xref: /qemu/scripts/qapi/visit.py (revision e98859a9b96d71dea8f9af43325edd43c7effe66) 
1#
2# QAPI visitor generator
3#
4# Copyright IBM, Corp. 2011
5# Copyright (C) 2014-2015 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
18implicit_structs_seen = set()
19struct_fields_seen = set()
20
21
22def gen_visit_implicit_struct(typ):
23    if typ in implicit_structs_seen:
24        return ''
25    implicit_structs_seen.add(typ)
26
27    ret = ''
28    if typ.name not in struct_fields_seen:
29        # Need a forward declaration
30        ret += mcgen('''
31
32static void visit_type_%(c_type)s_fields(Visitor *m, %(c_type)s **obj, Error **errp);
33''',
34                     c_type=typ.c_name())
35
36    ret += mcgen('''
37
38static void visit_type_implicit_%(c_type)s(Visitor *m, %(c_type)s **obj, Error **errp)
39{
40    Error *err = NULL;
41
42    visit_start_implicit_struct(m, (void **)obj, sizeof(%(c_type)s), &err);
43    if (!err) {
44        visit_type_%(c_type)s_fields(m, obj, errp);
45        visit_end_implicit_struct(m, &err);
46    }
47    error_propagate(errp, err);
48}
49''',
50                 c_type=typ.c_name())
51    return ret
52
53
54def gen_visit_struct_fields(name, base, members):
55    struct_fields_seen.add(name)
56
57    ret = ''
58
59    if base:
60        ret += gen_visit_implicit_struct(base)
61
62    ret += mcgen('''
63
64static void visit_type_%(c_name)s_fields(Visitor *m, %(c_name)s **obj, Error **errp)
65{
66    Error *err = NULL;
67
68''',
69                 c_name=c_name(name))
70    push_indent()
71
72    if base:
73        ret += mcgen('''
74visit_type_implicit_%(c_type)s(m, &(*obj)->%(c_name)s, &err);
75if (err) {
76    goto out;
77}
78''',
79                     c_type=base.c_name(), c_name=c_name('base'))
80
81    for memb in members:
82        if memb.optional:
83            ret += mcgen('''
84visit_optional(m, &(*obj)->has_%(c_name)s, "%(name)s", &err);
85if (!err && (*obj)->has_%(c_name)s) {
86''',
87                         c_name=c_name(memb.name), name=memb.name)
88            push_indent()
89
90        ret += mcgen('''
91visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "%(name)s", &err);
92''',
93                     c_type=memb.type.c_name(), c_name=c_name(memb.name),
94                     name=memb.name)
95
96        if memb.optional:
97            pop_indent()
98            ret += mcgen('''
99}
100''')
101        ret += mcgen('''
102if (err) {
103    goto out;
104}
105''')
106
107    pop_indent()
108    if re.search('^ *goto out;', ret, re.MULTILINE):
109        ret += mcgen('''
110
111out:
112''')
113    ret += mcgen('''
114    error_propagate(errp, err);
115}
116''')
117    return ret
118
119
120def gen_visit_struct_body(name):
121    # FIXME: if *obj is NULL on entry, and visit_start_struct() assigns to
122    # *obj, but then visit_type_FOO_fields() fails, we should clean up *obj
123    # rather than leaving it non-NULL. As currently written, the caller must
124    # call qapi_free_FOO() to avoid a memory leak of the partial FOO.
125    ret = mcgen('''
126    Error *err = NULL;
127
128    visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(c_name)s), &err);
129    if (!err) {
130        if (*obj) {
131            visit_type_%(c_name)s_fields(m, obj, errp);
132        }
133        visit_end_struct(m, &err);
134    }
135    error_propagate(errp, err);
136''',
137                name=name, c_name=c_name(name))
138    return ret
139
140
141def gen_visit_struct(name, base, members):
142    ret = gen_visit_struct_fields(name, base, members)
143    ret += mcgen('''
144
145void visit_type_%(c_name)s(Visitor *m, %(c_name)s **obj, const char *name, Error **errp)
146{
147''',
148                 c_name=c_name(name))
149
150    ret += gen_visit_struct_body(name)
151
152    ret += mcgen('''
153}
154''')
155    return ret
156
157
158def gen_visit_list(name, element_type):
159    return mcgen('''
160
161void visit_type_%(c_name)s(Visitor *m, %(c_name)s **obj, const char *name, Error **errp)
162{
163    Error *err = NULL;
164    GenericList *i, **prev;
165
166    visit_start_list(m, name, &err);
167    if (err) {
168        goto out;
169    }
170
171    for (prev = (GenericList **)obj;
172         !err && (i = visit_next_list(m, prev, &err)) != NULL;
173         prev = &i) {
174        %(c_name)s *native_i = (%(c_name)s *)i;
175        visit_type_%(c_elt_type)s(m, &native_i->value, NULL, &err);
176    }
177
178    error_propagate(errp, err);
179    err = NULL;
180    visit_end_list(m, &err);
181out:
182    error_propagate(errp, err);
183}
184''',
185                 c_name=c_name(name), c_elt_type=element_type.c_name())
186
187
188def gen_visit_enum(name):
189    return mcgen('''
190
191void visit_type_%(c_name)s(Visitor *m, %(c_name)s *obj, const char *name, Error **errp)
192{
193    visit_type_enum(m, (int *)obj, %(c_name)s_lookup, "%(name)s", name, errp);
194}
195''',
196                 c_name=c_name(name), name=name)
197
198
199def gen_visit_alternate(name, variants):
200    ret = mcgen('''
201
202void visit_type_%(c_name)s(Visitor *m, %(c_name)s **obj, const char *name, Error **errp)
203{
204    Error *err = NULL;
205
206    visit_start_implicit_struct(m, (void**) obj, sizeof(%(c_name)s), &err);
207    if (err) {
208        goto out;
209    }
210    visit_get_next_type(m, (int*) &(*obj)->kind, %(c_name)s_qtypes, name, &err);
211    if (err) {
212        goto out_end;
213    }
214    switch ((*obj)->kind) {
215''',
216                c_name=c_name(name))
217
218    for var in variants.variants:
219        ret += mcgen('''
220    case %(case)s:
221        visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, name, &err);
222        break;
223''',
224                     case=c_enum_const(variants.tag_member.type.name,
225                                       var.name),
226                     c_type=var.type.c_name(),
227                     c_name=c_name(var.name))
228
229    ret += mcgen('''
230    default:
231        abort();
232    }
233out_end:
234    error_propagate(errp, err);
235    err = NULL;
236    visit_end_implicit_struct(m, &err);
237out:
238    error_propagate(errp, err);
239}
240''')
241
242    return ret
243
244
245def gen_visit_union(name, base, variants):
246    ret = ''
247
248    if base:
249        members = [m for m in base.members if m != variants.tag_member]
250        ret += gen_visit_struct_fields(name, None, members)
251
252    for var in variants.variants:
253        # Ugly special case for simple union TODO get rid of it
254        if not var.simple_union_type():
255            ret += gen_visit_implicit_struct(var.type)
256
257    ret += mcgen('''
258
259void visit_type_%(c_name)s(Visitor *m, %(c_name)s **obj, const char *name, Error **errp)
260{
261    Error *err = NULL;
262
263    visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(c_name)s), &err);
264    if (err) {
265        goto out;
266    }
267    if (*obj) {
268''',
269                 c_name=c_name(name), name=name)
270
271    if base:
272        ret += mcgen('''
273        visit_type_%(c_name)s_fields(m, obj, &err);
274        if (err) {
275            goto out_obj;
276        }
277''',
278                     c_name=c_name(name))
279
280    tag_key = variants.tag_member.name
281    if not variants.tag_name:
282        # we pointlessly use a different key for simple unions
283        tag_key = 'type'
284    ret += mcgen('''
285        visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "%(name)s", &err);
286        if (err) {
287            goto out_obj;
288        }
289        if (!visit_start_union(m, !!(*obj)->data, &err) || err) {
290            goto out_obj;
291        }
292        switch ((*obj)->%(c_name)s) {
293''',
294                 c_type=variants.tag_member.type.c_name(),
295                 # TODO ugly special case for simple union
296                 # Use same tag name in C as on the wire to get rid of
297                 # it, then: c_name=c_name(variants.tag_member.name)
298                 c_name=c_name(variants.tag_name or 'kind'),
299                 name=tag_key)
300
301    for var in variants.variants:
302        # TODO ugly special case for simple union
303        simple_union_type = var.simple_union_type()
304        ret += mcgen('''
305        case %(case)s:
306''',
307                     case=c_enum_const(variants.tag_member.type.name,
308                                       var.name))
309        if simple_union_type:
310            ret += mcgen('''
311            visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "data", &err);
312''',
313                         c_type=simple_union_type.c_name(),
314                         c_name=c_name(var.name))
315        else:
316            ret += mcgen('''
317            visit_type_implicit_%(c_type)s(m, &(*obj)->%(c_name)s, &err);
318''',
319                         c_type=var.type.c_name(),
320                         c_name=c_name(var.name))
321        ret += mcgen('''
322            break;
323''')
324
325    ret += mcgen('''
326        default:
327            abort();
328        }
329out_obj:
330        error_propagate(errp, err);
331        err = NULL;
332        visit_end_union(m, !!(*obj)->data, &err);
333        error_propagate(errp, err);
334        err = NULL;
335    }
336    visit_end_struct(m, &err);
337out:
338    error_propagate(errp, err);
339}
340''')
341
342    return ret
343
344
345def gen_visit_decl(name, scalar=False):
346    c_type = c_name(name) + ' *'
347    if not scalar:
348        c_type += '*'
349    return mcgen('''
350void visit_type_%(c_name)s(Visitor *m, %(c_type)sobj, const char *name, Error **errp);
351''',
352                 c_name=c_name(name), c_type=c_type)
353
354
355class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
356    def __init__(self):
357        self.decl = None
358        self.defn = None
359        self._btin = None
360
361    def visit_begin(self, schema):
362        self.decl = ''
363        self.defn = ''
364        self._btin = guardstart('QAPI_VISIT_BUILTIN')
365
366    def visit_end(self):
367        # To avoid header dependency hell, we always generate
368        # declarations for built-in types in our header files and
369        # simply guard them.  See also do_builtins (command line
370        # option -b).
371        self._btin += guardend('QAPI_VISIT_BUILTIN')
372        self.decl = self._btin + self.decl
373        self._btin = None
374
375    def visit_enum_type(self, name, info, values, prefix):
376        self.decl += gen_visit_decl(name, scalar=True)
377        self.defn += gen_visit_enum(name)
378
379    def visit_array_type(self, name, info, element_type):
380        decl = gen_visit_decl(name)
381        defn = gen_visit_list(name, element_type)
382        if isinstance(element_type, QAPISchemaBuiltinType):
383            self._btin += decl
384            if do_builtins:
385                self.defn += defn
386        else:
387            self.decl += decl
388            self.defn += defn
389
390    def visit_object_type(self, name, info, base, members, variants):
391        if info:
392            self.decl += gen_visit_decl(name)
393            if variants:
394                assert not members      # not implemented
395                self.defn += gen_visit_union(name, base, variants)
396            else:
397                self.defn += gen_visit_struct(name, base, members)
398
399    def visit_alternate_type(self, name, info, variants):
400        self.decl += gen_visit_decl(name)
401        self.defn += gen_visit_alternate(name, variants)
402
403# If you link code generated from multiple schemata, you want only one
404# instance of the code for built-in types.  Generate it only when
405# do_builtins, enabled by command line option -b.  See also
406# QAPISchemaGenVisitVisitor.visit_end().
407do_builtins = False
408
409(input_file, output_dir, do_c, do_h, prefix, opts) = \
410    parse_command_line("b", ["builtins"])
411
412for o, a in opts:
413    if o in ("-b", "--builtins"):
414        do_builtins = True
415
416c_comment = '''
417/*
418 * schema-defined QAPI visitor functions
419 *
420 * Copyright IBM, Corp. 2011
421 *
422 * Authors:
423 *  Anthony Liguori   <aliguori@us.ibm.com>
424 *
425 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
426 * See the COPYING.LIB file in the top-level directory.
427 *
428 */
429'''
430h_comment = '''
431/*
432 * schema-defined QAPI visitor functions
433 *
434 * Copyright IBM, Corp. 2011
435 *
436 * Authors:
437 *  Anthony Liguori   <aliguori@us.ibm.com>
438 *
439 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
440 * See the COPYING.LIB file in the top-level directory.
441 *
442 */
443'''
444
445(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
446                            'qapi-visit.c', 'qapi-visit.h',
447                            c_comment, h_comment)
448
449fdef.write(mcgen('''
450#include "qemu-common.h"
451#include "%(prefix)sqapi-visit.h"
452''',
453                 prefix=prefix))
454
455fdecl.write(mcgen('''
456#include "qapi/visitor.h"
457#include "%(prefix)sqapi-types.h"
458
459''',
460                  prefix=prefix))
461
462schema = QAPISchema(input_file)
463gen = QAPISchemaGenVisitVisitor()
464schema.visit(gen)
465fdef.write(gen.defn)
466fdecl.write(gen.decl)
467
468close_output(fdef, fdecl)
469