Optional verifier for round-trippability, and fix wrapping and tab bugs.

src/network/transportsender.cc

@@ -143,6 +143,15 @@ void TransportSender<MyState>::tick( void )
     
   string diff = current_state.diff_from( assumed_receiver_state->state );
 
+  /* verify diff has round-trip identity (modulo Unicode fallback rendering) */
+  /*
+  MyState newstate( assumed_receiver_state->state );
+  newstate.apply_string( diff );
+  if ( current_state.compare( newstate ) ) {
+    fprintf( stderr, "Diff: %s\n", diff.c_str() );
+  }
+  */
+
   if ( diff.empty() && (now >= next_ack_time) ) {
     send_empty_ack();
     return;

src/statesync/completeterminal.cc

@@ -153,3 +153,26 @@ int Complete::wait_time( uint64_t now ) const
     return next_echo_ack_time - now;
   }
 }
+
+bool Complete::compare( const Complete &other ) const
+{
+  bool ret = false;
+  for ( int x = 0; x < terminal.get_fb().ds.get_width(); x++ ) {
+    for ( int y = 0; y < terminal.get_fb().ds.get_height(); y++ ) {
+      if ( terminal.get_fb().get_cell( y, x )->compare( *other.terminal.get_fb().get_cell( y, x ) ) ) {
+	fprintf( stderr, "Cell (%d, %d) differs.\n", y, x );
+	ret = true;
+      }
+    }
+  }
+
+  if ( (terminal.get_fb().ds.get_cursor_row() != other.terminal.get_fb().ds.get_cursor_row())
+       || (terminal.get_fb().ds.get_cursor_col() != other.terminal.get_fb().ds.get_cursor_col()) ) {
+    fprintf( stderr, "Cursor mismatch: (%d, %d) vs. (%d, %d).\n",
+	     terminal.get_fb().ds.get_cursor_row(), terminal.get_fb().ds.get_cursor_col(),
+	     other.terminal.get_fb().ds.get_cursor_row(), other.terminal.get_fb().ds.get_cursor_col() );
+    ret = true;
+  }
+
+  return ret;
+}

src/statesync/completeterminal.h

@@ -60,6 +60,8 @@ namespace Terminal {
     std::string diff_from( const Complete &existing ) const;
     void apply_string( std::string diff );
     bool operator==( const Complete &x ) const;
+
+    bool compare( const Complete &other ) const;
   };
 }
 

src/statesync/user.h

@@ -77,6 +77,8 @@ namespace Network {
     string diff_from( const UserStream &existing ) const;
     void apply_string( string diff );
     bool operator==( const UserStream &x ) const { return actions == x.actions; }
+
+    bool compare( const UserStream & ) const { return false; }
   };
 }
 

src/terminal/terminaldisplay.cc

@@ -193,21 +193,23 @@ std::string Display::new_frame( bool initialized, const Framebuffer &last, const
 	  frame.x < f.ds.get_width(); /* let put_cell() handle advance */ ) {
       last_x = frame.x;
       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 ( (frame.cursor_x >= f.ds.get_width())
-	   && (frame.y < f.ds.get_height() - 1)
-	   && f.get_row( frame.y )->get_wrap()
-	   && (!initialized || !frame.last_frame.get_row( frame.y )->get_wrap()) ) {
+    if ( (frame.y < f.ds.get_height() - 1)
+	 && f.get_row( frame.y )->get_wrap() ) {
+      frame.x = last_x;
+      frame.force_next_put = true;
+      put_cell( initialized, frame, f );
+
       /* next write will wrap */
       frame.cursor_x = 0;
       frame.cursor_y++;
       frame.force_next_put = true;
     }
-    }
 
     /* Turn off wrap */
     if ( (frame.y < f.ds.get_height() - 1)
@@ -301,8 +303,10 @@ void Display::put_cell( bool initialized, FrameState &frame, const Framebuffer &
 
     if ( frame.force_next_put ) {
       frame.append( " " );
-      frame.append_silent_move( frame.y, frame.x );
+      frame.cursor_x++;
+      frame.x++;
       frame.force_next_put = false;
+      return;
     }
 
     /* can we go to the end of the line? */

src/terminal/terminalframebuffer.cc

@@ -366,7 +366,7 @@ void DrawState::resize( int s_width, int s_height )
 
   snap_cursor_to_border();
 
-  tabs.resize( width );
+  tabs.clear();
 
   /* saved cursor will be snapped to border on restore */
 
@@ -482,11 +482,6 @@ std::string Renditions::sgr( void ) const
 
 /* 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
@@ -573,3 +568,40 @@ wchar_t Cell::debug_contents( void ) const
     return contents.front();
   }
 }
+
+bool Cell::compare( const Cell &other ) const
+{
+  bool ret = false;
+
+  if ( !contents_match( other ) ) {
+    ret = true;
+    fprintf( stderr, "Contents: %lc vs. %lc\n",
+	     debug_contents(), other.debug_contents() );
+  }
+
+  if ( fallback != other.fallback ) {
+    ret = true;
+    fprintf( stderr, "fallback: %d vs. %d\n",
+	     fallback, other.fallback );
+  }
+
+  if ( width != other.width ) {
+    ret = true;
+    fprintf( stderr, "width: %d vs. %d\n",
+	     width, other.width );
+  }
+
+  if ( !(renditions == other.renditions) ) {
+    ret = true;
+    fprintf( stderr, "renditions: %s vs. %s\n",
+	     renditions.sgr().c_str(), other.renditions.sgr().c_str() );
+  }
+
+  if ( wrap != other.wrap ) {
+    ret = true;
+    fprintf( stderr, "wrap: %d vs. %d\n",
+	     wrap, other.wrap );
+  }
+
+  return ret;
+}

src/terminal/terminalframebuffer.h

@@ -102,6 +102,8 @@ namespace Terminal {
       return ( is_blank() && other.is_blank() )
              || ( contents == other.contents );
     }
+
+    bool compare( const Cell &other ) const;
   };
 
   class Row {