[RFA,v2,06/24] Change open_terminal_stream to return a gdb_file_up

  This changes open_terminal_stream to return a gdb_file_up, eliminating
another use of make_cleanup_fclose.  Arguably perhaps new_ui should
take ownership of the files using a move, but there is at least one
spot where this isn't appropriate (or at least not currently done), so
I elected to use a more minimal approach.

ChangeLog
2017-07-25  Tom Tromey  <tom@tromey.com>

	* top.c (open_terminal_stream): Return gdb_file_up.
	(new_ui_command): Update.
---
 gdb/ChangeLog |  5 +++++
 gdb/top.c     | 24 ++++++++++++------------
 2 files changed, 17 insertions(+), 12 deletions(-)
  

On 2017-07-25 19:20, Tom Tromey wrote:
> This changes open_terminal_stream to return a gdb_file_up, eliminating
> another use of make_cleanup_fclose.  Arguably perhaps new_ui should
> take ownership of the files using a move, but there is at least one
> spot where this isn't appropriate (or at least not currently done), so
> I elected to use a more minimal approach.
> 
> ChangeLog
> 2017-07-25  Tom Tromey  <tom@tromey.com>
> 
> 	* top.c (open_terminal_stream): Return gdb_file_up.
> 	(new_ui_command): Update.
> ---
>  gdb/ChangeLog |  5 +++++
>  gdb/top.c     | 24 ++++++++++++------------
>  2 files changed, 17 insertions(+), 12 deletions(-)
> 
> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
> index 4c23f79..c1730dd 100644
> --- a/gdb/ChangeLog
> +++ b/gdb/ChangeLog
> @@ -1,5 +1,10 @@
>  2017-07-25  Tom Tromey  <tom@tromey.com>
> 
> +	* top.c (open_terminal_stream): Return gdb_file_up.
> +	(new_ui_command): Update.
> +
> +2017-07-25  Tom Tromey  <tom@tromey.com>
> +
>  	* source.c (print_source_lines_base, forward_search_command)
>  	(reverse_search_command): Use gdb_file_up.
> 
> diff --git a/gdb/top.c b/gdb/top.c
> index 4c53efd..2504eb6 100644
> --- a/gdb/top.c
> +++ b/gdb/top.c
> @@ -346,16 +346,16 @@ make_delete_ui_cleanup (struct ui *ui)
>  /* Open file named NAME for read/write, making sure not to make it the
>     controlling terminal.  */
> 
> -static FILE *
> +static gdb_file_up
>  open_terminal_stream (const char *name)
>  {
>    int fd;
> 
> -  fd = open (name, O_RDWR | O_NOCTTY);
> +  fd = gdb_open_cloexec (name, O_RDWR | O_NOCTTY, 0);
>    if (fd < 0)
>      perror_with_name  (_("opening terminal failed"));
> 
> -  return fdopen (fd, "w+");
> +  return gdb_file_up (fdopen (fd, "w+"));
>  }
> 
>  /* Implementation of the "new-ui" command.  */
> @@ -365,7 +365,7 @@ new_ui_command (char *args, int from_tty)
>  {
>    struct ui *ui;
>    struct interp *interp;
> -  FILE *stream[3] = { NULL, NULL, NULL };
> +  gdb_file_up stream[3];
>    int i;
>    int res;
>    int argc;
> @@ -390,18 +390,13 @@ new_ui_command (char *args, int from_tty)
>    {
>      scoped_restore save_ui = make_scoped_restore (&current_ui);
> 
> -    failure_chain = make_cleanup (null_cleanup, NULL);
> -
>      /* Open specified terminal, once for each of
>         stdin/stdout/stderr.  */
>      for (i = 0; i < 3; i++)
> -      {
> -	stream[i] = open_terminal_stream (tty_name);
> -	make_cleanup_fclose (stream[i]);
> -      }
> +      stream[i] = open_terminal_stream (tty_name);
> 
> -    ui = new_ui (stream[0], stream[1], stream[2]);
> -    make_cleanup (delete_ui_cleanup, ui);
> +    ui = new_ui (stream[0].get (), stream[1].get (), stream[2].get 
> ());
> +    failure_chain = make_cleanup (delete_ui_cleanup, ui);
> 
>      ui->async = 1;
> 
> @@ -411,6 +406,11 @@ new_ui_command (char *args, int from_tty)
> 
>      interp_pre_command_loop (top_level_interpreter ());
> 
> +    /* Make sure the files are not closed.  */
> +    stream[0].release ();
> +    stream[1].release ();
> +    stream[2].release ();
> +
>      discard_cleanups (failure_chain);
> 
>      /* This restores the previous UI and frees argv.  */

LGTM.