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
29
import bzrlib.urlutils as urlutils
32
# XXX: The tracking here of lock counts and whether the lock is held is
33
# somewhat redundant with what's done in LockDir; the main difference is that
34
# LockableFiles permits reentrancy.
36
class LockableFiles(object):
37
"""Object representing a set of related files locked within the same scope.
39
These files are used by a WorkingTree, Repository or Branch, and should
40
generally only be touched by that object.
42
LockableFiles also provides some policy on top of Transport for encoding
43
control files as utf-8.
45
LockableFiles manage a lock count and can be locked repeatedly by
46
a single caller. (The underlying lock implementation generally does not
49
Instances of this class are often called control_files.
51
This object builds on top of a Transport, which is used to actually write
52
the files to disk, and an OSLock or LockDir, which controls how access to
53
the files is controlled. The particular type of locking used is set when
54
the object is constructed. In older formats OSLocks are used everywhere.
55
in newer formats a LockDir is used for Repositories and Branches, and
56
OSLocks for the local filesystem.
59
# _lock_mode: None, or 'r' or 'w'
61
# _lock_count: If _lock_mode is true, a positive count of the number of
62
# times the lock has been taken *by this process*.
64
# If set to False (by a plugin, etc) BzrBranch will not set the
65
# mode on created files or directories
69
def __init__(self, transport, lock_name, lock_class):
70
"""Create a LockableFiles group
72
:param transport: Transport pointing to the directory holding the
73
control files and lock.
74
:param lock_name: Name of the lock guarding these files.
75
:param lock_class: Class of lock strategy to use: typically
76
either LockDir or TransportLock.
79
self._transport = transport
80
self.lock_name = lock_name
81
self._transaction = None
82
# Need to happen before _find_modes in case it throws an exception
83
# __del__ expects _lock_count to be available
84
self._lock_mode = None
87
esc_name = self._escape(lock_name)
88
self._lock = lock_class(transport, esc_name,
89
file_modebits=self._file_mode,
90
dir_modebits=self._dir_mode)
92
def create_lock(self):
95
This should normally be called only when the LockableFiles directory
96
is first created on disk.
98
self._lock.create(mode=self._dir_mode)
101
return '%s(%r)' % (self.__class__.__name__,
104
return 'LockableFiles(%s, %s)' % (self.lock_name, self._transport.base)
108
# XXX: This should show something every time, and be suitable for
109
# headless operation and embedding
110
from warnings import warn
111
warn("file group %r was not explicitly unlocked" % self)
114
def break_lock(self):
115
"""Break the lock of this lockable files group if it is held.
117
The current ui factory will be used to prompt for user conformation.
119
self._lock.break_lock()
121
def _escape(self, file_or_path):
122
if not isinstance(file_or_path, basestring):
123
file_or_path = '/'.join(file_or_path)
124
if file_or_path == '':
126
return urlutils.escape(safe_unicode(file_or_path))
128
def _find_modes(self):
129
"""Determine the appropriate modes for files and directories."""
131
st = self._transport.stat('.')
132
except errors.TransportNotPossible:
133
self._dir_mode = 0755
134
self._file_mode = 0644
136
self._dir_mode = st.st_mode & 07777
137
# Remove the sticky and execute bits for files
138
self._file_mode = self._dir_mode & ~07111
139
if not self._set_dir_mode:
140
self._dir_mode = None
141
if not self._set_file_mode:
142
self._file_mode = None
144
def controlfilename(self, file_or_path):
145
"""Return location relative to branch."""
146
return self._transport.abspath(self._escape(file_or_path))
148
@deprecated_method(zero_eight)
149
def controlfile(self, file_or_path, mode='r'):
150
"""Open a control file for this branch.
152
There are two classes of file in a lockable directory: text
153
and binary. binary files are untranslated byte streams. Text
154
control files are stored with Unix newlines and in UTF-8, even
155
if the platform or locale defaults are different.
157
Such files are not openable in write mode : they are managed via
158
put and put_utf8 which atomically replace old versions using
162
relpath = self._escape(file_or_path)
163
# TODO: codecs.open() buffers linewise, so it was overloaded with
164
# a much larger buffer, do we need to do the same for getreader/getwriter?
166
return self.get(relpath)
168
raise BzrError("Branch.controlfile(mode='wb') is not supported, use put[_utf8]")
170
return self.get_utf8(relpath)
172
raise BzrError("Branch.controlfile(mode='w') is not supported, use put[_utf8]")
174
raise BzrError("invalid controlfile mode %r" % mode)
177
def get(self, relpath):
178
"""Get a file as a bytestream."""
179
relpath = self._escape(relpath)
180
return self._transport.get(relpath)
183
def get_utf8(self, relpath):
184
"""Get a file as a unicode stream."""
185
relpath = self._escape(relpath)
186
# DO NOT introduce an errors=replace here.
187
return codecs.getreader('utf-8')(self._transport.get(relpath))
190
def put(self, path, file):
193
:param path: The path to put the file, relative to the .bzr control
195
:param f: A file-like or string object whose contents should be copied.
197
self._transport.put(self._escape(path), file, mode=self._file_mode)
200
def put_utf8(self, path, a_string):
201
"""Write a string, encoding as utf-8.
203
:param path: The path to put the string, relative to the transport root.
204
:param string: A file-like or string object whose contents should be copied.
206
# IterableFile would not be needed if Transport.put took iterables
207
# instead of files. ADHB 2005-12-25
208
# RBC 20060103 surely its not needed anyway, with codecs transcode
210
# JAM 20060103 We definitely don't want encode(..., 'replace')
211
# these are valuable files which should have exact contents.
212
if not isinstance(a_string, basestring):
213
raise errors.BzrBadParameterNotString(a_string)
214
self.put(path, StringIO(a_string.encode('utf-8')))
216
def lock_write(self):
217
# mutter("lock write: %s (%s)", self, self._lock_count)
218
# TODO: Upgrade locking to support using a Transport,
219
# and potentially a remote locking protocol
221
if self._lock_mode != 'w' or not self.get_transaction().writeable():
222
raise errors.ReadOnlyError(self)
223
self._lock_count += 1
225
self._lock.lock_write()
226
#note('write locking %s', self)
227
#traceback.print_stack()
228
self._lock_mode = 'w'
230
self._set_transaction(transactions.WriteTransaction())
233
# mutter("lock read: %s (%s)", self, self._lock_count)
235
assert self._lock_mode in ('r', 'w'), \
236
"invalid lock mode %r" % self._lock_mode
237
self._lock_count += 1
239
self._lock.lock_read()
240
#note('read locking %s', self)
241
#traceback.print_stack()
242
self._lock_mode = 'r'
244
self._set_transaction(transactions.ReadOnlyTransaction())
245
# 5K may be excessive, but hey, its a knob.
246
self.get_transaction().set_cache_size(5000)
249
# mutter("unlock: %s (%s)", self, self._lock_count)
250
if not self._lock_mode:
251
raise errors.LockNotHeld(self)
252
if self._lock_count > 1:
253
self._lock_count -= 1
255
#note('unlocking %s', self)
256
#traceback.print_stack()
257
self._finish_transaction()
261
self._lock_mode = self._lock_count = None
264
"""Return true if this LockableFiles group is locked"""
265
return self._lock_count >= 1
267
def get_physical_lock_status(self):
268
"""Return physical lock status.
270
Returns true if a lock is held on the transport. If no lock is held, or
271
the underlying locking mechanism does not support querying lock
272
status, false is returned.
275
return self._lock.peek() is not None
276
except NotImplementedError:
279
def get_transaction(self):
280
"""Return the current active transaction.
282
If no transaction is active, this returns a passthrough object
283
for which all data is immediately flushed and no caching happens.
285
if self._transaction is None:
286
return transactions.PassThroughTransaction()
288
return self._transaction
290
def _set_transaction(self, new_transaction):
291
"""Set a new active transaction."""
292
if self._transaction is not None:
293
raise errors.LockError('Branch %s is in a transaction already.' %
295
self._transaction = new_transaction
297
def _finish_transaction(self):
298
"""Exit the current transaction."""
299
if self._transaction is None:
300
raise errors.LockError('Branch %s is not in a transaction' %
302
transaction = self._transaction
303
self._transaction = None
307
class TransportLock(object):
308
"""Locking method which uses transport-dependent locks.
310
On the local filesystem these transform into OS-managed locks.
312
These do not guard against concurrent access via different
315
This is suitable for use only in WorkingTrees (which are at present
318
def __init__(self, transport, escaped_name, file_modebits, dir_modebits):
319
self._transport = transport
320
self._escaped_name = escaped_name
321
self._file_modebits = file_modebits
322
self._dir_modebits = dir_modebits
324
def break_lock(self):
325
raise NotImplementedError(self.break_lock)
327
def lock_write(self):
328
self._lock = self._transport.lock_write(self._escaped_name)
331
self._lock = self._transport.lock_read(self._escaped_name)
338
raise NotImplementedError()
340
def create(self, mode=None):
341
"""Create lock mechanism"""
342
# for old-style locks, create the file now
343
self._transport.put(self._escaped_name, StringIO(),
344
mode=self._file_modebits)