Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2017-07-18-v2' into staging

QAPI patches for 2017-07-18

# gpg: Signature made Mon 24 Jul 2017 12:40:56 BST
# gpg:                using RSA key 0x3870B400EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>"
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>"
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2017-07-18-v2:
  migration: Use JSON null instead of "" to reset parameter to default
  migration: Unshare MigrationParameters struct for now
  migration: Add TODO comments on duplication of QAPI_CLONE()
  migration: Clean up around tls_creds, tls_hostname
  hmp: Clean up and simplify hmp_migrate_set_parameter()
  block: Use JSON null instead of "" to disable backing file
  tests/test-qobject-input-visitor: Drop redundant test
  qapi: Introduce a first class 'null' type
  qapi: Use QNull for a more regular visit_type_null()
  qapi: Separate type QNull from QObject

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 14 insertions, 8 deletions

diff --git a/include/qapi/qmp/qobject.h b/include/qapi/qmp/qobject.h
index b8ddbca405..eab29edd12 100644
--- a/include/qapi/qmp/qobject.h
+++ b/include/qapi/qmp/qobject.h
@@ -93,11 +93,15 @@ static inline QType qobject_type(const QObject *obj)
     return obj->type;
 }
 
-extern QObject qnull_;
+struct QNull {
+    QObject base;
+};
+
+extern QNull qnull_;
 
-static inline QObject *qnull(void)
+static inline QNull *qnull(void)
 {
-    qobject_incref(&qnull_);
+    QINCREF(&qnull_);
     return &qnull_;
 }
 
diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
index dcd656ab76..8ccb3b6c20 100644
--- a/include/qapi/visitor-impl.h
+++ b/include/qapi/visitor-impl.h
@@ -103,7 +103,8 @@ struct Visitor
                      Error **errp);
 
     /* Must be set to visit explicit null values.  */
-    void (*type_null)(Visitor *v, const char *name, Error **errp);
+    void (*type_null)(Visitor *v, const char *name, QNull **obj,
+                      Error **errp);
 
     /* Must be set for input visitors to visit structs, optional otherwise.
        The core takes care of the return type in the public interface. */
diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h
index 74768aabda..fe9faf469f 100644
--- a/include/qapi/visitor.h
+++ b/include/qapi/visitor.h
@@ -618,10 +618,10 @@ void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp);
  * @name expresses the relationship of the null value to its parent
  * container; see the general description of @name above.
  *
- * Unlike all other visit_type_* functions, no obj parameter is
- * needed; rather, this is a witness that an explicit null value is
- * expected rather than any other type.
+ * @obj must be non-NULL.  Input visitors set *@obj to the value;
+ * other visitors ignore *@obj.
  */
-void visit_type_null(Visitor *v, const char *name, Error **errp);
+void visit_type_null(Visitor *v, const char *name, QNull **obj,
+                     Error **errp);
 
 #endif
diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
index 7b0d4e7e05..39bc8351a3 100644
--- a/include/qemu/typedefs.h
+++ b/include/qemu/typedefs.h
@@ -89,6 +89,7 @@ typedef struct QEMUSGList QEMUSGList;
 typedef struct QEMUTimer QEMUTimer;
 typedef struct QEMUTimerListGroup QEMUTimerListGroup;
 typedef struct QObject QObject;
+typedef struct QNull QNull;
 typedef struct RAMBlock RAMBlock;
 typedef struct Range Range;
 typedef struct SerialState SerialState;