qapi block: Elide redundant has_FOO in generated C

The has_FOO for pointer-valued FOO are redundant, except for arrays.
They are also a nuisance to work with.  Recent commit "qapi: Start to
elide redundant has_FOO in generated C" provided the means to elide
them step by step.  This is the step for qapi/block*.json.

Said commit explains the transformation in more detail.

There is one instance of the invariant violation mentioned there:
qcow2_signal_corruption() passes false, "" when node_name is an empty
string.  Take care to pass NULL then.

The previous two commits cleaned up two more.

Additionally, helper bdrv_latency_histogram_stats() loses its output
parameters and returns a value instead.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Hanna Reitz <hreitz@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20221104160712.3005652-11-armbru@redhat.com>
[Fixes for #ifndef LIBRBD_SUPPORTS_ENCRYPTION and MacOS squashed in]

1 files changed, 6 insertions, 7 deletions

diff --git a/qemu-img.c b/qemu-img.c
index a9b3a8103c..439d8de1e3 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2915,15 +2915,15 @@ static ImageInfoList *collect_image_info_list(bool image_opts,
         image_opts = false;
 
         if (chain) {
-            if (info->has_full_backing_filename) {
+            if (info->full_backing_filename) {
                 filename = info->full_backing_filename;
-            } else if (info->has_backing_filename) {
+            } else if (info->backing_filename) {
                 error_report("Could not determine absolute backing filename,"
                              " but backing filename '%s' present",
                              info->backing_filename);
                 goto err;
             }
-            if (info->has_backing_filename_format) {
+            if (info->backing_filename_format) {
                 fmt = info->backing_filename_format;
             }
         }
@@ -3046,7 +3046,7 @@ static int dump_map_entry(OutputFormat output_format, MapEntry *e,
             printf("%#-16"PRIx64"%#-16"PRIx64"%#-16"PRIx64"%s\n",
                    e->start, e->length,
                    e->has_offset ? e->offset : 0,
-                   e->has_filename ? e->filename : "");
+                   e->filename ?: "");
         }
         /* This format ignores the distinction between 0, ZERO and ZERO|DATA.
          * Modify the flags here to allow more coalescing.
@@ -3127,7 +3127,6 @@ static int get_block_status(BlockDriverState *bs, int64_t offset,
         .has_offset = has_offset,
         .depth = depth,
         .present = !!(ret & BDRV_BLOCK_ALLOCATED),
-        .has_filename = filename,
         .filename = filename,
     };
 
@@ -3143,11 +3142,11 @@ static inline bool entry_mergeable(const MapEntry *curr, const MapEntry *next)
         curr->data != next->data ||
         curr->depth != next->depth ||
         curr->present != next->present ||
-        curr->has_filename != next->has_filename ||
+        !curr->filename != !next->filename ||
         curr->has_offset != next->has_offset) {
         return false;
     }
-    if (curr->has_filename && strcmp(curr->filename, next->filename)) {
+    if (curr->filename && strcmp(curr->filename, next->filename)) {
         return false;
     }
     if (curr->has_offset && curr->offset + curr->length != next->offset) {