scripts/qapi/events.py

   1 """
   2 QAPI event generator
   3
   4 Copyright (c) 2014 Wenchao Xia
   5 Copyright (c) 2015-2018 Red Hat Inc.
   6
   7 Authors:
   8  Wenchao Xia <wenchaoqemu@gmail.com>
   9  Markus Armbruster <armbru@redhat.com>
  10
  11 This work is licensed under the terms of the GNU GPL, version 2.
  12 See the COPYING file in the top-level directory.
  13 """
  14
  15 from typing import List, Optional
  16
  17 from .common import c_enum_const, c_name, mcgen
  18 from .gen import QAPISchemaModularCVisitor, build_params, ifcontext
  19 from .schema import (
  20     QAPISchema,
  21     QAPISchemaEnumMember,
  22     QAPISchemaFeature,
  23     QAPISchemaIfCond,
  24     QAPISchemaObjectType,
  25 )
  26 from .source import QAPISourceInfo
  27 from .types import gen_enum, gen_enum_lookup
  28
  29
  30 def build_event_send_proto(name: str,
  31                            arg_type: Optional[QAPISchemaObjectType],
  32                            boxed: bool) -> str:
  33     return 'void qapi_event_send_%(c_name)s(%(param)s)' % {
  34         'c_name': c_name(name.lower()),
  35         'param': build_params(arg_type, boxed)}
  36
  37
  38 def gen_event_send_decl(name: str,
  39                         arg_type: Optional[QAPISchemaObjectType],
  40                         boxed: bool) -> str:
  41     return mcgen('''
  42
  43 %(proto)s;
  44 ''',
  45                  proto=build_event_send_proto(name, arg_type, boxed))
  46
  47
  48 def gen_param_var(typ: QAPISchemaObjectType) -> str:
  49     """
  50     Generate a struct variable holding the event parameters.
  51
  52     Initialize it with the function arguments defined in `gen_event_send`.
  53     """
  54     assert not typ.variants
  55     ret = mcgen('''
  56     %(c_name)s param = {
  57 ''',
  58                 c_name=typ.c_name())
  59     sep = '        '
  60     for memb in typ.members:
  61         ret += sep
  62         sep = ', '
  63         if memb.optional:
  64             ret += 'has_' + c_name(memb.name) + sep
  65         if memb.type.name == 'str':
  66             # Cast away const added in build_params()
  67             ret += '(char *)'
  68         ret += c_name(memb.name)
  69     ret += mcgen('''
  70
  71     };
  72 ''')
  73     if not typ.is_implicit():
  74         ret += mcgen('''
  75     %(c_name)s *arg = &param;
  76 ''',
  77                      c_name=typ.c_name())
  78     return ret
  79
  80
  81 def gen_event_send(name: str,
  82                    arg_type: Optional[QAPISchemaObjectType],
  83                    features: List[QAPISchemaFeature],
  84                    boxed: bool,
  85                    event_enum_name: str,
  86                    event_emit: str) -> str:
  87     # FIXME: Our declaration of local variables (and of 'errp' in the
  88     # parameter list) can collide with exploded members of the event's
  89     # data type passed in as parameters.  If this collision ever hits in
  90     # practice, we can rename our local variables with a leading _ prefix,
  91     # or split the code into a wrapper function that creates a boxed
  92     # 'param' object then calls another to do the real work.
  93     have_args = boxed or (arg_type and not arg_type.is_empty())
  94
  95     ret = mcgen('''
  96
  97 %(proto)s
  98 {
  99     QDict *qmp;
 100 ''',
 101                 proto=build_event_send_proto(name, arg_type, boxed))
 102
 103     if have_args:
 104         assert arg_type is not None
 105         ret += mcgen('''
 106     QObject *obj;
 107     Visitor *v;
 108 ''')
 109         if not boxed:
 110             ret += gen_param_var(arg_type)
 111
 112     if 'deprecated' in [f.name for f in features]:
 113         ret += mcgen('''
 114
 115     if (compat_policy.deprecated_output == COMPAT_POLICY_OUTPUT_HIDE) {
 116         return;
 117     }
 118 ''')
 119
 120     ret += mcgen('''
 121
 122     qmp = qmp_event_build_dict("%(name)s");
 123
 124 ''',
 125                  name=name)
 126
 127     if have_args:
 128         assert arg_type is not None
 129         ret += mcgen('''
 130     v = qobject_output_visitor_new_qmp(&obj);
 131 ''')
 132         if not arg_type.is_implicit():
 133             ret += mcgen('''
 134     visit_type_%(c_name)s(v, "%(name)s", &arg, &error_abort);
 135 ''',
 136                          name=name, c_name=arg_type.c_name())
 137         else:
 138             ret += mcgen('''
 139
 140     visit_start_struct(v, "%(name)s", NULL, 0, &error_abort);
 141     visit_type_%(c_name)s_members(v, &param, &error_abort);
 142     visit_check_struct(v, &error_abort);
 143     visit_end_struct(v, NULL);
 144 ''',
 145                          name=name, c_name=arg_type.c_name())
 146         ret += mcgen('''
 147
 148     visit_complete(v, &obj);
 149     if (qdict_size(qobject_to(QDict, obj))) {
 150         qdict_put_obj(qmp, "data", obj);
 151     } else {
 152         qobject_unref(obj);
 153     }
 154 ''')
 155
 156     ret += mcgen('''
 157     %(event_emit)s(%(c_enum)s, qmp);
 158
 159 ''',
 160                  event_emit=event_emit,
 161                  c_enum=c_enum_const(event_enum_name, name))
 162
 163     if have_args:
 164         ret += mcgen('''
 165     visit_free(v);
 166 ''')
 167     ret += mcgen('''
 168     qobject_unref(qmp);
 169 }
 170 ''')
 171     return ret
 172
 173
 174 class QAPISchemaGenEventVisitor(QAPISchemaModularCVisitor):
 175
 176     def __init__(self, prefix: str):
 177         super().__init__(
 178             prefix, 'qapi-events',
 179             ' * Schema-defined QAPI/QMP events', None, __doc__)
 180         self._event_enum_name = c_name(prefix + 'QAPIEvent', protect=False)
 181         self._event_enum_members: List[QAPISchemaEnumMember] = []
 182         self._event_emit_name = c_name(prefix + 'qapi_event_emit')
 183
 184     def _begin_user_module(self, name: str) -> None:
 185         events = self._module_basename('qapi-events', name)
 186         types = self._module_basename('qapi-types', name)
 187         visit = self._module_basename('qapi-visit', name)
 188         self._genc.add(mcgen('''
 189 #include "qemu/osdep.h"
 190 #include "%(prefix)sqapi-emit-events.h"
 191 #include "%(events)s.h"
 192 #include "%(visit)s.h"
 193 #include "qapi/compat-policy.h"
 194 #include "qapi/error.h"
 195 #include "qapi/qmp/qdict.h"
 196 #include "qapi/qmp-event.h"
 197
 198 ''',
 199                              events=events, visit=visit,
 200                              prefix=self._prefix))
 201         self._genh.add(mcgen('''
 202 #include "qapi/util.h"
 203 #include "%(types)s.h"
 204 ''',
 205                              types=types))
 206
 207     def visit_end(self) -> None:
 208         self._add_module('./emit', ' * QAPI Events emission')
 209         self._genc.preamble_add(mcgen('''
 210 #include "qemu/osdep.h"
 211 #include "%(prefix)sqapi-emit-events.h"
 212 ''',
 213                                       prefix=self._prefix))
 214         self._genh.preamble_add(mcgen('''
 215 #include "qapi/util.h"
 216 '''))
 217         self._genh.add(gen_enum(self._event_enum_name,
 218                                 self._event_enum_members))
 219         self._genc.add(gen_enum_lookup(self._event_enum_name,
 220                                        self._event_enum_members))
 221         self._genh.add(mcgen('''
 222
 223 void %(event_emit)s(%(event_enum)s event, QDict *qdict);
 224 ''',
 225                              event_emit=self._event_emit_name,
 226                              event_enum=self._event_enum_name))
 227
 228     def visit_event(self,
 229                     name: str,
 230                     info: Optional[QAPISourceInfo],
 231                     ifcond: QAPISchemaIfCond,
 232                     features: List[QAPISchemaFeature],
 233                     arg_type: Optional[QAPISchemaObjectType],
 234                     boxed: bool) -> None:
 235         with ifcontext(ifcond, self._genh, self._genc):
 236             self._genh.add(gen_event_send_decl(name, arg_type, boxed))
 237             self._genc.add(gen_event_send(name, arg_type, features, boxed,
 238                                           self._event_enum_name,
 239                                           self._event_emit_name))
 240         # Note: we generate the enum member regardless of @ifcond, to
 241         # keep the enumeration usable in target-independent code.
 242         self._event_enum_members.append(QAPISchemaEnumMember(name, None))
 243
 244
 245 def gen_events(schema: QAPISchema,
 246                output_dir: str,
 247                prefix: str) -> None:
 248     vis = QAPISchemaGenEventVisitor(prefix)
 249     schema.visit(vis)
 250     vis.write(output_dir)