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
|
from abc import ABC
from abc import abstractmethod
import errno
import os
class _InterProcessReaderWriterLockMechanism(ABC):
@staticmethod
@abstractmethod
def trylock(lockfile, exclusive):
...
@staticmethod
@abstractmethod
def unlock(lockfile):
...
@staticmethod
@abstractmethod
def get_handle(path):
...
@staticmethod
@abstractmethod
def close_handle(lockfile):
...
class _InterProcessMechanism(ABC):
@staticmethod
@abstractmethod
def trylock(lockfile):
...
@staticmethod
@abstractmethod
def unlock(lockfile):
...
class _WindowsInterProcessMechanism(_InterProcessMechanism):
"""Interprocess lock implementation that works on windows systems."""
@staticmethod
def trylock(lockfile):
fileno = lockfile.fileno()
msvcrt.locking(fileno, msvcrt.LK_NBLCK, 1)
@staticmethod
def unlock(lockfile):
fileno = lockfile.fileno()
msvcrt.locking(fileno, msvcrt.LK_UNLCK, 1)
class _FcntlInterProcessMechanism(_InterProcessMechanism):
"""Interprocess lock implementation that works on posix systems."""
@staticmethod
def trylock(lockfile):
fcntl.lockf(lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
@staticmethod
def unlock(lockfile):
fcntl.lockf(lockfile, fcntl.LOCK_UN)
class _WindowsInterProcessReaderWriterLockMechanism(_InterProcessReaderWriterLockMechanism):
"""Interprocess readers writer lock implementation that works on windows
systems."""
@staticmethod
def trylock(lockfile, exclusive):
if exclusive:
flags = win32con.LOCKFILE_FAIL_IMMEDIATELY | win32con.LOCKFILE_EXCLUSIVE_LOCK
else:
flags = win32con.LOCKFILE_FAIL_IMMEDIATELY
handle = msvcrt.get_osfhandle(lockfile.fileno())
ok = win32file.LockFileEx(handle, flags, 0, 1, 0, win32file.pointer(pywintypes.OVERLAPPED()))
if ok:
return True
else:
last_error = win32file.GetLastError()
if last_error == win32file.ERROR_LOCK_VIOLATION:
return False
else:
raise OSError(last_error)
@staticmethod
def unlock(lockfile):
handle = msvcrt.get_osfhandle(lockfile.fileno())
ok = win32file.UnlockFileEx(handle, 0, 1, 0, win32file.pointer(pywintypes.OVERLAPPED()))
if not ok:
raise OSError(win32file.GetLastError())
@staticmethod
def get_handle(path):
return open(path, 'a+')
@staticmethod
def close_handle(lockfile):
lockfile.close()
class _FcntlInterProcessReaderWriterLockMechanism(_InterProcessReaderWriterLockMechanism):
"""Interprocess readers writer lock implementation that works on posix
systems."""
@staticmethod
def trylock(lockfile, exclusive):
if exclusive:
flags = fcntl.LOCK_EX | fcntl.LOCK_NB
else:
flags = fcntl.LOCK_SH | fcntl.LOCK_NB
try:
fcntl.lockf(lockfile, flags)
return True
except (IOError, OSError) as e:
if e.errno in (errno.EACCES, errno.EAGAIN):
return False
else:
raise e
@staticmethod
def unlock(lockfile):
fcntl.lockf(lockfile, fcntl.LOCK_UN)
@staticmethod
def get_handle(path):
return open(path, 'a+')
@staticmethod
def close_handle(lockfile):
lockfile.close()
if os.name == 'nt':
import msvcrt
import fasteners.pywin32.pywintypes as pywintypes
import fasteners.pywin32.win32con as win32con
import fasteners.pywin32.win32file as win32file
_interprocess_reader_writer_mechanism = _WindowsInterProcessReaderWriterLockMechanism()
_interprocess_mechanism = _WindowsInterProcessMechanism()
else:
import fcntl
_interprocess_reader_writer_mechanism = _FcntlInterProcessReaderWriterLockMechanism()
_interprocess_mechanism = _FcntlInterProcessMechanism()
|
