[Qemu-devel] [PATCH v6 21/23] qapi: Simplify extra member error reporting in input visitors

[Eric Blake <eblake@redhat.com>]

When reporting that an unvisited member remains at the end of an
input visit for a struct, we were using g_hash_table_find()
coupled with a callback function that always returns true, to
locate an arbitrary member of the hash table.  But if all we
need is one entry, we can get that from a single iteration on an
iterator, without needing to split logic to a callback function.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

---
v6: new patch, based on comments on RFC against v5 7/46
---
 qapi/opts-visitor.c      | 12 +++---------
 qapi/qmp-input-visitor.c | 14 +++++---------
 2 files changed, 8 insertions(+), 18 deletions(-)

diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c
index 37f172d..46dd9fe 100644
--- a/qapi/opts-visitor.c
+++ b/qapi/opts-visitor.c
@@ -150,17 +150,11 @@ opts_start_struct(Visitor *v, void **obj, const char *kind,
 }


-static gboolean
-ghr_true(gpointer ign_key, gpointer ign_value, gpointer ign_user_data)
-{
-    return TRUE;
-}
-
-
 static void
 opts_end_struct(Visitor *v, Error **errp)
 {
     OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
+    GHashTableIter iter;
     GQueue *any;

     if (--ov->depth > 0) {
@@ -168,8 +162,8 @@ opts_end_struct(Visitor *v, Error **errp)
     }

     /* we should have processed all (distinct) QemuOpt instances */
-    any = g_hash_table_find(ov->unprocessed_opts, &ghr_true, NULL);
-    if (any) {
+    g_hash_table_iter_init(&iter, ov->unprocessed_opts);
+    if (g_hash_table_iter_next(&iter, NULL, (void **)&any)) {
         const QemuOpt *first;

         first = g_queue_peek_head(any);
diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index 9ff1e75..9dbe025 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -88,12 +88,6 @@ static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp)
     qiv->nb_stack++;
 }

-/** Only for qmp_input_pop. */
-static gboolean always_true(gpointer key, gpointer val, gpointer user_pkey)
-{
-    *(const char **)user_pkey = (const char *)key;
-    return TRUE;
-}

 static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp)
 {
@@ -102,9 +96,11 @@ static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp)
     if (qiv->strict) {
         GHashTable * const top_ht = qiv->stack[qiv->nb_stack - 1].h;
         if (top_ht) {
-            if (g_hash_table_size(top_ht)) {
-                const char *key;
-                g_hash_table_find(top_ht, always_true, &key);
+            GHashTableIter iter;
+            const char *key;
+
+            g_hash_table_iter_init(&iter, top_ht);
+            if (g_hash_table_iter_next(&iter, (void **)&key, NULL)) {
                 error_setg(errp, QERR_QMP_EXTRA_MEMBER, key);
             }
             g_hash_table_unref(top_ht);
-- 
2.4.3