When a block driver supports obtaining format-specific information, but
that object only contains optional fields, it is possible that none of
them are present, so that dump_qobject() (called by
bdrv_image_info_specific_dump()) will not print anything.
The callers of bdrv_image_info_specific_dump() put a header above this
information ("Format specific information:\n"), which will look strange
when there is nothing below. Modify bdrv_image_info_specific_dump() to
print this header instead of its callers, and only if there is indeed
something to be printed.
Signed-off-by: Hanna Reitz <hre...@redhat.com>
---
include/block/qapi.h | 3 ++-
block/qapi.c | 41 +++++++++++++++++++++++++++++++++++++----
qemu-io-cmds.c | 4 ++--
3 files changed, 41 insertions(+), 7 deletions(-)
diff --git a/include/block/qapi.h b/include/block/qapi.h
index 22c7807c89..c09859ea78 100644
--- a/include/block/qapi.h
+++ b/include/block/qapi.h
@@ -40,6 +40,7 @@ void bdrv_query_image_info(BlockDriverState *bs,
Error **errp);
void bdrv_snapshot_dump(QEMUSnapshotInfo *sn);
-void bdrv_image_info_specific_dump(ImageInfoSpecific *info_spec);
+void bdrv_image_info_specific_dump(ImageInfoSpecific *info_spec,
+ const char *prefix);
void bdrv_image_info_dump(ImageInfo *info);
#endif
diff --git a/block/qapi.c b/block/qapi.c
index cf557e3aea..51202b470a 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -777,7 +777,35 @@ static void dump_qdict(int indentation, QDict *dict)
}
}
-void bdrv_image_info_specific_dump(ImageInfoSpecific *info_spec)
+/*
+ * Return whether dumping the given QObject with dump_qobject() would
+ * yield an empty dump, i.e. not print anything.
+ */
+static bool qobject_is_empty_dump(const QObject *obj)
+{
+ switch (qobject_type(obj)) {
+ case QTYPE_QNUM:
+ case QTYPE_QSTRING:
+ case QTYPE_QBOOL:
+ return false;
+
+ case QTYPE_QDICT:
+ return qdict_size(qobject_to(QDict, obj)) == 0;
+
+ case QTYPE_QLIST:
+ return qlist_empty(qobject_to(QList, obj));
+
+ default:
+ abort();
+ }
+}
+
+/**
+ * Dumps the given ImageInfoSpecific object in a human-readable form,
+ * prepending an optional prefix if the dump is not empty.
+ */
+void bdrv_image_info_specific_dump(ImageInfoSpecific *info_spec,
+ const char *prefix)
{
QObject *obj, *data;
Visitor *v = qobject_output_visitor_new(&obj);
@@ -785,7 +813,12 @@ void bdrv_image_info_specific_dump(ImageInfoSpecific
*info_spec)
visit_type_ImageInfoSpecific(v, NULL, &info_spec, &error_abort);
visit_complete(v, &obj);
data = qdict_get(qobject_to(QDict, obj), "data");
- dump_qobject(1, data);
+ if (!qobject_is_empty_dump(data)) {
+ if (prefix) {
+ qemu_printf("%s", prefix);
+ }
+ dump_qobject(1, data);
+ }
qobject_unref(obj);
visit_free(v);
}
@@ -866,7 +899,7 @@ void bdrv_image_info_dump(ImageInfo *info)
}
if (info->has_format_specific) {
- qemu_printf("Format specific information:\n");
- bdrv_image_info_specific_dump(info->format_specific);
+ bdrv_image_info_specific_dump(info->format_specific,
+ "Format specific information:\n");
}
}
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 2f0d8ac25a..084ec44d3b 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -1819,8 +1819,8 @@ static int info_f(BlockBackend *blk, int argc, char
**argv)
return -EIO;
}
if (spec_info) {
- printf("Format specific information:\n");
- bdrv_image_info_specific_dump(spec_info);
+ bdrv_image_info_specific_dump(spec_info,
+ "Format specific information:\n");
qapi_free_ImageInfoSpecific(spec_info);
}
--
2.35.3
