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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
|
# Copyright (C) 2005, 2006 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
from cStringIO import StringIO
import codecs
#import traceback
import bzrlib
from bzrlib.decorators import (needs_read_lock,
needs_write_lock)
import bzrlib.errors as errors
from bzrlib.errors import BzrError
from bzrlib.osutils import file_iterator, safe_unicode
from bzrlib.symbol_versioning import (deprecated_method,
)
from bzrlib.trace import mutter, note
import bzrlib.transactions as transactions
import bzrlib.urlutils as urlutils
# XXX: The tracking here of lock counts and whether the lock is held is
# somewhat redundant with what's done in LockDir; the main difference is that
# LockableFiles permits reentrancy.
class LockableFiles(object):
"""Object representing a set of related files locked within the same scope.
These files are used by a WorkingTree, Repository or Branch, and should
generally only be touched by that object.
LockableFiles also provides some policy on top of Transport for encoding
control files as utf-8.
LockableFiles manage a lock count and can be locked repeatedly by
a single caller. (The underlying lock implementation generally does not
support this.)
Instances of this class are often called control_files.
This object builds on top of a Transport, which is used to actually write
the files to disk, and an OSLock or LockDir, which controls how access to
the files is controlled. The particular type of locking used is set when
the object is constructed. In older formats OSLocks are used everywhere.
in newer formats a LockDir is used for Repositories and Branches, and
OSLocks for the local filesystem.
"""
# _lock_mode: None, or 'r' or 'w'
# _lock_count: If _lock_mode is true, a positive count of the number of
# times the lock has been taken *by this process*.
# If set to False (by a plugin, etc) BzrBranch will not set the
# mode on created files or directories
_set_file_mode = True
_set_dir_mode = True
def __init__(self, transport, lock_name, lock_class):
"""Create a LockableFiles group
:param transport: Transport pointing to the directory holding the
control files and lock.
:param lock_name: Name of the lock guarding these files.
:param lock_class: Class of lock strategy to use: typically
either LockDir or TransportLock.
"""
self._transport = transport
self.lock_name = lock_name
self._transaction = None
self._lock_mode = None
self._lock_count = 0
self._find_modes()
esc_name = self._escape(lock_name)
self._lock = lock_class(transport, esc_name,
file_modebits=self._file_mode,
dir_modebits=self._dir_mode)
def create_lock(self):
"""Create the lock.
This should normally be called only when the LockableFiles directory
is first created on disk.
"""
self._lock.create(mode=self._dir_mode)
def __repr__(self):
return '%s(%r)' % (self.__class__.__name__,
self._transport)
def __str__(self):
return 'LockableFiles(%s, %s)' % (self.lock_name, self._transport.base)
def __del__(self):
if self.is_locked():
# XXX: This should show something every time, and be suitable for
# headless operation and embedding
from warnings import warn
warn("file group %r was not explicitly unlocked" % self)
self._lock.unlock()
def break_lock(self):
"""Break the lock of this lockable files group if it is held.
The current ui factory will be used to prompt for user conformation.
"""
self._lock.break_lock()
def _escape(self, file_or_path):
if not isinstance(file_or_path, basestring):
file_or_path = '/'.join(file_or_path)
if file_or_path == '':
return u''
return urlutils.escape(safe_unicode(file_or_path))
def _find_modes(self):
"""Determine the appropriate modes for files and directories."""
try:
st = self._transport.stat('.')
except errors.TransportNotPossible:
self._dir_mode = 0755
self._file_mode = 0644
else:
self._dir_mode = st.st_mode & 07777
# Remove the sticky and execute bits for files
self._file_mode = self._dir_mode & ~07111
if not self._set_dir_mode:
self._dir_mode = None
if not self._set_file_mode:
self._file_mode = None
def controlfilename(self, file_or_path):
"""Return location relative to branch."""
return self._transport.abspath(self._escape(file_or_path))
@needs_read_lock
def get(self, relpath):
"""Get a file as a bytestream."""
relpath = self._escape(relpath)
return self._transport.get(relpath)
@needs_read_lock
def get_utf8(self, relpath):
"""Get a file as a unicode stream."""
relpath = self._escape(relpath)
# DO NOT introduce an errors=replace here.
return codecs.getreader('utf-8')(self._transport.get(relpath))
@needs_write_lock
def put(self, path, file):
"""Write a file.
:param path: The path to put the file, relative to the .bzr control
directory
:param f: A file-like or string object whose contents should be copied.
"""
self._transport.put_file(self._escape(path), file, mode=self._file_mode)
@needs_write_lock
def put_bytes(self, path, a_string):
"""Write a string of bytes.
:param path: The path to put the bytes, relative to the transport root.
:param string: A string object, whose exact bytes are to be copied.
"""
self._transport.put_bytes(self._escape(path), a_string,
mode=self._file_mode)
@needs_write_lock
def put_utf8(self, path, a_string):
"""Write a string, encoding as utf-8.
:param path: The path to put the string, relative to the transport root.
:param string: A string or unicode object whose contents should be copied.
"""
# IterableFile would not be needed if Transport.put took iterables
# instead of files. ADHB 2005-12-25
# RBC 20060103 surely its not needed anyway, with codecs transcode
# file support ?
# JAM 20060103 We definitely don't want encode(..., 'replace')
# these are valuable files which should have exact contents.
if not isinstance(a_string, basestring):
raise errors.BzrBadParameterNotString(a_string)
self.put_bytes(path, a_string.encode('utf-8'))
def leave_in_place(self):
"""Set this LockableFiles to not clear the physical lock on unlock."""
self._lock.leave_in_place()
def dont_leave_in_place(self):
"""Set this LockableFiles to clear the physical lock on unlock."""
self._lock.dont_leave_in_place()
def lock_write(self, token=None):
"""Lock this group of files for writing.
:param token: if this is already locked, then lock_write will fail
unless the token matches the existing lock.
:returns: a token if this instance supports tokens, otherwise None.
:raises TokenLockingNotSupported: when a token is given but this
instance doesn't support using token locks.
:raises MismatchedToken: if the specified token doesn't match the token
of the existing lock.
A token should be passed in if you know that you have locked the object
some other way, and need to synchronise this object's state with that
fact.
"""
# mutter("lock write: %s (%s)", self, self._lock_count)
# TODO: Upgrade locking to support using a Transport,
# and potentially a remote locking protocol
if self._lock_mode:
if self._lock_mode != 'w' or not self.get_transaction().writeable():
raise errors.ReadOnlyError(self)
self._lock.validate_token(token)
self._lock_count += 1
return self._token_from_lock
else:
token_from_lock = self._lock.lock_write(token=token)
#note('write locking %s', self)
#traceback.print_stack()
self._lock_mode = 'w'
self._lock_count = 1
self._set_transaction(transactions.WriteTransaction())
self._token_from_lock = token_from_lock
return token_from_lock
def lock_read(self):
# mutter("lock read: %s (%s)", self, self._lock_count)
if self._lock_mode:
assert self._lock_mode in ('r', 'w'), \
"invalid lock mode %r" % self._lock_mode
self._lock_count += 1
else:
self._lock.lock_read()
#note('read locking %s', self)
#traceback.print_stack()
self._lock_mode = 'r'
self._lock_count = 1
self._set_transaction(transactions.ReadOnlyTransaction())
# 5K may be excessive, but hey, its a knob.
self.get_transaction().set_cache_size(5000)
def unlock(self):
# mutter("unlock: %s (%s)", self, self._lock_count)
if not self._lock_mode:
raise errors.LockNotHeld(self)
if self._lock_count > 1:
self._lock_count -= 1
else:
#note('unlocking %s', self)
#traceback.print_stack()
self._finish_transaction()
try:
self._lock.unlock()
finally:
self._lock_mode = self._lock_count = None
def is_locked(self):
"""Return true if this LockableFiles group is locked"""
return self._lock_count >= 1
def get_physical_lock_status(self):
"""Return physical lock status.
Returns true if a lock is held on the transport. If no lock is held, or
the underlying locking mechanism does not support querying lock
status, false is returned.
"""
try:
return self._lock.peek() is not None
except NotImplementedError:
return False
def get_transaction(self):
"""Return the current active transaction.
If no transaction is active, this returns a passthrough object
for which all data is immediately flushed and no caching happens.
"""
if self._transaction is None:
return transactions.PassThroughTransaction()
else:
return self._transaction
def _set_transaction(self, new_transaction):
"""Set a new active transaction."""
if self._transaction is not None:
raise errors.LockError('Branch %s is in a transaction already.' %
self)
self._transaction = new_transaction
def _finish_transaction(self):
"""Exit the current transaction."""
if self._transaction is None:
raise errors.LockError('Branch %s is not in a transaction' %
self)
transaction = self._transaction
self._transaction = None
transaction.finish()
class TransportLock(object):
"""Locking method which uses transport-dependent locks.
On the local filesystem these transform into OS-managed locks.
These do not guard against concurrent access via different
transports.
This is suitable for use only in WorkingTrees (which are at present
always local).
"""
def __init__(self, transport, escaped_name, file_modebits, dir_modebits):
self._transport = transport
self._escaped_name = escaped_name
self._file_modebits = file_modebits
self._dir_modebits = dir_modebits
def break_lock(self):
raise NotImplementedError(self.break_lock)
def leave_in_place(self):
raise NotImplementedError(self.leave_in_place)
def dont_leave_in_place(self):
raise NotImplementedError(self.dont_leave_in_place)
def lock_write(self, token=None):
if token is not None:
raise errors.TokenLockingNotSupported(self)
self._lock = self._transport.lock_write(self._escaped_name)
def lock_read(self):
self._lock = self._transport.lock_read(self._escaped_name)
def unlock(self):
self._lock.unlock()
self._lock = None
def peek(self):
raise NotImplementedError()
def create(self, mode=None):
"""Create lock mechanism"""
# for old-style locks, create the file now
self._transport.put_bytes(self._escaped_name, '',
mode=self._file_modebits)
def validate_token(self, token):
if token is not None:
raise errors.TokenLockingNotSupported(self)
|