xref: /openbmc/qemu/scripts/qapi/types.py (revision fb0bc835e56b894cbc7236294921e5393c786ad8) 
1"""
2QAPI types generator
3
4Copyright IBM, Corp. 2011
5Copyright (c) 2013-2018 Red Hat Inc.
6
7Authors:
8 Anthony Liguori <aliguori@us.ibm.com>
9 Michael Roth <mdroth@linux.vnet.ibm.com>
10 Markus Armbruster <armbru@redhat.com>
11
12This work is licensed under the terms of the GNU GPL, version 2.
13# See the COPYING file in the top-level directory.
14"""
15
16from qapi.common import *
17
18
19# variants must be emitted before their container; track what has already
20# been output
21objects_seen = set()
22
23
24def gen_fwd_object_or_array(name):
25    return mcgen('''
26
27typedef struct %(c_name)s %(c_name)s;
28''',
29                 c_name=c_name(name))
30
31
32def gen_array(name, element_type):
33    return mcgen('''
34
35struct %(c_name)s {
36    %(c_name)s *next;
37    %(c_type)s value;
38};
39''',
40                 c_name=c_name(name), c_type=element_type.c_type())
41
42
43def gen_struct_members(members):
44    ret = ''
45    for memb in members:
46        if memb.optional:
47            ret += mcgen('''
48    bool has_%(c_name)s;
49''',
50                         c_name=c_name(memb.name))
51        ret += mcgen('''
52    %(c_type)s %(c_name)s;
53''',
54                     c_type=memb.type.c_type(), c_name=c_name(memb.name))
55    return ret
56
57
58def gen_object(name, base, members, variants):
59    if name in objects_seen:
60        return ''
61    objects_seen.add(name)
62
63    ret = ''
64    if variants:
65        for v in variants.variants:
66            if isinstance(v.type, QAPISchemaObjectType):
67                ret += gen_object(v.type.name, v.type.base,
68                                  v.type.local_members, v.type.variants)
69
70    ret += mcgen('''
71
72struct %(c_name)s {
73''',
74                 c_name=c_name(name))
75
76    if base:
77        if not base.is_implicit():
78            ret += mcgen('''
79    /* Members inherited from %(c_name)s: */
80''',
81                         c_name=base.c_name())
82        ret += gen_struct_members(base.members)
83        if not base.is_implicit():
84            ret += mcgen('''
85    /* Own members: */
86''')
87    ret += gen_struct_members(members)
88
89    if variants:
90        ret += gen_variants(variants)
91
92    # Make sure that all structs have at least one member; this avoids
93    # potential issues with attempting to malloc space for zero-length
94    # structs in C, and also incompatibility with C++ (where an empty
95    # struct is size 1).
96    if (not base or base.is_empty()) and not members and not variants:
97        ret += mcgen('''
98    char qapi_dummy_for_empty_struct;
99''')
100
101    ret += mcgen('''
102};
103''')
104
105    return ret
106
107
108def gen_upcast(name, base):
109    # C makes const-correctness ugly.  We have to cast away const to let
110    # this function work for both const and non-const obj.
111    return mcgen('''
112
113static inline %(base)s *qapi_%(c_name)s_base(const %(c_name)s *obj)
114{
115    return (%(base)s *)obj;
116}
117''',
118                 c_name=c_name(name), base=base.c_name())
119
120
121def gen_variants(variants):
122    ret = mcgen('''
123    union { /* union tag is @%(c_name)s */
124''',
125                c_name=c_name(variants.tag_member.name))
126
127    for var in variants.variants:
128        ret += mcgen('''
129        %(c_type)s %(c_name)s;
130''',
131                     c_type=var.type.c_unboxed_type(),
132                     c_name=c_name(var.name))
133
134    ret += mcgen('''
135    } u;
136''')
137
138    return ret
139
140
141def gen_type_cleanup_decl(name):
142    ret = mcgen('''
143
144void qapi_free_%(c_name)s(%(c_name)s *obj);
145''',
146                c_name=c_name(name))
147    return ret
148
149
150def gen_type_cleanup(name):
151    ret = mcgen('''
152
153void qapi_free_%(c_name)s(%(c_name)s *obj)
154{
155    Visitor *v;
156
157    if (!obj) {
158        return;
159    }
160
161    v = qapi_dealloc_visitor_new();
162    visit_type_%(c_name)s(v, NULL, &obj, NULL);
163    visit_free(v);
164}
165''',
166                c_name=c_name(name))
167    return ret
168
169
170class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
171    def __init__(self, opt_builtins):
172        self._opt_builtins = opt_builtins
173        self.decl = None
174        self.defn = None
175        self._fwdecl = None
176        self._btin = None
177
178    def visit_begin(self, schema):
179        # gen_object() is recursive, ensure it doesn't visit the empty type
180        objects_seen.add(schema.the_empty_object_type.name)
181        self.decl = ''
182        self.defn = ''
183        self._fwdecl = ''
184        self._btin = '\n' + guardstart('QAPI_TYPES_BUILTIN')
185
186    def visit_end(self):
187        self.decl = self._fwdecl + self.decl
188        self._fwdecl = None
189        # To avoid header dependency hell, we always generate
190        # declarations for built-in types in our header files and
191        # simply guard them.  See also opt_builtins (command line
192        # option -b).
193        self._btin += guardend('QAPI_TYPES_BUILTIN')
194        self.decl = self._btin + self.decl
195        self._btin = None
196
197    def _gen_type_cleanup(self, name):
198        self.decl += gen_type_cleanup_decl(name)
199        self.defn += gen_type_cleanup(name)
200
201    def visit_enum_type(self, name, info, values, prefix):
202        # Special case for our lone builtin enum type
203        # TODO use something cleaner than existence of info
204        if not info:
205            self._btin += gen_enum(name, values, prefix)
206            if self._opt_builtins:
207                self.defn += gen_enum_lookup(name, values, prefix)
208        else:
209            self._fwdecl += gen_enum(name, values, prefix)
210            self.defn += gen_enum_lookup(name, values, prefix)
211
212    def visit_array_type(self, name, info, element_type):
213        if isinstance(element_type, QAPISchemaBuiltinType):
214            self._btin += gen_fwd_object_or_array(name)
215            self._btin += gen_array(name, element_type)
216            self._btin += gen_type_cleanup_decl(name)
217            if self._opt_builtins:
218                self.defn += gen_type_cleanup(name)
219        else:
220            self._fwdecl += gen_fwd_object_or_array(name)
221            self.decl += gen_array(name, element_type)
222            self._gen_type_cleanup(name)
223
224    def visit_object_type(self, name, info, base, members, variants):
225        # Nothing to do for the special empty builtin
226        if name == 'q_empty':
227            return
228        self._fwdecl += gen_fwd_object_or_array(name)
229        self.decl += gen_object(name, base, members, variants)
230        if base and not base.is_implicit():
231            self.decl += gen_upcast(name, base)
232        # TODO Worth changing the visitor signature, so we could
233        # directly use rather than repeat type.is_implicit()?
234        if not name.startswith('q_'):
235            # implicit types won't be directly allocated/freed
236            self._gen_type_cleanup(name)
237
238    def visit_alternate_type(self, name, info, variants):
239        self._fwdecl += gen_fwd_object_or_array(name)
240        self.decl += gen_object(name, None, [variants.tag_member], variants)
241        self._gen_type_cleanup(name)
242
243
244def gen_types(schema, output_dir, prefix, opt_builtins):
245    blurb = ' * Schema-defined QAPI types'
246    genc = QAPIGenC(blurb, __doc__)
247    genh = QAPIGenH(blurb, __doc__)
248
249    genc.add(mcgen('''
250#include "qemu/osdep.h"
251#include "qapi/dealloc-visitor.h"
252#include "%(prefix)sqapi-types.h"
253#include "%(prefix)sqapi-visit.h"
254''',
255                   prefix=prefix))
256
257    genh.add(mcgen('''
258#include "qapi/util.h"
259'''))
260
261    vis = QAPISchemaGenTypeVisitor(opt_builtins)
262    schema.visit(vis)
263    genc.add(vis.defn)
264    genh.add(vis.decl)
265    genc.write(output_dir, prefix + 'qapi-types.c')
266    genh.write(output_dir, prefix + 'qapi-types.h')
267