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