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# Copyright 2019 New Vector Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
from typing import Any, Dict, List, Optional, Tuple
import attr
from synapse.api.errors import SynapseError
from synapse.types import JsonDict
logger = logging.getLogger(__name__)
@attr.s(slots=True)
class PaginationChunk:
"""Returned by relation pagination APIs.
Attributes:
chunk: The rows returned by pagination
next_batch: Token to fetch next set of results with, if
None then there are no more results.
prev_batch: Token to fetch previous set of results with, if
None then there are no previous results.
"""
chunk = attr.ib(type=List[JsonDict])
next_batch = attr.ib(type=Optional[Any], default=None)
prev_batch = attr.ib(type=Optional[Any], default=None)
def to_dict(self) -> Dict[str, Any]:
d = {"chunk": self.chunk}
if self.next_batch:
d["next_batch"] = self.next_batch.to_string()
if self.prev_batch:
d["prev_batch"] = self.prev_batch.to_string()
return d
@attr.s(frozen=True, slots=True)
class RelationPaginationToken:
"""Pagination token for relation pagination API.
As the results are in topological order, we can use the
`topological_ordering` and `stream_ordering` fields of the events at the
boundaries of the chunk as pagination tokens.
Attributes:
topological: The topological ordering of the boundary event
stream: The stream ordering of the boundary event.
"""
topological = attr.ib(type=int)
stream = attr.ib(type=int)
@staticmethod
def from_string(string: str) -> "RelationPaginationToken":
try:
t, s = string.split("-")
return RelationPaginationToken(int(t), int(s))
except ValueError:
raise SynapseError(400, "Invalid token")
def to_string(self) -> str:
return "%d-%d" % (self.topological, self.stream)
def as_tuple(self) -> Tuple[Any, ...]:
return attr.astuple(self)
@attr.s(frozen=True, slots=True)
class AggregationPaginationToken:
"""Pagination token for relation aggregation pagination API.
As the results are order by count and then MAX(stream_ordering) of the
aggregation groups, we can just use them as our pagination token.
Attributes:
count: The count of relations in the boundary group.
stream: The MAX stream ordering in the boundary group.
"""
count = attr.ib(type=int)
stream = attr.ib(type=int)
@staticmethod
def from_string(string: str) -> "AggregationPaginationToken":
try:
c, s = string.split("-")
return AggregationPaginationToken(int(c), int(s))
except ValueError:
raise SynapseError(400, "Invalid token")
def to_string(self) -> str:
return "%d-%d" % (self.count, self.stream)
def as_tuple(self) -> Tuple[Any, ...]:
return attr.astuple(self)
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