[Libguestfs] [PATCH] btrfs-qgroup-show: add check for "--raw"

[Pino Toscano]

On Sunday 15 March 2015 23:08:07 Chen Hanxiao wrote:
> btrfs-prog commit:
> 58a39524619f38d193b8adc3d57888ec07b612aa
> change the default output to binary prefix,
> and introduced a new option '--raw'
> to keep the traditional behaviour.
> 
> This patch will add a check function to determine
> whether to add '--raw' option to 'btrfs show qgroup'.
> 
> Signed-off-by: Chen Hanxiao <chenhanxiao at cn.fujitsu.com>
> ---
>  daemon/btrfs.c | 33 +++++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/daemon/btrfs.c b/daemon/btrfs.c
> index d4b3207..ddaf15b 100644
> --- a/daemon/btrfs.c
> +++ b/daemon/btrfs.c
> @@ -1210,12 +1210,43 @@ do_btrfs_qgroup_destroy (const char *qgroupid, const char *subvolume)
>    return 0;
>  }
>  
> +/* btrfs qgroup show command change default output to
> + * binary prefix since v3.18.2, such as KiB;
> + * also introduced '--raw' to keep traditional behaviour.
> + * We could check wheter 'btrfs qgroup show' support '--raw'
> + * option by checking the output of
> + * 'btrfs qgroup show' support --help' command.
> + */
> +static int
> +test_btrfs_qgroup_show_raw_opt (void)
> +{
> +  static int result = -1;
> +  if (result > 0)
> +    return result;

This should check for result != -1, otherwise if --raw is not supported
this function will be run fully (i.e. executing `btrfs`) every time.

> +  CLEANUP_FREE char *err = NULL;
> +  CLEANUP_FREE char *out = NULL;
> +
> +  int r = commandr (&out, &err, str_btrfs, "qgroup", "show", "--help", NULL);
> +
> +  if (r == -1) {
> +    reply_with_error ("btrfs qgroup show --help: %s", err);
> +    return -1;
> +  }
> +
> +  if (!strstr (out, "--raw"))

!foo -> foo == NULL (clearer).

>  guestfs_int_btrfsqgroup_list *
>  do_btrfs_qgroup_show (const char *path)
>  {
>    const size_t MAX_ARGS = 64;
>    const char *argv[MAX_ARGS];
>    size_t i = 0;
> +  int btrfs_qgroup_show_raw_opt = test_btrfs_qgroup_show_raw_opt ();

Maybe a shorter name for the local variable will suffice? Something
like has_raw_opt.

>    CLEANUP_FREE char *path_buf = NULL;
>    CLEANUP_FREE char *err = NULL;
>    CLEANUP_FREE char *out = NULL;
> @@ -1231,6 +1262,8 @@ do_btrfs_qgroup_show (const char *path)
>    ADD_ARG (argv, i, str_btrfs);
>    ADD_ARG (argv, i, "qgroup");
>    ADD_ARG (argv, i, "show");
> +  if (btrfs_qgroup_show_raw_opt)
> +    ADD_ARG (argv, i, "--raw");

This should check for > 0, otherwise it will add --raw also when it was
not possible to determine whether --raw is supported (i.e. when the
value is -1).

Thanks,
-- 
Pino Toscano