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# Copyright (C) 2005 by Canonical Development 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
# TODO: Could remember a bias towards whether a particular store is typically
# compressed or not.
"""
Stores are the main data-storage mechanism for Bazaar-NG.
A store is a simple write-once container indexed by a universally
unique ID.
"""
from bzrlib.errors import BzrError, UnlistableStore
from bzrlib.trace import mutter
import bzrlib.transport
######################################################################
# stores
class StoreError(Exception):
pass
class Store(object):
"""This class represents the abstract storage layout for saving information.
"""
_transport = None
_max_buffered_requests = 10
def __init__(self, transport):
assert isinstance(transport, bzrlib.transport.Transport)
self._transport = transport
def __repr__(self):
if self._transport is None:
return "%s(None)" % (self.__class__.__name__)
else:
return "%s(%r)" % (self.__class__.__name__, self._transport.base)
__str__ = __repr__
def __len__(self):
raise NotImplementedError('Children should define their length')
def __getitem__(self, fileid):
"""Returns a file reading from a particular entry."""
raise NotImplementedError
def __contains__(self, fileid):
""""""
raise NotImplementedError
def __iter__(self):
raise NotImplementedError
def __del__(self):
"""Delete an entry from the store."""
raise NotImplementedError('Children need to define delete rights.')
def add(self, f, fileid):
"""Add a file object f to the store accessible from the given fileid"""
raise NotImplementedError('Children of Store must define their method of adding entries.')
def add_multi(self, entries):
"""Add a series of file-like or string objects to the store with the given
identities.
:param entries: A list of tuples of file,id pairs [(file1, id1), (file2, id2), ...]
This could also be a generator yielding (file,id) pairs.
"""
for f, fileid in entries:
self.add(f, fileid)
def has(self, fileids):
"""Return True/False for each entry in fileids.
:param fileids: A List or generator yielding file ids.
:return: A generator or list returning True/False for each entry.
"""
for fileid in fileids:
if fileid in self:
yield True
else:
yield False
def get(self, fileids, permit_failure=False, pb=None):
"""Return a set of files, one for each requested entry.
:param permit_failure: If true, return None for entries which do not
exist.
:return: A list or generator of file-like objects, one for each id.
"""
for fileid in fileids:
try:
yield self[fileid]
except KeyError:
if permit_failure:
yield None
else:
raise
def copy_multi(self, other, ids, pb=None, permit_failure=False):
"""Copy texts for ids from other into self.
If an id is present in self, it is skipped. A count of copied
ids is returned, which may be less than len(ids).
:param other: Another Store object
:param ids: A list of entry ids to be copied
:param pb: A ProgressBar object, if none is given, the default will be created.
:param permit_failure: Allow missing entries to be ignored
:return: (n_copied, [failed]) The number of entries copied successfully,
followed by a list of entries which could not be copied (because they
were missing)
"""
if pb is None:
pb = bzrlib.ui.ui_factory.progress_bar()
ids = list(ids) # Make sure we don't have a generator, since we iterate 2 times
pb.update('preparing to copy')
to_copy = []
for file_id, has in zip(ids, self.has(ids)):
if not has:
to_copy.append(file_id)
return self._do_copy(other, to_copy, pb, permit_failure=permit_failure)
def _do_copy(self, other, to_copy, pb, permit_failure=False):
"""This is the standard copying mechanism, just get them one at
a time from remote, and store them locally.
:param other: Another Store object
:param to_copy: A list of entry ids to copy
:param pb: A ProgressBar object to display completion status.
:param permit_failure: Allow missing entries to be ignored
:return: (n_copied, [failed])
The number of entries copied, and a list of failed entries.
"""
# This should be updated to use add_multi() rather than
# the current methods of buffering requests.
# One question, is it faster to queue up 1-10 and then copy 1-10
# then queue up 11-20, copy 11-20
# or to queue up 1-10, copy 1, queue 11, copy 2, etc?
# sort of pipeline versus batch.
# We can't use self._transport.copy_to because we don't know
# whether the local tree is in the same format as other
failed = set()
def buffer_requests():
count = 0
buffered_requests = []
for fileid in to_copy:
try:
f = other[fileid]
except KeyError:
if permit_failure:
failed.add(fileid)
continue
else:
raise
buffered_requests.append((f, fileid))
if len(buffered_requests) > self._max_buffered_requests:
yield buffered_requests.pop(0)
count += 1
pb.update('copy', count, len(to_copy))
for req in buffered_requests:
yield req
count += 1
pb.update('copy', count, len(to_copy))
assert count == len(to_copy)
self.add_multi(buffer_requests())
pb.clear()
return len(to_copy), failed
def copy_all(store_from, store_to):
"""Copy all ids from one store to another."""
if not hasattr(store_from, "__iter__"):
raise UnlistableStore(store_from)
try:
ids = [f for f in store_from]
except NotImplementedError:
raise UnlistableStore(store_from)
store_to.copy_multi(store_from, ids)
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