Improve roundtrip verification tests and debug dump.

Add another round-trip verification.  For both original and generated
state, generate a diff from an initial, empty state.  Verify that
these two diffs are the same.

src/network/transportsender.cc

@@ -176,6 +176,12 @@ void TransportSender<MyState>::tick( void )
     if ( current_state.compare( newstate ) ) {
       fprintf( stderr, "Warning, round-trip Instruction verification failed!\n" );
     }
+    /* Also verify that both the original frame and generated frame have the same initial diff. */
+    std::string current_diff( current_state.init_diff() );
+    std::string new_diff( newstate.init_diff() );
+    if ( current_diff != new_diff ) {
+      fprintf( stderr, "Warning, target state Instruction verification failed!\n" );
+    }
   }
 
   if ( diff.empty() && (now >= next_ack_time) ) {

src/statesync/completeterminal.cc

@@ -94,6 +94,11 @@ string Complete::diff_from( const Complete &existing ) const
   return output.SerializeAsString();
 }
 
+string Complete::init_diff( void ) const
+{
+  return diff_from( Complete( get_fb().ds.get_width(), get_fb().ds.get_height() ));
+}
+
 void Complete::apply_string( string diff )
 {
   HostBuffers::HostMessage input;
@@ -174,22 +179,35 @@ int Complete::wait_time( uint64_t now ) const
 bool Complete::compare( const Complete &other ) const
 {
   bool ret = false;
-  for ( int y = 0; y < terminal.get_fb().ds.get_height(); y++ ) {
-    for ( int x = 0; x < terminal.get_fb().ds.get_width(); x++ ) {
-      if ( terminal.get_fb().get_cell( y, x )->compare( *other.terminal.get_fb().get_cell( y, x ) ) ) {
+  const Framebuffer &fb = terminal.get_fb();
+  const Framebuffer &other_fb = other.terminal.get_fb();
+  const int height = fb.ds.get_height();
+  const int other_height = other_fb.ds.get_height();
+  const int width = fb.ds.get_width();
+  const int other_width = other_fb.ds.get_width();
+
+  if ( height != other_height || width != other_width ) {
+    fprintf( stderr, "Framebuffer size (%dx%d, %dx%d) differs.\n", width, height, other_width, other_height );
+    return true;
+  }
+
+  for ( int y = 0; y < height; y++ ) {
+    for ( int x = 0; x < width; x++ ) {
+      if ( fb.get_cell( y, x )->compare( *other_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()) ) {
+  if ( (fb.ds.get_cursor_row() != other_fb.ds.get_cursor_row())
+       || (fb.ds.get_cursor_col() != other_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() );
+	     fb.ds.get_cursor_row(), fb.ds.get_cursor_col(),
+	     other_fb.ds.get_cursor_row(), other_fb.ds.get_cursor_col() );
     ret = true;
   }
+  /* XXX should compare other terminal state too (mouse mode, bell. etc.) */
 
   return ret;
 }

src/statesync/completeterminal.h

@@ -76,6 +76,7 @@ namespace Terminal {
     /* interface for Network::Transport */
     void subtract( const Complete * ) const {}
     std::string diff_from( const Complete &existing ) const;
+    std::string init_diff( void ) const;
     void apply_string( std::string diff );
     bool operator==( const Complete &x ) const;
 

src/statesync/user.h

@@ -89,6 +89,7 @@ namespace Network {
     /* interface for Network::Transport */
     void subtract( const UserStream *prefix );
     string diff_from( const UserStream &existing ) const;
+    string init_diff( void ) const { assert( false ); return string(); };
     void apply_string( string diff );
     bool operator==( const UserStream &x ) const { return actions == x.actions; }
 

src/terminal/terminalframebuffer.cc

@@ -643,16 +643,26 @@ void Framebuffer::prefix_window_title( const title_type &s )
   window_title.insert(window_title.begin(), s.begin(), s.end() );
 }
 
-wint_t Cell::debug_contents( void ) const
+std::string Cell::debug_contents( void ) const
 {
   if ( contents.empty() ) {
-    return '_';
+    return "'_' ()";
   } else {
-    /* very, very cheesy */
-    wchar_t ch[2];
-    const std::string chars( contents.begin(), contents.end() );
-    mbstowcs(ch, chars.c_str(), 1);
-    return ch[0];
+    std::string chars( 1, '\'' );
+    print_grapheme( chars );
+    chars.append( "' [" );
+    const char *lazycomma = "";
+    char buf[64];
+    for ( content_type::const_iterator i = contents.begin();
+	  i < contents.end();
+	  i++ ) {
+
+      sprintf( buf, "%s0x%02x", lazycomma, static_cast<uint8_t>(*i) );
+      chars.append( buf );
+      lazycomma = ", ";
+    }
+    chars.append( "]" );
+    return chars;
   }
 }
 
@@ -660,15 +670,28 @@ bool Cell::compare( const Cell &other ) const
 {
   bool ret = false;
 
-  if ( !contents_match( other ) ) {
+  std::string grapheme, other_grapheme;
+
+  print_grapheme( grapheme );
+  other.print_grapheme( other_grapheme );
+
+  if ( grapheme != other_grapheme ) {
     ret = true;
-    fprintf( stderr, "Contents: %lc (%ld) vs. %lc (%ld)\n",
-	     debug_contents(), contents.size(),
-	     other.debug_contents(), other.contents.size() );
+  fprintf( stderr, "Graphemes: '%s' vs. '%s'\n",
+	   grapheme.c_str(), other_grapheme.c_str() );
+  }
+
+  if ( !contents_match( other ) ) {
+    // ret = true;
+    fprintf( stderr, "Contents: %s (%ld) vs. %s (%ld)\n",
+	     debug_contents().c_str(),
+	     static_cast<long int>( contents.size() ),
+	     other.debug_contents().c_str(),
+	     static_cast<long int>( other.contents.size() ) );
   }
 
   if ( fallback != other.fallback ) {
-    ret = true;
+    // ret = true;
     fprintf( stderr, "fallback: %d vs. %d\n",
 	     fallback, other.fallback );
   }

src/terminal/terminalframebuffer.h

@@ -109,7 +109,7 @@ namespace Terminal {
 
     bool operator!=( const Cell &x ) const { return !operator==( x ); }
 
-    wint_t debug_contents( void ) const;
+    std::string debug_contents( void ) const;
 
     bool is_blank( void ) const
     {
@@ -165,18 +165,18 @@ namespace Terminal {
 
     void print_grapheme( std::string &output ) const
     {
-      if ( cell.contents.empty() ) {
-	output.append( ' ' );
+      if ( contents.empty() ) {
+	output.append( 1, ' ' );
 	return;
       }
       /*
        * cells that begin with combining character get combiner
        * attached to no-break space
        */
-      if ( cell.fallback ) {
+      if ( fallback ) {
 	output.append( "\xC2\xA0" );
       }
-      output.append( cell.contents );
+      output.append( contents );
     }
   };