qapi: Plumb in 'boxed' to qapi generator lower levels

The next patch will add support for passing a qapi union type
as the 'data' of a command.  But to do that, the user function
for implementing the command, as called by the generated
marshal command, must take the corresponding C struct as a
single boxed pointer, rather than a breakdown into one
parameter per member.  Even without a union, being able to use
a C struct rather than a list of parameters can make it much
easier to handle coding with QAPI.

This patch adds the internal plumbing of a 'boxed' flag
associated with each command and event.  In several cases,
this means adding indentation, with one new dead branch and
the remaining branch being the original code more deeply
nested; this was done so that the new implementation in the
next patch is easier to review without also being mixed with
indentation changes.

For this patch, no behavior or generated output changes, other
than the testsuite outputting the value of the new flag
(always False for now).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1468468228-27827-9-git-send-email-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Identifier box renamed to boxed in two places]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

4 files changed, 49 insertions, 36 deletions

diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index 333a46f623..0090fb4f21 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -16,20 +16,22 @@ from qapi import *
 import re
 
 
-def gen_command_decl(name, arg_type, ret_type):
+def gen_command_decl(name, arg_type, boxed, ret_type):
     return mcgen('''
 %(c_type)s qmp_%(c_name)s(%(params)s);
 ''',
                  c_type=(ret_type and ret_type.c_type()) or 'void',
                  c_name=c_name(name),
-                 params=gen_params(arg_type, 'Error **errp'))
+                 params=gen_params(arg_type, boxed, 'Error **errp'))
 
 
-def gen_call(name, arg_type, ret_type):
+def gen_call(name, arg_type, boxed, ret_type):
     ret = ''
 
     argstr = ''
-    if arg_type:
+    if boxed:
+        assert False    # not implemented
+    elif arg_type:
         assert not arg_type.variants
         for memb in arg_type.members:
             if memb.optional:
@@ -94,7 +96,7 @@ def gen_marshal_decl(name):
                  proto=gen_marshal_proto(name))
 
 
-def gen_marshal(name, arg_type, ret_type):
+def gen_marshal(name, arg_type, boxed, ret_type):
     ret = mcgen('''
 
 %(proto)s
@@ -136,7 +138,7 @@ def gen_marshal(name, arg_type, ret_type):
     (void)args;
 ''')
 
-    ret += gen_call(name, arg_type, ret_type)
+    ret += gen_call(name, arg_type, boxed, ret_type)
 
     # 'goto out' produced above for arg_type, and by gen_call() for ret_type
     if (arg_type and not arg_type.is_empty()) or ret_type:
@@ -212,16 +214,16 @@ class QAPISchemaGenCommandVisitor(QAPISchemaVisitor):
         self._visited_ret_types = None
 
     def visit_command(self, name, info, arg_type, ret_type,
-                      gen, success_response):
+                      gen, success_response, boxed):
         if not gen:
             return
-        self.decl += gen_command_decl(name, arg_type, ret_type)
+        self.decl += gen_command_decl(name, arg_type, boxed, ret_type)
         if ret_type and ret_type not in self._visited_ret_types:
             self._visited_ret_types.add(ret_type)
             self.defn += gen_marshal_output(ret_type)
         if middle_mode:
             self.decl += gen_marshal_decl(name)
-        self.defn += gen_marshal(name, arg_type, ret_type)
+        self.defn += gen_marshal(name, arg_type, boxed, ret_type)
         if not middle_mode:
             self._regy += gen_register_command(name, success_response)
 
diff --git a/scripts/qapi-event.py b/scripts/qapi-event.py
index b9c6b6efdf..53410c26d5 100644
--- a/scripts/qapi-event.py
+++ b/scripts/qapi-event.py
@@ -14,18 +14,18 @@
 from qapi import *
 
 
-def gen_event_send_proto(name, arg_type):
+def gen_event_send_proto(name, arg_type, boxed):
     return 'void qapi_event_send_%(c_name)s(%(param)s)' % {
         'c_name': c_name(name.lower()),
-        'param': gen_params(arg_type, 'Error **errp')}
+        'param': gen_params(arg_type, boxed, 'Error **errp')}
 
 
-def gen_event_send_decl(name, arg_type):
+def gen_event_send_decl(name, arg_type, boxed):
     return mcgen('''
 
 %(proto)s;
 ''',
-                 proto=gen_event_send_proto(name, arg_type))
+                 proto=gen_event_send_proto(name, arg_type, boxed))
 
 
 # Declare and initialize an object 'qapi' using parameters from gen_params()
@@ -57,7 +57,7 @@ def gen_param_var(typ):
     return ret
 
 
-def gen_event_send(name, arg_type):
+def gen_event_send(name, arg_type, boxed):
     # FIXME: Our declaration of local variables (and of 'errp' in the
     # parameter list) can collide with exploded members of the event's
     # data type passed in as parameters.  If this collision ever hits in
@@ -72,7 +72,7 @@ def gen_event_send(name, arg_type):
     Error *err = NULL;
     QMPEventFuncEmit emit;
 ''',
-                proto=gen_event_send_proto(name, arg_type))
+                proto=gen_event_send_proto(name, arg_type, boxed))
 
     if arg_type and not arg_type.is_empty():
         ret += mcgen('''
@@ -160,9 +160,9 @@ class QAPISchemaGenEventVisitor(QAPISchemaVisitor):
         self.defn += gen_enum_lookup(event_enum_name, self._event_names)
         self._event_names = None
 
-    def visit_event(self, name, info, arg_type):
-        self.decl += gen_event_send_decl(name, arg_type)
-        self.defn += gen_event_send(name, arg_type)
+    def visit_event(self, name, info, arg_type, boxed):
+        self.decl += gen_event_send_decl(name, arg_type, boxed)
+        self.defn += gen_event_send(name, arg_type, boxed)
         self._event_names.append(name)
 
 
diff --git a/scripts/qapi-introspect.py b/scripts/qapi-introspect.py
index e0f926be04..541644e350 100644
--- a/scripts/qapi-introspect.py
+++ b/scripts/qapi-introspect.py
@@ -154,14 +154,14 @@ const char %(c_name)s[] = %(c_string)s;
                                     for m in variants.variants]})
 
     def visit_command(self, name, info, arg_type, ret_type,
-                      gen, success_response):
+                      gen, success_response, boxed):
         arg_type = arg_type or self._schema.the_empty_object_type
         ret_type = ret_type or self._schema.the_empty_object_type
         self._gen_json(name, 'command',
                        {'arg-type': self._use_type(arg_type),
                         'ret-type': self._use_type(ret_type)})
 
-    def visit_event(self, name, info, arg_type):
+    def visit_event(self, name, info, arg_type, boxed):
         arg_type = arg_type or self._schema.the_empty_object_type
         self._gen_json(name, 'event', {'arg-type': self._use_type(arg_type)})
 
diff --git a/scripts/qapi.py b/scripts/qapi.py
index 9c48f6d80a..0c6159c400 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -826,10 +826,10 @@ class QAPISchemaVisitor(object):
         pass
 
     def visit_command(self, name, info, arg_type, ret_type,
-                      gen, success_response):
+                      gen, success_response, boxed):
         pass
 
-    def visit_event(self, name, info, arg_type):
+    def visit_event(self, name, info, arg_type, boxed):
         pass
 
 
@@ -1165,7 +1165,8 @@ class QAPISchemaAlternateType(QAPISchemaType):
 
 
 class QAPISchemaCommand(QAPISchemaEntity):
-    def __init__(self, name, info, arg_type, ret_type, gen, success_response):
+    def __init__(self, name, info, arg_type, ret_type, gen, success_response,
+                 boxed):
         QAPISchemaEntity.__init__(self, name, info)
         assert not arg_type or isinstance(arg_type, str)
         assert not ret_type or isinstance(ret_type, str)
@@ -1175,12 +1176,14 @@ class QAPISchemaCommand(QAPISchemaEntity):
         self.ret_type = None
         self.gen = gen
         self.success_response = success_response
+        self.boxed = boxed
 
     def check(self, schema):
         if self._arg_type_name:
             self.arg_type = schema.lookup_type(self._arg_type_name)
             assert isinstance(self.arg_type, QAPISchemaObjectType)
             assert not self.arg_type.variants   # not implemented
+            assert not self.boxed               # not implemented
         if self._ret_type_name:
             self.ret_type = schema.lookup_type(self._ret_type_name)
             assert isinstance(self.ret_type, QAPISchemaType)
@@ -1188,24 +1191,26 @@ class QAPISchemaCommand(QAPISchemaEntity):
     def visit(self, visitor):
         visitor.visit_command(self.name, self.info,
                               self.arg_type, self.ret_type,
-                              self.gen, self.success_response)
+                              self.gen, self.success_response, self.boxed)
 
 
 class QAPISchemaEvent(QAPISchemaEntity):
-    def __init__(self, name, info, arg_type):
+    def __init__(self, name, info, arg_type, boxed):
         QAPISchemaEntity.__init__(self, name, info)
         assert not arg_type or isinstance(arg_type, str)
         self._arg_type_name = arg_type
         self.arg_type = None
+        self.boxed = boxed
 
     def check(self, schema):
         if self._arg_type_name:
             self.arg_type = schema.lookup_type(self._arg_type_name)
             assert isinstance(self.arg_type, QAPISchemaObjectType)
             assert not self.arg_type.variants   # not implemented
+            assert not self.boxed               # not implemented
 
     def visit(self, visitor):
-        visitor.visit_event(self.name, self.info, self.arg_type)
+        visitor.visit_event(self.name, self.info, self.arg_type, self.boxed)
 
 
 class QAPISchema(object):
@@ -1381,6 +1386,7 @@ class QAPISchema(object):
         rets = expr.get('returns')
         gen = expr.get('gen', True)
         success_response = expr.get('success-response', True)
+        boxed = expr.get('boxed', False)
         if isinstance(data, OrderedDict):
             data = self._make_implicit_object_type(
                 name, info, 'arg', self._make_members(data, info))
@@ -1388,15 +1394,16 @@ class QAPISchema(object):
             assert len(rets) == 1
             rets = self._make_array_type(rets[0], info)
         self._def_entity(QAPISchemaCommand(name, info, data, rets, gen,
-                                           success_response))
+                                           success_response, boxed))
 
     def _def_event(self, expr, info):
         name = expr['event']
         data = expr.get('data')
+        boxed = expr.get('boxed', False)
         if isinstance(data, OrderedDict):
             data = self._make_implicit_object_type(
                 name, info, 'arg', self._make_members(data, info))
-        self._def_entity(QAPISchemaEvent(name, info, data))
+        self._def_entity(QAPISchemaEvent(name, info, data, boxed))
 
     def _def_exprs(self):
         for expr_elem in self.exprs:
@@ -1639,18 +1646,22 @@ extern const char *const %(c_name)s_lookup[];
     return ret
 
 
-def gen_params(arg_type, extra):
+def gen_params(arg_type, boxed, extra):
     if not arg_type:
         return extra
-    assert not arg_type.variants
     ret = ''
     sep = ''
-    for memb in arg_type.members:
-        ret += sep
-        sep = ', '
-        if memb.optional:
-            ret += 'bool has_%s, ' % c_name(memb.name)
-        ret += '%s %s' % (memb.type.c_param_type(), c_name(memb.name))
+    if boxed:
+        assert False     # not implemented
+    else:
+        assert not arg_type.variants
+        for memb in arg_type.members:
+            ret += sep
+            sep = ', '
+            if memb.optional:
+                ret += 'bool has_%s, ' % c_name(memb.name)
+            ret += '%s %s' % (memb.type.c_param_type(),
+                              c_name(memb.name))
     if extra:
         ret += sep + extra
     return ret