scripts/block-coroutine-wrapper.py

   1 #! /usr/bin/env python3
   2 """Generate coroutine wrappers for block subsystem.
   3
   4 The program parses one or several concatenated c files from stdin,
   5 searches for functions with the 'generated_co_wrapper' specifier
   6 and generates corresponding wrappers on stdout.
   7
   8 Usage: block-coroutine-wrapper.py generated-file.c FILE.[ch]...
   9
  10 Copyright (c) 2020 Virtuozzo International GmbH.
  11
  12 This program is free software; you can redistribute it and/or modify
  13 it under the terms of the GNU General Public License as published by
  14 the Free Software Foundation; either version 2 of the License, or
  15 (at your option) any later version.
  16
  17 This program is distributed in the hope that it will be useful,
  18 but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 GNU General Public License for more details.
  21
  22 You should have received a copy of the GNU General Public License
  23 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  24 """
  25
  26 import sys
  27 import re
  28 from typing import Iterator
  29
  30
  31 def gen_header():
  32     copyright = re.sub('^.*Copyright', 'Copyright', __doc__, flags=re.DOTALL)
  33     copyright = re.sub('^(?=.)', ' * ', copyright.strip(), flags=re.MULTILINE)
  34     copyright = re.sub('^$', ' *', copyright, flags=re.MULTILINE)
  35     return f"""\
  36 /*
  37  * File is generated by scripts/block-coroutine-wrapper.py
  38  *
  39 {copyright}
  40  */
  41
  42 #include "qemu/osdep.h"
  43 #include "block/coroutines.h"
  44 #include "block/block-gen.h"
  45 #include "block/block_int.h"\
  46 """
  47
  48
  49 class ParamDecl:
  50     param_re = re.compile(r'(?P<decl>'
  51                           r'(?P<type>.*[ *])'
  52                           r'(?P<name>[a-z][a-z0-9_]*)'
  53                           r')')
  54
  55     def __init__(self, param_decl: str) -> None:
  56         m = self.param_re.match(param_decl.strip())
  57         if m is None:
  58             raise ValueError(f'Wrong parameter declaration: "{param_decl}"')
  59         self.decl = m.group('decl')
  60         self.type = m.group('type')
  61         self.name = m.group('name')
  62
  63
  64 class FuncDecl:
  65     def __init__(self, return_type: str, name: str, args: str) -> None:
  66         self.return_type = return_type.strip()
  67         self.name = name.strip()
  68         self.args = [ParamDecl(arg.strip()) for arg in args.split(',')]
  69
  70     def gen_list(self, format: str) -> str:
  71         return ', '.join(format.format_map(arg.__dict__) for arg in self.args)
  72
  73     def gen_block(self, format: str) -> str:
  74         return '\n'.join(format.format_map(arg.__dict__) for arg in self.args)
  75
  76
  77 # Match wrappers declared with a generated_co_wrapper mark
  78 func_decl_re = re.compile(r'^int\s*generated_co_wrapper\s*'
  79                           r'(?P<wrapper_name>[a-z][a-z0-9_]*)'
  80                           r'\((?P<args>[^)]*)\);$', re.MULTILINE)
  81
  82
  83 def func_decl_iter(text: str) -> Iterator:
  84     for m in func_decl_re.finditer(text):
  85         yield FuncDecl(return_type='int',
  86                        name=m.group('wrapper_name'),
  87                        args=m.group('args'))
  88
  89
  90 def snake_to_camel(func_name: str) -> str:
  91     """
  92     Convert underscore names like 'some_function_name' to camel-case like
  93     'SomeFunctionName'
  94     """
  95     words = func_name.split('_')
  96     words = [w[0].upper() + w[1:] for w in words]
  97     return ''.join(words)
  98
  99
 100 def gen_wrapper(func: FuncDecl) -> str:
 101     assert not '_co_' in func.name
 102     assert func.return_type == 'int'
 103     assert func.args[0].type in ['BlockDriverState *', 'BdrvChild *']
 104
 105     subsystem, subname = func.name.split('_', 1)
 106
 107     name = f'{subsystem}_co_{subname}'
 108     bs = 'bs' if func.args[0].type == 'BlockDriverState *' else 'child->bs'
 109     struct_name = snake_to_camel(name)
 110
 111     return f"""\
 112 /*
 113  * Wrappers for {name}
 114  */
 115
 116 typedef struct {struct_name} {{
 117     BdrvPollCo poll_state;
 118 { func.gen_block('    {decl};') }
 119 }} {struct_name};
 120
 121 static void coroutine_fn {name}_entry(void *opaque)
 122 {{
 123     {struct_name} *s = opaque;
 124
 125     s->poll_state.ret = {name}({ func.gen_list('s->{name}') });
 126     s->poll_state.in_progress = false;
 127
 128     aio_wait_kick();
 129 }}
 130
 131 int {func.name}({ func.gen_list('{decl}') })
 132 {{
 133     if (qemu_in_coroutine()) {{
 134         return {name}({ func.gen_list('{name}') });
 135     }} else {{
 136         {struct_name} s = {{
 137             .poll_state.bs = {bs},
 138             .poll_state.in_progress = true,
 139
 140 { func.gen_block('            .{name} = {name},') }
 141         }};
 142
 143         s.poll_state.co = qemu_coroutine_create({name}_entry, &s);
 144
 145         return bdrv_poll_co(&s.poll_state);
 146     }}
 147 }}"""
 148
 149
 150 def gen_wrappers(input_code: str) -> str:
 151     res = ''
 152     for func in func_decl_iter(input_code):
 153         res += '\n\n\n'
 154         res += gen_wrapper(func)
 155
 156     return res
 157
 158
 159 if __name__ == '__main__':
 160     if len(sys.argv) < 3:
 161         exit(f'Usage: {sys.argv[0]} OUT_FILE.c IN_FILE.[ch]...')
 162
 163     with open(sys.argv[1], 'w', encoding='utf-8') as f_out:
 164         f_out.write(gen_header())
 165         for fname in sys.argv[2:]:
 166             with open(fname, encoding='utf-8') as f_in:
 167                 f_out.write(gen_wrappers(f_in.read()))
 168                 f_out.write('\n')