From 023eb182d0c5b3de2fdbc08a0cbcb09f27dc95a0 Mon Sep 17 00:00:00 2001
From: Keith Winstein <keithw@mit.edu>
Date: Sat, 13 Aug 2011 15:06:37 -0400
Subject: [PATCH] Refactor display to be outside of terminal and add some const
 correctness

---
 parseraction.cpp        |  4 +-
 termemu.cpp             | 12 ++++--
 terminal.cpp            | 12 +++---
 terminal.hpp            |  3 +-
 terminaldisplay.cpp     | 96 ++++++++++++++++++++++-------------------
 terminaldisplay.hpp     | 22 ++++------
 terminalframebuffer.cpp |  4 +-
 terminalframebuffer.hpp | 60 ++++++++++++++------------
 terminalfunctions.cpp   | 16 +++----
 9 files changed, 123 insertions(+), 106 deletions(-)

diff --git a/parseraction.cpp b/parseraction.cpp
index f5fdf12..3a66845 100644
--- a/parseraction.cpp
+++ b/parseraction.cpp
@@ -70,9 +70,11 @@ void UserByte::act_on_terminal( Terminal::Emulator *emu )
 {
   emu->dispatch.terminal_to_host.append( emu->user.input( this,
 							  emu->fb.ds.application_mode_cursor_keys ) );
-  if ( c == 0x0c ) { /* Ctrl-L */
+  /*
+  if ( c == 0x0c ) { // Ctrl-L
     emu->display.invalidate();
   }
+  */
 }
 
 void Resize::act_on_terminal( Terminal::Emulator *emu )
diff --git a/termemu.cpp b/termemu.cpp
index 34ae148..bdddc6d 100644
--- a/termemu.cpp
+++ b/termemu.cpp
@@ -122,7 +122,7 @@ int main( void )
 }
 
 /* Print a frame if the last frame was more than 1/50 seconds ago */
-bool tick( Terminal::Emulator *e )
+bool tick( Terminal::Emulator *e, Terminal::Display *d, Terminal::Framebuffer &state )
 {
   static bool initialized = false;
   static struct timeval last_time;
@@ -138,8 +138,10 @@ bool tick( Terminal::Emulator *e )
 
   if ( (!initialized)
        || (diff >= 0.02) ) {
-    std::string update = e->new_frame();
+    std::string update = d->new_frame( initialized, state, e->get_fb() );
     swrite( STDOUT_FILENO, update.c_str() );
+    state = e->get_fb();
+
     initialized = true;
     last_time = this_time;
 
@@ -198,6 +200,8 @@ void emulate_terminal( int fd )
   /* open parser and terminal */
   Parser::UTF8Parser parser;
   Terminal::Emulator terminal( window_size.ws_col, window_size.ws_row );
+  Terminal::Display display;
+  Terminal::Framebuffer state( window_size.ws_col, window_size.ws_row );
 
   struct pollfd pollfds[ 3 ];
 
@@ -255,15 +259,17 @@ void emulate_terminal( int fd )
       break;
     }
 
-    if ( tick( &terminal ) ) { /* there was a frame */
+    if ( tick( &terminal, &display, state ) ) { /* there was a frame */
       poll_timeout = -1;
     } else {
       poll_timeout = 20;
     }
   }
 
+  /* XXX last frame
   std::string update = terminal.new_frame();
   swrite( STDOUT_FILENO, update.c_str() );
+  */
 
   swrite( STDOUT_FILENO, terminal.close().c_str() );
 }
diff --git a/terminal.cpp b/terminal.cpp
index fbba772..9414e8d 100644
--- a/terminal.cpp
+++ b/terminal.cpp
@@ -10,7 +10,7 @@
 using namespace Terminal;
 
 Emulator::Emulator( size_t s_width, size_t s_height )
-  : fb( s_width, s_height ), dispatch(), user(), display( s_width, s_height )
+  : fb( s_width, s_height ), dispatch(), user()
 {}
 
 std::string Emulator::read_octets_to_host( void )
@@ -32,7 +32,7 @@ void Emulator::print( Parser::Print *act )
 
   int chwidth = act->ch == L'\0' ? -1 : wcwidth( act->ch );
 
-  Cell *this_cell = fb.get_cell();
+  Cell *this_cell = fb.get_mutable_cell();
 
   Cell *combining_cell = fb.get_combining_cell(); /* can be null if we were resized */
 
@@ -40,7 +40,7 @@ void Emulator::print( Parser::Print *act )
   case 1: /* normal character */
   case 2: /* wide character */
     if ( fb.ds.auto_wrap_mode && fb.ds.next_print_will_wrap ) {
-      fb.get_row( -1 )->wrap = true;
+      fb.get_mutable_row( -1 )->wrap = true;
       fb.ds.move_col( 0 );
       fb.move_rows_autoscroll( 1 );
     }
@@ -50,7 +50,7 @@ void Emulator::print( Parser::Print *act )
 	 && (chwidth == 2)
 	 && (fb.ds.get_cursor_col() == fb.ds.get_width() - 1) ) {
       fb.reset_cell( this_cell );
-      fb.get_row( -1 )->wrap = false;
+      fb.get_mutable_row( -1 )->wrap = false;
       /* There doesn't seem to be a consistent way to get the
 	 downstream terminal emulator to set the wrap-around
 	 copy-and-paste flag on a row that ends with an empty cell
@@ -65,7 +65,7 @@ void Emulator::print( Parser::Print *act )
       }
     }
 
-    this_cell = fb.get_cell();
+    this_cell = fb.get_mutable_cell();
 
     fb.reset_cell( this_cell );
     this_cell->contents.push_back( act->ch );
@@ -74,7 +74,7 @@ void Emulator::print( Parser::Print *act )
 
     if ( chwidth == 2 ) { /* erase overlapped cell */
       if ( fb.ds.get_cursor_col() + 1 < fb.ds.get_width() ) {
-	fb.reset_cell( fb.get_cell( fb.ds.get_cursor_row(), fb.ds.get_cursor_col() + 1 ) );
+	fb.reset_cell( fb.get_mutable_cell( fb.ds.get_cursor_row(), fb.ds.get_cursor_col() + 1 ) );
       }
     }
 
diff --git a/terminal.hpp b/terminal.hpp
index 50400ae..2ff5789 100644
--- a/terminal.hpp
+++ b/terminal.hpp
@@ -32,7 +32,6 @@ namespace Terminal {
     Framebuffer fb;
     Dispatcher dispatch;
     UserInput user;
-    Display display;
 
     /* action methods */
     void print( Parser::Print *act );
@@ -50,7 +49,7 @@ namespace Terminal {
     std::string open( void ); /* put user cursor keys in application mode */
     std::string close( void ); /* restore user cursor keys */
 
-    std::string new_frame( void ) { return display.new_frame( fb ); }
+    const Framebuffer & get_fb( void ) { return fb; }
   };
 }
 
diff --git a/terminaldisplay.cpp b/terminaldisplay.cpp
index 8621df2..fc2a756 100644
--- a/terminaldisplay.cpp
+++ b/terminaldisplay.cpp
@@ -6,15 +6,15 @@ using namespace Terminal;
 
 /* Print a new "frame" to the terminal, using ANSI/ECMA-48 escape codes. */
 
-std::string Display::new_frame( Framebuffer &f )
+std::string Display::new_frame( bool initialized, const Framebuffer &last, const Framebuffer &f )
 {
-  FrameState frame;
+  FrameState frame( last );
 
   char tmp[ 64 ];
 
   /* has window title changed? */
   if ( (!initialized)
-       || (f.get_window_title() != last_frame.get_window_title()) ) {
+       || (f.get_window_title() != frame.last_frame.get_window_title()) ) {
       /* set window title */
     frame.append( "\033]0;[stm] " );
     std::vector<wchar_t> window_title = f.get_window_title();
@@ -29,7 +29,7 @@ std::string Display::new_frame( Framebuffer &f )
 
   /* has reverse video state changed? */
   if ( (!initialized)
-       || (f.ds.reverse_video != last_frame.ds.reverse_video) ) {
+       || (f.ds.reverse_video != frame.last_frame.ds.reverse_video) ) {
     /* set reverse video */
     snprintf( tmp, 64, "\033[?5%c", (f.ds.reverse_video ? 'h' : 'l') );
     frame.append( tmp );
@@ -37,13 +37,17 @@ std::string Display::new_frame( Framebuffer &f )
 
   /* has size changed? */
   if ( (!initialized)
-       || (f.ds.get_width() != last_frame.ds.get_width())
-       || (f.ds.get_height() != last_frame.ds.get_height()) ) {
+       || (f.ds.get_width() != frame.last_frame.ds.get_width())
+       || (f.ds.get_height() != frame.last_frame.ds.get_height()) ) {
     /* clear screen */
     frame.append( "\033[0m\033[H\033[2J" );
     initialized = false;
-    cursor_x = cursor_y = 0;
-    current_rendition_string = "\033[0m";
+    frame.cursor_x = frame.cursor_y = 0;
+    frame.current_rendition_string = "\033[0m";
+  } else {
+    frame.cursor_x = frame.last_frame.ds.get_cursor_col();
+    frame.cursor_y = frame.last_frame.ds.get_cursor_row();
+    frame.current_rendition_string = frame.last_frame.ds.get_renditions().sgr();
   }
 
   /* shortcut -- has display moved up by a certain number of lines? */
@@ -54,7 +58,7 @@ std::string Display::new_frame( Framebuffer &f )
     int scroll_height = 0;
 
     for ( int row = 0; row < f.ds.get_height(); row++ ) {
-      if ( *(f.get_row( 0 )) == *(last_frame.get_row( row )) ) {
+      if ( *(f.get_row( 0 )) == *(frame.last_frame.get_row( row )) ) {
 	/* found a scroll */
 	lines_scrolled = row;
 	scroll_height = 1;
@@ -64,7 +68,7 @@ std::string Display::new_frame( Framebuffer &f )
 	      lines_scrolled + region_height < f.ds.get_height();
 	      region_height++ ) {
 	  if ( *(f.get_row( region_height ))
-	       == *(last_frame.get_row( lines_scrolled + region_height )) ) {
+	       == *(frame.last_frame.get_row( lines_scrolled + region_height )) ) {
 	    scroll_height = region_height + 1;
 	  } else {
 	    break;
@@ -79,17 +83,17 @@ std::string Display::new_frame( Framebuffer &f )
       frame.y = scroll_height;
 
       if ( lines_scrolled ) {
-	if ( cursor_y != f.ds.get_height() - 1 ) {
+	if ( frame.cursor_y != f.ds.get_height() - 1 ) {
 	  snprintf( tmp, 64, "\033[%d;%dH", f.ds.get_height(), 1 );
 	  frame.append( tmp );
 
-	  cursor_y = f.ds.get_height() - 1;
-	  cursor_x = 0;
+	  frame.cursor_y = f.ds.get_height() - 1;
+	  frame.cursor_x = 0;
 	}
 
-	if ( current_rendition_string != "\033[0m" ) {
+	if ( frame.current_rendition_string != "\033[0m" ) {
 	  frame.append( "\033[0m" );
-	  current_rendition_string = "\033[0m";
+	  frame.current_rendition_string = "\033[0m";
 	}
 
 	for ( int i = 0; i < lines_scrolled; i++ ) {
@@ -98,9 +102,9 @@ std::string Display::new_frame( Framebuffer &f )
 
 	for ( int i = 0; i < f.ds.get_height(); i++ ) {
 	  if ( i + lines_scrolled < f.ds.get_height() ) {
-	    *(last_frame.get_row( i )) = *(last_frame.get_row( i + lines_scrolled ));
+	    *(frame.last_frame.get_mutable_row( i )) = *(frame.last_frame.get_row( i + lines_scrolled ));
 	  } else {
-	    last_frame.get_row( i )->reset( 0 );
+	    frame.last_frame.get_mutable_row( i )->reset( 0 );
 	  }
 	}
       }
@@ -113,53 +117,53 @@ std::string Display::new_frame( Framebuffer &f )
     for ( frame.x = 0;
 	  frame.x < f.ds.get_width(); /* let put_cell() handle advance */ ) {
       last_x = frame.x;
-      put_cell( frame, f );
+      put_cell( initialized, frame, f );
 
       /* To hint that a word-select should group the end of one line
 	 with the beginning of the next, we let the real cursor
 	 actually wrap around in cases where it wrapped around for us. */
 
-      if ( (cursor_x >= f.ds.get_width())
+      if ( (frame.cursor_x >= f.ds.get_width())
 	   && (frame.y < f.ds.get_height() - 1)
 	   && f.get_row( frame.y )->wrap
-	   && (!initialized || !last_frame.get_row( frame.y )->wrap) ) {
+	   && (!initialized || !frame.last_frame.get_row( frame.y )->wrap) ) {
 	/* next write will wrap */
-	cursor_x = 0;
-	cursor_y++;
+	frame.cursor_x = 0;
+	frame.cursor_y++;
       }
     }
 
     /* Turn off wrap */
     if ( (frame.y < f.ds.get_height() - 1)
 	 && (!f.get_row( frame.y )->wrap)
-	 && (!initialized || last_frame.get_row( frame.y )->wrap) ) {
+	 && (!initialized || frame.last_frame.get_row( frame.y )->wrap) ) {
       frame.x = last_x;
       if ( initialized ) {
-	last_frame.reset_cell( last_frame.get_cell( frame.y, frame.x ) );
+	frame.last_frame.reset_cell( frame.last_frame.get_mutable_cell( frame.y, frame.x ) );
       }
 
       snprintf( tmp, 64, "\033[%d;%dH\033[K", frame.y + 1, frame.x + 1 );
       frame.append( tmp );
-      cursor_x = frame.x;
+      frame.cursor_x = frame.x;
 
-      put_cell( frame, f );
+      put_cell( initialized, frame, f );
     }
   }
 
   /* has cursor location changed? */
   if ( (!initialized)
-       || (f.ds.get_cursor_row() != cursor_y)
-       || (f.ds.get_cursor_col() != cursor_x) ) {
+       || (f.ds.get_cursor_row() != frame.cursor_y)
+       || (f.ds.get_cursor_col() != frame.cursor_x) ) {
     snprintf( tmp, 64, "\033[%d;%dH", f.ds.get_cursor_row() + 1,
 	      f.ds.get_cursor_col() + 1 );
     frame.append( tmp );
-    cursor_x = f.ds.get_cursor_col();
-    cursor_y = f.ds.get_cursor_row();
+    frame.cursor_x = f.ds.get_cursor_col();
+    frame.cursor_y = f.ds.get_cursor_row();
   }
 
   /* has cursor visibility changed? */
   if ( (!initialized)
-       || (f.ds.cursor_visible != last_frame.ds.cursor_visible) ) {
+       || (f.ds.cursor_visible != frame.last_frame.ds.cursor_visible) ) {
     if ( f.ds.cursor_visible ) {
       frame.append( "\033[?25h" );
     } else {
@@ -167,44 +171,48 @@ std::string Display::new_frame( Framebuffer &f )
     }
   }
 
-  last_frame = f;
-  initialized = true;
+  /* have renditions changed? */
+  if ( (!initialized)
+       || (f.ds.get_renditions().sgr() != frame.current_rendition_string) ) {
+    frame.append( f.ds.get_renditions().sgr() );
+    frame.current_rendition_string = f.ds.get_renditions().sgr();
+  }
 
   return frame.str;
 }
 
-void Display::put_cell( FrameState &frame, Framebuffer &f )
+void Display::put_cell( bool initialized, FrameState &frame, const Framebuffer &f )
 {
   char tmp[ 64 ];
 
-  Cell *cell = f.get_cell( frame.y, frame.x );
+  const Cell *cell = f.get_cell( frame.y, frame.x );
 
   if ( initialized
-       && ( *cell == *(last_frame.get_cell( frame.y, frame.x )) ) ) {
+       && ( *cell == *(frame.last_frame.get_cell( frame.y, frame.x )) ) ) {
     frame.x += cell->width;
     return;
   }
 
-  if ( (frame.x != cursor_x) || (frame.y != cursor_y) ) {
+  if ( (frame.x != frame.cursor_x) || (frame.y != frame.cursor_y) ) {
     snprintf( tmp, 64, "\033[%d;%dH", frame.y + 1, frame.x + 1 );
     frame.append( tmp );
-    cursor_x = frame.x;
-    cursor_y = frame.y;
+    frame.cursor_x = frame.x;
+    frame.cursor_y = frame.y;
   }
 
   std::string rendition_str = cell->renditions.sgr();
 
-  if ( current_rendition_string != rendition_str ) {
+  if ( frame.current_rendition_string != rendition_str ) {
     /* print renditions */
     frame.append( rendition_str );
-    current_rendition_string = rendition_str;
+    frame.current_rendition_string = rendition_str;
   }
 
   if ( cell->contents.empty() ) {
     /* see how far we can stretch a clear */
     int clear_count = 0;
     for ( int col = frame.x; col < f.ds.get_width(); col++ ) {
-      Cell *other_cell = f.get_cell( frame.y, col );
+      const Cell *other_cell = f.get_cell( frame.y, col );
       if ( (cell->renditions == other_cell->renditions)
 	   && (other_cell->contents.empty()) ) {
 	clear_count++;
@@ -225,7 +233,7 @@ void Display::put_cell( FrameState &frame, Framebuffer &f )
     frame.append( tmp );
   }
 
-  for ( std::vector<wchar_t>::iterator i = cell->contents.begin();
+  for ( std::vector<wchar_t>::const_iterator i = cell->contents.begin();
 	i != cell->contents.end();
 	i++ ) {
     snprintf( tmp, 64, "%lc", *i );
@@ -233,5 +241,5 @@ void Display::put_cell( FrameState &frame, Framebuffer &f )
   }
 
   frame.x += cell->width;
-  cursor_x += cell->width;
+  frame.cursor_x += cell->width;
 }
diff --git a/terminaldisplay.hpp b/terminaldisplay.hpp
index dae7bcc..1014751 100644
--- a/terminaldisplay.hpp
+++ b/terminaldisplay.hpp
@@ -10,27 +10,23 @@ namespace Terminal {
     int x, y;
     std::string str;
 
-    FrameState() : x(0), y(0), str() {}
+    int cursor_x, cursor_y;
+    std::string current_rendition_string;
+
+    Framebuffer last_frame;
+
+    FrameState( const Framebuffer &s_last ) : x(0), y(0), str(), cursor_x(0), cursor_y(0), current_rendition_string(), last_frame( s_last ) {}
     void append( std::string s ) { str.append( s ); }
   };
 
   class Display {
   private:
-    bool initialized;
-    Framebuffer last_frame;
-    std::string current_rendition_string;
-    int cursor_x, cursor_y;
-
-    void put_cell( FrameState &frame, Framebuffer &f );
+    void put_cell( bool initialized, FrameState &frame, const Framebuffer &f );
 
   public:
-    Display( int width, int height )
-      : initialized( false ), last_frame( width, height ),
-	current_rendition_string(), cursor_x( -1 ), cursor_y( -1 )
-    {}
+    Display() {}
 
-    std::string new_frame( Framebuffer &f );
-    void invalidate( void ) { initialized = false; }
+    std::string new_frame( bool initialized, const Framebuffer &last, const Framebuffer &f );
   };
 }
 
diff --git a/terminalframebuffer.cpp b/terminalframebuffer.cpp
index 2e6335e..f67b380 100644
--- a/terminalframebuffer.cpp
+++ b/terminalframebuffer.cpp
@@ -199,7 +199,7 @@ std::vector<int> DrawState::get_tabs( void )
 
 void Framebuffer::apply_renditions_to_current_cell( void )
 {
-  get_cell()->renditions = ds.get_renditions();
+  get_mutable_cell()->renditions = ds.get_renditions();
 }
 
 SavedCursor::SavedCursor()
@@ -373,7 +373,7 @@ void Renditions::set_rendition( int num )
   }
 }
 
-std::string Renditions::sgr( void )
+std::string Renditions::sgr( void ) const
 {
   std::string ret;
 
diff --git a/terminalframebuffer.hpp b/terminalframebuffer.hpp
index a5f9e85..4a99f27 100644
--- a/terminalframebuffer.hpp
+++ b/terminalframebuffer.hpp
@@ -18,7 +18,7 @@ namespace Terminal {
 
     Renditions( int s_background );
     void set_rendition( int num );
-    std::string sgr( void );
+    std::string sgr( void ) const;
 
     bool operator==( const Renditions &x ) const
     {
@@ -119,12 +119,12 @@ namespace Terminal {
     void move_row( int N, bool relative = false );
     void move_col( int N, bool relative = false, bool implicit = false );
 
-    int get_cursor_col( void ) { return cursor_col; }
-    int get_cursor_row( void ) { return cursor_row; }
-    int get_combining_char_col( void ) { return combining_char_col; }
-    int get_combining_char_row( void ) { return combining_char_row; }
-    int get_width( void ) { return width; }
-    int get_height( void ) { return height; }
+    int get_cursor_col( void ) const { return cursor_col; }
+    int get_cursor_row( void ) const { return cursor_row; }
+    int get_combining_char_col( void ) const { return combining_char_col; }
+    int get_combining_char_row( void ) const { return combining_char_row; }
+    int get_width( void ) const { return width; }
+    int get_height( void ) const { return height; }
 
     void set_tab( void );
     void clear_tab( int col );
@@ -134,14 +134,14 @@ namespace Terminal {
 
     void set_scrolling_region( int top, int bottom );
 
-    int get_scrolling_region_top_row( void ) { return scrolling_region_top_row; }
-    int get_scrolling_region_bottom_row( void ) { return scrolling_region_bottom_row; }
+    int get_scrolling_region_top_row( void ) const { return scrolling_region_top_row; }
+    int get_scrolling_region_bottom_row( void ) const { return scrolling_region_bottom_row; }
 
     int limit_top( void );
     int limit_bottom( void );
 
     void add_rendition( int x ) { renditions.set_rendition( x ); }
-    Renditions get_renditions( void ) { return renditions; }
+    Renditions get_renditions( void ) const { return renditions; }
     int get_background_rendition( void ) { return renditions.background_color; }
 
     void save_cursor( void );
@@ -167,36 +167,42 @@ namespace Terminal {
     void scroll( int N );
     void move_rows_autoscroll( int rows );
 
-    Row *get_row( int row )
+    const Row *get_row( int row ) const
     {
       if ( row == -1 ) row = ds.get_cursor_row();
 
       return &rows[ row ];
     }
 
-    inline Cell *get_cell( void )
+    inline const Cell *get_cell( void ) const
     {
-#ifdef DEBUG
-      assert( ds.get_cursor_row() >= 0 );
-      assert( ds.get_cursor_col() >= 0 );
-      assert( ds.get_cursor_row() < ds.get_height() );
-      assert( ds.get_cursor_col() < ds.get_width() );
-#endif
-
       return &rows[ ds.get_cursor_row() ].cells[ ds.get_cursor_col() ];
     }
 
-    inline Cell *get_cell( int row, int col )
+    inline const Cell *get_cell( int row, int col ) const
     {
       if ( row == -1 ) row = ds.get_cursor_row();
       if ( col == -1 ) col = ds.get_cursor_col();
 
-#ifdef DEBUG
-      assert( row >= 0 );
-      assert( col >= 0 );
-      assert( row < ds.get_height() );
-      assert( col < ds.get_width() );
-#endif
+      return &rows[ row ].cells[ col ];
+    }
+
+    Row *get_mutable_row( int row )
+    {
+      if ( row == -1 ) row = ds.get_cursor_row();
+
+      return &rows[ row ];
+    }
+
+    inline Cell *get_mutable_cell( void )
+    {
+      return &rows[ ds.get_cursor_row() ].cells[ ds.get_cursor_col() ];
+    }
+
+    inline Cell *get_mutable_cell( int row, int col )
+    {
+      if ( row == -1 ) row = ds.get_cursor_row();
+      if ( col == -1 ) col = ds.get_cursor_col();
 
       return &rows[ row ].cells[ col ];
     }
@@ -215,7 +221,7 @@ namespace Terminal {
     void soft_reset( void );
 
     void set_window_title( std::vector<wchar_t> s ) { window_title = s; }
-    std::vector<wchar_t> get_window_title( void ) { return window_title; }
+    std::vector<wchar_t> get_window_title( void ) const { return window_title; }
 
     void resize( int s_width, int s_height );
 
diff --git a/terminalfunctions.cpp b/terminalfunctions.cpp
index 5d860d2..7d9c464 100644
--- a/terminalfunctions.cpp
+++ b/terminalfunctions.cpp
@@ -12,7 +12,7 @@ using namespace Terminal;
 static void clearline( Framebuffer *fb, int row, int start, int end )
 {
   for ( int col = start; col <= end; col++ ) {
-    fb->reset_cell( fb->get_cell( row, col ) );
+    fb->reset_cell( fb->get_mutable_cell( row, col ) );
   }
 }
 
@@ -27,7 +27,7 @@ void CSI_EL( Framebuffer *fb, Dispatcher *dispatch )
     clearline( fb, -1, 0, fb->ds.get_cursor_col() );
     break;
   case 2: /* all of line */
-    fb->reset_row( fb->get_row( -1 ) );
+    fb->reset_row( fb->get_mutable_row( -1 ) );
     break;
   }
 }
@@ -40,18 +40,18 @@ void CSI_ED( Framebuffer *fb, Dispatcher *dispatch ) {
   case 0: /* active position to end of screen, inclusive */
     clearline( fb, -1, fb->ds.get_cursor_col(), fb->ds.get_width() - 1 );
     for ( int y = fb->ds.get_cursor_row() + 1; y < fb->ds.get_height(); y++ ) {
-      fb->reset_row( fb->get_row( y ) );
+      fb->reset_row( fb->get_mutable_row( y ) );
     }
     break;
   case 1: /* start of screen to active position, inclusive */
     for ( int y = 0; y < fb->ds.get_cursor_row(); y++ ) {
-      fb->reset_row( fb->get_row( y ) );
+      fb->reset_row( fb->get_mutable_row( y ) );
     }
     clearline( fb, -1, 0, fb->ds.get_cursor_col() );
     break;
   case 2: /* entire screen */
     for ( int y = 0; y < fb->ds.get_height(); y++ ) {
-      fb->reset_row( fb->get_row( y ) );
+      fb->reset_row( fb->get_mutable_row( y ) );
     }
     break;
   }
@@ -114,8 +114,8 @@ void Esc_DECALN( Framebuffer *fb, Dispatcher *dispatch __attribute((unused)) )
 {
   for ( int y = 0; y < fb->ds.get_height(); y++ ) {
     for ( int x = 0; x < fb->ds.get_width(); x++ ) {
-      fb->reset_cell( fb->get_cell( y, x ) );
-      fb->get_cell( y, x )->contents.push_back( L'E' );
+      fb->reset_cell( fb->get_mutable_cell( y, x ) );
+      fb->get_mutable_cell( y, x )->contents.push_back( L'E' );
     }
   }
 }
@@ -215,7 +215,7 @@ static bool *get_DEC_mode( int param, Framebuffer *fb ) {
     fb->ds.move_row( 0 );
     fb->ds.move_col( 0 );
     for ( int y = 0; y < fb->ds.get_height(); y++ ) {
-      fb->reset_row( fb->get_row( y ) );
+      fb->reset_row( fb->get_mutable_row( y ) );
     }
     return NULL;
   case 5: /* reverse video */