xref: /qemu/scripts/qapi/gen.py (revision b3793b8a) 
1# -*- coding: utf-8 -*-
2#
3# QAPI code generation
4#
5# Copyright (c) 2015-2019 Red Hat Inc.
6#
7# Authors:
8#  Markus Armbruster <armbru@redhat.com>
9#  Marc-André Lureau <marcandre.lureau@redhat.com>
10#
11# This work is licensed under the terms of the GNU GPL, version 2.
12# See the COPYING file in the top-level directory.
13
14from contextlib import contextmanager
15import os
16import re
17from typing import (
18    Dict,
19    Iterator,
20    Optional,
21    Sequence,
22    Tuple,
23)
24
25from .common import (
26    c_fname,
27    c_name,
28    guardend,
29    guardstart,
30    mcgen,
31)
32from .schema import (
33    QAPISchemaFeature,
34    QAPISchemaIfCond,
35    QAPISchemaModule,
36    QAPISchemaObjectType,
37    QAPISchemaVisitor,
38)
39from .source import QAPISourceInfo
40
41
42def gen_special_features(features: Sequence[QAPISchemaFeature]) -> str:
43    special_features = [f"1u << QAPI_{feat.name.upper()}"
44                        for feat in features if feat.is_special()]
45    return ' | '.join(special_features) or '0'
46
47
48class QAPIGen:
49    def __init__(self, fname: str):
50        self.fname = fname
51        self._preamble = ''
52        self._body = ''
53
54    def preamble_add(self, text: str) -> None:
55        self._preamble += text
56
57    def add(self, text: str) -> None:
58        self._body += text
59
60    def get_content(self) -> str:
61        return self._top() + self._preamble + self._body + self._bottom()
62
63    def _top(self) -> str:
64        # pylint: disable=no-self-use
65        return ''
66
67    def _bottom(self) -> str:
68        # pylint: disable=no-self-use
69        return ''
70
71    def write(self, output_dir: str) -> None:
72        # Include paths starting with ../ are used to reuse modules of the main
73        # schema in specialised schemas. Don't overwrite the files that are
74        # already generated for the main schema.
75        if self.fname.startswith('../'):
76            return
77        pathname = os.path.join(output_dir, self.fname)
78        odir = os.path.dirname(pathname)
79
80        if odir:
81            os.makedirs(odir, exist_ok=True)
82
83        # use os.open for O_CREAT to create and read a non-existant file
84        fd = os.open(pathname, os.O_RDWR | os.O_CREAT, 0o666)
85        with os.fdopen(fd, 'r+', encoding='utf-8') as fp:
86            text = self.get_content()
87            oldtext = fp.read(len(text) + 1)
88            if text != oldtext:
89                fp.seek(0)
90                fp.truncate(0)
91                fp.write(text)
92
93
94def _wrap_ifcond(ifcond: QAPISchemaIfCond, before: str, after: str) -> str:
95    if before == after:
96        return after   # suppress empty #if ... #endif
97
98    assert after.startswith(before)
99    out = before
100    added = after[len(before):]
101    if added[0] == '\n':
102        out += '\n'
103        added = added[1:]
104    out += ifcond.gen_if()
105    out += added
106    out += ifcond.gen_endif()
107    return out
108
109
110def build_params(arg_type: Optional[QAPISchemaObjectType],
111                 boxed: bool,
112                 extra: Optional[str] = None) -> str:
113    ret = ''
114    sep = ''
115    if boxed:
116        assert arg_type
117        ret += '%s arg' % arg_type.c_param_type()
118        sep = ', '
119    elif arg_type:
120        assert not arg_type.variants
121        for memb in arg_type.members:
122            ret += sep
123            sep = ', '
124            if memb.optional:
125                ret += 'bool has_%s, ' % c_name(memb.name)
126            ret += '%s %s' % (memb.type.c_param_type(),
127                              c_name(memb.name))
128    if extra:
129        ret += sep + extra
130    return ret if ret else 'void'
131
132
133class QAPIGenCCode(QAPIGen):
134    def __init__(self, fname: str):
135        super().__init__(fname)
136        self._start_if: Optional[Tuple[QAPISchemaIfCond, str, str]] = None
137
138    def start_if(self, ifcond: QAPISchemaIfCond) -> None:
139        assert self._start_if is None
140        self._start_if = (ifcond, self._body, self._preamble)
141
142    def end_if(self) -> None:
143        assert self._start_if is not None
144        self._body = _wrap_ifcond(self._start_if[0],
145                                  self._start_if[1], self._body)
146        self._preamble = _wrap_ifcond(self._start_if[0],
147                                      self._start_if[2], self._preamble)
148        self._start_if = None
149
150    def get_content(self) -> str:
151        assert self._start_if is None
152        return super().get_content()
153
154
155class QAPIGenC(QAPIGenCCode):
156    def __init__(self, fname: str, blurb: str, pydoc: str):
157        super().__init__(fname)
158        self._blurb = blurb
159        self._copyright = '\n * '.join(re.findall(r'^Copyright .*', pydoc,
160                                                  re.MULTILINE))
161
162    def _top(self) -> str:
163        return mcgen('''
164/* AUTOMATICALLY GENERATED, DO NOT MODIFY */
165
166/*
167%(blurb)s
168 *
169 * %(copyright)s
170 *
171 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
172 * See the COPYING.LIB file in the top-level directory.
173 */
174
175''',
176                     blurb=self._blurb, copyright=self._copyright)
177
178    def _bottom(self) -> str:
179        return mcgen('''
180
181/* Dummy declaration to prevent empty .o file */
182char qapi_dummy_%(name)s;
183''',
184                     name=c_fname(self.fname))
185
186
187class QAPIGenH(QAPIGenC):
188    def _top(self) -> str:
189        return super()._top() + guardstart(self.fname)
190
191    def _bottom(self) -> str:
192        return guardend(self.fname)
193
194
195@contextmanager
196def ifcontext(ifcond: QAPISchemaIfCond, *args: QAPIGenCCode) -> Iterator[None]:
197    """
198    A with-statement context manager that wraps with `start_if()` / `end_if()`.
199
200    :param ifcond: A sequence of conditionals, passed to `start_if()`.
201    :param args: any number of `QAPIGenCCode`.
202
203    Example::
204
205        with ifcontext(ifcond, self._genh, self._genc):
206            modify self._genh and self._genc ...
207
208    Is equivalent to calling::
209
210        self._genh.start_if(ifcond)
211        self._genc.start_if(ifcond)
212        modify self._genh and self._genc ...
213        self._genh.end_if()
214        self._genc.end_if()
215    """
216    for arg in args:
217        arg.start_if(ifcond)
218    yield
219    for arg in args:
220        arg.end_if()
221
222
223class QAPISchemaMonolithicCVisitor(QAPISchemaVisitor):
224    def __init__(self,
225                 prefix: str,
226                 what: str,
227                 blurb: str,
228                 pydoc: str):
229        self._prefix = prefix
230        self._what = what
231        self._genc = QAPIGenC(self._prefix + self._what + '.c',
232                              blurb, pydoc)
233        self._genh = QAPIGenH(self._prefix + self._what + '.h',
234                              blurb, pydoc)
235
236    def write(self, output_dir: str) -> None:
237        self._genc.write(output_dir)
238        self._genh.write(output_dir)
239
240
241class QAPISchemaModularCVisitor(QAPISchemaVisitor):
242    def __init__(self,
243                 prefix: str,
244                 what: str,
245                 user_blurb: str,
246                 builtin_blurb: Optional[str],
247                 pydoc: str):
248        self._prefix = prefix
249        self._what = what
250        self._user_blurb = user_blurb
251        self._builtin_blurb = builtin_blurb
252        self._pydoc = pydoc
253        self._current_module: Optional[str] = None
254        self._module: Dict[str, Tuple[QAPIGenC, QAPIGenH]] = {}
255        self._main_module: Optional[str] = None
256
257    @property
258    def _genc(self) -> QAPIGenC:
259        assert self._current_module is not None
260        return self._module[self._current_module][0]
261
262    @property
263    def _genh(self) -> QAPIGenH:
264        assert self._current_module is not None
265        return self._module[self._current_module][1]
266
267    @staticmethod
268    def _module_dirname(name: str) -> str:
269        if QAPISchemaModule.is_user_module(name):
270            return os.path.dirname(name)
271        return ''
272
273    def _module_basename(self, what: str, name: str) -> str:
274        ret = '' if QAPISchemaModule.is_builtin_module(name) else self._prefix
275        if QAPISchemaModule.is_user_module(name):
276            basename = os.path.basename(name)
277            ret += what
278            if name != self._main_module:
279                ret += '-' + os.path.splitext(basename)[0]
280        else:
281            assert QAPISchemaModule.is_system_module(name)
282            ret += re.sub(r'-', '-' + name[2:] + '-', what)
283        return ret
284
285    def _module_filename(self, what: str, name: str) -> str:
286        return os.path.join(self._module_dirname(name),
287                            self._module_basename(what, name))
288
289    def _add_module(self, name: str, blurb: str) -> None:
290        if QAPISchemaModule.is_user_module(name):
291            if self._main_module is None:
292                self._main_module = name
293        basename = self._module_filename(self._what, name)
294        genc = QAPIGenC(basename + '.c', blurb, self._pydoc)
295        genh = QAPIGenH(basename + '.h', blurb, self._pydoc)
296        self._module[name] = (genc, genh)
297        self._current_module = name
298
299    @contextmanager
300    def _temp_module(self, name: str) -> Iterator[None]:
301        old_module = self._current_module
302        self._current_module = name
303        yield
304        self._current_module = old_module
305
306    def write(self, output_dir: str, opt_builtins: bool = False) -> None:
307        for name, (genc, genh) in self._module.items():
308            if QAPISchemaModule.is_builtin_module(name) and not opt_builtins:
309                continue
310            genc.write(output_dir)
311            genh.write(output_dir)
312
313    def _begin_builtin_module(self) -> None:
314        pass
315
316    def _begin_user_module(self, name: str) -> None:
317        pass
318
319    def visit_module(self, name: str) -> None:
320        if QAPISchemaModule.is_builtin_module(name):
321            if self._builtin_blurb:
322                self._add_module(name, self._builtin_blurb)
323                self._begin_builtin_module()
324            else:
325                # The built-in module has not been created.  No code may
326                # be generated.
327                self._current_module = None
328        else:
329            assert QAPISchemaModule.is_user_module(name)
330            self._add_module(name, self._user_blurb)
331            self._begin_user_module(name)
332
333    def visit_include(self, name: str, info: Optional[QAPISourceInfo]) -> None:
334        relname = os.path.relpath(self._module_filename(self._what, name),
335                                  os.path.dirname(self._genh.fname))
336        self._genh.preamble_add(mcgen('''
337#include "%(relname)s.h"
338''',
339                                      relname=relname))
340