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