xref: /openbmc/qemu/scripts/qapi/events.py (revision bf5dcf8f) 
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, Sequence
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    QAPISchemaObjectType,
24)
25from .source import QAPISourceInfo
26from .types import gen_enum, gen_enum_lookup
27
28
29def 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
37def 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
47def 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
80def 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
173class 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
222void %(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
244def 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)
250