Better speculative local echo/editing. Also outputs debugging/timing info

networktransport.hpp

@@ -79,6 +79,9 @@ namespace Network {
     void set_verbose( void ) { sender.set_verbose(); verbose = true; }
 
     void set_send_delay( int new_delay ) { sender.set_send_delay( new_delay ); }
+
+    uint64_t get_sent_state_acked( void ) { return sender.get_sent_state_acked(); }
+    uint64_t get_sent_state_last( void ) { return sender.get_sent_state_last(); }
   };
 }
 

parser.cpp

@@ -39,11 +39,6 @@ std::list<Parser::Action *> Parser::Parser::input( wchar_t ch )
 Parser::UTF8Parser::UTF8Parser()
   : parser(), buf_len( 0 )
 {
-  if ( strcmp( nl_langinfo( CODESET ), "UTF-8" ) != 0 ) {
-    fprintf( stderr, "stm requires a UTF-8 locale.\n" );
-    throw std::string( "stm requires a UTF-8 locale." );
-  }
-
   assert( BUF_SIZE >= MB_CUR_MAX );
 }
 

stm.cpp

@@ -28,7 +28,7 @@ int main( int argc, char *argv[] )
   client.main();
 
   client.shutdown();
-  printf( "\n[stm is exiting.]\n" );
+  printf( "\n[mosh is exiting.]\n" );
 
   return 0;
 }

stmclient.cpp

@@ -24,7 +24,7 @@ void STMClient::init( void )
 {
   /* Verify locale calls for UTF-8 */
   if ( strcmp( nl_langinfo( CODESET ), "UTF-8" ) != 0 ) {
-    fprintf( stderr, "stm requires a UTF-8 locale.\n" );
+    fprintf( stderr, "mosh requires a UTF-8 locale.\n" );
     exit( 1 );
   }
 
@@ -50,10 +50,19 @@ void STMClient::init( void )
 
   /* Put terminal in application-cursor-key mode */
   swrite( STDOUT_FILENO, Terminal::Emulator::open().c_str() );
+
+  /* Add our name to window title */
+  overlays.set_title_prefix( wstring( L"[mosh] " ) );
 }
 
 void STMClient::shutdown( void )
 {
+  /* Restore screen state */
+  overlays.get_notification_engine().set_notification_string( wstring( L"" ) );
+  overlays.get_notification_engine().server_heard( timestamp() );
+  overlays.set_title_prefix( wstring( L"" ) );
+  output_new_frame();
+
   /* Restore terminal and terminal-driver state */
   swrite( STDOUT_FILENO, Terminal::Emulator::close().c_str() );
   
@@ -126,7 +135,6 @@ void STMClient::output_new_frame( void )
   Terminal::Framebuffer new_state( network->get_latest_remote_state().state.get_fb() );
 
   /* apply local overlays */
-  overlays.get_notification_engine().render_notification();
   overlays.apply( new_state );
 
   /* calculate minimal difference from where we are */
@@ -143,7 +151,9 @@ bool STMClient::process_network_input( void )
 {
   network->recv();
   
-  overlays.get_notification_engine().server_ping( network->get_latest_remote_state().timestamp );
+  overlays.get_notification_engine().server_heard( network->get_latest_remote_state().timestamp );
+
+  overlays.get_prediction_engine().set_local_frame_acked( network->get_sent_state_acked() );
 
   return true;
 }
@@ -163,6 +173,8 @@ bool STMClient::process_user_input( int fd )
   }
 
   if ( !network->shutdown_in_progress() ) {
+    overlays.get_prediction_engine().set_local_frame_sent( network->get_sent_state_last() );
+
     for ( int i = 0; i < bytes_read; i++ ) {
       char the_byte = buf[ i ];
 
@@ -232,6 +244,9 @@ bool STMClient::process_resize( void )
     i->state.act( &res );
   }
 
+  /* tell prediction engine */
+  overlays.get_prediction_engine().reset();
+
   return true;
 }
 

terminaldisplay.cpp

@@ -17,8 +17,8 @@ std::string Display::new_frame( bool initialized, const Framebuffer &last, const
        || (f.get_window_title() != frame.last_frame.get_window_title()) ) {
       /* set window title */
     frame.append( "\033]0;" );
-    std::vector<wchar_t> window_title = f.get_window_title();
+    const std::deque<wchar_t> &window_title( f.get_window_title() );
-    for ( std::vector<wchar_t>::iterator i = window_title.begin();
+    for ( auto i = window_title.begin();
 	  i != window_title.end();
 	  i++ ) {
       snprintf( tmp, 64, "%lc", *i );

terminalframebuffer.cpp

@@ -406,3 +406,19 @@ void Row::reset( int background_color )
     i->reset( background_color );
   }
 }
+
+void Framebuffer::prefix_window_title( const std::deque<wchar_t> &s )
+{
+  for ( 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();
+  }
+}

terminalframebuffer.hpp

@@ -61,6 +61,8 @@ namespace Terminal {
 	       && (width == x.width)
 	       && (renditions == x.renditions) );
     }
+
+    wchar_t debug_contents( void ) const;
   };
 
   class Row {
@@ -179,7 +181,7 @@ namespace Terminal {
   class Framebuffer {
   private:
     std::deque<Row> rows;
-    std::vector<wchar_t> window_title;
+    std::deque<wchar_t> window_title;
 
     Row newrow( void ) { return Row( ds.get_width(), ds.get_background_rendition() ); }
 
@@ -243,8 +245,10 @@ namespace Terminal {
     void reset( void );
     void soft_reset( void );
 
-    void set_window_title( std::vector<wchar_t> s ) { window_title = s; }
+    void set_window_title( const std::deque<wchar_t> &s ) { window_title = s; }
-    std::vector<wchar_t> get_window_title( void ) const { return window_title; }
+    const std::deque<wchar_t> & get_window_title( void ) const { return window_title; }
+
+    void prefix_window_title( const std::deque<wchar_t> &s );
 
     void resize( int s_width, int s_height );
 

terminalfunctions.cpp

@@ -466,7 +466,7 @@ void Dispatcher::OSC_dispatch( const Parser::OSC_End *act, Framebuffer *fb )
   if ( OSC_string.size() >= 2 ) {
     if ( (OSC_string[ 0 ] == L'0')
 	 && (OSC_string[ 1 ] == L';') ) {
-      std::vector<wchar_t> newtitle = OSC_string;
+      std::deque<wchar_t> newtitle( OSC_string.begin(), OSC_string.end() );
       newtitle.erase( newtitle.begin() );
       newtitle.erase( newtitle.begin() );
       fb->set_window_title( newtitle );

terminaloverlay.cpp

@@ -8,28 +8,41 @@
 
 using namespace Overlay;
 
-Validity OverlayElement::get_validity( const Framebuffer & ) const
+void ConditionalOverlayCell::apply( Framebuffer &fb, bool show_tentative, int row, bool flag ) const
 {
-  return (timestamp() < expiration_time) ? Pending : IncorrectOrExpired;
+  if ( (!active)
-}
+       || (row >= fb.ds.get_height())
-
-void OverlayCell::apply( Framebuffer &fb ) const
-{
-  if ( (row >= fb.ds.get_height())
        || (col >= fb.ds.get_width()) ) {
     return;
   }
 
-  if ( !(*(fb.get_mutable_cell( row, col )) == replacement) ) {
+  if ( tentative && (!show_tentative) ) {
+    return;
+  }
+
+  /*
+  fprintf( stderr, "APPLYING char %lc to (%d, %d)\n",
+	   replacement.debug_contents(), row, col );
+  */
+
+  if ( !(*(fb.get_cell( row, col )) == replacement) ) {
     *(fb.get_mutable_cell( row, col )) = replacement;
+    uint64_t now = timestamp();
+    if ( display_time >= now ) {
+      display_time = now;
+    }
     if ( flag ) {
       fb.get_mutable_cell( row, col )->renditions.underlined = true;
     }
   }
 }
 
-Validity ConditionalOverlayCell::get_validity( const Framebuffer &fb ) const
+Validity ConditionalOverlayCell::get_validity( const Framebuffer &fb, int row, uint64_t current_frame ) const
 {
+  if ( !active ) {
+    return Inactive;
+  }
+
   if ( (row >= fb.ds.get_height())
        || (col >= fb.ds.get_width()) ) {
     return IncorrectOrExpired;
@@ -37,10 +50,16 @@ Validity ConditionalOverlayCell::get_validity( const Framebuffer &fb ) const
 
   const Cell &current = *( fb.get_cell( row, col ) );
 
-  if ( (timestamp() < expiration_time) && (current == original_contents) ) {
+  /* see if it hasn't been updated yet */
+  if ( (current_frame < expiration_frame) ) {
     return Pending;
   }
 
+  /* special case deletion */
+  if ( current.contents.empty() && (replacement.contents.size() == 1) && (replacement.contents.front() == 0x20) ) {
+    return Correct;
+  }
+
   if ( current == replacement ) {
     return Correct;
   } else {
@@ -48,224 +67,76 @@ Validity ConditionalOverlayCell::get_validity( const Framebuffer &fb ) const
   }
 }
 
-void CursorMove::apply( Framebuffer &fb ) const
+Validity ConditionalCursorMove::get_validity( const Framebuffer &fb, uint64_t current_frame ) const
 {
-  assert( new_row < fb.ds.get_height() );
+  if ( !active ) {
-  assert( new_col < fb.ds.get_width() );
+    return Inactive;
+  }
+
+  if ( (row >= fb.ds.get_height())
+       || (col >= fb.ds.get_width()) ) {
+    fprintf( stderr, "Crazy cursor (%d,%d)!\n", row, col );
+    return IncorrectOrExpired;
+  }
+
+  if ( (fb.ds.get_cursor_col() == col)
+       && (fb.ds.get_cursor_row() == row) ) {
+    return Correct;
+  } else if ( current_frame < expiration_frame ) {
+    return Pending;
+  } else {
+
+    fprintf( stderr, "Bad cursor in %d (i thought %d vs %d).\n", (int)current_frame,
+    	     col, fb.ds.get_cursor_col() );
+    return IncorrectOrExpired;
+  }
+}
+
+void ConditionalCursorMove::apply( Framebuffer &fb ) const
+{
+  if ( !active ) {
+    return;
+  }
+
+  int target_row = row;
+  int target_col = col;
+
+  if ( show_frozen_cursor ) {
+    target_row = frozen_row;
+    target_col = frozen_col;
+  }
+
+  assert( target_row < fb.ds.get_height() );
+  assert( target_col < fb.ds.get_width() );
   assert( !fb.ds.origin_mode );
 
-  fb.ds.move_row( new_row, false );
+  fb.ds.move_row( target_row, false );
-  fb.ds.move_col( new_col, false, false );
+  fb.ds.move_col( target_col, false, false );
 }
 
-Validity ConditionalCursorMove::get_validity( const Framebuffer &fb ) const
-{
-  if ( (new_row >= fb.ds.get_height())
-       || (new_col >= fb.ds.get_width()) ) {
-    return IncorrectOrExpired;
-  }
-
-  if ( timestamp() < expiration_time ) {
-    return Pending;
-  }
-
-  if ( (fb.ds.get_cursor_col() == new_col)
-       && (fb.ds.get_cursor_row() == new_row) ) {
-    return Correct;
-  } else {
-    return IncorrectOrExpired;
-  }
-}
-
-void OverlayEngine::clear( void )
-{
-  for_each( elements.begin(), elements.end(), []( OverlayElement *x ){ delete x; } );
-  elements.clear();
-}
-
-OverlayEngine::~OverlayEngine()
-{
-  clear();
-}
-
-void OverlayEngine::apply( Framebuffer &fb ) const
-{
-  for_each( elements.begin(), elements.end(),
-	    [&fb]( OverlayElement *x ) { x->apply( fb ); } );
-}
-
-void PredictionEngine::cull( const Framebuffer &fb )
-{
-  uint64_t now = timestamp();
-
-  auto i = elements.begin();
-  while ( i != elements.end() ) {
-    /* update echo timeout state */
-    if ( (typeid( ConditionalOverlayCell ) == typeid( **i ))
-	 && ((*i)->get_validity( fb ) == Correct) ) {
-      double R = now - (*i)->prediction_time;
-      if ( !RTT_hit ) { /* first measurement */
-	SRTT = R;
-	RTTVAR = R / 2;
-	RTT_hit = true;
-      } else {
-	const double alpha = 1.0 / 32.0;
-	const double beta = 1.0 / 16.0;
-	
-	RTTVAR = (1 - beta) * RTTVAR + ( beta * fabs( SRTT - R ) );
-	SRTT = (1 - alpha) * SRTT + ( alpha * R );
-      }
-    }
-
-    /* eliminate predictions proven correct or incorrect */
-    if ( (*i)->get_validity( fb ) != Pending ) {
-      delete (*i);
-      i = elements.erase( i );
-    } else {
-      i++;
-    }
-  }
-
-  if ( SRTT > 150 ) flagging = true; /* start underlining predicted chars */
-  if ( SRTT + 4 * RTTVAR < 100 ) flagging = false; /* use some hysterisis to avoid flapping */
-}
-
-OverlayCell::OverlayCell( uint64_t expiration_time, int s_row, int s_col, int background_color )
-  : OverlayElement( expiration_time ), row( s_row ), col( s_col ), replacement( background_color )
-{}
-
-CursorMove::CursorMove( uint64_t expiration_time, int s_new_row, int s_new_col )
-  : OverlayElement( expiration_time ), new_row( s_new_row ), new_col( s_new_col )
-{}
-
 NotificationEngine::NotificationEngine()
-  : needs_render( true ),
+  : last_word_from_server( timestamp() ),
-    last_word( timestamp() ),
-    last_render( 0 ),
     message(),
-    message_expiration( 0 )
+    message_expiration( -1 )
 {}
 
-void NotificationEngine::server_ping( uint64_t s_last_word )
-{
-  if ( s_last_word - last_word > 4000 ) {
-    needs_render = true;
-  }
-
-  last_word = s_last_word;
-}
-
-void NotificationEngine::set_notification_string( const wstring s_message )
-{
-  message = s_message;
-  message_expiration = timestamp() + 1100;
-  needs_render = true;
-}
-
-void NotificationEngine::render_notification( void )
-{
-  uint64_t now = timestamp();
-
-  if ( (now - last_render < 250) && (!needs_render) ) {
-    return;
-  }
-
-  needs_render = false;
-  last_render = now;
-
-  clear();
-
-  /* determine string to draw */
-  if ( now >= message_expiration ) {
-    message.clear();
-  }
-
-  bool time_expired = now - last_word > 5000;
-
-  wchar_t tmp[ 128 ];
-
-  if ( message.empty() && (!time_expired) ) {
-    return;
-  } else if ( message.empty() && time_expired ) {
-    swprintf( tmp, 128, L"[stm] Last contact %.0f seconds ago. [To quit: Ctrl-^ .]", (double)(now - last_word) / 1000.0 );
-  } else if ( (!message.empty()) && (!time_expired) ) {
-    swprintf( tmp, 128, L"[stm] %ls [To quit: Ctrl-^ .]", message.c_str() );
-  } else {
-    swprintf( tmp, 128, L"[stm] %ls (%.0f s without contact.) [To quit: Ctrl-^ .]", message.c_str(),
-	      (double)(now - last_word) / 1000.0 );
-  }
-
-  wstring string_to_draw( tmp );
-
-  int overlay_col = 0;
-  bool dirty = false;
-  OverlayCell template_cell( now + 1100, 0 /* row */, -1 /* col */, 0 /* background_color */ );
-
-  template_cell.replacement.renditions.bold = true;
-  template_cell.replacement.renditions.foreground_color = 37;
-  template_cell.replacement.renditions.background_color = 44;
-
-  OverlayCell current( template_cell );
-
-  for ( wstring::const_iterator i = string_to_draw.begin(); i != string_to_draw.end(); i++ ) {
-    wchar_t ch = *i;
-    int chwidth = ch == L'\0' ? -1 : wcwidth( ch );
-
-    switch ( chwidth ) {
-    case 1: /* normal character */
-    case 2: /* wide character */
-      /* finish current cell */
-      if ( dirty ) {
-	elements.push_back( new OverlayCell( current ) );
-	dirty = false;
-      }
-      
-      /* initialize new cell */
-      current = template_cell;
-      current.col = overlay_col;
-      current.replacement.contents.push_back( ch );
-      current.replacement.width = chwidth;
-      overlay_col += chwidth;
-      dirty = true;
-      break;
-
-    case 0: /* combining character */
-      if ( current.replacement.contents.empty() ) {
-	/* string starts with combining character?? */
-	/* emulate fallback rendering */
-	current = template_cell;
-	current.col = overlay_col;
-	current.replacement.contents.push_back( 0xA0 ); /* no-break space */
-	current.replacement.width = 1;
-	overlay_col++;
-	dirty = true;
-      }
-
-      current.replacement.contents.push_back( ch );
-      break;
-
-    case -1:
-      break;
-      
-    default:
-      assert( false );
-    }
-  }
-
-  if ( dirty ) {
-    elements.push_back( new OverlayCell( current ) );
-  }
-}
-
 void NotificationEngine::apply( Framebuffer &fb ) const
 {
-  if ( elements.empty() ) {
+  uint64_t now = timestamp();
+
+  bool time_expired = need_countup( now );
+
+  if ( message.empty() && !time_expired ) {
     return;
   }
 
   assert( fb.ds.get_width() > 0 );
   assert( fb.ds.get_height() > 0 );
 
+  /* hide cursor if necessary */
+  if ( fb.ds.get_cursor_row() == 0 ) {
+    fb.ds.cursor_visible = false;
+  }
 
   /* draw bar across top of screen */
   Cell notification_bar( 0 );
@@ -277,135 +148,356 @@ void NotificationEngine::apply( Framebuffer &fb ) const
     *(fb.get_mutable_cell( 0, i )) = notification_bar;
   }
 
-  /* hide cursor if necessary */
+  /* write message */
-  if ( fb.ds.get_cursor_row() == 0 ) {
+  wchar_t tmp[ 128 ];
-    fb.ds.cursor_visible = false;
+
+  if ( message.empty() && (!time_expired) ) {
+    return;
+  } else if ( message.empty() && time_expired ) {
+    swprintf( tmp, 128, L"mosh: Last contact %.0f seconds ago. [To quit: Ctrl-^ .]", (double)(now - last_word_from_server) / 1000.0 );
+  } else if ( (!message.empty()) && (!time_expired) ) {
+    swprintf( tmp, 128, L"mosh: %ls [To quit: Ctrl-^ .]", message.c_str() );
+  } else {
+    swprintf( tmp, 128, L"mosh: %ls (%.0f s without contact.) [To quit: Ctrl-^ .]", message.c_str(),
+	      (double)(now - last_word_from_server) / 1000.0 );
   }
 
-  OverlayEngine::apply( fb );
+  wstring string_to_draw( tmp );
+
+  int overlay_col = 0;
+
+  Cell *combining_cell = fb.get_mutable_cell( 0, 0 );
+
+  /* We unfortunately duplicate the terminal's logic for how to render a Unicode sequence into graphemes */
+  for ( wstring::const_iterator i = string_to_draw.begin(); i != string_to_draw.end(); i++ ) {
+    if ( overlay_col >= fb.ds.get_width() ) {
+      break;
+    }
+
+    wchar_t ch = *i;
+    int chwidth = ch == L'\0' ? -1 : wcwidth( ch );
+    Cell *this_cell = nullptr;
+
+    switch ( chwidth ) {
+    case 1: /* normal character */
+    case 2: /* wide character */
+      this_cell = fb.get_mutable_cell( 0, overlay_col );
+      fb.reset_cell( this_cell );
+      this_cell->renditions.bold = true;
+      this_cell->renditions.foreground_color = 37;
+      this_cell->renditions.background_color = 44;
+      
+      this_cell->contents.push_back( ch );
+      this_cell->width = chwidth;
+      combining_cell = this_cell;
+
+      overlay_col += chwidth;
+      break;
+    case 0: /* combining character */
+      if ( !combining_cell ) {
+	break;
+      }
+
+      if ( combining_cell->contents.size() == 0 ) {
+	assert( combining_cell->width == 1 );
+	combining_cell->fallback = true;
+	overlay_col++;
+      }
+
+      if ( combining_cell->contents.size() < 16 ) {
+	combining_cell->contents.push_back( ch );
+      }
+      break;
+    case -1: /* unprintable character */
+      break;
+    default:
+      assert( false );
+    }
+  }
+}
+
+void NotificationEngine::adjust_message( void )
+{
+  if ( timestamp() >= message_expiration ) {
+    message.clear();
+  }  
 }
 
 void OverlayManager::apply( Framebuffer &fb )
 {
-  predictions.calculate_score( fb );
-
-  /* eliminate predictions proven correct or incorrect and update echo timers */
   predictions.cull( fb );
-
+  predictions.apply( fb );
-  if ( predictions.get_score() > 3 ) {
+  notifications.adjust_message();
-    predictions.apply( fb );
-  }
-
   notifications.apply( fb );
+  title.apply( fb );
 }
 
-void PredictionEngine::calculate_score( const Framebuffer &fb )
+int OverlayManager::wait_time( void )
 {
-  for ( auto i = begin(); i != end(); i++ ) {
+  uint64_t next_expiry = INT_MAX;
-    switch( (*i)->get_validity( fb ) ) {
+
-    case Pending:
+  uint64_t message_delay = notifications.get_message_expiration() - timestamp();
-      break;
+
-    case Correct:
+  if ( message_delay < next_expiry ) {
-      score++;
+    next_expiry = message_delay;
-      break;
+  }
-    case IncorrectOrExpired:
+
-      score = 0;
+  if ( notifications.need_countup( timestamp() ) && ( next_expiry > 1000 ) ) {
-      clear();
+    next_expiry = 1000;
-      return;
+  }
+
+  return next_expiry;
+}
+
+void TitleEngine::set_prefix( const wstring s )
+{
+  prefix = deque<wchar_t>( s.begin(), s.end() );
+}
+
+void ConditionalOverlayRow::apply( Framebuffer &fb, bool show_tentative, bool flag ) const
+{
+  for_each( overlay_cells.begin(), overlay_cells.end(), [&]( const ConditionalOverlayCell &x ) { x.apply( fb, show_tentative, row_num, flag ); } );
+}
+
+void PredictionEngine::apply( Framebuffer &fb ) const
+{
+  if ( (score > 0) || cursor.show_frozen_cursor ) {
+    cursor.apply( fb );
+  }
+  for_each( overlays.begin(), overlays.end(), [&]( const ConditionalOverlayRow &x ){ x.apply( fb, score > 0, flagging ); } );
+}
+
+void PredictionEngine::reset( void )
+{
+  overlays.clear();
+  cursor.reset();
+  become_tentative();
+}
+
+void PredictionEngine::cull( const Framebuffer &fb )
+{
+  if ( score > 0 ) {
+    cursor.thaw();
+  }
+
+  uint64_t now = timestamp();
+
+  /* don't increment score just for correct cursor position */
+  switch ( cursor.get_validity( fb, local_frame_acked) ) {
+  case IncorrectOrExpired:
+    cursor.reset();
+    become_tentative();
+    return;
+    break;
+  default:
+    break;
+  }
+
+  uint64_t max_delay = 0;
+
+  auto i = overlays.begin();
+  while ( i != overlays.end() ) {
+    auto inext = i;
+    inext++;
+    if ( (i->row_num < 0) || (i->row_num >= fb.ds.get_height()) ) {
+      overlays.erase( i );
+      i = inext;
+      continue;
     }
+
+    for ( auto j = i->overlay_cells.begin(); j != i->overlay_cells.end(); j++ ) {
+      switch ( j->get_validity( fb, i->row_num, local_frame_acked ) ) {
+      case IncorrectOrExpired:
+	if ( j->tentative ) {
+	  fprintf( stderr, "Bad tentative prediction in row %d, col %d (thought %lc, was %lc)\n",
+		   i->row_num, j->col,
+		   j->replacement.debug_contents(), fb.get_cell( i->row_num, j->col )->debug_contents() );
+	  j->reset();
+	  become_tentative();
+	  if ( j->display_time != uint64_t(-1) ) {
+	    fprintf( stderr, "TIMING %ld - %ld (TENT)\n", time(NULL), now - j->display_time );
+	  }
+	} else {
+	  fprintf( stderr, "[%d=>%d] (score=%d) Killing prediction in row %d, col %d (thought %lc, was %lc)\n",
+		   (int)local_frame_acked, (int)j->expiration_frame,
+		   score,
+		   i->row_num, j->col,
+		   j->replacement.debug_contents(), fb.get_cell( i->row_num, j->col )->debug_contents() );
+	  reset();
+	  if ( j->display_time != uint64_t(-1) ) {
+	    fprintf( stderr, "TIMING %ld - %ld\n", time(NULL), now - j->display_time );
+	  }
+	  return;
+	}
+	break;
+      case Correct:
+	if ( j->display_time != uint64_t(-1) ) {
+	  fprintf( stderr, "TIMING %ld + %ld\n", now, now - j->display_time );
+	}
+
+	j->reset();
+	if ( j->prediction_time > prediction_checkpoint ) {
+	  score++;
+	}
+	break;
+      case Pending:
+	max_delay = max( max_delay, now - j->prediction_time );
+	break;
+      default:
+	break;
+      }
+    }
+
+    i = inext;
+  }
+
+  if ( max_delay > 100 ) {
+    flagging = true;
+  } else if ( max_delay < 50 ) {
+    flagging = false;
+  }
+}
+
+ConditionalOverlayRow & PredictionEngine::get_or_make_row( int row_num, int num_cols )
+{
+  auto it = find_if( overlays.begin(), overlays.end(),
+		     [&]( const ConditionalOverlayRow &x ) { return x.row_num == row_num; } );
+
+  if ( it != overlays.end() ) {
+    return *it;
+  } else {
+    /* make row */
+    ConditionalOverlayRow r( row_num );
+    r.overlay_cells.reserve( num_cols );
+    for ( int i = 0; i < num_cols; i++ ) {
+      r.overlay_cells.push_back( ConditionalOverlayCell( i ) );
+      assert( r.overlay_cells[ i ].col == i );
+    }
+    overlays.push_back( r );
+    return overlays.back();
   }
 }
 
 void PredictionEngine::new_user_byte( char the_byte, const Framebuffer &fb )
 {
+  list<Parser::Action *> actions( parser.input( the_byte ) );
+
   uint64_t now = timestamp();
 
-  if ( elements.empty() ) {
+  for ( auto it = actions.begin(); it != actions.end(); it++ ) {
-    /* starting from scratch */
+    Parser::Action *act = *it;
 
-    elements.push_front( new ConditionalCursorMove( now + prediction_len(),
+    if ( typeid( *act ) == typeid( Parser::Print ) ) {
-						    fb.ds.get_cursor_row(),
+      /* make new prediction */
-						    fb.ds.get_cursor_col() ) );
-  }
 
-  assert( typeid( ConditionalCursorMove ) == typeid( *elements.front() ) );
+      wchar_t ch = act->ch;
-  ConditionalCursorMove *ccm = static_cast<ConditionalCursorMove *>( elements.front() );
+      /* XXX handle wide characters */
 
-  if ( (ccm->new_row >= fb.ds.get_height()) || (ccm->new_col >= fb.ds.get_width()) ) {
+      if ( !cursor.active ) {
-    return;
+	/* initialize new cursor prediction */
-  }
+	cursor.row = fb.ds.get_cursor_row();
+	cursor.col = fb.ds.get_cursor_col();
+	cursor.active = true;
+	cursor.prediction_time = now;
+	cursor.expiration_frame = local_frame_sent + 1;
+      }
       
-  if ( (the_byte >= 0x20) && (the_byte <= 0x7E) && (ccm->new_col < fb.ds.get_width() - 2) ) {
+      if ( ch == 0x7f ) { /* backspace */
-    /* XXX need to kill existing prediction if present */
+	//	fprintf( stderr, "Backspace.\n" );
+	if ( cursor.col > 0 ) {
+	  cursor.col--;
 
-    const Cell *existing_cell = fb.get_cell( ccm->new_row, ccm->new_col );
+	  cursor.prediction_time = now;
+	  cursor.expiration_frame = local_frame_sent + 1;
 
-    if ( (existing_cell->contents.size() == 1)
+	  ConditionalOverlayCell &cell = get_or_make_row( cursor.row, fb.ds.get_width() ).overlay_cells[ cursor.col ];
-	 && (existing_cell->contents.front() == the_byte) ) {
+	  cell.active = true;
-      /* do nothing */
+	  cell.tentative = (score <= 0);
-    } else if ( (existing_cell->contents.empty() || ((existing_cell->contents.size() == 1)
+	  cell.prediction_time = now;
-						     && ( (existing_cell->contents.front() == 0x20)
+	  cell.expiration_frame = local_frame_sent + 1;
-							  || (existing_cell->contents.front() == 0xA0) )))
+	  cell.replacement.renditions = fb.ds.get_renditions();
-		&& ( the_byte == 0x20 ) ) {
+	  cell.replacement.contents.clear();
-      /* don't attempt to change existing blank or space cells if user has typed space */
+	  cell.replacement.contents.push_back( 0x20 );
-    } else {
+	  cell.display_time = -1;
-      Renditions current_renditions = fb.ds.get_renditions();
+	}
+      } else if ( (ch < 0x20) || (ch > 0x7E) ) {
+	/* unknown print */
+	become_tentative();
+      } else {
+	/* don't attempt to change existing blank or space cells if user has typed space */
+	const Cell *existing_cell = fb.get_cell( cursor.row, cursor.col );
+	if ( ( existing_cell->contents.empty() || ((existing_cell->contents.size() == 1)
+						   && ( (existing_cell->contents.front() == 0x20)
+							|| (existing_cell->contents.front() == 0xA0) )))
+	     && ( ch == 0x20 ) ) {
+	  /* do nothing */
+	} else {
+	  assert( cursor.row >= 0 );
+	  assert( cursor.col >= 0 );
+	  assert( cursor.row < fb.ds.get_height() );
+	  assert( cursor.col < fb.ds.get_width() );
 
-      ConditionalOverlayCell *coc = new ConditionalOverlayCell( now + prediction_len(),
+	  if ( cursor.col + 1 >= fb.ds.get_width() ) {
-								ccm->new_row, ccm->new_col,
+	    /* prediction in the last column is tricky */
-								current_renditions.background_color,
+	    /* e.g., emacs will show wrap character, shell will just put the character there */
-								*existing_cell );
+	    become_tentative();
+	    cursor.freeze();
+	  }
 
-      coc->replacement = *existing_cell;
+	  ConditionalOverlayCell &cell = get_or_make_row( cursor.row, fb.ds.get_width() ).overlay_cells[ cursor.col ];
-      coc->replacement.renditions = current_renditions;
+	  cell.active = true;
-      coc->replacement.contents.clear();
+	  cell.tentative = (score <= 0);
-      coc->replacement.contents.push_back( the_byte );
+	  cell.prediction_time = now;
-      coc->flag = flagging;
+	  cell.expiration_frame = local_frame_sent + 1;
+	  cell.replacement.renditions = fb.ds.get_renditions();
+	  cell.replacement.contents.clear();
+	  cell.replacement.contents.push_back( ch );
+	  cell.display_time = -1;
 
-      elements.push_back( coc );
+	  /*
+	  fprintf( stderr, "[%d=>%d] Predicting %lc in row %d, col %d\n",
+		   (int)local_frame_acked, (int)cell.expiration_frame,
+		   ch, cursor.row, cursor.col );
+	  */
+	}
+
+	cursor.prediction_time = now;
+	cursor.expiration_frame = local_frame_sent + 1;
+	cursor.col++;
+
+	/* do we need to wrap? */
+	if ( cursor.col >= fb.ds.get_width() ) {
+	  become_tentative();
+	  cursor.col--;
+	  cursor.freeze();
+	  cursor.col = 0;
+	  if ( cursor.row == fb.ds.get_height() - 1 ) {
+	    for ( auto i = overlays.begin(); i != overlays.end(); i++ ) {
+	      i->row_num--;
+	      for ( auto j = i->overlay_cells.begin(); j != i->overlay_cells.end(); j++ ) {
+		if ( j->active ) {
+		  //		  j->tentative = (score <= 0);
+		  j->prediction_time = now;
+		  j->expiration_frame = local_frame_sent + 1;
+		}
+	      }
+	    }
+	  } else {
+	    cursor.row++;
+	  }
+	}
+      }
+    } else if ( typeid( *act ) == typeid( Parser::Execute ) ) {
+      become_tentative();
+      cursor.freeze();
     }
 
-    ccm->new_col++;
+    delete act;
-    ccm->expiration_time = now + prediction_len();
-  } else {
-    clear();
-    score = 0;
   }
 }
 
-int OverlayManager::wait_time( void )
+void PredictionEngine::become_tentative( void )
 {
-  uint64_t now = timestamp();
+  prediction_checkpoint = timestamp();
-
+  score = 0;
-  uint64_t next_expiry = uint64_t( -1 );
-
-  for ( auto i = notifications.begin(); i != notifications.end(); i++ ) {
-    if ( (*i)->expiration_time < next_expiry ) {
-      next_expiry = (*i)->expiration_time;
-    }
-  }
-
-  for ( auto i = predictions.begin(); i != predictions.end(); i++ ) {
-    if ( (*i)->expiration_time < next_expiry ) {
-      next_expiry = (*i)->expiration_time;
-    }
-  }
-
-  int ret = next_expiry - now;
-  if ( ret < 0 ) {
-    return INT_MAX;
-  } else {
-    return ret;
-  }
-}
-
-int PredictionEngine::prediction_len( void )
-{
-  uint64_t RTO = lrint( ceil( 1.5 * SRTT + 8 * RTTVAR ) );
-  if ( RTO < 20 ) {
-    RTO = 20;
-  } else if ( RTO > 4000 ) {
-    RTO = 4000;
-  }
-  return RTO;
 }

terminaloverlay.hpp

@@ -3,8 +3,9 @@
 
 #include "terminalframebuffer.hpp"
 #include "network.hpp"
+#include "parser.hpp"
 
-#include <list>
+#include <vector>
 
 namespace Overlay {
   using namespace Terminal;
@@ -14,118 +15,142 @@ namespace Overlay {
   enum Validity {
     Pending,
     Correct,
-    IncorrectOrExpired
+    IncorrectOrExpired,
+    Inactive
   };
 
-  /* The individual elements of an overlay -- cursor movements and replaced cells */
+  class ConditionalOverlay {
-  class OverlayElement {
   public:
-    uint64_t prediction_time, expiration_time;
+    uint64_t prediction_time, expiration_frame;
-    bool flag; /* whether to bold for the user */
+    int col;
+    bool active; /* represents a prediction at all */
+    bool tentative; /* whether to hide when score < 0 */
 
-    virtual void apply( Framebuffer &fb ) const = 0;
+    ConditionalOverlay( uint64_t s_exp, int s_col )
-    virtual Validity get_validity( const Framebuffer & ) const;
+      : prediction_time( timestamp() ),
+	expiration_frame( s_exp ), col( s_col ),
+	active( false ),
+	tentative( false )
+    {}
 
-    OverlayElement( uint64_t s_expiration_time ) : prediction_time( timestamp() ),
+    virtual ~ConditionalOverlay() {}
-						   expiration_time( s_expiration_time ),
-						   flag( false ) {}
-    virtual ~OverlayElement() {}
   };
 
-  class OverlayCell : public OverlayElement {
+  class ConditionalCursorMove : public ConditionalOverlay {
+  public:
+    int row;
+
+    int frozen_col, frozen_row; /* after a control character */
+
+    bool show_frozen_cursor;
+
+    void apply( Framebuffer &fb ) const;
+
+    Validity get_validity( const Framebuffer &fb, uint64_t current_frame ) const;
+
+    ConditionalCursorMove( uint64_t s_exp, int s_row, int s_col )
+      : ConditionalOverlay( s_exp, s_col ), row( s_row ), frozen_col( -1 ), frozen_row( -1 ),
+	show_frozen_cursor( false )
+    {}
+
+    void freeze( void ) { if ( show_frozen_cursor ) { return; } frozen_col = col; frozen_row = row; show_frozen_cursor = true; }
+    void thaw( void ) { show_frozen_cursor = false; }
+    void reset( void ) { active = false; thaw(); }
+  };
+
+  class ConditionalOverlayCell : public ConditionalOverlay {
   public:
-    int row, col;
     Cell replacement;
 
-    OverlayCell( uint64_t expiration_time, int s_row, int s_col, int background_color );
+    mutable uint64_t display_time;
-    void apply( Framebuffer &fb ) const;
-  };
 
-  class ConditionalOverlayCell : public OverlayCell {
+    void apply( Framebuffer &fb, bool show_tentative, int row, bool flag ) const;
-  public:
+    Validity get_validity( const Framebuffer &fb, int row, uint64_t current_frame ) const;
-    Cell original_contents;
 
-    Validity get_validity( const Framebuffer &fb ) const;
+    ConditionalOverlayCell( int s_col )
-
+      : ConditionalOverlay( 0, s_col ),
-    ConditionalOverlayCell( uint64_t expiration_time, int s_row, int s_col, int background_color,
+	replacement( 0 ),
-			    Cell s_original_contents )
+	display_time( -1 )
-      : OverlayCell( expiration_time, s_row, s_col, background_color ),
-	original_contents( s_original_contents )
     {}
+
+    void reset( void ) { active = false; display_time = -1; }
   };
 
-  class CursorMove : public OverlayElement {
+  class ConditionalOverlayRow {
   public:
-    int new_row, new_col;
+    int row_num;
+    vector<ConditionalOverlayCell> overlay_cells;
 
-    void apply( Framebuffer &fb ) const;
+    void apply( Framebuffer &fb, bool show_tentative, bool flag ) const;
 
-    CursorMove( uint64_t expiration_time, int s_new_row, int s_new_col );
+    ConditionalOverlayRow( int s_row_num ) : row_num( s_row_num ), overlay_cells() {}
   };
 
-  class ConditionalCursorMove : public CursorMove {
+  /* the various overlays */
-  public:
+  class NotificationEngine {
-    Validity get_validity( const Framebuffer &fb ) const;
-
-    ConditionalCursorMove( uint64_t expiration_time, int s_new_row, int s_new_col )
-      : CursorMove( expiration_time, s_new_row, s_new_col )
-    {}
-  };
-
-  /* the various overlays -- some predictive and some for local notifications */
-  class OverlayEngine {
-  protected:
-    list<OverlayElement *> elements;
-
-  public:
-    virtual void apply( Framebuffer &fb ) const;
-    void clear( void );
-
-    typename list<OverlayElement *>::const_iterator begin( void ) { return elements.begin(); }
-    typename list<OverlayElement *>::const_iterator end( void ) { return elements.end(); }
-
-    OverlayEngine() : elements() {}
-    virtual ~OverlayEngine();
-  };
-
-  class NotificationEngine : public OverlayEngine {
   private:
-    bool needs_render;
+    uint64_t last_word_from_server;
-
-    uint64_t last_word;
-    uint64_t last_render;
-
     wstring message;
     uint64_t message_expiration;
 
   public:
+    bool need_countup( uint64_t ts ) const { return ts - last_word_from_server > 4500; }
+    void adjust_message( void );
     void apply( Framebuffer &fb ) const;
-    void set_notification_string( const wstring s_message );
+    void set_notification_string( const wstring s_message ) { message = s_message; message_expiration = timestamp() + 1000; }
-    const wstring &get_notification_string( void ) { return message; }
+    const wstring &get_notification_string( void ) const { return message; }
-    void server_ping( uint64_t s_last_word );
+    void server_heard( uint64_t s_last_word ) { last_word_from_server = s_last_word; }
-    void render_notification( void );
+    uint64_t get_message_expiration( void ) const { return message_expiration; }
 
     NotificationEngine();
   };
 
-  class PredictionEngine : public OverlayEngine {
+  class PredictionEngine {
   private:
+    Parser::UTF8Parser parser;
+
+    list<ConditionalOverlayRow> overlays;
+
+    ConditionalCursorMove cursor;
+
     int score;
 
-    /* use the TCP timeout algorithm to measure appropriate echo prediction timeout */
+    uint64_t local_frame_sent, local_frame_acked;
-    bool RTT_hit;
+
-    double SRTT, RTTVAR;
+    ConditionalOverlayRow & get_or_make_row( int row_num, int num_cols );
+
+    uint64_t prediction_checkpoint;
+
+    void become_tentative( void );
+
     bool flagging;
-    int prediction_len( void );
 
   public:
-    void cull( const Framebuffer &fb );
+    void apply( Framebuffer &fb ) const;
     void new_user_byte( char the_byte, const Framebuffer &fb );
-    void calculate_score( const Framebuffer &fb );
+    void cull( const Framebuffer &fb );
 
-    PredictionEngine() : score( 0 ), RTT_hit( false ), SRTT( 1000 ), RTTVAR( 500 ), flagging( false ) {}
+    void reset( void );
 
-    int get_score( void ) { return score; }
+    void set_local_frame_sent( uint64_t x ) { local_frame_sent = x; }
+    void set_local_frame_acked( uint64_t x ) { local_frame_acked = x; }
+
+    PredictionEngine( void ) : parser(), overlays(), cursor( 0, 0, 0 ), score( 0 ),
+			       local_frame_sent( 0 ), local_frame_acked( 0 ),
+			       prediction_checkpoint( timestamp() ), flagging( false )
+    {
+      become_tentative();
+    }
+  };
+
+  class TitleEngine {
+  private:
+    deque<wchar_t> prefix;
+
+  public:
+    void apply( Framebuffer &fb ) const { fb.prefix_window_title( prefix ); }
+    void set_prefix( const wstring s );
+    TitleEngine() : prefix() {}
   };
 
   /* the overlay manager */
@@ -133,6 +158,7 @@ namespace Overlay {
   private:
     NotificationEngine notifications;
     PredictionEngine predictions;
+    TitleEngine title;
 
   public:
     void apply( Framebuffer &fb );
@@ -140,7 +166,9 @@ namespace Overlay {
     NotificationEngine & get_notification_engine( void ) { return notifications; }
     PredictionEngine & get_prediction_engine( void ) { return predictions; }
 
-    OverlayManager() : notifications(), predictions() {}
+    void set_title_prefix( const wstring s ) { title.set_prefix( s ); }
+
+    OverlayManager() : notifications(), predictions(), title() {}
 
     int wait_time( void );
   };

transportsender.hpp

@@ -94,6 +94,9 @@ namespace Network {
     bool get_shutdown_in_progress( void ) { return shutdown_in_progress; }
     bool get_shutdown_acknowledged( void ) { return sent_states.front().num == uint64_t(-1); }
     bool get_counterparty_shutdown_acknowledged( void ) { return fragmenter.last_ack_sent() == uint64_t(-1); }
+    uint64_t get_sent_state_acked( void ) { return sent_states.front().num; }
+    uint64_t get_sent_state_last( void ) { return sent_states.back().num; }
+
     bool shutdown_ack_timed_out( void );
 
     void set_send_delay( int new_delay ) { SEND_MINDELAY = new_delay; }