aboutsummaryrefslogtreecommitdiff
path: root/scripts/block-coroutine-wrapper.py
blob: 0461fd1c459cf2df41db093d5ac01879b0d853d1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
#! /usr/bin/env python3
"""Generate coroutine wrappers for block subsystem.

The program parses one or several concatenated c files from stdin,
searches for functions with the 'generated_co_wrapper' specifier
and generates corresponding wrappers on stdout.

Usage: block-coroutine-wrapper.py generated-file.c FILE.[ch]...

Copyright (c) 2020 Virtuozzo International GmbH.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""

import sys
import re
from typing import Iterator


def gen_header():
    copyright = re.sub('^.*Copyright', 'Copyright', __doc__, flags=re.DOTALL)
    copyright = re.sub('^(?=.)', ' * ', copyright.strip(), flags=re.MULTILINE)
    copyright = re.sub('^$', ' *', copyright, flags=re.MULTILINE)
    return f"""\
/*
 * File is generated by scripts/block-coroutine-wrapper.py
 *
{copyright}
 */

#include "qemu/osdep.h"
#include "block/coroutines.h"
#include "block/block-gen.h"
#include "block/block_int.h"\
"""


class ParamDecl:
    param_re = re.compile(r'(?P<decl>'
                          r'(?P<type>.*[ *])'
                          r'(?P<name>[a-z][a-z0-9_]*)'
                          r')')

    def __init__(self, param_decl: str) -> None:
        m = self.param_re.match(param_decl.strip())
        if m is None:
            raise ValueError(f'Wrong parameter declaration: "{param_decl}"')
        self.decl = m.group('decl')
        self.type = m.group('type')
        self.name = m.group('name')


class FuncDecl:
    def __init__(self, return_type: str, name: str, args: str) -> None:
        self.return_type = return_type.strip()
        self.name = name.strip()
        self.args = [ParamDecl(arg.strip()) for arg in args.split(',')]

    def gen_list(self, format: str) -> str:
        return ', '.join(format.format_map(arg.__dict__) for arg in self.args)

    def gen_block(self, format: str) -> str:
        return '\n'.join(format.format_map(arg.__dict__) for arg in self.args)


# Match wrappers declared with a generated_co_wrapper mark
func_decl_re = re.compile(r'^int\s*generated_co_wrapper\s*'
                          r'(?P<wrapper_name>[a-z][a-z0-9_]*)'
                          r'\((?P<args>[^)]*)\);$', re.MULTILINE)


def func_decl_iter(text: str) -> Iterator:
    for m in func_decl_re.finditer(text):
        yield FuncDecl(return_type='int',
                       name=m.group('wrapper_name'),
                       args=m.group('args'))


def snake_to_camel(func_name: str) -> str:
    """
    Convert underscore names like 'some_function_name' to camel-case like
    'SomeFunctionName'
    """
    words = func_name.split('_')
    words = [w[0].upper() + w[1:] for w in words]
    return ''.join(words)


def gen_wrapper(func: FuncDecl) -> str:
    assert func.name.startswith('bdrv_')
    assert not func.name.startswith('bdrv_co_')
    assert func.return_type == 'int'
    assert func.args[0].type in ['BlockDriverState *', 'BdrvChild *']

    name = 'bdrv_co_' + func.name[5:]
    bs = 'bs' if func.args[0].type == 'BlockDriverState *' else 'child->bs'
    struct_name = snake_to_camel(name)

    return f"""\
/*
 * Wrappers for {name}
 */

typedef struct {struct_name} {{
    BdrvPollCo poll_state;
{ func.gen_block('    {decl};') }
}} {struct_name};

static void coroutine_fn {name}_entry(void *opaque)
{{
    {struct_name} *s = opaque;

    s->poll_state.ret = {name}({ func.gen_list('s->{name}') });
    s->poll_state.in_progress = false;

    aio_wait_kick();
}}

int {func.name}({ func.gen_list('{decl}') })
{{
    if (qemu_in_coroutine()) {{
        return {name}({ func.gen_list('{name}') });
    }} else {{
        {struct_name} s = {{
            .poll_state.bs = {bs},
            .poll_state.in_progress = true,

{ func.gen_block('            .{name} = {name},') }
        }};

        s.poll_state.co = qemu_coroutine_create({name}_entry, &s);

        return bdrv_poll_co(&s.poll_state);
    }}
}}"""


def gen_wrappers(input_code: str) -> str:
    res = ''
    for func in func_decl_iter(input_code):
        res += '\n\n\n'
        res += gen_wrapper(func)

    return res


if __name__ == '__main__':
    if len(sys.argv) < 3:
        exit(f'Usage: {sys.argv[0]} OUT_FILE.c IN_FILE.[ch]...')

    with open(sys.argv[1], 'w', encoding='utf-8') as f_out:
        f_out.write(gen_header())
        for fname in sys.argv[2:]:
            with open(fname, encoding='utf-8') as f_in:
                f_out.write(gen_wrappers(f_in.read()))
                f_out.write('\n')