def _ProjectionPartialEntityGenerator(cursor):
"""Generator that creates partial entities for projection.
Generate partial datastore entities from a cursor, holding only the values
being projected. These entities might share a key.
Args:
cursor: a SQLite3.Cursor or subclass.
Yields:
Partial entities resulting from the projection.
"""
for row in cursor:
entity_original = entity_pb.EntityProto(row[1])
entity = entity_pb.EntityProto()
entity.mutable_key().MergeFrom(entity_original.key())
entity.mutable_entity_group().MergeFrom(entity_original.entity_group())
for name, value_data in zip(row[2::2], row[3::2]):
prop_to_add = entity.add_property()
prop_to_add.set_name(ToUtf8(name))
value_decoder = sortable_pb_encoder.Decoder(
array.array('B', str(value_data)))
prop_to_add.mutable_value().Merge(value_decoder)
prop_to_add.set_multiple(False)
datastore_stub_util._ScrubMetadataProperty(entity)
datastore_stub_util.PrepareSpecialPropertiesForLoad(entity)
yield entity
def _GetEntitiesInEntityGroup(self, entity_group):
query = datastore_pb.Query()
query.set_app(entity_group.app())
if entity_group.name_space():
query.set_name_space(entity_group.name_space())
query.mutable_ancestor().CopyFrom(entity_group)
filter_info = self.__GenerateFilterInfo(query.filter_list(), query)
order_info = self.__GenerateOrderInfo(query.order_list())
sql_stmt, params = self.__KindQuery(query, filter_info, order_info)
conn = self._GetConnection()
try:
db_cursor = conn.execute(sql_stmt, params)
entities = {}
for row in db_cursor.fetchall():
entity = entity_pb.EntityProto(row[1])
datastore_stub_util._ScrubMetadataProperty(entity)
entities[datastore_types.ReferenceToKeyValue(entity.key())] = entity
return entities
finally:
self._ReleaseConnection(conn)
def _Get(self, key):
conn = self._GetConnection()
try:
prefix = self._GetTablePrefix(key)
c = conn.execute(
'SELECT entity FROM "%s!Entities" WHERE __path__ = ?' % (prefix,),
(self.__EncodeIndexPB(key.path()),))
row = c.fetchone()
if row:
entity = entity_pb.EntityProto()
entity.ParseFromString(row[0])
datastore_stub_util._ScrubMetadataProperty(entity)
return datastore_stub_util.LoadEntity(entity)
finally:
self._ReleaseConnection(conn)
def Read(self):
""" Reads the datastore and history files into memory.
The in-memory query history is cleared, but the datastore is *not*
cleared; the entities in the files are merged into the entities in memory.
If you want them to overwrite the in-memory datastore, call Clear() before
calling Read().
If the datastore file contains an entity with the same app name, kind, and
key as an entity already in the datastore, the entity from the file
overwrites the entity in the datastore.
Also sets each ID counter to one greater than the highest ID allocated so
far in that counter's ID space.
"""
if self.__datastore_file and self.__datastore_file != '/dev/null':
for encoded_entity in self.__ReadPickled(self.__datastore_file):
try:
entity = entity_pb.EntityProto(encoded_entity)
datastore_stub_util._ScrubMetadataProperty(entity)
except self.READ_PB_EXCEPTIONS, e:
raise apiproxy_errors.ApplicationError(
datastore_pb.Error.INTERNAL_ERROR,
self.READ_ERROR_MSG % (self.__datastore_file, e))
except struct.error, e:
if (sys.version_info[0:3] == (2, 5, 0)
and e.message.startswith('unpack requires a string argument')):
raise apiproxy_errors.ApplicationError(
datastore_pb.Error.INTERNAL_ERROR,
self.READ_PY250_MSG + self.READ_ERROR_MSG %
(self.__datastore_file, e))
else:
raise
self._StoreEntity(entity)
last_path = _FinalElement(entity.key())
if last_path.id():
self._SetMaxId(last_path.id())
def _DedupingEntityGenerator(cursor):
"""Generator that removes duplicate entities from the results.
Generate datastore entities from a cursor, skipping the duplicates
Args:
cursor: a SQLite3.Cursor or subclass.
Yields:
Entities that do not share a key.
"""
seen = set()
for row in cursor:
row_key, row_entity = row[:2]
encoded_row_key = str(row_key)
if encoded_row_key in seen:
continue
seen.add(encoded_row_key)
entity = entity_pb.EntityProto(row_entity)
datastore_stub_util._ScrubMetadataProperty(entity)
datastore_stub_util.PrepareSpecialPropertiesForLoad(entity)
yield entity
