From 91fa93e516d080d440ead2ad4f88960545bd5b2c Mon Sep 17 00:00:00 2001
From: Markus Armbruster
Date: Thu, 18 Mar 2021 16:55:11 +0100
Subject: qapi: Implement deprecated-output=hide for QMP command results

This policy suppresses deprecated bits in output, and thus permits
"testing the future".  Implement it for QMP command results.  Example:
when QEMU is run with -compat deprecated-output=hide, then

    {"execute": "query-cpus-fast"}

yields

    {"return": [{"thread-id": 9805, "props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "qom-path": "/machine/unattached/device[0]", "cpu-index": 0, "target": "x86_64"}]}

instead of

    {"return": [{"arch": "x86", "thread-id": 22436, "props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "qom-path": "/machine/unattached/device[0]", "cpu-index": 0, "target": "x86_64"}]}

Note the suppression of deprecated member "arch".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210318155519.1224118-4-armbru@redhat.com>
---
 include/qapi/compat-policy.h          | 9 +++++++++
 include/qapi/qobject-output-visitor.h | 4 ++++
 include/qapi/visitor-impl.h           | 3 +++
 include/qapi/visitor.h                | 9 +++++++++
 4 files changed, 25 insertions(+)

(limited to 'include')

diff --git a/include/qapi/compat-policy.h b/include/qapi/compat-policy.h
index b8c6638156..94c8bbd790 100644
--- a/include/qapi/compat-policy.h
+++ b/include/qapi/compat-policy.h
@@ -17,4 +17,13 @@
 
 extern CompatPolicy compat_policy;
 
+/*
+ * Create a QObject output visitor for @obj for use with QMP
+ *
+ * This is like qobject_output_visitor_new(), except it obeys the
+ * policy for handling deprecated management interfaces set with
+ * -compat.
+ */
+Visitor *qobject_output_visitor_new_qmp(QObject **result);
+
 #endif
diff --git a/include/qapi/qobject-output-visitor.h b/include/qapi/qobject-output-visitor.h
index 2b1726baf5..f2a2f92a00 100644
--- a/include/qapi/qobject-output-visitor.h
+++ b/include/qapi/qobject-output-visitor.h
@@ -15,6 +15,7 @@
 #define QOBJECT_OUTPUT_VISITOR_H
 
 #include "qapi/visitor.h"
+#include "qapi/qapi-types-compat.h"
 
 typedef struct QObjectOutputVisitor QObjectOutputVisitor;
 
@@ -53,4 +54,7 @@ typedef struct QObjectOutputVisitor QObjectOutputVisitor;
  */
 Visitor *qobject_output_visitor_new(QObject **result);
 
+void qobject_output_visitor_set_policy(Visitor *v,
+                                       CompatPolicyOutput deprecated);
+
 #endif
diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
index 7362c043be..2d853255a3 100644
--- a/include/qapi/visitor-impl.h
+++ b/include/qapi/visitor-impl.h
@@ -113,6 +113,9 @@ struct Visitor
        The core takes care of the return type in the public interface. */
     void (*optional)(Visitor *v, const char *name, bool *present);
 
+    /* Optional */
+    bool (*deprecated)(Visitor *v, const char *name);
+
     /* Must be set */
     VisitorType type;
 
diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h
index ebc19ede7f..4d23b59853 100644
--- a/include/qapi/visitor.h
+++ b/include/qapi/visitor.h
@@ -459,6 +459,15 @@ void visit_end_alternate(Visitor *v, void **obj);
  */
 bool visit_optional(Visitor *v, const char *name, bool *present);
 
+/*
+ * Should we visit deprecated member @name?
+ *
+ * @name must not be NULL.  This function is only useful between
+ * visit_start_struct() and visit_end_struct(), since only objects
+ * have deprecated members.
+ */
+bool visit_deprecated(Visitor *v, const char *name);
+
 /*
  * Visit an enum value.
  *
-- 
cgit v1.2.3-55-g7522