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Re: [PATCH v2] qcow2: Use a GString in report_unsupported_feature()
From: |
Stefano Garzarella |
Subject: |
Re: [PATCH v2] qcow2: Use a GString in report_unsupported_feature() |
Date: |
Thu, 16 Jan 2020 11:40:50 +0100 |
On Wed, Jan 15, 2020 at 02:56:26PM +0100, Alberto Garcia wrote:
> This is a bit more efficient than having to allocate and free memory
> for each item.
>
> The default size (60) is enough for all the existing incompatible
> features or the "Unknown incompatible feature" message.
>
> Suggested-by: Philippe Mathieu-Daudé <address@hidden>
> Signed-off-by: Alberto Garcia <address@hidden>
> Reviewed-by: Alex Bennée <address@hidden>
> ---
> block/qcow2.c | 23 +++++++++++------------
> 1 file changed, 11 insertions(+), 12 deletions(-)
Reviewed-by: Stefano Garzarella <address@hidden>
>
> v2: Use g_autoptr and update commit message
>
> diff --git a/block/qcow2.c b/block/qcow2.c
> index cef9d72b3a..e29fc07068 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -453,16 +453,15 @@ static void cleanup_unknown_header_ext(BlockDriverState
> *bs)
> static void report_unsupported_feature(Error **errp, Qcow2Feature *table,
> uint64_t mask)
> {
> - char *features = g_strdup("");
> - char *old;
> + g_autoptr(GString) features = g_string_sized_new(60);
>
> while (table && table->name[0] != '\0') {
> if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) {
> if (mask & (1ULL << table->bit)) {
> - old = features;
> - features = g_strdup_printf("%s%s%.46s", old, *old ? ", " :
> "",
> - table->name);
> - g_free(old);
> + if (features->len > 0) {
> + g_string_append(features, ", ");
> + }
> + g_string_append_printf(features, "%.46s", table->name);
> mask &= ~(1ULL << table->bit);
> }
> }
> @@ -470,14 +469,14 @@ static void report_unsupported_feature(Error **errp,
> Qcow2Feature *table,
> }
>
> if (mask) {
> - old = features;
> - features = g_strdup_printf("%s%sUnknown incompatible feature: %"
> PRIx64,
> - old, *old ? ", " : "", mask);
> - g_free(old);
> + if (features->len > 0) {
> + g_string_append(features, ", ");
> + }
> + g_string_append_printf(features,
> + "Unknown incompatible feature: %" PRIx64,
> mask);
> }
>
> - error_setg(errp, "Unsupported qcow2 feature(s): %s", features);
> - g_free(features);
> + error_setg(errp, "Unsupported qcow2 feature(s): %s", features->str);
> }
>
> /*
> --
> 2.20.1
>
>