xref: /qemu/scripts/qapi/events.py (revision c3bef3b4) 
1"""
2QAPI event generator
3
4Copyright (c) 2014 Wenchao Xia
5Copyright (c) 2015-2018 Red Hat Inc.
6
7Authors:
8 Wenchao Xia <wenchaoqemu@gmail.com>
9 Markus Armbruster <armbru@redhat.com>
10
11This work is licensed under the terms of the GNU GPL, version 2.
12See the COPYING file in the top-level directory.
13"""
14
15from typing import List, Optional
16
17from .common import c_enum_const, c_name, mcgen
18from .gen import QAPISchemaModularCVisitor, build_params, ifcontext
19from .schema import (
20    QAPISchema,
21    QAPISchemaEnumMember,
22    QAPISchemaFeature,
23    QAPISchemaIfCond,
24    QAPISchemaObjectType,
25)
26from .source import QAPISourceInfo
27from .types import gen_enum, gen_enum_lookup
28
29
30def 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
38def 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
48def 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.need_has():
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
81def 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
176class 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                             events=events, visit=visit,
201                             prefix=self._prefix))
202        self._genh.add(mcgen('''
203#include "qapi/util.h"
204#include "%(types)s.h"
205''',
206                             types=types))
207
208    def visit_end(self) -> None:
209        self._add_module('./emit', ' * QAPI Events emission')
210        self._genc.preamble_add(mcgen('''
211#include "qemu/osdep.h"
212#include "%(prefix)sqapi-emit-events.h"
213''',
214                                      prefix=self._prefix))
215        self._genh.preamble_add(mcgen('''
216#include "qapi/util.h"
217'''))
218        self._genh.add(gen_enum(self._event_enum_name,
219                                self._event_enum_members))
220        self._genc.add(gen_enum_lookup(self._event_enum_name,
221                                       self._event_enum_members))
222        self._genh.add(mcgen('''
223
224void %(event_emit)s(%(event_enum)s event, QDict *qdict);
225''',
226                             event_emit=self._event_emit_name,
227                             event_enum=self._event_enum_name))
228
229    def visit_event(self,
230                    name: str,
231                    info: Optional[QAPISourceInfo],
232                    ifcond: QAPISchemaIfCond,
233                    features: List[QAPISchemaFeature],
234                    arg_type: Optional[QAPISchemaObjectType],
235                    boxed: bool) -> None:
236        with ifcontext(ifcond, self._genh, self._genc):
237            self._genh.add(gen_event_send_decl(name, arg_type, boxed))
238            self._genc.add(gen_event_send(name, arg_type, features, boxed,
239                                          self._event_enum_name,
240                                          self._event_emit_name))
241        # Note: we generate the enum member regardless of @ifcond, to
242        # keep the enumeration usable in target-independent code.
243        self._event_enum_members.append(QAPISchemaEnumMember(name, None))
244
245
246def gen_events(schema: QAPISchema,
247               output_dir: str,
248               prefix: str) -> None:
249    vis = QAPISchemaGenEventVisitor(prefix)
250    schema.visit(vis)
251    vis.write(output_dir)
252