pager.h

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////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1993-2025 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Octave is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////
 
#if ! defined (octave_pager_h)
#define octave_pager_h 1
 
#include "octave-config.h"
 
#include <fstream>
#include <iosfwd>
#include <sstream>
#include <string>
 
class octave_value;
class octave_value_list;
 
OCTAVE_BEGIN_NAMESPACE(octave)
 
class interpreter;
class oprocstream;
 
class OCTINTERP_API pager_buf : public std::stringbuf
{
public:
 
  pager_buf () : std::stringbuf (), m_diary_skip (0) { }
 
  OCTAVE_DISABLE_COPY_MOVE (pager_buf)
 
  ~pager_buf () = default;
 
  void flush_current_contents_to_diary ();
 
  void set_diary_skip ();
 
protected:
 
  int sync ();
 
private:
 
  std::size_t m_diary_skip;
};
 
class OCTINTERP_API pager_stream : public std::ostream
{
public:
 
  pager_stream ();
 
  OCTAVE_DISABLE_COPY_MOVE (pager_stream)
 
  ~pager_stream ();
 
  void flush_current_contents_to_diary ();
 
  void set_diary_skip ();
 
  std::ostream& stream ();
 
  void reset ();
 
private:
 
  pager_buf *m_pb;
};
 
class OCTINTERP_API diary_buf : public std::stringbuf
{
public:
 
  OCTAVE_DEFAULT_CONSTRUCT_DELETE (diary_buf)
  OCTAVE_DISABLE_COPY_MOVE (diary_buf)
 
protected:
 
  int sync ();
};
 
class OCTINTERP_API diary_stream : public std::ostream
{
public:
 
  diary_stream ();
 
  OCTAVE_DISABLE_COPY_MOVE (diary_stream)
 
  ~diary_stream ();
 
  std::ostream& stream ();
 
  void reset ();
 
private:
 
  diary_buf *m_db;
};
 
extern OCTINTERP_API void flush_stdout ();
 
class output_system
{
public:
 
  output_system (interpreter& interp);
 
  OCTAVE_DISABLE_CONSTRUCT_COPY_MOVE (output_system)
 
  ~output_system () = default;
 
  pager_stream& pager () { return m_pager_stream; }
 
  diary_stream& diary () { return m_diary_stream; }
 
  std::string diary_file_name () const { return m_diary_file_name; }
 
  std::string diary_file_name (const std::string& nm)
  {
    std::string val = m_diary_file_name;
    m_diary_file_name = nm.empty () ? "diary" : nm;
    return val;
  }
 
  octave_value PAGER (const octave_value_list& args, int nargout);
 
  std::string PAGER () const { return m_PAGER; }
 
  std::string PAGER (const std::string& s)
  {
    std::string val = m_PAGER;
    m_PAGER = s;
    return val;
  }
 
  octave_value PAGER_FLAGS (const octave_value_list& args, int nargout);
 
  std::string PAGER_FLAGS () const { return m_PAGER_FLAGS; }
 
  std::string PAGER_FLAGS (const std::string& s)
  {
    std::string val = m_PAGER_FLAGS;
    m_PAGER_FLAGS = s;
    return val;
  }
 
  octave_value page_output_immediately (const octave_value_list& args,
                                        int nargout);
 
  bool page_output_immediately () const
  {
    return m_page_output_immediately;
  }
 
  bool page_output_immediately (bool flag)
  {
    bool val = m_page_output_immediately;
    m_page_output_immediately = flag;
    return val;
  }
 
  octave_value page_screen_output (const octave_value_list& args,
                                   int nargout);
 
  bool page_screen_output () const { return m_page_screen_output; }
 
  bool page_screen_output (bool flag)
  {
    bool val = m_page_screen_output;
    m_page_screen_output = flag;
    return val;
  }
 
  bool write_to_diary_file () const
  {
    return m_write_to_diary_file;
  }
 
  bool write_to_diary_file (bool flag)
  {
    bool val = m_write_to_diary_file;
    m_write_to_diary_file = flag;
    return val;
  }
 
  bool really_flush_to_pager () const
  {
    return m_really_flush_to_pager;
  }
 
  bool really_flush_to_pager (bool flag)
  {
    bool val = m_really_flush_to_pager;
    m_really_flush_to_pager = flag;
    return val;
  }
 
  bool flushing_output_to_pager () const
  {
    return m_flushing_output_to_pager;
  }
 
  bool flushing_output_to_pager (bool flag)
  {
    bool val = m_flushing_output_to_pager;
    m_flushing_output_to_pager = flag;
    return val;
  }
 
  std::string pager_command () const;
 
  std::ofstream& external_diary_file () { return m_external_diary_file; }
 
  void reset ();
 
  void flush_stdout ();
 
  bool sync (const char *msg, int len);
 
  void clear_external_pager ();
 
  void open_diary ();
 
  void close_diary ();
 
  std::ostream& __stdout__ () { return m_pager_stream.stream (); }
 
  std::ostream& __diary__ () { return m_diary_stream.stream (); }
 
private:
 
  interpreter& m_interpreter;
 
  pager_stream m_pager_stream;
 
  diary_stream m_diary_stream;
 
  // Our actual connection to the external pager.
  oprocstream *m_external_pager = nullptr;
 
  // The diary file.
  std::ofstream m_external_diary_file;
 
  // The name of the current diary file.
  std::string m_diary_file_name;
 
  // The shell command to run as the pager.
  std::string m_PAGER;
 
  // The options to pass to the pager.
  std::string m_PAGER_FLAGS;
 
  // TRUE means that if output is going to the pager, it is sent as soon
  // as it is available.  Otherwise, it is buffered and only sent to the
  // pager when it is time to print another prompt.
  bool m_page_output_immediately;
 
  // TRUE means all output intended for the screen should be passed
  // through the pager.
  bool m_page_screen_output;
 
  // TRUE means we write to the diary file.
  bool m_write_to_diary_file;
 
  bool m_really_flush_to_pager;
 
  bool m_flushing_output_to_pager;
 
  void start_external_pager ();
 
  void do_sync (const char *msg, int len, bool bypass_pager);
};
 
extern OCTINTERP_API std::ostream& __stdout__ ();
 
extern OCTINTERP_API std::ostream& __diary__ ();
 
OCTAVE_END_NAMESPACE(octave)
 
#define octave_stdout (octave::__stdout__ ())
 
#define octave_diary (octave::__diary__ ())
 
#endif