Repository navigation
Expand file tree
/
Copy pathfilelock.py
More file actions
135 lines (107 loc) · 3.64 KB
/
Copy pathfilelock.py
File metadata and controls
135 lines (107 loc) · 3.64 KB
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
# The MIT License
#
# Copyright (c) 2015-2021 Sebastian Ramacher
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
from typing import Optional, Type, IO
from ._typing_compat import Literal
from types import TracebackType
has_fcntl = True
try:
import fcntl
import errno
except ImportError:
has_fcntl = False
has_msvcrt = True
try:
import msvcrt
import os
except ImportError:
has_msvcrt = False
class BaseLock:
"""Base class for file locking"""
def __init__(self) -> None:
self.locked = False
def acquire(self) -> None:
pass
def release(self) -> None:
pass
def __enter__(self) -> "BaseLock":
self.acquire()
return self
def __exit__(
self,
exc_type: Optional[Type[BaseException]],
exc: Optional[BaseException],
exc_tb: Optional[TracebackType],
) -> Literal[False]:
if self.locked:
self.release()
return False
def __del__(self) -> None:
if self.locked:
self.release()
class UnixFileLock(BaseLock):
"""Simple file locking for Unix using fcntl"""
def __init__(self, fileobj, mode: int = 0) -> None:
super().__init__()
self.fileobj = fileobj
self.mode = mode | fcntl.LOCK_EX
def acquire(self) -> None:
try:
fcntl.flock(self.fileobj, self.mode)
self.locked = True
except OSError as e:
if e.errno != errno.ENOLCK:
raise e
def release(self) -> None:
self.locked = False
fcntl.flock(self.fileobj, fcntl.LOCK_UN)
class WindowsFileLock(BaseLock):
"""Simple file locking for Windows using msvcrt"""
def __init__(self, filename: str) -> None:
super().__init__()
self.filename = f"{filename}.lock"
self.fileobj = -1
def acquire(self) -> None:
# create a lock file and lock it
self.fileobj = os.open(
self.filename, os.O_RDWR | os.O_CREAT | os.O_TRUNC
)
msvcrt.locking(self.fileobj, msvcrt.LK_NBLCK, 1)
self.locked = True
def release(self) -> None:
self.locked = False
# unlock lock file and remove it
msvcrt.locking(self.fileobj, msvcrt.LK_UNLCK, 1)
os.close(self.fileobj)
self.fileobj = -1
try:
os.remove(self.filename)
except OSError:
pass
def FileLock(
fileobj: IO, mode: int = 0, filename: Optional[str] = None
) -> BaseLock:
if has_fcntl:
return UnixFileLock(fileobj, mode)
elif has_msvcrt and filename is not None:
return WindowsFileLock(filename)
return BaseLock()
# vim: sw=4 ts=4 sts=4 ai et