Refactor to add ObjectStore class.

1 files changed, 153 insertions, 0 deletions

diff --git a/backends/objectstore.py b/backends/objectstore.py
new file mode 100644
index 00000000..e36df72d
--- /dev/null
+++ b/backends/objectstore.py
@@ -0,0 +1,153 @@
+from u1db.backends import CommonBackend
+
+
+class ObjectStore(CommonBackend):
+
+    def __init__(self):
+        self._sync_log = SyncLog()
+        self._transaction_log = TransactionLog()
+
+    #-------------------------------------------------------------------------
+    # implemented methods from Database
+    #-------------------------------------------------------------------------
+
+    def set_document_factory(self, factory):
+        self._factory = factory
+
+    def set_document_size_limit(self, limit):
+        raise NotImplementedError(self.set_document_size_limit)
+
+    def whats_changed(self, old_generation=0):
+        self._get_u1db_data()
+        return self._transaction_log.whats_changed(old_generation)
+
+    def get_doc(self, doc_id, include_deleted=False):
+        doc = self._get_doc(doc_id, check_for_conflicts=True)
+        if doc is None:
+            return None
+        if doc.is_tombstone() and not include_deleted:
+            return None
+        return doc
+
+    def delete_doc(self, doc):
+        old_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
+        if old_doc is None:
+            raise errors.DocumentDoesNotExist
+        if old_doc.rev != doc.rev:
+            raise errors.RevisionConflict()
+        if old_doc.is_tombstone():
+            raise errors.DocumentAlreadyDeleted
+        if old_doc.has_conflicts:
+            raise errors.ConflictedDoc()
+        new_rev = self._allocate_doc_rev(doc.rev)
+        doc.rev = new_rev
+        doc.make_tombstone()
+        self._put_doc(olddoc)
+        return new_rev
+
+    # start of index-related methods: these are not supported by this backend.
+
+    def create_index(self, index_name, *index_expressions):
+        return False
+
+    def delete_index(self, index_name):
+        return False
+
+    def list_indexes(self):
+        return []
+
+    def get_from_index(self, index_name, *key_values):
+        return []
+
+    def get_range_from_index(self, index_name, start_value=None,
+                             end_value=None):
+        return []
+
+    def get_index_keys(self, index_name):
+        return []
+
+    # end of index-related methods: these are not supported by this backend.
+
+    def get_doc_conflicts(self, doc_id):
+        return []
+
+    def resolve_doc(self, doc, conflicted_doc_revs):
+        raise NotImplementedError(self.resolve_doc)
+
+    def _get_replica_gen_and_trans_id(self, other_replica_uid):
+        self._get_u1db_data()
+        return self._sync_log.get_replica_gen_and_trans_id(other_replica_uid)
+
+    def _set_replica_gen_and_trans_id(self, other_replica_uid,
+                                      other_generation, other_transaction_id):
+        self._get_u1db_data()
+        self._sync_log.set_replica_gen_and_trans_id(other_replica_uid,
+                                                    other_generation,
+                                                    other_transaction_id)
+        self._set_u1db_data()
+
+    #-------------------------------------------------------------------------
+    # implemented methods from CommonBackend
+    #-------------------------------------------------------------------------
+
+    def _get_generation(self):
+        self._get_u1db_data()
+        return self._transaction_log.get_generation()
+
+    def _get_generation_info(self):
+        self._get_u1db_data()
+        return self._transaction_log.get_generation_info()
+
+    def _has_conflicts(self, doc_id):
+        # Documents never have conflicts on server.
+        return False
+
+    def _put_and_update_indexes(self, doc_id, old_doc, new_rev, content):
+        raise NotImplementedError(self._put_and_update_indexes)
+
+
+    def _get_trans_id_for_gen(self, generation):
+        self._get_u1db_data()
+        trans_id = self._transaction_log.get_trans_id_for_gen(generation)
+        if trans_id is None:
+            raise errors.InvalidGeneration
+        return trans_id
+
+    def _ensure_u1db_data(self):
+        """
+        Guarantee that u1db data exists in store.
+        """
+        if not self._is_initialized():
+            self._initialize()
+        u1db_data = self._get_doc('u1db_data')
+        self._sync_log.log = u1db_data.content['sync_log']
+        self._transaction_log.log = u1db_data.content['transaction_log']
+
+    def _is_initialized(self):
+        """
+        Verify if u1db data exists in store.
+        """
+        if not self._get_doc('u1db_data'):
+            return False
+        return True
+
+    def _initialize(self):
+        """
+        Create u1db data object in store.
+        """
+        content = { 'transaction_log' : [],
+                    'sync_log' : [] }
+        doc = self.create_doc('u1db_data', content)
+
+    def _get_u1db_data(self):
+        data = self.get_doc('u1db_data').content
+        self._transaction_log = data['transaction_log']
+        self._sync_log = data['sync_log']
+
+    def _set_u1db_data(self):
+        doc = self._factory('u1db_data')
+        doc.content = { 'transaction_log' : self._transaction_log,
+                        'sync_log'        : self._sync_log }
+        self.put_doc(doc)
+
+