[PATCH] Remove fields curch and cur_line from TUI_CMD_WIN

[Patrick Palka <patrick at parcs dot ath dot cx>]

These fields are currently used to track the location of the cursor
inside the command window.  But their usefulness is questionable because
ncurses already internally keeps track of the location of the cursor,
whose coordinates we can query using the functions getyx(), getcurx() or
getcury().  It is an unnecessary pain to keep these fields in sync with
ncurses, and their meaning is not well-defined anyway.  For instance, it
is not clear whether the coordinates held in these fields are
authoritative, or whether the coordinates reported by ncurses are.

So to keep things simple, this patch removes these fields and replaces
existing reads of these fields with calls to the appropriate ncurses
querying functions, and writes to these fields with calls to wmove()
(when necessary and applicable).

In the function tui_cont_sig(), I removed the call to wmove() entirely
because moving to (start_line, curch) makes no sense.  The move should
have been to (cur_line, curch) -- which would now be a no-op.

Does this seem like a step in the right direction?  These fields like an
unnecessary abstraction.

Tested on x86_64 Fedora 22, with seemingly no obvious regressions.

gdb/ChangeLog:

	* tui/tui-data.h (tui_command_info): Remove fields cur_line and
	curch.
	* tui/tui-data.c (tui_clear_win_detail) [CMD_WIN]: Don't set
	cur_line or curch, instead call wmove().
	(init_win_info) [CMD_WIN]: Likewise.
	* tui/tui-io.c (tui_puts): Likewise. Don't read cur_line,
	instead call getcury().
	(tui_redisplay_readline): Don't set cur_line or curch.
	(tui_mld_erase_entire_line): Don't read cur_line, instead call
	getcury().
	(tui_cont_sig): Remove call to wmove.
	(tui_getc): Don't read cur_line or curch, instead call getcury()
	or getyx().  Don't set curch.
	* tui/tui-win.c (make_visible_with_new_height) [CMD_WIN]: Don't
	set cur_line or curch.  Always move cursor to (0,0).
---
 gdb/tui/tui-data.c |  5 +----
 gdb/tui/tui-data.h |  2 --
 gdb/tui/tui-io.c   | 36 ++++++++++--------------------------
 gdb/tui/tui-win.c  |  6 +-----
 4 files changed, 12 insertions(+), 37 deletions(-)

diff --git a/gdb/tui/tui-data.c b/gdb/tui/tui-data.c
index 0c350d8..f610d9c 100644
--- a/gdb/tui/tui-data.c
+++ b/gdb/tui/tui-data.c
@@ -212,8 +212,7 @@ tui_clear_win_detail (struct tui_win_info *win_info)
 	  win_info->detail.source_info.horizontal_offset = 0;
 	  break;
 	case CMD_WIN:
-	  win_info->detail.command_info.cur_line =
-	    win_info->detail.command_info.curch = 0;
+	  wmove (win_info->generic.handle, 0, 0);
 	  break;
 	case DATA_WIN:
 	  win_info->detail.data_display_info.data_content =
@@ -546,8 +545,6 @@ init_win_info (struct tui_win_info *win_info)
       win_info->detail.data_display_info.current_group = 0;
       break;
     case CMD_WIN:
-      win_info->detail.command_info.cur_line = 0;
-      win_info->detail.command_info.curch = 0;
       break;
     default:
       win_info->detail.opaque = NULL;
diff --git a/gdb/tui/tui-data.h b/gdb/tui/tui-data.h
index 0e7e31e..df1fe6c 100644
--- a/gdb/tui/tui-data.h
+++ b/gdb/tui/tui-data.h
@@ -265,8 +265,6 @@ struct tui_source_info
 
 struct tui_command_info
 {
-  int cur_line;			/* The current line position.  */
-  int curch;			/* The current cursor position.  */
   int start_line;
 };
 
diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index 97906ce..f0ff5c0 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -187,10 +187,7 @@ tui_puts (const char *string)
       else if (c == '\n')
         tui_skip_line = -1;
     }
-  getyx (w, TUI_CMD_WIN->detail.command_info.cur_line,
-         TUI_CMD_WIN->detail.command_info.curch);
-  TUI_CMD_WIN->detail.command_info.start_line
-    = TUI_CMD_WIN->detail.command_info.cur_line;
+  TUI_CMD_WIN->detail.command_info.start_line = getcury (w);
 }
 
 /* Readline callback.
@@ -271,24 +268,16 @@ tui_redisplay_readline (void)
           waddch (w, c);
 	}
       if (c == '\n')
-        {
-          getyx (w, TUI_CMD_WIN->detail.command_info.start_line,
-                 TUI_CMD_WIN->detail.command_info.curch);
-        }
+	TUI_CMD_WIN->detail.command_info.start_line = getcury (w);
       getyx (w, line, col);
       if (col < prev_col)
         height++;
       prev_col = col;
     }
   wclrtobot (w);
-  getyx (w, TUI_CMD_WIN->detail.command_info.start_line,
-         TUI_CMD_WIN->detail.command_info.curch);
+  TUI_CMD_WIN->detail.command_info.start_line = getcury (w);
   if (c_line >= 0)
-    {
-      wmove (w, c_line, c_pos);
-      TUI_CMD_WIN->detail.command_info.cur_line = c_line;
-      TUI_CMD_WIN->detail.command_info.curch = c_pos;
-    }
+    wmove (w, c_line, c_pos);
   TUI_CMD_WIN->detail.command_info.start_line -= height - 1;
 
   wrefresh (w);
@@ -371,10 +360,11 @@ static void
 tui_mld_erase_entire_line (const struct match_list_displayer *displayer)
 {
   WINDOW *w = TUI_CMD_WIN->generic.handle;
+  int cur_y = getcury (w);
 
-  wmove (w, TUI_CMD_WIN->detail.command_info.cur_line, 0);
+  wmove (w, cur_y, 0);
   wclrtoeol (w);
-  wmove (w, TUI_CMD_WIN->detail.command_info.cur_line, 0);
+  wmove (w, cur_y, 0);
 }
 
 /* TUI version of displayer.beep.  */
@@ -521,10 +511,6 @@ tui_cont_sig (int sig)
       /* Force a refresh of the screen.  */
       tui_refresh_all_win ();
 
-      /* Update cursor position on the screen.  */
-      wmove (TUI_CMD_WIN->generic.handle,
-             TUI_CMD_WIN->detail.command_info.start_line,
-             TUI_CMD_WIN->detail.command_info.curch);
       wrefresh (TUI_CMD_WIN->generic.handle);
     }
   signal (sig, tui_cont_sig);
@@ -601,7 +587,7 @@ tui_getc (FILE *fp)
          user we recognized the command.  */
       if (rl_end == 0)
         {
-          wmove (w, TUI_CMD_WIN->detail.command_info.cur_line, 0);
+	  wmove (w, getcury (w), 0);
 
           /* Clear the line.  This will blink the gdb prompt since
              it will be redrawn at the same line.  */
@@ -614,8 +600,8 @@ tui_getc (FILE *fp)
 	  /* Move cursor to the end of the command line before emitting the
 	     newline.  We need to do so because when ncurses outputs a newline
 	     it truncates any text that appears past the end of the cursor.  */
-	  int px = TUI_CMD_WIN->detail.command_info.curch;
-	  int py = TUI_CMD_WIN->detail.command_info.cur_line;
+	  int px, py;
+	  getyx (w, py, px);
 	  px += rl_end - rl_point;
 	  py += px / TUI_CMD_WIN->generic.width;
 	  px %= TUI_CMD_WIN->generic.width;
@@ -627,8 +613,6 @@ tui_getc (FILE *fp)
   /* Handle prev/next/up/down here.  */
   ch = tui_dispatch_ctrl_char (ch);
   
-  if (ch == '\n' || ch == '\r' || ch == '\f')
-    TUI_CMD_WIN->detail.command_info.curch = 0;
   if (ch == KEY_BACKSPACE)
     return '\b';
 
diff --git a/gdb/tui/tui-win.c b/gdb/tui/tui-win.c
index 29ad279..6768d35 100644
--- a/gdb/tui/tui-win.c
+++ b/gdb/tui/tui-win.c
@@ -1525,8 +1525,6 @@ make_visible_with_new_height (struct tui_win_info *win_info)
       tui_display_all_data ();
       break;
     case CMD_WIN:
-      win_info->detail.command_info.cur_line = 0;
-      win_info->detail.command_info.curch = 0;
 #ifdef HAVE_WRESIZE
       wresize (TUI_CMD_WIN->generic.handle,
 	       TUI_CMD_WIN->generic.height,
@@ -1535,9 +1533,7 @@ make_visible_with_new_height (struct tui_win_info *win_info)
       mvwin (TUI_CMD_WIN->generic.handle,
 	     TUI_CMD_WIN->generic.origin.y,
 	     TUI_CMD_WIN->generic.origin.x);
-      wmove (win_info->generic.handle,
-	     win_info->detail.command_info.cur_line,
-	     win_info->detail.command_info.curch);
+      wmove (win_info->generic.handle, 0, 0);
       break;
     default:
       break;
-- 
2.5.0.248.g1233236.dirty