From 99f55b7bbc4d375d3b4525e449001dad6e536cdd Mon Sep 17 00:00:00 2001
From: Boris Faure <billiob@gmail.com>
Date: Tue, 20 Dec 2016 22:43:37 +0100
Subject: [PATCH] termptyesc: support DECSED3 to erase the backlog. Closes
 T3713

---
 src/bin/termptyesc.c | 60 +++++++++++++++++++++++++++++++-------------
 src/bin/termptyops.c | 43 +++++++++++++++++--------------
 src/bin/termptyops.h |  1 +
 3 files changed, 68 insertions(+), 36 deletions(-)

diff --git a/src/bin/termptyesc.c b/src/bin/termptyesc.c
index 774bc79a..7cb1357d 100644
--- a/src/bin/termptyesc.c
+++ b/src/bin/termptyesc.c
@@ -980,30 +980,56 @@ _handle_esc_csi(Termpty *ty, const Eina_Unicode *c, Eina_Unicode *ce)
              termpty_write(ty, bf, strlen(bf));
           }
         break;
-      case 'J': // "2j" erases the screen, 1j erase from screen start to curs, 0j erase cursor to end of screen
-        DBG("2j erases the screen, 1j erase from screen start to curs, 0j erase cursor to end of screen");
-        arg = _csi_arg_get(&b);
-        if (b)
+      case 'J':
+        if (*b == '?')
           {
-             if ((arg >= TERMPTY_CLR_END) && (arg <= TERMPTY_CLR_ALL))
-               termpty_clear_screen(ty, arg);
-             else
-               WRN("invalid clr scr %i", arg);
+             b++;
+             arg = _csi_arg_get(&b);
+             WRN("Unsupported selected erase in display %d", arg);
           }
         else
-          termpty_clear_screen(ty, TERMPTY_CLR_END);
+          arg = _csi_arg_get(&b);
+        if (arg < 1) arg = 0;
+        /* 3J erases the backlog,
+         * 2J erases the screen,
+         * 1J erase from screen start to cursor,
+         * 0J erase form cursor to end of screen
+         */
+        DBG("ED/DECSED %d: erase in display", arg);
+        switch (arg)
+          {
+           case TERMPTY_CLR_END:
+           case TERMPTY_CLR_BEGIN:
+           case TERMPTY_CLR_ALL:
+              termpty_clear_screen(ty, arg);
+              break;
+           case 3:
+              termpty_clear_backlog(ty);
+              break;
+           default:
+              ERR("invalid EL/DECSEL argument %d", arg);
+          }
         break;
       case 'K': // 0K erase to end of line, 1K erase from screen start to cursor, 2K erase all of line
-        arg = _csi_arg_get(&b);
-        DBG("0K erase to end of line, 1K erase from screen start to cursor, 2K erase all of line: %d", arg);
-        if (b)
+        if (*b == '?')
           {
-             if ((arg >= TERMPTY_CLR_END) && (arg <= TERMPTY_CLR_ALL))
-               termpty_clear_line(ty, arg, ty->w);
-             else
-               WRN("invalid clr lin %i", arg);
+             b++;
+             arg = _csi_arg_get(&b);
+             WRN("Unsupported selected erase in line %d", arg);
+          }
+        arg = _csi_arg_get(&b);
+        if (arg < 1) arg = 0;
+        DBG("EL/DECSEL %d: erase in line", arg);
+        switch (arg)
+          {
+           case TERMPTY_CLR_END:
+           case TERMPTY_CLR_BEGIN:
+           case TERMPTY_CLR_ALL:
+              termpty_clear_line(ty, arg, ty->w);
+              break;
+           default:
+              ERR("invalid EL/DECSEL argument %d", arg);
           }
-        else termpty_clear_line(ty, TERMPTY_CLR_END, ty->w);
         break;
       case 'h':
       case 'l':
diff --git a/src/bin/termptyops.c b/src/bin/termptyops.c
index 0a69ed2d..698efbb8 100644
--- a/src/bin/termptyops.c
+++ b/src/bin/termptyops.c
@@ -275,6 +275,29 @@ termpty_clear_tabs_on_screen(Termpty *ty)
      }
 }
 
+void
+termpty_clear_backlog(Termpty *ty)
+{
+   int backsize;
+
+   ty->backlog_beacon.screen_y = 0;
+   ty->backlog_beacon.backlog_y = 0;
+
+   termpty_backlog_lock();
+   if (ty->back)
+     {
+        size_t i;
+        for (i = 0; i < ty->backsize; i++)
+          termpty_save_free(&ty->back[i]);
+        free(ty->back);
+        ty->back = NULL;
+     }
+   ty->backpos = 0;
+   backsize = ty->backsize;
+   ty->backsize = 0;
+   termpty_backlog_size_set(ty, backsize);
+   termpty_backlog_unlock();
+}
 
 void
 termpty_clear_screen(Termpty *ty, Termpty_Clear mode)
@@ -370,7 +393,6 @@ termpty_reset_att(Termatt *att)
 void
 termpty_reset_state(Termpty *ty)
 {
-   int backsize;
    int i;
 
    ty->cursor_state.cx = 0;
@@ -403,24 +425,7 @@ termpty_reset_state(Termpty *ty)
    ty->mouse_ext = MOUSE_EXT_NONE;
    ty->bracketed_paste = 0;
 
-   ty->backlog_beacon.screen_y = 0;
-   ty->backlog_beacon.backlog_y = 0;
-
-   termpty_backlog_lock();
-   if (ty->back)
-     {
-        size_t j;
-        for (j = 0; j < ty->backsize; j++)
-          termpty_save_free(&ty->back[j]);
-        free(ty->back);
-        ty->back = NULL;
-     }
-   ty->backpos = 0;
-   backsize = ty->backsize;
-   ty->backsize = 0;
-   termpty_backlog_size_set(ty, backsize);
-   termpty_backlog_unlock();
-
+   termpty_clear_backlog(ty);
    termpty_clear_tabs_on_screen(ty);
    for (i = 0; i < ty->w; i += TAB_WIDTH)
      {
diff --git a/src/bin/termptyops.h b/src/bin/termptyops.h
index deaf204b..c2be8f29 100644
--- a/src/bin/termptyops.h
+++ b/src/bin/termptyops.h
@@ -23,6 +23,7 @@ void termpty_reset_att(Termatt *att);
 void termpty_reset_state(Termpty *ty);
 void termpty_cursor_copy(Termpty *ty, Eina_Bool save);
 void termpty_clear_tabs_on_screen(Termpty *ty);
+void termpty_clear_backlog(Termpty *ty);
 
 #define _term_txt_write(ty, txt) termpty_write(ty, txt, sizeof(txt) - 1)