Re: [Qemu-devel] [PATCH] [v2 PATCH] qemu-img: sort block formats in help message

[Fam Zheng <famz@redhat.com>]

On Mon, 05/05 12:53, Mike Day wrote:
> The help message for qemu-img lists the supported block formats, of
> which there are 27 as of version 2.0.50. The formats are printed in
> the order of their driver's position in a linked list, which appears
> random. This patch prints the formats in sorted order, making it
> easier to read and to find a specific format in the list.
> 

Revision note should go below --- , so the line won't get into the commit log
when maintainers apply the patch, like:

> 
> Signed-off-by: Mike Day <ncmike@ncultra.org>
> ---

v2: Incorporated feedback from Stefan Hajnoczi

>  qemu-img.c | 27 ++++++++++++++++++++++++---
>  1 file changed, 24 insertions(+), 3 deletions(-)
> 
> diff --git a/qemu-img.c b/qemu-img.c
> index 96f4463..a559108 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -32,6 +32,7 @@
>  #include "block/block_int.h"
>  #include "block/qapi.h"
>  #include <getopt.h>
> +#include <glib.h>
>  
>  #define QEMU_IMG_VERSION "qemu-img version " QEMU_VERSION \
>                            ", Copyright (c) 2004-2008 Fabrice Bellard\n"
> @@ -55,9 +56,25 @@ typedef enum OutputFormat {
>  #define BDRV_O_FLAGS BDRV_O_CACHE_WB
>  #define BDRV_DEFAULT_CACHE "writeback"
>  
> -static void format_print(void *opaque, const char *name)
> +static gint compare_data(gconstpointer a, gconstpointer b, gpointer user)
>  {
> -    printf(" %s", name);
> +    return g_strcmp0(a, b);
> +}
> +
> +static void print_format(gpointer data, gpointer user)
> +{
> +    printf(" %s", (char *)data);
> +}
> +
> +static void add_format_to_seq(void *opaque, const char *fmt_name)
> +{
> +    GSequence *seq = (GSequence *)opaque;

Stefan pointed in comments for v1:

       GSequence *seq = opaque;

> +
> +    if (!g_sequence_lookup(seq, (gpointer)fmt_name,
> +                           compare_data, NULL)) {
> +        g_sequence_insert_sorted(seq, (gpointer)fmt_name,
> +                                 compare_data, NULL);
> +    }
>  }
>  
>  static void QEMU_NORETURN GCC_FMT_ATTR(1, 2) error_exit(const char *fmt, ...)
> @@ -144,8 +161,12 @@ static void QEMU_NORETURN help(void)
>             "  '-s' run in Strict mode - fail on different image size or sector allocation\n";
>  
>      printf("%s\nSupported formats:", help_msg);
> -    bdrv_iterate_format(format_print, NULL);
> +    GSequence *seq = g_sequence_new(NULL);

Let's put this variable declaration above statements, or move the printf above
down.

Thanks,
Fam

> +    bdrv_iterate_format(add_format_to_seq, seq);
> +    g_sequence_foreach(seq, print_format, NULL);
>      printf("\n");
> +    g_sequence_free(seq);
> +
>      exit(EXIT_SUCCESS);
>  }
>  
> -- 
> 1.9.0
> 
>