xref: /qemu/scripts/qapi/visit.py (revision 9d3524b39e1fe5f3bb7a990ad7841e469e954a3b) 
1#
2# QAPI visitor generator
3#
4# Copyright IBM, Corp. 2011
5# Copyright (C) 2014-2016 Red Hat, Inc.
6#
7# Authors:
8#  Anthony Liguori <aliguori@us.ibm.com>
9#  Michael Roth    <mdroth@linux.vnet.ibm.com>
10#  Markus Armbruster <armbru@redhat.com>
11#
12# This work is licensed under the terms of the GNU GPL, version 2.
13# See the COPYING file in the top-level directory.
14
15from qapi import *
16import re
17
18# visit_type_FOO_implicit() is emitted as needed; track if it has already
19# been output.
20implicit_structs_seen = set()
21
22# visit_type_FOO_fields() is always emitted; track if a forward declaration
23# or implementation has already been output.
24struct_fields_seen = set()
25
26
27def gen_visit_decl(name, scalar=False):
28    c_type = c_name(name) + ' *'
29    if not scalar:
30        c_type += '*'
31    return mcgen('''
32void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_type)sobj, Error **errp);
33''',
34                 c_name=c_name(name), c_type=c_type)
35
36
37def gen_visit_fields_decl(typ):
38    ret = ''
39    if typ.name not in struct_fields_seen:
40        ret += mcgen('''
41
42static void visit_type_%(c_type)s_fields(Visitor *v, %(c_type)s **obj, Error **errp);
43''',
44                     c_type=typ.c_name())
45        struct_fields_seen.add(typ.name)
46    return ret
47
48
49def gen_visit_implicit_struct(typ):
50    if typ in implicit_structs_seen:
51        return ''
52    implicit_structs_seen.add(typ)
53
54    ret = gen_visit_fields_decl(typ)
55
56    ret += mcgen('''
57
58static void visit_type_implicit_%(c_type)s(Visitor *v, %(c_type)s **obj, Error **errp)
59{
60    Error *err = NULL;
61
62    visit_start_implicit_struct(v, (void **)obj, sizeof(%(c_type)s), &err);
63    if (!err) {
64        visit_type_%(c_type)s_fields(v, obj, errp);
65        visit_end_implicit_struct(v);
66    }
67    error_propagate(errp, err);
68}
69''',
70                 c_type=typ.c_name())
71    return ret
72
73
74def gen_visit_struct_fields(name, base, members):
75    ret = ''
76
77    if base:
78        ret += gen_visit_fields_decl(base)
79
80    struct_fields_seen.add(name)
81    ret += mcgen('''
82
83static void visit_type_%(c_name)s_fields(Visitor *v, %(c_name)s **obj, Error **errp)
84{
85    Error *err = NULL;
86
87''',
88                 c_name=c_name(name))
89
90    if base:
91        ret += mcgen('''
92    visit_type_%(c_type)s_fields(v, (%(c_type)s **)obj, &err);
93''',
94                     c_type=base.c_name())
95        ret += gen_err_check()
96
97    ret += gen_visit_fields(members, prefix='(*obj)->')
98
99    # 'goto out' produced for base, and by gen_visit_fields() for each member
100    if base or members:
101        ret += mcgen('''
102
103out:
104''')
105    ret += mcgen('''
106    error_propagate(errp, err);
107}
108''')
109    return ret
110
111
112def gen_visit_struct(name, base, members):
113    ret = gen_visit_struct_fields(name, base, members)
114
115    # FIXME: if *obj is NULL on entry, and visit_start_struct() assigns to
116    # *obj, but then visit_type_FOO_fields() fails, we should clean up *obj
117    # rather than leaving it non-NULL. As currently written, the caller must
118    # call qapi_free_FOO() to avoid a memory leak of the partial FOO.
119    ret += mcgen('''
120
121void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
122{
123    Error *err = NULL;
124
125    visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), &err);
126    if (err) {
127        goto out;
128    }
129    if (!*obj) {
130        goto out_obj;
131    }
132    visit_type_%(c_name)s_fields(v, obj, &err);
133    error_propagate(errp, err);
134    err = NULL;
135out_obj:
136    visit_end_struct(v, &err);
137out:
138    error_propagate(errp, err);
139}
140''',
141                 c_name=c_name(name))
142
143    return ret
144
145
146def gen_visit_list(name, element_type):
147    # FIXME: if *obj is NULL on entry, and the first visit_next_list()
148    # assigns to *obj, while a later one fails, we should clean up *obj
149    # rather than leaving it non-NULL. As currently written, the caller must
150    # call qapi_free_FOOList() to avoid a memory leak of the partial FOOList.
151    return mcgen('''
152
153void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
154{
155    Error *err = NULL;
156    GenericList *i, **prev;
157
158    visit_start_list(v, name, &err);
159    if (err) {
160        goto out;
161    }
162
163    for (prev = (GenericList **)obj;
164         !err && (i = visit_next_list(v, prev)) != NULL;
165         prev = &i) {
166        %(c_name)s *native_i = (%(c_name)s *)i;
167        visit_type_%(c_elt_type)s(v, NULL, &native_i->value, &err);
168    }
169
170    visit_end_list(v);
171out:
172    error_propagate(errp, err);
173}
174''',
175                 c_name=c_name(name), c_elt_type=element_type.c_name())
176
177
178def gen_visit_enum(name):
179    return mcgen('''
180
181void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s *obj, Error **errp)
182{
183    int value = *obj;
184    visit_type_enum(v, name, &value, %(c_name)s_lookup, errp);
185    *obj = value;
186}
187''',
188                 c_name=c_name(name))
189
190
191def gen_visit_alternate(name, variants):
192    promote_int = 'true'
193    for var in variants.variants:
194        if var.type.alternate_qtype() == 'QTYPE_QINT':
195            promote_int = 'false'
196
197    ret = mcgen('''
198
199void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
200{
201    Error *err = NULL;
202
203    visit_start_implicit_struct(v, (void**) obj, sizeof(%(c_name)s), &err);
204    if (err) {
205        goto out;
206    }
207    visit_get_next_type(v, name, &(*obj)->type, %(promote_int)s, &err);
208    if (err) {
209        goto out_obj;
210    }
211    switch ((*obj)->type) {
212''',
213                c_name=c_name(name), promote_int=promote_int)
214
215    for var in variants.variants:
216        ret += mcgen('''
217    case %(case)s:
218        visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, &err);
219        break;
220''',
221                     case=var.type.alternate_qtype(),
222                     c_type=var.type.c_name(),
223                     c_name=c_name(var.name))
224
225    ret += mcgen('''
226    default:
227        error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
228                   "%(name)s");
229    }
230out_obj:
231    visit_end_implicit_struct(v);
232out:
233    error_propagate(errp, err);
234}
235''',
236                 name=name)
237
238    return ret
239
240
241def gen_visit_union(name, base, variants):
242    ret = ''
243
244    if base:
245        ret += gen_visit_fields_decl(base)
246
247    for var in variants.variants:
248        # Ugly special case for simple union TODO get rid of it
249        if not var.simple_union_type():
250            ret += gen_visit_implicit_struct(var.type)
251
252    ret += mcgen('''
253
254void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
255{
256    Error *err = NULL;
257
258    visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), &err);
259    if (err) {
260        goto out;
261    }
262    if (!*obj) {
263        goto out_obj;
264    }
265''',
266                 c_name=c_name(name))
267
268    if base:
269        ret += mcgen('''
270    visit_type_%(c_name)s_fields(v, (%(c_name)s **)obj, &err);
271''',
272                     c_name=base.c_name())
273    else:
274        ret += mcgen('''
275    visit_type_%(c_type)s(v, "%(name)s", &(*obj)->%(c_name)s, &err);
276''',
277                     c_type=variants.tag_member.type.c_name(),
278                     c_name=c_name(variants.tag_member.name),
279                     name=variants.tag_member.name)
280    ret += gen_err_check(label='out_obj')
281    ret += mcgen('''
282    if (!visit_start_union(v, !!(*obj)->u.data, &err) || err) {
283        goto out_obj;
284    }
285    switch ((*obj)->%(c_name)s) {
286''',
287                 c_name=c_name(variants.tag_member.name))
288
289    for var in variants.variants:
290        # TODO ugly special case for simple union
291        simple_union_type = var.simple_union_type()
292        ret += mcgen('''
293    case %(case)s:
294''',
295                     case=c_enum_const(variants.tag_member.type.name,
296                                       var.name,
297                                       variants.tag_member.type.prefix))
298        if simple_union_type:
299            ret += mcgen('''
300        visit_type_%(c_type)s(v, "data", &(*obj)->u.%(c_name)s, &err);
301''',
302                         c_type=simple_union_type.c_name(),
303                         c_name=c_name(var.name))
304        else:
305            ret += mcgen('''
306        visit_type_implicit_%(c_type)s(v, &(*obj)->u.%(c_name)s, &err);
307''',
308                         c_type=var.type.c_name(),
309                         c_name=c_name(var.name))
310        ret += mcgen('''
311        break;
312''')
313
314    ret += mcgen('''
315    default:
316        abort();
317    }
318out_obj:
319    error_propagate(errp, err);
320    err = NULL;
321    visit_end_struct(v, &err);
322out:
323    error_propagate(errp, err);
324}
325''')
326
327    return ret
328
329
330class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
331    def __init__(self):
332        self.decl = None
333        self.defn = None
334        self._btin = None
335
336    def visit_begin(self, schema):
337        self.decl = ''
338        self.defn = ''
339        self._btin = guardstart('QAPI_VISIT_BUILTIN')
340
341    def visit_end(self):
342        # To avoid header dependency hell, we always generate
343        # declarations for built-in types in our header files and
344        # simply guard them.  See also do_builtins (command line
345        # option -b).
346        self._btin += guardend('QAPI_VISIT_BUILTIN')
347        self.decl = self._btin + self.decl
348        self._btin = None
349
350    def visit_needed(self, entity):
351        # Visit everything except implicit objects
352        return not (entity.is_implicit() and
353                    isinstance(entity, QAPISchemaObjectType))
354
355    def visit_enum_type(self, name, info, values, prefix):
356        # Special case for our lone builtin enum type
357        # TODO use something cleaner than existence of info
358        if not info:
359            self._btin += gen_visit_decl(name, scalar=True)
360            if do_builtins:
361                self.defn += gen_visit_enum(name)
362        else:
363            self.decl += gen_visit_decl(name, scalar=True)
364            self.defn += gen_visit_enum(name)
365
366    def visit_array_type(self, name, info, element_type):
367        decl = gen_visit_decl(name)
368        defn = gen_visit_list(name, element_type)
369        if isinstance(element_type, QAPISchemaBuiltinType):
370            self._btin += decl
371            if do_builtins:
372                self.defn += defn
373        else:
374            self.decl += decl
375            self.defn += defn
376
377    def visit_object_type(self, name, info, base, members, variants):
378        self.decl += gen_visit_decl(name)
379        if variants:
380            if members:
381                # Members other than variants.tag_member not implemented
382                assert len(members) == 1
383                assert members[0] == variants.tag_member
384            self.defn += gen_visit_union(name, base, variants)
385        else:
386            self.defn += gen_visit_struct(name, base, members)
387
388    def visit_alternate_type(self, name, info, variants):
389        self.decl += gen_visit_decl(name)
390        self.defn += gen_visit_alternate(name, variants)
391
392# If you link code generated from multiple schemata, you want only one
393# instance of the code for built-in types.  Generate it only when
394# do_builtins, enabled by command line option -b.  See also
395# QAPISchemaGenVisitVisitor.visit_end().
396do_builtins = False
397
398(input_file, output_dir, do_c, do_h, prefix, opts) = \
399    parse_command_line("b", ["builtins"])
400
401for o, a in opts:
402    if o in ("-b", "--builtins"):
403        do_builtins = True
404
405c_comment = '''
406/*
407 * schema-defined QAPI visitor functions
408 *
409 * Copyright IBM, Corp. 2011
410 *
411 * Authors:
412 *  Anthony Liguori   <aliguori@us.ibm.com>
413 *
414 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
415 * See the COPYING.LIB file in the top-level directory.
416 *
417 */
418'''
419h_comment = '''
420/*
421 * schema-defined QAPI visitor functions
422 *
423 * Copyright IBM, Corp. 2011
424 *
425 * Authors:
426 *  Anthony Liguori   <aliguori@us.ibm.com>
427 *
428 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
429 * See the COPYING.LIB file in the top-level directory.
430 *
431 */
432'''
433
434(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
435                            'qapi-visit.c', 'qapi-visit.h',
436                            c_comment, h_comment)
437
438fdef.write(mcgen('''
439#include "qemu/osdep.h"
440#include "qemu-common.h"
441#include "%(prefix)sqapi-visit.h"
442''',
443                 prefix=prefix))
444
445fdecl.write(mcgen('''
446#include "qapi/visitor.h"
447#include "qapi/qmp/qerror.h"
448#include "%(prefix)sqapi-types.h"
449
450''',
451                  prefix=prefix))
452
453schema = QAPISchema(input_file)
454gen = QAPISchemaGenVisitVisitor()
455schema.visit(gen)
456fdef.write(gen.defn)
457fdecl.write(gen.decl)
458
459close_output(fdef, fdecl)
460