/////////////////////////////////////////////////////////////////////////////

// Name:        wx/file.h

// Purpose:     wxFile - encapsulates low-level "file descriptor"

//              wxTempFile - safely replace the old file

// Author:      Vadim Zeitlin

// Created:     29/01/98

// 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/convauto.h"

// ----------------------------------------------------------------------------

// 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

  // -------------------

  // suppress Xcode 11 warning about shadowing global read() symbol

  wxCLANG_WARNING_SUPPRESS(shadow)

    // 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 };

  wxCLANG_WARNING_RESTORE(shadow)

  // 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_lasterror = 0; }

    // 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_lasterror = 0; }

  // 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_lasterror = 0; }

  int  Detach() { const int fdOld = m_fd; m_fd = fd_invalid; return fdOld; }

  int  fd() const { return m_fd; }

  // read/write (unbuffered)

    // read all data from the file into a string (useful for text files)

  bool ReadAll(wxString *str, const wxMBConv& conv = wxConvAuto());

    // 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 = wxConvAuto());

    // 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_lasterror != 0; }

    // get last errno

  int GetLastError() const { return m_lasterror; }

    // reset error state

  void ClearLastError() { m_lasterror = 0; }

    // 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&);

  // Copy the value of errno into m_lasterror if rc == -1 and return true in

  // this case (indicating that we've got an error). Otherwise return false.

  //

  // Notice that we use the possibly 64 bit wxFileOffset instead of int here so

  // that it works for checking the result of functions such as tell() too.

  bool CheckForError(wxFileOffset rc) const;

  int m_fd; // file descriptor or INVALID_FD if not opened

  int m_lasterror; // errno value of last error

};

// ----------------------------------------------------------------------------

// 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() = default;

    // associates the temp file with the file to be replaced and opens it

  explicit 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__