Re: [PATCH] Restore terminal state in mi_thread_exit (PR gdb/17627)

[Sergio Durigan Junior <sergiodj@redhat.com>]

On Tuesday, November 25 2014, Simon Marchi wrote:

> When a thread exits, the terminal is left in mode "terminal_is_ours"
> while the target executes. This patch fixes that.
>
> From my understanding, a function calling target_terminal_ours expects
> that the terminal could be in any state at the moment it is called.
> Therefore, it should be its reponsibility to put back the terminal in
> whatever state it was before being called.
>
> I find that this fits quite well the cleanup model, so I implemented a
> cleanup for that.

Thanks for the patch.  A few comments related to the coding style and
cleanups.

> gdb/ChangeLog:
>
> 2014-11-25  Simon Marchi  <simon.marchi@ericsson.com>
>
> 	PR gdb/17627
> 	* target.c (cleanup_restore_target_terminal): New function.
> 	(make_cleanup_restore_target_terminal): New function.
> 	* target.h (make_cleanup_restore_target_terminal): New
> 	declaration.
> 	* mi/mi-interp.c (mi_thread_exit): Use the new cleanup.
>
> Signed-off-by: Simon Marchi <simon.marchi@ericsson.com>
> ---
>  gdb/mi/mi-interp.c |  4 ++++
>  gdb/target.c       | 30 ++++++++++++++++++++++++++++++
>  gdb/target.h       |  4 ++++
>  3 files changed, 38 insertions(+)
>
> diff --git a/gdb/mi/mi-interp.c b/gdb/mi/mi-interp.c
> index df2b558..2a62e22 100644
> --- a/gdb/mi/mi-interp.c
> +++ b/gdb/mi/mi-interp.c
> @@ -386,6 +386,7 @@ mi_thread_exit (struct thread_info *t, int silent)
>  {
>    struct mi_interp *mi;
>    struct inferior *inf;
> +  struct cleanup *old_chain;
>  
>    if (silent)
>      return;
> @@ -393,11 +394,14 @@ mi_thread_exit (struct thread_info *t, int silent)
>    inf = find_inferior_pid (ptid_get_pid (t->ptid));
>  
>    mi = top_level_interpreter_data ();
> +  old_chain = make_cleanup_restore_target_terminal();

Space between function name and ().

>    target_terminal_ours ();
>    fprintf_unfiltered (mi->event_channel, 
>  		      "thread-exited,id=\"%d\",group-id=\"i%d\"",
>  		      t->num, inf->num);
>    gdb_flush (mi->event_channel);
> +
> +  do_cleanups(old_chain);

Likewise.

>  }
>  
>  /* Emit notification on changing the state of record.  */
> diff --git a/gdb/target.c b/gdb/target.c
> index ab5f2b9..d6a06bd 100644
> --- a/gdb/target.c
> +++ b/gdb/target.c
> @@ -528,6 +528,36 @@ target_supports_terminal_ours (void)
>    return 0;
>  }
>  
> +static void cleanup_restore_target_terminal (void *arg)
              ^
Break the line here.

New functions should have a comment describing them.

> +{
> +  enum terminal_state *previous_state = arg;
> +
> +  switch (*previous_state)
> +  {
> +    case terminal_is_ours:
> +      target_terminal_ours();
> +      break;
> +    case terminal_is_ours_for_output:
> +      target_terminal_ours_for_output();
> +      break;
> +    case terminal_is_inferior:
> +      target_terminal_inferior();
> +      break;

The "case" should be indented below the "{".

Missing whitespace between function names and ().

> +  }
> +
> +  xfree(previous_state);

Likewise.

> +}
> +
> +struct cleanup *
> +make_cleanup_restore_target_terminal (void)

Missing function comment.  Since you already described this one on the
header file, you can just say:

  /* See definition in target.h.  */

> +{
> +  enum terminal_state *ts = xmalloc(sizeof(*ts));

Whitespace between function name and ().

> +
> +  *ts = terminal_state;
> +
> +  return make_cleanup (cleanup_restore_target_terminal, ts);

You should use make_cleanup_dtor here, because "ts" may leak if the
cleanup is not called.

> +}
> +
>  static void
>  tcomplain (void)
>  {
> diff --git a/gdb/target.h b/gdb/target.h
> index d363b61..a1c3b7b 100644
> --- a/gdb/target.h
> +++ b/gdb/target.h
> @@ -1413,6 +1413,10 @@ extern void target_terminal_ours (void);
>  
>  extern int target_supports_terminal_ours (void);
>  
> +/* Make a cleanup that restores the state of the terminal to the current
> + * value. */

You just need to use "*" after and before the "/" in comments:

  /* This is a
     multi-line
     comment.  */

It's also missing two spaces after period.

> +extern struct cleanup *make_cleanup_restore_target_terminal (void);
> +
>  /* Print useful information about our terminal status, if such a thing
>     exists.  */
>  
> -- 
> 2.1.3

-- 
Sergio
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