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>

9 files changed, 52 insertions, 19 deletions

diff --git a/qapi/block-core.json b/qapi/block-core.json
index ff8e2ba0cb..6866ae8a38 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2273,15 +2273,14 @@
 # besides their data source and an optional backing file.
 #
 # @backing:     reference to or definition of the backing file block
-#               device (if missing, taken from the image file content). It is
-#               allowed to pass an empty string here in order to disable the
-#               default backing file.
+#               device, null disables the backing file entirely.
+#               Defaults to the backing file stored the image file.
 #
 # Since: 2.9
 ##
 { 'struct': 'BlockdevOptionsGenericCOWFormat',
   'base': 'BlockdevOptionsGenericFormat',
-  'data': { '*backing': 'BlockdevRef' } }
+  'data': { '*backing': 'BlockdevRefOrNull' } }
 
 ##
 # @Qcow2OverlapCheckMode:
@@ -3120,9 +3119,7 @@
 # Reference to a block device.
 #
 # @definition:      defines a new block device inline
-# @reference:       references the ID of an existing block device. An
-#                   empty string means that no block device should be
-#                   referenced.
+# @reference:       references the ID of an existing block device
 #
 # Since: 2.9
 ##
@@ -3131,6 +3128,24 @@
             'reference': 'str' } }
 
 ##
+# @BlockdevRefOrNull:
+#
+# Reference to a block device.
+#
+# @definition:      defines a new block device inline
+# @reference:       references the ID of an existing block device.
+#                   An empty string means that no block device should
+#                   be referenced.  Deprecated; use null instead.
+# @null:            No block device should be referenced (since 2.10)
+#
+# Since: 2.9
+##
+{ 'alternate': 'BlockdevRefOrNull',
+  'data': { 'definition': 'BlockdevOptions',
+            'reference': 'str',
+            'null': 'null' } }
+
+##
 # @blockdev-add:
 #
 # Creates a new block device. If the @id option is given at the top level, a
diff --git a/qapi/qapi-clone-visitor.c b/qapi/qapi-clone-visitor.c
index ed16d3a17f..d8b62792bc 100644
--- a/qapi/qapi-clone-visitor.c
+++ b/qapi/qapi-clone-visitor.c
@@ -127,12 +127,13 @@ static void qapi_clone_type_number(Visitor *v, const char *name, double *obj,
     /* Value was already cloned by g_memdup() */
 }
 
-static void qapi_clone_type_null(Visitor *v, const char *name, Error **errp)
+static void qapi_clone_type_null(Visitor *v, const char *name, QNull **obj,
+                                 Error **errp)
 {
     QapiCloneVisitor *qcv = to_qcv(v);
 
     assert(qcv->depth);
-    /* Nothing to do */
+    *obj = qnull();
 }
 
 static void qapi_clone_free(Visitor *v)
diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c
index fd6f9fb61c..ed70a0158b 100644
--- a/qapi/qapi-dealloc-visitor.c
+++ b/qapi/qapi-dealloc-visitor.c
@@ -103,8 +103,12 @@ static void qapi_dealloc_type_anything(Visitor *v, const char *name,
     }
 }
 
-static void qapi_dealloc_type_null(Visitor *v, const char *name, Error **errp)
+static void qapi_dealloc_type_null(Visitor *v, const char *name,
+                                   QNull **obj, Error **errp)
 {
+    if (obj) {
+        QDECREF(*obj);
+    }
 }
 
 static void qapi_dealloc_free(Visitor *v)
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index 935a2c5bc9..ed6d2af462 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -325,10 +325,11 @@ void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp)
     error_propagate(errp, err);
 }
 
-void visit_type_null(Visitor *v, const char *name, Error **errp)
+void visit_type_null(Visitor *v, const char *name, QNull **obj,
+                     Error **errp)
 {
-    trace_visit_type_null(v, name);
-    v->type_null(v, name, errp);
+    trace_visit_type_null(v, name, obj);
+    v->type_null(v, name, obj, errp);
 }
 
 static void output_type_enum(Visitor *v, const char *name, int *obj,
diff --git a/qapi/qobject-input-visitor.c b/qapi/qobject-input-visitor.c
index 35aff78f2b..ee9e47d911 100644
--- a/qapi/qobject-input-visitor.c
+++ b/qapi/qobject-input-visitor.c
@@ -587,11 +587,13 @@ static void qobject_input_type_any(Visitor *v, const char *name, QObject **obj,
     *obj = qobj;
 }
 
-static void qobject_input_type_null(Visitor *v, const char *name, Error **errp)
+static void qobject_input_type_null(Visitor *v, const char *name,
+                                    QNull **obj, Error **errp)
 {
     QObjectInputVisitor *qiv = to_qiv(v);
     QObject *qobj = qobject_input_get_object(qiv, name, true, errp);
 
+    *obj = NULL;
     if (!qobj) {
         return;
     }
@@ -599,7 +601,9 @@ static void qobject_input_type_null(Visitor *v, const char *name, Error **errp)
     if (qobject_type(qobj) != QTYPE_QNULL) {
         error_setg(errp, QERR_INVALID_PARAMETER_TYPE,
                    full_name(qiv, name), "null");
+        return;
     }
+    *obj = qnull();
 }
 
 static void qobject_input_type_size_keyval(Visitor *v, const char *name,
diff --git a/qapi/qobject-output-visitor.c b/qapi/qobject-output-visitor.c
index 70be84ccb5..d325163e55 100644
--- a/qapi/qobject-output-visitor.c
+++ b/qapi/qobject-output-visitor.c
@@ -187,10 +187,11 @@ static void qobject_output_type_any(Visitor *v, const char *name,
     qobject_output_add_obj(qov, name, *obj);
 }
 
-static void qobject_output_type_null(Visitor *v, const char *name, Error **errp)
+static void qobject_output_type_null(Visitor *v, const char *name,
+                                     QNull **obj, Error **errp)
 {
     QObjectOutputVisitor *qov = to_qov(v);
-    qobject_output_add_obj(qov, name, qnull());
+    qobject_output_add(qov, name, qnull());
 }
 
 /* Finish building, and return the root object.
diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c
index 63ae115b2a..67a0a4a58b 100644
--- a/qapi/string-input-visitor.c
+++ b/qapi/string-input-visitor.c
@@ -326,14 +326,20 @@ static void parse_type_number(Visitor *v, const char *name, double *obj,
     *obj = val;
 }
 
-static void parse_type_null(Visitor *v, const char *name, Error **errp)
+static void parse_type_null(Visitor *v, const char *name, QNull **obj,
+                            Error **errp)
 {
     StringInputVisitor *siv = to_siv(v);
 
+    *obj = NULL;
+
     if (!siv->string || siv->string[0]) {
         error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
                    "null");
+        return;
     }
+
+    *obj = qnull();
 }
 
 static void string_input_free(Visitor *v)
diff --git a/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
index af649e1d6e..7ab64468d9 100644
--- a/qapi/string-output-visitor.c
+++ b/qapi/string-output-visitor.c
@@ -256,7 +256,8 @@ static void print_type_number(Visitor *v, const char *name, double *obj,
     string_output_set(sov, g_strdup_printf("%f", *obj));
 }
 
-static void print_type_null(Visitor *v, const char *name, Error **errp)
+static void print_type_null(Visitor *v, const char *name, QNull **obj,
+                            Error **errp)
 {
     StringOutputVisitor *sov = to_sov(v);
     char *out;
diff --git a/qapi/trace-events b/qapi/trace-events
index 3b57abaa37..9e9008a1dc 100644
--- a/qapi/trace-events
+++ b/qapi/trace-events
@@ -31,4 +31,4 @@ visit_type_bool(void *v, const char *name, bool *obj) "v=%p name=%s obj=%p"
 visit_type_str(void *v, const char *name, char **obj) "v=%p name=%s obj=%p"
 visit_type_number(void *v, const char *name, double *obj) "v=%p name=%s obj=%p"
 visit_type_any(void *v, const char *name, void *obj) "v=%p name=%s obj=%p"
-visit_type_null(void *v, const char *name) "v=%p name=%s"
+visit_type_null(void *v, const char *name, void *obj) "v=%p name=%s obj=%p"