file-editor-tab.cc

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/*

Copyright (C) 2011-2018 Jacob Dawid

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/>.

*/

//! @file file-editor-tab.cc A single GUI file tab.
//!
//! This interfaces QsciScintilla with the rest of Octave.

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#if defined (HAVE_QSCINTILLA)

#if defined (HAVE_QSCI_QSCILEXEROCTAVE_H)
#  define HAVE_LEXER_OCTAVE 1
#  include <Qsci/qscilexeroctave.h>
#elif defined (HAVE_QSCI_QSCILEXERMATLAB_H)
#  define HAVE_LEXER_MATLAB 1
#  include <Qsci/qscilexermatlab.h>
#endif
#include <Qsci/qscilexercpp.h>
#include <Qsci/qscilexerbash.h>
#include <Qsci/qscilexerperl.h>
#include <Qsci/qscilexerbatch.h>
#include <Qsci/qscilexerdiff.h>
#include <Qsci/qsciprinter.h>
#include <QApplication>
#include <QFileDialog>
#include <QMessageBox>
#include <QTextStream>
#include <QVBoxLayout>
#include <QInputDialog>
#include <QPrintDialog>
#include <QDateTime>
#include <QDesktopServices>
#include <QTextCodec>
#include <QStyle>
#include <QTextBlock>
#include <QLabel>
#include <QCheckBox>
#include <QDialogButtonBox>
#include <QPushButton>

#include "resource-manager.h"
#include "file-editor-tab.h"
#include "file-editor.h"
#include "octave-txt-lexer.h"
#include "marker.h"

#include "file-ops.h"

#include "bp-table.h"
#include "call-stack.h"
#include "defaults.h"
#include "interpreter-private.h"
#include "interpreter.h"
#include "oct-map.h"
#include "octave-qt-link.h"
#include "ov-usr-fcn.h"
#include "symtab.h"
#include "unwind-prot.h"
#include "utils.h"
#include "version.h"
#include "octave-settings.h"

namespace octave
{
  bool file_editor_tab::_cancelled = false;

  //! A file_editor_tab object consists of a text area and three left margins.
  //! The first holds breakpoints, bookmarks, and the debug program counter.
  //! The second holds line numbers.  The third holds "fold" marks, to hide
  //! sections of text.

  // Make parent null for the file editor tab so that warning WindowModal
  // messages don't affect grandparents.
  file_editor_tab::file_editor_tab (const QString& directory_arg)
  {
    _lexer_apis = nullptr;
    _is_octave_file = true;
    _lines_changed = false;

    _ced = directory_arg;

    _file_name = "";
    _file_system_watcher.setObjectName ("_qt_autotest_force_engine_poller");

    _edit_area = new octave_qscintilla (this);
    _line = 0;
    _col  = 0;

    _bp_lines.clear ();      // start with empty lists of breakpoints
    _bp_conditions.clear ();
    m_bp_restore_count = 0;

    connect (_edit_area, SIGNAL (cursorPositionChanged (int, int)),
             this, SLOT (handle_cursor_moved (int,int)));

    connect (_edit_area, SIGNAL (SCN_CHARADDED (int)),
             this, SLOT (handle_char_added (int)));

    connect (_edit_area, SIGNAL (SCN_DOUBLECLICK (int, int, int)),
             this, SLOT (handle_double_click (int, int, int)));

    connect (_edit_area, SIGNAL (linesChanged ()),
             this, SLOT (handle_lines_changed ()));

    connect (_edit_area, SIGNAL (context_menu_edit_signal (const QString&)),
             this, SLOT (handle_context_menu_edit (const QString&)));

    // create statusbar for row/col indicator and eol mode
    _status_bar = new QStatusBar (this);

    // row- and col-indicator
    _row_indicator = new QLabel ("", this);
    QFontMetrics fm = _row_indicator->fontMetrics ();
    _row_indicator->setMinimumSize (4.5*fm.averageCharWidth (),0);
    QLabel *row_label = new QLabel (tr ("line:"), this);
    _col_indicator = new QLabel ("", this);
    _col_indicator->setMinimumSize (4*fm.averageCharWidth (),0);
    QLabel *col_label = new QLabel (tr ("col:"), this);
    _status_bar->addWidget (row_label, 0);
    _status_bar->addWidget (_row_indicator, 0);
    _status_bar->addWidget (col_label, 0);
    _status_bar->addWidget (_col_indicator, 0);

    // status bar: encoding
    QLabel *enc_label = new QLabel (tr ("encoding:"), this);
    _enc_indicator = new QLabel ("",this);
    _status_bar->addWidget (enc_label, 0);
    _status_bar->addWidget (_enc_indicator, 0);
    _status_bar->addWidget (new QLabel (" ", this), 0);

    // status bar: eol mode
    QLabel *eol_label = new QLabel (tr ("eol:"), this);
    _eol_indicator = new QLabel ("",this);
    _status_bar->addWidget (eol_label, 0);
    _status_bar->addWidget (_eol_indicator, 0);
    _status_bar->addWidget (new QLabel (" ", this), 0);

    // Leave the find dialog box out of memory until requested.
    _find_dialog = nullptr;
    _find_dialog_is_visible = false;

    // symbols
    _edit_area->setMarginType (1, QsciScintilla::SymbolMargin);
    _edit_area->setMarginSensitivity (1, true);
    _edit_area->markerDefine (QsciScintilla::RightTriangle, marker::bookmark);
    _edit_area->setMarkerBackgroundColor (QColor (0,0,232), marker::bookmark);
    _edit_area->markerDefine (QsciScintilla::Circle, marker::breakpoint);
    _edit_area->setMarkerBackgroundColor (QColor (192,0,0), marker::breakpoint);
    _edit_area->markerDefine (QsciScintilla::Circle, marker::cond_break);
    _edit_area->setMarkerBackgroundColor (QColor (255,127,0), marker::cond_break);
    _edit_area->markerDefine (QsciScintilla::RightArrow, marker::debugger_position);
    _edit_area->setMarkerBackgroundColor (QColor (255,255,0),
                                          marker::debugger_position);
    _edit_area->markerDefine (QsciScintilla::RightArrow,
                              marker::unsure_debugger_position);
    _edit_area->setMarkerBackgroundColor (QColor (192,192,192),
                                          marker::unsure_debugger_position);

    connect (_edit_area, SIGNAL (marginClicked (int, int,
                                                Qt::KeyboardModifiers)),
             this, SLOT (handle_margin_clicked (int, int,
                                                Qt::KeyboardModifiers)));

    connect (_edit_area, SIGNAL (context_menu_break_condition_signal (int)),
             this, SLOT (handle_context_menu_break_condition (int)));

    // line numbers
    _edit_area->setMarginsForegroundColor (QColor (96, 96, 96));
    _edit_area->setMarginsBackgroundColor (QColor (232, 232, 220));
    _edit_area->setMarginType (2, QsciScintilla::TextMargin);

    // other features
    _edit_area->setBraceMatching (QsciScintilla::StrictBraceMatch);
    _edit_area->setAutoIndent (true);
    _edit_area->setIndentationWidth (2);
    _edit_area->setIndentationsUseTabs (false);

    _edit_area->setUtf8 (true);

    // auto completion
    _edit_area->SendScintilla (QsciScintillaBase::SCI_AUTOCSETCANCELATSTART, false);

    QVBoxLayout *edit_area_layout = new QVBoxLayout ();
    edit_area_layout->addWidget (_edit_area);
    edit_area_layout->addWidget (_status_bar);
    edit_area_layout->setMargin (0);
    setLayout (edit_area_layout);

    // connect modified signal
    connect (_edit_area, SIGNAL (modificationChanged (bool)),
             this, SLOT (update_window_title (bool)));

    connect (_edit_area, SIGNAL (copyAvailable (bool)),
             this, SLOT (handle_copy_available (bool)));

    connect (&_file_system_watcher, SIGNAL (fileChanged (const QString&)),
             this, SLOT (file_has_changed (const QString&)));

    QSettings *settings = resource_manager::get_settings ();
    if (settings)
      notice_settings (settings, true);

    setFocusProxy (_edit_area);

    // encoding, not updated with the settings
#if defined (Q_OS_WIN32)
    _encoding = settings->value ("editor/default_encoding", "SYSTEM")
                .toString ();
#else
    _encoding = settings->value ("editor/default_encoding", "UTF-8")
                .toString ();
#endif
    _enc_indicator->setText (_encoding);
    // no changes in encoding yet
    _new_encoding = _encoding;
  }

  file_editor_tab::~file_editor_tab (void)
  {
    // Tell all connected markers to self-destruct.
    emit remove_all_breakpoints ();
    emit remove_all_positions ();

    // Destroy items attached to _edit_area.
    QsciLexer *lexer = _edit_area->lexer ();
    if (lexer)
      {
        delete lexer;
        _edit_area->setLexer (nullptr);
      }
    if (_find_dialog)
      {
        delete _find_dialog;
        _find_dialog = nullptr;
      }

    // Destroy _edit_area.
    delete _edit_area;
  }

  void file_editor_tab::set_encoding (const QString& new_encoding)
  {
    if (new_encoding.isEmpty ())
      return;

    _encoding = new_encoding;
    _enc_indicator->setText (_encoding);
    if (! _edit_area->text ().isEmpty ())
      set_modified (true);
  }

  void file_editor_tab::closeEvent (QCloseEvent *e)
  {
    _cancelled = false;  // prevent unwanted interaction of previous
    // exits of octave which were canceled by the user

    if (check_file_modified () == QMessageBox::Cancel)
      {
        // ignore close event if file is not saved and user cancels
        // closing this window
        e->ignore ();
      }
    else
      {
        e->accept ();
        emit tab_remove_request ();
      }
  }

  void file_editor_tab::set_current_directory (const QString& dir)
  {
    _ced = dir;
  }

  void file_editor_tab::handle_context_menu_edit (const QString& word_at_cursor)
  {
    // search for a subfunction in actual file (this is done at first because
    // octave finds this function before other with same name in the search path
    QRegExp rxfun1 ("^[\t ]*function[^=]+=[\t ]*"
                    + word_at_cursor + "[\t ]*\\([^\\)]*\\)[\t ]*$");
    QRegExp rxfun2 ("^[\t ]*function[\t ]+"
                    + word_at_cursor + "[\t ]*\\([^\\)]*\\)[\t ]*$");
    QRegExp rxfun3 ("^[\t ]*function[\t ]+"
                    + word_at_cursor + "[\t ]*$");
    QRegExp rxfun4 ("^[\t ]*function[^=]+=[\t ]*"
                    + word_at_cursor + "[\t ]*$");

    int pos_fct = -1;
    QStringList lines = _edit_area->text ().split ("\n");

    int line;
    for (line = 0; line < lines.count (); line++)
      {
        if ((pos_fct = rxfun1.indexIn (lines.at (line))) != -1)
          break;
        if ((pos_fct = rxfun2.indexIn (lines.at (line))) != -1)
          break;
        if ((pos_fct = rxfun3.indexIn (lines.at (line))) != -1)
          break;
        if ((pos_fct = rxfun4.indexIn (lines.at (line))) != -1)
          break;
      }

    if (pos_fct > -1)
      {
        // reg expr. found: it is an internal function
        _edit_area->setCursorPosition (line, pos_fct);
        _edit_area->SendScintilla (2232, line);     // SCI_ENSUREVISIBLE
        // SCI_VISIBLEFROMDOCLINE
        int vis_line = _edit_area->SendScintilla (2220, line);
        _edit_area->SendScintilla (2613, vis_line); // SCI_SETFIRSTVISIBLELINE
        return;
      }

    emit edit_mfile_request (word_at_cursor, _file_name, _ced, -1);
  }

  // If "dbstop if ..." selected from context menu, create a conditional
  // breakpoint.  The default condition is (a) the existing condition if there
  // is already a breakpoint (b) any selected text, or (c) empty
  void file_editor_tab::handle_context_menu_break_condition (int linenr)
  {
    // Ensure editor line numbers match Octave core's line numbers.
    // Give users the option to save modifications if necessary.
    if (! unchanged_or_saved ())
      return;

    QString cond;
    bp_info info (_file_name, linenr+1); // Get function name & dir from filename.

    // Search for previous condition.  FIXME: is there a more direct way?
    if (_edit_area->markersAtLine (linenr) & (1 << marker::cond_break))
      {
        emit report_marker_linenr (_bp_lines, _bp_conditions);
        for (int i = 0; i < _bp_lines.length (); i++)
          if (_bp_lines.value (i) == linenr)
            {
              cond = _bp_conditions.value (i);
              break;
            }
        _bp_lines.clear ();
        _bp_conditions.clear ();
      }

    // If text selected by the mouse, default to that instead
    // If both present, use the OR of them, to avoid accidental overwriting
    // FIXME: If both are present, show old condition unselected and
    //        the selection (in edit area) selected (in the dialog).
    if (_edit_area->hasSelectedText ())
      {
        if (cond == "")
          cond = _edit_area->selectedText ();
        else
          cond = '(' + cond + ") || (" + _edit_area->selectedText () + ')';
      }

    bool valid = false;
    std::string prompt = "dbstop if";
    bool ok;
    while (! valid)
      {
        QString new_condition
          = QInputDialog::getText (this, tr ("Breakpoint condition"),
                                   tr (prompt.c_str ()), QLineEdit::Normal, cond,
                                   &ok);
        if (ok)     // If cancel, don't change breakpoint condition.
          {
            try
              {
                // Suppress error messages on the console.
                unwind_protect frame;
                frame.protect_var (buffer_error_messages);
                buffer_error_messages++;

                octave::bp_table& bptab
                  = octave::__get_bp_table__ ("handle_context_menu_break_condition");

                bptab.condition_valid (new_condition.toStdString ());
                valid = true;
              }
            catch (const index_exception& e) { }
            catch (const execution_exception& e) { }
            catch (const interrupt_exception&)
              {
                ok = false;
                valid = true;
              }

            // In case we repeat, set new prompt.
            prompt = "ERROR: " + last_error_message () + "\n\ndbstop if";
            cond = new_condition;
          }
        else
          valid = true;
      }

    if (ok)       // If the user didn't cancel, actually set the breakpoint.
      {
        info.condition = cond.toStdString ();

        octave_link::post_event
          (this, &file_editor_tab::add_breakpoint_callback, info);
      }
  }

  void file_editor_tab::set_file_name (const QString& fileName)
  {
    // update tracked file if we really have a file on disk
    QStringList trackedFiles = _file_system_watcher.files ();
    if (! trackedFiles.isEmpty ())
      _file_system_watcher.removePath (_file_name);
    if (! fileName.isEmpty ())
      _file_system_watcher.addPath (fileName);

    // update lexer and file name variable if file name changes
    if (_file_name != fileName)
      {
        _file_name = fileName;
        update_lexer ();
      }

    // update the file editor with current editing directory
    emit editor_state_changed (_copy_available, _is_octave_file);

    // add the new file to the most-recently-used list
    emit mru_add_file (_file_name, _encoding);
  }

  // valid_file_name (file): checks whether "file" names a file.
  // By default, "file" is empty; then _file_name is checked
  bool file_editor_tab::valid_file_name (const QString& file)
  {
    if (file.isEmpty ())
      {
        if (_file_name.isEmpty ())
          return false;
        else
          return true;
      }

    return true;
  }

  // We cannot create a breakpoint when the file is modified
  // because the line number the editor is providing might
  // not match what Octave core is interpreting in the
  // file on disk.  This function gives the user the option
  // to save before creating the breakpoint.
  bool file_editor_tab::unchanged_or_saved (void)
  {
    bool retval = true;
    if (_edit_area->isModified ())
      {
        int ans = QMessageBox::question (nullptr, tr ("Octave Editor"),
                                         tr ("Cannot add breakpoint to modified file.\n"
                                             "Save and add breakpoint, or cancel?"),
                                         QMessageBox::Save | QMessageBox::Cancel, QMessageBox::Save);

        if (ans == QMessageBox::Save)
          save_file (_file_name, false);
        else
          retval = false;
      }

    return retval;
  }

  // Toggle a breakpoint at the editor_linenr or, if this was called by
  // a click with CTRL pressed, toggle a bookmark at that point.
  void file_editor_tab::handle_margin_clicked (int margin, int editor_linenr,
                                               Qt::KeyboardModifiers state)
  {
    if (margin == 1)
      {
        unsigned int markers_mask = _edit_area->markersAtLine (editor_linenr);

        if (state & Qt::ControlModifier)
          {
            if (markers_mask & (1 << marker::bookmark))
              _edit_area->markerDelete (editor_linenr, marker::bookmark);
            else
              _edit_area->markerAdd (editor_linenr, marker::bookmark);
          }
        else
          {
            if (markers_mask & ((1 << marker::breakpoint)
                                | (1 << marker::cond_break)))
              handle_request_remove_breakpoint (editor_linenr + 1);
            else
              {
                if (unchanged_or_saved ())
                  handle_request_add_breakpoint (editor_linenr + 1, "");
              }
          }
      }
  }


  void file_editor_tab::update_lexer (void)
  {
    // Create a new lexer
    QsciLexer *lexer = nullptr;

    _is_octave_file = false;

    // Find the required lexer from file extensions
    if (_file_name.endsWith (".m")
        || _file_name.endsWith ("octaverc"))
      {
#if defined (HAVE_LEXER_OCTAVE)
        lexer = new QsciLexerOctave ();
#elif defined (HAVE_LEXER_MATLAB)
        lexer = new QsciLexerMatlab ();
#else
        lexer = new octave_txt_lexer ();
#endif
        _is_octave_file = true;
      }

    if (! lexer)
      {
        if (_file_name.endsWith (".c")
            || _file_name.endsWith (".cc")
            || _file_name.endsWith (".cpp")
            || _file_name.endsWith (".cxx")
            || _file_name.endsWith (".c++")
            || _file_name.endsWith (".h")
            || _file_name.endsWith (".hh")
            || _file_name.endsWith (".hpp")
            || _file_name.endsWith (".h++"))
          {
            lexer = new QsciLexerCPP ();
          }
        else if (_file_name.endsWith (".pl"))
          {
            lexer = new QsciLexerPerl ();
          }
        else if (_file_name.endsWith (".bat"))
          {
            lexer = new QsciLexerBatch ();
          }
        else if (_file_name.endsWith (".diff"))
          {
            lexer = new QsciLexerDiff ();
          }
        else if (_file_name.endsWith (".sh"))
          {
            lexer = new QsciLexerBash ();
          }
        else if (! valid_file_name ())
          {
            // new, no yet named file: let us assume it is octave
#if defined (HAVE_LEXER_OCTAVE)
            lexer = new QsciLexerOctave ();
            _is_octave_file = true;
#elif defined (HAVE_LEXER_MATLAB)
            lexer = new QsciLexerMatlab ();
            _is_octave_file = true;
#else
            lexer = new octave_txt_lexer ();
#endif
          }
        else
          {
            // other or no extension
            lexer = new octave_txt_lexer ();
          }
      }

    // Get any existing lexer
    QsciLexer *old_lexer = _edit_area->lexer ();

    // If new file, no lexer, or lexer has changed,
    // delete old one and set the newly created as current lexer
    if (! old_lexer || ! valid_file_name ()
        || QString(old_lexer->lexer ()) != QString(lexer->lexer ()))
      {
        // Delete and set new lexer
        if (old_lexer)
          delete old_lexer;
        _edit_area->setLexer (lexer);

        // build information for auto completion (APIs)
        _lexer_apis = new QsciAPIs (lexer);

        // Get the settings for this new lexer
        update_lexer_settings ();
      }
    else
      {
        // Otherwise, delete the newly created lexer and
        // use the old, exisiting one
        if (lexer)
          delete lexer;
      }
  }


  // Update settings, which are lexer related and have to be updated
  // when a) the lexer changes or b) the settings have changed.
  void file_editor_tab::update_lexer_settings (void)
  {
    QsciLexer *lexer = _edit_area->lexer ();

    QSettings *settings = resource_manager::get_settings ();

    if (_lexer_apis)
      {
        _lexer_apis->cancelPreparation ();  // stop preparing if apis exists

        bool update_apis = false;  // flag, whether update of apis files

        // get path to prepared api info
#if defined (HAVE_QSTANDARDPATHS)
        QString prep_apis_path
          = QStandardPaths::writableLocation (QStandardPaths::HomeLocation)
            + "/.config/octave/" + QString (OCTAVE_VERSION) + "/qsci/";
#else
        QString prep_apis_path
          = QDesktopServices::storageLocation (QDesktopServices::HomeLocation)
            + "/.config/octave/" + QString (OCTAVE_VERSION) + "/qsci/";
#endif

        // get settings which infos are used for octave
        bool octave_builtins = settings->value (
                                 "editor/codeCompletion_octave_builtins", true).toBool ();
        bool octave_functions = settings->value (
                                  "editor/codeCompletion_octave_functions", true).toBool ();

        if (_is_octave_file)
          {
            // Keywords and Builtins do not change, these informations can be
            // stored in prepared form in a file. Information on function are
            // changing frequently, then if functions should also be auto-
            // completed, the date of any existing file is checked.

            // Keywords are always used
            _prep_apis_file = prep_apis_path + lexer->lexer () + "_k";

            // Buitlins are only used if the user settings say so
            if (octave_builtins)
              _prep_apis_file += 'b';

            if (octave_functions)
              _prep_apis_file += 'f';

            _prep_apis_file += ".pap"; // final name of apis file

            // check whether the APIs info needs to be prepared and saved
            QFileInfo apis_file = QFileInfo (_prep_apis_file);
            // flag whether apis file needs update
            update_apis = ! apis_file.exists ();

            if (octave_functions)
              {
                // Functions may change frequently. Update the apis data
                // if the file is older than a few minutes preventing from
                // re-preparing data when the user opens several files.
                QDateTime apis_time = apis_file.lastModified ();
                if (QDateTime::currentDateTime () > apis_time.addSecs (180))
                  update_apis = true;
              }

          }
        else  // no octave file, just add extension
          {

            _prep_apis_file = prep_apis_path + lexer->lexer () + ".pap";

          }

        if (update_apis || ! _lexer_apis->loadPrepared (_prep_apis_file))
          {
            // either we have decided to update the apis file or
            // no prepared info was loaded, prepare and save if possible

            // create raw apis info
            QString keyword;
            QStringList keyword_list;
            int i,j;

            if (_is_octave_file)
              {
                // octave: get keywords from internal informations depending on
                //         user preferences

                // keywords are always used
                add_octave_apis (Fiskeyword ());            // add new entries

                interpreter& interp
                  = __get_interpreter__ (
                      "file_editor_tab::update_lexer_settings");

                if (octave_builtins)
                  add_octave_apis (F__builtins__ (interp));       // add new entries

                if (octave_functions)
                  add_octave_apis (F__list_functions__ (interp)); // add new entries

              }
            else
              {

                _prep_apis_file = prep_apis_path + lexer->lexer () + ".pap";

                for (i=1; i<=3; i++) // test the first 5 keyword sets
                  {
                    keyword = QString (lexer->keywords (i));           // get list
                    keyword_list = keyword.split (QRegExp (R"(\s+)")); // split
                    for (j = 0; j < keyword_list.size (); j++)         // add to API
                      _lexer_apis->add (keyword_list.at (j));
                  }
              }

            // disconnect slot for saving prepared info if already connected
            disconnect (_lexer_apis, SIGNAL (apiPreparationFinished ()), nullptr, nullptr);
            // check whether path for prepared info exists or can be created
            if (QDir ("/").mkpath (prep_apis_path))
              {
                // path exists, apis info can be saved there
                connect (_lexer_apis, SIGNAL (apiPreparationFinished ()),
                         this, SLOT (save_apis_info ()));
              }

            _lexer_apis->prepare ();  // prepare apis info

          }
      }

    lexer->readSettings (*settings);

    _edit_area->setCaretForegroundColor (lexer->color (0));
    _edit_area->setIndentationGuidesForegroundColor (lexer->color (0));

    // set some colors depending on selected background color of the lexer
    QColor bg = lexer->paper (0);
    QColor fg = lexer->color (0);

    int bh, bs, bv, fh, fs, fv, h, s, v;
    bg.getHsv (&bh,&bs,&bv);
    fg.getHsv (&fh,&fs,&fv);

    // margin colors
    h = bh;
    s = bs/2;
    v = bv + (fv - bv)/5;

    bg.setHsv (h,s,v);
    _edit_area->setEdgeColor (bg);

    v = bv + (fv - bv)/8;
    bg.setHsv (h,s,v);
    v = bv + (fv - bv)/4;
    fg.setHsv (h,s,v);

    _edit_area->setMarkerForegroundColor (lexer->color (0));
    _edit_area->setMarginsForegroundColor (lexer->color (0));
    _edit_area->setMarginsBackgroundColor (bg);
    _edit_area->setFoldMarginColors (bg,fg);

    // color indicator for highlighting all occurrences:
    // applications highlight color with more transparency
    QColor hg = QApplication::palette ().color (QPalette::Highlight);
    _edit_area->set_selection_marker_color (hg);

    // fix line number width with respect to the font size of the lexer and
    // set the line numbers font depending on the lexers font
    if (settings->value ("editor/showLineNumbers", true).toBool ())
      {
        // Line numbers width
        auto_margin_width ();

        // Line numbers font
        QFont line_numbers_font = lexer->defaultFont ();
        int font_size = line_numbers_font.pointSize ();
        font_size = font_size
                    + settings->value ("editor/line_numbers_size", 0).toInt ();
        if (font_size < 4)
          font_size = 4;
        line_numbers_font.setPointSize (font_size);

        _edit_area->setMarginsFont (line_numbers_font);
      }
    else
      _edit_area->setMarginWidth (2,0);
  }


  // function for adding entries to the octave lexer's APIs
  void file_editor_tab::add_octave_apis (octave_value_list key_ovl)
  {
    octave_value keys = key_ovl(0);
    Cell key_list = keys.cell_value ();

    for (int idx = 0; idx < key_list.numel (); idx++)
      _lexer_apis->add (QString (key_list.elem (idx).string_value ().data ()));
  }

  void file_editor_tab::save_apis_info (void)
  {
    _lexer_apis->savePrepared (_prep_apis_file);
  }

  // slot for fetab_set_focus: sets the focus to the current edit area
  void file_editor_tab::set_focus (const QWidget *ID)
  {
    if (ID != this)
      return;
    _edit_area->setFocus ();
  }

  void file_editor_tab::context_help (const QWidget *ID, bool doc)
  {
    if (ID != this)
      return;

    _edit_area->context_help_doc (doc);
  }

  void file_editor_tab::context_edit (const QWidget *ID)
  {
    if (ID != this)
      return;

    _edit_area->context_edit ();
  }

  void file_editor_tab::check_modified_file (void)
  {
    if (_cancelled)
      return;

    if (check_file_modified () == QMessageBox::Cancel)
      _cancelled = true;
  }

  void file_editor_tab::save_file (const QWidget *ID)
  {
    if (ID != this)
      return;

    save_file (_file_name);
  }

  void file_editor_tab::save_file (const QWidget *ID, const QString& fileName,
                                   bool remove_on_success)
  {
    if (ID != this)
      return;

    save_file (fileName, remove_on_success);
  }

  void file_editor_tab::save_file_as (const QWidget *ID)
  {
    if (ID != this)
      return;

    save_file_as ();
  }

  void file_editor_tab::print_file (const QWidget *ID)
  {
    if (ID != this)
      return;

    QsciPrinter *printer = new QsciPrinter (QPrinter::HighResolution);

    QPrintDialog printDlg (printer, this);

    if (printDlg.exec () == QDialog::Accepted)
      printer->printRange (_edit_area);

    delete printer;
  }

  void file_editor_tab::run_file (const QWidget *ID)
  {
    if (ID != this)
      return;

    if (_edit_area->isModified () | ! valid_file_name ())
      {
        save_file (_file_name);  // save file dialog
        if (! valid_file_name ())
          return;   // still invalid filename: "save as" was cancelled
      }

    QFileInfo info (_file_name);
    emit run_file_signal (info);
  }

  void file_editor_tab::context_run (const QWidget *ID)
  {
    if (ID != this)
      return;

    _edit_area->context_run ();
  }

  void file_editor_tab::toggle_bookmark (const QWidget *ID)
  {
    if (ID != this)
      return;

    int line, cur;
    _edit_area->getCursorPosition (&line, &cur);

    if (_edit_area->markersAtLine (line) & (1 << marker::bookmark))
      _edit_area->markerDelete (line, marker::bookmark);
    else
      _edit_area->markerAdd (line, marker::bookmark);
  }

  // Move the text cursor to the closest bookmark
  // after the current line.
  void file_editor_tab::next_bookmark (const QWidget *ID)
  {
    if (ID != this)
      return;

    int line, cur;
    _edit_area->getCursorPosition (&line, &cur);

    line++; // Find bookmark strictly after the current line.

    int nextline = _edit_area->markerFindNext (line, (1 << marker::bookmark));

    // Wrap.
    if (nextline == -1)
      nextline = _edit_area->markerFindNext (1, (1 << marker::bookmark));

    _edit_area->setCursorPosition (nextline, 0);
  }

  // Move the text cursor to the closest bookmark
  // before the current line.
  void file_editor_tab::previous_bookmark (const QWidget *ID)
  {
    if (ID != this)
      return;

    int line, cur;
    _edit_area->getCursorPosition (&line, &cur);

    line--; // Find bookmark strictly before the current line.

    int prevline = _edit_area->markerFindPrevious (line, (1 << marker::bookmark));

    // Wrap.  Should use the last line of the file, not 1<<15
    if (prevline == -1)
      prevline = _edit_area->markerFindPrevious (_edit_area->lines (),
                                                 (1 << marker::bookmark));

    _edit_area->setCursorPosition (prevline, 0);
  }

  void file_editor_tab::remove_bookmark (const QWidget *ID)
  {
    if (ID != this)
      return;

    _edit_area->markerDeleteAll (marker::bookmark);
  }

  void file_editor_tab::add_breakpoint_callback (const bp_info& info)
  {
    bp_table::intmap line_info;
    line_info[0] = info.line;

    if (octave_qt_link::file_in_path (info.file, info.dir))
      {
        octave::bp_table& bptab
          = octave::__get_bp_table__ ("octave_qt_link::file_in_path");

        bptab.add_breakpoint (info.function_name, line_info, info.condition);
      }
  }

  void file_editor_tab::remove_breakpoint_callback (const bp_info& info)
  {
    bp_table::intmap line_info;
    line_info[0] = info.line;

    if (octave_qt_link::file_in_path (info.file, info.dir))
      {
        octave::bp_table& bptab
          = octave::__get_bp_table__ ("remove_breakpoint_callback");

        bptab.remove_breakpoint (info.function_name, line_info);
      }
  }

  void file_editor_tab::remove_all_breakpoints_callback (const bp_info& info)
  {
    if (octave_qt_link::file_in_path (info.file, info.dir))
      {
        octave::bp_table& bptab
          = octave::__get_bp_table__ ("remove_all_breakpoints_callback");

        bptab.remove_all_breakpoints_in_file (info.function_name, true);
      }
  }

  file_editor_tab::bp_info::bp_info (const QString& fname, int l,
                                     const QString& cond)
    : line (l), file (fname.toStdString ()), condition (cond.toStdString ())
  {
    QFileInfo file_info (fname);

    QString q_dir = file_info.absolutePath ();
    QString q_function_name = file_info.fileName ();

    // We have to cut off the suffix, because octave appends it.
    q_function_name.chop (file_info.suffix ().length () + 1);

    dir = q_dir.toStdString ();
    function_name = q_function_name.toStdString ();

    // Is the last component of DIR @foo?  If so, strip it and prepend it
    // to the name of the function.

    size_t pos = dir.rfind (sys::file_ops::dir_sep_chars ());

    if (pos != std::string::npos && pos < dir.length () - 1)
      {
        if (dir[pos+1] == '@')
          {
            function_name = sys::file_ops::concat (dir.substr (pos+1), function_name);

            dir = dir.substr (0, pos);
          }
      }
  }

  void file_editor_tab::handle_request_add_breakpoint (int line,
                                                       const QString& condition)
  {
    bp_info info (_file_name, line, condition);

    octave_link::post_event
      (this, &file_editor_tab::add_breakpoint_callback, info);
  }

  void file_editor_tab::handle_request_remove_breakpoint (int line)
  {
    bp_info info (_file_name, line);

    octave_link::post_event
      (this, &file_editor_tab::remove_breakpoint_callback, info);
  }

  void file_editor_tab::toggle_breakpoint (const QWidget *ID)
  {
    if (ID != this)
      return;

    int editor_linenr, cur;
    _edit_area->getCursorPosition (&editor_linenr, &cur);

    if (_edit_area->markersAtLine (editor_linenr) & (1 << marker::breakpoint))
      request_remove_breakpoint_via_editor_linenr (editor_linenr);
    else
      {
        if (unchanged_or_saved ())
          handle_request_add_breakpoint (editor_linenr + 1, "");
      }
  }

  // Move the text cursor to the closest breakpoint (conditional or unconditional)
  // after the current line.
  void file_editor_tab::next_breakpoint (const QWidget *ID)
  {
    if (ID != this)
      return;

    int line, cur;
    _edit_area->getCursorPosition (&line, &cur);

    line++; // Find breakpoint strictly after the current line.

    int nextline = _edit_area->markerFindNext (line, (1 << marker::breakpoint));
    int nextcond = _edit_area->markerFindNext (line, (1 << marker::cond_break));

    // Check if the next conditional breakpoint is before next unconditional one.
    if (nextcond != -1 && (nextcond < nextline || nextline == -1))
      nextline = nextcond;

    _edit_area->setCursorPosition (nextline, 0);
  }

  // Move the text cursor to the closest breakpoint (conditional or unconditional)
  // before the current line.
  void file_editor_tab::previous_breakpoint (const QWidget *ID)
  {
    if (ID != this)
      return;

    int line, cur, prevline, prevcond;
    _edit_area->getCursorPosition (&line, &cur);

    line--; // Find breakpoint strictly before the current line.

    prevline = _edit_area->markerFindPrevious (line, (1 << marker::breakpoint));
    prevcond = _edit_area->markerFindPrevious (line, (1 << marker::cond_break));

    // Check if the prev conditional breakpoint is closer than the unconditional.
    if (prevcond != -1 && prevcond > prevline)
      prevline = prevcond;

    _edit_area->setCursorPosition (prevline, 0);
  }

  void file_editor_tab::remove_all_breakpoints (const QWidget *ID)
  {
    if (ID != this)
      return;

    bp_info info (_file_name);

    octave_link::post_event
      (this, &file_editor_tab::remove_all_breakpoints_callback, info);
  }

  void file_editor_tab::scintilla_command (const QWidget *ID, unsigned int sci_msg)
  {
    if (ID != this)
      return;

    _edit_area->SendScintilla (sci_msg);
  }

  void file_editor_tab::comment_selected_text (const QWidget *ID, bool input_str)
  {
    if (ID != this)
      return;

    do_comment_selected_text (true, input_str);
  }

  void file_editor_tab::uncomment_selected_text (const QWidget *ID)
  {
    if (ID != this)
      return;

    do_comment_selected_text (false);
  }

  void file_editor_tab::indent_selected_text (const QWidget *ID)
  {
    if (ID != this)
      return;

    do_indent_selected_text (true);
  }

  void file_editor_tab::unindent_selected_text (const QWidget *ID)
  {
    if (ID != this)
      return;

    do_indent_selected_text (false);
  }

  void file_editor_tab::smart_indent_line_or_selected_text (const QWidget *ID)
  {
    if (ID != this)
      return;

    do_smart_indent_line_or_selected_text ();
  }

  void file_editor_tab::convert_eol (const QWidget *ID,
                                     QsciScintilla::EolMode eol_mode)
  {
    if (ID != this)
      return;

    _edit_area->convertEols (eol_mode);
    _edit_area->setEolMode (eol_mode);
    update_eol_indicator ();
  }

  void file_editor_tab::zoom_in (const QWidget *ID)
  {
    if (ID != this)
      return;

    _edit_area->zoomIn (1);
    auto_margin_width ();
  }

  void file_editor_tab::zoom_out (const QWidget *ID)
  {
    if (ID != this)
      return;

    _edit_area->zoomOut (1);
    auto_margin_width ();
  }

  void file_editor_tab::zoom_normal (const QWidget *ID)
  {
    if (ID != this)
      return;

    _edit_area->zoomTo (0);
    auto_margin_width ();
  }

  void file_editor_tab::handle_find_dialog_finished (int)
  {
    // Find dialog is going to hide.  Save location of window for
    // when it is reshown.
    _find_dialog_geometry = _find_dialog->geometry ();
    _find_dialog_is_visible = false;
  }

  void file_editor_tab::find (const QWidget *ID, QList<QAction *> fetab_actions)
  {
    if (ID != this)
      return;

    // The find_dialog feature doesn't need a slot for return info.
    // Rather than Qt::DeleteOnClose, let the find feature hang about
    // in case it contains useful information like previous searches
    // and so on.  Perhaps one find dialog for the whole editor is
    // better, but individual find dialogs has the nice feature of
    // retaining position per file editor tabs, which can be undocked.

    if (! _find_dialog)
      {
        _find_dialog = new find_dialog (_edit_area,
                                        fetab_actions.mid (0,2),
                                        qobject_cast<QWidget *> (sender ()));
        connect (_find_dialog, SIGNAL (finished (int)),
                 this, SLOT (handle_find_dialog_finished (int)));

        connect (this, SIGNAL (request_find_next ()),
                 _find_dialog, SLOT (find_next ()));

        connect (this, SIGNAL (request_find_previous ()),
                 _find_dialog, SLOT (find_prev ()));

        _find_dialog->setWindowModality (Qt::NonModal);
        _find_dialog_geometry = _find_dialog->geometry ();
      }
    else if (! _find_dialog->isVisible ())
      {
        _find_dialog->setGeometry (_find_dialog_geometry);
        QPoint p = _find_dialog->pos ();
        _find_dialog->move (p.x ()+10, p.y ()+10);
      }

    _find_dialog->show ();
    _find_dialog_is_visible = true;
    _find_dialog->activateWindow ();
    _find_dialog->init_search_text ();

  }

  void file_editor_tab::find_next (const QWidget *ID)
  {
    if (ID == this)
      emit request_find_next ();
  }

  void file_editor_tab::find_previous (const QWidget *ID)
  {
    if (ID == this)
      emit request_find_previous ();
  }

  void file_editor_tab::goto_line (const QWidget *ID, int line)
  {
    if (ID != this)
      return;

    if (m_bp_restore_count > 0)
      {
        // This goto-line request is invoked by restoring a breakpoint during
        // saving the file, thus, do not go to the related line
        m_bp_restore_count--;
        return;
      }

    if (line <= 0)  // ask for desired line
      {
        bool ok = false;
        int index;
        _edit_area->getCursorPosition (&line, &index);
        line = QInputDialog::getInt (_edit_area, tr ("Goto line"),
                                     tr ("Line number"), line+1, 1,
                                     _edit_area->lines (), 1, &ok);
        if (ok)
          _edit_area->setCursorPosition (line-1, 0);
      }
    else  // go to given line without dialog
      _edit_area->setCursorPosition (line-1, 0);

    center_current_line (false);  // only center line if at top or bottom
  }

  void file_editor_tab::move_match_brace (const QWidget *ID, bool select)
  {
    if (ID != this)
      return;

    if (select)
      _edit_area->selectToMatchingBrace ();
    else
      _edit_area->moveToMatchingBrace ();
  }

  void file_editor_tab::show_auto_completion (const QWidget *ID)
  {
    if (ID != this)
      return;

    QsciScintilla::AutoCompletionSource s = _edit_area->autoCompletionSource ();
    switch (s)
      {
      case QsciScintilla::AcsAll:
        _edit_area->autoCompleteFromAll ();
        break;

      case QsciScintilla::AcsAPIs:
        _edit_area->autoCompleteFromAPIs ();
        break;

      case QsciScintilla::AcsDocument:
        _edit_area->autoCompleteFromDocument ();
        break;

      case QsciScintilla::AcsNone:
        break;
      }
  }

  void file_editor_tab::do_indent_selected_text (bool indent)
  {
    // FIXME:
    _edit_area->beginUndoAction ();

    if (_edit_area->hasSelectedText ())
      {
        int lineFrom, lineTo, colFrom, colTo;
        _edit_area->getSelection (&lineFrom, &colFrom, &lineTo, &colTo);

        if (colTo == 0)  // the beginning of last line is not selected
          lineTo--;        // stop at line above

        for (int i = lineFrom; i <= lineTo; i++)
          {
            if (indent)
              _edit_area->indent (i);
            else
              _edit_area->unindent (i);
          }
        //set selection on (un)indented section
        _edit_area->setSelection (lineFrom, 0, lineTo,
                                  _edit_area->text (lineTo).length ()-1);
      }
    else
      {
        int cpline, col;
        _edit_area->getCursorPosition (&cpline, &col);
        if (indent)
          _edit_area->indent (cpline);
        else
          _edit_area->unindent (cpline);
      }

    _edit_area->endUndoAction ();
  }

  void file_editor_tab::do_smart_indent_line_or_selected_text (void)
  {
    _edit_area->beginUndoAction ();

    int lineFrom, lineTo;

    if (_edit_area->hasSelectedText ())
      {
        int colFrom, colTo;
        _edit_area->getSelection (&lineFrom, &colFrom, &lineTo, &colTo);

        if (colTo == 0)  // the beginning of last line is not selected
          lineTo--;        // stop at line above
      }
    else
      {
        int col;
        _edit_area->getCursorPosition (&lineFrom, &col);

        lineTo = lineFrom;
      }

    _edit_area->smart_indent_line_or_selected_text (lineFrom, lineTo);

    _edit_area->endUndoAction ();
  }

  void file_editor_tab::do_comment_selected_text (bool comment, bool input_str)
  {
    QRegExp rxc;
    QString ws = "^([ \\t]*)";
    QStringList comment_str = _edit_area->comment_string (comment);
    QString used_comment_str = comment_str.at (0);

    if (comment)
      {
        if (input_str)
          {
            bool ok;
            QSettings *settings = resource_manager::get_settings ();

            used_comment_str = QInputDialog::getText (
                                 this, tr ("Comment selected text"),
                                 tr ("Comment string to use:\n"), QLineEdit::Normal,
                                 settings->value (oct_last_comment_str, comment_str.at (0)).toString (),
                                 &ok);

            if ((! ok) || used_comment_str.isEmpty ())
              return;  // No input, do nothing
            else
              settings->setValue (oct_last_comment_str, used_comment_str);  // Store last
          }
      }
    else
      {
        // Uncommenting (several strings possible)

        // Sort strings according their length
        QStringList comment_str_sorted (comment_str.at (0));
        bool inserted;

        for (int i = 1; i < comment_str.length (); i++)
          {
            inserted = false;
            for (int j = 0; j < comment_str_sorted.length (); j++)
              {
                if (comment_str.at (i).length () > comment_str_sorted.at (j).length ())
                  {
                    comment_str_sorted.insert (j, comment_str.at (i));
                    inserted = true;
                    break;
                  }
              }
            if (! inserted)
              comment_str_sorted << comment_str.at (i);
          }

        // Create regular expression
        QString regexp;
        for (int i = 0; i < comment_str_sorted.length (); i++)
          {
            if (i > 0)
              regexp = regexp + QString ("|");
            regexp = regexp + comment_str_sorted.at (i);
          }
        rxc = QRegExp (ws + "(" + regexp + ")");
      }

    // Do the commenting/uncommenting
    int len = 0, lenc = 0;
    _edit_area->beginUndoAction ();

    if (_edit_area->hasSelectedText ())
      {
        int lineFrom, lineTo, colFrom, colTo;
        int change_col_from = 1;
        int change_col_to = 1;
        bool removed;

        _edit_area->getSelection (&lineFrom, &colFrom, &lineTo, &colTo);

        if (colTo == 0)  // the beginning of last line is not selected
          lineTo--;        // stop at line above

        for (int i = lineFrom; i <= lineTo; i++)
          {
            if (comment)
              {
                _edit_area->insertAt (used_comment_str, i, 0);
              }
            else
              {
                QString line (_edit_area->text (i));
                if ((removed = line.contains (rxc)))
                  {
                    len = rxc.matchedLength ();   // complete length
                    QString matched_text = rxc.capturedTexts ().at (0);
                    lenc = matched_text.remove (QRegExp (ws)).length ();  // only comment string
                    _edit_area->setSelection (i, len-lenc, i, len);
                    _edit_area->removeSelectedText ();
                  }

                // handle case, where the selection remains unchanged
                if (i == lineFrom && (colFrom < len-lenc || ! removed))
                  change_col_from = 0;  // do not change start of selection
                if (i == lineTo && (colTo < len-lenc || ! removed))
                  change_col_to = 0;    // do not change end of selection
              }
          }

        // update the selection area
        if (comment)
          {
            colFrom = colFrom + lenc;   // shift start position by comment length
            if (colTo > 0)
              colTo = colTo + lenc;     // shift end position by comment length
            else
              lineTo++;                 // colTo == 0 , fully select previous line
          }
        else
          {
            if (colTo == 0)
              lineTo++;                 // colTo == 0 , fully select previous line
            colFrom = colFrom - change_col_from*lenc;
            colTo = colTo - change_col_to*lenc;
          }

        // set updated selection area
        _edit_area->setSelection (lineFrom, colFrom, lineTo, colTo);
      }
    else
      {
        int cpline, col;
        _edit_area->getCursorPosition (&cpline, &col);
        if (comment)
          _edit_area->insertAt (used_comment_str, cpline, 0);
        else
          {
            QString line (_edit_area->text (cpline));
            if (line.contains (rxc))
              {
                len = rxc.matchedLength ();   // complete length
                QString matched_text = rxc.capturedTexts ().at (0);
                lenc = matched_text.remove (QRegExp (ws)).length ();  // only comment string
                _edit_area->setSelection (cpline, len-lenc, cpline, len);
                _edit_area->removeSelectedText ();
              }
          }
      }
    _edit_area->endUndoAction ();
  }

  void file_editor_tab::update_window_title (bool modified)
  {
    QString title ("");
    QString tooltip ("");

    if (! valid_file_name ())
      title = tr ("<unnamed>");
    else
      {
        if (_long_title)
          title = _file_name;
        else
          {
            QFileInfo file (_file_name);
            title = file.fileName ();
            tooltip = _file_name;
          }
      }

    if (modified)
      emit file_name_changed (title.prepend ("* "), tooltip);
    else
      emit file_name_changed (title, tooltip);
  }

  void file_editor_tab::handle_copy_available (bool enableCopy)
  {
    _copy_available = enableCopy;
    emit editor_state_changed (_copy_available, _is_octave_file);
  }

  // show_dialog: shows a modal or non modal dialog depending on input arg
  void file_editor_tab::show_dialog (QDialog *dlg, bool modal)
  {
    dlg->setAttribute (Qt::WA_DeleteOnClose);
    if (modal)
      dlg->exec ();
    else
      {
        dlg->setWindowModality (Qt::NonModal);
        dlg->show ();
      }
  }

  int file_editor_tab::check_file_modified (void)
  {
    int decision = QMessageBox::Yes;
    if (_edit_area->isModified ())
      {
        // File is modified but not saved, ask user what to do.  The file
        // editor tab can't be made parent because it may be deleted depending
        // upon the response.  Instead, change the _edit_area to read only.
        QMessageBox::StandardButtons buttons = QMessageBox::Save |
                                               QMessageBox::Discard |
                                               QMessageBox::Cancel;

        // For now, just a warning message about closing a tab that has been
        // modified seems sufficient.  Exit-condition-specific messages could
        // be achieved by making 'available_actions' a function input string.
        QString available_actions =
          tr ("Do you want to cancel closing, save or discard the changes?");

        QString file;
        if (valid_file_name ())
          file = _file_name;
        else
          file = tr ("<unnamed>");

        QMessageBox *msgBox
          = new QMessageBox (QMessageBox::Warning, tr ("Octave Editor"),
                             tr ("The file\n\n"
                                 "  %1\n\n"
                                 "is about to be closed but has been modified.  "
                                 "%2").
                             arg (file). arg (available_actions),
                             buttons, qobject_cast<QWidget *> (parent ()));

        msgBox->setDefaultButton (QMessageBox::Save);
        _edit_area->setReadOnly (true);
        connect (msgBox, SIGNAL (finished (int)),
                 this, SLOT (handle_file_modified_answer (int)));

        show_dialog (msgBox, true);

        if (_cancelled)
          return QMessageBox::Cancel;
        else
          return decision;
      }
    else
      {
        // Nothing was modified.  Leave tab present in case user
        // decides to cancel some point further along.
      }

    return decision;
  }

  void file_editor_tab::handle_file_modified_answer (int decision)
  {
    if (decision == QMessageBox::Save)
      {
        // Save file, but do not remove from editor.
        save_file (_file_name, false, false);
      }
    else if (decision == QMessageBox::Discard)
      {
        // User doesn't want to save, leave tab and remove subsequently.
      }
    else
      {
        // User canceled, allow editing again.
        _edit_area->setReadOnly (false);
        _cancelled = true;
      }
  }

  void file_editor_tab::set_modified (bool modified)
  {
    _edit_area->setModified (modified);
  }

  void file_editor_tab::recover_from_exit (void)
  {
    // reset the possibly still existing read only state
    _edit_area->setReadOnly (false);

    // if we are in this slot and the list of breakpoint is not empty,
    // then this tab was saved during an exit of the applications (not
    // restoring the breakpoints and not emptying the list) and the user
    // canceled this closing late on.
    check_restore_breakpoints ();
  }

  void file_editor_tab::check_restore_breakpoints (void)
  {
    if (! _bp_lines.isEmpty ())
      {
        // At least one breakpoint is present.
        // Get rid of breakpoints at old (now possibly invalid) linenumbers
        remove_all_breakpoints (this);

        // and set breakpoints at the new linenumbers
        m_bp_restore_count = _bp_lines.length ();
        for (int i = 0; i < _bp_lines.length (); i++)
          handle_request_add_breakpoint (_bp_lines.value (i) + 1,
                                         _bp_conditions.value (i));

        // Keep the list of breakpoints empty, except after explicit requests.
        _bp_lines.clear ();
        _bp_conditions.clear ();
      }
  }

  QString file_editor_tab::load_file (const QString& fileName)
  {
    // get the absolute path
    QFileInfo file_info = QFileInfo (fileName);
    QString file_to_load;
    if (file_info.exists ())
      file_to_load = file_info.canonicalFilePath ();
    else
      file_to_load = fileName;
    QFile file (file_to_load);
    if (! file.open (QFile::ReadOnly))
      return file.errorString ();

    // read the file
    QTextStream in (&file);
    // set the desired codec
    QTextCodec *codec = QTextCodec::codecForName (_encoding.toLatin1 ());
    in.setCodec (codec);

    QApplication::setOverrideCursor (Qt::WaitCursor);
    _edit_area->setText (in.readAll ());
    _edit_area->setEolMode (detect_eol_mode ());
    QApplication::restoreOverrideCursor ();

    _copy_available = false;     // no selection yet available
    set_file_name (file_to_load);
    update_window_title (false); // window title (no modification)
    _edit_area->setModified (false); // loaded file is not modified yet

    update_eol_indicator ();

    // FIXME: (BREAKPOINTS) At this point it would be nice to put any set
    // breakpoints on the margin.  In order to do this, somehow the
    // "dbstatus" command needs to be accessed.  All it would require is a
    // routine that does "res = feval ("dbstatus") and signals that result
    // to some slot.
    //
    // See patch #8016 for a general way to get Octave results from
    // commands processed in the background.

    /*
      connect (octave_link, SIGNAL (fileSelected (QObject *, const QString&, const octave_value_list&)),
      this, SLOT (handle_feval_result (QObject *, const QString&, const octave_value_list&)));
      connect (this, SIGNAL (evaluate_octave_command (const QString&)),
      octave_link, SLOT (queue_octave_command (const QString&)));

      emit evaluate_octave_command ("dbstatus");
    */

    return QString ();
  }

  QsciScintilla::EolMode file_editor_tab::detect_eol_mode (void)
  {
    QByteArray text = _edit_area->text ().toLatin1 ();

    QByteArray eol_lf = QByteArray (1,0x0a);
    QByteArray eol_cr = QByteArray (1,0x0d);
    QByteArray eol_crlf = eol_cr;
    eol_crlf.append (eol_lf);

    int count_crlf = text.count (eol_crlf);
    int count_lf = text.count (eol_lf) - count_crlf;  // isolated lf
    int count_cr = text.count (eol_cr) - count_crlf;  // isolated cr;

    // get default from OS or from settings
#if defined (Q_OS_WIN32)
    int os_eol_mode = QsciScintilla::EolWindows;
#elif defined (Q_OS_MAC)
    int os_eol_mode = QsciScintilla::EolMac;
#else
    int os_eol_mode = QsciScintilla::EolUnix;
#endif
    QSettings *settings = resource_manager::get_settings ();
    QsciScintilla::EolMode eol_mode = static_cast<QsciScintilla::EolMode> (
                                        settings->value ("editor/default_eol_mode",os_eol_mode).toInt ());

    int count_max = 0;

    if (count_crlf > count_max)
      {
        eol_mode = QsciScintilla::EolWindows;
        count_max = count_crlf;
      }
    if (count_lf > count_max)
      {
        eol_mode = QsciScintilla::EolUnix;
        count_max = count_lf;
      }
    if (count_cr > count_max)
      {
        eol_mode = QsciScintilla::EolMac;
        count_max = count_cr;
      }

    return eol_mode;
  }

  void file_editor_tab::update_eol_indicator (void)
  {
    switch (_edit_area->eolMode ())
      {
      case QsciScintilla::EolWindows:
        _eol_indicator->setText ("CRLF");
        break;
      case QsciScintilla::EolMac:
        _eol_indicator->setText ("CR");
        break;
      case QsciScintilla::EolUnix:
        _eol_indicator->setText ("LF");
        break;
      }
  }

  // FIXME: See patch #8016 for a general way to get Octave results from
  // commands processed in the background, e.g., dbstatus.
  void file_editor_tab::handle_octave_result (QObject *requester,
                                              QString& command,
                                              octave_value_list&)
  {
    // Check if this object initiated the command.
    if (requester == this)
      {
        if (command == "dbstatus")
          {
            // Should be installing breakpoints in this file
            /*
              octave:1> result = dbstatus
              result =

              0x1 struct array containing the fields:

              name
              file
              line
            */
            // Check for results that match "file".
          }
      }
  }

  void file_editor_tab::new_file (const QString& commands)
  {
    update_window_title (false); // window title (no modification)

    QSettings *settings = resource_manager::get_settings ();

    // set the eol mode from the settings or depending on the OS if the entry is
    // missing in the settings
#if defined (Q_OS_WIN32)
    int eol_mode = QsciScintilla::EolWindows;
#elif defined (Q_OS_MAC)
    int eol_mode = QsciScintilla::EolMac;
#else
    int eol_mode = QsciScintilla::EolUnix;
#endif
    _edit_area->setEolMode (
      static_cast<QsciScintilla::EolMode> (
        settings->value ("editor/default_eol_mode",eol_mode).toInt ()));

    update_eol_indicator ();

    update_lexer ();

    _edit_area->setText (commands);
    _edit_area->setModified (false); // new file is not modified yet
  }

  // Force reloading of a file after it is saved.
  // This is needed to get the right line numbers for breakpoints (bug #46632).
  bool file_editor_tab::exit_debug_and_clear (const QString& full_name_q,
                                              const QString& base_name_q)
  {
    symbol_table& symtab
      = __get_symbol_table__ ("file_editor_tab::exit_debug_and_clear");

    std::string base_name = base_name_q.toStdString ();
    octave_value sym;
    try
      {
        sym = symtab.find (base_name);
      }
    catch (const execution_exception& e)
      {
        // Ignore syntax error.
        // It was in the old file on disk; the user may have fixed it already.
      }

    // Return early if this file is not loaded in the symbol table
    if (! sym.is_defined () || ! sym.is_user_code ())
      return true;

    octave_user_code *fcn = sym.user_code_value ();

    std::string full_name = full_name_q.toStdString ();
    if (sys::canonicalize_file_name (full_name.c_str ())
        != sys::canonicalize_file_name (fcn->fcn_file_name ().c_str ()))
      return true;

    // If this file is loaded, check that we aren't currently running it
    bool retval = true;
    octave_idx_type curr_frame = -1;
    size_t nskip = 0;
    call_stack& cs
      = __get_call_stack__ ("file_editor_tab::exit_debug_and_clear");
    octave_map stk = cs.backtrace (nskip, curr_frame, false);
    Cell names = stk.contents ("name");
    for (octave_idx_type i = names.numel () - 1; i >= 0; i--)
      {
        if (names(i).string_value () == base_name)
          {
            int ans = QMessageBox::question (nullptr, tr ("Debug or Save"),
                                             tr ("This file is currently being executed.\n"
                                                 "Quit debugging and save?"),
                                             QMessageBox::Save | QMessageBox::Cancel);

            if (ans == QMessageBox::Save)
              {
                emit execute_command_in_terminal_signal ("dbquit");
                // Wait until dbquit has actually occurred
                while (names.numel () > i)
                  {
                    octave_sleep (0.01);
                    stk = cs.backtrace (nskip, curr_frame, false);
                    names = stk.contents ("name");
                  }
              }
            else
              retval = false;
            break;
          }
      }

    // If we aren't currently running it, or have quit above, force a reload.
    if (retval == true)
      symtab.clear_user_function (base_name);

    return retval;
  }

  void file_editor_tab::save_file (const QString& saveFileName,
                                   bool remove_on_success,
                                   bool restore_breakpoints)
  {
    // If it is a new file with no name, signal that saveFileAs
    // should be performed.
    if (! valid_file_name (saveFileName))
      {
        save_file_as (remove_on_success);
        return;
      }

    // Get a list of breakpoint line numbers, before  exit_debug_and_clear().
    emit report_marker_linenr (_bp_lines, _bp_conditions);

    // get the absolute path (if existing)
    QFileInfo file_info = QFileInfo (saveFileName);
    QString file_to_save;
    if (file_info.exists ())
      {
        file_to_save = file_info.canonicalFilePath ();
        // Force reparse of this function next time it is used (bug #46632)
        if ((Fisdebugmode ())(0).is_true ()
            && ! exit_debug_and_clear (file_to_save, file_info.baseName ()))
          return;
      }
    else
      file_to_save = saveFileName;
    QFile file (file_to_save);

    // stop watching file
    QStringList trackedFiles = _file_system_watcher.files ();
    if (trackedFiles.contains (file_to_save))
      _file_system_watcher.removePath (file_to_save);

    // open the file for writing
    if (! file.open (QIODevice::WriteOnly))
      {
        // Unsuccessful, begin watching file again if it was being
        // watched previously.
        if (trackedFiles.contains (file_to_save))
          _file_system_watcher.addPath (file_to_save);

        // Create a NonModal message about error.
        QMessageBox *msgBox
          = new QMessageBox (QMessageBox::Critical,
                             tr ("Octave Editor"),
                             tr ("Could not open file %1 for write:\n%2.").
                             arg (file_to_save).arg (file.errorString ()),
                             QMessageBox::Ok, nullptr);
        show_dialog (msgBox, false);

        return;
      }

    // save the contents into the file

    _encoding = _new_encoding;    // consider a possible new encoding

    // set the desired codec (if suitable for contents)
    QTextCodec *codec = QTextCodec::codecForName (_encoding.toLatin1 ());

    if (check_valid_codec (codec))
      {
        save_file_as (remove_on_success);
        return;
      }

    // write the file
    QTextStream out (&file);
    out.setCodec (codec);

    QApplication::setOverrideCursor (Qt::WaitCursor);
    out << _edit_area->text ();
    out.flush ();
    QApplication::restoreOverrideCursor ();
    file.flush ();
    file.close ();

    // file exists now
    file_info = QFileInfo (file);
    file_to_save = file_info.canonicalFilePath ();

    // save filename after closing file as set_file_name starts watching again
    set_file_name (file_to_save);   // make absolute

    // set the window title to actual filename (not modified)
    update_window_title (false);

    // files is save -> not modified, update encoding in statusbar
    _edit_area->setModified (false);
    _enc_indicator->setText (_encoding);

    if (remove_on_success)
      {
        emit tab_remove_request ();
        return;  // Don't touch member variables after removal
      }

    // Attempt to restore the breakpoints if that is desired.
    // This is only allowed if the tab is not closing since changing
    // breakpoints would reopen the tab in this case.
    if (restore_breakpoints)
      check_restore_breakpoints ();
  }

  void file_editor_tab::save_file_as (bool remove_on_success)
  {
    // Simply put up the file chooser dialog box with a slot connection
    // then return control to the system waiting for a file selection.

    // reset _new_encoding
    _new_encoding = _encoding;

    // If the tab is removed in response to a QFileDialog signal, the tab
    // can't be a parent.
    QFileDialog *fileDialog;
    if (remove_on_success)
      {
        // If tab is closed, "this" cannot be parent in which case modality
        // has no effect.  Disable editing instead.
        _edit_area->setReadOnly (true);
        fileDialog = new QFileDialog ();
      }
    else
      fileDialog = new QFileDialog (this);

    // Giving trouble under KDE (problem is related to Qt signal handling on unix,
    // see https://bugs.kde.org/show_bug.cgi?id=260719 ,
    // it had/has no effect on Windows, though)
    fileDialog->setOption (QFileDialog::DontUseNativeDialog, true);

    // define a new grid layout with the extra elements
    QGridLayout *extra = new QGridLayout (fileDialog);
    QFrame *separator = new QFrame (fileDialog);
    separator->setFrameShape (QFrame::HLine);   // horizontal line as separator
    separator->setFrameStyle (QFrame::Sunken);

    // combo box for choosing new line ending chars
    QLabel *label_eol = new QLabel (tr ("Line Endings:"));
    QComboBox *combo_eol = new QComboBox ();
    combo_eol->addItem ("Windows (CRLF)");  // ensure the same order as in
    combo_eol->addItem ("Mac (CR)");        // the settings dialog
    combo_eol->addItem ("Unix (LF)");
    _save_as_desired_eol = _edit_area->eolMode ();      // init with current eol
    combo_eol->setCurrentIndex (_save_as_desired_eol);

    // combo box for encoding
    QLabel *label_enc = new QLabel (tr ("File Encoding:"));
    QComboBox *combo_enc = new QComboBox ();
    resource_manager::combo_encoding (combo_enc, _encoding);

    // track changes in the combo boxes
    connect (combo_eol, SIGNAL (currentIndexChanged (int)),
             this, SLOT (handle_combo_eol_current_index (int)));
    connect (combo_enc, SIGNAL (currentIndexChanged (QString)),
             this, SLOT (handle_combo_enc_current_index (QString)));

    // build the extra grid layout
    extra->addWidget (separator,0,0,1,6);
    extra->addWidget (label_eol,1,0);
    extra->addWidget (combo_eol,1,1);
    extra->addItem   (new QSpacerItem (1,20,QSizePolicy::Fixed,
                                       QSizePolicy::Fixed), 1,2);
    extra->addWidget (label_enc,1,3);
    extra->addWidget (combo_enc,1,4);
    extra->addItem   (new QSpacerItem (1,20,QSizePolicy::Expanding,
                                       QSizePolicy::Fixed), 1,5);

    // and add the extra grid layout to the dialog's layout
    QGridLayout *dialog_layout = dynamic_cast<QGridLayout *> (fileDialog->layout ());
    dialog_layout->addLayout (extra,dialog_layout->rowCount (),0,
                              1,dialog_layout->columnCount ());

    // add the possible filters and the default suffix
    QStringList filters;
    filters << tr ("Octave Files (*.m)")
            << tr ("All Files (*)");
    fileDialog->setNameFilters (filters);
    fileDialog->setDefaultSuffix ("m");

    if (valid_file_name ())
      {
        fileDialog->selectFile (_file_name);
        QFileInfo file_info (_file_name);
        if (file_info.suffix () != "m")
          {
            // it is not an octave file
            fileDialog->selectNameFilter (filters.at (1));  // "All Files"
            fileDialog->setDefaultSuffix ("");              // no default suffix
          }
      }
    else
      {
        fileDialog->selectFile ("");
        fileDialog->setDirectory (_ced);

        // propose a name corresponding to the function name
        QString fname = get_function_name ();
        if (! fname.isEmpty ())
          fileDialog->selectFile (fname + ".m");
      }

    fileDialog->setAcceptMode (QFileDialog::AcceptSave);
    fileDialog->setViewMode (QFileDialog::Detail);

    connect (fileDialog, SIGNAL (filterSelected (const QString&)),
             this, SLOT (handle_save_as_filter_selected (const QString&)));

    if (remove_on_success)
      {
        connect (fileDialog, SIGNAL (fileSelected (const QString&)),
                 this, SLOT (handle_save_file_as_answer_close (const QString&)));

        connect (fileDialog, SIGNAL (rejected ()),
                 this, SLOT (handle_save_file_as_answer_cancel ()));
      }
    else
      {
        connect (fileDialog, SIGNAL (fileSelected (const QString&)),
                 this, SLOT (handle_save_file_as_answer (const QString&)));
      }

    show_dialog (fileDialog, ! valid_file_name ());
  }

  void file_editor_tab::handle_combo_eol_current_index (int index)
  {
    _save_as_desired_eol = static_cast<QsciScintilla::EolMode> (index);
  }

  void file_editor_tab::handle_combo_enc_current_index (QString text)
  {
    _new_encoding = text;
  }

  void file_editor_tab::handle_save_as_filter_selected (const QString& filter)
  {
    QFileDialog *file_dialog = qobject_cast<QFileDialog *> (sender ());

    QRegExp rx ("\\*\\.([^ ^\\)]*)[ \\)]");   // regexp for suffix in filter
    int index = rx.indexIn (filter,0);        // get first suffix in filter

    if (index > -1)
      file_dialog->setDefaultSuffix (rx.cap (1)); // found a suffix, set default
    else
      file_dialog->setDefaultSuffix ("");         // not found, clear default
  }

  bool file_editor_tab::check_valid_identifier (QString file_name)
  {
    QFileInfo file = QFileInfo (file_name);
    QString base_name = file.baseName ();

    if ((file.suffix () == "m")
        && (! valid_identifier (base_name.toStdString ())))
      {
        int ans = QMessageBox::question (nullptr, tr ("Octave Editor"),
                                         tr ("\"%1\"\n"
                                             "is not a valid identifier.\n\n"
                                             "If you keep this filename, you will not be able to\n"
                                             "call your script using its name as an Octave command.\n\n"
                                             "Do you want to choose another name?").arg (base_name),
                                         QMessageBox::Yes | QMessageBox::No, QMessageBox::Yes);

        if (ans == QMessageBox::Yes)
          return true;
      }

    return false;
  }

  bool file_editor_tab::check_valid_codec (QTextCodec *codec)
  {
    if (! codec)
      {
        QMessageBox::critical (nullptr,
                               tr ("Octave Editor"),
                               tr ("The current encoding %1\n"
                                   "can not be applied.\n\n"
                                   "Please select another one or cancel saving!").arg (_encoding));

        return true;
      }

    if (! codec->canEncode (_edit_area->text ()))
      {
        int ans = QMessageBox::warning (nullptr,
                                        tr ("Octave Editor"),
                                        tr ("The current editor contents can not be encoded\n"
                                            "with the selected encoding %1.\n"
                                            "Using it will result in data loss!\n\n"
                                            "Do you want to choose another encoding?").arg (_encoding),
                                        QMessageBox::Yes | QMessageBox::No, QMessageBox::Yes);

        if (ans == QMessageBox::Yes)
          return true;
      }

    return false;
  }

  void file_editor_tab::handle_save_file_as_answer (const QString& saveFileName)
  {
    if (_save_as_desired_eol != _edit_area->eolMode ())
      convert_eol (this,_save_as_desired_eol);

    if (saveFileName == _file_name)
      {
        save_file (saveFileName);
      }
    else
      {
        // Have editor check for conflict, do not delete tab after save.
        if (check_valid_identifier (saveFileName))
          save_file_as (false);
        else
          emit editor_check_conflict_save (saveFileName, false);
      }
  }

  void file_editor_tab::handle_save_file_as_answer_close (const QString& saveFileName)
  {
    if (_save_as_desired_eol != _edit_area->eolMode ())
      {
        _edit_area->setReadOnly (false);  // was set to read-only in save_file_as
        convert_eol (this,_save_as_desired_eol);
        _edit_area->setReadOnly (true);   // restore read-only mode
      }

    // saveFileName == _file_name can not happen, because we only can get here
    // when we close a tab and _file_name is not a valid filename yet

    // Have editor check for conflict, delete tab after save.
    if (check_valid_identifier (saveFileName))
      save_file_as (true);
    else
      emit editor_check_conflict_save (saveFileName, true);
  }

  void file_editor_tab::handle_save_file_as_answer_cancel (void)
  {
    // User canceled, allow editing again.
    _edit_area->setReadOnly (false);
  }

  void file_editor_tab::file_has_changed (const QString&, bool do_close)
  {
    // Prevent popping up multiple message boxes when the file has
    // been changed multiple times by temporarily removing from the
    // file watcher.
    QStringList trackedFiles = _file_system_watcher.files ();
    if (! trackedFiles.isEmpty ())
      _file_system_watcher.removePath (_file_name);

    if (QFile::exists (_file_name) && ! do_close)
      {
        // The file is modified
        if (_always_reload_changed_files)

          load_file (_file_name);

        else
          {
            // give editor and this tab the focus,
            // possibly making the editor visible if it is hidden
            emit set_focus_editor_signal (this);
            _edit_area->setFocus ();

            // Create a WindowModal message that blocks the edit area
            // by making _edit_area parent.
            QMessageBox *msgBox
              = new QMessageBox (QMessageBox::Warning,
                                 tr ("Octave Editor"),
                                 tr ("It seems that \'%1\' has been modified by another application. Do you want to reload it?").
                                 arg (_file_name),
                                 QMessageBox::Yes | QMessageBox::No, this);

            connect (msgBox, SIGNAL (finished (int)),
                     this, SLOT (handle_file_reload_answer (int)));

            msgBox->setWindowModality (Qt::WindowModal);
            msgBox->setAttribute (Qt::WA_DeleteOnClose);
            msgBox->show ();
          }
      }
    else
      {
        // If desired and if file is not modified,
        // close the file without any user interaction
        if (do_close && ! _edit_area->isModified ())
          {
            handle_file_resave_answer (QMessageBox::Cancel);
            return;
          }

        // give editor and this tab the focus,
        // possibly making the editor visible  if it is hidden
        emit set_focus_editor_signal (this);
        _edit_area->setFocus ();

        QString modified = "";
        if (_edit_area->isModified ())
          modified = tr ("\n\nWarning: The contents in the editor is modified!");

        // Create a WindowModal message. The file editor tab can't be made
        // parent because it may be deleted depending upon the response.
        // Instead, change the _edit_area to read only.
        QMessageBox *msgBox
          = new QMessageBox (QMessageBox::Warning, tr ("Octave Editor"),
                             tr ("It seems that the file\n"
                                 "%1\n"
                                 "has been deleted or renamed. Do you want to save it now?%2").
                             arg (_file_name).arg (modified),
                             QMessageBox::Save | QMessageBox::Close, nullptr);

        _edit_area->setReadOnly (true);

        connect (msgBox, SIGNAL (finished (int)),
                 this, SLOT (handle_file_resave_answer (int)));

        msgBox->setWindowModality (Qt::WindowModal);
        msgBox->setAttribute (Qt::WA_DeleteOnClose);
        msgBox->show ();
      }
  }

  void file_editor_tab::notice_settings (const QSettings *settings, bool init)
  {
    // QSettings pointer is checked before emitting.

    if (! init)
      update_lexer_settings ();

    // code folding
    if (settings->value ("editor/code_folding",true).toBool ())
      {
        _edit_area->setMarginType (3, QsciScintilla::SymbolMargin);
        _edit_area->setFolding (QsciScintilla::BoxedTreeFoldStyle , 3);
      }
    else
      {
        _edit_area->setFolding (QsciScintilla::NoFoldStyle, 3);
      }

    // status bar
    if (settings->value ("editor/show_edit_status_bar",true).toBool ())
      _status_bar->show ();
    else
      _status_bar->hide ();

    //highlight current line color
    QVariant default_var = QColor (240, 240, 240);
    QColor setting_color = settings->value ("editor/highlight_current_line_color",
                                            default_var).value<QColor> ();
    _edit_area->setCaretLineBackgroundColor (setting_color);
    _edit_area->setCaretLineVisible
      (settings->value ("editor/highlightCurrentLine", true).toBool ());

    bool match_keywords = settings->value
                          ("editor/codeCompletion_keywords",true).toBool ();
    bool match_document = settings->value
                          ("editor/codeCompletion_document",true).toBool ();

    QsciScintilla::AutoCompletionSource source = QsciScintilla::AcsNone;
    if (match_keywords)
      if (match_document)
        source = QsciScintilla::AcsAll;
      else
        source = QsciScintilla::AcsAPIs;
    else if (match_document)
      source = QsciScintilla::AcsDocument;
    _edit_area->setAutoCompletionSource (source);

    _edit_area->setAutoCompletionReplaceWord
      (settings->value ("editor/codeCompletion_replace",false).toBool ());
    _edit_area->setAutoCompletionCaseSensitivity
      (settings->value ("editor/codeCompletion_case",true).toBool ());

    if (settings->value ("editor/codeCompletion", true).toBool ())
      _edit_area->setAutoCompletionThreshold
        (settings->value ("editor/codeCompletion_threshold",2).toInt ());
    else
      _edit_area->setAutoCompletionThreshold (-1);

    if (settings->value ("editor/show_white_space",false).toBool ())
      if (settings->value ("editor/show_white_space_indent",false).toBool ())
        _edit_area->setWhitespaceVisibility (QsciScintilla::WsVisibleAfterIndent);
      else
        _edit_area->setWhitespaceVisibility (QsciScintilla::WsVisible);
    else
      _edit_area->setWhitespaceVisibility (QsciScintilla::WsInvisible);

    _edit_area->setEolVisibility (
                                  settings->value ("editor/show_eol_chars",false).toBool ());

    if (settings->value ("editor/showLineNumbers", true).toBool ())
      {
        _edit_area->setMarginLineNumbers (2, true);
        auto_margin_width ();
        connect (_edit_area, SIGNAL (linesChanged ()),
                 this, SLOT (auto_margin_width ()));
      }
    else
      {
        _edit_area->setMarginLineNumbers (2, false);
        disconnect (_edit_area, SIGNAL (linesChanged ()), nullptr, nullptr);
      }

    _smart_indent = settings->value ("editor/auto_indent",true).toBool ();
    _edit_area->setAutoIndent (_smart_indent);
    _edit_area->setTabIndents
      (settings->value ("editor/tab_indents_line",false).toBool ());
    _edit_area->setBackspaceUnindents
      (settings->value ("editor/backspace_unindents_line",false).toBool ());
    _edit_area->setIndentationGuides
      (settings->value ("editor/show_indent_guides",false).toBool ());
    _edit_area->setIndentationsUseTabs
      (settings->value ("editor/indent_uses_tabs",false).toBool ());
    _edit_area->setIndentationWidth
      (settings->value ("editor/indent_width",2).toInt ());

    _edit_area->setTabWidth
      (settings->value ("editor/tab_width",2).toInt ());

    _edit_area->SendScintilla (QsciScintillaBase::SCI_SETHSCROLLBAR,
                               settings->value ("editor/show_hscroll_bar",true).toBool ());
    _edit_area->SendScintilla (QsciScintillaBase::SCI_SETSCROLLWIDTH,-1);
    _edit_area->SendScintilla (QsciScintillaBase::SCI_SETSCROLLWIDTHTRACKING,true);

    _long_title = settings->value ("editor/longWindowTitle", false).toBool ();
    update_window_title (_edit_area->isModified ());

    _auto_endif = settings->value ("editor/auto_endif",1).toInt ();

    // long line marker
    int line_length = settings->value ("editor/long_line_column",80).toInt ();
    _edit_area->setEdgeColumn (line_length);

    if (settings->value ("editor/long_line_marker",true).toBool ())
      {
        if (settings->value ("editor/long_line_marker_line",true).toBool ())
          _edit_area->setEdgeMode (QsciScintilla::EdgeLine);
        else
          {
            if (settings->value ("editor/long_line_marker_background",false)
                .toBool ())
              _edit_area->setEdgeMode (QsciScintilla::EdgeBackground);
            else
              _edit_area->setEdgeMode (QsciScintilla::EdgeLine);
          }
      }
    else
      _edit_area->setEdgeMode (QsciScintilla::EdgeNone);

    // line wrapping and breaking
    _edit_area->setWrapVisualFlags (QsciScintilla::WrapFlagByBorder);
    _edit_area->setWrapIndentMode (QsciScintilla::WrapIndentSame);

    if (settings->value ("editor/wrap_lines",false).toBool ())
      _edit_area->setWrapMode (QsciScintilla::WrapWord);
    else
      _edit_area->setWrapMode (QsciScintilla::WrapNone);

    if (settings->value ("editor/break_lines",false).toBool ())
      _line_break = line_length;
    else
      _line_break = 0;

    _line_break_comments =
      settings->value ("editor/break_lines_comments",false).toBool ();

    // highlight all occurrences of a word selected by a double click
    _highlight_all_occurrences =
      settings->value ("editor/highlight_all_occurrences", true).toBool ();

    // reload changed files
    _always_reload_changed_files =
      settings->value ("editor/always_reload_changed_files",false).toBool ();

    // Set cursor blinking depending on the settings.
    // QScintilla ignores the application global settings, so some special
    // handling is required
    bool cursor_blinking;

    if (settings->contains ("cursor_blinking"))
      cursor_blinking = settings->value ("cursor_blinking",true).toBool ();
    else
      cursor_blinking = settings->value ("terminal/cursorBlinking",true).toBool ();

    if (cursor_blinking)
      _edit_area->SendScintilla (QsciScintillaBase::SCI_SETCARETPERIOD,500);
    else
      _edit_area->SendScintilla (QsciScintillaBase::SCI_SETCARETPERIOD,0);

  }


  void file_editor_tab::auto_margin_width (void)
  {
    _edit_area->setMarginWidth (2, "1" + QString::number (_edit_area->lines ()));
  }

  // the following close request was changed from a signal slot into a
  // normal function because we need the return value from close whether
  // the tab really was closed (for canceling exiting octave).
  // When emitting a signal, only the return value from the last slot
  // goes back to the sender
  bool file_editor_tab::conditional_close (void)
  {
    return close ();
  }

  void file_editor_tab::change_editor_state (const QWidget *ID)
  {
    if (ID != this)
      {
        // Widget may be going out of focus.  If so, record location.
        if (_find_dialog)
          {
            if (_find_dialog->isVisible ())
              {
                _find_dialog_geometry = _find_dialog->geometry ();
                _find_dialog->hide ();
              }
          }
        return;
      }

    if (_find_dialog && _find_dialog_is_visible)
      {
        _find_dialog->setGeometry (_find_dialog_geometry);
        QPoint p = _find_dialog->pos ();
        _find_dialog->move (p.x ()+10, p.y ()+10);
        _find_dialog->show ();
      }

    emit editor_state_changed (_copy_available, _is_octave_file);
  }

  void file_editor_tab::file_name_query (const QWidget *ID)
  {
    // A zero (null pointer) means that all file editor tabs
    // should respond, otherwise just the desired file editor tab.
    if (ID != this && ID != nullptr)
      return;

    // This list also includes windows with name ""
    emit add_filename_to_list (_file_name, _encoding, this);
  }

  void file_editor_tab::handle_file_reload_answer (int decision)
  {
    if (decision == QMessageBox::Yes)
      {
        // reload: file is readded to the file watcher in set_file_name ()
        load_file (_file_name);
      }
    else
      {
        // do not reload: readd to the file watche
        _file_system_watcher.addPath (_file_name);
      }
  }

  void file_editor_tab::handle_file_resave_answer (int decision)
  {
    // check decision of user in dialog
    if (decision == QMessageBox::Save)
      {
        save_file (_file_name);  // readds file to watcher in set_file_name ()
        _edit_area->setReadOnly (false);  // delete read only flag
      }
    else
      {
        // Definitely close the file.
        // Set modified to false to prevent the dialog box when the close event
        // is posted. If the user cancels the close in this dialog the tab is
        // left open with a non-existing file.
        _edit_area->setModified (false);
        close ();
      }
  }

  void file_editor_tab::insert_debugger_pointer (const QWidget *ID, int line)
  {
    if (ID != this || ID == nullptr)
      return;

    emit remove_all_positions ();  // debugger_position, unsure_debugger_position

    if (line > 0)
      {
        marker *dp;

        if (_edit_area->isModified ())
          {
            // The best that can be done if the editor contents has been
            // modified is to see if there is a match with the original
            // line number of any existing breakpoints.  We can put a normal
            // debugger pointer at that breakpoint position.  Otherwise, it
            // isn't certain whether the original line number and current line
            // number match.
            int editor_linenr = -1;
            marker *dummy;
            emit find_translated_line_number (line, editor_linenr, dummy);
            if (editor_linenr != -1)
              {
                // Match with an existing breakpoint.
                dp = new marker (_edit_area, line,
                                 marker::debugger_position, editor_linenr);
              }
            else
              {
                int original_linenr = -1;
                editor_linenr = -1;
                emit find_linenr_just_before (line, original_linenr, editor_linenr);
                if (original_linenr >= 0)
                  {
                    // Make a guess by using an offset from the breakpoint.
                    int linenr_guess = editor_linenr + line - original_linenr;
                    dp = new marker (_edit_area, line,
                                     marker::unsure_debugger_position,
                                     linenr_guess);
                  }
                else
                  {
                    // Can't make a very good guess, so just use the debugger
                    // line number.
                    dp = new marker (_edit_area, line,
                                     marker::unsure_debugger_position);
                  }
              }
          }
        else
          dp = new marker (_edit_area, line, marker::debugger_position);

        connect (this, SIGNAL (remove_position_via_debugger_linenr (int)),
                 dp,   SLOT (handle_remove_via_original_linenr (int)));
        connect (this, SIGNAL (remove_all_positions (void)),
                 dp,   SLOT (handle_remove (void)));

        center_current_line (false);
      }
  }

  void file_editor_tab::delete_debugger_pointer (const QWidget *ID, int line)
  {
    if (ID != this || ID == nullptr)
      return;

    if (line > 0)
      emit remove_position_via_debugger_linenr (line);
  }

  void file_editor_tab::do_breakpoint_marker (bool insert,
                                              const QWidget *ID, int line,
                                              const QString& cond)
  {
    if (ID != this || ID == nullptr)
      return;

    if (line > 0)
      {
        if (insert)
          {
            int editor_linenr = -1;
            marker *bp = nullptr;

            // If comes back indicating a non-zero breakpoint marker,
            // reuse it if possible
            emit find_translated_line_number (line, editor_linenr, bp);
            if (bp != nullptr)
              {
                if ((cond == "") != (bp->get_cond () == ""))
                  {
                    // can only reuse conditional bp as conditional
                    emit remove_breakpoint_via_debugger_linenr (line);
                    bp = nullptr;
                  }
                else
                  bp->set_cond (cond);
              }

            if (bp == nullptr)
              {
                bp = new marker (_edit_area, line,
                                 cond == "" ? marker::breakpoint
                                 : marker::cond_break, cond);

                connect (this, SIGNAL (remove_breakpoint_via_debugger_linenr
                                       (int)),
                         bp,   SLOT (handle_remove_via_original_linenr (int)));
                connect (this, SIGNAL (request_remove_breakpoint_via_editor_linenr
                                       (int)),
                         bp,   SLOT (handle_request_remove_via_editor_linenr
                                     (int)));
                connect (this, SIGNAL (remove_all_breakpoints (void)),
                         bp,   SLOT (handle_remove (void)));
                connect (this, SIGNAL (find_translated_line_number (int, int&,
                                                                    marker*&)),
                         bp,   SLOT (handle_find_translation (int, int&,
                                                              marker*&)));
                connect (this, SIGNAL (find_linenr_just_before (int, int&, int&)),
                         bp,   SLOT (handle_find_just_before (int, int&, int&)));
                connect (this, SIGNAL (report_marker_linenr (QIntList&,
                                                             QStringList&)),
                         bp,   SLOT (handle_report_editor_linenr (QIntList&,
                                                                  QStringList&)));
                connect (bp,   SIGNAL (request_remove (int)),
                         this, SLOT (handle_request_remove_breakpoint (int)));
              }
          }
        else
          emit remove_breakpoint_via_debugger_linenr (line);
      }
  }

  void file_editor_tab::center_current_line (bool always)
  {
    long int visible_lines
      = _edit_area->SendScintilla (QsciScintillaBase::SCI_LINESONSCREEN);

    if (visible_lines > 2)
      {
        int line, index;
        _edit_area->getCursorPosition (&line, &index);
        // compensate for "folding":
        // step 1: expand the current line, if it was folded
        _edit_area->SendScintilla (2232, line);   // SCI_ENSUREVISIBLE

        // step 2: map file line num to "visible" one // SCI_VISIBLEFROMDOCLINE
        int vis_line = _edit_area->SendScintilla (2220, line);

        int first_line = _edit_area->firstVisibleLine ();

        if (always || vis_line == first_line
            || vis_line > first_line + visible_lines - 2)
          {
            first_line += (vis_line - first_line - (visible_lines - 1) / 2);
            _edit_area->SendScintilla (2613, first_line); // SCI_SETFIRSTVISIBLELINE
          }
      }
  }

  void file_editor_tab::handle_lines_changed (void)
  {
    // the related signal is emitted before cursor-move-signal!
    _lines_changed = true;
  }

  void file_editor_tab::handle_cursor_moved (int line, int col)
  {
    if (_edit_area->SendScintilla (QsciScintillaBase::SCI_AUTOCACTIVE))
      show_auto_completion (this);

    if (_lines_changed)  // cursor moved and lines have changed
      {
        _lines_changed = false;
        if (_is_octave_file && line == _line+1 && col < _col)
          {
            // Obviously, we have a newline here
            if (_smart_indent || _auto_endif)
              _edit_area->smart_indent (_smart_indent, _auto_endif, _line);
          }
      }

    _line = line;
    _col  = col;

    _row_indicator->setNum (line+1);
    _col_indicator->setNum (col+1);
  }

  // Slot that is entered each time a new character was typed.
  // It is used for handling line breaking if this is desired.
  // The related signal is emitted after the signal for a moved cursor
  // such that _col and _line can not be used for current position.
  void file_editor_tab::handle_char_added (int)
  {
    if (_line_break)
      {
        // If line breaking is desired, get the current line and column.
        // For taking the tab width into consideration, use own function
        int line, col, pos;
        _edit_area->get_current_position (&pos, &line, &col);

        // immediately return if line has not reached the max. line length
        if (col <= _line_break)
          return;

        // If line breaking is only desired in comments,
        // return if not in a comment
        int style_comment = octave_qscintilla::ST_NONE;
        if (_line_break_comments)
          {
            // line breaking only in comments, check for comment style
            style_comment = _edit_area->is_style_comment ();
            if (! style_comment)
              return;       // no comment, return
          }

        // Here we go for breaking the current line by inserting a newline.
        // For determining the position of a specific column, we have to get
        // the column from the QScintila function without taking tab lengths
        // into account, since the calculation from line/col to position ignores
        // this, too
        _edit_area->getCursorPosition (&line, &col);
        int c = 0;
        int col_space = col;
        int indentation = _edit_area->indentation (line);

        // Search the first occurence of space or tab backwards starting from
        // the current column (col_space).
        while (c != ' ' && c != '\t' && col_space > indentation)
          {
            pos = _edit_area->positionFromLineIndex (line, col_space--);
            c = _edit_area->SendScintilla (QsciScintillaBase::SCI_GETCHARAT, pos);
          }

        // If a space or tab was found, break at this char,
        // otherwise break at cursor position
        int col_newline = col - 1;
        if (c == ' ' || c == '\t')
          col_newline = col_space + 1;

        // Insert a newline char for breaking the line possibly followed
        // by a line comment string
        QString newline = QString ("\n");
        style_comment = _edit_area->is_style_comment ();
        if (style_comment == octave_qscintilla::ST_LINE_COMMENT)
          newline = newline + _edit_area->comment_string ().at (0);
        _edit_area->insertAt (newline, line, col_newline);

        // Automatically indent the new line to the indentation of previous line
        // and set the cursor position to the end of the indentation.
        _edit_area->setIndentation (line + 1, indentation);
        _edit_area->SendScintilla (QsciScintillaBase::SCI_LINEEND);
      }
  }

  // Slot handling a double click into the text area
  void file_editor_tab::handle_double_click (int, int, int modifier)
  {
    if (! modifier)
      {
        // double clicks without modifier
        // clear any existing indicators of this type
        _edit_area->clear_selection_markers ();

        if (_highlight_all_occurrences)
          {
            // Clear any previous selection.
            _edit_area->set_word_selection ();

            // highlighting of all occurrences of the clicked word is enabled

            // get the resulting cursor position
            // (required if click was beyond a line ending)
            int line, col;
            _edit_area->getCursorPosition (&line, &col);

            // get the word at the cursor (if any)
            QString word = _edit_area->wordAtLineIndex (line, col);
            word = word.trimmed ();

            if (! word.isEmpty ())
              {
                // word is not empty, so find all occurrences of the word

                // remember first visible line for restoring the view afterwards
                int first_line = _edit_area->firstVisibleLine ();

                // search for first occurrence of the detected word
                bool find_result_available
                  = _edit_area->findFirst (word,
                                           false,   // no regexp
                                           true,    // case sensitive
                                           true,    // whole words only
                                           false,   // do not wrap
                                           true,    // forward
                                           0,0,     // from the beginning
                                           false
#if defined (HAVE_QSCI_VERSION_2_6_0)
                                           , true
#endif
                                          );

                // loop over all occurrences and set the related indicator
                int oline, ocol;
                int wlen = word.length ();

                while (find_result_available)
                  {
                    // get cursor position after having found an occurrence
                    _edit_area->getCursorPosition (&oline, &ocol);
                    // mark the selection
                    _edit_area->show_selection_markers (oline, ocol, wlen);

                    // find next occurrence
                    find_result_available = _edit_area->findNext ();
                  }

                // restore the visible area of the file, the cursor position,
                // and the selection
                _edit_area->setFirstVisibleLine (first_line);
                _edit_area->setCursorPosition (line, col);
                _edit_area->setSelection (line, col - wlen, line, col);
                _edit_area->set_word_selection (word);
              }
          }
      }
  }

  QString file_editor_tab::get_function_name (void)
  {
    QRegExp rxfun1 ("^[\t ]*function[^=]+=([^\\(]+)\\([^\\)]*\\)[\t ]*$");
    QRegExp rxfun2 ("^[\t ]*function[\t ]+([^\\(]+)\\([^\\)]*\\)[\t ]*$");
    QRegExp rxfun3 ("^[\t ]*function[^=]+=[\t ]*([^\\s]+)[\t ]*$");
    QRegExp rxfun4 ("^[\t ]*function[\t ]+([^\\s]+)[\t ]*$");

    QStringList lines = _edit_area->text ().split ("\n");

    for (int i = 0; i < lines.count (); i++)
      {
        if (rxfun1.indexIn (lines.at (i)) != -1)
          return rxfun1.cap (1).remove (QRegExp ("[ \t]*"));
        else if (rxfun2.indexIn (lines.at (i)) != -1)
          return rxfun2.cap (1).remove (QRegExp ("[ \t]*"));
        else if (rxfun3.indexIn (lines.at (i)) != -1)
          return rxfun3.cap (1).remove (QRegExp ("[ \t]*"));
        else if (rxfun4.indexIn (lines.at (i)) != -1)
          return rxfun4.cap (1).remove (QRegExp ("[ \t]*"));
      }

    return QString ();
  }
}

#endif