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     for f in features:
 113         if f.is_special():
 114             ret += mcgen('''
 115
 116     if (compat_policy.%(feat)s_output == COMPAT_POLICY_OUTPUT_HIDE) {
 117         return;
 118     }
 119 ''',
 120                          feat=f.name)
 121
 122     ret += mcgen('''
 123
 124     qmp = qmp_event_build_dict("%(name)s");
 125
 126 ''',
 127                  name=name)
 128
 129     if have_args:
 130         assert arg_type is not None
 131         ret += mcgen('''
 132     v = qobject_output_visitor_new_qmp(&obj);
 133 ''')
 134         if not arg_type.is_implicit():
 135             ret += mcgen('''
 136     visit_type_%(c_name)s(v, "%(name)s", &arg, &error_abort);
 137 ''',
 138                          name=name, c_name=arg_type.c_name())
 139         else:
 140             ret += mcgen('''
 141
 142     visit_start_struct(v, "%(name)s", NULL, 0, &error_abort);
 143     visit_type_%(c_name)s_members(v, &param, &error_abort);
 144     visit_check_struct(v, &error_abort);
 145     visit_end_struct(v, NULL);
 146 ''',
 147                          name=name, c_name=arg_type.c_name())
 148         ret += mcgen('''
 149
 150     visit_complete(v, &obj);
 151     if (qdict_size(qobject_to(QDict, obj))) {
 152         qdict_put_obj(qmp, "data", obj);
 153     } else {
 154         qobject_unref(obj);
 155     }
 156 ''')
 157
 158     ret += mcgen('''
 159     %(event_emit)s(%(c_enum)s, qmp);
 160
 161 ''',
 162                  event_emit=event_emit,
 163                  c_enum=c_enum_const(event_enum_name, name))
 164
 165     if have_args:
 166         ret += mcgen('''
 167     visit_free(v);
 168 ''')
 169     ret += mcgen('''
 170     qobject_unref(qmp);
 171 }
 172 ''')
 173     return ret
 174
 175
 176 class QAPISchemaGenEventVisitor(QAPISchemaModularCVisitor):
 177
 178     def __init__(self, prefix: str):
 179         super().__init__(
 180             prefix, 'qapi-events',
 181             ' * Schema-defined QAPI/QMP events', None, __doc__)
 182         self._event_enum_name = c_name(prefix + 'QAPIEvent', protect=False)
 183         self._event_enum_members: List[QAPISchemaEnumMember] = []
 184         self._event_emit_name = c_name(prefix + 'qapi_event_emit')
 185
 186     def _begin_user_module(self, name: str) -> None:
 187         events = self._module_basename('qapi-events', name)
 188         types = self._module_basename('qapi-types', name)
 189         visit = self._module_basename('qapi-visit', name)
 190         self._genc.add(mcgen('''
 191 #include "qemu/osdep.h"
 192 #include "%(prefix)sqapi-emit-events.h"
 193 #include "%(events)s.h"
 194 #include "%(visit)s.h"
 195 #include "qapi/compat-policy.h"
 196 #include "qapi/error.h"
 197 #include "qapi/qmp/qdict.h"
 198 #include "qapi/qmp-event.h"
 199
 200 ''',
 201                              events=events, visit=visit,
 202                              prefix=self._prefix))
 203         self._genh.add(mcgen('''
 204 #include "qapi/util.h"
 205 #include "%(types)s.h"
 206 ''',
 207                              types=types))
 208
 209     def visit_end(self) -> None:
 210         self._add_module('./emit', ' * QAPI Events emission')
 211         self._genc.preamble_add(mcgen('''
 212 #include "qemu/osdep.h"
 213 #include "%(prefix)sqapi-emit-events.h"
 214 ''',
 215                                       prefix=self._prefix))
 216         self._genh.preamble_add(mcgen('''
 217 #include "qapi/util.h"
 218 '''))
 219         self._genh.add(gen_enum(self._event_enum_name,
 220                                 self._event_enum_members))
 221         self._genc.add(gen_enum_lookup(self._event_enum_name,
 222                                        self._event_enum_members))
 223         self._genh.add(mcgen('''
 224
 225 void %(event_emit)s(%(event_enum)s event, QDict *qdict);
 226 ''',
 227                              event_emit=self._event_emit_name,
 228                              event_enum=self._event_enum_name))
 229
 230     def visit_event(self,
 231                     name: str,
 232                     info: Optional[QAPISourceInfo],
 233                     ifcond: QAPISchemaIfCond,
 234                     features: List[QAPISchemaFeature],
 235                     arg_type: Optional[QAPISchemaObjectType],
 236                     boxed: bool) -> None:
 237         with ifcontext(ifcond, self._genh, self._genc):
 238             self._genh.add(gen_event_send_decl(name, arg_type, boxed))
 239             self._genc.add(gen_event_send(name, arg_type, features, boxed,
 240                                           self._event_enum_name,
 241                                           self._event_emit_name))
 242         # Note: we generate the enum member regardless of @ifcond, to
 243         # keep the enumeration usable in target-independent code.
 244         self._event_enum_members.append(QAPISchemaEnumMember(name, None))
 245
 246
 247 def gen_events(schema: QAPISchema,
 248                output_dir: str,
 249                prefix: str) -> None:
 250     vis = QAPISchemaGenEventVisitor(prefix)
 251     schema.visit(vis)
 252     vis.write(output_dir)