[PATCH] Fix truncation of TUI command history

[PATCH] Fix truncation of TUI command history

[Patrick Palka]

If we submit a command while the prompt cursor is somewhere other than
at the end of the command line, the command line gets truncated as the
command window gets shifted one line up.  This happens because we fail
to properly move the cursor to the end of the command line before
transmitting the newline to ncurses.  We need to move the cursor because
when ncurses outputs a newline it truncates any text that appears
past the end of the cursor.

	* tui/tui-io.c (tui_getc): Move cursor to the end of the command
	line before printing a newline.
---
 gdb/tui/tui-io.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index aa14790..eee5f1ac6 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -678,8 +678,9 @@ tui_getc (FILE *fp)
         }
       else
         {
+          /* Move cursor to the end of the command line.  */
           wmove (w, TUI_CMD_WIN->detail.command_info.cur_line,
-                 TUI_CMD_WIN->detail.command_info.curch);
+		 strlen (tui_rl_saved_prompt) + rl_end);
           waddch (w, ch);
         }
     }
-- 
2.1.0

Re: [PATCH] Fix truncation of TUI command history

[Pedro Alves]

Hi Patrick,

On 08/30/2014 07:11 PM, Patrick Palka wrote:
> index aa14790..eee5f1ac6 100644
> --- a/gdb/tui/tui-io.c
> +++ b/gdb/tui/tui-io.c
> @@ -678,8 +678,9 @@ tui_getc (FILE *fp)
>          }
>        else
>          {
> +          /* Move cursor to the end of the command line.  */
>            wmove (w, TUI_CMD_WIN->detail.command_info.cur_line,
> -                 TUI_CMD_WIN->detail.command_info.curch);
> +		 strlen (tui_rl_saved_prompt) + rl_end);
>            waddch (w, ch);

Does this still do the right thing with secondary prompts?

E.g., if you do "quit" while a program is running, and then
press enter a few times just to have the query repeat (and
then pagination kick in, for extra stress).

Thanks,
Pedro Alves

Re: [PATCH] Fix truncation of TUI command history

[Patrick Palka]

On Thu, Sep 4, 2014 at 5:44 AM, Pedro Alves <palves@redhat.com> wrote:
> Hi Patrick,
>
> On 08/30/2014 07:11 PM, Patrick Palka wrote:
>> index aa14790..eee5f1ac6 100644
>> --- a/gdb/tui/tui-io.c
>> +++ b/gdb/tui/tui-io.c
>> @@ -678,8 +678,9 @@ tui_getc (FILE *fp)
>>          }
>>        else
>>          {
>> +          /* Move cursor to the end of the command line.  */
>>            wmove (w, TUI_CMD_WIN->detail.command_info.cur_line,
>> -                 TUI_CMD_WIN->detail.command_info.curch);
>> +              strlen (tui_rl_saved_prompt) + rl_end);
>>            waddch (w, ch);
>
> Does this still do the right thing with secondary prompts?
>
> E.g., if you do "quit" while a program is running, and then
> press enter a few times just to have the query repeat (and
> then pagination kick in, for extra stress).
>
> Thanks,
> Pedro Alves
>

Good point.  It doesn't work correctly in this case.  I'll try to find
a better solution.

Re: [PATCH] Fix truncation of TUI command history

[Pedro Alves]

On 01/10/2015 03:49 AM, Patrick Palka wrote:

> We need to move the cursor because
> when ncurses outputs a newline it truncates any text that appears
> past the end of the cursor.

Can you merge this sentence into the comment in the code?

>        else
>          {
> -          wmove (w, TUI_CMD_WIN->detail.command_info.cur_line,
> -                 TUI_CMD_WIN->detail.command_info.curch);
> -          waddch (w, ch);
> +	  /* Move cursor to the end of the command line before emitting the
> +	     newline.  */

... as this as is doesn't explain _why_ we need to do that, which
may make the reader wonder.

> +	  int px = TUI_CMD_WIN->detail.command_info.curch;
> +	  int py = TUI_CMD_WIN->detail.command_info.cur_line;
> +	  px += rl_end - rl_point;
> +	  py += px / TUI_CMD_WIN->generic.width;
> +	  px %= TUI_CMD_WIN->generic.width;
> +	  wmove (w, py, px);
> +	  waddch (w, ch);
>          }
>      }
>    
> 

OK with that change.  Thanks!

Thanks,
Pedro Alves

Re: [PATCH] Fix truncation of TUI command history

[Patrick Palka]

Ping.

Re: [PATCH] Fix truncation of TUI command history

[Patrick Palka]

Ping.

Re: [PATCH] Fix truncation of TUI command history

[Patrick Palka]

This is an improved variant of the patch here
https://sourceware.org/ml/gdb-patches/2014-09/msg00109.html that also
works properly for secondary prompts (and overlong lines).

[PATCH] Fix truncation of TUI command history

[Patrick Palka]

If we submit a command while the prompt cursor is somewhere other than
at the end of the command line, the command line gets truncated as the
command window gets shifted one line up.  This happens because we fail
to properly move the cursor to the end of the command line before
transmitting the newline to ncurses.  We need to move the cursor because
when ncurses outputs a newline it truncates any text that appears
past the end of the cursor.

The fix is generic enough to work properly even in multi-line secondary
prompts like the quit prompt.

gdb/ChangeLog:

	* tui/tui-io.c (tui_getc): Move cursor to the end of the command
	line before printing a newline.
---
 gdb/tui/tui-io.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index 73dbcfc..94c3ec2 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -708,9 +708,15 @@ tui_getc (FILE *fp)
         }
       else
         {
-          wmove (w, TUI_CMD_WIN->detail.command_info.cur_line,
-                 TUI_CMD_WIN->detail.command_info.curch);
-          waddch (w, ch);
+	  /* Move cursor to the end of the command line before emitting the
+	     newline.  */
+	  int px = TUI_CMD_WIN->detail.command_info.curch;
+	  int py = TUI_CMD_WIN->detail.command_info.cur_line;
+	  px += rl_end - rl_point;
+	  py += px / TUI_CMD_WIN->generic.width;
+	  px %= TUI_CMD_WIN->generic.width;
+	  wmove (w, py, px);
+	  waddch (w, ch);
         }
     }
   
-- 
2.2.1.212.gc5b9256