mosh/src/terminal/terminalframebuffer.cc

/*
    Mosh: the mobile shell
    Copyright 2012 Keith Winstein

    This program 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.

    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <boost/typeof/typeof.hpp>
#include <assert.h>
#include <stdio.h>

#include "terminalframebuffer.h"

using namespace Terminal;

void Cell::reset( int background_color )
{
  contents.clear();
  fallback = false;
  width = 1;
  renditions = Renditions( background_color );
}

DrawState::DrawState( int s_width, int s_height )
  : width( s_width ), height( s_height ),
    cursor_col( 0 ), cursor_row( 0 ),
    combining_char_col( 0 ), combining_char_row( 0 ), tabs( s_width ),
    scrolling_region_top_row( 0 ), scrolling_region_bottom_row( height - 1 ),
    renditions( 0 ), save(),
    next_print_will_wrap( false ), origin_mode( false ), auto_wrap_mode( true ),
    insert_mode( false ), cursor_visible( true ), reverse_video( false ),
    application_mode_cursor_keys( false )
{
  for ( int i = 0; i < width; i++ ) {
    tabs[ i ] = ( (i % 8) == 0 );
  }
}

Framebuffer::Framebuffer( int s_width, int s_height )
  : rows( s_height, Row( s_width, 0 ) ), window_title(), bell_count( 0 ), ds( s_width, s_height )
{
  assert( s_height > 0 );
  assert( s_width > 0 );
}

void Framebuffer::scroll( int N )
{
  if ( N >= 0 ) {
    for ( int i = 0; i < N; i++ ) {
      delete_line( ds.get_scrolling_region_top_row() );
      ds.move_row( -1, true );
    }
  } else {
    N = -N;

    for ( int i = 0; i < N; i++ ) {
      rows.insert( rows.begin() + ds.get_scrolling_region_top_row(), newrow() );
      rows.erase( rows.begin() + ds.get_scrolling_region_bottom_row() + 1 );
      ds.move_row( 1, true );
    }
  }
}

void DrawState::new_grapheme( void )
{
  combining_char_col = cursor_col;
  combining_char_row = cursor_row;  
}

void DrawState::snap_cursor_to_border( void )
{
  if ( cursor_row < limit_top() ) cursor_row = limit_top();
  if ( cursor_row > limit_bottom() ) cursor_row = limit_bottom();
  if ( cursor_col < 0 ) cursor_col = 0;
  if ( cursor_col >= width ) cursor_col = width - 1;
}

void DrawState::move_row( int N, bool relative )
{
  if ( relative ) {
    cursor_row += N;
  } else {
    cursor_row = N + limit_top();
  }

  snap_cursor_to_border();
  new_grapheme();
  next_print_will_wrap = false;
}

void DrawState::move_col( int N, bool relative, bool implicit )
{
  if ( implicit ) {
    new_grapheme();
  }

  if ( relative ) {
    cursor_col += N;
  } else {
    cursor_col = N;
  }

  if ( implicit && (cursor_col >= width) ) {
    next_print_will_wrap = true;
  }

  snap_cursor_to_border();
  if ( !implicit ) {
    new_grapheme();
    next_print_will_wrap = false;
  }
}

void Framebuffer::move_rows_autoscroll( int rows )
{
  /* don't scroll if outside the scrolling region */
  if ( (ds.get_cursor_row() < ds.get_scrolling_region_top_row())
       || (ds.get_cursor_row() > ds.get_scrolling_region_bottom_row()) ) {
    ds.move_row( rows, true );
    return;
  }

  if ( ds.get_cursor_row() + rows > ds.get_scrolling_region_bottom_row() ) {
    scroll( ds.get_cursor_row() + rows - ds.get_scrolling_region_bottom_row() );
  } else if ( ds.get_cursor_row() + rows < ds.get_scrolling_region_top_row() ) {
    scroll( ds.get_cursor_row() + rows - ds.get_scrolling_region_top_row() );
  }

  ds.move_row( rows, true );
}

Cell *Framebuffer::get_combining_cell( void )
{
  if ( (ds.get_combining_char_col() < 0)
       || (ds.get_combining_char_row() < 0)
       || (ds.get_combining_char_col() >= ds.get_width())
       || (ds.get_combining_char_row() >= ds.get_height()) ) {
    return NULL;
  } /* can happen if a resize came in between */

  return &rows[ ds.get_combining_char_row() ].cells[ ds.get_combining_char_col() ];
}

void DrawState::set_tab( void )
{
  tabs[ cursor_col ] = true;
}

void DrawState::clear_tab( int col )
{
  tabs[ col ] = false;
}

int DrawState::get_next_tab( void )
{
  for ( int i = cursor_col + 1; i < width; i++ ) {
    if ( tabs[ i ] ) {
      return i;
    }
  }
  return -1;
}

void DrawState::set_scrolling_region( int top, int bottom )
{
  if ( height < 1 ) {
    return;
  }

  scrolling_region_top_row = top;
  scrolling_region_bottom_row = bottom;

  if ( scrolling_region_top_row < 0 ) scrolling_region_top_row = 0;
  if ( scrolling_region_bottom_row >= height ) scrolling_region_bottom_row = height - 1;

  if ( scrolling_region_bottom_row < scrolling_region_top_row )
    scrolling_region_bottom_row = scrolling_region_top_row;
  /* real rule requires TWO-line scrolling region */

  if ( origin_mode ) {
    snap_cursor_to_border();
    new_grapheme();
  }
}

int DrawState::limit_top( void )
{
  return origin_mode ? scrolling_region_top_row : 0;
}

int DrawState::limit_bottom( void )
{
  return origin_mode ? scrolling_region_bottom_row : height - 1;
}

std::vector<int> DrawState::get_tabs( void )
{
  std::vector<int> ret;

  for ( int i = 0; i < width; i++ ) {
    if ( tabs[ i ] ) {
      ret.push_back( i );
    }
  }

  return ret;
}

void Framebuffer::apply_renditions_to_current_cell( void )
{
  get_mutable_cell()->renditions = ds.get_renditions();
}

SavedCursor::SavedCursor()
  : cursor_col( 0 ), cursor_row( 0 ),
    renditions( 0 ),
    auto_wrap_mode( true ),
    origin_mode( false )
{}

void DrawState::save_cursor( void )
{
  save.cursor_col = cursor_col;
  save.cursor_row = cursor_row;
  save.renditions = renditions;
  save.auto_wrap_mode = auto_wrap_mode;
  save.origin_mode = origin_mode;
}

void DrawState::restore_cursor( void )
{
  cursor_col = save.cursor_col;
  cursor_row = save.cursor_row;
  renditions = save.renditions;
  auto_wrap_mode = save.auto_wrap_mode;
  origin_mode = save.origin_mode;

  snap_cursor_to_border(); /* we could have resized in between */
  new_grapheme();
}

void Framebuffer::insert_line( int before_row )
{
  if ( (before_row < ds.get_scrolling_region_top_row())
       || (before_row > ds.get_scrolling_region_bottom_row() + 1) ) {
    return;
  }

  rows.insert( rows.begin() + before_row, newrow() );
  rows.erase( rows.begin() + ds.get_scrolling_region_bottom_row() + 1 );
}

void Framebuffer::delete_line( int row )
{
  if ( (row < ds.get_scrolling_region_top_row())
       || (row > ds.get_scrolling_region_bottom_row()) ) {
    return;
  }

  int insertbefore = ds.get_scrolling_region_bottom_row() + 1;
  if ( insertbefore == ds.get_height() ) {
    rows.push_back( newrow() );
  } else {
    rows.insert( rows.begin() + insertbefore, newrow() );
  }

  rows.erase( rows.begin() + row );
}

void Row::insert_cell( int col, int background_color )
{
  cells.insert( cells.begin() + col, Cell( background_color ) );
  cells.pop_back();
}

void Row::delete_cell( int col, int background_color )
{
  cells.push_back( Cell( background_color ) );
  cells.erase( cells.begin() + col );
}

void Framebuffer::insert_cell( int row, int col )
{
  rows[ row ].insert_cell( col, ds.get_background_rendition() );
}

void Framebuffer::delete_cell( int row, int col )
{
  rows[ row ].delete_cell( col, ds.get_background_rendition() );
}

void Framebuffer::reset( void )
{
  int width = ds.get_width(), height = ds.get_height();
  ds = DrawState( width, height );
  rows = std::deque<Row>( height, newrow() );
  window_title.clear();
  /* do not reset bell_count */
}

void Framebuffer::soft_reset( void )
{
  ds.insert_mode = false;
  ds.origin_mode = false;
  ds.cursor_visible = true; /* per xterm and gnome-terminal */
  ds.application_mode_cursor_keys = false;
  ds.set_scrolling_region( 0, ds.get_height() - 1 );
  ds.add_rendition( 0 );
  ds.clear_saved_cursor();
}

void Framebuffer::posterize( void )
{
  for ( BOOST_AUTO( i, rows.begin() ); i != rows.end(); i++ ) {
    for ( BOOST_AUTO( j, i->cells.begin() ); j != i->cells.end(); j++ ) {
      j->renditions.posterize();
    }
  }
}

void Framebuffer::resize( int s_width, int s_height )
{
  assert( s_width > 0 );
  assert( s_height > 0 );

  rows.resize( s_height, newrow() );

  for ( std::deque<Row>::iterator i = rows.begin();
	i != rows.end();
	i++ ) {
    (*i).cells.resize( s_width, Cell( ds.get_background_rendition() ) );
  }

  ds.resize( s_width, s_height );
}

void DrawState::resize( int s_width, int s_height )
{
  if ( (width != s_width)
       || (height != s_height) ) {
    /* reset entire scrolling region on any resize */
    /* xterm and rxvt-unicode do this. gnome-terminal only
       resets scrolling region if it has to become smaller in resize */
    scrolling_region_top_row = 0;
    scrolling_region_bottom_row = s_height - 1;
  }

  width = s_width;
  height = s_height;

  snap_cursor_to_border();

  tabs.resize( width );

  /* saved cursor will be snapped to border on restore */

  /* invalidate combining char cell if necessary */
  if ( (combining_char_col >= width)
       || (combining_char_row >= height) ) {
    combining_char_col = combining_char_row = -1;
  }
}

Renditions::Renditions( int s_background )
  : bold( false ), underlined( false ), blink( false ),
    inverse( false ), invisible( false ), foreground_color( 0 ),
    background_color( s_background )
{}

/* This routine cannot be used to set a color beyond the 8-color set. */
void Renditions::set_rendition( int num )
{
  if ( num == 0 ) {
    bold = underlined = blink = inverse = invisible = false;
    foreground_color = background_color = 0;
    return;
  }

  if ( num == 39 ) {
    foreground_color = 0;
    return;
  } else if ( num == 49 ) {
    background_color = 0;
    return;
  }

  if ( (30 <= num) && (num <= 37) ) { /* foreground color in 8-color set */
    foreground_color = num;
    return;
  } else if ( (40 <= num) && (num <= 47) ) { /* background color in 8-color set */
    background_color = num;
    return;
  }

  switch ( num ) {
  case 1: case 22: bold = (num == 1); break;
  case 4: case 24: underlined = (num == 4); break;
  case 5: case 25: blink = (num == 5); break;
  case 7: case 27: inverse = (num == 7); break;
  case 8: case 28: invisible = (num == 8); break;
  }
}

void Renditions::set_foreground_color( int num )
{
  if ( (0 <= num) && (num <= 255) ) {
    foreground_color = 30 + num;
  }
}

void Renditions::set_background_color( int num )
{
  if ( (0 <= num) && (num <= 255) ) {
    background_color = 40 + num;
  }
}

std::string Renditions::sgr( void ) const
{
  std::string ret;

  ret.append( "\033[0" );
  if ( bold ) ret.append( ";1" );
  if ( underlined ) ret.append( ";4" );
  if ( blink ) ret.append( ";5" );
  if ( inverse ) ret.append( ";7" );
  if ( invisible ) ret.append( ";8" );

  if ( foreground_color > 37 ) { /* use 256-color set */
    char col[ 64 ];
    snprintf( col, 64, "m\033[38;5;%d", foreground_color - 30 );
    ret.append( col );
  } else if ( foreground_color ) {
    char col[ 8 ];
    snprintf( col, 8, ";%d", foreground_color );
    ret.append( col );
  }

  if ( background_color > 47 ) { /* use 256-color set */
    char col[ 64 ];
    snprintf( col, 64, "m\033[48;5;%d", background_color - 40 );
    ret.append( col );
  } else if ( background_color ) {
    char col[ 8 ];
    snprintf( col, 8, ";%d", background_color );
    ret.append( col );
  }

  ret.append( "m" );

  return ret;
}

/* Reduce 256 "standard" colors to the 8 ANSI colors. */

/* We could do something fancy like find the nearest system color in
   the deltaE(2000) sense, but for "business graphics," the colorimetric
   intent is probably less important than just having separate colors
   be separate as much as possible. */

/* Terminal emulators generally agree on the (R',G',B') values of the
   "standard" 256-color pallette beyond #15, but for the first 16
   colors there is disagreement. Most terminal emulators are roughly
   self-consistent, except on Ubuntu's gnome-terminal where "ANSI
   blue" (#4) has been replaced with the aubergine system-wide
   color. See
   https://lists.ubuntu.com/archives/ubuntu-devel/2011-March/032726.html

   For purposes of this routine, we just treat the eight colors as
   taking each possible assignment of 0 or 255 to their components.

   Terminal emulators that advertise "xterm" are inconsistent on the
   handling of initc to change the contents of a cell in the color
   pallette. On RIS (reset to initial state) or choosing reset from
   the user interface, xterm resets all entries, but gnome-terminal
   only resets entries beyond 16. (rxvt doesn't reset any entries,
   and Terminal.app ignores initc.) On initc, xterm applies changes
   immediately (but slowly), but gnome-terminal's changes are only
   prospective unless the user resizes the terminal.

   mosh ignores initc for now, despite advertising xterm-256color. */

static const char standard_posterization[] = {
  0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7,
  0, 0, 4, 4, 4, 4, 0, 0, 4, 4, 4, 4, 2, 2, 6, 6,
  6, 6, 2, 2, 6, 6, 6, 6, 2, 2, 6, 6, 6, 6, 2, 2,
  6, 6, 6, 6, 0, 0, 4, 4, 4, 4, 0, 0, 4, 4, 4, 4,
  2, 2, 6, 6, 6, 6, 2, 2, 6, 6, 6, 6, 2, 2, 6, 6,
  6, 6, 2, 2, 6, 6, 6, 6, 1, 1, 5, 5, 5, 5, 1, 1,
  5, 5, 5, 5, 3, 3, 7, 7, 7, 7, 3, 3, 7, 7, 7, 7,
  3, 3, 7, 7, 7, 7, 3, 3, 7, 7, 7, 7, 1, 1, 5, 5,
  5, 5, 1, 1, 5, 5, 5, 5, 3, 3, 7, 7, 7, 7, 3, 3,
  7, 7, 7, 7, 3, 3, 7, 7, 7, 7, 3, 3, 7, 7, 7, 7,
  1, 1, 5, 5, 5, 5, 1, 1, 5, 5, 5, 5, 3, 3, 7, 7,
  7, 7, 3, 3, 7, 7, 7, 7, 3, 3, 7, 7, 7, 7, 3, 3,
  7, 7, 7, 7, 1, 1, 5, 5, 5, 5, 1, 1, 5, 5, 5, 5,
  3, 3, 7, 7, 7, 7, 3, 3, 7, 7, 7, 7, 3, 3, 7, 7,
  7, 7, 3, 3, 7, 7, 7, 7, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 };

void Renditions::posterize( void )
{
  if ( foreground_color ) {
    foreground_color = 30 + standard_posterization[ foreground_color - 30 ];
  }

  if ( background_color ) {
    background_color = 40 + standard_posterization[ background_color - 40 ];
  }
}

void Row::reset( int background_color )
{
  for ( std::vector<Cell>::iterator i = cells.begin();
	i != cells.end();
	i++ ) {
    i->reset( background_color );
  }
}

void Framebuffer::prefix_window_title( const std::deque<wchar_t> &s )
{
  for ( BOOST_AUTO( i, s.rbegin() ); i != s.rend(); i++ ) {
    window_title.push_front( *i );
  }
}

wchar_t Cell::debug_contents( void ) const
{
  if ( contents.empty() ) {
    return '_';
  } else {
    return contents.front();
  }
}