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                    boxed: bool,
  83                    event_enum_name: str,
  84                    event_emit: str) -> str:
  85     # FIXME: Our declaration of local variables (and of 'errp' in the
  86     # parameter list) can collide with exploded members of the event's
  87     # data type passed in as parameters.  If this collision ever hits in
  88     # practice, we can rename our local variables with a leading _ prefix,
  89     # or split the code into a wrapper function that creates a boxed
  90     # 'param' object then calls another to do the real work.
  91     have_args = boxed or (arg_type and not arg_type.is_empty())
  92
  93     ret = mcgen('''
  94
  95 %(proto)s
  96 {
  97     QDict *qmp;
  98 ''',
  99                 proto=build_event_send_proto(name, arg_type, boxed))
 100
 101     if have_args:
 102         assert arg_type is not None
 103         ret += mcgen('''
 104     QObject *obj;
 105     Visitor *v;
 106 ''')
 107         if not boxed:
 108             ret += gen_param_var(arg_type)
 109
 110     ret += mcgen('''
 111
 112     qmp = qmp_event_build_dict("%(name)s");
 113
 114 ''',
 115                  name=name)
 116
 117     if have_args:
 118         assert arg_type is not None
 119         ret += mcgen('''
 120     v = qobject_output_visitor_new(&obj);
 121 ''')
 122         if not arg_type.is_implicit():
 123             ret += mcgen('''
 124     visit_type_%(c_name)s(v, "%(name)s", &arg, &error_abort);
 125 ''',
 126                          name=name, c_name=arg_type.c_name())
 127         else:
 128             ret += mcgen('''
 129
 130     visit_start_struct(v, "%(name)s", NULL, 0, &error_abort);
 131     visit_type_%(c_name)s_members(v, &param, &error_abort);
 132     visit_check_struct(v, &error_abort);
 133     visit_end_struct(v, NULL);
 134 ''',
 135                          name=name, c_name=arg_type.c_name())
 136         ret += mcgen('''
 137
 138     visit_complete(v, &obj);
 139     qdict_put_obj(qmp, "data", obj);
 140 ''')
 141
 142     ret += mcgen('''
 143     %(event_emit)s(%(c_enum)s, qmp);
 144
 145 ''',
 146                  event_emit=event_emit,
 147                  c_enum=c_enum_const(event_enum_name, name))
 148
 149     if have_args:
 150         ret += mcgen('''
 151     visit_free(v);
 152 ''')
 153     ret += mcgen('''
 154     qobject_unref(qmp);
 155 }
 156 ''')
 157     return ret
 158
 159
 160 class QAPISchemaGenEventVisitor(QAPISchemaModularCVisitor):
 161
 162     def __init__(self, prefix: str):
 163         super().__init__(
 164             prefix, 'qapi-events',
 165             ' * Schema-defined QAPI/QMP events', None, __doc__)
 166         self._event_enum_name = c_name(prefix + 'QAPIEvent', protect=False)
 167         self._event_enum_members: List[QAPISchemaEnumMember] = []
 168         self._event_emit_name = c_name(prefix + 'qapi_event_emit')
 169
 170     def _begin_user_module(self, name: str) -> None:
 171         events = self._module_basename('qapi-events', name)
 172         types = self._module_basename('qapi-types', name)
 173         visit = self._module_basename('qapi-visit', name)
 174         self._genc.add(mcgen('''
 175 #include "qemu/osdep.h"
 176 #include "%(prefix)sqapi-emit-events.h"
 177 #include "%(events)s.h"
 178 #include "%(visit)s.h"
 179 #include "qapi/error.h"
 180 #include "qapi/qmp/qdict.h"
 181 #include "qapi/qobject-output-visitor.h"
 182 #include "qapi/qmp-event.h"
 183
 184 ''',
 185                              events=events, visit=visit,
 186                              prefix=self._prefix))
 187         self._genh.add(mcgen('''
 188 #include "qapi/util.h"
 189 #include "%(types)s.h"
 190 ''',
 191                              types=types))
 192
 193     def visit_end(self) -> None:
 194         self._add_module('./emit', ' * QAPI Events emission')
 195         self._genc.preamble_add(mcgen('''
 196 #include "qemu/osdep.h"
 197 #include "%(prefix)sqapi-emit-events.h"
 198 ''',
 199                                       prefix=self._prefix))
 200         self._genh.preamble_add(mcgen('''
 201 #include "qapi/util.h"
 202 '''))
 203         self._genh.add(gen_enum(self._event_enum_name,
 204                                 self._event_enum_members))
 205         self._genc.add(gen_enum_lookup(self._event_enum_name,
 206                                        self._event_enum_members))
 207         self._genh.add(mcgen('''
 208
 209 void %(event_emit)s(%(event_enum)s event, QDict *qdict);
 210 ''',
 211                              event_emit=self._event_emit_name,
 212                              event_enum=self._event_enum_name))
 213
 214     def visit_event(self,
 215                     name: str,
 216                     info: Optional[QAPISourceInfo],
 217                     ifcond: Sequence[str],
 218                     features: List[QAPISchemaFeature],
 219                     arg_type: Optional[QAPISchemaObjectType],
 220                     boxed: bool) -> None:
 221         with ifcontext(ifcond, self._genh, self._genc):
 222             self._genh.add(gen_event_send_decl(name, arg_type, boxed))
 223             self._genc.add(gen_event_send(name, arg_type, boxed,
 224                                           self._event_enum_name,
 225                                           self._event_emit_name))
 226         # Note: we generate the enum member regardless of @ifcond, to
 227         # keep the enumeration usable in target-independent code.
 228         self._event_enum_members.append(QAPISchemaEnumMember(name, None))
 229
 230
 231 def gen_events(schema: QAPISchema,
 232                output_dir: str,
 233                prefix: str) -> None:
 234     vis = QAPISchemaGenEventVisitor(prefix)
 235     schema.visit(vis)
 236     vis.write(output_dir)