xref: /qemu/scripts/qapi/gen.py (revision 922d42bb) 
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    List,
21    Optional,
22    Tuple,
23)
24
25from .common import (
26    c_fname,
27    c_name,
28    gen_endif,
29    gen_if,
30    guardend,
31    guardstart,
32    mcgen,
33)
34from .schema import QAPISchemaObjectType, QAPISchemaVisitor
35from .source import QAPISourceInfo
36
37
38class QAPIGen:
39    def __init__(self, fname: Optional[str]):
40        self.fname = fname
41        self._preamble = ''
42        self._body = ''
43
44    def preamble_add(self, text: str) -> None:
45        self._preamble += text
46
47    def add(self, text: str) -> None:
48        self._body += text
49
50    def get_content(self) -> str:
51        return self._top() + self._preamble + self._body + self._bottom()
52
53    def _top(self) -> str:
54        # pylint: disable=no-self-use
55        return ''
56
57    def _bottom(self) -> str:
58        # pylint: disable=no-self-use
59        return ''
60
61    def write(self, output_dir: str) -> None:
62        # Include paths starting with ../ are used to reuse modules of the main
63        # schema in specialised schemas. Don't overwrite the files that are
64        # already generated for the main schema.
65        if self.fname.startswith('../'):
66            return
67        pathname = os.path.join(output_dir, self.fname)
68        odir = os.path.dirname(pathname)
69
70        if odir:
71            os.makedirs(odir, exist_ok=True)
72
73        # use os.open for O_CREAT to create and read a non-existant file
74        fd = os.open(pathname, os.O_RDWR | os.O_CREAT, 0o666)
75        with os.fdopen(fd, 'r+', encoding='utf-8') as fp:
76            text = self.get_content()
77            oldtext = fp.read(len(text) + 1)
78            if text != oldtext:
79                fp.seek(0)
80                fp.truncate(0)
81                fp.write(text)
82
83
84def _wrap_ifcond(ifcond: List[str], before: str, after: str) -> str:
85    if before == after:
86        return after   # suppress empty #if ... #endif
87
88    assert after.startswith(before)
89    out = before
90    added = after[len(before):]
91    if added[0] == '\n':
92        out += '\n'
93        added = added[1:]
94    out += gen_if(ifcond)
95    out += added
96    out += gen_endif(ifcond)
97    return out
98
99
100def build_params(arg_type: Optional[QAPISchemaObjectType],
101                 boxed: bool,
102                 extra: Optional[str] = None) -> str:
103    ret = ''
104    sep = ''
105    if boxed:
106        assert arg_type
107        ret += '%s arg' % arg_type.c_param_type()
108        sep = ', '
109    elif arg_type:
110        assert not arg_type.variants
111        for memb in arg_type.members:
112            ret += sep
113            sep = ', '
114            if memb.optional:
115                ret += 'bool has_%s, ' % c_name(memb.name)
116            ret += '%s %s' % (memb.type.c_param_type(),
117                              c_name(memb.name))
118    if extra:
119        ret += sep + extra
120    return ret if ret else 'void'
121
122
123class QAPIGenCCode(QAPIGen):
124    def __init__(self, fname: Optional[str]):
125        super().__init__(fname)
126        self._start_if: Optional[Tuple[List[str], str, str]] = None
127
128    def start_if(self, ifcond: List[str]) -> None:
129        assert self._start_if is None
130        self._start_if = (ifcond, self._body, self._preamble)
131
132    def end_if(self) -> None:
133        assert self._start_if
134        self._wrap_ifcond()
135        self._start_if = None
136
137    def _wrap_ifcond(self) -> None:
138        self._body = _wrap_ifcond(self._start_if[0],
139                                  self._start_if[1], self._body)
140        self._preamble = _wrap_ifcond(self._start_if[0],
141                                      self._start_if[2], self._preamble)
142
143    def get_content(self) -> str:
144        assert self._start_if is None
145        return super().get_content()
146
147
148class QAPIGenC(QAPIGenCCode):
149    def __init__(self, fname: str, blurb: str, pydoc: str):
150        super().__init__(fname)
151        self._blurb = blurb
152        self._copyright = '\n * '.join(re.findall(r'^Copyright .*', pydoc,
153                                                  re.MULTILINE))
154
155    def _top(self) -> str:
156        return mcgen('''
157/* AUTOMATICALLY GENERATED, DO NOT MODIFY */
158
159/*
160%(blurb)s
161 *
162 * %(copyright)s
163 *
164 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
165 * See the COPYING.LIB file in the top-level directory.
166 */
167
168''',
169                     blurb=self._blurb, copyright=self._copyright)
170
171    def _bottom(self) -> str:
172        return mcgen('''
173
174/* Dummy declaration to prevent empty .o file */
175char qapi_dummy_%(name)s;
176''',
177                     name=c_fname(self.fname))
178
179
180class QAPIGenH(QAPIGenC):
181    def _top(self) -> str:
182        return super()._top() + guardstart(self.fname)
183
184    def _bottom(self) -> str:
185        return guardend(self.fname)
186
187
188@contextmanager
189def ifcontext(ifcond: List[str], *args: QAPIGenCCode) -> Iterator[None]:
190    """
191    A with-statement context manager that wraps with `start_if()` / `end_if()`.
192
193    :param ifcond: A list of conditionals, passed to `start_if()`.
194    :param args: any number of `QAPIGenCCode`.
195
196    Example::
197
198        with ifcontext(ifcond, self._genh, self._genc):
199            modify self._genh and self._genc ...
200
201    Is equivalent to calling::
202
203        self._genh.start_if(ifcond)
204        self._genc.start_if(ifcond)
205        modify self._genh and self._genc ...
206        self._genh.end_if()
207        self._genc.end_if()
208    """
209    for arg in args:
210        arg.start_if(ifcond)
211    yield
212    for arg in args:
213        arg.end_if()
214
215
216class QAPISchemaMonolithicCVisitor(QAPISchemaVisitor):
217    def __init__(self,
218                 prefix: str,
219                 what: str,
220                 blurb: str,
221                 pydoc: str):
222        self._prefix = prefix
223        self._what = what
224        self._genc = QAPIGenC(self._prefix + self._what + '.c',
225                              blurb, pydoc)
226        self._genh = QAPIGenH(self._prefix + self._what + '.h',
227                              blurb, pydoc)
228
229    def write(self, output_dir: str) -> None:
230        self._genc.write(output_dir)
231        self._genh.write(output_dir)
232
233
234class QAPISchemaModularCVisitor(QAPISchemaVisitor):
235    def __init__(self,
236                 prefix: str,
237                 what: str,
238                 user_blurb: str,
239                 builtin_blurb: Optional[str],
240                 pydoc: str):
241        self._prefix = prefix
242        self._what = what
243        self._user_blurb = user_blurb
244        self._builtin_blurb = builtin_blurb
245        self._pydoc = pydoc
246        self._genc: Optional[QAPIGenC] = None
247        self._genh: Optional[QAPIGenH] = None
248        self._module: Dict[Optional[str], Tuple[QAPIGenC, QAPIGenH]] = {}
249        self._main_module: Optional[str] = None
250
251    @staticmethod
252    def _is_user_module(name: Optional[str]) -> bool:
253        return bool(name and not name.startswith('./'))
254
255    @staticmethod
256    def _is_builtin_module(name: Optional[str]) -> bool:
257        return not name
258
259    def _module_dirname(self, name: Optional[str]) -> str:
260        if self._is_user_module(name):
261            return os.path.dirname(name)
262        return ''
263
264    def _module_basename(self, what: str, name: Optional[str]) -> str:
265        ret = '' if self._is_builtin_module(name) else self._prefix
266        if self._is_user_module(name):
267            basename = os.path.basename(name)
268            ret += what
269            if name != self._main_module:
270                ret += '-' + os.path.splitext(basename)[0]
271        else:
272            name = name[2:] if name else 'builtin'
273            ret += re.sub(r'-', '-' + name + '-', what)
274        return ret
275
276    def _module_filename(self, what: str, name: Optional[str]) -> str:
277        return os.path.join(self._module_dirname(name),
278                            self._module_basename(what, name))
279
280    def _add_module(self, name: Optional[str], blurb: str) -> None:
281        basename = self._module_filename(self._what, name)
282        genc = QAPIGenC(basename + '.c', blurb, self._pydoc)
283        genh = QAPIGenH(basename + '.h', blurb, self._pydoc)
284        self._module[name] = (genc, genh)
285        self._genc, self._genh = self._module[name]
286
287    def _add_user_module(self, name: str, blurb: str) -> None:
288        assert self._is_user_module(name)
289        if self._main_module is None:
290            self._main_module = name
291        self._add_module(name, blurb)
292
293    def _add_system_module(self, name: Optional[str], blurb: str) -> None:
294        self._add_module(name and './' + name, blurb)
295
296    def write(self, output_dir: str, opt_builtins: bool = False) -> None:
297        for name in self._module:
298            if self._is_builtin_module(name) and not opt_builtins:
299                continue
300            (genc, genh) = self._module[name]
301            genc.write(output_dir)
302            genh.write(output_dir)
303
304    def _begin_system_module(self, name: None) -> None:
305        pass
306
307    def _begin_user_module(self, name: str) -> None:
308        pass
309
310    def visit_module(self, name: Optional[str]) -> None:
311        if name is None:
312            if self._builtin_blurb:
313                self._add_system_module(None, self._builtin_blurb)
314                self._begin_system_module(name)
315            else:
316                # The built-in module has not been created.  No code may
317                # be generated.
318                self._genc = None
319                self._genh = None
320        else:
321            self._add_user_module(name, self._user_blurb)
322            self._begin_user_module(name)
323
324    def visit_include(self, name: str, info: QAPISourceInfo) -> None:
325        relname = os.path.relpath(self._module_filename(self._what, name),
326                                  os.path.dirname(self._genh.fname))
327        self._genh.preamble_add(mcgen('''
328#include "%(relname)s.h"
329''',
330                                      relname=relname))
331