name of the file to replace in Commit()
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m_strTemp; // temporary file name
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wxFile m_file; // the temporary file
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};
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#endif // wxUSE_FILE
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#endif // _WX_FILEH__
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