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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
from __future__ import annotations
import concurrent.futures
import contextlib
import math
import multiprocessing
import os
import subprocess
import sys
from collections.abc import Callable
from collections.abc import Generator
from collections.abc import Iterable
from collections.abc import MutableMapping
from collections.abc import Sequence
from typing import Any
from typing import TypeVar
from pre_commit import parse_shebang
from pre_commit.util import cmd_output_b
from pre_commit.util import cmd_output_p
TArg = TypeVar('TArg')
TRet = TypeVar('TRet')
def cpu_count() -> int:
try:
# On systems that support it, this will return a more accurate count of
# usable CPUs for the current process, which will take into account
# cgroup limits
return len(os.sched_getaffinity(0))
except AttributeError:
pass
try:
return multiprocessing.cpu_count()
except NotImplementedError:
return 1
def _environ_size(_env: MutableMapping[str, str] | None = None) -> int:
environ = _env if _env is not None else getattr(os, 'environb', os.environ)
size = 8 * len(environ) # number of pointers in `envp`
for k, v in environ.items():
size += len(k) + len(v) + 2 # c strings in `envp`
return size
def _get_platform_max_length() -> int: # pragma: no cover (platform specific)
if os.name == 'posix':
maximum = os.sysconf('SC_ARG_MAX') - 2048 - _environ_size()
maximum = max(min(maximum, 2 ** 17), 2 ** 12)
return maximum
elif os.name == 'nt':
return 2 ** 15 - 2048 # UNICODE_STRING max - headroom
else:
# posix minimum
return 2 ** 12
def _command_length(*cmd: str) -> int:
full_cmd = ' '.join(cmd)
# win32 uses the amount of characters, more details at:
# https://github.com/pre-commit/pre-commit/pull/839
if sys.platform == 'win32':
return len(full_cmd.encode('utf-16le')) // 2
else:
return len(full_cmd.encode(sys.getfilesystemencoding()))
class ArgumentTooLongError(RuntimeError):
pass
def partition(
cmd: Sequence[str],
varargs: Sequence[str],
target_concurrency: int,
_max_length: int | None = None,
) -> tuple[tuple[str, ...], ...]:
_max_length = _max_length or _get_platform_max_length()
# Generally, we try to partition evenly into at least `target_concurrency`
# partitions, but we don't want a bunch of tiny partitions.
max_args = max(4, math.ceil(len(varargs) / target_concurrency))
cmd = tuple(cmd)
ret = []
ret_cmd: list[str] = []
# Reversed so arguments are in order
varargs = list(reversed(varargs))
total_length = _command_length(*cmd) + 1
while varargs:
arg = varargs.pop()
arg_length = _command_length(arg) + 1
if (
total_length + arg_length <= _max_length and
len(ret_cmd) < max_args
):
ret_cmd.append(arg)
total_length += arg_length
elif not ret_cmd:
raise ArgumentTooLongError(arg)
else:
# We've exceeded the length, yield a command
ret.append(cmd + tuple(ret_cmd))
ret_cmd = []
total_length = _command_length(*cmd) + 1
varargs.append(arg)
ret.append(cmd + tuple(ret_cmd))
return tuple(ret)
@contextlib.contextmanager
def _thread_mapper(maxsize: int) -> Generator[
Callable[[Callable[[TArg], TRet], Iterable[TArg]], Iterable[TRet]],
]:
if maxsize == 1:
yield map
else:
with concurrent.futures.ThreadPoolExecutor(maxsize) as ex:
yield ex.map
def xargs(
cmd: tuple[str, ...],
varargs: Sequence[str],
*,
color: bool = False,
target_concurrency: int = 1,
_max_length: int = _get_platform_max_length(),
**kwargs: Any,
) -> tuple[int, bytes]:
"""A simplified implementation of xargs.
color: Make a pty if on a platform that supports it
target_concurrency: Target number of partitions to run concurrently
"""
cmd_fn = cmd_output_p if color else cmd_output_b
retcode = 0
stdout = b''
try:
cmd = parse_shebang.normalize_cmd(cmd)
except parse_shebang.ExecutableNotFoundError as e:
return e.to_output()[:2]
# on windows, batch files have a separate length limit than windows itself
if (
sys.platform == 'win32' and
cmd[0].lower().endswith(('.bat', '.cmd'))
): # pragma: win32 cover
# this is implementation details but the command gets translated into
# full/path/to/cmd.exe /c *cmd
cmd_exe = parse_shebang.find_executable('cmd.exe')
# 1024 is additionally subtracted to give headroom for further
# expansion inside the batch file
_max_length = 8192 - len(cmd_exe) - len(' /c ') - 1024
partitions = partition(cmd, varargs, target_concurrency, _max_length)
def run_cmd_partition(
run_cmd: tuple[str, ...],
) -> tuple[int, bytes, bytes | None]:
return cmd_fn(
*run_cmd, check=False, stderr=subprocess.STDOUT, **kwargs,
)
threads = min(len(partitions), target_concurrency)
with _thread_mapper(threads) as thread_map:
results = thread_map(run_cmd_partition, partitions)
for proc_retcode, proc_out, _ in results:
if abs(proc_retcode) > abs(retcode):
retcode = proc_retcode
stdout += proc_out
return retcode, stdout
|
