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.
v2: Incorporated feedback from Stefan Hajnoczi Signed-off-by: Mike Day <ncm...@ncultra.org> --- 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; + + 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); + 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