2353.3.8
by John Arbash Meinel
Fix Copyright in lock.py |
1 |
# Copyright (C) 2005, 2006, 2007 Canonical Ltd
|
1887.1.1
by Adeodato Simó
Do not separate paragraphs in the copyright statement with blank lines, |
2 |
#
|
577
by Martin Pool
- merge portable lock module from John |
3 |
# This program is free software; you can redistribute it and/or modify
|
4 |
# it under the terms of the GNU General Public License as published by
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5 |
# the Free Software Foundation; either version 2 of the License, or
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6 |
# (at your option) any later version.
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|
1887.1.1
by Adeodato Simó
Do not separate paragraphs in the copyright statement with blank lines, |
7 |
#
|
577
by Martin Pool
- merge portable lock module from John |
8 |
# This program is distributed in the hope that it will be useful,
|
9 |
# but WITHOUT ANY WARRANTY; without even the implied warranty of
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10 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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11 |
# GNU General Public License for more details.
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|
1887.1.1
by Adeodato Simó
Do not separate paragraphs in the copyright statement with blank lines, |
12 |
#
|
577
by Martin Pool
- merge portable lock module from John |
13 |
# You should have received a copy of the GNU General Public License
|
14 |
# along with this program; if not, write to the Free Software
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|
15 |
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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16 |
||
17 |
||
1553.5.39
by Martin Pool
More lock docs |
18 |
"""Locking using OS file locks or file existence.
|
577
by Martin Pool
- merge portable lock module from John |
19 |
|
1553.5.46
by Martin Pool
doc |
20 |
Note: This method of locking is generally deprecated in favour of LockDir, but
|
21 |
is used to lock local WorkingTrees, and by some old formats. It's accessed
|
|
22 |
through Transport.lock_read(), etc.
|
|
577
by Martin Pool
- merge portable lock module from John |
23 |
|
24 |
This module causes two methods, lock() and unlock() to be defined in
|
|
25 |
any way that works on the current platform.
|
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26 |
||
27 |
It is not specified whether these locks are reentrant (i.e. can be
|
|
28 |
taken repeatedly by a single process) or whether they exclude
|
|
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
29 |
different threads in a single process. That reentrancy is provided by
|
1553.5.39
by Martin Pool
More lock docs |
30 |
LockableFiles.
|
615
by Martin Pool
Major rework of locking code: |
31 |
|
32 |
This defines two classes: ReadLock and WriteLock, which can be
|
|
33 |
implemented in different ways on different platforms. Both have an
|
|
34 |
unlock() method.
|
|
614
by Martin Pool
- unify two defintions of LockError |
35 |
"""
|
577
by Martin Pool
- merge portable lock module from John |
36 |
|
1185.65.29
by Robert Collins
Implement final review suggestions. |
37 |
import errno |
577
by Martin Pool
- merge portable lock module from John |
38 |
|
2353.3.11
by John Arbash Meinel
Code cleanup |
39 |
from bzrlib import ( |
40 |
errors, |
|
41 |
osutils, |
|
42 |
trace, |
|
43 |
)
|
|
1711.8.1
by John Arbash Meinel
Branch.lock_read/lock_write/unlock should handle failures |
44 |
|
577
by Martin Pool
- merge portable lock module from John |
45 |
|
615
by Martin Pool
Major rework of locking code: |
46 |
class _base_Lock(object): |
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
47 |
|
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
48 |
def __init__(self): |
49 |
self.f = None |
|
2353.3.10
by John Arbash Meinel
Cleanup errors, and change ReadOnlyLockError to pass around more details. |
50 |
self.filename = None |
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
51 |
|
615
by Martin Pool
Major rework of locking code: |
52 |
def _open(self, filename, filemode): |
2353.3.11
by John Arbash Meinel
Code cleanup |
53 |
self.filename = osutils.realpath(filename) |
656
by Martin Pool
- create branch lock files if they don't exist |
54 |
try: |
2353.3.10
by John Arbash Meinel
Cleanup errors, and change ReadOnlyLockError to pass around more details. |
55 |
self.f = open(self.filename, filemode) |
656
by Martin Pool
- create branch lock files if they don't exist |
56 |
return self.f |
57 |
except IOError, e: |
|
2353.3.5
by John Arbash Meinel
Fall back on ctypes to get LockFileEx, because msvcrt.locking() |
58 |
if e.errno in (errno.EACCES, errno.EPERM): |
2353.3.10
by John Arbash Meinel
Cleanup errors, and change ReadOnlyLockError to pass around more details. |
59 |
raise errors.ReadOnlyLockError(self.filename, str(e)) |
656
by Martin Pool
- create branch lock files if they don't exist |
60 |
if e.errno != errno.ENOENT: |
61 |
raise
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|
62 |
||
63 |
# maybe this is an old branch (before may 2005)
|
|
2353.3.11
by John Arbash Meinel
Code cleanup |
64 |
trace.mutter("trying to create missing lock %r", self.filename) |
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
65 |
|
2353.3.10
by John Arbash Meinel
Cleanup errors, and change ReadOnlyLockError to pass around more details. |
66 |
self.f = open(self.filename, 'wb+') |
656
by Martin Pool
- create branch lock files if they don't exist |
67 |
return self.f |
68 |
||
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
69 |
def _clear_f(self): |
70 |
"""Clear the self.f attribute cleanly."""
|
|
71 |
if self.f: |
|
72 |
self.f.close() |
|
73 |
self.f = None |
|
74 |
||
615
by Martin Pool
Major rework of locking code: |
75 |
def __del__(self): |
76 |
if self.f: |
|
77 |
from warnings import warn |
|
78 |
warn("lock on %r not released" % self.f) |
|
79 |
self.unlock() |
|
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
80 |
|
615
by Martin Pool
Major rework of locking code: |
81 |
def unlock(self): |
82 |
raise NotImplementedError() |
|
83 |
||
84 |
||
577
by Martin Pool
- merge portable lock module from John |
85 |
try: |
86 |
import fcntl |
|
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
87 |
have_fcntl = True |
88 |
except ImportError: |
|
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
89 |
have_fcntl = False |
90 |
try: |
|
91 |
import win32con, win32file, pywintypes, winerror, msvcrt |
|
92 |
have_pywin32 = True |
|
93 |
except ImportError: |
|
94 |
have_pywin32 = False |
|
95 |
try: |
|
96 |
import ctypes, msvcrt |
|
97 |
have_ctypes = True |
|
98 |
except ImportError: |
|
99 |
have_ctypes = False |
|
100 |
||
101 |
||
102 |
_lock_classes = [] |
|
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
103 |
|
104 |
||
105 |
if have_fcntl: |
|
106 |
LOCK_SH = fcntl.LOCK_SH |
|
107 |
LOCK_NB = fcntl.LOCK_NB |
|
108 |
lock_EX = fcntl.LOCK_EX |
|
109 |
||
615
by Martin Pool
Major rework of locking code: |
110 |
|
111 |
class _fcntl_FileLock(_base_Lock): |
|
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
112 |
|
113 |
def _unlock(self): |
|
1185.9.2
by Harald Meland
Use fcntl.lockf() rather than fcntl.flock() to support NFS file systems. |
114 |
fcntl.lockf(self.f, fcntl.LOCK_UN) |
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
115 |
self._clear_f() |
116 |
||
117 |
||
615
by Martin Pool
Major rework of locking code: |
118 |
class _fcntl_WriteLock(_fcntl_FileLock): |
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
119 |
|
2353.4.1
by John Arbash Meinel
(broken) Change fcntl locks to be properly exclusive within the same process. |
120 |
_open_locks = set() |
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
121 |
|
615
by Martin Pool
Major rework of locking code: |
122 |
def __init__(self, filename): |
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
123 |
super(_fcntl_WriteLock, self).__init__() |
2353.4.2
by John Arbash Meinel
[merge] LockCleanup changes. |
124 |
# Check we can grab a lock before we actually open the file.
|
125 |
self.filename = osutils.realpath(filename) |
|
2353.4.1
by John Arbash Meinel
(broken) Change fcntl locks to be properly exclusive within the same process. |
126 |
if (self.filename in _fcntl_WriteLock._open_locks |
127 |
or self.filename in _fcntl_ReadLock._open_locks): |
|
128 |
self._clear_f() |
|
129 |
raise errors.LockContention(self.filename) |
|
130 |
||
2353.4.2
by John Arbash Meinel
[merge] LockCleanup changes. |
131 |
self._open(self.filename, 'rb+') |
2255.10.2
by John Arbash Meinel
Update to dirstate locking. |
132 |
# reserve a slot for this lock - even if the lockf call fails,
|
133 |
# at thisi point unlock() will be called, because self.f is set.
|
|
134 |
# TODO: make this fully threadsafe, if we decide we care.
|
|
2353.4.1
by John Arbash Meinel
(broken) Change fcntl locks to be properly exclusive within the same process. |
135 |
_fcntl_WriteLock._open_locks.add(self.filename) |
615
by Martin Pool
Major rework of locking code: |
136 |
try: |
2255.10.2
by John Arbash Meinel
Update to dirstate locking. |
137 |
# LOCK_NB will cause IOError to be raised if we can't grab a
|
138 |
# lock right away.
|
|
139 |
fcntl.lockf(self.f, fcntl.LOCK_EX | fcntl.LOCK_NB) |
|
1185.65.29
by Robert Collins
Implement final review suggestions. |
140 |
except IOError, e: |
2255.10.2
by John Arbash Meinel
Update to dirstate locking. |
141 |
if e.errno in (errno.EAGAIN, errno.EACCES): |
142 |
# We couldn't grab the lock
|
|
143 |
self.unlock() |
|
1185.65.29
by Robert Collins
Implement final review suggestions. |
144 |
# we should be more precise about whats a locking
|
145 |
# error and whats a random-other error
|
|
2353.4.1
by John Arbash Meinel
(broken) Change fcntl locks to be properly exclusive within the same process. |
146 |
raise errors.LockError(e) |
615
by Martin Pool
Major rework of locking code: |
147 |
|
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
148 |
def unlock(self): |
2353.4.1
by John Arbash Meinel
(broken) Change fcntl locks to be properly exclusive within the same process. |
149 |
_fcntl_WriteLock._open_locks.remove(self.filename) |
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
150 |
self._unlock() |
151 |
||
152 |
||
615
by Martin Pool
Major rework of locking code: |
153 |
class _fcntl_ReadLock(_fcntl_FileLock): |
1185.65.29
by Robert Collins
Implement final review suggestions. |
154 |
|
2353.4.1
by John Arbash Meinel
(broken) Change fcntl locks to be properly exclusive within the same process. |
155 |
_open_locks = {} |
2353.3.3
by John Arbash Meinel
Define an explicit error when trying to grab a write lock on a readonly file. |
156 |
|
2353.4.3
by John Arbash Meinel
Implement a 'ReadLock.temporary_write_lock()' to upgrade to a write-lock in-process. |
157 |
def __init__(self, filename, _ignore_write_lock=False): |
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
158 |
super(_fcntl_ReadLock, self).__init__() |
2353.4.2
by John Arbash Meinel
[merge] LockCleanup changes. |
159 |
self.filename = osutils.realpath(filename) |
2353.4.3
by John Arbash Meinel
Implement a 'ReadLock.temporary_write_lock()' to upgrade to a write-lock in-process. |
160 |
if not _ignore_write_lock and self.filename in _fcntl_WriteLock._open_locks: |
2353.4.1
by John Arbash Meinel
(broken) Change fcntl locks to be properly exclusive within the same process. |
161 |
raise errors.LockContention(self.filename) |
162 |
_fcntl_ReadLock._open_locks.setdefault(self.filename, 0) |
|
163 |
_fcntl_ReadLock._open_locks[self.filename] += 1 |
|
1185.65.29
by Robert Collins
Implement final review suggestions. |
164 |
self._open(filename, 'rb') |
615
by Martin Pool
Major rework of locking code: |
165 |
try: |
2255.10.2
by John Arbash Meinel
Update to dirstate locking. |
166 |
# LOCK_NB will cause IOError to be raised if we can't grab a
|
167 |
# lock right away.
|
|
168 |
fcntl.lockf(self.f, fcntl.LOCK_SH | fcntl.LOCK_NB) |
|
1185.65.29
by Robert Collins
Implement final review suggestions. |
169 |
except IOError, e: |
170 |
# we should be more precise about whats a locking
|
|
171 |
# error and whats a random-other error
|
|
2353.4.1
by John Arbash Meinel
(broken) Change fcntl locks to be properly exclusive within the same process. |
172 |
raise errors.LockError(e) |
615
by Martin Pool
Major rework of locking code: |
173 |
|
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
174 |
def unlock(self): |
2353.4.1
by John Arbash Meinel
(broken) Change fcntl locks to be properly exclusive within the same process. |
175 |
count = _fcntl_ReadLock._open_locks[self.filename] |
176 |
if count == 1: |
|
177 |
del _fcntl_ReadLock._open_locks[self.filename] |
|
178 |
else: |
|
179 |
_fcntl_ReadLock._open_locks[self.filename] = count - 1 |
|
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
180 |
self._unlock() |
181 |
||
2353.4.3
by John Arbash Meinel
Implement a 'ReadLock.temporary_write_lock()' to upgrade to a write-lock in-process. |
182 |
def temporary_write_lock(self): |
183 |
"""Try to grab a write lock on the file.
|
|
184 |
||
185 |
On platforms that support it, this will upgrade to a write lock
|
|
186 |
without unlocking the file.
|
|
187 |
Otherwise, this will release the read lock, and try to acquire a
|
|
188 |
write lock.
|
|
189 |
||
190 |
:return: A token which can be used to switch back to a read lock.
|
|
191 |
"""
|
|
192 |
assert self.filename not in _fcntl_WriteLock._open_locks |
|
193 |
return _fcntl_TemporaryWriteLock(self) |
|
194 |
||
195 |
||
196 |
class _fcntl_TemporaryWriteLock(_base_Lock): |
|
197 |
"""A token used when grabbing a temporary_write_lock.
|
|
198 |
||
199 |
Call restore_read_lock() when you are done with the write lock.
|
|
200 |
"""
|
|
201 |
||
202 |
def __init__(self, read_lock): |
|
203 |
super(_fcntl_TemporaryWriteLock, self).__init__() |
|
204 |
self._read_lock = read_lock |
|
205 |
self.filename = read_lock.filename |
|
206 |
||
207 |
count = _fcntl_ReadLock._open_locks[self.filename] |
|
208 |
if count > 1: |
|
209 |
# Something else also has a read-lock, so we cannot grab a
|
|
210 |
# write lock.
|
|
211 |
raise errors.LockContention(self.filename) |
|
212 |
||
213 |
assert self.filename not in _fcntl_WriteLock._open_locks |
|
214 |
||
215 |
# See if we can open the file for writing. Another process might
|
|
216 |
# have a read lock. We don't use self._open() because we don't want
|
|
217 |
# to create the file if it exists. That would have already been
|
|
218 |
# done by _fcntl_ReadLock
|
|
219 |
try: |
|
220 |
new_f = open(self.filename, 'rb+') |
|
221 |
except IOError, e: |
|
222 |
if e.errno in (errno.EACCES, errno.EPERM): |
|
223 |
raise errors.ReadOnlyLockError(self.filename, str(e)) |
|
224 |
raise
|
|
225 |
try: |
|
226 |
# LOCK_NB will cause IOError to be raised if we can't grab a
|
|
227 |
# lock right away.
|
|
228 |
fcntl.lockf(new_f, fcntl.LOCK_SH | fcntl.LOCK_NB) |
|
229 |
except IOError, e: |
|
230 |
# TODO: Raise a more specific error based on the type of error
|
|
231 |
raise errors.LockError(e) |
|
232 |
_fcntl_WriteLock._open_locks.add(self.filename) |
|
233 |
||
234 |
self.f = new_f |
|
235 |
||
236 |
def restore_read_lock(self): |
|
237 |
"""Restore the original ReadLock.
|
|
238 |
||
239 |
For fcntl, since we never released the read lock, just release the
|
|
240 |
write lock, and return the original lock.
|
|
241 |
"""
|
|
242 |
fcntl.lockf(self.f, fcntl.LOCK_UN) |
|
243 |
self._clear_f() |
|
244 |
_fcntl_WriteLock._open_locks.remove(self.filename) |
|
245 |
# Avoid reference cycles
|
|
246 |
read_lock = self._read_lock |
|
247 |
self._read_lock = None |
|
248 |
return read_lock |
|
249 |
||
1852.4.3
by Robert Collins
Alter working tree lock and unlock tests to test via the interface rather than via unpublished internals. |
250 |
|
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
251 |
_lock_classes.append(('fcntl', _fcntl_WriteLock, _fcntl_ReadLock)) |
577
by Martin Pool
- merge portable lock module from John |
252 |
|
2353.3.11
by John Arbash Meinel
Code cleanup |
253 |
|
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
254 |
if have_pywin32: |
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
255 |
LOCK_SH = 0 # the default |
256 |
LOCK_EX = win32con.LOCKFILE_EXCLUSIVE_LOCK |
|
257 |
LOCK_NB = win32con.LOCKFILE_FAIL_IMMEDIATELY |
|
258 |
||
259 |
||
260 |
class _w32c_FileLock(_base_Lock): |
|
261 |
||
262 |
def _lock(self, filename, openmode, lockmode): |
|
2353.3.5
by John Arbash Meinel
Fall back on ctypes to get LockFileEx, because msvcrt.locking() |
263 |
self._open(filename, openmode) |
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
264 |
|
2353.3.5
by John Arbash Meinel
Fall back on ctypes to get LockFileEx, because msvcrt.locking() |
265 |
self.hfile = msvcrt.get_osfhandle(self.f.fileno()) |
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
266 |
overlapped = pywintypes.OVERLAPPED() |
267 |
try: |
|
2353.3.5
by John Arbash Meinel
Fall back on ctypes to get LockFileEx, because msvcrt.locking() |
268 |
win32file.LockFileEx(self.hfile, lockmode, 0, 0x7fff0000, |
269 |
overlapped) |
|
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
270 |
except pywintypes.error, e: |
271 |
self._clear_f() |
|
272 |
if e.args[0] in (winerror.ERROR_LOCK_VIOLATION,): |
|
273 |
raise errors.LockContention(filename) |
|
274 |
## import pdb; pdb.set_trace()
|
|
275 |
raise
|
|
276 |
except Exception, e: |
|
277 |
self._clear_f() |
|
2353.3.11
by John Arbash Meinel
Code cleanup |
278 |
raise errors.LockError(e) |
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
279 |
|
280 |
def unlock(self): |
|
2353.3.5
by John Arbash Meinel
Fall back on ctypes to get LockFileEx, because msvcrt.locking() |
281 |
overlapped = pywintypes.OVERLAPPED() |
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
282 |
try: |
283 |
win32file.UnlockFileEx(self.hfile, 0, 0x7fff0000, overlapped) |
|
284 |
self._clear_f() |
|
285 |
except Exception, e: |
|
2353.3.11
by John Arbash Meinel
Code cleanup |
286 |
raise errors.LockError(e) |
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
287 |
|
288 |
||
289 |
class _w32c_ReadLock(_w32c_FileLock): |
|
290 |
def __init__(self, filename): |
|
291 |
super(_w32c_ReadLock, self).__init__() |
|
292 |
self._lock(filename, 'rb', LOCK_SH + LOCK_NB) |
|
293 |
||
2353.3.11
by John Arbash Meinel
Code cleanup |
294 |
|
2353.3.4
by John Arbash Meinel
Clean up the lock.py code to use less indenting, and conform to better coding practise. |
295 |
class _w32c_WriteLock(_w32c_FileLock): |
296 |
def __init__(self, filename): |
|
297 |
super(_w32c_WriteLock, self).__init__() |
|
298 |
self._lock(filename, 'rb+', LOCK_EX + LOCK_NB) |
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299 |
||
2353.3.11
by John Arbash Meinel
Code cleanup |
300 |
|
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
301 |
_lock_classes.append(('pywin32', _w32c_WriteLock, _w32c_ReadLock)) |
302 |
||
2353.3.11
by John Arbash Meinel
Code cleanup |
303 |
|
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
304 |
if have_ctypes: |
2353.3.5
by John Arbash Meinel
Fall back on ctypes to get LockFileEx, because msvcrt.locking() |
305 |
# These constants were copied from the win32con.py module.
|
306 |
LOCKFILE_FAIL_IMMEDIATELY = 1 |
|
307 |
LOCKFILE_EXCLUSIVE_LOCK = 2 |
|
308 |
# Constant taken from winerror.py module
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|
309 |
ERROR_LOCK_VIOLATION = 33 |
|
310 |
||
311 |
LOCK_SH = 0 |
|
312 |
LOCK_EX = LOCKFILE_EXCLUSIVE_LOCK |
|
313 |
LOCK_NB = LOCKFILE_FAIL_IMMEDIATELY |
|
314 |
_LockFileEx = ctypes.windll.kernel32.LockFileEx |
|
315 |
_UnlockFileEx = ctypes.windll.kernel32.UnlockFileEx |
|
316 |
_GetLastError = ctypes.windll.kernel32.GetLastError |
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317 |
||
318 |
### Define the OVERLAPPED structure.
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|
319 |
# http://msdn2.microsoft.com/en-us/library/ms684342.aspx
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320 |
# typedef struct _OVERLAPPED {
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321 |
# ULONG_PTR Internal;
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322 |
# ULONG_PTR InternalHigh;
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|
323 |
# union {
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|
324 |
# struct {
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|
325 |
# DWORD Offset;
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|
326 |
# DWORD OffsetHigh;
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|
327 |
# };
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|
328 |
# PVOID Pointer;
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|
329 |
# };
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|
330 |
# HANDLE hEvent;
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|
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
331 |
# } OVERLAPPED,
|
2353.3.5
by John Arbash Meinel
Fall back on ctypes to get LockFileEx, because msvcrt.locking() |
332 |
|
333 |
class _inner_struct(ctypes.Structure): |
|
334 |
_fields_ = [('Offset', ctypes.c_uint), # DWORD |
|
335 |
('OffsetHigh', ctypes.c_uint), # DWORD |
|
336 |
]
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337 |
||
338 |
class _inner_union(ctypes.Union): |
|
339 |
_fields_ = [('anon_struct', _inner_struct), # struct |
|
340 |
('Pointer', ctypes.c_void_p), # PVOID |
|
341 |
]
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|
342 |
||
343 |
class OVERLAPPED(ctypes.Structure): |
|
344 |
_fields_ = [('Internal', ctypes.c_void_p), # ULONG_PTR |
|
345 |
('InternalHigh', ctypes.c_void_p), # ULONG_PTR |
|
346 |
('_inner_union', _inner_union), |
|
347 |
('hEvent', ctypes.c_void_p), # HANDLE |
|
348 |
]
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349 |
||
350 |
class _ctypes_FileLock(_base_Lock): |
|
351 |
||
352 |
def _lock(self, filename, openmode, lockmode): |
|
353 |
self._open(filename, openmode) |
|
354 |
||
355 |
self.hfile = msvcrt.get_osfhandle(self.f.fileno()) |
|
356 |
overlapped = OVERLAPPED() |
|
357 |
p_overlapped = ctypes.pointer(overlapped) |
|
358 |
result = _LockFileEx(self.hfile, # HANDLE hFile |
|
359 |
lockmode, # DWORD dwFlags |
|
360 |
0, # DWORD dwReserved |
|
361 |
0x7fffffff, # DWORD nNumberOfBytesToLockLow |
|
362 |
0x00000000, # DWORD nNumberOfBytesToLockHigh |
|
363 |
p_overlapped, # lpOverlapped |
|
364 |
)
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|
365 |
if result == 0: |
|
366 |
self._clear_f() |
|
367 |
last_err = _GetLastError() |
|
368 |
if last_err in (ERROR_LOCK_VIOLATION,): |
|
369 |
raise errors.LockContention(filename) |
|
370 |
raise errors.LockError('Unknown locking error: %s' |
|
371 |
% (last_err,)) |
|
372 |
||
373 |
def unlock(self): |
|
374 |
overlapped = OVERLAPPED() |
|
375 |
p_overlapped = ctypes.pointer(overlapped) |
|
376 |
result = _UnlockFileEx(self.hfile, # HANDLE hFile |
|
377 |
0, # DWORD dwReserved |
|
378 |
0x7fffffff, # DWORD nNumberOfBytesToLockLow |
|
379 |
0x00000000, # DWORD nNumberOfBytesToLockHigh |
|
380 |
p_overlapped, # lpOverlapped |
|
381 |
)
|
|
382 |
self._clear_f() |
|
383 |
if result == 0: |
|
384 |
self._clear_f() |
|
385 |
last_err = _GetLastError() |
|
386 |
raise errors.LockError('Unknown unlocking error: %s' |
|
387 |
% (last_err,)) |
|
388 |
||
389 |
||
390 |
class _ctypes_ReadLock(_ctypes_FileLock): |
|
391 |
def __init__(self, filename): |
|
392 |
super(_ctypes_ReadLock, self).__init__() |
|
393 |
self._lock(filename, 'rb', LOCK_SH + LOCK_NB) |
|
394 |
||
2353.3.11
by John Arbash Meinel
Code cleanup |
395 |
|
2353.3.5
by John Arbash Meinel
Fall back on ctypes to get LockFileEx, because msvcrt.locking() |
396 |
class _ctypes_WriteLock(_ctypes_FileLock): |
397 |
def __init__(self, filename): |
|
398 |
super(_ctypes_WriteLock, self).__init__() |
|
399 |
self._lock(filename, 'rb+', LOCK_EX + LOCK_NB) |
|
400 |
||
2353.3.11
by John Arbash Meinel
Code cleanup |
401 |
|
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
402 |
_lock_classes.append(('ctypes', _ctypes_WriteLock, _ctypes_ReadLock)) |
403 |
||
404 |
||
405 |
if len(_lock_classes) == 0: |
|
2353.3.11
by John Arbash Meinel
Code cleanup |
406 |
raise NotImplementedError( |
407 |
"We must have one of fcntl, pywin32, or ctypes available"
|
|
408 |
" to support OS locking."
|
|
409 |
)
|
|
410 |
||
2353.3.9
by John Arbash Meinel
Update the lock code and test code so that if more than one |
411 |
|
412 |
# We default to using the first available lock class.
|
|
413 |
_lock_type, WriteLock, ReadLock = _lock_classes[0] |
|
414 |