qapi script: clean up in scripts

This patch improve docs and uses c_type(argentry, is_param=True)
in script.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

docs/qapi-code-gen.txt

@@ -218,10 +218,10 @@ An example command is:
 === Events ===
 
 Events are defined with the keyword 'event'.  When 'data' is also specified,
-additional info will be carried on.  Finally there will be C API generated
-in qapi-event.h; when called by QEMU code, a message with timestamp will
-be emitted on the wire.  If timestamp is -1, it means failure to retrieve host
-time.
+additional info will be included in the event.  Finally there will be C API
+generated in qapi-event.h; when called by QEMU code, a message with timestamp
+will be emitted on the wire.  If timestamp is -1, it means failure to retrieve
+host time.
 
 An example event is:
 

scripts/qapi-event.py

@@ -26,9 +26,8 @@ def _generate_event_api_name(event_name, params):
                 api_name += "bool has_%s,\n" % c_var(argname)
                 api_name += "".ljust(l)
 
-            if argentry == "str":
-                api_name += "const "
-            api_name += "%s %s,\n" % (c_type(argentry), c_var(argname))
+            api_name += "%s %s,\n" % (c_type(argentry, is_param=True),
+                                      c_var(argname))
             api_name += "".ljust(l)
 
     api_name += "Error **errp)"

scripts/qapi.py

@@ -255,7 +255,7 @@ def check_event(expr, expr_info):
             if structured:
                 raise QAPIExprError(expr_info,
                                     "Nested structure define in event is not "
-                                    "supported now, event '%s', argname '%s'"
+                                    "supported, event '%s', argname '%s'"
                                     % (expr['event'], argname))
 
 def check_union(expr, expr_info):

tests/qapi-schema/event-nest-struct.err

@@ -1 +1 @@
-tests/qapi-schema/event-nest-struct.json:1: Nested structure define in event is not supported now, event 'EVENT_A', argname 'a'
+tests/qapi-schema/event-nest-struct.json:1: Nested structure define in event is not supported, event 'EVENT_A', argname 'a'