Use TERM env var / terminfo to decide whether to send ECH. Fixes tmux bug.

Closes #28 github issue.

src/terminal/Makefile.am

@@ -3,5 +3,4 @@ AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(PICKY_CXXFLAGS) -fno-default-inline -pipe
 
 noinst_LIBRARIES = libmoshterminal.a
 
-libmoshterminal_a_SOURCES = parseraction.cc parseraction.h parser.cc parser.h parserstate.cc parserstatefamily.h parserstate.h parsertransition.h terminal.cc terminaldispatcher.cc terminaldispatcher.h terminaldisplay.cc terminaldisplay.h terminalframebuffer.cc terminalframebuffer.h terminalfunctions.cc terminal.h terminaluserinput.cc terminaluserinput.h
-
+libmoshterminal_a_SOURCES = parseraction.cc parseraction.h parser.cc parser.h parserstate.cc parserstatefamily.h parserstate.h parsertransition.h terminal.cc terminaldispatcher.cc terminaldispatcher.h terminaldisplay.cc terminaldisplayinit.cc terminaldisplay.h terminalframebuffer.cc terminalframebuffer.h terminalfunctions.cc terminal.h terminaluserinput.cc terminaluserinput.h

src/terminal/terminaldisplay.cc

@@ -25,7 +25,7 @@ using namespace Terminal;
 
 /* Print a new "frame" to the terminal, using ANSI/ECMA-48 escape codes. */
 
-std::string Display::new_frame( bool initialized, const Framebuffer &last, const Framebuffer &f )
+std::string Display::new_frame( bool initialized, const Framebuffer &last, const Framebuffer &f ) const
 {
   FrameState frame( last );
 
@@ -201,7 +201,7 @@ std::string Display::new_frame( bool initialized, const Framebuffer &last, const
   return frame.str;
 }
 
-void Display::put_cell( bool initialized, FrameState &frame, const Framebuffer &f )
+void Display::put_cell( bool initialized, FrameState &frame, const Framebuffer &f ) const
 {
   char tmp[ 64 ];
 
@@ -238,13 +238,28 @@ void Display::put_cell( bool initialized, FrameState &frame, const Framebuffer &
       }
     }
 
-    frame.x += clear_count;
-    if ( frame.x >= f.ds.get_width() ) {
+    assert( frame.x + clear_count <= f.ds.get_width() );
+
+    /* can we go to the end of the line? */
+    if ( frame.x + clear_count == f.ds.get_width() ) {
       snprintf( tmp, 64, "\033[K" );
+      frame.append( tmp );
+      frame.x += clear_count;
     } else {
-      snprintf( tmp, 64, "\033[%dX", clear_count );
+      if ( has_ech ) {
+	if ( clear_count == 1 ) {
+	  frame.append( "\033[X" );
+	} else {
+	  snprintf( tmp, 64, "\033[%dX", clear_count );
+	  frame.append( tmp );
+	}
+	frame.x += clear_count;
+      } else { /* no ECH, so just print a space */
+	frame.append( " " );
+	frame.cursor_x++;
+	frame.x++;
+      }
     }
-    frame.append( tmp );
 
     return;
   }

src/terminal/terminaldisplay.h

@@ -49,10 +49,15 @@ namespace Terminal {
 
   class Display {
   private:
-    static void put_cell( bool initialized, FrameState &frame, const Framebuffer &f );
+    bool has_ech; /* erase character is part of vt200 but not supported by tmux
+		     (or by "screen" terminfo entry, which is what tmux advertises) */
+
+    void put_cell( bool initialized, FrameState &frame, const Framebuffer &f ) const;
 
   public:
-    static std::string new_frame( bool initialized, const Framebuffer &last, const Framebuffer &f );
+    std::string new_frame( bool initialized, const Framebuffer &last, const Framebuffer &f ) const;
+
+    Display( bool use_environment );
   };
 }
 

src/terminal/terminaldisplayinit.cc

@@ -0,0 +1,60 @@
+/*
+    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/>.
+*/
+
+/* This is in its own file because otherwise the ncurses #defines
+   alias our own variable names. */
+
+#include "terminaldisplay.h"
+
+#include <string>
+
+#include <curses.h>
+#include <term.h>
+
+using namespace Terminal;
+
+Display::Display( bool use_environment )
+  : has_ech( true )
+{
+  if ( use_environment ) {
+    int errret = -2;
+    int ret = setupterm( (char *)0, 1, &errret );
+
+    if ( ret != OK ) {
+      switch ( errret ) {
+      case 1:
+	throw std::string( "Terminal is hardcopy and cannot be used by curses applications." );
+	break;
+      case 0:
+	throw std::string( "Unknown terminal type." );
+	break;
+      case -1:
+	throw std::string( "Terminfo database could not be found." );
+	break;
+      default:
+	throw std::string( "Unknown terminfo error." );
+	break;
+      } 
+    }
+
+    char *val = tigetstr( "ech" );
+    if ( val <= 0 ) {
+      has_ech = false;
+    }
+  }
+}