zhijiangW commented on a change in pull request #11515: [FLINK-16744][task] implement channel state persistence for unaligned checkpoints URL: https://github.com/apache/flink/pull/11515#discussion_r402267095
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/channel/RefCountingFSDataInputStream.java ########## @@ -0,0 +1,126 @@ +/* + * 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. + */ + +package org.apache.flink.runtime.checkpoint.channel; + +import org.apache.flink.core.fs.FSDataInputStream; +import org.apache.flink.runtime.state.AbstractChannelStateHandle; +import org.apache.flink.runtime.state.StreamStateHandle; +import org.apache.flink.util.Preconditions; +import org.apache.flink.util.function.SupplierWithException; + +import javax.annotation.concurrent.NotThreadSafe; + +import java.io.IOException; +import java.util.HashMap; +import java.util.Map; + +import static org.apache.flink.util.Preconditions.checkState; + +@NotThreadSafe +class RefCountingFSDataInputStream extends FSDataInputStream { + + @NotThreadSafe + static class RefCountingFSDataInputStreamFactory { + private final Map<StreamStateHandle, RefCountingFSDataInputStream> map = new HashMap<>(); // not clearing: expecting short life + private final ChannelStateDeserializer serializer; + + RefCountingFSDataInputStreamFactory(ChannelStateDeserializer serializer) { + this.serializer = serializer; + } + + <T> RefCountingFSDataInputStream forHandle(AbstractChannelStateHandle<T> handle) { + StreamStateHandle streamStateHandle = handle.getDelegate(); + RefCountingFSDataInputStream stream = map.get(streamStateHandle); + if (stream == null) { + stream = new RefCountingFSDataInputStream(streamStateHandle::openInputStream, serializer); + map.put(streamStateHandle, stream); + } + return stream; + } + + ChannelStateDeserializer getSerializer() { + return serializer; + } + } + + private enum State {NEW, OPENED, CLOSED} + + private final SupplierWithException<FSDataInputStream, IOException> streamSupplier; + private FSDataInputStream stream; + private final ChannelStateDeserializer serializer; + private int numReaders = 0; + private State state = State.NEW; + + private RefCountingFSDataInputStream(SupplierWithException<FSDataInputStream, IOException> streamSupplier, ChannelStateDeserializer serializer) { + this.streamSupplier = streamSupplier; + this.serializer = serializer; + } + + void incNumReaders() { + checkNotClosed(); + numReaders++; + } + + void decNumReaders() throws IOException { + checkNotClosed(); + numReaders--; + if (numReaders == 0) { + close(); + } + } + + @Override + public int read() throws IOException { + ensureOpen(); + return stream.read(); + } + + @Override + public void seek(long desired) throws IOException { Review comment: nit: desired -> pos ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
