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Diffstat (limited to 'u1db/backends/__init__.py')
| -rw-r--r-- | u1db/backends/__init__.py | 211 |
1 files changed, 0 insertions, 211 deletions
diff --git a/u1db/backends/__init__.py b/u1db/backends/__init__.py deleted file mode 100644 index c8e5adc6..00000000 --- a/u1db/backends/__init__.py +++ /dev/null @@ -1,211 +0,0 @@ -# Copyright 2011 Canonical Ltd. -# -# This file is part of u1db. -# -# u1db is free software: you can redistribute it and/or modify -# it under the terms of the GNU Lesser General Public License version 3 -# as published by the Free Software Foundation. -# -# u1db 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 Lesser General Public License for more details. -# -# You should have received a copy of the GNU Lesser General Public License -# along with u1db. If not, see <http://www.gnu.org/licenses/>. - -"""Abstract classes and common implementations for the backends.""" - -import re -try: - import simplejson as json -except ImportError: - import json # noqa -import uuid - -import u1db -from u1db import ( - errors, -) -import u1db.sync -from u1db.vectorclock import VectorClockRev - - -check_doc_id_re = re.compile("^" + u1db.DOC_ID_CONSTRAINTS + "$", re.UNICODE) - - -class CommonSyncTarget(u1db.sync.LocalSyncTarget): - pass - - -class CommonBackend(u1db.Database): - - document_size_limit = 0 - - def _allocate_doc_id(self): - """Generate a unique identifier for this document.""" - return 'D-' + uuid.uuid4().hex # 'D-' stands for document - - def _allocate_transaction_id(self): - return 'T-' + uuid.uuid4().hex # 'T-' stands for transaction - - def _allocate_doc_rev(self, old_doc_rev): - vcr = VectorClockRev(old_doc_rev) - vcr.increment(self._replica_uid) - return vcr.as_str() - - def _check_doc_id(self, doc_id): - if not check_doc_id_re.match(doc_id): - raise errors.InvalidDocId() - - def _check_doc_size(self, doc): - if not self.document_size_limit: - return - if doc.get_size() > self.document_size_limit: - raise errors.DocumentTooBig - - def _get_generation(self): - """Return the current generation. - - """ - raise NotImplementedError(self._get_generation) - - def _get_generation_info(self): - """Return the current generation and transaction id. - - """ - raise NotImplementedError(self._get_generation_info) - - def _get_doc(self, doc_id, check_for_conflicts=False): - """Extract the document from storage. - - This can return None if the document doesn't exist. - """ - raise NotImplementedError(self._get_doc) - - def _has_conflicts(self, doc_id): - """Return True if the doc has conflicts, False otherwise.""" - raise NotImplementedError(self._has_conflicts) - - def create_doc(self, content, doc_id=None): - json_string = json.dumps(content) - if doc_id is None: - doc_id = self._allocate_doc_id() - doc = self._factory(doc_id, None, json_string) - self.put_doc(doc) - return doc - - def create_doc_from_json(self, json, doc_id=None): - if doc_id is None: - doc_id = self._allocate_doc_id() - doc = self._factory(doc_id, None, json) - self.put_doc(doc) - return doc - - def _get_transaction_log(self): - """This is only for the test suite, it is not part of the api.""" - raise NotImplementedError(self._get_transaction_log) - - def _put_and_update_indexes(self, doc_id, old_doc, new_rev, content): - raise NotImplementedError(self._put_and_update_indexes) - - def get_docs(self, doc_ids, check_for_conflicts=True, - include_deleted=False): - for doc_id in doc_ids: - doc = self._get_doc( - doc_id, check_for_conflicts=check_for_conflicts) - if doc.is_tombstone() and not include_deleted: - continue - yield doc - - def _get_trans_id_for_gen(self, generation): - """Get the transaction id corresponding to a particular generation. - - Raises an InvalidGeneration when the generation does not exist. - - """ - raise NotImplementedError(self._get_trans_id_for_gen) - - def validate_gen_and_trans_id(self, generation, trans_id): - """Validate the generation and transaction id. - - Raises an InvalidGeneration when the generation does not exist, and an - InvalidTransactionId when it does but with a different transaction id. - - """ - if generation == 0: - return - known_trans_id = self._get_trans_id_for_gen(generation) - if known_trans_id != trans_id: - raise errors.InvalidTransactionId - - def _validate_source(self, other_replica_uid, other_generation, - other_transaction_id): - """Validate the new generation and transaction id. - - other_generation must be greater than what we have stored for this - replica, *or* it must be the same and the transaction_id must be the - same as well. - """ - (old_generation, - old_transaction_id) = self._get_replica_gen_and_trans_id( - other_replica_uid) - if other_generation < old_generation: - raise errors.InvalidGeneration - if other_generation > old_generation: - return - if other_transaction_id == old_transaction_id: - return - raise errors.InvalidTransactionId - - def _put_doc_if_newer(self, doc, save_conflict, replica_uid, replica_gen, - replica_trans_id=''): - cur_doc = self._get_doc(doc.doc_id) - doc_vcr = VectorClockRev(doc.rev) - if cur_doc is None: - cur_vcr = VectorClockRev(None) - else: - cur_vcr = VectorClockRev(cur_doc.rev) - self._validate_source(replica_uid, replica_gen, replica_trans_id) - if doc_vcr.is_newer(cur_vcr): - rev = doc.rev - self._prune_conflicts(doc, doc_vcr) - if doc.rev != rev: - # conflicts have been autoresolved - state = 'superseded' - else: - state = 'inserted' - self._put_and_update_indexes(cur_doc, doc) - elif doc.rev == cur_doc.rev: - # magical convergence - state = 'converged' - elif cur_vcr.is_newer(doc_vcr): - # Don't add this to seen_ids, because we have something newer, - # so we should send it back, and we should not generate a - # conflict - state = 'superseded' - elif cur_doc.same_content_as(doc): - # the documents have been edited to the same thing at both ends - doc_vcr.maximize(cur_vcr) - doc_vcr.increment(self._replica_uid) - doc.rev = doc_vcr.as_str() - self._put_and_update_indexes(cur_doc, doc) - state = 'superseded' - else: - state = 'conflicted' - if save_conflict: - self._force_doc_sync_conflict(doc) - if replica_uid is not None and replica_gen is not None: - self._do_set_replica_gen_and_trans_id( - replica_uid, replica_gen, replica_trans_id) - return state, self._get_generation() - - def _ensure_maximal_rev(self, cur_rev, extra_revs): - vcr = VectorClockRev(cur_rev) - for rev in extra_revs: - vcr.maximize(VectorClockRev(rev)) - vcr.increment(self._replica_uid) - return vcr.as_str() - - def set_document_size_limit(self, limit): - self.document_size_limit = limit |