sven-weber-db commented on code in PR #55515: URL: https://github.com/apache/spark/pull/55515#discussion_r3180441464
########## python/pyspark/messages/zero_copy_byte_stream.py: ########## @@ -0,0 +1,177 @@ +# +# Licensed to the Apache Software Foundation (ASF) under one or more +# contributor license agreements. See the NOTICE file distributed with +# this work for additional information regarding copyright ownership. +# The ASF licenses this file to You 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 threading +from typing import Optional +from collections import deque + + +class ZeroCopyByteStream: + """ + Accepts chunks of bytes as zero-copy memory views. Implements + a file-like interface on top of the received chunks. + + read() calls that access bytes from a single chunk are served + as zero-copy reads. If a read() call crosses chunk boundaries, + memory copies are required. The later case is unexpected and only + implemented for correctness. + + This implementation is thread-safe. + """ + + def __init__(self, initial_view: Optional[memoryview] = None): + if not isinstance(initial_view, memoryview) and initial_view is not None: + raise TypeError( + "Only memoryview and None are allowed as the initial " + + f"ZeroCopyByteStream view. Recveied type {type(initial_view)} instead." + ) + + self._chunks = deque[memoryview]() + self._current_chunk = initial_view + self._current_position = 0 + self._eof = False + self._lock = threading.Lock() Review Comment: I think using a `RLock` in this case is fine. I removed the `threading.Lock` in favour of using the default `RLock` from `Condition`. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
