[Qemu-devel] [PATCH v2 13/25] monitor: add 'async' capability

[Marc-André Lureau]

Declare that the server supports async.

Check if the client supports it: the following patch will suspend the
qmp monitor if an async command is ongoing but the client doesn't
support async.

Signed-off-by: Marc-André Lureau <address@hidden>
---
 qapi-schema.json            | 16 ++++++++++++++--
 include/qapi/qmp/dispatch.h |  1 +
 monitor.c                   | 19 ++++++++++++++++---
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/qapi-schema.json b/qapi-schema.json
index ddc878390e..8366206415 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -72,11 +72,23 @@
 ##
 
 ##
+# @QMPCapability:
+#
+# QMP protocol capabilities
+#
+# @async: enables async messages
+#
+# Since: 2.9
+##
+{ 'enum': 'QMPCapability',
+  'data': ['async'] }
+
+##
 # @qmp_capabilities:
 #
 # Enable QMP capabilities.
 #
-# Arguments: None.
+# @capabilities: #optional an array of @QMPCapability (since 2.9)
 #
 # Example:
 #
@@ -90,7 +102,7 @@
 # Since: 0.13
 #
 ##
-{ 'command': 'qmp_capabilities' }
+{ 'command': 'qmp_capabilities', 'data': { '*capabilities': ['QMPCapability'] 
} }
 
 ##
 # @LostTickPolicy:
diff --git a/include/qapi/qmp/dispatch.h b/include/qapi/qmp/dispatch.h
index e13e381834..4dd6de5ab2 100644
--- a/include/qapi/qmp/dispatch.h
+++ b/include/qapi/qmp/dispatch.h
@@ -32,6 +32,7 @@ struct QmpClient {
     QmpDispatchReturn *return_cb;
 
     QLIST_HEAD(, QmpReturn) pending;
+    bool has_async;             /* the client has async capability */
 };
 
 typedef void (QmpCommandFunc)(QDict *, QObject **, Error **);
diff --git a/monitor.c b/monitor.c
index 98ba40b573..585f7b6a1a 100644
--- a/monitor.c
+++ b/monitor.c
@@ -563,9 +563,22 @@ static void monitor_qapi_event_init(void)
     qmp_event_set_func_emit(monitor_qapi_event_queue);
 }
 
-void qmp_qmp_capabilities(Error **errp)
+void qmp_qmp_capabilities(bool has_capabilities,
+                          QMPCapabilityList *capabilities, Error **errp)
 {
+    bool has_async = false;
+
+    if (has_capabilities) {
+        while (capabilities) {
+            if (capabilities->value == QMP_CAPABILITY_ASYNC) {
+                has_async = true;
+            }
+            capabilities = capabilities->next;
+        }
+    }
+
     cur_mon->qmp.in_command_mode = true;
+    cur_mon->qmp.client.has_async = has_async;
 }
 
 static void handle_hmp_command(Monitor *mon, const char *cmdline);
@@ -3845,8 +3858,8 @@ static QObject *get_qmp_greeting(void)
 
     qmp_marshal_query_version(NULL, &ver, NULL);
 
-    return qobject_from_jsonf("{'QMP': {'version': %p, 'capabilities': []}}",
-                              ver);
+    return qobject_from_jsonf("{'QMP': {'version': %p, 'capabilities': ["
+                              "'async']}}", ver);
 }
 
 static void monitor_qmp_event(void *opaque, int event)
-- 
2.11.0.295.gd7dffce1c