1
# Copyright (C) 2005, 2006, 2008, 2009 Canonical Ltd
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
5
# the Free Software Foundation; either version 2 of the License, or
6
# (at your option) any later version.
8
# This program is distributed in the hope that it will be useful,
9
# but WITHOUT ANY WARRANTY; without even the implied warranty of
10
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11
# GNU General Public License for more details.
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
15
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17
from cStringIO import StringIO
19
from bzrlib.lazy_import import lazy_import
20
lazy_import(globals(), """
34
from bzrlib.decorators import (
38
from bzrlib.symbol_versioning import (
44
# XXX: The tracking here of lock counts and whether the lock is held is
45
# somewhat redundant with what's done in LockDir; the main difference is that
46
# LockableFiles permits reentrancy.
48
class _LockWarner(object):
49
"""Hold a counter for a lock and warn if GCed while the count is >= 1.
51
This is separate from LockableFiles because putting a __del__ on
52
LockableFiles can result in uncollectable cycles.
55
def __init__(self, repr):
60
if self.lock_count >= 1:
61
# There should have been a try/finally to unlock this.
62
warnings.warn("%r was gc'd while locked" % self.repr)
65
class LockableFiles(object):
66
"""Object representing a set of related files locked within the same scope.
68
These files are used by a WorkingTree, Repository or Branch, and should
69
generally only be touched by that object.
71
LockableFiles also provides some policy on top of Transport for encoding
72
control files as utf-8.
74
LockableFiles manage a lock count and can be locked repeatedly by
75
a single caller. (The underlying lock implementation generally does not
78
Instances of this class are often called control_files.
80
This object builds on top of a Transport, which is used to actually write
81
the files to disk, and an OSLock or LockDir, which controls how access to
82
the files is controlled. The particular type of locking used is set when
83
the object is constructed. In older formats OSLocks are used everywhere.
84
in newer formats a LockDir is used for Repositories and Branches, and
85
OSLocks for the local filesystem.
87
This class is now deprecated; code should move to using the Transport
88
directly for file operations and using the lock or CountedLock for
91
:ivar _lock: The real underlying lock (e.g. a LockDir)
92
:ivar _counted_lock: A lock decorated with a semaphore, so that it
96
# _lock_mode: None, or 'r' or 'w'
98
# _lock_count: If _lock_mode is true, a positive count of the number of
99
# times the lock has been taken *by this process*.
101
def __init__(self, transport, lock_name, lock_class):
102
"""Create a LockableFiles group
104
:param transport: Transport pointing to the directory holding the
105
control files and lock.
106
:param lock_name: Name of the lock guarding these files.
107
:param lock_class: Class of lock strategy to use: typically
108
either LockDir or TransportLock.
110
self._transport = transport
111
self.lock_name = lock_name
112
self._transaction = None
113
self._lock_mode = None
114
self._lock_warner = _LockWarner(repr(self))
116
esc_name = self._escape(lock_name)
117
self._lock = lock_class(transport, esc_name,
118
file_modebits=self._file_mode,
119
dir_modebits=self._dir_mode)
120
self._counted_lock = counted_lock.CountedLock(self._lock)
122
def create_lock(self):
125
This should normally be called only when the LockableFiles directory
126
is first created on disk.
128
self._lock.create(mode=self._dir_mode)
131
return '%s(%r)' % (self.__class__.__name__,
134
return 'LockableFiles(%s, %s)' % (self.lock_name, self._transport.base)
136
def break_lock(self):
137
"""Break the lock of this lockable files group if it is held.
139
The current ui factory will be used to prompt for user conformation.
141
self._lock.break_lock()
143
def _escape(self, file_or_path):
144
"""DEPRECATED: Do not use outside this class"""
145
if not isinstance(file_or_path, basestring):
146
file_or_path = '/'.join(file_or_path)
147
if file_or_path == '':
149
return urlutils.escape(osutils.safe_unicode(file_or_path))
151
def _find_modes(self):
152
"""Determine the appropriate modes for files and directories.
154
:deprecated: Replaced by BzrDir._find_modes.
156
# XXX: The properties created by this can be removed or deprecated
157
# once all the _get_text_store methods etc no longer use them.
160
st = self._transport.stat('.')
161
except errors.TransportNotPossible:
162
self._dir_mode = 0755
163
self._file_mode = 0644
165
# Check the directory mode, but also make sure the created
166
# directories and files are read-write for this user. This is
167
# mostly a workaround for filesystems which lie about being able to
168
# write to a directory (cygwin & win32)
169
self._dir_mode = (st.st_mode & 07777) | 00700
170
# Remove the sticky and execute bits for files
171
self._file_mode = self._dir_mode & ~07111
173
@deprecated_method(deprecated_in((1, 6, 0)))
174
def controlfilename(self, file_or_path):
175
"""Return location relative to branch.
177
:deprecated: Use Transport methods instead.
179
return self._transport.abspath(self._escape(file_or_path))
182
@deprecated_method(deprecated_in((1, 5, 0)))
183
def get(self, relpath):
184
"""Get a file as a bytestream.
186
:deprecated: Use a Transport instead of LockableFiles.
188
relpath = self._escape(relpath)
189
return self._transport.get(relpath)
192
@deprecated_method(deprecated_in((1, 5, 0)))
193
def get_utf8(self, relpath):
194
"""Get a file as a unicode stream.
196
:deprecated: Use a Transport instead of LockableFiles.
198
relpath = self._escape(relpath)
199
# DO NOT introduce an errors=replace here.
200
return codecs.getreader('utf-8')(self._transport.get(relpath))
203
@deprecated_method(deprecated_in((1, 6, 0)))
204
def put(self, path, file):
207
:param path: The path to put the file, relative to the .bzr control
209
:param file: A file-like or string object whose contents should be copied.
211
:deprecated: Use Transport methods instead.
213
self._transport.put_file(self._escape(path), file, mode=self._file_mode)
216
@deprecated_method(deprecated_in((1, 6, 0)))
217
def put_bytes(self, path, a_string):
218
"""Write a string of bytes.
220
:param path: The path to put the bytes, relative to the transport root.
221
:param a_string: A string object, whose exact bytes are to be copied.
223
:deprecated: Use Transport methods instead.
225
self._transport.put_bytes(self._escape(path), a_string,
226
mode=self._file_mode)
229
@deprecated_method(deprecated_in((1, 6, 0)))
230
def put_utf8(self, path, a_string):
231
"""Write a string, encoding as utf-8.
233
:param path: The path to put the string, relative to the transport root.
234
:param string: A string or unicode object whose contents should be copied.
236
:deprecated: Use Transport methods instead.
238
# IterableFile would not be needed if Transport.put took iterables
239
# instead of files. ADHB 2005-12-25
240
# RBC 20060103 surely its not needed anyway, with codecs transcode
242
# JAM 20060103 We definitely don't want encode(..., 'replace')
243
# these are valuable files which should have exact contents.
244
if not isinstance(a_string, basestring):
245
raise errors.BzrBadParameterNotString(a_string)
246
self.put_bytes(path, a_string.encode('utf-8'))
248
def leave_in_place(self):
249
"""Set this LockableFiles to not clear the physical lock on unlock."""
250
self._lock.leave_in_place()
252
def dont_leave_in_place(self):
253
"""Set this LockableFiles to clear the physical lock on unlock."""
254
self._lock.dont_leave_in_place()
256
def lock_write(self, token=None):
257
"""Lock this group of files for writing.
259
:param token: if this is already locked, then lock_write will fail
260
unless the token matches the existing lock.
261
:returns: a token if this instance supports tokens, otherwise None.
262
:raises TokenLockingNotSupported: when a token is given but this
263
instance doesn't support using token locks.
264
:raises MismatchedToken: if the specified token doesn't match the token
265
of the existing lock.
267
A token should be passed in if you know that you have locked the object
268
some other way, and need to synchronise this object's state with that
271
# TODO: Upgrade locking to support using a Transport,
272
# and potentially a remote locking protocol
274
if self._lock_mode != 'w' or not self.get_transaction().writeable():
275
raise errors.ReadOnlyError(self)
276
self._lock.validate_token(token)
277
self._lock_warner.lock_count += 1
278
return self._token_from_lock
280
token_from_lock = self._lock.lock_write(token=token)
281
#traceback.print_stack()
282
self._lock_mode = 'w'
283
self._lock_warner.lock_count = 1
284
self._set_write_transaction()
285
self._token_from_lock = token_from_lock
286
return token_from_lock
290
if self._lock_mode not in ('r', 'w'):
291
raise ValueError("invalid lock mode %r" % (self._lock_mode,))
292
self._lock_warner.lock_count += 1
294
self._lock.lock_read()
295
#traceback.print_stack()
296
self._lock_mode = 'r'
297
self._lock_warner.lock_count = 1
298
self._set_read_transaction()
300
def _set_read_transaction(self):
301
"""Setup a read transaction."""
302
self._set_transaction(transactions.ReadOnlyTransaction())
303
# 5K may be excessive, but hey, its a knob.
304
self.get_transaction().set_cache_size(5000)
306
def _set_write_transaction(self):
307
"""Setup a write transaction."""
308
self._set_transaction(transactions.WriteTransaction())
311
if not self._lock_mode:
312
return lock.cant_unlock_not_held(self)
313
if self._lock_warner.lock_count > 1:
314
self._lock_warner.lock_count -= 1
316
#traceback.print_stack()
317
self._finish_transaction()
321
self._lock_mode = self._lock_warner.lock_count = None
324
def _lock_count(self):
325
return self._lock_warner.lock_count
328
"""Return true if this LockableFiles group is locked"""
329
return self._lock_warner.lock_count >= 1
331
def get_physical_lock_status(self):
332
"""Return physical lock status.
334
Returns true if a lock is held on the transport. If no lock is held, or
335
the underlying locking mechanism does not support querying lock
336
status, false is returned.
339
return self._lock.peek() is not None
340
except NotImplementedError:
343
def get_transaction(self):
344
"""Return the current active transaction.
346
If no transaction is active, this returns a passthrough object
347
for which all data is immediately flushed and no caching happens.
349
if self._transaction is None:
350
return transactions.PassThroughTransaction()
352
return self._transaction
354
def _set_transaction(self, new_transaction):
355
"""Set a new active transaction."""
356
if self._transaction is not None:
357
raise errors.LockError('Branch %s is in a transaction already.' %
359
self._transaction = new_transaction
361
def _finish_transaction(self):
362
"""Exit the current transaction."""
363
if self._transaction is None:
364
raise errors.LockError('Branch %s is not in a transaction' %
366
transaction = self._transaction
367
self._transaction = None
371
class TransportLock(object):
372
"""Locking method which uses transport-dependent locks.
374
On the local filesystem these transform into OS-managed locks.
376
These do not guard against concurrent access via different
379
This is suitable for use only in WorkingTrees (which are at present
382
def __init__(self, transport, escaped_name, file_modebits, dir_modebits):
383
self._transport = transport
384
self._escaped_name = escaped_name
385
self._file_modebits = file_modebits
386
self._dir_modebits = dir_modebits
388
def break_lock(self):
389
raise NotImplementedError(self.break_lock)
391
def leave_in_place(self):
392
raise NotImplementedError(self.leave_in_place)
394
def dont_leave_in_place(self):
395
raise NotImplementedError(self.dont_leave_in_place)
397
def lock_write(self, token=None):
398
if token is not None:
399
raise errors.TokenLockingNotSupported(self)
400
self._lock = self._transport.lock_write(self._escaped_name)
403
self._lock = self._transport.lock_read(self._escaped_name)
410
raise NotImplementedError()
412
def create(self, mode=None):
413
"""Create lock mechanism"""
414
# for old-style locks, create the file now
415
self._transport.put_bytes(self._escaped_name, '',
416
mode=self._file_modebits)
418
def validate_token(self, token):
419
if token is not None:
420
raise errors.TokenLockingNotSupported(self)
added
removed
bzrlib/lockable_files.py
