1
# Copyright (C) 2005, 2006 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17
from cStringIO import StringIO
22
from bzrlib.decorators import *
23
import bzrlib.errors as errors
24
from bzrlib.errors import BzrError
25
from bzrlib.osutils import file_iterator, safe_unicode
26
from bzrlib.symbol_versioning import *
27
from bzrlib.trace import mutter, note
28
import bzrlib.transactions as transactions
30
# XXX: The tracking here of lock counts and whether the lock is held is
31
# somewhat redundant with what's done in LockDir; the main difference is that
32
# LockableFiles permits reentrancy.
34
class LockableFiles(object):
35
"""Object representing a set of related files locked within the same scope.
37
These files are used by a WorkingTree, Repository or Branch, and should
38
generally only be touched by that object.
40
LockableFiles also provides some policy on top of Transport for encoding
41
control files as utf-8.
43
LockableFiles manage a lock count and can be locked repeatedly by
44
a single caller. (The underlying lock implementation generally does not
47
Instances of this class are often called control_files.
49
This object builds on top of a Transport, which is used to actually write
50
the files to disk, and an OSLock or LockDir, which controls how access to
51
the files is controlled. The particular type of locking used is set when
52
the object is constructed. In older formats OSLocks are used everywhere.
53
in newer formats a LockDir is used for Repositories and Branches, and
54
OSLocks for the local filesystem.
57
# _lock_mode: None, or 'r' or 'w'
59
# _lock_count: If _lock_mode is true, a positive count of the number of
60
# times the lock has been taken *by this process*.
62
# If set to False (by a plugin, etc) BzrBranch will not set the
63
# mode on created files or directories
67
def __init__(self, transport, lock_name, lock_class):
68
"""Create a LockableFiles group
70
:param transport: Transport pointing to the directory holding the
71
control files and lock.
72
:param lock_name: Name of the lock guarding these files.
73
:param lock_class: Class of lock strategy to use: typically
74
either LockDir or TransportLock.
76
self._transport = transport
77
self.lock_name = lock_name
78
self._transaction = None
79
self._lock_mode = None
82
esc_name = self._escape(lock_name)
83
self._lock = lock_class(transport, esc_name,
84
file_modebits=self._file_mode,
85
dir_modebits=self._dir_mode)
87
def create_lock(self):
90
This should normally be called only when the LockableFiles directory
91
is first created on disk.
93
self._lock.create(mode=self._dir_mode)
96
return '%s(%r)' % (self.__class__.__name__,
99
return 'LockableFiles(%s, %s)' % (self.lock_name, self._transport.base)
103
# XXX: This should show something every time, and be suitable for
104
# headless operation and embedding
105
from warnings import warn
106
warn("file group %r was not explicitly unlocked" % self)
109
def break_lock(self):
110
"""Break the lock of this lockable files group if it is held.
112
The current ui factory will be used to prompt for user conformation.
114
self._lock.break_lock()
116
def _escape(self, file_or_path):
117
if not isinstance(file_or_path, basestring):
118
file_or_path = '/'.join(file_or_path)
119
if file_or_path == '':
121
return bzrlib.transport.urlescape(safe_unicode(file_or_path))
123
def _find_modes(self):
124
"""Determine the appropriate modes for files and directories."""
126
st = self._transport.stat('.')
127
except errors.TransportNotPossible:
128
self._dir_mode = 0755
129
self._file_mode = 0644
131
self._dir_mode = st.st_mode & 07777
132
# Remove the sticky and execute bits for files
133
self._file_mode = self._dir_mode & ~07111
134
if not self._set_dir_mode:
135
self._dir_mode = None
136
if not self._set_file_mode:
137
self._file_mode = None
139
def controlfilename(self, file_or_path):
140
"""Return location relative to branch."""
141
return self._transport.abspath(self._escape(file_or_path))
143
@deprecated_method(zero_eight)
144
def controlfile(self, file_or_path, mode='r'):
145
"""Open a control file for this branch.
147
There are two classes of file in a lockable directory: text
148
and binary. binary files are untranslated byte streams. Text
149
control files are stored with Unix newlines and in UTF-8, even
150
if the platform or locale defaults are different.
152
Such files are not openable in write mode : they are managed via
153
put and put_utf8 which atomically replace old versions using
157
relpath = self._escape(file_or_path)
158
# TODO: codecs.open() buffers linewise, so it was overloaded with
159
# a much larger buffer, do we need to do the same for getreader/getwriter?
161
return self.get(relpath)
163
raise BzrError("Branch.controlfile(mode='wb') is not supported, use put[_utf8]")
165
return self.get_utf8(relpath)
167
raise BzrError("Branch.controlfile(mode='w') is not supported, use put[_utf8]")
169
raise BzrError("invalid controlfile mode %r" % mode)
172
def get(self, relpath):
173
"""Get a file as a bytestream."""
174
relpath = self._escape(relpath)
175
return self._transport.get(relpath)
178
def get_utf8(self, relpath):
179
"""Get a file as a unicode stream."""
180
relpath = self._escape(relpath)
181
# DO NOT introduce an errors=replace here.
182
return codecs.getreader('utf-8')(self._transport.get(relpath))
185
def put(self, path, file):
188
:param path: The path to put the file, relative to the .bzr control
190
:param f: A file-like or string object whose contents should be copied.
192
self._transport.put(self._escape(path), file, mode=self._file_mode)
195
def put_utf8(self, path, a_string):
196
"""Write a string, encoding as utf-8.
198
:param path: The path to put the string, relative to the transport root.
199
:param string: A file-like or string object whose contents should be copied.
201
# IterableFile would not be needed if Transport.put took iterables
202
# instead of files. ADHB 2005-12-25
203
# RBC 20060103 surely its not needed anyway, with codecs transcode
205
# JAM 20060103 We definitely don't want encode(..., 'replace')
206
# these are valuable files which should have exact contents.
207
if not isinstance(a_string, basestring):
208
raise errors.BzrBadParameterNotString(a_string)
209
self.put(path, StringIO(a_string.encode('utf-8')))
211
def lock_write(self):
212
# mutter("lock write: %s (%s)", self, self._lock_count)
213
# TODO: Upgrade locking to support using a Transport,
214
# and potentially a remote locking protocol
216
if self._lock_mode != 'w' or not self.get_transaction().writeable():
217
raise errors.ReadOnlyError(self)
218
self._lock_count += 1
220
self._lock.lock_write()
221
#note('write locking %s', self)
222
#traceback.print_stack()
223
self._lock_mode = 'w'
225
self._set_transaction(transactions.WriteTransaction())
228
# mutter("lock read: %s (%s)", self, self._lock_count)
230
assert self._lock_mode in ('r', 'w'), \
231
"invalid lock mode %r" % self._lock_mode
232
self._lock_count += 1
234
self._lock.lock_read()
235
#note('read locking %s', self)
236
#traceback.print_stack()
237
self._lock_mode = 'r'
239
self._set_transaction(transactions.ReadOnlyTransaction())
240
# 5K may be excessive, but hey, its a knob.
241
self.get_transaction().set_cache_size(5000)
244
# mutter("unlock: %s (%s)", self, self._lock_count)
245
if not self._lock_mode:
246
raise errors.LockNotHeld(self)
247
if self._lock_count > 1:
248
self._lock_count -= 1
250
#note('unlocking %s', self)
251
#traceback.print_stack()
252
self._finish_transaction()
256
self._lock_mode = self._lock_count = None
259
"""Return true if this LockableFiles group is locked"""
260
return self._lock_count >= 1
262
def get_physical_lock_status(self):
263
"""Return physical lock status.
265
Returns true if a lock is held on the transport. If no lock is held, or
266
the underlying locking mechanism does not support querying lock
267
status, false is returned.
270
return self._lock.peek() is not None
271
except NotImplementedError:
274
def get_transaction(self):
275
"""Return the current active transaction.
277
If no transaction is active, this returns a passthrough object
278
for which all data is immediately flushed and no caching happens.
280
if self._transaction is None:
281
return transactions.PassThroughTransaction()
283
return self._transaction
285
def _set_transaction(self, new_transaction):
286
"""Set a new active transaction."""
287
if self._transaction is not None:
288
raise errors.LockError('Branch %s is in a transaction already.' %
290
self._transaction = new_transaction
292
def _finish_transaction(self):
293
"""Exit the current transaction."""
294
if self._transaction is None:
295
raise errors.LockError('Branch %s is not in a transaction' %
297
transaction = self._transaction
298
self._transaction = None
302
class TransportLock(object):
303
"""Locking method which uses transport-dependent locks.
305
On the local filesystem these transform into OS-managed locks.
307
These do not guard against concurrent access via different
310
This is suitable for use only in WorkingTrees (which are at present
313
def __init__(self, transport, escaped_name, file_modebits, dir_modebits):
314
self._transport = transport
315
self._escaped_name = escaped_name
316
self._file_modebits = file_modebits
317
self._dir_modebits = dir_modebits
319
def break_lock(self):
320
raise NotImplementedError(self.break_lock)
322
def lock_write(self):
323
self._lock = self._transport.lock_write(self._escaped_name)
326
self._lock = self._transport.lock_read(self._escaped_name)
333
raise NotImplementedError()
335
def create(self, mode=None):
336
"""Create lock mechanism"""
337
# for old-style locks, create the file now
338
self._transport.put(self._escaped_name, StringIO(),
339
mode=self._file_modebits)
added
removed
bzrlib/lockable_files.py
